libcamera: Provide a Request object

Implement a Request object used by applications to queue image capture
requests to a camera.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/camera.h

@@ -11,10 +11,12 @@
 #include <memory>
 #include <string>
 
+#include <libcamera/request.h>
 #include <libcamera/signal.h>
 
 namespace libcamera {
 
+class Buffer;
 class PipelineHandler;
 class Stream;
 class StreamConfiguration;
@@ -31,6 +33,7 @@ public:
 
 	const std::string &name() const;
 
+	Signal<Request *, const std::map<Stream *, Buffer *> &> requestCompleted;
 	Signal<Camera *> disconnected;
 
 	int acquire();

include/libcamera/libcamera.h

@@ -12,6 +12,7 @@
 #include <libcamera/camera_manager.h>
 #include <libcamera/event_dispatcher.h>
 #include <libcamera/event_notifier.h>
+#include <libcamera/request.h>
 #include <libcamera/signal.h>
 #include <libcamera/stream.h>
 #include <libcamera/timer.h>

include/libcamera/meson.build

@@ -5,6 +5,7 @@ libcamera_api = files([
     'event_dispatcher.h',
     'event_notifier.h',
     'libcamera.h',
+    'request.h',
     'signal.h',
     'stream.h',
     'timer.h',

include/libcamera/request.h

@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * request.h - Capture request handling
+ */
+#ifndef __LIBCAMERA_REQUEST_H__
+#define __LIBCAMERA_REQUEST_H__
+
+#include <map>
+#include <unordered_set>
+
+#include <libcamera/signal.h>
+
+namespace libcamera {
+
+class Buffer;
+class Camera;
+class Stream;
+
+class Request
+{
+public:
+	explicit Request(Camera *camera);
+	Request(const Request &) = delete;
+	Request &operator=(const Request &) = delete;
+
+	int setBuffers(const std::map<Stream *, Buffer *> &streamMap);
+	Buffer *findBuffer(Stream *stream) const;
+
+private:
+	friend class Camera;
+
+	int prepare();
+	void bufferCompleted(Buffer *buffer);
+
+	Camera *camera_;
+	std::map<Stream *, Buffer *> bufferMap_;
+	std::unordered_set<Buffer *> pending_;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_REQUEST_H__ */