##// END OF EJS Templates
Backport PR #2294: inputhook_qt4: Use QEventLoop instead of starting up the QCoreApplication...
Backport PR #2294: inputhook_qt4: Use QEventLoop instead of starting up the QCoreApplication I referenced this branch in #2080 and was letting it sit for a little while, but I have decided to make it a full pull request to get some additional visibility. Essentially our Qt event loop mechanism repeatedly starts and quits a `QCoreApplication` object. Unfortunately the `QCoreApplication::quit` slot has a lot of unintended side effects (like emitting an `aboutToQuit` signal which closes all open file dialogs). For our input hook, we _might_ be able to get by with just using a `QEventLoop` whose quit slot is much simpler and less destructive. For a little bit of background on why one might want to just use `QEventLoop::exec`, let's examine what `QCoreApplication::exec` does: ```c++ int QCoreApplication::exec() { if (!QCoreApplicationPrivate::checkInstance("exec")) return -1; // ... [some assertions] threadData->quitNow = false; QEventLoop eventLoop; self->d_func()->in_exec = true; self->d_func()->aboutToQuitEmitted = false; int returnCode = eventLoop.exec(); threadData->quitNow = false; if (self) { self->d_func()->in_exec = false; if (!self->d_func()->aboutToQuitEmitted) emit self->aboutToQuit(); self->d_func()->aboutToQuitEmitted = true; sendPostedEvents(0, QEvent::DeferredDelete); } return returnCode; } ``` As far as I can tell, it's a small wrapper around `QEventLoop::exec` which also: * Sets some variables regarding the current status * Emits an `aboutToQuit` signal right before the function returns (which is the root cause of @denisri's problem in #2080). Historically, our Qt event loop is a python implementation of the (win 32) input hook supplied with the PyQt4 source (see qtcore_input_hook` in `python-qt4/sip/QtCore/qcoreapplication.sip`), which more or less dates to a [mailing list post](http://www.riverbankcomputing.com/pipermail/pyqt/2007-July/016512.html) from July 2007.

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main.m
49 lines | 1.8 KiB | text/octave | ObjectiveCLexer
//
// main.m
// IPython1Sandbox
//
// Created by Barry Wark on 3/4/08.
// Copyright __MyCompanyName__ 2008. All rights reserved.
//
#import <Python/Python.h>
#import <Cocoa/Cocoa.h>
int main(int argc, char *argv[])
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSBundle *mainBundle = [NSBundle mainBundle];
NSString *resourcePath = [mainBundle resourcePath];
NSArray *pythonPathArray = [NSArray arrayWithObjects: resourcePath, [resourcePath stringByAppendingPathComponent:@"PyObjC"], nil];
setenv("PYTHONPATH", [[pythonPathArray componentsJoinedByString:@":"] UTF8String], 1);
NSArray *possibleMainExtensions = [NSArray arrayWithObjects: @"py", @"pyc", @"pyo", nil];
NSString *mainFilePath = nil;
for (NSString *possibleMainExtension in possibleMainExtensions) {
mainFilePath = [mainBundle pathForResource: @"main" ofType: possibleMainExtension];
if ( mainFilePath != nil ) break;
}
if ( !mainFilePath ) {
[NSException raise: NSInternalInconsistencyException format: @"%s:%d main() Failed to find the Main.{py,pyc,pyo} file in the application wrapper's Resources directory.", __FILE__, __LINE__];
}
Py_SetProgramName("/usr/bin/python");
Py_Initialize();
PySys_SetArgv(argc, (char **)argv);
const char *mainFilePathPtr = [mainFilePath UTF8String];
FILE *mainFile = fopen(mainFilePathPtr, "r");
int result = PyRun_SimpleFile(mainFile, (char *)[[mainFilePath lastPathComponent] UTF8String]);
if ( result != 0 )
[NSException raise: NSInternalInconsistencyException
format: @"%s:%d main() PyRun_SimpleFile failed with file '%@'. See console for errors.", __FILE__, __LINE__, mainFilePath];
[pool drain];
return result;
}