[libcamera-devel] [PATCH 1/2] libcamera: thread: Support timeout in wait() function

[Laurent Pinchart]

Add a parameter to the Thread::wait() function to wait with a timeout.
The delay value waits forever.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 src/libcamera/include/thread.h |  4 +++-
 src/libcamera/thread.cpp       | 28 +++++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/libcamera/include/thread.h b/src/libcamera/include/thread.h
index 819a9879ac56..d700f111a3ae 100644
--- a/src/libcamera/include/thread.h
+++ b/src/libcamera/include/thread.h
@@ -14,6 +14,8 @@
 
 #include <libcamera/signal.h>
 
+#include "utils.h"
+
 namespace libcamera {
 
 class EventDispatcher;
@@ -33,7 +35,7 @@ public:
 
 	void start();
 	void exit(int code = 0);
-	void wait();
+	bool wait(utils::duration duration = utils::duration::max());
 
 	bool isRunning();
 
diff --git a/src/libcamera/thread.cpp b/src/libcamera/thread.cpp
index fe32cd677596..22ab41f847db 100644
--- a/src/libcamera/thread.cpp
+++ b/src/libcamera/thread.cpp
@@ -8,6 +8,7 @@
 #include "thread.h"
 
 #include <atomic>
+#include <condition_variable>
 #include <list>
 #include <unistd.h>
 #include <sys/syscall.h>
@@ -71,6 +72,7 @@ private:
 
 	std::atomic<EventDispatcher *> dispatcher_;
 
+	std::condition_variable cv_;
 	std::atomic<bool> exit_;
 	int exitCode_;
 
@@ -248,6 +250,7 @@ void Thread::finishThread()
 	data_->mutex_.unlock();
 
 	finished.emit(this);
+	data_->cv_.notify_all();
 }
 
 /**
@@ -274,14 +277,33 @@ void Thread::exit(int code)
 
 /**
  * \brief Wait for the thread to finish
+ * \param[in] duration Maximum wait duration
  *
- * This method waits until the thread finishes, or returns immediately if the
- * thread is not running.
+ * This function waits until the thread finishes or the \a duration has
+ * elapsed, whichever happens first. If \a duration is equal to
+ * utils::duration::max(), the wait never times out. If the thread is not
+ * running the function returns immediately.
+ *
+ * \return True if the thread has finished, or false if the wait timed out
  */
-void Thread::wait()
+bool Thread::wait(utils::duration duration)
 {
+	bool timeout = false;
+
+	{
+		MutexLocker locker(data_->mutex_);
+
+		if (duration == utils::duration::max())
+			data_->cv_.wait(locker, [&]() { return !data_->running_; });
+		else
+			timeout = !data_->cv_.wait_for(locker, duration,
+						       [&]() { return !data_->running_; });
+	}
+
 	if (thread_.joinable())
 		thread_.join();
+
+	return timeout;
 }
 
 /**
-- 
Regards,

Laurent Pinchart