Add restart limiter to OverlayPrivateWin to avoid bombing the system with process spawns.

We need this in case there's a bug in one of the overlay helpers.
Without this, we would restart a crashed helper immediately. If this
bug is triggered every time the helper is run, we'd get into an infinite
restart loop, potentially making the host computer unresponsive.

src/mumble/Overlay_win.cpp

@@ -88,6 +88,10 @@ OverlayPrivateWin::OverlayPrivateWin(QObject *p) : OverlayPrivate(p) {
 	connect(m_helper_process, SIGNAL(finished(int, QProcess::ExitStatus)),
 	        this, SLOT(onHelperProcessExited(int, QProcess::ExitStatus)));
 
+	m_helper_restart_timer = new QTimer(this);
+	m_helper_restart_timer->setSingleShot(true);
+	connect(m_helper_restart_timer, SIGNAL(timeout()), this, SLOT(onDelayedRestartTimerTriggered()));
+
 	m_helper64_exe_path = QString::fromLatin1("%1/mumble_ol_x64.exe").arg(qApp->applicationDirPath());
 	m_helper64_exe_args = m_helper_exe_args;
 	m_helper64_process = new QProcess(this);
@@ -100,6 +104,10 @@ OverlayPrivateWin::OverlayPrivateWin(QObject *p) : OverlayPrivate(p) {
 
 	connect(m_helper64_process, SIGNAL(finished(int, QProcess::ExitStatus)),
 	        this, SLOT(onHelperProcessExited(int, QProcess::ExitStatus)));
+
+	m_helper64_restart_timer = new QTimer(this);
+	m_helper64_restart_timer->setSingleShot(true);
+	connect(m_helper64_restart_timer, SIGNAL(timeout()), this, SLOT(onDelayedRestartTimerTriggered()));
 }
 
 OverlayPrivateWin::~OverlayPrivateWin() {
@@ -110,8 +118,10 @@ void OverlayPrivateWin::startHelper(QProcess *helper) {
 	if (helper->state() == QProcess::NotRunning) {
 		if (helper == m_helper_process) {
 			helper->start(m_helper_exe_path, m_helper_exe_args);
+			m_helper_start_time.restart();
 		} else if (helper == m_helper64_process) {
 			helper->start(m_helper64_exe_path, m_helper64_exe_args);
+			m_helper64_start_time.restart();
 		}
 	} else {
 		qWarning("OverlayPrivateWin: startHelper() called while process is already running. skipping.");
@@ -194,11 +204,18 @@ void OverlayPrivateWin::onHelperProcessError(QProcess::ProcessError processError
 
 void OverlayPrivateWin::onHelperProcessExited(int exitCode, QProcess::ExitStatus exitStatus) {
 	QProcess *helper = qobject_cast<QProcess *>(sender());
+
 	QString path;
+	qint64 elapsedMsec;
+	QTimer *restartTimer;
 	if (helper == m_helper_process) {
 		path = m_helper_exe_path;
+		elapsedMsec = m_helper_start_time.elapsed();
+		restartTimer = m_helper_restart_timer;
 	} else if (helper == m_helper64_process) {
 		path = m_helper64_exe_path;
+		elapsedMsec = m_helper64_start_time.elapsed();
+		restartTimer = m_helper64_restart_timer;
 	}
 
 	const char *helperErrString = OverlayHelperErrorToString(static_cast<OverlayHelperError>(exitCode));
@@ -210,7 +227,43 @@ void OverlayPrivateWin::onHelperProcessExited(int exitCode, QProcess::ExitStatus
 	// If the helper process exited while we're in 'active'
 	// mode, restart it.
 	if (m_active) {
+		// If the helper was only recently started, be
+		// a little more patient with restarting it.
+		// We could be hitting a crash bug in the helper,
+		// and we don't want to do too much harm in that
+		// case by spawning thousands of processes.
+		qint64 cooldownMsec = (qint64) g.s.iOverlayWinHelperRestartCooldownMsec;
+		if (elapsedMsec < cooldownMsec) {
+			qint64 delayMsec = cooldownMsec - elapsedMsec;
+			qWarning("OverlayPrivateWin: waiting %llu seconds until restarting helper process '%s'. last restart was %llu seconds ago.",
+				(unsigned long long) delayMsec/1000ULL,
+				qPrintable(path),
+				(unsigned long long) elapsedMsec/1000ULL);
+			if (!restartTimer->isActive()) {
+				restartTimer->start(delayMsec);
+			}
+		} else {
 			startHelper(helper);
+		}
+	}
+}
+
+void OverlayPrivateWin::onDelayedRestartTimerTriggered() {
+	if (!m_active) {
+		return;
+	}
+
+	QTimer *timer = qobject_cast<QTimer *>(sender());
+
+	QProcess *helper = NULL;
+	if (timer == m_helper_restart_timer) {
+		helper = m_helper_process;
+	} else if (timer == m_helper64_restart_timer) {
+		helper = m_helper64_process;
+	}
+
+	if (helper->state() == QProcess::NotRunning) {
+		startHelper(helper);
 	}
 }
 

src/mumble/Overlay_win.h

@@ -35,6 +35,8 @@
 #include <QString>
 #include <QStringList>
 #include <QProcess>
+#include <QTimer>
+#include <QElapsedTimer>
 
 #include "Overlay.h"
 
@@ -52,15 +54,20 @@ class OverlayPrivateWin : public OverlayPrivate {
 		void onHelperProcessStarted();
 		void onHelperProcessError(QProcess::ProcessError);
 		void onHelperProcessExited(int exitCode, QProcess::ExitStatus exitStatus);
+		void onDelayedRestartTimerTriggered();
 
 	protected:
 		QProcess *m_helper_process;
 		QString m_helper_exe_path;
 		QStringList m_helper_exe_args;
+		QElapsedTimer m_helper_start_time;
+		QTimer *m_helper_restart_timer;
 
 		QProcess *m_helper64_process;
 		QString m_helper64_exe_path;
 		QStringList m_helper64_exe_args;
+		QElapsedTimer m_helper64_start_time;
+		QTimer *m_helper64_restart_timer;
 
 		bool m_active;
 		bool m_allow64bit;

src/mumble/Settings.cpp

@@ -345,6 +345,9 @@ Settings::Settings() {
 	fAudioMaxDistVolume = 0.80f;
 	fAudioBloom = 0.5f;
 
+	// OverlayPrivateWin
+	iOverlayWinHelperRestartCooldownMsec = 10000;
+
 	iLCDUserViewMinColWidth = 50;
 	iLCDUserViewSplitterWidth = 2;
 
@@ -696,7 +699,9 @@ void Settings::load(QSettings* settings_ptr) {
 	SAVELOAD(bDisableCELT, "audio/disablecelt");
 	SAVELOAD(disablePublicList, "ui/disablepubliclist");
 	SAVELOAD(disableConnectDialogEditing, "ui/disableconnectdialogediting");
-	
+
+	// OverlayPrivateWin
+	SAVELOAD(iOverlayWinHelperRestartCooldownMsec, "overlay_win/helper/restart_cooldown_msec");
 
 	// LCD
 	SAVELOAD(iLCDUserViewMinColWidth, "lcd/userview/mincolwidth");
@@ -990,6 +995,9 @@ void Settings::save() {
 	SAVELOAD(disablePublicList, "ui/disablepubliclist");
 	SAVELOAD(disableConnectDialogEditing, "ui/disableconnectdialogediting");
 
+	// OverlayPrivateWin
+	SAVELOAD(iOverlayWinHelperRestartCooldownMsec, "overlay_win/helper/restart_cooldown_msec");
+
 	// LCD
 	SAVELOAD(iLCDUserViewMinColWidth, "lcd/userview/mincolwidth");
 	SAVELOAD(iLCDUserViewSplitterWidth, "lcd/userview/splitterwidth");

src/mumble/Settings.h

@@ -230,6 +230,8 @@ struct Settings {
 
 	OverlaySettings os;
 
+	int iOverlayWinHelperRestartCooldownMsec;
+
 	int iLCDUserViewMinColWidth;
 	int iLCDUserViewSplitterWidth;
 	QMap<QString, bool> qmLCDDevices;