Multiprocessing support

However several drawbacks:
- No text output from inner process. (If using threading class instead; there is an output)
- Terminate() crashes the whole program. (Using threading, one cannot stop the thread easily)

src/main-window.cc

@@ -733,8 +733,7 @@ void CMainWindow::cancelProcess()
 {
     if (future.isRunning())
     {
-        qDebug() << "Stopping process";
-        // TODO: Implement cancelation through python
+        m_builder->stopBuilding();
     }
 }
 

src/make-songbook-process.cc

@@ -57,34 +57,30 @@ void CMakeSongbookProcess::stdErr(QString string)
 {
     // Hack to simplify output
     if (!string.simplified().isEmpty()) {
-        qWarning() << string.simplified().toUtf8().constData();
+        emit message("PY: " + string.simplified(),0);
+        // qWarning() << string.simplified().toUtf8().constData();
     }
 }
 
 void CMakeSongbookProcess::execute()
 {
-    /*
-    // TESTING TESTING TESTING
-    qDebug() << "++++++";
-    QString script = QString::fromLatin1("print('é')");
-    pythonModule.evalScript(script);
-    */
-
     emit(aboutToStart());
     if (!m_songbook->filename().isEmpty()) {
         // pythonModule.evalScript(QString("setupSongbook('%1','%2')").arg(m_songbook,m_datadirs.first()));
         // pythonModule.evalScript("build(['tex', 'pdf', 'sbx', 'pdf', 'clean'])");
         // Expose Songbook to python
         pythonModule.addObject("songbook", m_songbook);
+        pythonModule.addObject("CPPprocess", this);
         pythonModule.evalScript("print(songbook.filename)");
         pythonModule.evalScript("setupSongbook(songbook.filename,'" + m_datadirs.first() + "')");
         pythonModule.evalScript("build(['tex', 'pdf', 'sbx', 'pdf', 'clean'])");
-        pythonModule.removeVariable("songbook");
+        // pythonModule.removeVariable("songbook");
         emit(message("Finished Execution",0));
         emit(finished());
     }
     else{
         emit(message("Error: no songbook loaded",0));
+        emit(finished());
     }
 }
 
@@ -127,7 +123,11 @@ void CMakeSongbookProcess::setWorkingDirectory(const QString &dir)
 {
     // TODO Do Something ?
     pythonModule.evalScript("os.chdir('" + dir + "')");
-    pythonModule.evalScript("print('CWD: ' + os.getcwd())");
+}
+
+void CMakeSongbookProcess::stopBuilding()
+{
+    pythonModule.evalScript("stopBuild()");
 }
 
 const CSongbook* CMakeSongbookProcess::songbook() const

src/make-songbook-process.hh

@@ -110,6 +110,11 @@ public slots:
   */
     void setUrlToOpen(const QUrl &url);
 
+   /*!
+    Stop the build
+  */
+    void stopBuilding();
+
 public:
     /// Constructor.
     CMakeSongbookProcess(QObject *parent = 0);

src/songbook.py

@@ -7,6 +7,8 @@
 import os.path
 import textwrap
 import sys
+import logging
+import multiprocessing
 
 # Import patacrep modules
 from patacrep.build import SongbookBuilder, DEFAULT_STEPS
@@ -19,6 +21,7 @@
 
 # Define global variables
 sb_builder = None
+process = None
 
 # Define locale according to user's parameters
 def setLocale():
@@ -76,10 +79,32 @@ def setupSongbook(songbook_path,datadir):
         # Deal with error
 
 def build(steps):
+    global process
+    process = multiprocessing.Process(target=buildSongbook, args=(steps,))
+    try:
+        #logger.info('Starting process')
+        process.start()
+    except multiprocessing.ProcessError as error:
+        #logger.warning('process Error occured')
+        message(error)
+    process.join()
+
+def message(text):
+    CPPprocess.message(text,0)
+
+def buildSongbook(steps):
+    message("Inner Function Reached")
+    sys.stdout.flush()
     global sb_builder
     try:
+        message("Building songbook")
         sb_builder.build_steps(steps)
     except errors.SongbookError as error:
-        print("Building error")
-        print(error)
-        # Deal with error
+        message("Building error")
+        # Call proper function in CPPprocess
+        message(error)
+
+def stopBuild():
+    message("Terminating process")
+    global process
+    process.terminate()