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  • Rolling Back a Transaction with MySQL Connector in VB.net

    - by Jonathan
    Hey all- I have one multi-row INSERT statement (300 or so sets of values) that I would like to commit to the MySQL database in an all-or-nothing fashion. insert into table VALUES (1, 2, 3), (4, 5, 6), (7, 8, 9); In some cases, a set of values in the command will not meet the criteria of the table (duplicate key, for example). When that happens I do not want any of the previous sets added to the database. I've implemented this with the following code, however, my rollback command doesn't appear to be making a difference. I've used this documentation: http://dev.mysql.com/doc/refman/5.0/es/connector-net-examples-mysqltransaction.html Dim transaction As MySqlTransaction = sqlConnection.BeginTransaction() sqlCommand = New MySqlCommand(insertStr, sqlConnection, transaction) Try sqlCommand.ExecuteNonQuery() Catch ex As Exception writeToLog("EXCEPTION: " & ex.Message & vbNewLine) writeToLog("Could not execute " & sqlCmd & vbNewLine) Try transaction.Rollback() writeToLog("All statements were rolled back." & vbNewLine) Return False Catch rollbackEx As Exception writeToLog("EXCEPTION: " & rollbackEx.Message & vbNewLine) writeToLog("All statements were not rolled back." & vbNewLine) Return False End Try End Try transaction.commit() I get the DUPLICATE KEY exception thrown, no Rollback Exception thrown, and every set of values up to duplicate key committed to the database. What am I doing wrong? Thanks- Jonathan

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  • Obtaining touch location for a uiscrollview touch

    - by LOSnively
    I have a uiscrollview as an element of a uiscrollviewcontroller, along with other view objects. The image scrolls and zooms as expected, when the scrollView is the top subview. However, I also need to get the screen location of the touch, in particular when there is no scroll action. (I understand the location may change during a scroll, but that's not important.) I haven't found a way to do that. In the scrollviewcontroller implementation I have customized all of the standard methods that should do this: "touchesShouldBegin...", "touchesBegan:...", "touchesEnded:...", and so on. As far as I can tell, none of these are being called during a touch event when the scrollView is the top subview. I've tried setting the delayContentTouches property to both YES and NO, and that doesn't seem to make a difference. As an alternative, I've tried putting a UIView as the top subview and then tried passing the touches to the now underlying scrollView. In this configuration, the standard methods are called and I can get the touch location, but I haven't found a mechanism for the touches to be passed to the scrollView so scrolling occurs. Doing something like sending the touch messages to the specific scrollView, or to "super" or just sending them to nextResponder doesn't do it. It seems I can make the scroll work or find the location of the touch but not both, depending on what the "top" subview is. I suspect this is trivial, but after two weeks of struggling, it's time to eat my embarrassment for not being able to do this seemingly simplest of things. I've read all of the related questions here on stackoverflow, tried most if not all of the suggestions, and so far, nothing has worked. I've looked through the various links and references suggested by the answers, including Apple's documentation, but none have pointed out the gap in my understanding. Any ideas would be appreciated.

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  • What do these errors mean? ISOC++ forbids assignment of arrays...

    - by xunlinkx
    I'm trying to compile some code on one of our systems for our DBA...I've edited the makefiles to include the pertinent libraries listed in the documentation, but I keep getting these errors... Can you discern any obvious problems from my command lines in reference to the errors listed? Thank you! make -f /u01/app/banner/ban8/TEST3/links/Makefile_tm_linux64_redhat5_ban8.mk gcc -m64 -D_NOFIXARGPTR -fpic -shared -DTMCILIB_EXPORTS -D_TMUNICODE -I/usr/local/ban_icu -I/usr/local/src/icu/source/i18n/ -I/usr/local/src/icu/source/common/ -I/usr/local/src/icu/source/extra/ustdio/ -I/usr/local/src/icu/source/io -L/usr/lib64 -L/usr/lib -L/usr/local/src/icu/source/data/ -L/usr/local/src/icu/source/data/out/ -L/usr/local/src/icu/source/tools/toolutil/ -L/usr/lib/im/icuconv/ -L/usr/local/lib/ -L. -licui18n -licudata -licuuc -licu-toolutil -licuio msgfmttm.cpp umsgtm.cpp tmcilib.cpp -o /u01/app/banner/ban8/TEST3/general/exe/libtmciuc.so umsgtm.cpp: In function ‘void fixArgPtr(const UChar*, __va_list_tag (*)[1])’: umsgtm.cpp:158: error: array must be initialized with a brace-enclosed initializer umsgtm.cpp:194: error: ISO C++ forbids assignment of arrays umsgtm.cpp: In function ‘int32_t tmumsg_vformat(void*, UChar, int32_t, __va_list_tag*, UErrorCode*)’: umsgtm.cpp:305: error: cannot convert ‘__va_list_tag**’ to ‘__va_list_tag ()[1]’ for argument ‘2’ to ‘void fixArgPtr(const UChar, __va_list_tag (*)[1])’ tmcilib.cpp: In function ‘int tmprintf(TMBundle*, const UChar*, ...)’: tmcilib.cpp:743: error: array must be initialized with a brace-enclosed initializer tmcilib.cpp: In function ‘int tmfprintf(TMBundle*, UFILE*, const UChar*, ...)’: tmcilib.cpp:757: error: array must be initialized with a brace-enclosed initializer tmcilib.cpp: In function ‘int tmsprintf(TMBundle*, UChar*, const UChar*, ...)’: tmcilib.cpp:808: error: array must be initialized with a brace-enclosed initializer

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  • possible xml elements in Android resources xmls ?

    - by Vijay C
    I recently came across a forum post in thelink text android developers group. (link below) It has one post which contains following xml. It is xml file which can be used in drawable folder. <selector xmlns:android="http://schemas.android.com/apk/res/android"> <!-- Non focused states --> <item android:state_focused="false" android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/tab_unselected" /> <item android:state_focused="false" android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/tab_selected" /> <!-- Focused states --> <item android:state_focused="true" android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/tab_focus" /> <item android:state_focused="true" android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/tab_focus"/> <!-- Pressed --> <item android:state_pressed="true" android:drawable="@drawable/tab_press" /> </selector> Now my question is, where is the documentation which tells me that i can use the following xml tags <selector> , <item>, <color>, <integer-array>, <string-array> and many others tag to create xml resources...? I hope, i have explained what i want to know ?

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  • ShSetFolderPath works on win7, doesn't on XP

    - by pipboy3k
    Hey. I'm trying to use ShSetFolderPath function in C#. I work on Win7, I've managed to use ShSetKnownFolderPath and it works fine. Since this function is unavaible in WinXP, i tried to invoke ShSetFolderPath. Because i'm not familiar with invoking, I've done some searching and found something on some French forum. I don't speak French, but this declaration makes sense (as written in Remarks of function documentation in MSDN library): [DllImport( "Shell32.dll", CharSet = CharSet.Unicode, EntryPoint = "#232" ) ] private static extern int SHSetFolderPath( int csidl, IntPtr hToken, uint flags, string path ); I call it like that: private static int CSIDL_DESKTOP = 0x0000; public static void SetDesktopPath(string path) { int ret; ret = SHSetFolderPath(CSIDL_DESKTOP, IntPtr.Zero, 0, path); if (ret != 0) { Console.WriteLine(ret); Console.WriteLine(Marshal.GetExceptionForHR(ret)); } } It works in Win7, but in XP function returns -2147024809, which means "Value does not fall within the expected range". My guess is, it's something wrong with Dll importing. Any idea?

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  • Why won't my program terminate?

    - by Qwertie
    I have a .NET Compact Framework app that can runs on three windows machines (Desktop windows and two WinCE machines) and on the WinCE devices, the process never terminates on exit, even if I call Application.Exit(). Besides .NET, it uses one COM component (which does everything on the UI thread). If I break into the debugger after exitting, Visual Studio shows only one thread and a completely blank call stack. What could possibly cause this? Update: My process is terminating on the desktop but not the WinCE machines. I tried to force the process to terminate with the following code, but it doesn't work: [DllImport("coredll.dll")] static extern int TerminateProcess(IntPtr hProcess, uint uExitCode); static public void ExitProcess() { if (Platform.IsWindowsCE) TerminateProcess(new IntPtr(-1), 0); Application.Exit(); } There are also supposed to be ExitProcess() and GetCurrentProcess() APIs like the following, but if I try to call them, I get EntryPointNotFoundException. Therefore I am using TerminateProcess(-1, 0) because the documentation for the desktop version of GetCurrentProcess claims that it simply returns -1. [DllImport("coredll.dll")] static extern int ExitProcess(IntPtr hProcess); [DllImport("coredll.dll")] static extern IntPtr GetCurrentProcess(); Even if I do this: static public void ExitProcess() { if (Platform.IsWindowsCE) TerminateProcess(new IntPtr(-1), 0); Application.Exit(); throw new Exception("Trying to force quit."); } A fatal error dialog appears with a helpful "Quit" button, but pushing the button still does not cause the process to terminate on either machine!

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  • How do I represent concurrent actions in jBPM, any of which can end a process?

    - by tpdi
    An example: a permit must be examined by two lawyers and one engineer. If any of those three reject it, the process enters a "rejected" end state. If all three grant the permit, it enters a "granted" end state. All three examiners may examine simultaneously, or in any order. Once one engineer has granted it, it shouldn't be available to be examined by an engineer; once two lawyers have examined it, it shouldn't be available to lawyers; once one engineer and two lawyers have examined it should go to the granted end state. My initial thinking is that either I have a overly complicated state transition diagram, with "the same" intermediate states multiply repeated, or I carry (external) state with the process { bool rejected; int engineerSignoffId; int lawyer1SignoffId; int lawyer2SignoffId}. Or something like this? If so, how does the engineer's rejection terminate the subprocess that is in "Lawyers"? START->FORK->Engineer->Granted?---------------->Y->JOIN-->Granted |->Lawyers-->Granted?->by 2 lawyers?->Y---^ ^ | |--------------------------N What's the canonical jBPM answer to this? Can you point me to examples or documentation of such answers? Thanks.

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  • How can I sync files in two different git repositories (not clones) and maintain history?

    - by brian d foy
    I maintain two different git repos that need to share some files, and I'd like the commits in one repo to show up in the other. What's a good way to do that for ongoing maintenance? I've been one of the maintainers of the perlfaq (Github), and recently I fell into the role of maintaining the Perl core documentation, which is also in git. Long before I started maintaining the perlfaq, it lived in a separate source control repository. I recently converted that to git. Periodically, one of the perl5-porters would sync the shared files in the perlfaq repo and the perl repo. Since we've switched to git, we'e been a bit lazy converting the tools, and I'm now the one who does that. For the time being, the two repos are going to stay separate. Currently, to sync the FAQ for a new (monthly) release of perl, I'm almost ashamed to say that I merely copy the perlfaq*.pod files in the perlfaq repo and overlay them in the perl repo. That loses history, etc. Additionally, sometimes someone makes a change to those files in the perl repo and I end up overwriting it (yes, check git diff you idiot!). The files do not have the same paths in the repo, but that's something that I could change, I think. What I'd like to do, in the magical universe of rainbows and ponies, is pull the objects from the perlfaq repo and apply them in the perl repo, and vice-versa, so the history and commit ids correspond in each. Creating patches works, but it's also a lot work to manage it Git submodules seem to only work to pull in the entire external repo I haven't found something like svn's file externals, but that would work in both directions anyway I'd love to just fetch objects from one and cherry-pick them in the other What's a good way to manage this?

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  • How to make a custom NSFormatter work correctly on Snow Leopard?

    - by Nathan
    I have a custom NSFormatter attached to several NSTextFields who's only purpose is to uppercase the characters as they are typed into field. The entire code for my formatter is included below. The stringForObjectValue() and getObjectValue() implementations are no-ops and taken pretty much directly out of Apple's documentation. I'm using the isPartialStringValid() method to return an uppercase version of the string. This code works correctly in 10.4 and 10.5. When I run it on 10.6, I get "strange" behaviour where text fields aren't always render the characters that are typed and sometimes are just displaying garbage. I've tried enabling NSZombie detection and running under Instruments but nothing was reported. I see errors like the following in "Console": HIToolbox: ignoring exception '*** -[NSCFString replaceCharactersInRange:withString:]: Range or index out of bounds' that raised inside Carbon event dispatch ( 0 CoreFoundation 0x917ca58a __raiseError + 410 1 libobjc.A.dylib 0x94581f49 objc_exception_throw + 56 2 CoreFoundation 0x917ca2b8 +[NSException raise:format:arguments:] + 136 3 CoreFoundation 0x917ca22a +[NSException raise:format:] + 58 4 Foundation 0x9140f528 mutateError + 218 5 AppKit 0x9563803a -[NSCell textView:shouldChangeTextInRange:replacementString:] + 852 6 AppKit 0x95636cf1 -[NSTextView(NSSharing) shouldChangeTextInRanges:replacementStrings:] + 1276 7 AppKit 0x95635704 -[NSTextView insertText:replacementRange:] + 667 8 AppKit 0x956333bb -[NSTextInputContext handleTSMEvent:] + 2657 9 AppKit 0x95632949 _NSTSMEventHandler + 209 10 HIToolbox 0x93379129 _ZL23DispatchEventToHandlersP14EventTargetRecP14OpaqueEventRefP14HandlerCallRec + 1567 11 HIToolbox 0x933783f0 _ZL30SendEventToEventTargetInternalP14OpaqueEventRefP20OpaqueEventTargetRefP14HandlerCallRec + 411 12 HIToolbox 0x9339aa81 SendEventToEventTarget + 52 13 HIToolbox 0x933fc952 SendTSMEvent + 82 14 HIToolbox 0x933fc2cf SendUnicodeTextAEToUnicodeDoc + 700 15 HIToolbox 0x933fbed9 TSMKeyEvent + 998 16 HIToolbox 0x933ecede TSMProcessRawKeyEvent + 2515 17 AppKit 0x95632228 -[NSTextInputContext handleEvent:] + 1453 18 AppKit 0x9562e088 -[NSView interpretKeyEvents:] + 209 19 AppKit 0x95631b45 -[NSTextView keyDown:] + 751 20 AppKit 0x95563194 -[NSWindow sendEvent:] + 5757 21 AppKit 0x9547bceb -[NSApplication sendEvent:] + 6431 22 AppKit 0x9540f6fb -[NSApplication run] + 917 23 AppKit 0x95407735 NSApplicationMain + 574 24 macsetup 0x00001f9f main + 24 25 macsetup 0x00001b75 start + 53 ) Can anybody shed some light on what is happening? Am I just using NSFormatter incorrectly? -(NSString*) stringForObjectValue:(id)object { if( ![object isKindOfClass: [ NSString class ] ] ) { return nil; } return [ NSString stringWithString: object ]; } -(BOOL)getObjectValue: (id*)object forString: string errorDescription:(NSString**)error { if( object ) { *object = [ NSString stringWithString: string ]; return YES; } return NO; } -(BOOL) isPartialStringValid: (NSString*) cStr newEditingString: (NSString**) nStr errorDescription: (NSString**) error { *nStr = [NSString stringWithString: [cStr uppercaseString]]; return NO; }

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  • How to properly force a Blackberry Java application to install using Loader.exe

    - by Kevin White
    I want to include the Application Loader process in a software installation, to ensure that users get our software installed on their Blackberry by the time our installer software finishes. I know this is possible, because Aerize Card Loader (http://aerize.com/blackberry/software/loader/) does this. When you install their software, if your Blackberry is connected the Application Loader will come up and force the .COD file to install to the device. I can't make it work. Looking at RIM's own documentation, I need to: Place the ALX and COD files into a subfolder here: C:\Program Files\Common Files\Research In Motion\Shared\Applications\ Add a path to the ALX file in HKCU\Software\Research In Motion\Blackberry\Loader\Packages Index the application, by executing this at the command line: loader.exe /index Start the force load, by doing this: loader.exe /defaultUSB /forceload When I execute that last command, the Application Loader comes up and says that all applications are up to date and nothing needs to be done. If I execute loader.exe by double-clicking on it (or typing in the command with no parameters), I get the regular Application Loader wizard. It shows my program as listed, but un-checked. If I check it and click next, it will install to the Blackberry. (This is the part that I want to avoid, and that Aerize Card Loader's install process avoids.) What am I missing? It appears that the Aerize installer is doing something different but I haven't been able to ascertain what.

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  • Spring upload file

    - by benaissa
    hi every one, I'm a novice in Spring, i started to develop an application to upload files,i used the official spring documentation but, i have this error: Handler processing failed; nested exception is java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:823) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:143) 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:127) 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:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream at org.apache.commons.fileupload.disk.DiskFileItemFactory.createItem(DiskFileItemFactory.java:191) at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:350) at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:126) at org.springframework.web.multipart.commons.CommonsMultipartResolver.parseRequest(CommonsMultipartResolver.java:155) at org.springframework.web.multipart.commons.CommonsMultipartResolver.resolveMultipart(CommonsMultipartResolver.java:138) at org.springframework.web.servlet.DispatcherServlet.checkMultipart(DispatcherServlet.java:907) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:750)

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  • WCF done broke.

    - by SteveCav
    WCF is completely fouled up on my machine. I start a new sln in VS2008. Add a project (WCF Service Lib).Build the project (builds ok). debug the project -- it gets halfway through the progress bar and bombs out with the error below (real path changed to "my mex path" so codeproject doesn't think its spam). I'm assuming it's file permissions but don't know where to start. Any ideas?: Error: Cannot obtain Metadata from my mex path If this is a Windows (R) Communication Foundation service to which you have access, please check that you have enabled metadata publishing at the specified address. For help enabling metadata publishing, please refer to the MSDN documentation at somewhere unhelpful Exchange Error URI: my mex path Metadata contains a reference that cannot be resolved: 'my mex path'. Could not connect to my mex path. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:8731. Unable to connect to the remote server No connection could be made because the target machine actively refused it 127.0.0.1:8731HTTP GET Error URI: my mex path There was an error downloading 'my mex path'. Unable to connect to the remote server No connection could be made because the target machine actively refused it 127.0.0.1:8731

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  • Is there a disassembler + debugger for java (ala OllyDbg / SoftICE for assembler)?

    - by Ran Biron
    Is there a utility similar to OllyDbg / SoftICE for java? I.e. execute class (from jar / with class path) and, without source code, show the disassembly of the intermediate code with ability to step through / step over / search for references / edit specific intermediate code in memory / apply edit to file... If not, is it even possible to write something like this (assuming we're willing to live without hotspot for the debug duration)? Edit: I'm not talking about JAD or JD or Cavaj. These are fine decompilers, but I don't want a decompiler for several reasons, most notable is that their output is incorrect (at best, sometimes just plain wrong). I'm not looking for a magical "compiled bytes to java code" - I want to see the actual bytes that are about to be executed. Also, I'd like the ability to change those bytes (just like in an assembly debugger) and, hopefully, write the changed part back to the class file. Edit2: I know javap exists - but it does only one way (and without any sort of analysis). Example (code taken from the vmspec documentation): From java code, we use "javac" to compile this: void setIt(int value) { i = value; } int getIt() { return i; } to a java .class file. Using javap -c I can get this output: Method void setIt(int) 0 aload_0 1 iload_1 2 putfield #4 5 return Method int getIt() 0 aload_0 1 getfield #4 4 ireturn This is OK for the disassembly part (not really good without analysis - "field #4 is Example.i"), but I can't find the two other "tools": A debugger that goes over the instructions themselves (with stack, memory dumps, etc), allowing me to examine the actual code and environment. A way to reverse the process - edit the disassembled code and recreate the .class file (with the edited code).

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  • Encryption puzzle / How to create a ProxyStub for a Remote Assistance ticket

    - by Jon Clegg
    I am trying to create a ticket for Remote Assistance. Part of that requires creating a PassStub parameter. As of the documenation: http://msdn.microsoft.com/en-us/library/cc240115(PROT.10).aspx PassStub: The encrypted novice computer's password string. When the Remote Assistance Connection String is sent as a file over e-mail, to provide additional security, a password is used.<16 In part 16 they detail how to create as PassStub. In Windows XP and Windows Server 2003, when a password is used, it is encrypted using PROV_RSA_FULL predefined Cryptographic provider with MD5 hashing and CALG_RC4, the RC4 stream encryption algorithm. As PassStub looks like this in the file: PassStub="LK#6Lh*gCmNDpj" If you want to generate one yourself run msra.exe in Vista or run the Remote Assistance tool in WinXP. The documentation says this stub is the result of the function CryptEncrypt with the key derived from the password and encrypted with the session id (Those are also in the ticket file). The problem is that CryptEncrypt produces a binary output way larger then the 15 byte PassStub. Also the PassStub isn't encoding in any way I've seen before. Some interesting things about the PassStub encoding. After doing statistical analysis the 3rd char is always a one of: !#$&()+-=@^. Only symbols seen everywhere are: *_ . Otherwise the valid characters are 0-9 a-z A-Z. There are a total of 75 valid characters and they are always 15 bytes. Running msra.exe with the same password always generates a different PassStub, indicating that it is not a direct hash but includes the rasessionid as they say. Some other ideas I've had is that it is not the direct result of CryptEncrypt, but a result of the rasessionid in the MD5 hash. In MS-RA (http://msdn.microsoft.com/en-us/library/cc240013(PROT.10).aspx). The "PassStub Novice" is simply hex encoded, and looks to be the right length. The problem is I have no idea how to go from any hash to way the ProxyStub looks like.

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  • Find all cycles in graph, redux

    - by Shadow
    Hi, I know there are a quite some answers existing on this question. However, I found none of them really bringing it to the point. Some argue that a cycle is (almost) the same as a strongly connected components (s. http://stackoverflow.com/questions/546655/finding-all-cycles-in-graph/549402#549402) , so one could use algorithms designed for that goal. Some argue that finding a cycle can be done via DFS and checking for back-edges (s. boost graph documentation on file dependencies). I now would like to have some suggestions on whether all cycles in a graph can be detected via DFS and checking for back-edges? My opinion is that it indeed could work that way as DFS-VISIT (s. pseudocode of DFS) freshly enters each node that was not yet visited. In that sense, each vertex exhibits a potential start of a cycle. Additionally, as DFS visits each edge once, each edge leading to the starting point of a cycle is also covered. Thus, by using DFS and back-edge checking it should indeed be possible to detect all cycles in a graph. Note that, if cycles with different numbers of participant nodes exist (e.g. triangles, rectangles etc.), additional work has to be done to discriminate the acutal "shape" of each cycle.

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  • Can a class inherit from LambdaExpression in .NET? Or is this not recommended?

    - by d.
    Consider the following code (C# 4.0): public class Foo : LambdaExpression { } This throws the following design-time error: Foo does not implement inherited abstract member System.Linq.Expressions.LambdaExpression.Accept(System.Linq.Expressions.Compiler.StackSpiller) There's absolutely no problem with public class Foo : Expression { } but, out of curiosity and for the sake of learning, I've searched in Google System.Linq.Expressions.LambdaExpression.Accept(System.Linq.Expressions.Compiler.StackSpiller) and guess what: zero results returned (when was the last time you saw that?). Needless to say, I haven't found any documentation on this method anywhere else. As I said, one can easily inherit from Expression; on the other hand LambdaExpression, while not marked as sealed (Expression<TDelegate> inherits from it), seems to be designed to prevent inheriting from it. Is this actually the case? Does anyone out there know what this method is about? EDIT (1): More info based on the first answers - If you try to implement Accept, the editor (C# 2010 Express) automatically gives you the following stub: protected override Expression Accept(System.Linq.Expressions.ExpressionVisitor visitor) { return base.Accept(visitor); } But you still get the same error. If you try to use a parameter of type StackSpiller directly, the compiler throws a different error: System.Linq.Expressions.Compiler.StackSpiller is inaccessible due to its protection level. EDIT (2): Based on other answers, inheriting from LambdaExpression is not possible so the question as to whether or not it is recommended becomes irrelevant. I wonder if, in cases like this, the error message should be Foo cannot implement inherited abstract member System.Linq.Expressions.LambdaExpression.Accept(System.Linq.Expressions.Compiler.StackSpiller) because [reasons go here]; the current error message (as some answers prove) seems to tell me that all I need to do is implement Accept (which I can't do).

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  • correcting fisheye distortion programmatically

    - by Will
    I have some points that describe positions in a picture taken with a fisheye lens. I've found this description of how to generate a fisheye effect, but not how to reverse it. How do you calculate the radial distance from the centre to go from fisheye to rectilinear? My function stub looks like this: Point correct_fisheye(const Point& p,const Size& img) { // to polar const Point centre = {img.width/2,img.height/2}; const Point rel = {p.x-centre.x,p.y-centre.y}; const double theta = atan2(rel.y,rel.x); double R = sqrt((rel.x*rel.x)+(rel.y*rel.y)); // fisheye undistortion in here please //... change R ... // back to rectangular const Point ret = Point(centre.x+R*cos(theta),centre.y+R*sin(theta)); fprintf(stderr,"(%d,%d) in (%d,%d) = %f,%f = (%d,%d)\n",p.x,p.y,img.width,img.height,theta,R,ret.x,ret.y); return ret; } Alternatively, I could somehow convert the image from fisheye to rectilinear before finding the points, but I'm completely befuddled by the OpenCV documentation. Is there a straightforward way to do it in OpenCV, and does it perform well enough to do it to a live video feed?

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  • Initial text and paperclipped-URL for action in UIActivityViewController & UIActivityItemSource?

    - by Benjamin Kreeger
    Finally been making it through Apple's (rather dismal) documentation on the new UIActivityViewController class and the UIActivityItemSource protocol, and I'm trying to send different data sets to different actions called from the activity view. To simplify things, I'm looking at two things. A Facebook posting action, which should say "Check this out!" and also attach a URL to the post (with that cute little paperclip). A Twitter posting action, which should say "Check this out, with #hashtag!" and also attach that same URL (with the same paperclip). Here's the code I've got implemented right now. - (id)activityViewController:(UIActivityViewController *)activityViewController itemForActivityType:(NSString *)activityType { if ([activityType isEqualToString:UIActivityTypePostToFacebook]) { return @"Check this out!"; } else if ([activityType isEqualToString:UIActivityTypePostToTwitter]) { return @"Check this out, with #hashtag!"; } return @""; } - (id)activityViewControllerPlaceholderItem:(UIActivityViewController *)activityViewController { return @""; } And then when I set up this activity view controller (it's in the same class), this is what I do. UIActivityViewController *activityView = [[UIActivityViewController alloc] initWithActivityItems:@[self] applicationActivities:nil]; [self presentViewController:activityView animated:YES completion:nil]; My dilemma is how to attach that NSURL object. It's relatively easy when calling the iOS 6 SL-class posting modals; you just call the individual methods to attach a URL or an image. How would I go about doing this here? I'll note that instead of returning NSString objects from -activityViewController:itemForActivityType, if I return just NSURL objects, they show up with that paperclip, with no body text in the post. If I return an array of those two items, nothing shows up at all.

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  • How do I create self-relationships in polymorphic inheritance in Elixir and Pylons?

    - by Turukawa
    I am new to programming and am following the example in the Pylons documentation on creating a Wiki. The database I want to link to the wiki was created with Elixir so I rewrote the Wiki database schema and have continued from there. In the wiki there is a requirement for a Navigation table which is inherited by Pages and Sections. A section can have many pages, while a page can only have one section. In addition, each sibling node can be chain-referenced to each other. So: Nav has "section" (OneToMany) and "before" (OneToOne - to reference preceeding node) Page has "section" (ManyToOne - many pages in one section) and inherits "before" Section inherits all from Nav The code I've written looks like this: class Nav(Entity): using_options(inheritance='multi') name = Field(Unicode(30), default=u'Untitled Node') path = Field(Unicode(255), default=u'') section = OneToMany('Page', inverse='section') after = OneToOne('Nav', inverse='before') before = OneToMany('Nav', inverse='after') class Page(Nav): using_options(inheritance='multi') content = Field(UnicodeText, nullable=False) posted = Field(DateTime, default=now()) title = Field(Unicode(255), default=u'Untitled Page') heading = Field(Unicode(255)) tags = ManyToMany('Tag') comments = OneToMany('Comment') section = ManyToOne('Nav', inverse='section') class Section(Nav): using_options(inheritance='multi') Errors received on this: sqlalchemy.exc.OperationalError: (OperationalError) table nav has no column named aftr_id u'INSERT INTO nav (name, path, aftr_id, row_type) VALUES (?, ?, ?, ?)' I've also tried: before = ManyToMany('Nav', inverse='before') on Nav in the hopes this might break the problem, but also not. The original SQLAlchemy code from the tutorial for these declarations is as follows: nav_table = schema.Table('nav', meta.metadata, schema.Column('id', types.Integer(), schema.Sequence('nav_id_seq', optional=True), primary_key=True), schema.Column('name', types.Unicode(255), default=u'Untitled Node'), schema.Column('path', types.Unicode(255), default=u''), schema.Column('section', types.Integer(), schema.ForeignKey('nav.id')), schema.Column('before', types.Integer(), default=None), schema.Column('type', types.String(30), nullable=False) ) page_table = schema.Table('page', meta.metadata, schema.Column('id', types.Integer, schema.ForeignKey('nav.id'), primary_key=True), schema.Column('content', types.Text(), nullable=False), schema.Column('posted', types.DateTime(), default=now), schema.Column('title', types.Unicode(255), default=u'Untitled Page'), schema.Column('heading', types.Unicode(255)), ) section_table = sa.Table('section', meta.metadata, schema.Column('id', types.Integer, schema.ForeignKey('nav.id'), primary_key=True), ) orm.mapper(Nav, nav_table, polymorphic_on=nav_table.c.type, polymorphic_identity='nav') orm.mapper(Section, section_table, inherits=Nav, polymorphic_identity='section') orm.mapper(Page, page_table, inherits=Nav, polymorphic_identity='page', properties={ 'comments':orm.relation(Comment, backref='page', cascade='all'), 'tags':orm.relation(Tag, secondary=pagetag_table) }) Any help is much appreciated.

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  • Mac OS X linker error in Qt; CoreGraphics & CGWindowListCreate

    - by Jake Petroules
    Here is my .mm file #include "windowmanagerutils.h" #ifdef Q_OS_MAC #import </System/Library/Frameworks/ApplicationServices.framework/Frameworks/CoreGraphics.framework/Headers/CGWindow.h> QRect WindowManagerUtils::getWindowRect(WId windowId) { CFArrayRef windows = CGWindowListCreate(kCGWindowListOptionOnScreenOnly, kCGNullWindowID); return QRect(); } QRect WindowManagerUtils::getClientRect(WId windowId) { return QRect(); } QString WindowManagerUtils::getWindowText(WId windowId) { return QString(); } WId WindowManagerUtils::rootWindow() { QApplication::desktop()->winId(); } WId WindowManagerUtils::windowFromPoint(const QPoint &p, WId parent, bool(*filterFunction)(WId)) { return NULL; } void WindowManagerUtils::setTopMostCarbon(const QWidget *const window, bool topMost) { if (!window) { return; } // Find a Cocoa equivalent for this Carbon function // [DllImport("/System/Library/Frameworks/Carbon.framework/Versions/Current/Carbon")] // OSStatus ret = HIViewSetZOrder(this->winId(), kHIViewZOrderAbove, NULL); } #endif The linker is telling me "_CGWindowListCreate" is undefined. What libraries must I link to? Apple's documentation is not very helpful on telling what to include or link to, like MSDN is. Also I couldn't just do #import <CGWindow.h>, I had to specify the absolute path to it... any way around that?

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  • How do I get an overview and a methodology for programming in Python

    - by Peter Nielsen
    I've started to learn Python and programming from scratch. I have not programmed before so it's a new experience. I do seem to grasp most of the concepts, from variables to definitions and modules. I still need to learn a lot more about what the different libraries and modules do and also I lack knowledge on OOP and classes in Python. I see people who just program in Python like that's all they have ever done and I am still just coming to grips with it. Is there a way, some tools, a logical methodology that would give me an overview or a good hold of how to handle programming problems ? For instance, I'm trying to create a parser which we need at the office . I also need to create a spider that would collect links from various websites. Is there a formidable way of studying the various modules to see what is needed ? Or is it just nose to the grind stone and understand what the documentation says ? Sorry for the lengthy question..

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  • Array property in Phing

    - by Jahangir
    I have a phing build file that checks the permission of certain files using the <touch> task. <target description="list of files to check permission" name="files-to-test"> <property name="filesToCheck" value=""/> <php expression="file_get_contents('filesToCheck.txt')" returnProperty="filesToCheck"/> <foreach list="${filesToCheck}" param="file" target="permission-test"/> </target> <target description="Test the permission of files that needs to be written" name="permission-test"> <touch file="${file}"/> </target> It calls an extenal file(filesToCheck.txt) which is just a list of different file locations. This works fine. But it prevents me from reusing the same list in my PHP code when I want to access a particular file based on a certain key from the same external file(filesToCheck.txt). I looked through Phing's documentation but didn't find any array Task. Does anyone know of a work around or is creating a new task the only solution for handling an array property in Phing ?

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  • setcontext and makecontext to call a generic function pointer

    - by Simone Margaritelli
    In another question i had the problem to port the code unsigned long stack[] = { 1, 23, 33, 43 }; /* save all the registers and the stack pointer */ unsigned long esp; asm __volatile__ ( "pusha" ); asm __volatile__ ( "mov %%esp, %0" :"=m" (esp)); for( i = 0; i < sizeof(stack); i++ ){ unsigned long val = stack[i]; asm __volatile__ ( "push %0" :: "m"(val) ); } unsigned long ret = function_pointer(); /* restore registers and stack pointer */ asm __volatile__ ( "mov %0, %%esp" :: "m" (esp) ); asm __volatile__ ( "popa" ); To a 64bit platform and many guys told me i should use the setcontext and makecontext functions set instead due to the calling conversion differences between 32 and 64 bits and portability issues. Well, i really can't find any useful documentation online, or at least not the kind i need to implement this, so, how can i use those functions to push arguments onto the stack, call a generic function pointer, obtain the return value and then restore the registers?

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  • Spring security and authentication provider

    - by Pascal
    I'm trying to implement Spring 3 Security in a project, but I can not get rid of the following error: org.springframework.beans.factory.BeanCreationException: Error creating bean with name '_authenticationManager': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: No authentication providers were found in the application context This seems weird, as I did provide an authentication provider! I've added these lines to web. <filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> And this is my applicationContext-security.xml: <http auto-config="false"> <intercept-url pattern="/**" access="ROLE_USER" /> <http-basic /> </http> <authentication-manager alias="authenticationManager"> <authentication-provider> <user-service> <user name="jimi" password="jimispassword" authorities="ROLE_USER, ROLE_ADMIN"/> <user name="bob" password="bobspassword" authorities="ROLE_USER"/> </user-service> </authentication-provider> </authentication-manager> Google couldn't help me much further, nor could the official documentation.

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  • How do I read binary C++ protobuf data using Python protobuf?

    - by nbolton
    The Python version of Google protobuf gives us only: SerializeAsString() Where as the C++ version gives us both: SerializeToArray(...) SerializeAsString() We're writing to our C++ file in binary format, and we'd like to keep it this way. That said, is there a way of reading the binary data into Python and parsing it as if it were a string? Is this the correct way of doing it? binary = get_binary_data() binary_size = get_binary_size() string = None for i in range(len(binary_size)): string += i message = new MyMessage() message.ParseFromString(string) Update: Here's a new example, and a problem: message_length = 512 file = open('foobars.bin', 'rb') eof = False while not eof: data = file.read(message_length) eof = not data if not eof: foo_bar = FooBar() foo_bar.ParseFromString(data) When we get to the foo_bar.ParseFromString(data) line, I get this error: Exception Type: DecodeError Exception Value: Too many bytes when decoding varint. Update 2: It turns out, that the padding on the binary data was throwing protobuf off; too many bytes were being sent in, as the message suggests (in this case it was referring to the padding). This padding comes from using the C++ protobuf function, SerializeToArray on a fixed-length buffer. To eliminate this, I have used this temproary code: message_length = 512 file = open('foobars.bin', 'rb') eof = False while not eof: data = file.read(message_length) eof = not data string = '' for i in range(0, len(data)): byte = data[i] if byte != '\xcc': # yuck! string += data[i] if not eof: foo_bar = FooBar() foo_bar.ParseFromString(string) There is a design flaw here I think. I will re-implement my C++ code so that it writes variable length arrays to the binary file. As advised by the protobuf documentation, I will prefix each message with it's binary size so that I know how much to read when I'm opening the file with Python.

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