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• Configuring log4net appenders via XML file *and* code

  - by Dave

  I started to play with log4net today and so far, I really like it. In order to preserve our current logging functionality, the app needs to create a new log file whenever the application is started. The log file name has the date and time stamp encoded in it. Currently, I've got log4net configured via an XmlConfigurator, which works great, except that the filename for my RollingFileAppender is hardcoded in the configuration XML file. I'd like to continue to use the XmlConfigurator, but after calling Configure(), I want to get at the RollingFileAppender and, in code, change its file value to be a dynamically-generated string. The sample documentation online seems to be down right now, but I've poked through the SDK reference, and it looks like I could use the Heirarchy and GetAppenders() to do what I need to do. Am I on the right track?

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• Fully customized login system in Django?

  - by user367817

  Hey, I am currently writing an application which I plan to sell as SaaS. Without giving away "secrets," I can say that it is basically a "document editing system" in which many users will be submitting documents. The basic heirarchy is this: Institution Individual Document Sub-document So each Individual should be able to BROWSE all documents that were submitted by anybody in their institution, but should only be able to EDIT documents that they created. No individual should even be aware of the existence of another Institution--that should all be completely hidden. I have written a Django/Python class that would facilitate this, but every document regarding authentication that I have read requires that I use the User object. Is this just a limitation of Django, or is there a way to do this? If there is a way, how can I get my own "Individual" class details attached to the "request" objects so I can validate the things I should be showing the users?

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• GUI system architecture?

  - by topright

  I'm designing GUI (graphical user interface) system for a game engine (C++). Idea is to create a heirarchy of GUI controllers like Focusable, Hoverable, Dragable etc. Every GUI component can attach multiple controllers, they modify component's behaviour. I think it gives flexible system and protects from code duplication. Different instances of the same GUI class can have different complex behaviours (may be, even change it dynamically), so this approach looks practical. The other choice is to add focused, hovered, dragged etc. flags in the base GUI component class. It looks like overhead and not that flexible. Another solution is to use Decorator pattern and wrap objects with FocusDecorator, HoverDecorator etc. Maintaining such system looks a bit harder. Question: What are pitfalls in my solution? May be you have seen a better approaches in GUI systems? What are the best ways of implementing such flexible complex system?

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• Why would a "view" object in Interface Builder prevent my didFinishLaunchingWithOptions method from

  - by BeachRunnerJoe

  You may have already come across some of my other questions related to question, but I was having an issue with a SplitView iPad app where my application:didFinishLaunchingWithOptions method stopped executing after I went into Interface Builder and changed around the structure of my apps interface. I couldn't figure out what was preventing my didFinishLauchingWithOptions method from executing, but then I removed a "view" object I had in my view heirarchy (shown below) and suddenly my didFinishLauchingWithOptions method started executing again. I've moved passed it now, but I'm still unclear why that would cause the problem. Any ideas why that "view" object would prevent the didFinishLaunchingWithOptions method from executing?

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• Django Template Inheritance -- Missing Images?

  - by user367817

  Howdy, I have got the following file heirarchy: project   other stuff   templates       images           images for site       app1           templates for app1       registration           login template       base.html (base for entire site)       style.css (for base.html) In the login template, I am extending 'base.html.' 'base.html' uses 'style.css' along with all of the images in the 'templates/images' directory. For some reason, none of the CSS styles or images will show up in the login template, even though I'm extending it. Does this missing image issue have something to do with screwed up "media" settings somewhere? I never understood those, but this is a major roadblock in my proof-of-concept, so any help is appreciated. Thanks!

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• Opinions sought on the best way to organise classes in PHP

  - by jax

  I am pretty much set on using the Java package naming convention of com.website.app.whatever but am unsure about the best way of doing this in PHP. Option 1: Create a directory structure com/ mysite/ myapp/ encryption/ PublicKeyGenerator.class.php Cipher.class.php Xml/ XmlHelper.class.php XmlResponse.class.php Now this is how Java does it, it uses the folders to organize the heirarchy. This is however a little clumsy in PHP because there is no native support for it and when you move things around you break all includes. Option 2 Name classes using a periods for the package, therefore sames are just like in Java but can all be in the same directory making __autoload a breeze. classes/ com.mysite.myapp.encription.PublicKeyGenerator.class.php com.mysite.myapp.encription.Cipher.class.php com.mysite.myapp.xml.XmlHelper.class.php com.mysite.myapp.xml.XmlResponse.class.php The only real disadvantage here is that all the classes are in a single folder which might be confusing for large projects. Opinions sought, which is the best or are there other even better options?

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• Page inheritance in mixed asp.net Forms and MVC application

  - by Rising Star

  I'm working on a web application. One of my co-workers has written some asp.net forms pages. The page classes all inherit from BasePageClass, which of course inherits from the Page class. I wish to add some MVC controllers that I've been told need to use the same logic implemented in the BasePageClass. Ordinarily, I would want to inherit the functions in the BasePageClass in the controller classes, but this breaks the inheritance heirarchy. What is the best practice for solving this problem?

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• Passing dependent objects to a parent constructor in Scala

  - by Nick Johnson

  Suppose I have the following class heirarchy: class A() class B(a:A) class C(b:B) class BaseClass(b:B, c:C) Now I want to implement a subclass of BaseClass, which is given an instance of A, and constructs instances of B and C, which it passes to its superclass constructor. If I could use arbitrary expressions, I'd do something like this: b = new B(a) c = new C(b) super(b, c) Because the second argument to the parent constructor depends on the value of the first argument, though, I can't see any way to do this, without using a factory function, or a gratuitous hack, such as : class IntermediateSubclass(b:B) extends BaseClass(b, new C(b)) class RealSubclass(a:A) extends IntermediateSubclass(new B(a)) Is there clean way to do this?

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• C# Event routing in code behind

  - by Nate

  I'm building a WPF MVVM-ish application. I want to be able to display an event log containing items in a collection that exists in my viewmodel. I want any of the objects in the model to be able to add data to the event log. Therefore every object needs to be able to pass data back to one central collection for databinding in the view. I could implement an event in every one of my data classes and manually pass the events up the object heirarchy but this seems super clumsy. On the visual tree a Routed Event would take care of this, is there some equivelent in the model scope? Any other ideas?

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• JSON is not nested in rails view

  - by SeanGeneva

  I have a several models in a heirarchy, 1:many at each level. Each class is associated only with the class above it and the one below it, ie: L1 course, L2 unit, L3 unit layout, L4 layout fields, L5 table fields (not in code, but a sibling of layout fields) I am trying to build a JSON response of the entire hierarchy. def show @course = Course.find(params[:id]) respond_to do |format| format.html # show.html.erb format.json do @course = Course.find(params[:id]) @units = @course.units.all @unit_layouts = UnitLayout.where(:unit_id => @units) @layout_fields = LayoutField.where(:unit_layout_id => @unit_layouts) response = {:course => @course, :units => @units, :unit_layouts => @unit_layouts, :layout_fields => @layout_fields} respond_to do |format| format.json {render :json => response } end end end end The code is bring back the correct values, but the units, unit_layouts and layout_fields are all nested at the same level under course. I would like them to be nested inside their parent.

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• Are static members inherited? (C++)

  - by Keand64

  When static members are inherited, are they static for the entire heirarchy, or just that class, ie: class SomeClass { public: SomeClass(){total++;} static int total; }; class SomeDerivedClass: public SomeClass { public: SomeDerivedClass(){total++;} }; int main() { SomeClass A; SomeClass B; SomeDerivedClass C; return 0; } would total be 3 in all three instances, or would it be 2 for SomeClass and 1 for SomeDerivedClass?

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• How is a constructor executed?

  - by simion

  I am doing some reviison from the lecture slides and it says a constructor is executed in the following way; If the constructor starts with this, recursively execute the indicated constructor, then go to step 4. Invoke the explicitly or implicitly indicated superclass constructor (unless this class is java.lang.Object) Initialise the fields of the object in the order in which they were declared in this class Execute the rest of the body of this constructor. What i dont undertsand is that, a constructor can never "start" with this, because even if it forms no class heirarchy/relationship then super() is inserted by default. How would this fit in with the description above? Thanks

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• Disk fragmentation when dealing with many small files

  - by Zorlack

  On a daily basis we generate about 3.4 Million small jpeg files. We also delete about 3.4 Million 90 day old images. To date, we've dealt with this content by storing the images in a hierarchical manner. The heriarchy is something like this: /Year/Month/Day/Source/ This heirarchy allows us to effectively delete days worth of content across all sources. The files are stored on a Windows 2003 server connected to a 14 disk SATA RAID6. We've started having significant performance issues when writing-to and reading-from the disks. This may be due to the performance of the hardware, but I suspect that disk fragmentation may be a culprit at well. Some people have recommended storing the data in a database, but I've been hesitant to do this. An other thought was to use some sort of container file, like a VHD or something. Does anyone have any advice for mitigating this kind of fragmentation? Additional Info: The average file size is 8-14KB Format information from fsutil: NTFS Volume Serial Number : 0x2ae2ea00e2e9d05d Version : 3.1 Number Sectors : 0x00000001e847ffff Total Clusters : 0x000000003d08ffff Free Clusters : 0x000000001c1a4df0 Total Reserved : 0x0000000000000000 Bytes Per Sector : 512 Bytes Per Cluster : 4096 Bytes Per FileRecord Segment : 1024 Clusters Per FileRecord Segment : 0 Mft Valid Data Length : 0x000000208f020000 Mft Start Lcn : 0x00000000000c0000 Mft2 Start Lcn : 0x000000001e847fff Mft Zone Start : 0x0000000002163b20 Mft Zone End : 0x0000000007ad2000

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• DirectX Desktop

  - by Jonathan

  Hi. I'd like to make an animated desktop background for Windows 7 using DirectX. I'm using C#, SlimDX and a couple of P/Invoke imports of Windows API functions. I'm not brilliant with native Windows programming, but I've had a poke around online and I believe what I need to do is either: 1) Find the handle of the window containing the dekstop wallpaper, hook it up to a DirectX device and draw into it. 2) Make a new output window, and insert it above the desktop wallpaper but below the desktop icons. I've tried both these, but neither seems to work. If I navigate the Window heirarchy starting from the handle returned by GetDesktopWindow(), I can go Desktop - WorkerW - SHELLDLL_DefView - SysListView32. If I hook up a DirectX device to this handle, I can draw over the entire desktop, but it also covers the icons. If I create a Windows form, set its parent to SHELLDLL_DefView using SetParent() and then use SetWindowPos to play with its Z-order I can only seem to get it to go either behind the desktop wallpaper or in front of the desktop + icons. It looks as though the desktop wallpaper is background to the folder view containing the icons, and therefore what I am trying to do cannot work. The only solution then would be to not use the desktop for icons, or to find some alternative, e.g. overwriting the desktop then overlaying a transparent window containing a view of the contents of some folder. Does anyone have any idea of what I should be doing, or even whether what I want to do is possible? It seems you can draw to the desktop background using the GDI (as I believe the wxSnow program does), and I've seen something similar to what I want done by VLC Media Player under Windows XP with its DirectX wallpaper mode (interestingly, I can't seem to get this option enabled on my system). Thanks!

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• python protobufs - avoid the install step ?

  - by orion elenzil

  i'm writing a small python utility which will be consumed by moderately non-technical users and which needs to interface w/ some protobufs. ideally, i would like the only prerequisites to using this on a local machine to be: have python installed * have an SVN checkout of the repository * run a simple bash script to build the local proto .py definitions * run "python myutility" i'm running into trouble around importing descriptor_pb2.py, tho. i've seen Why do I see "cannot import name descriptor_pb2" error when using Google Protocol Buffers? , but would like to avoid adding the additional prerequisite of having run the proto SDK installer. i've modified the bash script to also generate descriptor_pb2.py in the local heirarchy, which works for the first level of imports from my other _pb2.py files, but it looks like descriptor_pb2.py itself tries to import descriptor_pb2 can't find it: $ python myutility.py Traceback (most recent call last): File "myutility.py", line 4, in <module> import protos.myProto_pb2 File "/myPath/protos/myProto_pb2.py", line 8, in <module> from google.protobuf import descriptor_pb2 File "/myPath/google/protobuf/descriptor_pb2.py", line 8, in <module> from google.protobuf import descriptor_pb2 ImportError: cannot import name descriptor_pb2 my local folder looks like: * myutility.py * google/ * protobuf/ * descriptor.py * descriptor_pb2.py * protos * myProto_ob2.py also, i'm a python n00b, so it's possible i'm overlooking something obvious. tia, orion

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• Preserving hierarchy when converting .csv file to xml or json

  - by Simon Levinson

  Hello I have a question concerning translating data from a CSV into XML or JSON where it is essential to preserve the heirarchy of the data. For example, if I have CSV data like this: type,brand,country,quantity apple,golden_delicious,english,1 apple,golden_delicious,french,2 apple,cox,,4 apple,braeburn,,1 banana,,carribean,6 banana,,central_america,7 clememtine,,,3 What I want is to preserve hierarchy in the XML so that I get something like: <fruit> <type = "apple"> <brand = "golden_delicious"> <country = "english" quantity = "1"> <country = "french" quantity = "2"> </brand> <brand = "cox"> <quantity = "4"> </brand> <brand = "braeburn"> <quantity = "1"> </brand> </type> <type = "banana"> <country = "carribean" quantity = "6"> <country = "central_america" quantity = "7"> </type> <type = "clementine"> <quantity = "3"> </type> <fruit /> Is it best to try to use JAXP or to convert the above into a table simply of parent, child and then writing the data to an array of strings for processing,? Like this: parent,child fruit,apple apple,golden_delicious golden_delicious,english golden_delicious,french english,1 french,2 apple,cox cox,4 apple,braeburn braeburn,1 And so on. Or is there a better way? Thanks Simon Levinson

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• Temporary debug releases and final application releases

  - by baron

  I have a quick question regarding debug and release in VS 2008. I have an app i've been working on - its not yet complete but the bulk of the functionality is there. So basically i'm trying to give a copy of it now to the person helping with documentation - just so they can have a play and get the feel for what i've made. Now the question is how to provide it to them. I was told to just copy the .exe out of the debug/bin folder and put that onto USB. But when testing, if I run this .exe anywhere else (outside of this folder) it crashes. I've now worked out why this is: var path = ConfigurationManager.AppSettings["PathToUse"]; var files = Directory.GetFiles(path); throws a null reference, so that App.config file is not being used. If I copy that file in with the .exe it works again. So actually my question is regarding the best way to manage this situation. What is the best way to provide a working copy to people, and, is there a reference on preparing apps for release - so everything is packaged together and installed in a clean structured folder heirarchy?

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• .NET substitute dependent assemblies without recompiling?

  - by RK

  I have a question about how the .NET framework (2.0) resolves dependent assemblies. We're currently involved in a bit of a rewrite of a large ASP.NET application and various satellite executables. There are also some nagging problems with our foundation classes that we developed a new API to solve. So far this is a normal, albeit wide-reaching, update. Our heirarchy is: ASP.NET (aspx) business logic (DLLs) foundation classes (DLLs) So ASP.NET doesn't throw a fit, some of the DLLs (specifically the foundation classes) have a redirection layer that contains the old namespaces/functions and forwards them to the new API. When we replaced the DLLs, ASP.NET picked them up fine (probably because it triggered a recompile). Precompiled applications don't though, even though the same namespaces and classes are in both sets of DLLs. Even when the file is renamed, it complains about the assemblyname attribute being different (which it has to be by necessity). I know you can redirect to differnet versions of the same assembly, but is there any way to direct to a completely different assembly? The alternatives are to recompile the applications (don't really want to because the applications themselves haven't changed) or recompile the old foundation DLL with stubs refering to the new foundation DLL (the new dummy DLL is file system clutter).

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• Database design and foreign keys: Where should they be added in related tables?

  - by Carvell Fenton

  I have a relatively simple subset of tables in my database for tracking something called sessions. These are academic sessions (think offerings of a particular program). The tables to represent a sessions information are: sessions session_terms session_subjects session_mark_item_info session_marks All of these tables have their own primary keys, and are like a tree, in that sessions have terms, terms have subjects, subjects have mark items, etc. So each on would have at least its "parent's" foreign key. My question is, design wise is it a good idea to include the sessions primary key in the other tables as a foreign key to easily select related session items, or is that too much redundency? If I include the session foreign key (or all parent foreign keys from tables up the heirarchy) in all the tables, I can easily select all the marks for a session. As an example, something like SELECT mark FROM session_marks WHERE sessionID=... If I don't, then I would have to combine selects with something like WHERE something IN (SELECT... Which approach is "more correct" or efficient? Thanks in advance!

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• Type casting in C++ by detecting the current 'this' object type

  - by Elroy

  My question is related to RTTI in C++ where I'm trying to check if an object belongs to the type hierarchy of another object. The BelongsTo() method checks this. I tried using typeid, but it throws an error and I'm not sure about any other way how I can find the target type to convert to at runtime. #include <iostream> #include <typeinfo> class X { public: // Checks if the input type belongs to the type heirarchy of input object type bool BelongsTo(X* p_a) { // I'm trying to check if the current (this) type belongs to the same type // hierarchy as the input type return dynamic_cast<typeid(*p_a)*>(this) != NULL; // error C2059: syntax error 'typeid' } }; class A : public X { }; class B : public A { }; class C : public A { }; int main() { X* a = new A(); X* b = new B(); X* c = new C(); bool test1 = b->BelongsTo(a); // should return true bool test2 = b->BelongsTo(c); // should return false bool test3 = c->BelongsTo(a); // should return true } Making the method virtual and letting derived classes do it seems like a bad idea as I have a lot of classes in the same type hierarchy. Or does anybody know of any other/better way to the do the same thing? Please suggest.

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• Why is user asked to choose their workgroup?

  - by Clinton Blackmore

  We running Mac OS X Server 10.5.8 with Mac OS X 10.5.8 clients. Students use network logins to, well, log in. I've been asked to deny internet access to a specific user. I was told that a good way to do it is to create a user workgroup called "No Internet Access" and manage settings there. (Specifically, I told parental controls to allow access to no sites, and blacklisted all the installed web browsers). Now, when the user authenticates to log in, they are greeted with this dialog: Workgroups for <username> Grade 7 Students No Internet Access It is unlikely that the student would willing choose "No Internet Access" to be their base group. Looking in Workgroup Manager at the student's record, it shows their primary group ID is the grade 7 group, and "No Internet Access" is listed as another group they belong to. I looked at the managed preferences for all the computers pertaining to logins. They are set to their defaults. Specifically, the computer groups' preference for Logins - Access has the defaults: [unchecked] Ignore workgroup nesting [checked] Combine available workgroup settings Based on my reading of Tips and Tricks for Mac Administrators, this should be correct, the user should not be asked which group they belong to, and settings from all applicable groups should be applied. How can I achieve that result? Edit: I've decided to add some additional information from the Tips and Tricks for Mac Management White Paper (via Apple in Education, via the author's site). On page 21, it says: With Leopard MCX, workgroup preference settings are combined by default into a single set of values. This means that instead of having to choose between the Math, Science, or Language Arts workgroups when logging in, a user can just authenticate and be taken directly to the desktop. All the settings for each of those workgroups are composited together, providing you with all the Dock items and a composite of all the other settings. On page 40, an example is given in which settings are combined from different 'domains', one computer group, two (user) workgroups, and one individual user's settings. [When johnd logs into a leopard client,] the items staged in the Dock from left to right are: computer group, first workgroup alphabetically, second workgroup, user. Items within the workgroup are staged alphabetically. Nowhere is there an indication that groups are nested; indeed, I can see no sensible (non-flat) heirarchy for groups like Math, Science, and Language Arts. I strongly believe that there is a way to apply settings from two unrelated user workgroups such that a user of OS X 10.5.x or newer does not need to choose their workgroup. This is what I seek to achieve.

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• Timeout Expired error Using LINQ

  - by Refracted Paladin

  I am going to sum up my problem first and then offer massive details and what I have already tried. Summary: I have an internal winform app that uses Linq 2 Sql to connect to a local SQL Express database. Each user has there own DB and the DB stay in sync through Merge Replication with a Central DB. All DB's are SQL 2005(sp2or3). We have been using this app for over 5 months now but recently our users are getting a Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. Detailed: The strange part is they get that in two differnt locations(2 differnt LINQ Methods) and only the first time they fire in a given time period(~5mins). One LINQ method is pulling all records that match a FK ID and then Manipulating them to form a Heirarchy View for a TreeView. The second is pulling all records that match a FK ID and dumping them into a DataGridView. The only things I can find in common with the 2 are that the first IS an IEnumerable and the second converts itself from IQueryable - IEnumerable - DataTable... I looked at the query's in Profiler and they 'seemed' normal. They are not very complicated querys. They are only pulling back 10 - 90 records, from one table. Any thoughts, suggestions, hints whatever would be greatly appreciated. I am at my wit's end on this.... public IList<CaseNoteTreeItem> GetTreeViewDataAsList(int personID) { var myContext = MatrixDataContext.Create(); var caseNotesTree = from cn in myContext.tblCaseNotes where cn.PersonID == personID orderby cn.ContactDate descending, cn.InsertDate descending select new CaseNoteTreeItem { CaseNoteID = cn.CaseNoteID, NoteContactDate = Convert.ToDateTime(cn.ContactDate). ToShortDateString(), ParentNoteID = cn.ParentNote, InsertUser = cn.InsertUser, ContactDetailsPreview = cn.ContactDetails.Substring(0, 75) }; return caseNotesTree.ToList<CaseNoteTreeItem>(); } AND THIS ONE public static DataTable GetAllCNotes(int personID) { using (var context = MatrixDataContext.Create()) { var caseNotes = from cn in context.tblCaseNotes where cn.PersonID == personID orderby cn.ContactDate select new { cn.ContactDate, cn.ContactDetails, cn.TimeSpentUnits, cn.IsCaseLog, cn.IsPreEnrollment, cn.PresentAtContact, cn.InsertDate, cn.InsertUser, cn.CaseNoteID, cn.ParentNote }; return caseNotes.ToList().CopyLinqToDataTable(); } }

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• Why does the rename() syscall prohibit moving a directory that I can't write to a different director

  - by Daniel Papasian

  I am trying to understand why this design decision was made with the rename() syscall in 4.2BSD. There's nothing I'm trying to solve here, just understand the rationale for the behavior itself. 4.2BSD saw the introduction of the rename() syscall for the purpose of allowing atomic renames/moves of files. From 4.3BSD-Reno/src/sys/ufs/ufs_vnops.c: /* * If ".." must be changed (ie the directory gets a new * parent) then the source directory must not be in the * directory heirarchy above the target, as this would * orphan everything below the source directory. Also * the user must have write permission in the source so * as to be able to change "..". We must repeat the call * to namei, as the parent directory is unlocked by the * call to checkpath(). */ if (oldparent != dp->i_number) newparent = dp->i_number; if (doingdirectory && newparent) { VOP_LOCK(fndp->ni_vp); error = ufs_access(fndp->ni_vp, VWRITE, tndp->ni_cred); VOP_UNLOCK(fndp->ni_vp); So clearly this check was added intentionally. My question is - why? Is this behavior supposed to be intuitive? The effect of this is that one cannot move a directory (located in a directory that one can write) that one cannot write to another directory that one can write to atomically. You can, however, create a new directory, move the links over (assuming one has read access to the directory), and then remove one's write bit on the directory. You just can't do so atomically. % cd /tmp % mkdir stackoverflow-question % cd stackoverflow-question % mkdir directory-1 % mkdir directory-2 % mkdir directory-1/directory-i-cant-write % echo "foo" > directory-1/directory-i-cant-write/contents % chmod 000 directory-1/directory-i-cant-write/contents % chmod 000 directory-1/directory-i-cant-write % mv directory-1/directory-i-cant-write directory-2 mv: rename directory-1/directory-i-cant-write to directory-2/directory-i-cant-write: Permission denied We now have a directory I can't write with contents I can't read that I can't move atomically. I can, however, achieve the same effect non-atomically by changing permissions, making the new directory, using ln to create the new links, and changing permissions. (Left as an exercise to the reader) . and .. are special cased already, so I don't particularly buy that it is intuitive that if I can't write a directory I can't "change .." which is what the source suggests. Is there any reason for this besides it being the perceived correct behavior by the author of the code? Is there anything bad that can happen if we let people atomically move directories (that they can't write) between directories that they can write?

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• How to pass operators as parameters

  - by Rodion Ingles

  I have to load an array of doubles from a file, multiply each element by a value in a table (different values for different elements), do some work on it, invert the multiplication (that is, divide) and then save the data back to file. Currently I implement the multiplication and division process in two separate methods. Now there is some extra work behind the scenes but apart from the specific statements where the multiplication/division occurs, the rest of the code is identical. As you can imagine, with this approach you have to be very careful making any changes. The surrounding code is not trivial, so its either a case of manually editing each method or copying changes from one method to the other and remembering to change the * and / operators. After too many close calls I am fed up of this and would like to make a common function which implements the common logic and two wrapper functions which pass which operator to use as a parameter. My initial approach was to use function pointers: MultiplyData(double data) { TransformData(data, &(operator *)); } DivideData(double data) { TransformData(data, &(operator /)); } TransformData(double data, double (*func)(double op1, double op2)) { /* Do stuff here... */ } However, I can't pass the operators as pointers (is this because it is an operator on a native type?), so I tried to use function objects. Initially I thought that multiplies and divides functors in <functional> would be ideal: MultiplyData(double data) { std::multiplies<double> multFunct; TransformData(data, &multFunct); } DivideData(double data) { std::divides<double> divFunct; TransformData(data, &divFunct); } TransformData(double data, std::binary_function<double, double, double> *funct) { /* Do stuff here... */ } As you can see I was trying to use a base class pointer to pass the functor polymorphically. The problem is that std::binary_function does not declare an operator() member for the child classes to implement. Is there something I am missing, or is the solution to implement my own functor heirarchy (which really seems more trouble than it is worth)?

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• 'Timeout Expired' error against local SQL Express on only 2 LINQ Methods...

  - by Refracted Paladin

  I am going to sum up my problem first and then offer massive details and what I have already tried. Summary: I have an internal winform app that uses Linq 2 Sql to connect to a local SQL Express database. Each user has there own DB and the DB stay in sync through Merge Replication with a Central DB. All DB's are SQL 2005(sp2or3). We have been using this app for over 5 months now but recently our users are getting a Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. Detailed: The strange part is they get that in two differnt locations(2 differnt LINQ Methods) and only the first time they fire in a given time period(~5mins). One LINQ method is pulling all records that match a FK ID and then Manipulating them to form a Heirarchy View for a TreeView. The second is pulling all records that match a FK ID and dumping them into a DataGridView. The only things I can find in common with the 2 are that the first IS an IEnumerable and the second converts itself from IQueryable - IEnumerable - DataTable... I looked at the query's in Profiler and they 'seemed' normal. They are not very complicated querys. They are only pulling back 10 - 90 records, from one table. Any thoughts, suggestions, hints whatever would be greatly appreciated. I am at my wit's end on this.... public IList<CaseNoteTreeItem> GetTreeViewDataAsList(int personID) { var myContext = MatrixDataContext.Create(); var caseNotesTree = from cn in myContext.tblCaseNotes where cn.PersonID == personID orderby cn.ContactDate descending, cn.InsertDate descending select new CaseNoteTreeItem { CaseNoteID = cn.CaseNoteID, NoteContactDate = Convert.ToDateTime(cn.ContactDate). ToShortDateString(), ParentNoteID = cn.ParentNote, InsertUser = cn.InsertUser, ContactDetailsPreview = cn.ContactDetails.Substring(0, 75) }; return caseNotesTree.ToList<CaseNoteTreeItem>(); } AND THIS ONE public static DataTable GetAllCNotes(int personID) { using (var context = MatrixDataContext.Create()) { var caseNotes = from cn in context.tblCaseNotes where cn.PersonID == personID orderby cn.ContactDate select new { cn.ContactDate, cn.ContactDetails, cn.TimeSpentUnits, cn.IsCaseLog, cn.IsPreEnrollment, cn.PresentAtContact, cn.InsertDate, cn.InsertUser, cn.CaseNoteID, cn.ParentNote }; return caseNotes.ToList().CopyLinqToDataTable(); } }

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