AbstractProcessStep: Do not run a qprocess in a thread

This avoids sending signals for new tasks and process output
via the gui thread's event loop. When finding lots of issues in
the output we generate so many events that any attempt to
compress events takes a long time (max. events waiting to be
processed were > 1200000 when doing a clang -Weverything build!),
and thus the UI freezes.

Change-Id: I9668d2537b1a268e788cd0ea5c756ebaab4462a9
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

1 files changed, 27 insertions, 23 deletions

diff --git a/src/plugins/projectexplorer/abstractprocessstep.cpp b/src/plugins/projectexplorer/abstractprocessstep.cpp
index 95d8729018..2aaf5b6931 100644
--- a/src/plugins/projectexplorer/abstractprocessstep.cpp
+++ b/src/plugins/projectexplorer/abstractprocessstep.cpp
@@ -91,7 +91,7 @@ using namespace ProjectExplorer;
 AbstractProcessStep::AbstractProcessStep(BuildStepList *bsl, const Core::Id id) :
     BuildStep(bsl, id), m_timer(0), m_futureInterface(0),
     m_ignoreReturnValue(false), m_process(0),
-    m_eventLoop(0), m_outputParserChain(0)
+    m_outputParserChain(0)
 {
 }
 
@@ -99,7 +99,7 @@ AbstractProcessStep::AbstractProcessStep(BuildStepList *bsl,
                                          AbstractProcessStep *bs) :
     BuildStep(bsl, bs), m_timer(0), m_futureInterface(0),
     m_ignoreReturnValue(bs->m_ignoreReturnValue),
-    m_process(0), m_eventLoop(0), m_outputParserChain(0)
+    m_process(0), m_outputParserChain(0)
 {
 }
 
@@ -197,15 +197,12 @@ void AbstractProcessStep::run(QFutureInterface<bool> &fi)
     m_process->setEnvironment(m_param.environment());
 
     connect(m_process, SIGNAL(readyReadStandardOutput()),
-            this, SLOT(processReadyReadStdOutput()),
-            Qt::DirectConnection);
+            this, SLOT(processReadyReadStdOutput()));
     connect(m_process, SIGNAL(readyReadStandardError()),
-            this, SLOT(processReadyReadStdError()),
-            Qt::DirectConnection);
+            this, SLOT(processReadyReadStdError()));
 
     connect(m_process, SIGNAL(finished(int,QProcess::ExitStatus)),
-            this, SLOT(slotProcessFinished(int,QProcess::ExitStatus)),
-            Qt::DirectConnection);
+            this, SLOT(slotProcessFinished(int,QProcess::ExitStatus)));
 
     m_process->setCommand(m_param.effectiveCommand(), m_param.effectiveArguments());
     m_process->start();
@@ -214,19 +211,19 @@ void AbstractProcessStep::run(QFutureInterface<bool> &fi)
         delete m_process;
         m_process = 0;
         fi.reportResult(false);
+        emit finished();
         return;
     }
     processStarted();
 
     m_timer = new QTimer();
-    connect(m_timer, SIGNAL(timeout()), this, SLOT(checkForCancel()), Qt::DirectConnection);
+    connect(m_timer, SIGNAL(timeout()), this, SLOT(checkForCancel()));
     m_timer->start(500);
-    m_eventLoop = new QEventLoop;
-    m_eventLoop->exec();
-    m_timer->stop();
-    delete m_timer;
-    m_timer = 0;
+    m_killProcess = false;
+}
 
+void AbstractProcessStep::cleanUp()
+{
     // The process has finished, leftover data is read in processFinished
     processFinished(m_process->exitCode(), m_process->exitStatus());
     bool returnValue = processSucceeded(m_process->exitCode(), m_process->exitStatus()) || m_ignoreReturnValue;
@@ -239,11 +236,10 @@ void AbstractProcessStep::run(QFutureInterface<bool> &fi)
 
     delete m_process;
     m_process = 0;
-    delete m_eventLoop;
-    m_eventLoop = 0;
-    fi.reportResult(returnValue);
+    m_futureInterface->reportResult(returnValue);
     m_futureInterface = 0;
-    return;
+
+    emit finished();
 }
 
 /*!
@@ -351,10 +347,14 @@ void AbstractProcessStep::stdError(const QString &line)
 void AbstractProcessStep::checkForCancel()
 {
     if (m_futureInterface->isCanceled() && m_timer->isActive()) {
-        m_timer->stop();
-        m_process->terminate();
-        m_process->waitForFinished(5000);
-        m_process->kill();
+        if (!m_killProcess) {
+            m_process->terminate();
+            m_timer->start(5000);
+            m_killProcess = true;
+        } else {
+            m_process->kill();
+            m_timer->stop();
+        }
     }
 }
 
@@ -413,6 +413,10 @@ void AbstractProcessStep::outputAdded(const QString &string, ProjectExplorer::Bu
 
 void AbstractProcessStep::slotProcessFinished(int, QProcess::ExitStatus)
 {
+    m_timer->stop();
+    delete m_timer;
+    m_timer = 0;
+
     QString line = QString::fromLocal8Bit(m_process->readAllStandardError());
     if (!line.isEmpty())
         stdError(line);
@@ -421,5 +425,5 @@ void AbstractProcessStep::slotProcessFinished(int, QProcess::ExitStatus)
     if (!line.isEmpty())
         stdOutput(line);
 
-    m_eventLoop->exit(0);
+    cleanUp();
 }