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

[Kieran Bingham]

Hi Laurent

On 23/01/2020 02:55, Laurent Pinchart wrote:
> Add a parameter to the Thread::wait() function to wait with a timeout.
> The delay value waits forever.

I presume you mean

"No delay value waits forever"
 or
"The delay value utils::duration::max() waits forever."


With that fixed up,

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> 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
--
Kieran