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  • PostgreSQL: Rolling back a transaction within a plpgsql function?

    - by jamieb
    Coming from the MS SQL world, I tend to make heavy use of stored procedures. I'm currently writing an application uses a lot of PostgreSQL plpgsql functions. What I'd like to do is rollback all INSERTS/UPDATES contained within a particular function if I get an exception at any point within it. I was originally under the impression that each function is wrapped in it's own transaction and that an exception would automatically rollback everything. However, that doesn't seem to be the case. I'm wondering if I ought to be using savepoints in combination with exception handling instead? But I don't really understand the difference between a transaction and a savepoint to know if this is the best approach. Any advice please? CREATE OR REPLACE FUNCTION do_something( _an_input_var int ) RETURNS bool AS $$ DECLARE _a_variable int; BEGIN INSERT INTO tableA (col1, col2, col3) VALUES (0, 1, 2); INSERT INTO tableB (col1, col2, col3); VALUES (0, 1, 'whoops! not an integer'); -- The exception will cause the function to bomb, but the values -- inserted into "tableA" are not rolled back. RETURN True; END; $$ LANGUAGE plpgsql;

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  • Unable to call RESTful web services methods

    - by Alessandro
    Hello, I'm trying to dive into the RESTful web services world and have started with the following template: [ServiceContract] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)] public class Test { // TODO: Implement the collection resource that will contain the SampleItem instances [WebGet(UriTemplate = ""), OperationContract] public List<SampleItem> GetCollection() { // TODO: Replace the current implementation to return a collection of SampleItem instances return new List<SampleItem>() {new SampleItem() {Id = 1, StringValue = "Hello"}}; } [WebInvoke(UriTemplate = "", Method = "POST"), OperationContract] public SampleItem Create(SampleItem instance) { // TODO: Add the new instance of SampleItem to the collection throw new NotImplementedException(); } [WebGet(UriTemplate = "{id}"), OperationContract] public SampleItem Get(string id) { // TODO: Return the instance of SampleItem with the given id throw new NotImplementedException(); } [WebInvoke(UriTemplate = "{id}", Method = "PUT"), OperationContract] public SampleItem Update(string id, SampleItem instance) { return new SampleItem { Id = 99, StringValue = "Done" }; } [WebInvoke(UriTemplate = "{id}", Method = "DELETE"), OperationContract] public void Delete(string id) { // TODO: Remove the instance of SampleItem with the given id from the collection throw new NotImplementedException(); } } I am able to perform the GET operation but I am unable to perform PUT, POST or DELETE requests. Can anyone explain me how to perform these operations and how to create the correct URLs? Best regards Alessandro

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  • Submit information to url, but also open PDF

    - by Mad Ducky Digital Branding
    I have a client whose desire is to have her Wordpress blog show a MailChimp form on her home page as a gateway to a .pdf. I need the following behavior to occur when the user clicks "Submit": execute the included MailChimp's javascript file; this ensures the form was properly filled, and then performs the sign-up to the newsletter list (don't need help with this part) then show the user an informational PDF for download or viewing EDIT: The logical order was flipped from when I originally posted this. The script should execute, and only if the script gets executed properly should the PDF show to the user Note: My experience level with HTML and PHP is 3/4, and with JS I am 2/4 EDIT: (seems more like 1/4 at this point lol). If my research is correct, PHP (server-side language) would be used to do that which the client wants. Additional validation is not necessary beyond what MailChimp's script provides (it ensures that user has submitted a completed form) is not necessary in this case (the client says it's ok if the e-mail isn't valid at all). EDIT: Reworded this sentence from original post to be more clear The .pdf URL and content is static, and simply needs to be shown, not generated. ----RESEARCH---- I know that the Mailchimp form uses the following line to actually submit the information, but I want to do the action mentioned below, as well as open the aforementioned .pdf: <form action="http://*BLAH*.us2.list-manage.com/subscribe/post?u=*BLAHBLAH*&amp;id=*BLAHBLAHBLAH*" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank"> I am reading on other sites that I can conceivably point "action" to a .php file, but if there is a way to do this with javascript - since its using the .js file that I created for that already anyways, then I would be most happy. Barring that, I'll take what I can get.. ----SOLUTION?---- ...

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  • FluentNHibernate SQLite configuration exception - after switching to .net4

    - by stiank81
    I get an exception thrown when trying to use Fluent to configure my NHibernate connection to SQLite. The code I use to configure is as follows: var cfg = Fluently.Configure(). Database(SQLiteConfiguration.Standard.ShowSql().UsingFile("MyDb.db")). Mappings(m => m.FluentMappings.AddFromAssemblyOf<MappingsPersistenceModel>()); _sessionFactory = cfg.BuildSessionFactory(); A HibernateException is thrown when BuildSessionFactory() is called, saying: Could not create the driver from NHibernate.Driver.SQLite20Driver, NHibernate, Version=2.1.2.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4. It has an InnerException: Exception has been thrown by the target of an invocation. Which again has an InnerException: The IDbCommand and IDbConnection implementation in the assembly System.Data.SQLite could not be found. Ensure that the assembly System.Data.SQLite is located in the application directory or in the Global Assembly Cache. If the assembly is in the GAC, use element in the application configuration file to specify the full name of the assembly. Now - to me it sounds like it doesn't find System.Data.SQLite.dll, but I can't understand this. Everywhere this is referenced I have "Copy Local", and I have verified that it is in every build folder for projects using SQLite. I have also copied it manually to every Debug folder of the solution - without luck. What can be causing this? Any ideas? My suspicion is that it is related to .Net4 somehow. The reason is that it worked just fine when I used .Net3.5, and then I changed to .Net4, and the problem started. You can also check out this other question for a more general approach towards Fluent-.Net4 compatibility.

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  • Pros & Cons of Google App Engine

    - by Rishi
    Pros & Cons of Google App Engine [An Updated List 21st Aug 09] Help me Compile a List of all the Advantages & Disadvantages of Building an Application on the Google App Engine Pros: 1) No Need to buy Servers or Server Space (no maintenance). 2) Makes solving the problem of scaling much easier. Cons: 1) Locked into Google App Engine ?? 2)Developers have read-only access to the filesystem on App Engine. 3)App Engine can only execute code called from an HTTP request (except for scheduled background tasks). 4)Users may upload arbitrary Python modules, but only if they are pure-Python; C and Pyrex modules are not supported. 5)App Engine limits the maximum rows returned from an entity get to 1000 rows per Datastore call. 6)Java applications may only use a subset (The JRE Class White List) of the classes from the JRE standard edition. 7)Java applications cannot create new threads. Known Issues!! http://code.google.com/p/googleappengine/issues/list Hard limits Apps per developer - 10 Time per request - 30 sec Files per app - 3,000 HTTP response size - 10 MB Datastore item size - 1 MB Application code size - 150 MB Pro or Con? App Engine's infrastructure removes many of the system administration and development challenges of building applications to scale to millions of hits. Google handles deploying code to a cluster, monitoring, failover, and launching application instances as necessary. While other services let users install and configure nearly any *NIX compatible software, App Engine requires developers to use Python or Java as the programming language and a limited set of APIs. Current APIs allow storing and retrieving data from a BigTable non-relational database; making HTTP requests; sending e-mail; manipulating images; and caching. Most existing Web applications can't run on App Engine without modification, because they require a relational database.

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  • Is there any way to access files in your source tree in Android?

    - by Chris Thompson
    Hi all, This is a bit unorthodox but I'm trying to figure out if there's a way to access files stored in the src tree of my applications apk in Android. I'm trying to use i-Jetty (Jetty implementation for Android) and rather than use it as a separate application and manually download my war file, I'd rather just bake i-jetty in. However, in order to use (easily) standard html/jsp I need to be able to give it a document root, preferably within my application's apk file. I know Android specifically works to prevent you from accessing (freely) the stuff on the actual system so this may not be possible, but I'm thinking it might be possible to access something within the apk. One option to work around this would be to have all of the files stored in the res directory and then copy them to the sdcard on startup but this wouldn't allow me to automatically remove the files on uninstall. To give you an idea of what I've tried, currently, the html files are stored in org.webtext.android Context rootContext = new Context(server_, "/", Context.SESSIONS); rootContext.setResourceBase("org/webtext/webapp"); Returns a 404 error. final URL url = this.getClassLoader().getResource("org/webtext/webapp"); Context html = new WebAppContext(url.toExternalForm(), "/"); Blows up with a NullPointerException because no URL is returned from the getResource call. Any thoughts would be greatly appreciated! Thanks, Chris

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  • Is there a good tutorial for figuring out what a website is doing so your program can do the same th

    - by brian d foy
    Is there a good guide or tutorial for people who need to programmatically interact with dynamic websites? There's been a rash of Perl questions about that lately, and I haven't found a good resource to point people toward. I'm asking not because I need one but because I don't want to waste my time writing it if it already exists. Although I'm most interested in Perl, the extra tools and techniques are mostly the same. Typically, I see see these problems in people's questions: Handling, setting, and saving cookies Finding and interacting with forms Handling JavaScript inside your user-agent especially things like onLoad, onSumbit, and Ajax Using HTTP sniffer tools Using Web developer plugins in interactive browsers Interacting with DOM, screen scraping, etc. If there's no good tutorial, I'll add it to my list of things to do (unless someone else wants to do it :). Along the way, if you don't have a suggestion for an existing tutorial, please suggest the things that you think should be in a new one, including links, your favorite tools, and your own user-agent development experiences. I don't care about the particular language you use.

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  • Stuck on preserving config file in WIX major upgrade!

    - by Joshua
    ARGH! Wix is driving me crazy. So, of course I have seen the many posts both here on stackoverflow and elsewhere about WiX and major upgrades. I inherited this software project using WiX and am releasing a new version. I need this new version to leave ONLY the one configuration file if it's present, and replace everything else. This installer works EXCEPT no matter what I have done so far, the new XML file replaces the old on every install. Even attempting to use NeverOverwrite="yes" and even trying and messing back and forth with OnlyDetect="no"! I am simply stuck and humbly request a little guidance. The file that needs to be preserved is called SETTINGS.XML and is in the All Users-ApplicationData directory. Here is (most of) my .wxs file! <Package Id='$(var.PackageCode)' Description="Pathways Directory Software" InstallerVersion="301" Compressed="yes" /> <WixVariable Id="WixUILicenseRtf" Value="License.rtf" /> <Media Id="1" Cabinet="Pathways.cab" EmbedCab="yes" /> <Upgrade Id="$(var.UpgradeCode)"> <UpgradeVersion OnlyDetect="no" Maximum="$(var.ProductVersion)" IncludeMaximum="no" Language="1033" Property="OLDAPPFOUND" /> <UpgradeVersion Minimum="$(var.ProductVersion)" IncludeMinimum="yes" OnlyDetect="no" Language="1033" Property="NEWAPPFOUND" /> </Upgrade> <!-- program files directory --> <Directory Id="ProgramFilesFolder"> <Directory Id="INSTALLDIR" Name="Pathways"/> </Directory> <!-- application data directory --> <Directory Id="CommonAppDataFolder" Name="CommonAppData"> <Directory Id="CommonAppDataPathways" Name="Pathways" /> </Directory> <!-- start menu program directory --> <Directory Id="ProgramMenuFolder"> <Directory Id="ProgramsMenuPathwaysFolder" Name="Pathways" /> </Directory> <!-- desktop directory --> <Directory Id="DesktopFolder" /> </Directory> <Icon Id="PathwaysIcon" SourceFile="\\Fileserver\Release\Pathways\Latest\Release\Pathways.exe" /> <!-- components in the reference to the install directory --> <DirectoryRef Id="INSTALLDIR"> <Component Id="Application" Guid="EEE4EB55-A515-4872-A4A5-06D6AB4A06A6"> <File Id="pathwaysExe" Name="Pathways.exe" DiskId="1" Source="\\Fileserver\Release\Pathways\Latest\Release\Pathways.exe" Vital="yes" KeyPath="yes" Assembly=".net" AssemblyApplication="pathwaysExe" AssemblyManifest="pathwaysExe"> <!--<netfx:NativeImage Id="ngen_Pathways.exe" Platform="32bit" Priority="2"/> --> </File> <File Id="pathwaysChm" Name="Pathways.chm" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\Pathways.chm" /> <File Id="publicKeyXml" ShortName="RSAPUBLI.XML" Name="RSAPublicKey.xml" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\RSAPublicKey.xml" Vital="yes" /> <File Id="staticListsXml" ShortName="STATICLI.XML" Name="StaticLists.xml" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\StaticLists.xml" Vital="yes" /> <File Id="axInteropMapPointDll" ShortName="AXMPOINT.DLL" Name="AxInterop.MapPoint.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\AxInterop.MapPoint.dll" Vital="yes" /> <File Id="interopMapPointDll" ShortName="INMPOINT.DLL" Name="Interop.MapPoint.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\Interop.MapPoint.dll" Vital="yes" /> <File Id="mapPointDll" ShortName="MAPPOINT.DLL" Name="MapPoint.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\Interop.MapPoint.dll" Vital="yes" /> <File Id="devExpressData63Dll" ShortName="DAAT63.DLL" Name="DevExpress.Data.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.Data.v6.3.dll" Vital="yes" /> <File Id="devExpressUtils63Dll" ShortName="UTILS63.DLL" Name="DevExpress.Utils.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.Utils.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraBars63Dll" ShortName="BARS63.DLL" Name="DevExpress.XtraBars.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraBars.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraNavBar63Dll" ShortName="NAVBAR63.DLL" Name="DevExpress.XtraNavBar.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraNavBar.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraCharts63Dll" ShortName="CHARTS63.DLL" Name="DevExpress.XtraCharts.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraCharts.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraEditors63Dll" ShortName="EDITOR63.DLL" Name="DevExpress.XtraEditors.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraEditors.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraPrinting63Dll" ShortName="PRINT63.DLL" Name="DevExpress.XtraPrinting.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraPrinting.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraReports63Dll" ShortName="REPORT63.DLL" Name="DevExpress.XtraReports.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraReports.v6.3.dll" Vital="yes" /> <File Id="devExpressXtraRichTextEdit63Dll" ShortName="RICHTE63.DLL" Name="DevExpress.XtraRichTextEdit.v6.3.dll" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\DevExpress.XtraRichTextEdit.v6.3.dll" Vital="yes" /> <RegistryValue Id="PathwaysInstallDir" Root="HKLM" Key="Software\Tribal Data Resources\Pathways" Name="InstallDir" Action="write" Type="string" Value="[INSTALLDIR]" /> </Component> </DirectoryRef> <!-- application data components --> <DirectoryRef Id="CommonAppDataPathways"> <Component Id="CommonAppDataPathwaysFolderComponent" Guid="087C6F14-E87E-4B57-A7FA-C03FC8488E0D"> <CreateFolder> <Permission User="Everyone" GenericAll="yes" /> </CreateFolder> <RemoveFolder Id="CommonAppDataPathways" On="uninstall" /> <RegistryValue Root="HKCU" Key="Software\TDR\Pathways" Name="installed" Type="integer" Value="1" KeyPath="yes" /> <File Id="settingsXml" ShortName="SETTINGS.XML" Name="Settings.xml" DiskId="1" Source="\\fileserver\Release\Pathways\Dependencies\Settings\settings.xml" Vital="yes" /> </Component> <Component Id="Database" Guid="1D8756EF-FD6C-49BC-8400-299492E8C65D"> <File Id="pathwaysMdf" Name="Pathways.mdf" DiskId="1" Source="\\fileserver\Shared\Databases\Pathways\SystemDBs\Pathways.mdf" /> <RemoveFile Id="pathwaysLdf" ShortName="Pathways.ldf" Name="Pathways_log.LDF" On="uninstall" /> </Component> </DirectoryRef> <!-- shortcut components --> <DirectoryRef Id="DesktopFolder"> <Component Id="DesktopShortcutComponent" Guid="1BF412BA-9C6B-460D-80ED-8388AC66703F"> <Shortcut Id="DesktopShortcut" Target="[INSTALLDIR]Pathways.exe" Name="Pathways" Description="Pathways Tribal Directory" Icon="PathwaysIcon" Show="normal" WorkingDirectory="INSTALLDIR" /> <RegistryValue Root="HKCU" Key="Software\TDR\Pathways" Name="installed" Type="integer" Value="1" KeyPath="yes"/> </Component> </DirectoryRef> <DirectoryRef Id ="ProgramsMenuPathwaysFolder"> <Component Id="ProgramsMenuShortcutComponent" Guid="83A18245-4C22-4CDC-94E0-B480F80A407D"> <Shortcut Id="ProgramsMenuShortcut" Target="[INSTALLDIR]Pathways.exe" Name="Pathways" Icon="PathwaysIcon" Show="normal" WorkingDirectory="INSTALLDIR" /> <RemoveFolder Id="ProgramsMenuPathwaysFolder" On="uninstall"/> <RegistryValue Root="HKCU" Key="Software\TDR\Pathways" Name="installed" Type="integer" Value="1" KeyPath="yes"/> </Component> </DirectoryRef> <Feature Id="App" Title="Pathways Application" Level="1" Description="Pathways software" Display="expand" ConfigurableDirectory="INSTALLDIR" Absent="disallow" AllowAdvertise="no" InstallDefault="local"> <ComponentRef Id="Application" /> <ComponentRef Id="CommonAppDataPathwaysFolderComponent" /> <ComponentRef Id="ProgramsMenuShortcutComponent" /> <Feature Id="Shortcuts" Title="Desktop Shortcut" Level="1" Absent="allow" AllowAdvertise="no" InstallDefault="local"> <ComponentRef Id="DesktopShortcutComponent" /> </Feature> </Feature> <Feature Id="Data" Title="Database" Level="1" Absent="allow" AllowAdvertise="no" InstallDefault="local"> <ComponentRef Id="Database" /> </Feature> <!-- <UIRef Id="WixUI_Minimal" /> --> <UIRef Id ="WixUI_FeatureTree"/> <UIRef Id="WixUI_ErrorProgressText"/> <UI> <Error Id="2000">There is a later version of this program installed.</Error> </UI> <CustomAction Id="NewerVersionDetected" Error="2000" /> <InstallExecuteSequence> <RemoveExistingProducts After="InstallFinalize"/> </InstallExecuteSequence> </Product>

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  • How can I build something like Amazon S3 in Perl?

    - by Joel G
    I am looking to code a file storage application in perl similar to amazon s3. I already have a amazon s3 clone that I found online called parkplace but its in ruby and is old also isn't built for high loads. I am not really sure what modules and programs I should use so id like some help picking them out. My requirements are listed below (yes I know there are lots but I could start simple then add more once I get it going): Easy API implementation for client side apps. (maybe REST (?) Centralized database server for the USERDB (maybe PostgreSQL (?). Logging of all connections, bandwidth used, well pretty much everything to a centralized server (maybe PostgreSQL again (?). Easy server side configuration (config file(s) stored on the servers). Web based control panel for admin(s) and user(s) to show logs. (could work just running queries from the databases) Fast High Uptime Low memory usage Some sort of load distribution/load balancer (maybe a dns based or pound or perlbal or something else (?). Maybe a cache of some sort (memcached or parlbal or something else (?). Thanks in advance

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  • html to text with domdocument class

    - by turbod
    How to get a html page source code without htl tags? For example: <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <meta http-equiv="content-language" content="hu"/> <title>this is the page title</title> <meta name="description" content="this is the description" /> <meta name="keywords" content="k1, k2, k3, k4" /> start the body content <!-- <div>this is comment</div> --> <a href="open.php" title="this is title attribute">open</a> End now one noframes tag. <noframes><span>text</span></noframes> <select name="select" id="select"><option>ttttt</option></select> <div class="robots-nocontent"><span>something</span></div> <img src="url.png" alt="this is alt attribute" /> I need this result: this is the page title this is the description k1, k2, k3, k4 start the body content this is title attribute open End now one noframes tag. text ttttt something this is alt attribute I need too the title and the alt attributes. Idea?

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  • Monotouch or Titanium for rapid application development on IPhone?

    - by Ronnie
    As a .Net developer I always dreamed for the possibility to develop with my existing skills (c#) applications for the Iphone. Both programs require a Mac and the Iphone Sdk installed. Appcelerator Titanium was the first app I tried and it is based on exposing some Iphone native api to javascript so that they can be called using that language. Monotouch starts at $399 for beeing able to deploy on the Iphone and not on the Iphone simulator while Titanium is free. Monotouch (Monodevelop) has an Ide that is currently missing in Titanium (but you can use any editor like Textmate, Aptana...) I think both program generate at the end a native precompiled app (also if I am not sure about the size of the final app on the Iphone as I think the .Net framework calls are prelilnked at compilation time in Monotouch). I am also not sure about the full coverage of all the Iphone api and features. Titanium has also the advantage to enable Android app development but as a c# developer I still find Monotouch experience more like the Visual Studio one. Witch one would you choose and what are your experiences on Monotouch and Titanium?

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  • Jquery getJSON() doesn't work when trying to get data from java server on localhost

    - by bellesebastien
    The whole day yesterday I've been trying to solve this but it's proven to be very challenging for me. I'm trying to use this JS to get information from a java application I wrote. $(document).ready(function() { $.getJSON('http://localhost/custest?callback=?', function(json) { alert('OK'); $('.result').html(json.description); }); }); The Java application uses httpServer and is very basic. When I access the page 'http://localhost/custest?callback=?' with Firefox, the browser shows me the server is sending me json data and asks with what to open it with, but when I try it from a webpage using the JS above it doesn't work. The getJSON call is not successful, the alert("ok") doesn't popup at all. If it replace "http://localhost/custest?callback=?" in the JS with "http://twitter.com/users/usejquery.json?callback=?" everything works fine. An interesting thing is that if I send malformed JSON from my java server Firebug gives an error and tells me what is missing from the JSON so that mean the browser is receiving the JSON data, but when I send it correct a JSON string nothing happens, no errors, not even the alert() opens. I'm adding the headers in case you think these could be relevant. http://localhost/custest?callback=jsonp1274691110349 GET /custest?callback=jsonp1274691110349 HTTP/1.1 Host: localhost User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 Accept: */* Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 115 Connection: keep-alive HTTP/1.1 200 OK Transfer-Encoding: chunked Content-Type: application/json Thanks for your help

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  • How do I pass a callback function to sqlite3_exec on iOS 5.1?

    - by John Doh
    I am new to both xcode/iOS/Objective-C and sqlite. I am trying to teach myself the basics - and I would like to use the sqlite3 wrapper "sqlite3_exec" for a select query. For some reason, I can't find a simple example anywhere of someone doing this. Basically, the method has a parameter (the third one) for a callback function: int sqlite3_exec( sqlite3*, /* An open database */ const char *sql, /* SQL to be evaluated */ int (*callback)(void*,int,char**,char**), /* Callback function */ void *, /* 1st argument to callback */ char **errmsg /* Error msg written here */ ); That's fine. I'm no stranger to callbacks. However, I just can't seem to get the syntax down right. I took over one of the view controllers in my iPad (iOS 5.1) xcode (4.3) project, and made the changes shown below: #import "SecondViewController.h" #import "sqlite3.h" #import "AppState.h" @interface SecondViewController () @end @implementation SecondViewController - (int)myCallback:(void *)a_parm argc:(int)argc argv:(char **)argv column:(char **)column { return 0; } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. //grab questionnaire names char *sql = "select * from QST2Main order by [Name]"; char *err = nil; sqlite3 *db = [[AppState sharedManager] getgCn]; sqlite3_exec(db, sql, myCallback, nil, &err); } Essentially, I want to run a query when this view first loads, to store some data for later use. But, XCode doesn't like the "myCallback" usage at the bottom there. It says: Undeclared Use of Identifier 'myCallback.' That method is declared in the header file, and I've even tried making it static. Nothing seems to make this error go away. I know I must be doing something fundamentally wrong here, but for the life of me I can't figure out what - I can't even find other code samples in this area that could help me figure out what I'm missing. Many thanks!

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  • Porting Oracle Procedure to PostgreSQL

    - by Grasper
    I am porting an Oracle function into Postgres PGPLSQL.. I have been using this guide: http://www.postgresql.org/docs/8.1/static/plpgsql.html CREATE OR REPLACE PROCEDURE DATA_UPDATE (mission NUMBER, task NUMBER) AS BEGIN IF mission IS NOT NULL THEN UPDATE MISSION_OBJECTIVE MO SET (MO.MO_TKR_TOTAL_OFF_SCHEDULED, MO.MO_TKR_TOTAL_RECEIVERS) = (SELECT NVL(SUM(RR.TRQ_FUEL_OFFLOAD),0), NVL(SUM(RR.TRQ_NUMBER_RECEIVERS),0) FROM REFUELING_REQUEST RR, MISSION_REQUEST_PAIRING MRP WHERE MO.MSN_INT_ID = MRP.MSN_INT_ID AND MO.MO_INT_ID = MRP.MO_INT_ID AND MRP.REQ_INT_ID = RR.REQ_INT_ID) WHERE MO.MSN_INT_ID = mission AND MO.MO_INT_ID = task ; END IF ; COMMIT ; END ; I've got it this far: CREATE OR REPLACE FUNCTION DATA_UPDATE (NUMERIC, NUMERIC) RETURNS integer as ' DECLARE mission ALIAS for $1; task ALIAS for $2; BEGIN IF mission IS NOT NULL THEN UPDATE MISSION_OBJECTIVE MO SET (MO.MO_TKR_TOTAL_OFF_SCHEDULED, MO.MO_TKR_TOTAL_RECEIVERS) = (SELECT COALESCE(SUM(RR.TRQ_FUEL_OFFLOAD),0), COALESCE(SUM(RR.TRQ_NUMBER_RECEIVERS),0) FROM REFUELING_REQUEST RR, MISSION_REQUEST_PAIRING MRP WHERE MO.MSN_INT_ID = MRP.MSN_INT_ID AND MO.MO_INT_ID = MRP.MO_INT_ID AND MRP.REQ_INT_ID = RR.REQ_INT_ID) WHERE MO.MSN_INT_ID = mission AND MO.MO_INT_ID = task ; END IF; COMMIT; END; ' LANGUAGE plpgsql; This is the error I get: ERROR: syntax error at or near "SELECT" LINE 1: ...OTAL_OFF_SCHEDULED, MO.MO_TKR_TOTAL_RECEIVERS) = (SELECT COA... I do not know why this isn't working... any ideas?

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  • Hosting Multiple hosts under IIS for WCF

    - by Josh
    Hello everyone, I need to use multiple hosts under IIS for WCF. We're using wshttpbinding and we've found NO success so far even after checking out a couple of similar questions on stackoveflow. Here is my web.config <?xml version="1.0"?> <!-- Note: As an alternative to hand editing this file you can use the web admin tool to configure settings for your application. Use the Website->Asp.Net Configuration option in Visual Studio. A full list of settings and comments can be found in machine.config.comments usually located in \Windows\Microsoft.Net\Framework\v2.x\Config --> <configuration> <configSections> <sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"> <sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"> <section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/> <sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"> <section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="Everywhere"/> <section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/> <section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/> <section name="roleService" type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/> </sectionGroup> </sectionGroup> </sectionGroup> </configSections> <appSettings/> <connectionStrings> <add name="ConString" connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=WebSMS20July;Integrated Security=True"/> </connectionStrings> <system.web> <customErrors mode="Off"/> <!--<httpRuntime maxRequestLength="999999999" useFullyQualifiedRedirectUrl="true" executionTimeout="459999999" appRequestQueueLimit="99999999" delayNotificationTimeout="999999999" maxWaitChangeNotification="999999999" shutdownTimeout="9999999999"/>--> <!-- Set compilation debug="true" to insert debugging symbols into the compiled page. Because this affects performance, set this value to true only during development. --> <compilation debug="true"> <assemblies> <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </assemblies> </compilation> <!-- The <authentication> section enables configuration of the security authentication mode used by ASP.NET to identify an incoming user. --> <authentication mode="Windows"/> <!-- The <customErrors> section enables configuration of what to do if/when an unhandled error occurs during the execution of a request. Specifically, it enables developers to configure html error pages to be displayed in place of a error stack trace. <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm"> <error statusCode="403" redirect="NoAccess.htm" /> <error statusCode="404" redirect="FileNotFound.htm" /> </customErrors>--> <pages> <controls> <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </controls> </pages> <httpHandlers> <remove verb="*" path="*.asmx"/> <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validate="false"/> </httpHandlers> <httpModules> <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </httpModules> </system.web> <system.codedom> <compilers> <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <providerOption name="CompilerVersion" value="v3.5"/> <providerOption name="WarnAsError" value="false"/> </compiler> </compilers> </system.codedom> <!-- The system.webServer section is required for running ASP.NET AJAX under Internet Information Services 7.0. It is not necessary for previous version of IIS. --> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <modules> <add name="ScriptModule" preCondition="integratedMode" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </modules> <handlers> <remove name="WebServiceHandlerFactory-Integrated"/> <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </handlers> </system.webServer> <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="true"> <baseAddressPrefixFilters> <add prefix="http://localhost:12350"/> </baseAddressPrefixFilters> </serviceHostingEnvironment> <bindings> <wsHttpBinding> <binding name="wsHttpBinding" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"> <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" /> <security mode="None"> <transport clientCredentialType="None" /> <message clientCredentialType="None" negotiateServiceCredential="false" establishSecurityContext="false" /> </security> </binding> <binding name="NewBinding0" /> </wsHttpBinding> </bindings> <services> <service behaviorConfiguration="WcfService1.Service1Behavior" name="WcfService1.Service1"> <endpoint address="" binding="wsHttpBinding" bindingConfiguration="wsHttpBinding" bindingName="wsHttpBinding" contract="WcfService1.IService1"> <identity> <dns value="localhost" /> </identity> </endpoint> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> <endpoint binding="wsHttpBinding" bindingConfiguration="wsHttpBinding" bindingName="wsHttpBinding2" contract="WcfService1.IService1" listenUri="http://localhost:8090" /> <host> <baseAddresses> <add baseAddress="http://mydomain/mywcfservice/Service1.svc" /> <add baseAddress="http://localhost/mywcfservice/Service1.svc" /> </baseAddresses> </host> </service> </services> <behaviors> <serviceBehaviors> <behavior name="WcfService1.Service1Behavior"> <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment --> <serviceMetadata httpGetEnabled="true"/> <!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information --> <serviceDebug includeExceptionDetailInFaults="false"/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> </configuration> Here's my service factory class using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.ServiceModel; using System.ServiceModel.Activation; namespace WcfService1 { public class CustomHostFactory : ServiceHostFactory { protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses) { //CustomHost customServiceHost = // new CustomHost(serviceType, baseAddresses[1]); //return customServiceHost; ServiceHost host; host = new ServiceHost(serviceType, baseAddresses[0]); return host; } class CustomHost : ServiceHost { public CustomHost(Type serviceType, params Uri[] baseAddresses) : base(serviceType, baseAddresses) { } protected override void ApplyConfiguration() { base.ApplyConfiguration(); } } } } Contents of my Service1.svc file <%@ ServiceHost Language="C#" Debug="true" Service="WcfService1.Service1" CodeBehind="Service1.svc.cs" Factory="WcfService1.CustomHostFactory" %> What could possibly be wrong? Would appreciate any help. Thanks.

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  • Basic jUnit Questions

    - by Epitaph
    I was testing a String multiplier class with a multiply() method that takes 2 numbers as inputs (as String) and returns the result number (as String) `public String multiply(String num1, String num2); I have done the implementation and created a test class with the following test cases involving the input String parameter as 1) valid numbers 2) characters 3) special symbol 4) empty string 5) Null value 6) 0 7) Negative number 8) float 9) Boundary values 10) Numbers that are valid but their product is out of range 11) numbers will + sign (+23) 1) I'd like to know if "each and every" assertEquals() should be in it's own test method? Or, can I group similar test cases like testInvalidArguments() to contains all asserts involving invalid characters since ALL of them throw the same NumberFormatException ? 2) If testing an input value like character ("a"), do I need to include test cases for ALL scenarios? "a" as the first argument "a" as the second argument "a" and "b" as the 2 arguments 3) As per my understanding, the benefit of these unit tests is to find out the cases where the input from a user might fail and result in an exception. And, then we can give the user with a meaningful message (asking them to provide valid input) instead of an exception. Is that the correct? And, is it the only benefit? 4) Are the 11 test cases mentioned above sufficient? Did I miss something? Did I overdo? When is enough? 5) Following from the above point, have I successfully tested the multiply() method?

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  • .NET Membership with Repository Pattern

    - by Zac
    My team is in the process of designing a domain model which will hide various different data sources behind a unified repository abstraction. One of the main drivers for this approach is the very high probability that these data sources will undergo significant change in the near future and we don't want to be re-writing business logic when this happens. One data source will be our membership database which was originally implemented using the default ASP.Net Membership Provider. The membership provider is tied to the System.Web.Security namespace but we have a design guideline requiring that our domain model layer is not dependent upon System.Web (or any other implementation/environment dependency) as it will be consumed in different environments - nor do we want our websites directly communicating with databases. I am considering what would be a good approach to reconciling the MembershipProvider approach with our abstracted n-tier architecture. My initial feeling is that we could create a "DomainMembershipProvider" which interacts with the domain model and then implement objects in the model which deal with the repository and handle validation/business logic. The repository would then implement data access using our (as-yet undecided) ORM/data access tool. Are there are any glaring holes in this approach - I haven't worked closely with the MembershipProvider class so may well be missing something. Alternatively, is there an approach that you think will better serve the requirements I described above? Thanks in advance for your thoughts and advice. Regards, Zac

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  • Detecting Xml namespace fast

    - by Anna Tjsoken
    Hello there, This may be a very trivial problem I'm trying to solve, but I'm sure there's a better way of doing it. So please go easy on me. I have a bunch of XSD files that are internal to our application, we have about 20-30 Xml files that implement datasets based off those XSDs. Some Xml files are small (<100Kb), others are about 3-4Mb with a few being over 10Mb. I need to find a way of working out what namespace these Xml files are in order to provide (something like) intellisense based off the XSD. The implementation of this is not an issue - another developer has written the code for this. But I'm not sure the best (and fastest!) way of detecting the namespace is without the use of XmlDocument (which does a full parse). I'm using C# 3.5 and the documents come through as a Stream (some are remote files). All the files are *.xml (I can detect if it was extension based) but unfortunately the Xml namespace is the only way. Right now I've tried XmlDocument but I've found it to be innefficient and slow as the larger documents are awaiting to be parsed (even the 100Kb docs). public string GetNamespaceForDocument(Stream document); Something like the above is my method signature - overloads include string for "content". Would a RegEx (compiled) pattern be good? How does Visual Studio manage this so efficiently? Another college has told me to find a fast Xml parser in C/C++, parse the content and have a stub that gives back the namespace as its slower in .NET, is this a good idea?

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  • Asymptotic complexity of a compiler

    - by Meinersbur
    What is the maximal acceptable asymptotic runtime of a general-purpose compiler? For clarification: The complexity of compilation process itself, not of the compiled program. Depending on the program size, for instance, the number of source code characters, statements, variables, procedures, basic blocks, intermediate language instructions, assembler instructions, or whatever. This is highly depending on your point of view, so this is a community wiki. See this from the view of someone who writes a compiler. Will the optimisation level -O4 ever be used for larger programs when one of its optimisations takes O(n^6)? Related questions: When is superoptimisation (exponential complexity or even incomputable) acceptable? What is acceptable for JITs? Does it have to be linear? What is the complexity of established compilers? GCC? VC? Intel? Java? C#? Turbo Pascal? LCC? LLVM? (Reference?) If you do not know what asymptotic complexity is: How long are you willing to wait until the compiler compiled your project? (scripting languages excluded)

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  • How do you create a non-Thread-based Guice custom Scope?

    - by Russ
    It seems that all Guice's out-of-the-box Scope implementations are inherently Thread-based (or ignore Threads entirely): Scopes.SINGLETON and Scopes.NO_SCOPE ignore Threads and are the edge cases: global scope and no scope. ServletScopes.REQUEST and ServletScopes.SESSION ultimately depend on retrieving scoped objects from a ThreadLocal<Context>. The retrieved Context holds a reference to the HttpServletRequest that holds a reference to the scoped objects stored as named attributes (where name is derived from com.google.inject.Key). Class SimpleScope from the custom scope Guice wiki also provides a per-Thread implementation using a ThreadLocal<Map<Key<?>, Object>> member variable. With that preamble, my question is this: how does one go about creating a non-Thread-based Scope? It seems that something that I can use to look up a Map<Key<?>, Object> is missing, as the only things passed in to Scope.scope() are a Key<T> and a Provider<T>. Thanks in advance for your time.

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  • Virtual Lan on the Cloud -- Help Confirm my understanding?

    - by marfarma
    [Note: Tried to post this over at ServerFault, but I don't have enough 'points' for more than one link. Powers that be, move this question over there.] Please give this a quick read and let me know if I'm missing something before I start trying to make this work. I'm not a systems admin professional, and I'd hate to end up banging my head into the wall if I can avoid it. Goals: Create a 'road-warrior' capable star shaped virtual LAN for consultants who spend the majority of their time on client sites, and who's firm has no physical network or servers. Enable CIFS access to a cloud-server based installation of Alfresco Allow Eventual implementation of some form of single-sign-on ( OpenLDAP server ) access to Alfresco and other server applications implemented in the future Given: All Servers will live in the public internet cloud (Rackspace Cloud Servers) OpenVPN Server will be a Linux disto, probably Ubuntu 9.x, installed on same server as Alfresco (at least to start) Staff will access server applications and resources from client sites, hotels, trains, planes, coffee shops or their homes over various ISP, using their company laptops or personal home desktops. Based on my Research thus far, to accomplish this, I'll need: OpenVPN with Bridging Enabled to create a star shaped "virtual" LAN http://openvpn.net/index.php/open-source/documentation/miscellaneous/76-ethernet-bridging.html A Road Warrior Network Configuration, as described in this Shorewall article (lower down the page) http://www.shorewall.net/OPENVPN.html Configure bridge addressesing (probably DHCP) http://openvpn.net/index.php/open-source/faq.html#bridge-addressing Configure CIFS / Samba to accept VPN IP address http://serverfault.com/questions/137933/howto-access-samba-share-over-vpn-tunnel Set up Client software, with keys configured for access (potentially through a OpenVPN-Sa client portal) http://www.openvpn.net/index.php/access-server/download-openvpn-as/221-installation-overview.html

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  • Simulating pass by reference for an array in Java

    - by Leif Andersen
    I was wondering, in java, is it possible to in anyway, simulate pass by reference for an array? Yes, I know the language doesn't support it, but is there anyway I can do it. Say, for example, I want to create a method that reverses the order of all the elements in an array. (I know that this code snippet isn't the best example, as there is a better algorithms to do this, but this is a good example of the type of thing I want to do for more complex problems). Currently, I need to make a class like this: public static void reverse(Object[] arr) { Object[] tmpArr = new Object[arr.length]; count = arr.length - 1; for(Object i : arr) tmpArr[count--] = i; // I would like to do arr = tmpArr, but that will only make the shallow // reference tmpArr, I would like to actually change the pointer they passed in // Not just the values in the array, so I have to do this: count = arr.length - 1; for(Object i : tmpArr) arr[count--] = i; return; } Yes, I know that I could just swap the values until I get to the middle, and it would be much more efficient, but for other, more complex purposes, is there anyway that I can manipulate the actual pointer? Again, thank you.

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  • How to mmap the stack for the clone() system call on linux?

    - by Joseph Garvin
    The clone() system call on Linux takes a parameter pointing to the stack for the new created thread to use. The obvious way to do this is to simply malloc some space and pass that, but then you have to be sure you've malloc'd as much stack space as that thread will ever use (hard to predict). I remembered that when using pthreads I didn't have to do this, so I was curious what it did instead. I came across this site which explains, "The best solution, used by the Linux pthreads implementation, is to use mmap to allocate memory, with flags specifying a region of memory which is allocated as it is used. This way, memory is allocated for the stack as it is needed, and a segmentation violation will occur if the system is unable to allocate additional memory." The only context I've ever heard mmap used in is for mapping files into memory, and indeed reading the mmap man page it takes a file descriptor. How can this be used for allocating a stack of dynamic length to give to clone()? Is that site just crazy? ;) In either case, doesn't the kernel need to know how to find a free bunch of memory for a new stack anyway, since that's something it has to do all the time as the user launches new processes? Why does a stack pointer even need to be specified in the first place if the kernel can already figure this out?

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  • Memory mapped files and "soft" page faults. Unavoidable?

    - by Robert Oschler
    I have two applications (processes) running under Windows XP that share data via a memory mapped file. Despite all my efforts to eliminate per iteration memory allocations, I still get about 10 soft page faults per data transfer. I've tried every flag there is in CreateFileMapping() and CreateFileView() and it still happens. I'm beginning to wonder if it's just the way memory mapped files work. If anyone there knows the O/S implementation details behind memory mapped files I would appreciate comments on the following theory: If two processes share a memory mapped file and one process writes to it while another reads it, then the O/S marks the pages written to as invalid. When the other process goes to read the memory areas that now belong to invalidated pages, this causes a soft page fault (by design) and the O/S knows to reload the invalidated page. Also, the number of soft page faults is therefore directly proportional to the size of the data write. My experiments seem to bear out the above theory. When I share data I write one contiguous block of data. In other words, the entire shared memory area is overwritten each time. If I make the block bigger the number of soft page faults goes up correspondingly. So, if my theory is true, there is nothing I can do to eliminate the soft page faults short of not using memory mapped files because that is how they work (using soft page faults to maintain page consistency). What is ironic is that I chose to use a memory mapped file instead of a TCP socket connection because I thought it would be more efficient. Note, if the soft page faults are harmless please note that. I've heard that at some point if the number is excessive, the system's performance can be marred. If soft page faults intrinsically are not significantly harmful then if anyone has any guidelines as to what number per second is "excessive" I'd like to hear that. Thanks.

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  • Graph limitations - Should I use Decorator?

    - by Nick Wiggill
    I have a functional AdjacencyListGraph class that adheres to a defined interface GraphStructure. In order to layer limitations on this (eg. acyclic, non-null, unique vertex data etc.), I can see two possible routes, each making use of the GraphStructure interface: Create a single class ("ControlledGraph") that has a set of bitflags specifying various possible limitations. Handle all limitations in this class. Update the class if new limitation requirements become apparent. Use the decorator pattern (DI, essentially) to create a separate class implementation for each individual limitation that a client class may wish to use. The benefit here is that we are adhering to the Single Responsibility Principle. I would lean toward the latter, but by Jove!, I hate the decorator Pattern. It is the epitome of clutter, IMO. Truthfully it all depends on how many decorators might be applied in the worst case -- in mine so far, the count is seven (the number of discrete limitations I've recognised at this stage). The other problem with decorator is that I'm going to have to do interface method wrapping in every... single... decorator class. Bah. Which would you go for, if either? Or, if you can suggest some more elegant solution, that would be welcome. EDIT: It occurs to me that using the proposed ControlledGraph class with the strategy pattern may help here... some sort of template method / functors setup, with individual bits applying separate controls in the various graph-canonical interface methods. Or am I losing the plot?

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