android: Introduce PlatformFrameBufferAllocator

The existing FrameBufferAllocator is not allowed to allocate a
new buffer while Camera is running. This introduces
PlatformFrameBufferAllocator. It allocates FrameBuffer using
cros::CameraBufferManager on ChromeOS and gralloc on non ChromeOS
platform. The allocated FrameBuffer owns the underlying buffer
but must be destroyed before PlatformFrameBufferAllocator is
destroyed.

Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

src/android/frame_buffer_allocator.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Google Inc.
+ *
+ * frame_buffer_allocator.h - Interface definition to allocate Frame buffer in
+ * platform dependent way.
+ */
+#ifndef __ANDROID_FRAME_BUFFER_ALLOCATOR_H__
+#define __ANDROID_FRAME_BUFFER_ALLOCATOR_H__
+
+#include <memory>
+
+#include <libcamera/base/class.h>
+
+#include <libcamera/camera.h>
+#include <libcamera/framebuffer.h>
+#include <libcamera/geometry.h>
+
+class CameraDevice;
+
+class PlatformFrameBufferAllocator : libcamera::Extensible
+{
+	LIBCAMERA_DECLARE_PRIVATE()
+
+public:
+	explicit PlatformFrameBufferAllocator(CameraDevice *const cameraDevice);
+	~PlatformFrameBufferAllocator();
+
+	/*
+	 * FrameBuffer owns the underlying buffer. Returns nullptr on failure.
+	 * Note: The returned FrameBuffer needs to be destroyed before
+	 * PlatformFrameBufferAllocator is destroyed.
+	 */
+	std::unique_ptr<libcamera::FrameBuffer> allocate(
+		int halPixelFormat, const libcamera::Size &size, uint32_t usage);
+};
+
+#define PUBLIC_FRAME_BUFFER_ALLOCATOR_IMPLEMENTATION			\
+PlatformFrameBufferAllocator::PlatformFrameBufferAllocator(		\
+	CameraDevice *const cameraDevice)				\
+	: Extensible(std::make_unique<Private>(cameraDevice))		\
+{									\
+}									\
+PlatformFrameBufferAllocator::~PlatformFrameBufferAllocator()		\
+{									\
+}									\
+std::unique_ptr<libcamera::FrameBuffer>					\
+PlatformFrameBufferAllocator::allocate(int halPixelFormat,		\
+				       const libcamera::Size &size,	\
+				       uint32_t usage)			\
+{									\
+	return _d()->allocate(halPixelFormat, size, usage);		\
+}
+
+#endif /* __ANDROID_FRAME_BUFFER_ALLOCATOR_H__ */