libcamera: base: Introduce ConditionVariable

ConditionVariable is alias to std::condition_variable. This replaces
std::condition_variable with the ConditionVariable. It enables
replacing ConditionVariable implementation easily in the following
patches.

Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/base/semaphore.h

@@ -7,8 +7,6 @@
 
 #pragma once
 
-#include <condition_variable>
-
 #include <libcamera/base/private.h>
 #include <libcamera/base/thread.h>
 
@@ -26,7 +24,7 @@ public:
 
 private:
 	Mutex mutex_;
-	std::condition_variable cv_;
+	ConditionVariable cv_;
 	unsigned int available_;
 };
 

include/libcamera/base/thread.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <condition_variable>
 #include <memory>
 #include <mutex>
 #include <sys/types.h>
@@ -26,6 +27,7 @@ class Object;
 class ThreadData;
 class ThreadMain;
 
+using ConditionVariable = std::condition_variable;
 using Mutex = std::mutex;
 using MutexLocker = std::unique_lock<std::mutex>;
 

src/android/camera_stream.h

@@ -7,7 +7,6 @@
 
 #pragma once
 
-#include <condition_variable>
 #include <memory>
 #include <mutex>
 #include <queue>
@@ -154,7 +153,7 @@ private:
 		PostProcessor *postProcessor_;
 
 		libcamera::Mutex mutex_;
-		std::condition_variable cv_;
+		libcamera::ConditionVariable cv_;
 
 		std::queue<Camera3RequestDescriptor::StreamBuffer *> requests_;
 		State state_ = State::Stopped;

src/libcamera/base/thread.cpp

@@ -8,7 +8,6 @@
 #include <libcamera/base/thread.h>
 
 #include <atomic>
-#include <condition_variable>
 #include <list>
 #include <sys/syscall.h>
 #include <sys/types.h>
@@ -158,7 +157,7 @@ private:
 
 	std::atomic<EventDispatcher *> dispatcher_;
 
-	std::condition_variable cv_;
+	ConditionVariable cv_;
 	std::atomic<bool> exit_;
 	int exitCode_;
 
@@ -205,6 +204,11 @@ ThreadData *ThreadData::current()
 	return data;
 }
 
+/**
+ * \typedef ConditionVariable
+ * \brief An alias for std::condition_variable
+ */
+
 /**
  * \typedef Mutex
  * \brief An alias for std::mutex

src/libcamera/camera_manager.cpp

@@ -7,7 +7,6 @@
 
 #include <libcamera/camera_manager.h>
 
-#include <condition_variable>
 #include <map>
 
 #include <libcamera/camera.h>
@@ -63,7 +62,7 @@ private:
 	void createPipelineHandlers();
 	void cleanup();
 
-	std::condition_variable cv_;
+	ConditionVariable cv_;
 	bool initialized_;
 	int status_;
 

src/v4l2/v4l2_camera.h

@@ -82,6 +82,6 @@ private:
 	int efd_;
 
 	libcamera::Mutex bufferMutex_;
-	std::condition_variable bufferCV_;
+	libcamera::ConditionVariable bufferCV_;
 	unsigned int bufferAvailableCount_;
 };