QmlDesigner: create error output file for puppet builds

Change-Id: I140820702d11e5bc20e6063bdee13411a5f2eeaa
Reviewed-by: Tim Jenssen <tim.jenssen@theqtcompany.com>

src/plugins/qmldesigner/designercore/instances/puppetbuildprogressdialog.cpp

@@ -67,6 +67,12 @@ bool PuppetBuildProgressDialog::useFallbackPuppet() const
     return m_useFallbackPuppet;
 }
 
+void PuppetBuildProgressDialog::setErrorOutputFile(const QString &filePath)
+{
+    ui->openErrorOutputFileLabel->setText(QString::fromLatin1("<a href='file:///%1'>%2</a>").arg(
+        filePath, ui->openErrorOutputFileLabel->text()));
+}
+
 void PuppetBuildProgressDialog::setUseFallbackPuppet()
 {
     m_useFallbackPuppet = true;

src/plugins/qmldesigner/designercore/instances/puppetbuildprogressdialog.h

@@ -51,6 +51,7 @@ public:
     void setProgress(int progress);
     void newBuildOutput(const QByteArray &standardOutput);
     bool useFallbackPuppet() const;
+    void setErrorOutputFile(const QString &filePath);
 
 private slots:
     void setUseFallbackPuppet();

src/plugins/qmldesigner/designercore/instances/puppetcreator.cpp

@@ -391,21 +391,31 @@ bool PuppetCreator::startBuildProcess(const QString &buildDirectoryPath,
     if (command.isEmpty())
         return false;
 
+    const QString errorOutputFilePath(buildDirectoryPath + QLatin1String("/build_error_output.txt"));
+    if (QFile::exists(errorOutputFilePath))
+        QFile(errorOutputFilePath).remove();
+    progressDialog->setErrorOutputFile(errorOutputFilePath);
+
     QProcess process;
+    process.setStandardErrorFile(errorOutputFilePath);
     process.setProcessChannelMode(QProcess::SeparateChannels);
     process.setProcessEnvironment(processEnvironment());
     process.setWorkingDirectory(buildDirectoryPath);
     process.start(command, processArguments);
     process.waitForStarted();
-    while (process.waitForReadyRead(-1)) {
+    while (process.waitForReadyRead(100) || process.state() == QProcess::Running) {
         if (progressDialog->useFallbackPuppet())
             return false;
 
+        QApplication::processEvents(QEventLoop::ExcludeSocketNotifiers);
+
         QByteArray newOutput = process.readAllStandardOutput();
-        if (progressDialog)
-            progressDialog->newBuildOutput(newOutput);
+        if (!newOutput.isEmpty()) {
+            if (progressDialog)
+                progressDialog->newBuildOutput(newOutput);
 
-        m_compileLog.append(newOutput);
+            m_compileLog.append(QString::fromLatin1(newOutput));
+        }
     }
 
     process.waitForFinished();