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• Computer Networks UNISA - Chap 10 &ndash; In Depth TCP/IP Networking

  - by MarkPearl

  After reading this section you should be able to Understand methods of network design unique to TCP/IP networks, including subnetting, CIDR, and address translation Explain the differences between public and private TCP/IP networks Describe protocols used between mail clients and mail servers, including SMTP, POP3, and IMAP4 Employ multiple TCP/IP utilities for network discovery and troubleshooting Designing TCP/IP-Based Networks The following sections explain how network and host information in an IPv4 address can be manipulated to subdivide networks into smaller segments. Subnetting Subnetting separates a network into multiple logically defined segments, or subnets. Networks are commonly subnetted according to geographic locations, departmental boundaries, or technology types. A network administrator might separate traffic to accomplish the following… Enhance security Improve performance Simplify troubleshooting The challenges of Classful Addressing in IPv4 (No subnetting) The simplest type of IPv4 is known as classful addressing (which was the Class A, Class B & Class C network addresses). Classful addressing has the following limitations. Restriction in the number of usable IPv4 addresses (class C would be limited to 254 addresses) Difficult to separate traffic from various parts of a network Because of the above reasons, subnetting was introduced. IPv4 Subnet Masks Subnetting depends on the use of subnet masks to identify how a network is subdivided. A subnet mask indicates where network information is located in an IPv4 address. The 1 in a subnet mask indicates that corresponding bits in the IPv4 address contain network information (likewise 0 indicates the opposite) Each network class is associated with a default subnet mask… Class A = 255.0.0.0 Class B = 255.255.0.0 Class C = 255.255.255.0 An example of calculating  the network ID for a particular device with a subnet mask is shown below.. IP Address = 199.34.89.127 Subnet Mask = 255.255.255.0 Resultant Network ID = 199.34.89.0 IPv4 Subnetting Techniques Subnetting breaks the rules of classful IPv4 addressing. Read page 490 for a detailed explanation Calculating IPv4 Subnets Read page 491 – 494 for an explanation Important… Subnetting only applies to the devices internal to your network. Everything external looks at the class of the IP address instead of the subnet network ID. This way, traffic directed to your network externally still knows where to go, and once it has entered your internal network it can then be prioritized and segmented. CIDR (classless Interdomain Routing) CIDR is also known as classless routing or supernetting. In CIDR conventional network class distinctions do not exist, a subnet boundary can move to the left, therefore generating more usable IP addresses on your network. A subnet created by moving the subnet boundary to the left is known as a supernet. With CIDR also came new shorthand for denoting the position of subnet boundaries known as CIDR notation or slash notation. CIDR notation takes the form of the network ID followed by a forward slash (/) followed by the number of bits that are used for the extended network prefix. To take advantage of classless routing, your networks routers must be able to interpret IP addresses that don;t adhere to conventional network class parameters. Routers that rely on older routing protocols (i.e. RIP) are not capable of interpreting classless IP addresses. Internet Gateways Gateways are a combination of software and hardware that enable two different network segments to exchange data. A gateway facilitates communication between different networks or subnets. Because on device cannot send data directly to a device on another subnet, a gateway must intercede and hand off the information. Every device on a TCP/IP based network has a default gateway (a gateway that first interprets its outbound requests to other subnets, and then interprets its inbound requests from other subnets). The internet contains a vast number of routers and gateways. If each gateway had to track addressing information for every other gateway on the Internet, it would be overtaxed. Instead, each handles only a relatively small amount of addressing information, which it uses to forward data to another gateway that knows more about the data’s destination. The gateways that make up the internet backbone are called core gateways. Address Translation An organizations default gateway can also be used to “hide” the organizations internal IP addresses and keep them from being recognized on a public network. A public network is one that any user may access with little or no restrictions. On private networks, hiding IP addresses allows network managers more flexibility in assigning addresses. Clients behind a gateway may use any IP addressing scheme, regardless of whether it is recognized as legitimate by the Internet authorities but as soon as those devices need to go on the internet, they must have legitimate IP addresses to exchange data. When a clients transmission reaches the default gateway, the gateway opens the IP datagram and replaces the client’s private IP address with an Internet recognized IP address. This process is known as NAT (Network Address Translation). TCP/IP Mail Services All Internet mail services rely on the same principles of mail delivery, storage, and pickup, though they may use different types of software to accomplish these functions. Email servers and clients communicate through special TCP/IP application layer protocols. These protocols, all of which operate on a variety of operating systems are discussed below… SMTP (Simple Mail transfer Protocol) The protocol responsible for moving messages from one mail server to another over TCP/IP based networks. SMTP belongs to the application layer of the ODI model and relies on TCP as its transport protocol. Operates from port 25 on the SMTP server Simple sub-protocol, incapable of doing anything more than transporting mail or holding it in a queue MIME (Multipurpose Internet Mail Extensions) The standard message format specified by SMTP allows for lines that contain no more than 1000 ascii characters meaning if you relied solely on SMTP you would have very short messages and nothing like pictures included in an email. MIME us a standard for encoding and interpreting binary files, images, video, and non-ascii character sets within an email message. MIME identifies each element of a mail message according to content type. MIME does not replace SMTP but works in conjunction with it. Most modern email clients and servers support MIME POP (Post Office Protocol) POP is an application layer protocol used to retrieve messages from a mail server POP3 relies on TCP and operates over port 110 With POP3 mail is delivered and stored on a mail server until it is downloaded by a user Disadvantage of POP3 is that it typically does not allow users to save their messages on the server because of this IMAP is sometimes used IMAP (Internet Message Access Protocol) IMAP is a retrieval protocol that was developed as a more sophisticated alternative to POP3 The single biggest advantage IMAP4 has over POP3 is that users can store messages on the mail server, rather than having to continually download them Users can retrieve all or only a portion of any mail message Users can review their messages and delete them while the messages remain on the server Users can create sophisticated methods of organizing messages on the server Users can share a mailbox in a central location Disadvantages of IMAP are typically related to the fact that it requires more storage space on the server. Additional TCP/IP Utilities Nearly all TCP/IP utilities can be accessed from the command prompt on any type of server or client running TCP/IP. The syntaxt may differ depending on the OS of the client. Below is a list of additional TCP/IP utilities – research their use on your own! Ipconfig (Windows) & Ifconfig (Linux) Netstat Nbtstat Hostname, Host & Nslookup Dig (Linux) Whois (Linux) Traceroute (Tracert) Mtr (my traceroute) Route

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• Online ALTER TABLE in MySQL 5.6

  - by Marko Mäkelä

  This is the low-level view of data dictionary language (DDL) operations in the InnoDB storage engine in MySQL 5.6. John Russell gave a more high-level view in his blog post April 2012 Labs Release – Online DDL Improvements. MySQL before the InnoDB Plugin Traditionally, the MySQL storage engine interface has taken a minimalistic approach to data definition language. The only natively supported operations were CREATE TABLE, DROP TABLE and RENAME TABLE. Consider the following example: CREATE TABLE t(a INT); INSERT INTO t VALUES (1),(2),(3); CREATE INDEX a ON t(a); DROP TABLE t; The CREATE INDEX statement would be executed roughly as follows: CREATE TABLE temp(a INT, INDEX(a)); INSERT INTO temp SELECT * FROM t; RENAME TABLE t TO temp2; RENAME TABLE temp TO t; DROP TABLE temp2; You could imagine that the database could crash when copying all rows from the original table to the new one. For example, it could run out of file space. Then, on restart, InnoDB would roll back the huge INSERT transaction. To fix things a little, a hack was added to ha_innobase::write_row for committing the transaction every 10,000 rows. Still, it was frustrating that even a simple DROP INDEX would make the table unavailable for modifications for a long time. Fast Index Creation in the InnoDB Plugin of MySQL 5.1 MySQL 5.1 introduced a new interface for CREATE INDEX and DROP INDEX. The old table-copying approach can still be forced by SET old_alter_table=0. This interface is used in MySQL 5.5 and in the InnoDB Plugin for MySQL 5.1. Apart from the ability to do a quick DROP INDEX, the main advantage is that InnoDB will execute a merge-sort algorithm before inserting the index records into each index that is being created. This should speed up the insert into the secondary index B-trees and potentially result in a better B-tree fill factor. The 5.1 ALTER TABLE interface was not perfect. For example, DROP FOREIGN KEY still invoked the table copy. Renaming columns could conflict with InnoDB foreign key constraints. Combining ADD KEY and DROP KEY in ALTER TABLE was problematic and not atomic inside the storage engine. The ALTER TABLE interface in MySQL 5.6 The ALTER TABLE storage engine interface was completely rewritten in MySQL 5.6. Instead of introducing a method call for every conceivable operation, MySQL 5.6 introduced a handful of methods, and data structures that keep track of the requested changes. In MySQL 5.6, online ALTER TABLE operation can be requested by specifying LOCK=NONE. Also LOCK=SHARED and LOCK=EXCLUSIVE are available. The old-style table copying can be requested by ALGORITHM=COPY. That one will require at least LOCK=SHARED. From the InnoDB point of view, anything that is possible with LOCK=EXCLUSIVE is also possible with LOCK=SHARED. Most ALGORITHM=INPLACE operations inside InnoDB can be executed online (LOCK=NONE). InnoDB will always require an exclusive table lock in two phases of the operation. The execution phases are tied to a number of methods: handler::check_if_supported_inplace_alter Checks if the storage engine can perform all requested operations, and if so, what kind of locking is needed. handler::prepare_inplace_alter_table InnoDB uses this method to set up the data dictionary cache for upcoming CREATE INDEX operation. We need stubs for the new indexes, so that we can keep track of changes to the table during online index creation. Also, crash recovery would drop any indexes that were incomplete at the time of the crash. handler::inplace_alter_table In InnoDB, this method is used for creating secondary indexes or for rebuilding the table. This is the ‘main’ phase that can be executed online (with concurrent writes to the table). handler::commit_inplace_alter_table This is where the operation is committed or rolled back. Here, InnoDB would drop any indexes, rename any columns, drop or add foreign keys, and finalize a table rebuild or index creation. It would also discard any logs that were set up for online index creation or table rebuild. The prepare and commit phases require an exclusive lock, blocking all access to the table. If MySQL times out while upgrading the table meta-data lock for the commit phase, it will roll back the ALTER TABLE operation. In MySQL 5.6, data definition language operations are still not fully atomic, because the data dictionary is split. Part of it is inside InnoDB data dictionary tables. Part of the information is only available in the *.frm file, which is not covered by any crash recovery log. But, there is a single commit phase inside the storage engine. Online Secondary Index Creation It may occur that an index needs to be created on a new column to speed up queries. But, it may be unacceptable to block modifications on the table while creating the index. It turns out that it is conceptually not so hard to support online index creation. All we need is some more execution phases: Set up a stub for the index, for logging changes. Scan the table for index records. Sort the index records. Bulk load the index records. Apply the logged changes. Replace the stub with the actual index. Threads that modify the table will log the operations to the logs of each index that is being created. Errors, such as log overflow or uniqueness violations, will only be flagged by the ALTER TABLE thread. The log is conceptually similar to the InnoDB change buffer. The bulk load of index records will bypass record locking. We still generate redo log for writing the index pages. It would suffice to log page allocations only, and to flush the index pages from the buffer pool to the file system upon completion. Native ALTER TABLE Starting with MySQL 5.6, InnoDB supports most ALTER TABLE operations natively. The notable exceptions are changes to the column type, ADD FOREIGN KEY except when foreign_key_checks=0, and changes to tables that contain FULLTEXT indexes. The keyword ALGORITHM=INPLACE is somewhat misleading, because certain operations cannot be performed in-place. For example, changing the ROW_FORMAT of a table requires a rebuild. Online operation (LOCK=NONE) is not allowed in the following cases: when adding an AUTO_INCREMENT column, when the table contains FULLTEXT indexes or a hidden FTS_DOC_ID column, or when there are FOREIGN KEY constraints referring to the table, with ON…CASCADE or ON…SET NULL option. The FOREIGN KEY limitations are needed, because MySQL does not acquire meta-data locks on the child or parent tables when executing SQL statements. Theoretically, InnoDB could support operations like ADD COLUMN and DROP COLUMN in-place, by lazily converting the table to a newer format. This would require that the data dictionary keep multiple versions of the table definition. For simplicity, we will copy the entire table, even for DROP COLUMN. The bulk copying of the table will bypass record locking and undo logging. For facilitating online operation, a temporary log will be associated with the clustered index of table. Threads that modify the table will also write the changes to the log. When altering the table, we skip all records that have been marked for deletion. In this way, we can simply discard any undo log records that were not yet purged from the original table. Off-page columns, or BLOBs, are an important consideration. We suspend the purge of delete-marked records if it would free any off-page columns from the old table. This is because the BLOBs can be needed when applying changes from the log. We have special logging for handling the ROLLBACK of an INSERT that inserted new off-page columns. This is because the columns will be freed at rollback.

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• GLSL: Strange light reflections

  - by Tom

  According to this tutorial I'm trying to make a normal mapping using GLSL, but something is wrong and I can't find the solution. The output render is in this image: Image1 in this image is a plane with two triangles and each of it is different illuminated (that is bad). The plane has 6 vertices. In the upper left side of this plane are 2 identical vertices (same in the lower right). Here are some vectors same for each vertice: normal vector = 0, 1, 0 (red lines on image) tangent vector = 0, 0,-1 (green lines on image) bitangent vector = -1, 0, 0 (blue lines on image) here I have one question: The two identical vertices does need to have the same tangent and bitangent? I have tried to make other values to the tangents but the effect was still similar. Here are my shaders Vertex shader: #version 130 // Input vertex data, different for all executions of this shader. in vec3 vertexPosition_modelspace; in vec2 vertexUV; in vec3 vertexNormal_modelspace; in vec3 vertexTangent_modelspace; in vec3 vertexBitangent_modelspace; // Output data ; will be interpolated for each fragment. out vec2 UV; out vec3 Position_worldspace; out vec3 EyeDirection_cameraspace; out vec3 LightDirection_cameraspace; out vec3 LightDirection_tangentspace; out vec3 EyeDirection_tangentspace; // Values that stay constant for the whole mesh. uniform mat4 MVP; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Output position of the vertex, in clip space : MVP * position gl_Position = MVP * vec4(vertexPosition_modelspace,1); // Position of the vertex, in worldspace : M * position Position_worldspace = (M * vec4(vertexPosition_modelspace,1)).xyz; // Vector that goes from the vertex to the camera, in camera space. // In camera space, the camera is at the origin (0,0,0). vec3 vertexPosition_cameraspace = ( V * M * vec4(vertexPosition_modelspace,1)).xyz; EyeDirection_cameraspace = vec3(0,0,0) - vertexPosition_cameraspace; // Vector that goes from the vertex to the light, in camera space. M is ommited because it's identity. vec3 LightPosition_cameraspace = ( V * vec4(LightPosition_worldspace,1)).xyz; LightDirection_cameraspace = LightPosition_cameraspace + EyeDirection_cameraspace; // UV of the vertex. No special space for this one. UV = vertexUV; // model to camera = ModelView vec3 vertexTangent_cameraspace = MV3x3 * vertexTangent_modelspace; vec3 vertexBitangent_cameraspace = MV3x3 * vertexBitangent_modelspace; vec3 vertexNormal_cameraspace = MV3x3 * vertexNormal_modelspace; mat3 TBN = transpose(mat3( vertexTangent_cameraspace, vertexBitangent_cameraspace, vertexNormal_cameraspace )); // You can use dot products instead of building this matrix and transposing it. See References for details. LightDirection_tangentspace = TBN * LightDirection_cameraspace; EyeDirection_tangentspace = TBN * EyeDirection_cameraspace; } Fragment shader: #version 130 // Interpolated values from the vertex shaders in vec2 UV; in vec3 Position_worldspace; in vec3 EyeDirection_cameraspace; in vec3 LightDirection_cameraspace; in vec3 LightDirection_tangentspace; in vec3 EyeDirection_tangentspace; // Ouput data out vec3 color; // Values that stay constant for the whole mesh. uniform sampler2D DiffuseTextureSampler; uniform sampler2D NormalTextureSampler; uniform sampler2D SpecularTextureSampler; uniform mat4 V; uniform mat4 M; uniform mat3 MV3x3; uniform vec3 LightPosition_worldspace; void main(){ // Light emission properties // You probably want to put them as uniforms vec3 LightColor = vec3(1,1,1); float LightPower = 40.0; // Material properties vec3 MaterialDiffuseColor = texture2D( DiffuseTextureSampler, vec2(UV.x,-UV.y) ).rgb; vec3 MaterialAmbientColor = vec3(0.1,0.1,0.1) * MaterialDiffuseColor; //vec3 MaterialSpecularColor = texture2D( SpecularTextureSampler, UV ).rgb * 0.3; vec3 MaterialSpecularColor = vec3(0.5,0.5,0.5); // Local normal, in tangent space. V tex coordinate is inverted because normal map is in TGA (not in DDS) for better quality vec3 TextureNormal_tangentspace = normalize(texture2D( NormalTextureSampler, vec2(UV.x,-UV.y) ).rgb*2.0 - 1.0); // Distance to the light float distance = length( LightPosition_worldspace - Position_worldspace ); // Normal of the computed fragment, in camera space vec3 n = TextureNormal_tangentspace; // Direction of the light (from the fragment to the light) vec3 l = normalize(LightDirection_tangentspace); // Cosine of the angle between the normal and the light direction, // clamped above 0 // - light is at the vertical of the triangle -> 1 // - light is perpendicular to the triangle -> 0 // - light is behind the triangle -> 0 float cosTheta = clamp( dot( n,l ), 0,1 ); // Eye vector (towards the camera) vec3 E = normalize(EyeDirection_tangentspace); // Direction in which the triangle reflects the light vec3 R = reflect(-l,n); // Cosine of the angle between the Eye vector and the Reflect vector, // clamped to 0 // - Looking into the reflection -> 1 // - Looking elsewhere -> < 1 float cosAlpha = clamp( dot( E,R ), 0,1 ); color = // Ambient : simulates indirect lighting MaterialAmbientColor + // Diffuse : "color" of the object MaterialDiffuseColor * LightColor * LightPower * cosTheta / (distance*distance) + // Specular : reflective highlight, like a mirror MaterialSpecularColor * LightColor * LightPower * pow(cosAlpha,5) / (distance*distance); //color.xyz = E; //color.xyz = LightDirection_tangentspace; //color.xyz = EyeDirection_tangentspace; } I have replaced the original color value by EyeDirection_tangentspace vector and then I got other strange effect but I can not link the image (not eunogh reputation) Is it possible that with this shaders is something wrong, or maybe in other place in my code e.g with my matrices? SOLVED Solved... 3 days needed for changing one letter from this: glBindBuffer(GL_ARRAY_BUFFER, vbo); glVertexAttribPointer ( 4, // attribute 3, // size GL_FLOAT, // type GL_FALSE, // normalized? sizeof(VboVertex), // stride (void*)(12*sizeof(float)) // array buffer offset ); to this: glBindBuffer(GL_ARRAY_BUFFER, vbo); glVertexAttribPointer ( 4, // attribute 3, // size GL_FLOAT, // type GL_FALSE, // normalized? sizeof(VboVertex), // stride (void*)(11*sizeof(float)) // array buffer offset ); see difference? :)

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• Annotation Processor for Superclass Sensitive Actions

  - by Geertjan

  Someone creating superclass sensitive actions should need to specify only the following things: The condition under which the popup menu item should be available, i.e., the condition under which the action is relevant. And, for superclass sensitive actions, the condition is the name of a superclass. I.e., if I'm creating an action that should only be invokable if the class implements "org.openide.windows.TopComponent",  then that fully qualified name is the condition. The position in the list of Java class popup menus where the new menu item should be found, relative to the existing menu items. The display name. The path to the action folder where the new action is registered in the Central Registry. The code that should be executed when the action is invoked. In other words, the code for the enablement (which, in this case, means the visibility of the popup menu item when you right-click on the Java class) should be handled generically, under the hood, and not every time all over again in each action that needs this special kind of enablement. So, here's the usage of my newly created @SuperclassBasedActionAnnotation, where you should note that the DataObject must be in the Lookup, since the action will only be available to be invoked when you right-click on a Java source file (i.e., text/x-java) in an explorer view: import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import org.netbeans.sbas.annotations.SuperclassBasedActionAnnotation; import org.openide.awt.StatusDisplayer; import org.openide.loaders.DataObject; import org.openide.util.NbBundle; import org.openide.util.Utilities; @SuperclassBasedActionAnnotation( position=30, displayName="#CTL_BrandTopComponentAction", path="File", type="org.openide.windows.TopComponent") @NbBundle.Messages("CTL_BrandTopComponentAction=Brand") public class BrandTopComponentAction implements ActionListener { private final DataObject context; public BrandTopComponentAction() { context = Utilities.actionsGlobalContext().lookup(DataObject.class); } @Override public void actionPerformed(ActionEvent ev) { String message = context.getPrimaryFile().getPath(); StatusDisplayer.getDefault().setStatusText(message); } } That implies I've created (in a separate module to where it is used) a new annotation. Here's the definition: package org.netbeans.sbas.annotations; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface SuperclassBasedActionAnnotation { String type(); String path(); int position(); String displayName(); } And here's the processor: package org.netbeans.sbas.annotations; import java.util.Set; import javax.annotation.processing.Processor; import javax.annotation.processing.RoundEnvironment; import javax.annotation.processing.SupportedAnnotationTypes; import javax.annotation.processing.SupportedSourceVersion; import javax.lang.model.SourceVersion; import javax.lang.model.element.Element; import javax.lang.model.element.TypeElement; import javax.lang.model.util.Elements; import org.openide.filesystems.annotations.LayerBuilder.File; import org.openide.filesystems.annotations.LayerGeneratingProcessor; import org.openide.filesystems.annotations.LayerGenerationException; import org.openide.util.lookup.ServiceProvider; @ServiceProvider(service = Processor.class) @SupportedAnnotationTypes("org.netbeans.sbas.annotations.SuperclassBasedActionAnnotation") @SupportedSourceVersion(SourceVersion.RELEASE_6) public class SuperclassBasedActionProcessor extends LayerGeneratingProcessor { @Override protected boolean handleProcess(Set annotations, RoundEnvironment roundEnv) throws LayerGenerationException { Elements elements = processingEnv.getElementUtils(); for (Element e : roundEnv.getElementsAnnotatedWith(SuperclassBasedActionAnnotation.class)) { TypeElement clazz = (TypeElement) e; SuperclassBasedActionAnnotation mpm = clazz.getAnnotation(SuperclassBasedActionAnnotation.class); String teName = elements.getBinaryName(clazz).toString(); String originalFile = "Actions/" + mpm.path() + "/" + teName.replace('.', '-') + ".instance"; File actionFile = layer(e).file( originalFile). bundlevalue("displayName", mpm.displayName()). methodvalue("instanceCreate", "org.netbeans.sbas.annotations.SuperclassSensitiveAction", "create"). stringvalue("type", mpm.type()). newvalue("delegate", teName); actionFile.write(); File javaPopupFile = layer(e).file( "Loaders/text/x-java/Actions/" + teName.replace('.', '-') + ".shadow"). stringvalue("originalFile", originalFile). intvalue("position", mpm.position()); javaPopupFile.write(); } return true; } } The "SuperclassSensitiveAction" referred to in the code above is unchanged from how I had it in yesterday's blog entry. When I build the module containing two action listeners that use my new annotation, the generated layer file looks as follows, which is identical to the layer file entries I hard coded yesterday: <folder name="Actions"> <folder name="File"> <file name="org-netbeans-sbas-impl-ActionListenerSensitiveAction.instance"> <attr name="displayName" stringvalue="Process Action Listener"/> <attr methodvalue="org.netbeans.sbas.annotations.SuperclassSensitiveAction.create" name="instanceCreate"/> <attr name="type" stringvalue="java.awt.event.ActionListener"/> <attr name="delegate" newvalue="org.netbeans.sbas.impl.ActionListenerSensitiveAction"/> </file> <file name="org-netbeans-sbas-impl-BrandTopComponentAction.instance"> <attr bundlevalue="org.netbeans.sbas.impl.Bundle#CTL_BrandTopComponentAction" name="displayName"/> <attr methodvalue="org.netbeans.sbas.annotations.SuperclassSensitiveAction.create" name="instanceCreate"/> <attr name="type" stringvalue="org.openide.windows.TopComponent"/> <attr name="delegate" newvalue="org.netbeans.sbas.impl.BrandTopComponentAction"/> </file> </folder> </folder> <folder name="Loaders"> <folder name="text"> <folder name="x-java"> <folder name="Actions"> <file name="org-netbeans-sbas-impl-ActionListenerSensitiveAction.shadow"> <attr name="originalFile" stringvalue="Actions/File/org-netbeans-sbas-impl-ActionListenerSensitiveAction.instance"/> <attr intvalue="10" name="position"/> </file> <file name="org-netbeans-sbas-impl-BrandTopComponentAction.shadow"> <attr name="originalFile" stringvalue="Actions/File/org-netbeans-sbas-impl-BrandTopComponentAction.instance"/> <attr intvalue="30" name="position"/> </file> </folder> </folder> </folder> </folder>

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• Combining Shared Secret and Certificates

  - by Michael Stephenson

  As discussed in the introduction article this walkthrough will explain how you can implement WCF security with the Windows Azure Service Bus to ensure that you can protect your endpoint in the cloud with a shared secret but also combine this with certificates so that you can identify the sender of the message.   Prerequisites As in the previous article before going into the walk through I want to explain a few assumptions about the scenario we are implementing but to keep the article shorter I am not going to walk through all of the steps in how to setup some of this. In the solution we have a simple console application which will represent the client application. There is also the services WCF application which contains the WCF service we will expose via the Windows Azure Service Bus. The WCF Service application in this example was hosted in IIS 7 on Windows 2008 R2 with AppFabric Server installed and configured to auto-start the WCF listening services. I am not going to go through significant detail around the IIS setup because it should not matter in relation to this article however if you want to understand more about how to configure WCF and IIS for such a scenario please refer to the following paper which goes into a lot of detail about how to configure this. The link is: http://tinyurl.com/8s5nwrz   Setting up the Certificates To keep the post and sample simple I am going to use the local computer store for all certificates but this bit is really just the same as setting up certificates for an example where you are using WCF without using Windows Azure Service Bus. In the sample I have included two batch files which you can use to create the sample certificates or remove them. Basically you will end up with: A certificate called PocServerCert in the personal store for the local computer which will be used by the WCF Service component A certificate called PocClientCert in the personal store for the local computer which will be used by the client application A root certificate in the Root store called PocRootCA with its associated revocation list which is the root from which the client and server certificates were created   For the sample Im just using development certificates like you would normally, and you can see exactly how these are configured and placed in the stores from the batch files in the solution using makecert and certmgr.   The Service Component To begin with let's look at the service component and how it can be configured to listen to the service bus using a shared secret but to also accept a username token from the client. In the sample the service component is called Acme.Azure.ServiceBus.Poc.Cert.Services. It has a single service which is the Visual Studio template for a WCF service when you add a new WCF Service Application so we have a service called Service1 with its Echo method. Nothing special so far!.... The next step is to look at the web.config file to see how we have configured the WCF service. In the services section of the WCF configuration you can see I have created my service and I have created a local endpoint which I simply used to do a little bit of diagnostics and to check it was working, but more importantly there is the Windows Azure endpoint which is using the ws2007HttpRelayBinding (note that this should also work just the same if your using netTcpRelayBinding). The key points to note on the above picture are the service behavior called MyServiceBehaviour and the service bus endpoints behavior called MyEndpointBehaviour. We will go into these in more detail later.   The Relay Binding The relay binding for the service has been configured to use the TransportWithMessageCredential security mode. This is the important bit where the transport security really relates to the interaction between the service and listening to the Azure Service Bus and the message credential is where we will use our certificate like we have specified in the message/clientCrentialType attribute. Note also that we have left the relayClientAuthenticationType set to RelayAccessToken. This means that authentication will be made against ACS for accessing the service bus and messages will not be accepted from any sender who has not been authenticated by ACS.   The Endpoint Behaviour In the below picture you can see the endpoint behavior which is configured to use the shared secret client credential for accessing the service bus and also for diagnostic purposes I have included the service registry element.     Hopefully if you are familiar with using Windows Azure Service Bus relay feature the above is very familiar to you and this is a very common setup for this section. There is nothing specific to the username token implementation here. The Service Behaviour Now we come to the bit with most of the certificate stuff in it. When you configure the service behavior I have included the serviceCredentials element and then setup to use the clientCertificate check and also specifying the serviceCertificate with information on how to find the servers certificate in the store.     I have also added a serviceAuthorization section where I will implement my own authorization component to perform additional security checks after the service has validated that the message was signed with a good certificate. I also have the same serviceSecurityAudit configuration to log access to my service. My Authorization Manager The below picture shows you implementation of my authorization manager. WCF will eventually hand off the message to my authorization component before it calls the service code. This is where I can perform some logic to check if the identity is allowed to access resources. In this case I am simple rejecting messages from anyone except the PocClientCertificate.     The Client Now let's take a look at the client side of this solution and how we can configure the client to authenticate against ACS but also send a certificate over to the service component so it can implement additional security checks on-premise. I have a console application and in the program class I want to use the proxy generated with Add Service Reference to send a message via the Azure Service Bus. You can see in my WCF client configuration below I have setup my details for the azure service bus url and am using the ws2007HttpRelayBinding.   Next is my configuration for the relay binding. You can see below I have configured security to use TransportWithMessageCredential so we will flow the token from a certificate with the message and also the RelayAccessToken relayClientAuthenticationType which means the component will validate against ACS before being allowed to access the relay endpoint to send a message.     After the binding we need to configure the endpoint behavior like in the below picture. This contains the normal transportClientEndpointBehaviour to setup the ACS shared secret configuration but we have also configured the clientCertificate to look for the PocClientCert.     Finally below we have the code of the client in the console application which will call the service bus. You can see that we have created our proxy and then made a normal call to a WCF in exactly the normal way but the configuration will jump in and ensure that a token is passed representing the client certificate.     Conclusion As you can see from the above walkthrough it is not too difficult to configure a service to use both a shared secret and certificate based token at the same time. This gives you the power and protection offered by the access control service in the cloud but also the ability to flow additional tokens to the on-premise component for additional security features to be implemented. Sample The sample used in this post is available at the following location: https://s3.amazonaws.com/CSCBlogSamples/Acme.Azure.ServiceBus.Poc.Cert.zip

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• MySQL Utility Users' Console Oerview

  - by rudrap

  MySQL Utility Users' Console (mysqluc): The MySQL Utilities Users' Console is designed to make using the utilities easier via a dedicated console. It helps us to use the utilities without worrying about the python and utility paths. Why do we need a special console? - It does provide a unique shell environment with command completion, help for each utility, user defined variables, and type completion for options. - You no longer have to type out the entire name of the utility. - You don't need to remember the name of a database utility you want to use. - You can define variables and reuse them in your utility commands. - It is possible to run utility command along with mysqluc and come out of the mysqluc console. Console commands: mysqluc> help Command Description ----------------------           --------------------------------------------------- help utilities                     Display list of all utilities supported. help <utility>                  Display help for a specific utility. help or help commands   Show this list. exit or quit                       Exit the console. set <variable>=<value>  Store a variable for recall in commands. show options                   Display list of options specified by the user on launch. show variables                 Display list of variables. <ENTER>                       Press ENTER to execute command. <ESCAPE>                     Press ESCAPE to clear the command entry. <DOWN>                       Press DOWN to retrieve the previous command. <UP>                               Press UP to retrieve the next command in history. <TAB>                            Press TAB for type completion of utility, option,or variable names. <TAB><TAB>                Press TAB twice for list of matching type completion (context sensitive). How do I use it? Pre-requisites: - Download the latest version of MySQL Workbench. - Mysql Servers are running. - Your Pythonpath is set. (e.g. Export PYTHONPATH=/...../mysql-utilities/) Check the Version of mysqluc Utility: /usr/bin/python mysqluc.py –version It should display something like this MySQL Utilities mysqluc.py version 1.1.0 - MySQL Workbench Distribution 5.2.44 Copyright (c) 2010, 2012 Oracle and/or its affiliates. All rights reserved. This program is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, to the extent permitted by law. Use of TAB to get the current utilities: mysqluc> mysqldb<TAB><TAB> Utility Description -------------        ------------------------------------------------------------ mysqldbcopy      copy databases from one server to another mysqldbexport    export metadata and data from databases mysqldbimport    import metadata and data from files mysqluc> mysqldbcopy –source=$se<TAB> Variable Value -------- ---------------------------------------------------------------------- server1 root@localhost:3306 server2 root@localhost:3307 you can see the variables starting with se and then decide which to use Run a utility via the console: /usr/bin/python mysqluc.py -e "mysqldbcopy --source=root@localhost:3306 --destination=root@localhost:3307 dbname" Get help for utilities in the console: mysqluc> help utilities Display help for a utility mysqluc> help mysqldbcopy Details about mysqldbcopy and its options set variables and use them in commands: mysqluc> set server1 = root@localhost:3306 mysqluc>show variables Variable Value -------- ---------------------------------------------------------------------- server1    root@localhost:3306 server2    root@localhost:3307 mysqluc> mysqldbcopy –source=$server1 –destination=$server2 dbname <Enter> Mysqldbcopy utility output will display. mysqluc>show options Display list of options specified by the user mysqluc SERVER=root@host123 VAR_A=57 -e "show variables" Variable Value -------- ----------------------------------------------------------------- SERVER root@host123 VAR_A 57 Finding option names for an Utility: mysqluc> mysqlserverclone --n Option Description ------------------- --------------------------------------------------------- --new-data=NEW_DATA the full path to the location of the data directory for the new instance --new-port=NEW_PORT the new port for the new instance - default=3307 --new-id=NEW_ID the server_id for the new instance - default=2 Limitations: User defined variables have a lifetime of the console run time.

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• UpdatePanel, JavaScript postback and changing querystring at same time in SharePoint Search Page

  - by Lee Dale

  Hi Guys, Been tearing my hear out with this one. Let me see if I can explain: I have a SharePoint results page on which I have a Search Results Core WebPart. Now I want to change the parameter in the querystring when I postback the page so that the WebPart returns different results for each parameter e.g. the querystring will be interactivemap.aspx?k=Country:Romania this will filter the results for Romania. First issue is I want to do this with javascript so I call: document.getElementById('aspnetForm').action = "interactivemap.aspx?k=Country:" + country; Nothing special here but the reason I need to call from Javascript is there is also a flash applet on this page from which the Javascript calls originate. When the javascript calls are made the page needs to PostBack but not reload the flash applet. I turned to ASP.Net AJAX for this so I wrapped the search results webpart in an update panel. Now if I use a button within the UpdatePanel to postback the UpdatePanel behaves as expected and does a partial render of the search results webpart not reloading the flash applet. Problem comes because I need postback the page from javscript. I called __doPostBack() as I have used this successully in the past. It works on it's own but fails when I first call the above Javascript before the __doPostBack() (I also tried calling click() on a hidden button) the code for the page is at the bottom. I think the problem comes with the scriptmanager not allowing a partial render when the form post action has changed. My questions are. A) Is there some other way to change the search results webpart parameter without using the querystring. or B) Is there a way around changing the querystring when doing an AJAX postback and getting a partial render. <asp:Content ContentPlaceHolderID="PlaceHolderFullContent" runat="server"> function update(country) { //__doPostBack('ContentUpdatePanel', ''); //document.getElementById('aspnetForm').action = "interactivemap.aspx?k=ArticleCountry:" + country; document.getElementById('ctl00_PlaceHolderFullContent_UpdateButton').click(); } Romania <div class="firstDataTitle"> <div class="datatabletitleOuterWrapper"> <div class="datatabletitle"> <span>Content</span></div> </div> <div class="datatableWrapper"> <div class="dataHolderWrapper"> <div class="datatable"> <div> <div class="searchMain"> <div class="searchZoneMain"> <asp:UpdatePanel runat="server" id="ContentUpdatePanel" UpdateMode="Conditional"> <ContentTemplate> <WebPartPages:webpartzone runat="server" AllowPersonalization="false" title="<%$Resources:sps,LayoutPageZone_BottomZone%>" id="BottomZone" orientation="Vertical" QuickAdd-GroupNames="Search" QuickAdd-ShowListsAndLibraries="false"><ZoneTemplate></ZoneTemplate></WebPartPages:webpartzone> <asp:Button id="UpdateButton" name="UpdateButton" runat="server" Text="Update"/> </ContentTemplate> </asp:UpdatePanel> </div> </div> </div> </div> </div> </div>

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• What is the reason of "Transaction context in use by another session"

  - by Shrike

  Hi, I'm looking for a description of the root of this error: "Transaction context in use by another session". I get it sometimes in one of my unittests so I can't provider repro code. But I wonder what is "by design" reason for the error. I've found this post: http://blogs.msdn.com/asiatech/archive/2009/08/10/system-transaction-may-fail-in-multiple-thread-environment.aspx and also that: http://msdn.microsoft.com/en-us/library/ff649002.aspx But I can't understand what "Multiple threads sharing the same transaction in a transaction scope will cause the following exception: 'Transaction context in use by another session.' " means. All words are understandable but not the point. I actually can share a system transaction between threads. And there is even special mechanism for this - DependentTransaction class and Transaction.DependentClone method. I'm trying to reproduce a usecase from the first post: 1. Main thread creates DTC transaction, receives DependentTransaction (created using Transaction.Current.DependentClone on the main thread 2. Child thread 1 enlists in this DTC transaction by creating a transaction scope based on the dependent transaction (passed via constructor) 3. Child thread 1 opens a connection 4. Child thread 2 enlists in DTC transaction by creating a transaction scope based on the dependent transaction (passed via constructor) 5. Child thread 2 opens a connection with such code: using System; using System.Threading; using System.Transactions; using System.Data; using System.Data.SqlClient; public class Program { private static string ConnectionString = "Initial Catalog=DB;Data Source=.;User ID=user;PWD=pwd;"; public static void Main() { int MAX = 100; for(int i =0; i< MAX;i++) { using(var ctx = new TransactionScope()) { var tx = Transaction.Current; // make the transaction distributed using (SqlConnection con1 = new SqlConnection(ConnectionString)) using (SqlConnection con2 = new SqlConnection(ConnectionString)) { con1.Open(); con2.Open(); } showSysTranStatus(); DependentTransaction dtx = Transaction.Current.DependentClone(DependentCloneOption.BlockCommitUntilComplete); Thread t1 = new Thread(o => workCallback(dtx)); Thread t2 = new Thread(o => workCallback(dtx)); t1.Start(); t2.Start(); t1.Join(); t2.Join(); ctx.Complete(); } trace("root transaction completes"); } } private static void workCallback(DependentTransaction dtx) { using(var txScope1 = new TransactionScope(dtx)) { using (SqlConnection con2 = new SqlConnection(ConnectionString)) { con2.Open(); trace("connection opened"); showDbTranStatus(con2); } txScope1.Complete(); } trace("dependant tran completes"); } private static void trace(string msg) { Console.WriteLine(Thread.CurrentThread.ManagedThreadId + " : " + msg); } private static void showSysTranStatus() { string msg; if (Transaction.Current != null) msg = Transaction.Current.TransactionInformation.DistributedIdentifier.ToString(); else msg = "no sys tran"; trace( msg ); } private static void showDbTranStatus(SqlConnection con) { var cmd = con.CreateCommand(); cmd.CommandText = "SELECT 1"; var c = cmd.ExecuteScalar(); trace("@@TRANCOUNT = " + c); } } It fails on Complete's call of root TransactionScope. But error is different: Unhandled Exception: System.Transactions.TransactionInDoubtException: The transaction is in doubt. --- pired. The timeout period elapsed prior to completion of the operation or the server is not responding. To sum up: I want to understand what "Transaction context in use by another session" means and how to reproduce it.

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• Act on click of a button on the Nav Bar for moreNavigationController -- Can't pushviewcontroller

  - by Jann

  Okay, here is my issue: My app has a display of categories in the tab bar at the bottom of the iPhoneOS screen. This only allows 5 categories before it presents the MORE button. I have over 25 (please do not answer this by saying: "Rethink your application...etc" -- that was rudely said before. They are food, drink, etc categories and cannot be changed). I want to allow the user to put their favorites on the home page. The Apple moreNavigationController editing system only allows 20 tab bar items to be rearranged due to space constraints on the editing page. This is not enough so i need to implement my own Editing screen. I set the rightBarButtonItem to nil and created my own. Using NSLog, i can see the "click" happens when clicking the EDIT button, but I cannot push using pushViewController. Nothing happens. I think it has something to do with the navigationController I am addressing...but i am not sure. ps: This all happens in my App Delegate which DOES act as both UITabBarControllerDelegate & UINavigationControllerDelegate. I tried to do the following: - ( void )navigationController:( UINavigationController * )navigationController_local willShowViewController:( UIViewController * )viewController_local animated:( BOOL )animated { UIViewController * currentController = navigationController_local.visibleViewController; UIViewController * nextController = viewController_local; // Do whatever here. NSLog(@"Nav contoller willShowViewController fired\n'%@'\n'%@'\nThere are currently: %d views on the stack\n",currentController,nextController,[self.navigationController.viewControllers count]); if ( [nextController isKindOfClass:NSClassFromString(@"UIMoreListController")]) { UINavigationBar *morenavbar = navigationController_local.navigationBar; UINavigationItem *morenavitem = morenavbar.topItem; morenavitem.rightBarButtonItem = nil; NSLog(@"Is a UIMoreListController\n"); UIBarButtonItem *editTabBarButton = [[UIBarButtonItem alloc] initWithTitle:@"Edit" style:UIBarButtonItemStylePlain target:self action:@selector(editTabBar:)]; morenavitem.rightBarButtonItem = editTabBarButton; [editTabBarButton release]; } } This works to place an EDIT button at the top right of the screen -- mimicking Apple's look and feel... but when that button is clicked, you cannot exit the darn moreNavigationController. I have tried many things. UIAlerts work, etc...but pushing (or popping -- even popping to root view) a view controller on the stack does not. - (void) editTabBar:(id)sender { NSLog(@"clicked edit tabbar\n"); NSLog(@"Total count of controllers: %d\n",[self.navigationController.viewControllers count]); TabBarViewController *tabBarViewController2 = [[TabBarViewController alloc] initWithNibName:@"TabBarView" bundle:nil]; tabBarViewController2.navigationItem.title=@"Edit Tab Bar"; [self.navigationController pushViewController:tabBarViewController2 animated:YES]; [tabBarViewController2 release]; NSLog(@"finished edit tabbar\n"); } If you click the edit button on the moreNavigationController's display page, you get the log entries like expected AND (this is strange) the views on the stack climbs -- but no page change occurs. I marked it down to not using the correct navigation controller...but I am lost on how to find which one TO use. this is a weird one too. In the edit function if i just do this: - (void) editTabBar:(id)sender { self.tabBarController.selectedIndex = 0; } It DOES take me home (to tabbarcontroller 0) BUT doing this: - (void) editTabBar:(id)sender { [self.navigationController popToRootViewControllerAnimated:YES]; } does not work. Does the moreNavigationController have some special quality that screws with the rest of the system?

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• Strange WCF Error - IIS hosted - context being aborted

  - by RandomNoob

  I have a WCF service that does some document conversions and returns the document to the caller. When developing locally on my local dev server, the service is hosted on ASP.NET Development server, a console application invokes the operation and executes within seconds. When I host the service in IIS via a .svc file, two of the documents work correctly, the third one bombs out, it begins to construct the word document using the OpenXml Sdk, but then just dies. I think this has something to do with IIS, but I cannot put my finger on it. There are a total of three types of documents I generate. In a nutshell this is how it works SQL 2005 DB/IBM DB2 - WCF Service written by other developer to expose data. This service only has one endpoint using basicHttpBinding My Service invokes his service, gets the relevant data, uses the Open Xml Sdk to generate a Microsoft Word Document, saves it on a server and returns the path to the user. The word documents are no bigger than 100KB. I am also using basicHttpBinding although I have tried wsHttpBinding with the same results. What is amazing is how fast it is locally, and even more that two of the documents generate just fine, its the third document type that refuses to work. To the error message: An error occured while receiving the HTTP Response to http://myservername.mydomain.inc/MyService/Service.Svc. This could be due to the service endpoint binding not using the HTTP Protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the server shutting down). See server logs for more details. I have spent the last 2 days trying to figure out what is going on, I have tried everything, including changing the maxReceivedMessageSize, maxBufferSize, maxBufferPoolSize, etc etc to large values, I even included: <httpRuntime maxRequestLength="2097151" executionTimeout="120"/> To see maybe if IIS was choking because of that. Programatically the service does nothing special, it just constructs the word documents from the data using the Open Xml Sdk and like I said, locally all 3 documents work when invoked via a console app running locally on the asp.net dev server, i.e. http://localhost:3332/myService.svc When I host it on IIS and I try to get a Windows Forms application to invoke it, I get the error. I know you will ask for logs, so yes I have logging enabled on my Host. And there is no error in the logs, I am logging everything. Basically I invoke two service operations written by another developer. MyOperation calls - HisOperation1 and then HisOperation2, both of those calls give me complex types. I am going to look at his code tomorrow, because he is using LINQ2SQL and there may be some funny business going on there. He is using a variety of collections etc, but the fact that I can run the exact same document, lets call it "Document 3" within seconds when the service is being hosted locally on ASP WebDev Server is what is most odd, why would it run on scaled down Cassini and blow up on IIS? From the log it seems, after calling HisOperation1 and HisOperation2 the service just goes into la-la land dies, there is a application pool (w3wp.exe) error in the Windows Event Log. Faulting application w3wp.exe, version 6.0.3790.1830, stamp 42435be1, faulting module kernel32.dll, version 5.2.3790.3311, stamp 49c5225e, debug? 0, fault address 0x00015dfa. It's classified as .NET 2.0 Runtime error. Any help is appreciated, the lack of sleep is getting to me. Help me Obi-Wan Kenobi, you're my only hope.

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• .NET 4.0 Dynamic object used statically?

  - by Kevin Won

  I've gotten quite sick of XML configuration files in .NET and want to replace them with a format that is more sane. Therefore, I'm writing a config file parser for C# applications that will take a custom config file format, parse it, and create a Python source string that I can then execute in C# and use as a static object (yes that's right--I want a static (not the static type dyanamic) object in the end). Here's an example of what my config file looks like: // my custom config file format GlobalName: ExampleApp Properties { ExternalServiceTimeout: "120" } Python { // this allows for straight python code to be added to handle custom config def MyCustomPython: return "cool" } Using ANTLR I've created a Lexer/Parser that will convert this format to a Python script. So assume I have that all right and can take the .config above and run my Lexer/Parser on it to get a Python script out the back (this has the added benefit of giving me a validation tool for my config). By running the resultant script in C# // simplified example of getting the dynamic python object in C# // (not how I really do it) ScriptRuntime py = Python.CreateRuntime(); dynamic conf = py.UseFile("conftest.py"); dynamic t = conf.GetConfTest("test"); I can get a dynamic object that has my configuration settings. I can now get my config file settings in C# by invoking a dynamic method on that object: //C# calling a method on the dynamic python object var timeout = t.GetProperty("ExternalServiceTimeout"); //the config also allows for straight Python scripting (via the Python block) var special = t.MyCustonPython(); of course, I have no type safety here and no intellisense support. I have a dynamic representation of my config file, but I want a static one. I know what my Python object's type is--it is actually newing up in instance of a C# class. But since it's happening in python, it's type is not the C# type, but dynamic instead. What I want to do is then cast the object back to the C# type that I know the object is: // doesn't work--can't cast a dynamic to a static type (nulls out) IConfigSettings staticTypeConfig = t as IConfigSettings Is there any way to figure out how to cast the object to the static type? I'm rather doubtful that there is... so doubtful that I took another approach of which I'm not entirely sure about. I'm wondering if someone has a better way... So here's my current tactic: since I know the type of the python object, I am creating a C# wrapper class: public class ConfigSettings : IConfigSettings that takes in a dynamic object in the ctor: public ConfigSettings(dynamic settings) { this.DynamicProxy = settings; } public dynamic DynamicProxy { get; private set; } Now I have a reference to the Python dynamic object of which I know the type. So I can then just put wrappers around the Python methods that I know are there: // wrapper access to the underlying dynamic object // this makes my dynamic object appear 'static' public string GetSetting(string key) { return this.DynamicProxy.GetProperty(key).ToString(); } Now the dynamic object is accessed through this static proxy and thus can obviously be passed around in the static C# world via interface, etc: // dependency inject the dynamic object around IBusinessLogic logic = new BusinessLogic(IConfigSettings config); This solution has the benefits of all the static typing stuff we know and love while at the same time giving me the option of 'bailing out' to dynamic too: // the DynamicProxy property give direct access to the dynamic object var result = config.DynamicProxy.MyCustomPython(); but, man, this seems rather convoluted way of getting to an object that is a static type in the first place! Since the whole dynamic/static interaction world is new to me, I'm really questioning if my solution is optimal or if I'm missing something (i.e. some way of casting that dynamic object to a known static type) about how to bridge the chasm between these two universes.

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• With Eclipselink/JPA, can I have a Foreign Composite Key that shares a field with a Primary Composit

  - by user107924

  My database has two entities; Company and Person. A Company can have many People, but a Person must have only one Company. The table structure looks as follows. COMPANY ---------- owner PK comp_id PK c_name PERSON ---------------- owner PK, FK1 personid PK comp_id FK1 p_fname p_sname It has occurred to me that I could remove PERSON.OWNER and derive it through the foreign key; however, I can't make this change without affecting legacy code. I have modeled these as JPA-annotated classes; @Entity @Table(name = "PERSON") @IdClass(PersonPK.class) public class Person implements Serializable { @Id private String owner; @Id private String personid; @ManyToOne @JoinColumns( {@JoinColumn(name = "owner", referencedColumnName = "OWNER", insertable = false, updatable = false), @JoinColumn(name = "comp_id", referencedColumnName = "COMP_ID", insertable = true, updatable = true)}) private Company company; private String p_fname; private String p_sname; ...and standard getters/setters... } @Entity @Table(name = "COMPANY") @IdClass(CompanyPK.class) public class Company implements Serializable { @Id private String owner; @Id private String comp_id; private String c_name; @OneToMany(mappedBy = "company", cascade=CascadeType.ALL) private List people; ...and standard getters/setters... } My PersonPK and CompanyPK classes are nothing special, they just serve as a struct holding owner and the ID field, and override hashCode and equals(o). So far so good. I come across a problem, however, when trying to deal with associations. It seems if I have an existing Company, and create a Person, and associate to the Person to the Company and persist the company, the association is not saved when the Person is inserted. For example, my main code looks like this: EntityManager em = emf.createEntityManager(); em.getTransaction().begin(); CompanyPK companyPK = new CompanyPK(); companyPK.owner="USA"; companyPK.comp_id="1102F3"; Company company = em.find(Company.class, companyPK); Person person = new Person(); person.setOwner("USA"); person.setPersonid("5116628123"); //some number that doesn't exist yet person.setP_fname("Hannah"); person.setP_sname("Montana"); person.setCompany(company); em.persist(person); This completes without error; however in the database I find that the Person record was inserted with a null in the COMP_ID field. With EclipseLink debug logging set to FINE, the SQL query is shown as: INSERT INTO PERSON (PERSONID,OWNER,P_SNAME,P_FNAME) VALUES (?,?,?,?) bind = [5116628123,USA,Montana,Hannah,] I would have expected this to be saved, and the query to be equivalent to INSERT INTO PERSON (PERSONID,OWNER,COMP_ID,P_SNAME,P_FNAME) VALUES (?,?,?,?,?) bind = [5116628123,USA,1102F3,Montana,Hannah,] What gives? Is it incorrect to say updatable/insertable=true for one half of a composite key and =false for the other half? If I have updatable/insertable=true for both parts of the foreign key, then Eclipselink fails to startup saying that I can not use the column twice without having one set to readonly by specifying these options.

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• How to animate an non-closed path with CAShapeLayer?

  - by mystify

  On GitHub you can find an example for CAShapeLayer which animates an path. It animates a pentagon turning into a star. First: This works only in the iPhone simulator. OS 3.0 on the device shows serious bugs with this code. But I can't find anything wrong in there. However, I tried to animate an path which is not closed. To put it simply: A few straight lines. Is there anything special I must do to get this work properly on the device? - (void)loadView { UIView *appView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; appView.backgroundColor = [UIColor blackColor]; self.view = appView; [appView release]; rootLayer = [CALayer layer]; rootLayer.frame = self.view.bounds; [self.view.layer addSublayer:rootLayer]; //Pentagon Path pentagonPath = CGPathCreateMutable(); CGPathMoveToPoint(pentagonPath, nil, 10.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 100.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 110.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 120.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 130.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 310.0f, 270.0f); //CGPathCloseSubpath(pentagonPath); //Star Path starPath = CGPathCreateMutable(); CGPathMoveToPoint(starPath, nil, 10.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 100.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 210.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 220.0f, 260.0f); CGPathAddLineToPoint(starPath, nil, 230.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 310.0f, 270.0f); //CGPathCloseSubpath(starPath); //Create Shape shapeLayer = [CAShapeLayer layer]; //shapeLayer.path = pentagonPath; UIColor *col = [UIColor colorWithWhite:0.9 alpha:1.0]; //shapeLayer.fillColor = col.CGColor; shapeLayer.strokeColor = col.CGColor; shapeLayer.lineWidth = 3.0f; // shapeLayer.contents = [UIImage imageNamed:@"test.png"]; shapeLayer.fillRule = kCAFillRuleEvenOdd; [rootLayer addSublayer:shapeLayer]; [self performSelector:@selector(startAnimation) withObject:nil afterDelay:1.0]; } -(void)startAnimation { CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"]; animation.duration = 2.0; animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; animation.repeatCount = 1e100f; animation.autoreverses = YES; animation.fromValue = (id)pentagonPath; animation.toValue = (id)starPath; [shapeLayer addAnimation:animation forKey:@"animatePath"]; } Note this lines, where I just make straight lines with a small peak which is animated: //Pentagon Path pentagonPath = CGPathCreateMutable(); CGPathMoveToPoint(pentagonPath, nil, 10.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 100.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 110.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 120.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 130.0f, 270.0f); CGPathAddLineToPoint(pentagonPath, nil, 310.0f, 270.0f); //CGPathCloseSubpath(pentagonPath); //Star Path starPath = CGPathCreateMutable(); CGPathMoveToPoint(starPath, nil, 10.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 100.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 210.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 220.0f, 260.0f); CGPathAddLineToPoint(starPath, nil, 230.0f, 270.0f); CGPathAddLineToPoint(starPath, nil, 310.0f, 270.0f); I don't want a closed and filled path, but only simple lines with some color and thickness. The nasty thing on the device is, that the first point seems to move towards the right side of the screen for no reason. On the simulator though, it works perfectly fine. Maybe something is wrong with this setup?

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• Should we hire someone who writes C in Perl?

  - by paxdiablo

  One of my colleagues recently interviewed some candidates for a job and one said they had very good Perl experience. Since my colleague didn't know Perl, he asked me for a critique of some code written (off-site) by that potential hire, so I had a look and told him my concerns (the main one was that it originally had no comments and it's not like we gave them enough time). However, the code works so I'm loathe to say no-go without some more input. Another concern is that this code basically looks exactly how I'd code it in C. It's been a while since I did Perl (and I didn't do a lot, I'm more a Python bod for quick scripts) but I seem to recall that it was a much more expressive language than what this guy used. I'm looking for input from real Perl coders, and suggestions for how it could be improved (and why a Perl coder should know that method of improvement). You can also wax lyrical about whether people who write one language in a totally different language should (or shouldn't be hired). I'm interested in your arguments but this question is primarily for a critique of the code. The spec was to successfully process a CSV file as follows and output the individual fields: User ID,Name , Level,Numeric ID pax, Pax Morgan ,admin,0 gt," Turner, George" rubbish,user,1 ms,"Mark \"X-Men\" Spencer","guest user",2 ab,, "user","3" The output was to be something like this (the potential hire's code actually output this): User ID,Name , Level,Numeric ID: [User ID] [Name] [Level] [Numeric ID] pax, Pax Morgan ,admin,0: [pax] [Pax Morgan] [admin] [0] gt," Turner, George " rubbish,user,1: [gt] [ Turner, George ] [user] [1] ms,"Mark \"X-Men\" Spencer","guest user",2: [ms] [Mark "X-Men" Spencer] [guest user] [2] ab,, "user","3": [ab] [] [user] [3] Here is the code they submitted: #!/usr/bin/perl # Open file. open (IN, "qq.in") || die "Cannot open qq.in"; # Process every line. while (<IN>) { chomp; $line = $_; print "$line:\n"; # Process every field in line. while ($line ne "") { # Skip spaces and start with empty field. if (substr ($line,0,1) eq " ") { $line = substr ($line,1); next; } $field = ""; $minlen = 0; # Detect quoted field or otherwise. if (substr ($line,0,1) eq "\"") { $line = substr ($line,1); $pastquote = 0; while ($line ne "") { # Special handling for quotes (\\ and \"). if (length ($line) >= 2) { if (substr ($line,0,2) eq "\\\"") { $field = $field . "\""; $line = substr ($line,2); next; } if (substr ($line,0,2) eq "\\\\") { $field = $field . "\\"; $line = substr ($line,2); next; } } # Detect closing quote. if (($pastquote == 0) && (substr ($line,0,1) eq "\"")) { $pastquote = 1; $line = substr ($line,1); $minlen = length ($field); next; } # Only worry about comma if past closing quote. if (($pastquote == 1) && (substr ($line,0,1) eq ",")) { $line = substr ($line,1); last; } $field = $field . substr ($line,0,1); $line = substr ($line,1); } } else { while ($line ne "") { if (substr ($line,0,1) eq ",") { $line = substr ($line,1); last; } if ($pastquote == 0) { $field = $field . substr ($line,0,1); } $line = substr ($line,1); } } # Strip trailing space. while ($field ne "") { if (length ($field) == $minlen) { last; } if (substr ($field,length ($field)-1,1) eq " ") { $field = substr ($field,0, length ($field)-1); next; } last; } print " [$field]\n"; } } close (IN);

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• Taking screenshots in Windows Vista, Windows 7, with transparent areas outside the app region

  - by Steve Sheldon

  Hey Folks, I am trying to take a screenshot of an application and I would like to make the parts of the rectangle that are not part of the applications region be transparent. So for instance on a standard windows application I would like to make the rounded corners transparent. I wrote a quick test application which works on on XP (or vista/windows 7 with aero turned off): protected override void OnPaint(PaintEventArgs e) { base.OnPaint(e); Graphics g = e.Graphics; // Just find a window to test with IntPtr hwnd = FindWindowByCaption(IntPtr.Zero, "Calculator"); WINDOWINFO info = new WINDOWINFO(); info.cbSize = (uint)Marshal.SizeOf(info); GetWindowInfo(hwnd, ref info); Rectangle r = Rectangle.FromLTRB(info.rcWindow.Left, info.rcWindow.Top, info.rcWindow.Right, info.rcWindow.Bottom); IntPtr hrgn = CreateRectRgn(info.rcWindow.Left, info.rcWindow.Top, info.rcWindow.Right, info.rcWindow.Bottom); GetWindowRgn(hwnd, hrgn); // fill a rectangle which would be where I would probably // write some mask color g.FillRectangle(Brushes.Red, r); // fill the region over the top, all I am trying to do here // is show the contrast between the applications region and // the rectangle that the region would be placed in Region region = Region.FromHrgn(hrgn); region.Translate(info.rcWindow.Left, info.rcWindow.Top); g.FillRegion(Brushes.Blue, region); } Quick side note: before commenting that this code is doing stuff it shouldn't (or should do, like dispose) in a paint function, I know, it's not going anywhere but this post and is designed purely as a way to quickly show the problem, and that it does... OK, back to the problem ;) When I run this test app on XP (or Vista/Windows 7 with Aero off), I get something like this, which is great because I can eek an xor mask out of this that can be used later with BitBlt. Here is the problem, on Vista or Windows 7 with Aero enabled, there isn't necessarily a region on the window, in fact in most cases there isn't. Can anybody help me figure out how to get the region of the application like this on these platforms. Here are some of the approaches I have already tried... 1. Using the PrintWindow function: This doesn't work because it gives back a screenshot taken of the window with Aero off and this window is a different shape from the window returned with Aero on 2 Using the Desktop Window Manager API to get a full size thumbnail: This didn't work because it draws directly to the screen and from what I can tell you can't get a screenshot directly out of this api. Yeah, I could open a window with a pink background, show the thumbnail, take a screenshot then hide this temporary window but thats a horrible user experience and a complete hack I would rather not have my name on. 3. Using Graphics.CopyFromScreen or some other pinvoke variant of this: This doesn't work because I can't assume that the window I need information from is at the top of the z-order on the screen. Right now, the best solution I can think of is to special case Aero on Windows 7 and Vista to manually rub out the corners by hard coding some graphics paths I paint out but this solution would suck since any application that performs custom skinning will break this. Can you think of another or better solution? If you are here, thanks for taking time to read this post, I appreciate any help or direction that you can offer!

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• Xcode newb -- #include can't find my file

  - by morgancodes

  I'm trying to get a third party audio library (STK) working inside Xcode. Along with the standard .h files, many of the implementation files include a file called SKINI.msg. SKINI.msg is in the same directory as all of the header files. The header files are getting included fine, but the compiler complains that it can't find SKINI.msg. What do I need to do to get Xcode to happily include SKINI.msg? Edit: Here's the contents of SKINI.msg: /*********************************************************/ /* Definition of SKINI Message Types and Special Symbols Synthesis toolKit Instrument Network Interface These symbols should have the form: \c __SK_<name>_ where <name> is the string used in the SKINI stream. by Perry R. Cook, 1995 - 2010. */ /*********************************************************/ namespace stk { #define NOPE -32767 #define YEP 1 #define SK_DBL -32766 #define SK_INT -32765 #define SK_STR -32764 #define __SK_Exit_ 999 /***** MIDI COMPATIBLE MESSAGES *****/ /*** (Status bytes for channel=0) ***/ #define __SK_NoteOff_ 128 #define __SK_NoteOn_ 144 #define __SK_PolyPressure_ 160 #define __SK_ControlChange_ 176 #define __SK_ProgramChange_ 192 #define __SK_AfterTouch_ 208 #define __SK_ChannelPressure_ __SK_AfterTouch_ #define __SK_PitchWheel_ 224 #define __SK_PitchBend_ __SK_PitchWheel_ #define __SK_PitchChange_ 49 #define __SK_Clock_ 248 #define __SK_SongStart_ 250 #define __SK_Continue_ 251 #define __SK_SongStop_ 252 #define __SK_ActiveSensing_ 254 #define __SK_SystemReset_ 255 #define __SK_Volume_ 7 #define __SK_ModWheel_ 1 #define __SK_Modulation_ __SK_ModWheel_ #define __SK_Breath_ 2 #define __SK_FootControl_ 4 #define __SK_Portamento_ 65 #define __SK_Balance_ 8 #define __SK_Pan_ 10 #define __SK_Sustain_ 64 #define __SK_Damper_ __SK_Sustain_ #define __SK_Expression_ 11 #define __SK_AfterTouch_Cont_ 128 #define __SK_ModFrequency_ __SK_Expression_ #define __SK_ProphesyRibbon_ 16 #define __SK_ProphesyWheelUp_ 2 #define __SK_ProphesyWheelDown_ 3 #define __SK_ProphesyPedal_ 18 #define __SK_ProphesyKnob1_ 21 #define __SK_ProphesyKnob2_ 22 /*** Instrument Family Specific ***/ #define __SK_NoiseLevel_ __SK_FootControl_ #define __SK_PickPosition_ __SK_FootControl_ #define __SK_StringDamping_ __SK_Expression_ #define __SK_StringDetune_ __SK_ModWheel_ #define __SK_BodySize_ __SK_Breath_ #define __SK_BowPressure_ __SK_Breath_ #define __SK_BowPosition_ __SK_PickPosition_ #define __SK_BowBeta_ __SK_BowPosition_ #define __SK_ReedStiffness_ __SK_Breath_ #define __SK_ReedRestPos_ __SK_FootControl_ #define __SK_FluteEmbouchure_ __SK_Breath_ #define __SK_JetDelay_ __SK_FluteEmbouchure_ #define __SK_LipTension_ __SK_Breath_ #define __SK_SlideLength_ __SK_FootControl_ #define __SK_StrikePosition_ __SK_PickPosition_ #define __SK_StickHardness_ __SK_Breath_ #define __SK_TrillDepth_ 1051 #define __SK_TrillSpeed_ 1052 #define __SK_StrumSpeed_ __SK_TrillSpeed_ #define __SK_RollSpeed_ __SK_TrillSpeed_ #define __SK_FilterQ_ __SK_Breath_ #define __SK_FilterFreq_ 1062 #define __SK_FilterSweepRate_ __SK_FootControl_ #define __SK_ShakerInst_ 1071 #define __SK_ShakerEnergy_ __SK_Breath_ #define __SK_ShakerDamping_ __SK_ModFrequency_ #define __SK_ShakerNumObjects_ __SK_FootControl_ #define __SK_Strumming_ 1090 #define __SK_NotStrumming_ 1091 #define __SK_Trilling_ 1092 #define __SK_NotTrilling_ 1093 #define __SK_Rolling_ __SK_Strumming_ #define __SK_NotRolling_ __SK_NotStrumming_ #define __SK_PlayerSkill_ 2001 #define __SK_Chord_ 2002 #define __SK_ChordOff_ 2003 #define __SK_SINGER_FilePath_ 3000 #define __SK_SINGER_Frequency_ 3001 #define __SK_SINGER_NoteName_ 3002 #define __SK_SINGER_Shape_ 3003 #define __SK_SINGER_Glot_ 3004 #define __SK_SINGER_VoicedUnVoiced_ 3005 #define __SK_SINGER_Synthesize_ 3006 #define __SK_SINGER_Silence_ 3007 #define __SK_SINGER_VibratoAmt_ __SK_ModWheel_ #define __SK_SINGER_RndVibAmt_ 3008 #define __SK_SINGER_VibFreq_ __SK_Expression_ } // stk namespace And here's what the compiler said: CompileC build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/Objects-normal/i386/BandedWG.o "../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp" normal i386 c++ com.apple.compilers.gcc.4_2 cd /Users/morganpackard/Desktop/trashme/StkCompile setenv LANG en_US.US-ASCII setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin" /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 -x c++ -arch i386 -fmessage-length=0 -pipe -Wno-trigraphs -fpascal-strings -fasm-blocks -O0 -Wreturn-type -Wunused-variable -D__IPHONE_OS_VERSION_MIN_REQUIRED=30000 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.2.sdk -fvisibility=hidden -fvisibility-inlines-hidden -mmacosx-version-min=10.5 -gdwarf-2 -iquote /Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-generated-files.hmap -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-own-target-headers.hmap -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-all-target-headers.hmap -iquote /Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-project-headers.hmap -F/Users/morganpackard/Desktop/trashme/StkCompile/build/Debug-iphonesimulator -I/Users/morganpackard/Desktop/trashme/StkCompile/build/Debug-iphonesimulator/include -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/DerivedSources/i386 -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/DerivedSources -include /var/folders/dx/dxSUSyOJFv0MBEh9qC1oJ++++TI/-Caches-/com.apple.Xcode.501/SharedPrecompiledHeaders/StkCompile_Prefix-bopqzvwpuyqltrdumgtjtfrjvtzb/StkCompile_Prefix.pch -c "/Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp" -o /Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/Objects-normal/i386/BandedWG.o /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:33:21: error: SKINI.msg: No such file or directory /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp: In member function 'virtual void stk::BandedWG::controlChange(int, stk::StkFloat)': /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:326: error: '__SK_BowPressure_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:342: error: '__SK_AfterTouch_Cont_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:349: error: '__SK_ModWheel_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:357: error: '__SK_ModFrequency_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:359: error: '__SK_Sustain_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:363: error: '__SK_Portamento_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:367: error: '__SK_ProphesyRibbon_' was not declared in this scope

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• How to use pthread_atfork() and pthread_once() to reinitialize mutexes in child processes

  - by Blair Zajac

  We have a C++ shared library that uses ZeroC's Ice library for RPC and unless we shut down Ice's runtime, we've observed child processes hanging on random mutexes. The Ice runtime starts threads, has many internal mutexes and keeps open file descriptors to servers. Additionally, we have a few of mutexes of our own to protect our internal state. Our shared library is used by hundreds of internal applications so we don't have control over when the process calls fork(), so we need a way to safely shutdown Ice and lock our mutexes while the process forks. Reading the POSIX standard on pthread_atfork() on handling mutexes and internal state: Alternatively, some libraries might have been able to supply just a child routine that reinitializes the mutexes in the library and all associated states to some known value (for example, what it was when the image was originally executed). This approach is not possible, though, because implementations are allowed to fail *_init() and *_destroy() calls for mutexes and locks if the mutex or lock is still locked. In this case, the child routine is not able to reinitialize the mutexes and locks. On Linux, the this test C program returns EPERM from pthread_mutex_unlock() in the child pthread_atfork() handler. Linux requires adding _NP to the PTHREAD_MUTEX_ERRORCHECK macro for it to compile. This program is linked from this good thread. Given that it's technically not safe or legal to unlock or destroy a mutex in the child, I'm thinking it's better to have pointers to mutexes and then have the child make new pthread_mutex_t on the heap and leave the parent's mutexes alone, thereby having a small memory leak. The only issue is how to reinitialize the state of the library and I'm thinking of reseting a pthread_once_t. Maybe because POSIX has an initializer for pthread_once_t that it can be reset to its initial state. #include <pthread.h> #include <stdlib.h> #include <string.h> static pthread_once_t once_control = PTHREAD_ONCE_INIT; static pthread_mutex_t *mutex_ptr = 0; static void setup_new_mutex() { mutex_ptr = malloc(sizeof(*mutex_ptr)); pthread_mutex_init(mutex_ptr, 0); } static void prepare() { pthread_mutex_lock(mutex_ptr); } static void parent() { pthread_mutex_unlock(mutex_ptr); } static void child() { // Reset the once control. pthread_once_t once = PTHREAD_ONCE_INIT; memcpy(&once_control, &once, sizeof(once_control)); setup_new_mutex(); } static void init() { setup_new_mutex(); pthread_atfork(&prepare, &parent, &child); } int my_library_call(int arg) { pthread_once(&once_control, &init); pthread_mutex_lock(mutex_ptr); // Do something here that requires the lock. int result = 2*arg; pthread_mutex_unlock(mutex_ptr); return result; } In the above sample in the child() I only reset the pthread_once_t by making a copy of a fresh pthread_once_t initialized with PTHREAD_ONCE_INIT. A new pthread_mutex_t is only created when the library function is invoked in the child process. This is hacky but maybe the best way of dealing with this skirting the standards. If the pthread_once_t contains a mutex then the system must have a way of initializing it from its PTHREAD_ONCE_INIT state. If it contains a pointer to a mutex allocated on the heap than it'll be forced to allocate a new one and set the address in the pthread_once_t. I'm hoping it doesn't use the address of the pthread_once_t for anything special which would defeat this. Searching comp.programming.threads group for pthread_atfork() shows a lot of good discussion and how little the POSIX standards really provides to solve this problem. There's also the issue that one should only call async-signal-safe functions from pthread_atfork() handlers, and it appears the most important one is the child handler, where only a memcpy() is done. Does this work? Is there a better way of dealing with the requirements of our shared library?

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• Receicing POST data in ASP.NET

  - by grast

  Hi, I want to use ASP for code generation in a C# desktop application. To achieve this, I set up a simple host (derived from System.MarshalByRefObject) that processes a System.Web.Hosting.SimpleWorkerRequest via HttpRuntime.ProcessRequest. This processes the ASPX script specified by the incoming request (using System.Net.HttpListener to wait for requests). The client-part is represented by a System.ComponentModel.BackgroundWorker that builds the System.Net.HttpWebRequest and receives the response from the server. A simplified version of my client-part-code looks like this: private void SendRequest(object sender, DoWorkEventArgs e) { // create request with GET parameter var uri = "http://localhost:9876/test.aspx?getTest=321"; var request = (HttpWebRequest)WebRequest.Create(uri); // append POST parameter request.Method = "POST"; request.ContentType = "application/x-www-form-urlencoded"; var postData = Encoding.Default.GetBytes("postTest=654"); var postDataStream = request.GetRequestStream(); postDataStream.Write(postData, 0, postData.Length); // send request, wait for response and store/print content using (var response = (HttpWebResponse)request.GetResponse()) { using (var reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8)) { _processsedContent = reader.ReadToEnd(); Debug.Print(_processsedContent); } } } My server-part-code looks like this (without exception-handling etc.): public void ProcessRequests() { // HttpListener at http://localhost:9876/ var listener = SetupListener(); // SimpleHost created by ApplicationHost.CreateApplicationHost var host = SetupHost(); while (_running) { var context = listener.GetContext(); using (var writer = new StreamWriter(context.Response.OutputStream)) { // process ASP script and send response back to client host.ProcessRequest(GetPage(context), GetQuery(context), writer); } context.Response.Close(); } } So far all this works fine as long as I just use GET parameters. But when it comes to receiving POST data in my ASPX script I run into trouble. For testing I use the following script: // GET parameters are working: var getTest = Request.QueryString["getTest"]; Response.Write("getTest: " + getTest); // prints "getTest: 321" // don't know how to access POST parameters: var postTest1 = Request.Form["postTest"]; // Request.Form is empty?! Response.Write("postTest1: " + postTest1); // so this prints "postTest1: " var postTest2 = Request.Params["postTest"]; // Request.Params is empty?! Response.Write("postTest2: " + postTest2); // so this prints "postTest2: " It seems that the System.Web.HttpRequest object I'm dealing with in ASP does not contain any information about my POST parameter "postTest". I inspected it in debug mode and none of the members did contain neither the parameter-name "postTest" nor the parameter-value "654". I also tried the BinaryRead method of Request, but unfortunately it is empty. This corresponds to Request.InputStream==null and Request.ContentLength==0. And to make things really confusing the Request.HttpMethod member is set to "GET"?! To isolate the problem I tested the code by using a PHP script instead of the ASPX script. This is very simple: print_r($_GET); // prints all GET variables print_r($_POST); // prints all POST variables And the result is: Array ( [getTest] = 321 ) Array ( [postTest] = 654 ) So with the PHP script it works, I can access the POST data. Why does the ASPX script don't? What am I doing wrong? Is there a special accessor or method in the Response object? Can anyone give a hint or even know how to solve this? Thanks in advance.

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• CD/DVD burn error in ImgBurn and Nero

  - by bobby

  I am getting the errors shown below when I try to burn a CD/DVD on my DVD writer. I am seeing this error for every CD/DVD I try to burn. I am not able to write any CDs or DVDs using ImgBurn. The burn log below is a failed burn in Nero. What could be causing this error? Nero Burning ROM bobby 4C85-200E-4005-0004-0000-7660-0800-35X3-0000-407M-MX37-**** (*) Windows XP 6.1 IA32 WinAspi: - NT-SPTI used Nero Version: 7.11.3. Internal Version: 7, 11, 3, (Nero Express) Recorder: <HL-DT-ST DVDRAM GSA-H12N> Version: UL01 - HA 1 TA 1 - 7.11.3.0 Adapter driver: <IDE> HA 1 Drive buffer : 2048kB Bus Type : default CD-ROM: <ATAPI-CD ROM-DRIVE-52MAX > Version: 52PP - HA 1 TA 0 - 7.11.3.0 Adapter driver: <IDE> HA 1 === Scsi-Device-Map === === CDRom-Device-Map === ATAPI-CD ROM-DRIVE-52MAX F: CdRom0 HL-DT-ST DVDRAM GSA-H12N G: CdRom1 ======================= AutoRun : 1 Excluded drive IDs: WriteBufferSize: 83886080 (0) Byte BUFE : 0 Physical memory : 958MB (981560kB) Free physical memory: 309MB (317024kB) Memory in use : 67 % Uncached PFiles: 0x0 Use Inquiry : 1 Global Bus Type: default (0) Check supported media : Disabled (0) 11.6.2010 CD Image 10:43:02 AM #1 Text 0 File SCSIPTICommands.cpp, Line 450 LockMCN - completed sucessfully for IOCTL_STORAGE_MCN_CONTROL 10:43:02 AM #2 Text 0 File Burncd.cpp, Line 3186 HL-DT-ST DVDRAM GSA-H12N Buffer underrun protection activated 10:43:02 AM #3 Text 0 File Burncd.cpp, Line 3500 Turn on Disc-At-Once, using CD-R/RW media 10:43:02 AM #4 Text 0 File DlgWaitCD.cpp, Line 307 Last possible write address on media: 359848 ( 79:59.73) Last address to be written: 318783 ( 70:52.33) 10:43:02 AM #5 Text 0 File DlgWaitCD.cpp, Line 319 Write in overburning mode: NO (enabled: CD) 10:43:02 AM #6 Text 0 File DlgWaitCD.cpp, Line 2988 Recorder: HL-DT-ST DVDRAM G SA-H12N; CDR co de: 00 97 27 18; O SJ entry from: Pla smon Data systems Ltd. ATIP Data: Special Info [hex] 1: D0 00 A0, 2: 61 1B 12 (LI 97:27.18), 3: 4F 3B 4A ( LO 79:59.74) Additional Info [hex] 1: 00 00 00 (invalid), 2: 00 00 00 (invalid), 3: 00 0 0 00 (invalid) 10:43:02 AM #7 Text 0 File DlgWaitCD.cpp, Line 493 >>> Protocol of DlgWaitCD activities: <<< ========================================= 10:43:02 AM #8 Text 0 File ThreadedTransferInterface.cpp, Line 785 Nero Report 1 Nero Burning ROM Setup items (after recorder preparation) 0: TRM_DATA_MODE1 (2 - CD-ROM Mode 1, Joliet) 2 indices, index0 (150) not provided original disc pos #0 + 318784 (318784) = #318784/70:50.34 not relocatable, disc pos for caching/writing not required/not required -> TRM_DATA_MODE1, 2048, config 0, wanted index0 0 blocks, length 318784 blocks [G: HL-DT-ST DVDRAM GSA-H12N] -------------------------------------------------------------- 10:43:02 AM #9 Text 0 File ThreadedTransferInterface.cpp, Line 986 Prepare [G: HL-DT-ST DVDRAM GSA-H12N] for write in CUE-sheet-DAO DAO infos: ========== MCN: "" TOCType: 0x00; Se ssion Clo sed, disc fixated Tracks 1 to 1: Idx 0 Idx 1 Next T rk 1: TRM_DATA_MODE1, 2048/0x00, FilePos 0 307200 6531768 32, ISRC "" DAO layout: =========== ___Start_|____Track_|_Idx_|_CtrlAdr_|_____Size_|______NWA_|_RecDep__________ -150 | lead-in | 0 | 0x41 | 0 | 0 | 0x00 -150 | 1 | 0 | 0x41 | 0 | 0 | 0x00 0 | 1 | 1 | 0x41 | 318784 | 318784 | 0x00 318784 | lead-out | 1 | 0x41 | 0 | 0 | 0x00 10:43:02 AM #10 Text 0 File SCSIPTICommands.cpp, Line 240 SPTILockVolume - completed successfully for FSCTL_LOCK_VOLUME 10:43:02 AM #11 Text 0 File Burncd.cpp, Line 4286 Caching options: cache CDRom or Network-Yes, small files-Yes (<64KB) 10:43:02 AM #12 Phase 24 File dlgbrnst.cpp, Line 1767 Caching of files started 10:43:02 AM #13 Text 0 File Burncd.cpp, Line 4405 Cache writing successful. 10:43:02 AM #14 Phase 25 File dlgbrnst.cpp, Line 1767 Caching of files completed 10:43:02 AM #15 Phase 36 File dlgbrnst.cpp, Line 1767 Burn process started at 48x (7,200 KB/s) 10:43:02 AM #16 Text 0 File ThreadedTransferInterface.cpp, Line 2733 Verifying disc position of item 0 (not relocatable, no disc pos, no patch infos, orig at #0): write at #0 10:43:02 AM #17 Text 0 File MMC.cpp, Line 17806 StartDAO : CD-Text - Off 10:43:02 AM #18 Text 0 File MMC.cpp, Line 22488 Set BUFE: Buffer underrun protection -> ON 10:43:03 AM #19 Text 0 File MMC.cpp, Line 18034 CueData, Len=32 41 00 00 14 00 00 00 00 41 01 00 10 00 00 00 00 41 01 01 10 00 00 02 00 41 aa 01 14 00 46 34 22 10:43:03 AM #20 Text 0 File ThreadedTransfer.cpp, Line 268 Pipe memory size 83836800 10:43:16 AM #21 Text 0 File Cdrdrv.cpp, Line 1405 10:43:16.806 - G: HL-DT-ST DVDRAM GSA-H12N : Queue again later 10:43:42 AM #22 SPTI -1502 File SCSIPassThrough.cpp, Line 181 CdRom1: SCSIStatus(x02) WinError(0) NeroError(-1502) Sense Key: 0x04 (KEY_HARDWARE_ERROR) Nero Report 2 Nero Burning ROM Sense Code: 0x08 Sense Qual: 0x03 CDB Data: 0x2A 00 00 00 4D 00 00 00 20 00 00 00 Sense Area: 0x70 00 04 00 00 00 00 10 53 29 A1 80 08 03 Buffer x0c7d9a40: Len x10000 0xDC 87 EB 41 6E AC 61 5A 07 B2 DB 78 B5 D4 D9 24 0x8D BC 51 38 46 56 0F EE 16 15 5C 5B E3 B0 10 16 0x14 B1 C3 6E 30 2B C4 78 15 AB D5 92 09 B7 81 23 10:43:42 AM #23 CDR -1502 File Writer.cpp, Line 306 DMA-driver error, CRC error G: HL-DT-ST DVDRAM GSA-H12N 10:43:55 AM #24 Phase 38 File dlgbrnst.cpp, Line 1767 Burn process failed at 48x (7,200 KB/s) 10:43:55 AM #25 Text 0 File SCSIPTICommands.cpp, Line 287 SPTIDismountVolume - completed successfully for FSCTL_DISMOUNT_VOLUME 10:44:01 AM #26 Text 0 File Cdrdrv.cpp, Line 11412 DriveLocker: UnLockVolume completed 10:44:01 AM #27 Text 0 File SCSIPTICommands.cpp, Line 450 UnLockMCN - completed sucessfully for IOCTL_STORAGE_MCN_CONTROL Existing drivers: Registry Keys: HKLM\Software\Microsoft\Windows NT\CurrentVersion\WinLogon Nero Report 3

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• WinQual: Why would WER not accept code-signing certificates?

  - by Ian Boyd

  In 2005 i tried to establish a WinQual account with Microsoft, so i could pick up our (if any) crash dump files submitted automatically through Windows Error Reporting (WER). i was not allowed to have my crash dumps, because i don't have a Verisign certificate. Instead i have a cheaper one, generated by a Verisign subsidiary: Thawte. The method in which you join is: you digitally sign a sample exe they provide. This proves that you are the same signer that signed apps that they got crash dumps from in the wild. Cryptographically, the private key is needed to generate a digital signature on an executable. Only the holder of that private key can create a signature with for the matching public key. It doesn't matter who generated that private key. That includes certificates that are generated from: self-signing Wells Fargo DigiCert SecureTrust Trustware QuoVadis GoDaddy Entrust Cybertrust GeoTrust GlobalSign Comodo Thawte Verisign Yet Microsof's WinQual only accepts digital certificates generated by Verisign. Not even Verisign's subsidiaries are good enough (Thawte). Can anyone think of any technical, legal or ethical reason why Microsoft doesn't want to accept code-signing certificates? The WinQual site says: Why Is a Digital Certificate Required for Winqual Membership? A digital certificate helps protect your company from individuals who seek to impersonate members of your staff or who would otherwise commit acts of fraud against your company. Using a digital certificate enables proof of an identity for a user or an organization. Is somehow a Thawte digital certificate not secure? Two years later, i sent a reminder notice to WinQual that i've been waiting to be able to get at my crash dumps. The response from WinQual team was: Hello, Thanks for the reminder. We have notified the appropriate people that this is still a request. In 2008 i asked this question in a Microsoft support forum, and the response was: We are only setup to accept VeriSign Certificates at this point. We have not had an overwhelming demand to support other types of certificates. What can it possibly mean to not be "setup" to accept other kinds of certificates? If the thumbprint of the key that signed the WinQual.exe test app is the same as the thumbprint that signed the executable who's crash dump you got in the wild: it is proven - they are my crash dumps, give them to me. And it's not like there's a special API to check if a Verisign digital signature is valid, as opposed to all other digital signatures. A valid signature is valid no matter who generated the key. Microsoft is free to not trust the signer, but that's not the same as identity. So that is my question, can anyone think of any practical reason why WinQual isn't setup to support digital signatures? One person theorized that the answer is that they're just lazy: Not that I know but I would assume that the team running the winQual system is a live team and not a dev team - as in, personality and skillset geared towards maintenance of existing systems. I could be wrong though. They don't want to do work to change it. But can anyone think of anything that would need to be changed? It's the same logic no matter what generated the key: "does the thumbprint match". What am i missing?

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• iPhone SDK / Objective C Syntax Question

  - by Koppo

  To all, I was looking at the sample project from http://iphoneonrails.com/ and I saw they took the NSObject class and added methods to it for the SOAP calls. Their sample project can be downloaded from here http://iphoneonrails.com/downloads/objective_resource-1.01.zip. My question is related to my lack of knowledge on the following syntax as I haven't seen it yet in a iPhone project. There is a header file called NSObject+ObjectiveResource.h where they declare and change NSObject to have extra methods for this project. Is the "+ObjectiveResource.h" in the name there a special syntax or is that just the naming convention of the developers. Finally inside the class NSObject we have the following #import <Foundation/Foundation.h> @interface NSObject (ObjectiveResource) // Response Formats typedef enum { XmlResponse = 0, JSONResponse, } ORSResponseFormat; // Resource configuration + (NSString *)getRemoteSite; + (void)setRemoteSite:(NSString*)siteURL; + (NSString *)getRemoteUser; + (void)setRemoteUser:(NSString *)user; + (NSString *)getRemotePassword; + (void)setRemotePassword:(NSString *)password; + (SEL)getRemoteParseDataMethod; + (void)setRemoteParseDataMethod:(SEL)parseMethod; + (SEL) getRemoteSerializeMethod; + (void) setRemoteSerializeMethod:(SEL)serializeMethod; + (NSString *)getRemoteProtocolExtension; + (void)setRemoteProtocolExtension:(NSString *)protocolExtension; + (void)setRemoteResponseType:(ORSResponseFormat) format; + (ORSResponseFormat)getRemoteResponseType; // Finders + (NSArray *)findAllRemote; + (NSArray *)findAllRemoteWithResponse:(NSError **)aError; + (id)findRemote:(NSString *)elementId; + (id)findRemote:(NSString *)elementId withResponse:(NSError **)aError; // URL construction accessors + (NSString *)getRemoteElementName; + (NSString *)getRemoteCollectionName; + (NSString *)getRemoteElementPath:(NSString *)elementId; + (NSString *)getRemoteCollectionPath; + (NSString *)getRemoteCollectionPathWithParameters:(NSDictionary *)parameters; + (NSString *)populateRemotePath:(NSString *)path withParameters:(NSDictionary *)parameters; // Instance-specific methods - (id)getRemoteId; - (void)setRemoteId:(id)orsId; - (NSString *)getRemoteClassIdName; - (BOOL)createRemote; - (BOOL)createRemoteWithResponse:(NSError **)aError; - (BOOL)createRemoteWithParameters:(NSDictionary *)parameters; - (BOOL)createRemoteWithParameters:(NSDictionary *)parameters andResponse:(NSError **)aError; - (BOOL)destroyRemote; - (BOOL)destroyRemoteWithResponse:(NSError **)aError; - (BOOL)updateRemote; - (BOOL)updateRemoteWithResponse:(NSError **)aError; - (BOOL)saveRemote; - (BOOL)saveRemoteWithResponse:(NSError **)aError; - (BOOL)createRemoteAtPath:(NSString *)path withResponse:(NSError **)aError; - (BOOL)updateRemoteAtPath:(NSString *)path withResponse:(NSError **)aError; - (BOOL)destroyRemoteAtPath:(NSString *)path withResponse:(NSError **)aError; // Instance helpers for getting at commonly used class-level values - (NSString *)getRemoteCollectionPath; - (NSString *)convertToRemoteExpectedType; //Equality test for remote enabled objects based on class name and remote id - (BOOL)isEqualToRemote:(id)anObject; - (NSUInteger)hashForRemote; @end What is the "ObjectiveResource" in the () mean for NSObject? What is that telling Xcode and the compiler about what is happening..? After that things look normal to me as they have various static and instance methods. I know that by doing this all user classes that inherit from NSObject now have all the extra methods for this project. My question is what is the parenthesis are doing after the NSObject. Is that referencing a header file, or is that letting the compiler know that this class is being over ridden. Thanks again and my apologies ahead of time if this is a dumb question but just trying to learn what I lack.

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• How to do inclusive range queries when only half-open range is supported (ala SortedMap.subMap)

  - by polygenelubricants

  On SortedMap.subMap This is the API for SortedMap<K,V>.subMap: SortedMap<K,V> subMap(K fromKey, K toKey) : Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. This inclusive lower bound, exclusive upper bound combo ("half-open range") is something that is prevalent in Java, and while it does have its benefits, it also has its quirks, as we shall soon see. The following snippet illustrates a simple usage of subMap: static <K,V> SortedMap<K,V> someSortOfSortedMap() { return Collections.synchronizedSortedMap(new TreeMap<K,V>()); } //... SortedMap<Integer,String> map = someSortOfSortedMap(); map.put(1, "One"); map.put(3, "Three"); map.put(5, "Five"); map.put(7, "Seven"); map.put(9, "Nine"); System.out.println(map.subMap(0, 4)); // prints "{1=One, 3=Three}" System.out.println(map.subMap(3, 7)); // prints "{3=Three, 5=Five}" The last line is important: 7=Seven is excluded, due to the exclusive upper bound nature of subMap. Now suppose that we actually need an inclusive upper bound, then we could try to write a utility method like this: static <V> SortedMap<Integer,V> subMapInclusive(SortedMap<Integer,V> map, int from, int to) { return (to == Integer.MAX_VALUE) ? map.tailMap(from) : map.subMap(from, to + 1); } Then, continuing on with the above snippet, we get: System.out.println(subMapInclusive(map, 3, 7)); // prints "{3=Three, 5=Five, 7=Seven}" map.put(Integer.MAX_VALUE, "Infinity"); System.out.println(subMapInclusive(map, 5, Integer.MAX_VALUE)); // {5=Five, 7=Seven, 9=Nine, 2147483647=Infinity} A couple of key observations need to be made: The good news is that we don't care about the type of the values, but... subMapInclusive assumes Integer keys for to + 1 to work. A generic version that also takes e.g. Long keys is not possible (see related questions) Not to mention that for Long, we need to compare against Long.MAX_VALUE instead Overloads for the numeric primitive boxed types Byte, Character, etc, as keys, must all be written individually A special check need to be made for toInclusive == Integer.MAX_VALUE, because +1 would overflow, and subMap would throw IllegalArgumentException: fromKey > toKey This, generally speaking, is an overly ugly and overly specific solution What about String keys? Or some unknown type that may not even be Comparable<?>? So the question is: is it possible to write a general subMapInclusive method that takes a SortedMap<K,V>, and K fromKey, K toKey, and perform an inclusive-range subMap queries? Related questions Are upper bounds of indexed ranges always assumed to be exclusive? Is it possible to write a generic +1 method for numeric box types in Java? On NavigableMap It should be mentioned that there's a NavigableMap.subMap overload that takes two additional boolean variables to signify whether the bounds are inclusive or exclusive. Had this been made available in SortedMap, then none of the above would've even been asked. So working with a NavigableMap<K,V> for inclusive range queries would've been ideal, but while Collections provides utility methods for SortedMap (among other things), we aren't afforded the same luxury with NavigableMap. Related questions Writing a synchronized thread-safety wrapper for NavigableMap On API providing only exclusive upper bound range queries Does this highlight a problem with exclusive upper bound range queries? How were inclusive range queries done in the past when exclusive upper bound is the only available functionality?

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• Is SQL Server DRI (ON DELETE CASCADE) slow?

  - by Aaronaught

  I've been analyzing a recurring "bug report" (perf issue) in one of our systems related to a particularly slow delete operation. Long story short: It seems that the CASCADE DELETE keys were largely responsible, and I'd like to know (a) if this makes sense, and (b) why it's the case. We have a schema of, let's say, widgets, those being at the root of a large graph of related tables and related-to-related tables and so on. To be perfectly clear, deleting from this table is actively discouraged; it is the "nuclear option" and users are under no illusions to the contrary. Nevertheless, it sometimes just has to be done. The schema looks something like this: Widgets | +--- Anvils (1:1) | | | +--- AnvilTestData (1:N) | +--- WidgetHistory (1:N) | +--- WidgetHistoryDetails (1:N) Nothing too scary, really. A Widget can be different types, an Anvil is a special type, so that relationship is 1:1 (or more accurately 1:0..1). Then there's a large amount of data - perhaps thousands of rows of AnvilTestData per Anvil collected over time, dealing with hardness, corrosion, exact weight, hammer compatibility, usability issues, and impact tests with cartoon heads. Then every Widget has a long, boring history of various types of transactions - production, inventory moves, sales, defect investigations, RMAs, repairs, customer complaints, etc. There might be 10-20k details for a single widget, or none at all, depending on its age. So, unsurprisingly, there's a CASCADE DELETE relationship at every level here. If a Widget needs to be deleted, it means something's gone terribly wrong and we need to erase any records of that widget ever existing, including its history, test data, etc. Again, nuclear option. Relations are all indexed, statistics are up to date. Normal queries are fast. The system tends to hum along pretty smoothly for everything except deletes. Getting to the point here, finally, for various reasons we only allow deleting one widget at a time, so a delete statement would look like this: DELETE FROM Widgets WHERE WidgetID = @WidgetID Pretty simple, innocuous looking delete... that takes over 2 minutes to run, for a widget with no data! After slogging through execution plans I was finally able to pick out the AnvilTestData and WidgetHistoryDetails deletes as the sub-operations with the highest cost. So I experimented with turning off the CASCADE (but keeping the actual FK, just setting it to NO ACTION) and rewriting the script as something very much like the following: DECLARE @AnvilID int SELECT @AnvilID = AnvilID FROM Anvils WHERE WidgetID = @WidgetID DELETE FROM AnvilTestData WHERE AnvilID = @AnvilID DELETE FROM WidgetHistory WHERE HistoryID IN ( SELECT HistoryID FROM WidgetHistory WHERE WidgetID = @WidgetID) DELETE FROM Widgets WHERE WidgetID = @WidgetID Both of these "optimizations" resulted in significant speedups, each one shaving nearly a full minute off the execution time, so that the original 2-minute deletion now takes about 5-10 seconds - at least for new widgets, without much history or test data. Just to be absolutely clear, there is still a CASCADE from WidgetHistory to WidgetHistoryDetails, where the fanout is highest, I only removed the one originating from Widgets. Further "flattening" of the cascade relationships resulted in progressively less dramatic but still noticeable speedups, to the point where deleting a new widget was almost instantaneous once all of the cascade deletes to larger tables were removed and replaced with explicit deletes. I'm using DBCC DROPCLEANBUFFERS and DBCC FREEPROCCACHE before each test. I've disabled all triggers that might be causing further slowdowns (although those would show up in the execution plan anyway). And I'm testing against older widgets, too, and noticing a significant speedup there as well; deletes that used to take 5 minutes now take 20-40 seconds. Now I'm an ardent supporter of the "SELECT ain't broken" philosophy, but there just doesn't seem to be any logical explanation for this behaviour other than crushing, mind-boggling inefficiency of the CASCADE DELETE relationships. So, my questions are: Is this a known issue with DRI in SQL Server? (I couldn't seem to find any references to this sort of thing on Google or here in SO; I suspect the answer is no.) If not, is there another explanation for the behaviour I'm seeing? If it is a known issue, why is it an issue, and are there better workarounds I could be using?

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• How do you setup an gsp snippet in grails and with spring-security-core?

  - by egervari

  Hi, I have a block of gsp I'd like to reuse and make into a little gsp snippet: <sec:ifLoggedIn> <g:link controller="user" action="showProfile">My Profile</g:link> | <g:link controller="privateMessage" action="list">Inbox</g:link> | <g:link controller="user" action="showPreferences">Preferences</g:link> | <g:link controller="logout" action="index">Logout</g:link> </sec:ifLoggedIn> <sec:ifNotLoggedIn> <form id="loginForm" action="/myproject/j_spring_security_check" method="POST"> <fieldset> <input type='text' name='j_username' id='username' size="15" /> <input type='password' name='j_password' id='password' size="15" /> <input type="submit" value="Login" class="button" /> <a href="#">Register</a> </fieldset> </form> </sec:ifNotLoggedIn> I have learned that I can use g:render template="_loginStuff" to merge the template in with the rest of the markup. However, doing so with Spring Security results in an error: java.lang.NullPointerException at org.codehaus.groovy.grails.plugins.springsecurity.AnnotationFilterInvocationDefinition.determineUrl(AnnotationFilterInvocationDefinition.java:77) at org.codehaus.groovy.grails.plugins.springsecurity.AbstractFilterInvocationDefinition.getAttributes(AbstractFilterInvocationDefinition.java:76) at org.springframework.security.access.intercept.AbstractSecurityInterceptor.beforeInvocation(AbstractSecurityInterceptor.java:171) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:106) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:78) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter.doFilter(RememberMeAuthenticationFilter.java:112) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:188) at org.codehaus.groovy.grails.plugins.springsecurity.RequestHolderAuthenticationFilter.doFilter(RequestHolderAuthenticationFilter.java:40) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.codehaus.groovy.grails.plugins.springsecurity.MutableLogoutFilter.doFilter(MutableLogoutFilter.java:79) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:149) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.codehaus.groovy.grails.web.servlet.mvc.GrailsWebRequestFilter.doFilterInternal(GrailsWebRequestFilter.java:67) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.codehaus.groovy.grails.web.filters.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:66) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454) at java.lang.Thread.run(Thread.java:619) I have no idea if I am just not using correctly, or if my template needs to be in a special folder... or if Spring-security-core will not allow to be used at all. Help?

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• Python/numpy tricky slicing problem

  - by daver

  Hi stack overflow, I have a problem with some numpy stuff. I need a numpy array to behave in an unusual manner by returning a slice as a view of the data I have sliced, not a copy. So heres an example of what I want to do: Say we have a simple array like this: a = array([1, 0, 0, 0]) I would like to update consecutive entries in the array (moving left to right) with the previous entry from the array, using syntax like this: a[1:] = a[0:3] This would get the following result: a = array([1, 1, 1, 1]) Or something like this: a[1:] = 2*a[:3] # a = [1,2,4,8] To illustrate further I want the following kind of behaviour: for i in range(len(a)): if i == 0 or i+1 == len(a): continue a[i+1] = a[i] Except I want the speed of numpy. The default behavior of numpy is to take a copy of the slice, so what I actually get is this: a = array([1, 1, 0, 0]) I already have this array as a subclass of the ndarray, so I can make further changes to it if need be, I just need the slice on the right hand side to be continually updated as it updates the slice on the left hand side. Am I dreaming or is this magic possible? Update: This is all because I am trying to use Gauss-Seidel iteration to solve a linear algebra problem, more or less. It is a special case involving harmonic functions, I was trying to avoid going into this because its really not necessary and likely to confuse things further, but here goes. The algorithm is this: while not converged: for i in range(len(u[:,0])): for j in range(len(u[0,:])): # skip over boundary entries, i,j == 0 or len(u) u[i,j] = 0.25*(u[i-1,j] + u[i+1,j] + u[i, j-1] + u[i,j+1]) Right? But you can do this two ways, Jacobi involves updating each element with its neighbours without considering updates you have already made until the while loop cycles, to do it in loops you would copy the array then update one array from the copied array. However Gauss-Seidel uses information you have already updated for each of the i-1 and j-1 entries, thus no need for a copy, the loop should essentially 'know' since the array has been re-evaluated after each single element update. That is to say, every time we call up an entry like u[i-1,j] or u[i,j-1] the information calculated in the previous loop will be there. I want to replace this slow and ugly nested loop situation with one nice clean line of code using numpy slicing: u[1:-1,1:-1] = 0.25(u[:-2,1:-1] + u[2:,1:-1] + u[1:-1,:-2] + u[1:-1,2:]) But the result is Jacobi iteration because when you take a slice: u[:,-2,1:-1] you copy the data, thus the slice is not aware of any updates made. Now numpy still loops right? Its not parallel its just a faster way to loop that looks like a parallel operation in python. I want to exploit this behaviour by sort of hacking numpy to return a pointer instead of a copy when I take a slice. Right? Then every time numpy loops, that slice will 'update' or really just replicate whatever happened in the update. To do this I need slices on both sides of the array to be pointers. Anyway if there is some really really clever person out there that awesome, but I've pretty much resigned myself to believing the only answer is to loop in C.

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