libcamera: request: Add request completion status

Add a new field to the Request class to report its completion status,
and a new complete() method to update the status.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/request.h

@@ -18,9 +18,16 @@ class Buffer;
 class Camera;
 class Stream;
 
+
 class Request
 {
 public:
+	enum Status {
+		RequestPending,
+		RequestComplete,
+		RequestCancelled,
+	};
+
 	explicit Request(Camera *camera);
 	Request(const Request &) = delete;
 	Request &operator=(const Request &) = delete;
@@ -28,15 +35,20 @@ public:
 	int setBuffers(const std::map<Stream *, Buffer *> &streamMap);
 	Buffer *findBuffer(Stream *stream) const;
 
+	Status status() const { return status_; }
+
 private:
 	friend class Camera;
 
 	int prepare();
+	void complete(Status status);
 	void bufferCompleted(Buffer *buffer);
 
 	Camera *camera_;
 	std::map<Stream *, Buffer *> bufferMap_;
 	std::unordered_set<Buffer *> pending_;
+
+	Status status_;
 };
 
 } /* namespace libcamera */

src/libcamera/request.cpp

@@ -23,6 +23,17 @@ namespace libcamera {
 
 LOG_DEFINE_CATEGORY(Request)
 
+/**
+ * \enum Request::Status
+ * Request completion status
+ * \var Request::RequestPending
+ * The request hasn't completed yet
+ * \var Request::RequestComplete
+ * The request has completed
+ * \var Request::RequestCancelled
+ * The request has been cancelled due to capture stop
+ */
+
 /**
  * \class Request
  * \brief A frame capture request
@@ -36,7 +47,7 @@ LOG_DEFINE_CATEGORY(Request)
  * \param[in] camera The camera that creates the request
  */
 Request::Request(Camera *camera)
-	: camera_(camera)
+	: camera_(camera), status_(RequestPending)
 {
 }
 
@@ -82,6 +93,19 @@ Buffer *Request::findBuffer(Stream *stream) const
 	return it->second;
 }
 
+/**
+ * \fn Request::status()
+ * \brief Retrieve the request completion status
+ *
+ * The request status indicates whether the request has completed successfully
+ * or with an error. When requests are created and before they complete the
+ * request status is set to RequestPending, and is updated at completion time
+ * to RequestComplete. If a request is cancelled at capture stop before it has
+ * completed, its status is set to RequestCancelled.
+ *
+ * \return The request completion status
+ */
+
 /**
  * \brief Prepare the resources for the completion handler
  */
@@ -96,6 +120,18 @@ int Request::prepare()
 	return 0;
 }
 
+/**
+ * \brief Complete a queued request
+ * \param[in] status The request completion status
+ *
+ * Mark the request as complete by updating its status to \a status.
+ */
+void Request::complete(Status status)
+{
+	ASSERT(pending_.empty());
+	status_ = status;
+}
+
 /**
  * \brief Slot for the buffer completed signal
  *
@@ -117,6 +153,8 @@ void Request::bufferCompleted(Buffer *buffer)
 	if (!pending_.empty())
 		return;
 
+	complete(RequestComplete);
+
 	std::map<Stream *, Buffer *> buffers(std::move(bufferMap_));
 	camera_->requestCompleted.emit(this, buffers);
 	delete this;