Debugger: Start moving PdbEngine to common Gdb/Lldb base architecture

That's still not meant for "production", but just the "3rd use case
needed to get abstractions right".

For testing, remove all build steps, and use a custom run step
with executable /usr/bin/python and argument pointing to the
main .py file.

Change-Id: I6ae6ed08597896ea979ee58e73c546c7892e8be2
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/debugger/debuggerruncontrol.cpp

@@ -402,7 +402,7 @@ DebuggerRunControl *DebuggerRunControlFactory::doCreate
     }
 
     if (sp.masterEngineType == NoEngineType) {
-        if (sp.executable.endsWith(_(".py"))) {
+        if (sp.executable.endsWith(_(".py")) || sp.executable == _("/usr/bin/python")) {
             sp.masterEngineType = PdbEngineType;
         } else {
             if (RunConfiguration *rc = sp.runConfiguration) {

src/plugins/debugger/pdb/pdbengine.cpp

@@ -195,7 +195,7 @@ void PdbEngine::setupInferior()
 {
     QTC_ASSERT(state() == InferiorSetupRequested, qDebug() << state());
 
-    QString fileName = QFileInfo(startParameters().executable).absoluteFilePath();
+    QString fileName = mainPythonFile();
     QFile scriptFile(fileName);
     if (!scriptFile.open(QIODevice::ReadOnly|QIODevice::Text)) {
         Core::AsynchronousMessageBox::critical(tr("Python Error"),
@@ -207,17 +207,21 @@ void PdbEngine::setupInferior()
     notifyInferiorSetupOk();
 }
 
+QString PdbEngine::mainPythonFile() const
+{
+    return QFileInfo(startParameters().processArgs).absoluteFilePath();
+}
+
 void PdbEngine::runEngine()
 {
     QTC_ASSERT(state() == EngineRunRequested, qDebug() << state());
     showStatusMessage(tr("Running requested..."), 5000);
     const QByteArray dumperSourcePath =
         Core::ICore::resourcePath().toLocal8Bit() + "/debugger/";
-    QString fileName = QFileInfo(startParameters().executable).absoluteFilePath();
     postDirectCommand("import sys");
-    postDirectCommand("sys.argv.append('" + fileName.toLocal8Bit() + "')");
+    postDirectCommand("sys.argv.append('" + mainPythonFile().toLocal8Bit() + "')");
     postDirectCommand("execfile('/usr/bin/pdb')");
-    postDirectCommand("execfile('" + dumperSourcePath + "pdumper.py')");
+    postDirectCommand("execfile('" + dumperSourcePath + "pdbbridge.py')");
     attemptBreakpointSynchronization();
     notifyEngineRunAndInferiorStopOk();
     continueInferior();

src/plugins/debugger/pdb/pdbengine.h

@@ -108,6 +108,7 @@ private:
     bool supportsThreads() const { return true; }
     bool isSynchronous() const { return true; }
     void updateWatchData(const WatchData &data, const WatchUpdateFlags &flags);
+    QString mainPythonFile() const;
 
 signals:
     void outputReady(const QByteArray &data);