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  • Safe to update separate regions of a BufferedImage in separate threads?

    - by finnw
    I have a collection of BufferedImage instances, one main image and some subimages created by calling getSubImage on the main image. The subimages do not overlap. I am also making modifications to the subimage and I want to split this into multiple threads, one per subimage. From my understanding of how BufferedImage, Raster and DataBuffer work, this should be safe because: Each instance of BufferedImage (and its respective WritableRaster) is accessed from only one thread. The shared ColorModel is immutable The DataBuffer has no fields that can be modified (the only thing that can change is elements of the backing array.) Modifying disjoint segments of an array in separate threads is safe. However I cannot find anything in the documentation that says that it is definitely safe to do this. Can I assume it is safe? I know that it is possible to work on copies of the child Rasters but I would prefer to avoid this because of memory constraints. Otherwise, is it possible to make the operation thread-safe without copying regions of the parent image?

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  • iPhone app crashes on start-up, in stack-trace only messages from built-in frameworks

    - by Aleksejs
    My app some times crashes at start-up. In stack-trace only messages from built-in frameworks. An excerpt from a crash log: OS Version: iPhone OS 3.1.3 (7E18) Report Version: 104 Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Codes: KERN_PROTECTION_FAILURE at 0x000e6000 Crashed Thread: 0 Thread 0 Crashed: 0 CoreGraphics 0x339305d8 argb32_image_mark_RGB32 + 704 1 CoreGraphics 0x338dbcd4 argb32_image + 1640 2 libRIP.A.dylib 0x320d99f0 ripl_Mark 3 libRIP.A.dylib 0x320db3ac ripl_BltImage 4 libRIP.A.dylib 0x320cc2a0 ripc_RenderImage 5 libRIP.A.dylib 0x320d5238 ripc_DrawImage 6 CoreGraphics 0x338d7da4 CGContextDelegateDrawImage + 80 7 CoreGraphics 0x338d7d14 CGContextDrawImage + 364 8 UIKit 0x324ee68c compositeCGImageRefInRect 9 UIKit 0x324ee564 -[UIImage(UIImageDeprecated) compositeToRect:fromRect:operation:fraction:] 10 UIKit 0x32556f44 -[UINavigationBar drawBackButtonBackgroundInRect:withStyle:pressed:] 11 UIKit 0x32556b00 -[UINavigationItemButtonView drawRect:] 12 UIKit 0x324ecbc4 -[UIView(CALayerDelegate) drawLayer:inContext:] 13 QuartzCore 0x311cacfc -[CALayer drawInContext:] 14 QuartzCore 0x311cab00 backing_callback 15 QuartzCore 0x311ca388 CABackingStoreUpdate 16 QuartzCore 0x311c978c -[CALayer _display] 17 QuartzCore 0x311c941c -[CALayer display] 18 QuartzCore 0x311c9368 CALayerDisplayIfNeeded 19 QuartzCore 0x311c8848 CA::Context::commit_transaction(CA::Transaction*) 20 QuartzCore 0x311c846c CA::Transaction::commit() 21 QuartzCore 0x311c8318 +[CATransaction flush] 22 UIKit 0x324f5e94 -[UIApplication _reportAppLaunchFinished] 23 UIKit 0x324a7a80 -[UIApplication _runWithURL:sourceBundleID:] 24 UIKit 0x324f8df8 -[UIApplication handleEvent:withNewEvent:] 25 UIKit 0x324f8634 -[UIApplication sendEvent:] 26 UIKit 0x324f808c _UIApplicationHandleEvent 27 GraphicsServices 0x335067dc PurpleEventCallback 28 CoreFoundation 0x323f5524 CFRunLoopRunSpecific 29 CoreFoundation 0x323f4c18 CFRunLoopRunInMode 30 UIKit 0x324a6c00 -[UIApplication _run] 31 UIKit 0x324a5228 UIApplicationMain 32 Journaler 0x000029ac main (main.m:14) 33 Journaler 0x00002948 start + 44 File main.m is simple as possible: #import <UIKit/UIKit.h> int main(int argc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; int retVal = UIApplicationMain(argc, argv, nil, nil); // line 14 [pool release]; return retVal; } What my cause the app to crash?

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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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  • Regex to extract portions of file name

    - by jakesankey
    I have text files formatted as such: R156484COMP_004A7001_20100104_065119.txt I need to consistently extract the R****COMP, the 004A7001 number, 20100104 (date), and don't care about the 065119 number. the problem is that not ALL of the files being parsed have the exact naming convention. some may be like this: R168166CRIT_156B2075_SU2_20091223_123456.txt or R285476COMP_SU1_125A6025_20100407_123456.txt So how could I use regex instead of split to ensure I am always getting that serial (ex. 004A7001), the date (ex. 20100104), and the R****COMP (or CRIT)??? Here is what I do now but it only gets the files formatted like my first example. if (file.Count(c => c == '_') != 3) continue; and further down in the code I have: string RNumber = Path.GetFileNameWithoutExtension(file); string RNumberE = RNumber.Split('_')[0]; string RNumberD = RNumber.Split('_')[1]; string RNumberDate = RNumber.Split('_')[2]; DateTime dateTime = DateTime.ParseExact(RNumberDate, "yyyyMMdd", Thread.CurrentThread.CurrentCulture); string cmmDate = dateTime.ToString("dd-MMM-yyyy"); UPDATE: This is now where I am at -- I get an error to parse RNumberDate to an actual date format. "Cannot implicitly convert type 'RegularExpressions.Match' to 'string' string RNumber = Path.GetFileNameWithoutExtension(file); Match RNumberE = Regex.Match(RNumber, @"^(R|L)\d{6}(COMP|CRIT|TEST|SU[1-9])(?=_)", RegexOptions.IgnoreCase); Match RNumberD = Regex.Match(RNumber, @"(?<=_)\d{3}[A-Z]\d{4}(?=_)", RegexOptions.IgnoreCase); Match RNumberDate = Regex.Match(RNumber, @"(?<=_)\d{8}(?=_)", RegexOptions.IgnoreCase); DateTime dateTime = DateTime.ParseExact(RNumberDate, "yyyyMMdd", Thread.CurrentThread.CurrentCulture); string cmmDate = dateTime.ToString("dd-MMM-yyyy")

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  • Using NHibernate's HQL to make a query with multiple inner joins

    - by Abu Dhabi
    The problem here consists of translating a statement written in LINQ to SQL syntax into the equivalent for NHibernate. The LINQ to SQL code looks like so: var whatevervar = from threads in context.THREADs join threadposts in context.THREADPOSTs on threads.thread_id equals threadposts.thread_id join posts1 in context.POSTs on threadposts.post_id equals posts1.post_id join users in context.USERs on posts1.user_id equals users.user_id orderby posts1.post_time where threads.thread_id == int.Parse(id) select new { threads.thread_topic, posts1.post_time, users.user_display_name, users.user_signature, users.user_avatar, posts1.post_body, posts1.post_topic }; It's essentially trying to grab a list of posts within a given forum thread. The best I've been able to come up with (with the help of the helpful users of this site) for NHibernate is: var whatevervar = session.CreateQuery("select t.Thread_topic, p.Post_time, " + "u.User_display_name, u.User_signature, " + "u.User_avatar, p.Post_body, p.Post_topic " + "from THREADPOST tp " + "inner join tp.Thread_ as t " + "inner join tp.Post_ as p " + "inner join p.User_ as u " + "where tp.Thread_ = :what") .SetParameter<THREAD>("what", threadid) .SetResultTransformer(Transformers.AliasToBean(typeof(MyDTO))) .List<MyDTO>(); But that doesn't parse well, complaining that the aliases for the joined tables are null references. MyDTO is a custom type for the output: public class MyDTO { public string thread_topic { get; set; } public DateTime post_time { get; set; } public string user_display_name { get; set; } public string user_signature { get; set; } public string user_avatar { get; set; } public string post_topic { get; set; } public string post_body { get; set; } } I'm out of ideas, and while doing this by direct SQL query is possible, I'd like to do it properly, without defeating the purpose of using an ORM. Thanks in advance!

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  • Debugging strategy to find the cause of bad_alloc

    - by SalamiArmi
    I have a fairly serious bug in my program - occasional calls to new() throw a bad_alloc. From the documentation I can find on bad_alloc, it seems to be thrown for these reasons: When the computer runs out of memory (which definitely isn't happening, I have 4GB of RAM, program throws bad_alloc when using less than 5MB (checked in taskmanager) with nothing serious running in the background). If the memory becomes too fragmented to allocate new blocks (which, again, is unlikely - the largest sized block I ever allocate would be about 1KB, and that doesn't get done more than 100 times before the crash occurs). Based on these descriptions, I don't really have anywhere in which a bad_alloc could be thrown. However, the application I am running runs more than one thread, which could possibly be contributing to the problem. By testing all of the objects on a single thread, everything seems to be working smoothly. The only other thing that I can think of that is going on here could be some kind of race-condition caused by calling new() in more than one place at the same time, but I've tried adding mutexes to prevent that behaviour to no effect. Because the program is several hundred lines and I have no idea where the problem actually lies, I'm not sure of what, if any, code snippets to post. Instead, I was wondering if there were any tools that will help me test for this kind of thing, or if there are any general strategies that can help me with this problem. I'm using Microsoft Visual Studio 2008, with Poco for threading.

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  • delayed evaluation of code in subroutines - 5.8 vs. 5.10 and 5.12

    - by Brock
    This bit of code behaves differently under perl 5.8 than it does under perl 5.12: my $badcode = sub { 1 / 0 }; print "Made it past the bad code.\n"; [brock@chase tmp]$ /usr/bin/perl -v This is perl, v5.8.8 built for i486-linux-gnu-thread-multi [brock@chase tmp]$ /usr/bin/perl badcode.pl Illegal division by zero at badcode.pl line 1. [brock@chase tmp]$ /usr/local/bin/perl -v This is perl 5, version 12, subversion 0 (v5.12.0) built for i686-linux [brock@chase tmp]$ /usr/local/bin/perl badcode.pl Made it past the bad code. Under perl 5.10.1, it behaves as it does under 5.12: brock@laptop:/var/tmp$ perl -v This is perl, v5.10.1 (*) built for i486-linux-gnu-thread-multi brock@laptop:/var/tmp$ perl badcode.pl Made it past the bad code. I get the same results with a named subroutine, e.g. sub badcode { 1 / 0 } I don't see anything about this in the perl5100delta pod. Is this an undocumented change? A unintended side effect of some other change? (For the record, I think 5.10 and 5.12 are doing the Right Thing.)

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  • Reason for Null pointer Exception

    - by Rahul Varma
    Hi, I cant figure out why my program is showing null pointer exception. Plz help me...Here's the program... public class MusicListActivity extends Activity { List<HashMap<String, String>> songNodeDet = new ArrayList<HashMap<String,String>>(); HashMap<?,?>[] songNodeWeb; XMLRPCClient client; String logInSess; ArrayList<String> paths=new ArrayList<String>(); public ListAdapter adapter ; Object[] websongListObject; List<SongsList> SngList=new ArrayList<SongsList>(); Runnable r; ProgressDialog p; ListView lv; String s; @Override public void onCreate(Bundle si){ super.onCreate(si); setContentView(R.layout.openadiuofile); lv=(ListView)findViewById(R.id.list1); r=new Runnable(){ public void run(){ try{ getSongs(); } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (XMLRPCException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }; Thread t=new Thread(r,"background"); t.start(); Log.e("***","process over"); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); } private Runnable returnRes = new Runnable() { @Override public void run() { Log.d("handler","handler"); removeDialog(0); p.dismiss(); list(); } }; public void list() { Log.d("#####","#####"); LayoutInflater inflater=getLayoutInflater(); String[] from={}; int[] n={}; adapter=new SongsAdapter(getApplicationContext(),songNodeDet,R.layout.row,from,n,inflater); lv.setAdapter(adapter);} private Handler handler = new Handler() { public void handleMessage(Message msg){ Log.d("*****","handler"); removeDialog(0); p.dismiss(); } }; public void webObjectList(Object[] imgListObj,String logInSess) throws XMLRPCException{ songNodeWeb = new HashMap<?,?>[imgListObj.length]; if(imgListObj!=null){ Log.e("completed","completed"); for(int i=0;i<imgListObj.length;i++){ //imgListObj.length songNodeWeb[i]=(HashMap<?,?>)imgListObj[i]; String nodeid=(String) songNodeWeb[i].get("nid"); break; Log.e("img",i+"completed"); HashMap<String,String> nData=new HashMap<String,String>(); nData.put("nid",nodeid); Object nodeget=client.call("node.get",logInSess,nodeid); HashMap<?,?> imgNode=(HashMap<?,?>)nodeget; String titleName=(String) imgNode.get("titles"); String movieName=(String) imgNode.get("album"); String singerName=(String) imgNode.get("artist"); nData.put("titles", titleName); nData.put("album", movieName); nData.put("artist", singerName); Object[] imgObject=(Object[])imgNode.get("field_image"); HashMap<?,?>[] imgDetails=new HashMap<?,?>[imgObject.length]; imgDetails[0]=(HashMap<?, ?>)imgObject[0]; String path=(String) imgDetails[0].get("filepath"); if(path.contains(" ")){ path=path.replace(" ", "%20"); } String imgPath="http://www.gorinka.com/"+path; paths.add(imgPath); nData.put("path", imgPath); Log.e("my path",path); String mime=(String)imgDetails[0].get("filemime"); nData.put("mime", mime); SongsList songs=new SongsList(titleName,movieName,singerName,imgPath,imgPath); SngList.add(i,songs); songNodeDet.add(i,nData); } Log.e("paths values",paths.toString()); // return imgNodeDet; handler.sendEmptyMessage(0); } } public void getSongs() throws MalformedURLException, XMLRPCException { String ur="http://www.gorinka.com/?q=services/xmlrpc"; URL u=new URL(ur); client = new XMLRPCClient(u); //Connecting to the website HashMap<?, ?> siteConn =(HashMap<?, ?>) client.call("system.connect"); // Getting initial sessio id String initSess=(String)siteConn.get("sessid"); //Login to the site using session id HashMap<?, ?> logInConn =(HashMap<?, ?>) client.call("user.login",initSess,"prakash","stellentsoft2009"); //Getting Login sessid logInSess=(String)logInConn.get("sessid"); websongListObject =(Object[]) client.call("nodetype.get",logInSess,""); webObjectList(websongListObject,logInSess); Log.d("webObjectList","webObjectList"); runOnUiThread(returnRes); } } Here's the Adapter associated... public class SongsAdapter extends SimpleAdapter{ static List<HashMap<String,String>> songsList; Context context; LayoutInflater inflater; public SongsAdapter(Context context,List<HashMap<String,String>> imgListWeb,int layout,String[] from,int[] to,LayoutInflater inflater) { super(context,songsList,layout,from,to); this.songsList=songsList; this.context=context; this.inflater=inflater; // TODO Auto-generated constructor stub } @Override public View getView(int postition,View convertView,ViewGroup parent)throws java.lang.OutOfMemoryError{ try { View v = ((LayoutInflater) inflater).inflate(R.layout.row,null); ImageView images=(ImageView)v.findViewById(R.id.image); TextView tvTitle=(TextView)v.findViewById(R.id.text1); TextView tvAlbum=(TextView)v.findViewById(R.id.text2); TextView tvArtist=(TextView)v.findViewById(R.id.text3); HashMap<String,String> songsHash=songsList.get(postition); String path=songsHash.get("path"); String title=songsHash.get("title"); String album=songsHash.get("album"); String artist=songsHash.get("artist"); String imgPath=path; final ImageView imageView = (ImageView) v.findViewById(R.id.image); AsyncImageLoaderv asyncImageLoader=new AsyncImageLoaderv(); Bitmap cachedImage = asyncImageLoader.loadDrawable(imgPath, new AsyncImageLoaderv.ImageCallback() { public void imageLoaded(Bitmap imageDrawable, String imageUrl) { imageView.setImageBitmap(imageDrawable); } }); imageView.setImageBitmap(cachedImage); tvTitle.setText(title); tvAlbum.setText(album); tvArtist.setText(artist); return v; } catch(Exception e){ Log.e("error",e.toString()); } return null; } public static Bitmap loadImageFromUrl(String url) { InputStream inputStream;Bitmap b; try { inputStream = (InputStream) new URL(url).getContent(); BitmapFactory.Options bpo= new BitmapFactory.Options(); bpo.inSampleSize=2; b=BitmapFactory.decodeStream(inputStream, null,bpo ); return b; } catch (IOException e) { throw new RuntimeException(e); } } } Here is what logcat is showing... 04-23 16:02:02.211: ERROR/completed(1450): completed 04-23 16:02:02.211: ERROR/paths values(1450): [] 04-23 16:02:02.211: DEBUG/*****(1450): handler 04-23 16:02:02.211: DEBUG/AndroidRuntime(1450): Shutting down VM 04-23 16:02:02.211: WARN/dalvikvm(1450): threadid=3: thread exiting with uncaught exception (group=0x4001aa28) 04-23 16:02:02.222: ERROR/AndroidRuntime(1450): Uncaught handler: thread main exiting due to uncaught exception 04-23 16:02:02.241: DEBUG/webObjectList(1450): webObjectList 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): java.lang.NullPointerException 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at com.stellent.gorinka.MusicListActivity$2.handleMessage(MusicListActivity.java:81) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at android.os.Handler.dispatchMessage(Handler.java:99) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at android.os.Looper.loop(Looper.java:123) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at android.app.ActivityThread.main(ActivityThread.java:4203) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at java.lang.reflect.Method.invokeNative(Native Method) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at java.lang.reflect.Method.invoke(Method.java:521) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 04-23 16:02:02.252: ERROR/AndroidRuntime(1450): at dalvik.system.NativeStart.main(Native Method) I have declared the getter and setter methods in a seperate claa named SongsList. Plz help me determine the problem...

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  • How to configure a system-wide package in osgi?

    - by cheng81
    I need to made available a library to some bundles. This library makes use of RMI, so it needs (as far as I know, at least) to use the system class loader in order to work (I tried to "osgi-fy" the library, which results in classcastexceptions at runtime). So what I did was to remove the dependencies from the bundles that use that library, compile them with the library included in the property jars.extra.classpath (in the build.properties of the eclipse project). Then I added org.osgi.framework.bootdelegation=com.blipsystems.* in the felix configuration file and started the felix container with the followin command line: java -classpath lib/blipnetapi.jar -jar bin/felix.jar ..which in turns throwed a NoClassDefFoundException for a class of the blipnetapi.jar library: ERROR: Error starting file:/home/frza/felix/load/BlipnetApiOsgiService_1.0.0.1.jar (org.osgi.framework.BundleException: Activator start error in bundle BlipnetApiOsgiService [30].) java.lang.NoClassDefFoundError: com/blipsystems/blipnet/api/util/BlipNetSecurityManager at java.lang.Class.getDeclaredConstructors0(Native Method) at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389) at java.lang.Class.getConstructor0(Class.java:2699) at java.lang.Class.newInstance0(Class.java:326) at java.lang.Class.newInstance(Class.java:308) at org.apache.felix.framework.Felix.createBundleActivator(Felix.java:3525) at org.apache.felix.framework.Felix.activateBundle(Felix.java:1694) at org.apache.felix.framework.Felix.startBundle(Felix.java:1621) at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1076) at org.apache.felix.framework.StartLevelImpl.run(StartLevelImpl.java:264) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.ClassNotFoundException: com.blipsystems.blipnet.api.util.BlipNetSecurityManager at org.apache.felix.framework.ModuleImpl.findClassOrResourceByDelegation(ModuleImpl.java:726) at org.apache.felix.framework.ModuleImpl.access$100(ModuleImpl.java:60) at org.apache.felix.framework.ModuleImpl$ModuleClassLoader.loadClass(ModuleImpl.java:1631) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319) ... 11 more So my question is: am I missing something? I did something wrong?

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  • What can cause Windows to unhook a low level (global) keyboard hook?

    - by Davy8
    We have some global keyboard hooks installed via SetWindowsHookEx with WH_KEYBOARD_LL that appear to randomly get unhooked by Windows. We verified that they hook was no longer attached because calling UnhookWindowsHookEx on the handle returns false. (Also verified that it returns true when it was working properly) There doesn't seem to be a consistent repro, I've heard that they can get unhooked due to timeouts or exceptions getting thrown, but I've tried both just letting it sit on a breakpoint in the handling method for over a minute, as well as just throwing a random exception (C#) and it still appears to work. In our callback we quickly post to another thread, so that probably isn't the issue. I've read about solutions in Windows 7 for setting the timeout higher in the registry because Windows 7 is more aggressive about the timeouts apparently (we're all running Win7 here, so not sure if this occurs on other OS's) , but that doesn't seem like an ideal solution. I've considered just having a background thread running to refresh the hook every once in a while, which is hackish, but I don't know of any real negative consequences of doing that, and it seems better than changing a global Windows registry setting. Any other suggestions or solutions? The delegates are not being GC'd since they're static members, which is one cause that I've read about.

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  • Accessing class member variables inside a BackgroundWorker's DoWork event handler, and other Backgro

    - by Justin
    Question 1 In the DoWork event handler of a BackgroundWorker, is it safe to access (for both reading and writing) member variables of the class that contains the BackgroundWorker? Is it safe to access other variables that are not declared inside the DoWork event handler itself? Obviously DoWork should not be accessing any UI objects of, say, a WinForms application, as the UI should only be updated from the UI thread. But what about accessing other (not UI-related) member variables? The reason why I ask is that I've seen the occasional comment come up while Googling saying that accessing member variables is not allowed. The only example I can find at the moment is a comment on this MSDN page, which says: Note, that the BGW can cause exceptions if it attempts to access or modify class level variables. All data must be passed to it by delegates and events. And also: NEVER. NEVER. Never try to reference variables not declared inside of DoWork. It may seem to work at times, but in reality you are just getting lucky. As far as I know, MSDN itself does not document any restrictions of this kind (although if I'm wrong, I'd appreciate a link). But comments like these do seem to pop up every now and again. (Of course if DoWork does access/modify a member variable that could be accessed/modified by the main thread at the same time, it is necessary to synchronise access to that field, eg by using a locking object. But the above quotes seem to require a blanket ban of accessing member variables, rather than just synchronising access!) Question 2 To make this into a more general question, are there any other (not documented?) restrictions that users of the BackgroundWorker should be aware of, aside from the above? Any "best practices", perhaps?

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  • How upload files to azure in background with Delphi and OmniThread?

    - by mamcx
    I have tried to upload +100 files to azure with Delphi. However, the calls block the main thread, so I want to do this with a async call or with a background thread. This is what I do now (like explained here): procedure TCloudManager.UploadTask(const input: TOmniValue; var output: TOmniValue); var FileTask:TFileTask; begin FileTask := input.AsRecord<TFileTask>; Upload(FileTask.BaseFolder, FileTask.LocalFile, FileTask.CloudFile); end; function TCloudManager.MassiveUpload(const BaseFolder: String; Files: TDictionary<String, String>): TStringList; var pipeline: IOmniPipeline; FileInfo : TPair<String,String>; FileTask:TFileTask; begin // set up pipeline pipeline := Parallel.Pipeline .Stage(UploadTask) .NumTasks(Environment.Process.Affinity.Count * 2) .Run; // insert URLs to be retrieved for FileInfo in Files do begin FileTask.LocalFile := FileInfo.Key; FileTask.CloudFile := FileInfo.Value; FileTask.BaseFolder := BaseFolder; pipeline.Input.Add(TOmniValue.FromRecord(FileTask)); end;//for pipeline.Input.CompleteAdding; // wait for pipeline to complete pipeline.WaitFor(INFINITE); end; However this block too (why? I don't understand).

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  • CFHost DNS Resolution - When is it OK to use synchronous API?

    - by Jasarien
    I went to the iPhone Developer Tech Talk a few months ago and asked one of the gurus there about the lack of NSHost on the iPhone. Some code I was porting to the iPhone made significant use of NSHost throughout its networking code. I was told that NSHost is on the iPhone, but its private. I was also told that NSHost is a synchronous API and that I shouldn't use it anyway. (If anyone could elaborate on why it shouldn't be used, as a bonus, that'd be great.) I can see the caveats of using synchronous API's on the main thread in that they'll block until complete - and that's never a good thing with network code because there are so many factors that could cause the API to block the thread for a significant amount of time. My solution was to write a wrapper around CFHost's asynchronous resolution functions. The result works quite well, and I'm considering releasing it into the public domain. But my question is this: Say my app only resolves a hostname once per run, during the connecting phase, and then cache's it for the rest of the session. During the time it is resolving, a modal screen is shown telling the user "Connecting" with a nice spinner. Does it really matter whether or not the resolution is asynchronous?? The user has to wait to connect anyway, and the resolution is only done on the first connection. Subsequent connections use the cached result of the resolution. When is it OK to be synchronous and when should things be asynchronous?

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  • Android java.lang.VerifyError for private method with annotated argument.

    - by alex2k8
    I have a very simple project that compiles, but can't be started on Emulator. The problem is with this method: private void bar(@Some String a) {} // java.lang.VerifyError The issue can be avoided if annotation removed private void bar(String a) {} // OK or the method visibility changed: void bar(@Some String a) {} // OK public void bar(@Some String a) {} // OK protected void bar(@Some String a) {} // OK Any idea what is wrong with original method? Is this a dalvik bug, or? If some one whould like to experiment with code, here it is: Test.java: public class Test { private void bar(@Some String a) {} public void foo() { bar(null); } } Some.java: public @interface Some {} MainActivity.java: public class MainActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); new Test().foo(); } } Stack trace: ERROR/dalvikvm(1358): Could not find method com.my.Test.bar, referenced from method com.my.Test.foo WARN/dalvikvm(1358): VFY: unable to resolve direct method 11: Lcom/my/Test;.bar (Ljava/lang/String;)V WARN/dalvikvm(1358): VFY: rejecting opcode 0x70 at 0x0001 WARN/dalvikvm(1358): VFY: rejected Lcom/my/Test;.foo ()V WARN/dalvikvm(1358): Verifier rejected class Lcom/my/Test; DEBUG/AndroidRuntime(1358): Shutting down VM WARN/dalvikvm(1358): threadid=3: thread exiting with uncaught exception (group=0x4000fe70) ERROR/AndroidRuntime(1358): Uncaught handler: thread main exiting due to uncaught exception ERROR/AndroidRuntime(1358): java.lang.VerifyError: com.my.Test ERROR/AndroidRuntime(1358): at com.my.MainActivity.onCreate(MainActivity.java:13) ERROR/AndroidRuntime(1358): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123) ERROR/AndroidRuntime(1358): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2231) ERROR/AndroidRuntime(1358): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2284) ERROR/AndroidRuntime(1358): at android.app.ActivityThread.access$1800(ActivityThread.java:112) ERROR/AndroidRuntime(1358): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1692) ERROR/AndroidRuntime(1358): at android.os.Handler.dispatchMessage(Handler.java:99) ERROR/AndroidRuntime(1358): at android.os.Looper.loop(Looper.java:123) ERROR/AndroidRuntime(1358): at android.app.ActivityThread.main(ActivityThread.java:3948) ERROR/AndroidRuntime(1358): at java.lang.reflect.Method.invokeNative(Native Method) ERROR/AndroidRuntime(1358): at java.lang.reflect.Method.invoke(Method.java:521) ERROR/AndroidRuntime(1358): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782) ERROR/AndroidRuntime(1358): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540) ERROR/AndroidRuntime(1358): at dalvik.system.NativeStart.main(Native Method)

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  • CruiseControlException "log.xml does not exist" help

    - by Castanho
    Hi all.... I have a project that have cruiseControl running to build our things. In my config.main I have a <onsuccess> with a <antpublisher> But when some error occur in the ANT I'm receiving a exception: exception publishing results with net.sourceforge.cruisecontrol.publishers.OnSuccessPublisher for project usforce net.sourceforge.cruisecontrol.CruiseControlException: ant logfile /home/usforce/cruisecontrol-bin-2.7.3/log.xml does not exist. at net.sourceforge.cruisecontrol.builders.AntBuilder.getAntLogAsElement(AntBuilder.java:424) at net.sourceforge.cruisecontrol.builders.AntBuilder.build(AntBuilder.java:213) at net.sourceforge.cruisecontrol.publishers.AntPublisher.publish(AntPublisher.java:86) at net.sourceforge.cruisecontrol.publishers.ConditionalPublisher.publish(ConditionalPublisher.java:61) at net.sourceforge.cruisecontrol.Project.publish(Project.java:750) at net.sourceforge.cruisecontrol.Project.build(Project.java:264) at net.sourceforge.cruisecontrol.Project.execute(Project.java:149) at net.sourceforge.cruisecontrol.ProjectConfig.execute(ProjectConfig.java:405) at net.sourceforge.cruisecontrol.ProjectWrapper.run(ProjectWrapper.java:69) at java.lang.Thread.run(Thread.java:595) I really dont have this log.xml... And I don'k know how this file should be, a log4j? Commons? I google it and could not found what this file for.. Well any tips could help! Thanks in advance

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  • Using a custom IList obtained through NHibernate

    - by Abu Dhabi
    Hi.I'm trying to write a web page in .NET, using C# and NHibernate 2.1. The pertinent code looks like this: var whatevervar = session.CreateSQLQuery("select thread_topic, post_time, user_display_name, user_signature, user_avatar, post_topic, post_body from THREAD, [USER], POST, THREADPOST where THREADPOST.thread_id=" + id + " and THREADPOST.thread_id=THREAD.thread_id and [USER].user_id=POST.user_id and POST.post_id=THREADPOST.post_id ORDER BY post_time;").List(); (I have tried to use joins in HQL, but then fell back on this query, due to HQL's unreadability.) The problem is that I'm getting a result that is incompatible with a repeater. When I try this: posts.DataSource = whatevervar.; posts.DataBind(); ...I get this: DataBinding: 'System.Object[]' does not contain a property with the name 'user_avatar'. In an earlier project, I used LINQ to SQL for this same purpose, and it looked like so: var whatevervar = from threads in context.THREADs join threadposts in context.THREADPOSTs on threads.thread_id equals threadposts.thread_id join posts1 in context.POSTs on threadposts.post_id equals posts1.post_id join users in context.USERs on posts1.user_id equals users.user_id orderby posts1.post_time where threads.thread_id == int.Parse(id) select new { threads.thread_topic, posts1.post_time, users.user_display_name, users.user_signature, users.user_avatar, posts1.post_body, posts1.post_topic }; That worked, and now I want to do the same with NHibernate. Unfortunately, I don't know how to make the repeater recognize the fields of the result of the query. Thanks in advance!

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  • cakephp secure link using html helper link method..

    - by Aaron
    What's the best way in cakephp to extend the html-link function so that I can tell it to output a secure(https) link? Right now, I've added my own secure_link function to app_helpers that's basically a copy of the link function but adding a https to the beginning. But it seems like there should be a better way of overriding the html-link method so that I can specify a secure option. http://groups.google.com/group/cake-php/browse%5Fthread/thread/e801b31cd3db809a I also started a thread on the google groups and someone suggested doing something like $html->link('my account', array('base' => 'https://', 'controller' => 'users')); but I couldn't get that working. Just to add, this is what is outputted when I have the above code. <a href="/users/index/base:https:/">my account</a> I think there's a bug in the cake/libs/router.php on line 850. There's a keyword 'bare' and I think it should be 'base' Though changing it to base doesn't seem to fix it. From what I gather, it's telling it to exclude those keys that are passed in so that they don't get included as parameters. But I'm puzzled as to why it's a 'bare' keyword and the only reason I can come up with is that it's a type.

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  • Are lambda expressions/delegates in C# "pure", or can they be?

    - by Bob
    I recently asked about functional programs having no side effects, and learned what this means for making parallelized tasks trivial. Specifically, that "pure" functions make this trivial as they have no side effects. I've also recently been looking into LINQ and lambda expressions as I've run across examples many times here on StackOverflow involving enumeration. That got me to wondering if parallelizing an enumeration or loop can be "easier" in C# now. Are lambda expressions "pure" enough to pull off trivial parallelizing? Maybe it depends on what you're doing with the expression, but can they be pure enough? Would something like this be theoretically possible/trivial in C#?: Break the loop into chunks Run a thread to loop through each chunk Run a function that does something with the value from the current loop position of each thread For instance, say I had a bunch of objects in a game loop (as I am developing a game and was thinking about the possibility of multiple threads) and had to do something with each of them every frame, would the above be trivial to pull off? Looking at IEnumerable it seems it only keeps track of the current position, so I'm not sure I could use the normal generic collections to break the enumeration into "chunks". Sorry about this question. I used bullets above instead of pseudo-code because I don't even know enough to write pseudo-code off the top of my head. My .NET knowledge has been purely simple business stuff and I'm new to delegates and threads, etc. I mainly want to know if the above approach is good for pursuing, and if delegates/lambdas don't have to be worried about when it comes to their parallelization.

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  • Are there some cases where Python threads can safely manipulate shared state?

    - by erikg
    Some discussion in another question has encouraged me to to better understand cases where locking is required in multithreaded Python programs. Per this article on threading in Python, I have several solid, testable examples of pitfalls that can occur when multiple threads access shared state. The example race condition provided on this page involves races between threads reading and manipulating a shared variable stored in a dictionary. I think the case for a race here is very obvious, and fortunately is eminently testable. However, I have been unable to evoke a race condition with atomic operations such as list appends or variable increments. This test exhaustively attempts to demonstrate such a race: from threading import Thread, Lock import operator def contains_all_ints(l, n): l.sort() for i in xrange(0, n): if l[i] != i: return False return True def test(ntests): results = [] threads = [] def lockless_append(i): results.append(i) for i in xrange(0, ntests): threads.append(Thread(target=lockless_append, args=(i,))) threads[i].start() for i in xrange(0, ntests): threads[i].join() if len(results) != ntests or not contains_all_ints(results, ntests): return False else: return True for i in range(0,100): if test(100000): print "OK", i else: print "appending to a list without locks *is* unsafe" exit() I have run the test above without failure (100x 100k multithreaded appends). Can anyone get it to fail? Is there another class of object which can be made to misbehave via atomic, incremental, modification by threads? Do these implicitly 'atomic' semantics apply to other operations in Python? Is this directly related to the GIL?

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  • Python Locking Implementation (with threading module)

    - by Matty
    This is probably a rudimentary question, but I'm new to threaded programming in Python and am not entirely sure what the correct practice is. Should I be creating a single lock object (either globally or being passed around) and using that everywhere that I need to do locking? Or, should I be creating multiple lock instances in each of the classes where I will be employing them. Take these 2 rudimentary code samples, which direction is best to go? The main difference being that a single lock instance is used in both class A and B in the second, while multiple instances are used in the first. Sample 1 class A(): def __init__(self, theList): self.theList = theList self.lock = threading.Lock() def poll(self): while True: # do some stuff that eventually needs to work with theList self.lock.acquire() try: self.theList.append(something) finally: self.lock.release() class B(threading.Thread): def __init__(self,theList): self.theList = theList self.lock = threading.Lock() self.start() def run(self): while True: # do some stuff that eventually needs to work with theList self.lock.acquire() try: self.theList.remove(something) finally: self.lock.release() if __name__ == "__main__": aList = [] for x in range(10): B(aList) A(aList).poll() Sample 2 class A(): def __init__(self, theList,lock): self.theList = theList self.lock = lock def poll(self): while True: # do some stuff that eventually needs to work with theList self.lock.acquire() try: self.theList.append(something) finally: self.lock.release() class B(threading.Thread): def __init__(self,theList,lock): self.theList = theList self.lock = lock self.start() def run(self): while True: # do some stuff that eventually needs to work with theList self.lock.acquire() try: self.theList.remove(something) finally: self.lock.release() if __name__ == "__main__": lock = threading.Lock() aList = [] for x in range(10): B(aList,lock) A(aList,lock).poll()

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  • PHP get "Application Root" in Xampp on Windows correctly

    - by Michael Mao
    Hi all: I found this thread on StackOverflow about how to get the "Application Root" from inside my web app. However, most of the approaches suggested in that thread can hardly be applied to my Xampp on Windows. Say, I've got a "common.php" which stays inside my web app's app directory: / /app/common.php /protected/index.php In my common.php, what I've got is like this: define('DOCROOT', $_SERVER['DOCUMENT_ROOT']); define('ABSPATH', dirname(__FILE__)); define('COMMONSCRIPT', $_SERVER['PHP_SELF']); After I required the common.php inside the /protected/index.php, I found this: C:/xampp/htdocs //<== echo DOCROOT; C:\xampp\htdocs\comic\app //<== echo ABSPATH /comic/protected/index.php //<== echo COMMONSCRIPT So the most troublesome part is the path delimiters are not universal, plus, it seems all superglobals from the $_SERVER[] asso array, such as $_SERVER['PHP_SELF'], are relative to the "caller" script, not the "callee" script. It seems that I can only rely on dirname(__FILE__) to make sure this always returns an absolute path to the common.php file. I can certainly parse the returning values from DOCROOT and ABSPATH and then calculate the correct "application root". For instance, I can compare the parts after htdocs and substitute all backslashes with slashes to get a unix-like path I wonder is this the right way to handle this? What if I deploy my web app on a LAMP environment? would this environment-dependent approach bomb me out? I have used some PHP frameworks such as CakePHP and CodeIgniter, to be frank, They just work on either LAMP or WAMP, but I am not sure how they approached such a elegant solution. Many thanks in advance for all the hints and suggestions.

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  • Asynchronous crawling F#

    - by jlezard
    When crawling on webpages I need to be careful as to not make too many requests to the same domain, for example I want to put 1 s between requests. From what I understand it is the time between requests that is important. So to speed things up I want to use async workflows in F#, the idea being make your requests with 1 sec interval but avoid blocking things while waiting for request response. let getHtmlPrimitiveAsyncTimer (uri : System.Uri) (timer:int) = async{ let req = (WebRequest.Create(uri)) :?> HttpWebRequest req.UserAgent<-"Mozilla" try Thread.Sleep(timer) let! resp = (req.AsyncGetResponse()) Console.WriteLine(uri.AbsoluteUri+" got response") use stream = resp.GetResponseStream() use reader = new StreamReader(stream) let html = reader.ReadToEnd() return html with | _ as ex -> return "Bad Link" } Then I do something like: let uri1 = System.Uri "http://rue89.com" let timer = 1000 let jobs = [|for i in 1..10 -> getHtmlPrimitiveAsyncTimer uri1 timer|] jobs |> Array.mapi(fun i job -> Console.WriteLine("Starting job "+string i) Async.StartAsTask(job).Result) Is this alright ? I am very unsure about 2 things: -Does the Thread.Sleep thing work for delaying the request ? -Is using StartTask a problem ? I am a beginner (as you may have noticed) in F# (coding in general actually ), and everything envolving Threads scares me :) Thanks !!

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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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  • Abort SAX parsing mid-document?

    - by CSharperWithJava
    I'm parsing a very simple XML schema with a SAX parser in Android. An example file would be <Lists> <List name="foo"> <Note title="note 1" .../> <Note title="note 2" .../> </List> <List name="bar"> <Note title="note 3" .../> </List> </Lists> The ... represents more note data as attributes that aren't important to question. I use a SAX parser to parse the document and only implement the startElement and 'endElement' methods of the HandlerBase to handle Note and List nodes. However, In some cases the files can be very large and take some time to process. I'd like to be able to abort the parsing process at any time (i.e. user presses cancel button). The best way I've come up with is to throw an exception from my startElement method when certain conditions are met (i.e. boolean stopParsing is true). Is there a better way to do this? I've always used DOM style parsers, so I don't fully understand the SAX parser. One final note, I'm running this on Android, so I will have the Parser running on a worker thread to keep the UI responsive. If you know how I can kill the thread safely while the parser is running that would answer my question as well.

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  • Backwards compatibility when using Core Data

    - by Alex
    Could anybody shed some light as to why is my app crashing with the following error on iPhone OS 2.2.1 dyld: Symbol not found: _OBJC_CLASS_$_NSPredicate Referenced from: /var/mobile/Applications/456F243F-468A-4969-9BB7-A4DF993AE89C/AppName.app/AppName Expected in: /System/Library/Frameworks/Foundation.framework/Foundation I have weak linked CoreData.framework, and have the Base SDK set to 3.0 and Deployment Target set to SDK 2.2 The app already uses other 3.0 features when available and I did not have any problems with those. But apparently the backward-compatibility methods used for other features do not work with Core Data. The app crashes before app delegate's applicationDidFinishLaunching gets called. Here's the debugger log: [Session started at 2010-05-25 20:17:03 -0400.] GNU gdb 6.3.50-20050815 (Apple version gdb-1119) (Thu May 14 05:35:37 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys001 Loading program into debugger… sharedlibrary apply-load-rules all warning: Unable to read symbols from "MessageUI" (not yet mapped into memory). warning: Unable to read symbols from "CoreData" (not yet mapped into memory). Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-12038-42 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… [Switching to thread 10755] [Switching to thread 10755] Re-enabling shared library breakpoint 1 Re-enabling shared library breakpoint 2 Re-enabling shared library breakpoint 3 Re-enabling shared library breakpoint 4 Re-enabling shared library breakpoint 5 (gdb) continue warning: Unable to read symbols for ""/Users/alex/iPhone Projects/AppName/build/Debug-iphoneos"/AppName.app/AppName" (file not found). dyld: Symbol not found: _OBJC_CLASS_$_NSPredicate Referenced from: /var/mobile/Applications/456F243F-468A-4969-9BB7-A4DF993AE89C/AppName.app/AppName Expected in: /System/Library/Frameworks/Foundation.framework/Foundation (gdb)

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