From eb4030f6c07174a520be1ebd73628e9ae4789569 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niklas=20S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>
Date: Sun, 27 Oct 2019 22:10:25 +0100
Subject: libcamera: allocator: Add FrameBufferAllocator to help applications
 allocate buffers
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The FrameBuffer interface is based on the idea that all buffers are
allocated externally to libcamera and are only used by it. This is meant
to create a simpler API centered around usage of buffers, regardless of
where they come from.

Linux however lacks a centralized allocator at the moment, and not all
users of libcamera are expected to use another device that could provide
suitable buffers for the camera. This patch thus adds a helper class to
allocate buffers internally in libcamera, in a way that matches the
needs of the FrameBuffer-based API.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 include/libcamera/camera.h                |  5 ++++
 include/libcamera/framebuffer_allocator.h | 45 +++++++++++++++++++++++++++++++
 include/libcamera/meson.build             |  1 +
 3 files changed, 51 insertions(+)
 create mode 100644 include/libcamera/framebuffer_allocator.h

(limited to 'include')

diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index ef6a37bb..2fd5870b 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -20,6 +20,7 @@
 namespace libcamera {
 
 class Buffer;
+class FrameBufferAllocator;
 class PipelineHandler;
 class Request;
 
@@ -126,6 +127,10 @@ private:
 
 	bool disconnected_;
 	State state_;
+
+	/* Needed to update allocator_ and to read state_ and activeStreams_. */
+	friend class FrameBufferAllocator;
+	FrameBufferAllocator *allocator_;
 };
 
 } /* namespace libcamera */
diff --git a/include/libcamera/framebuffer_allocator.h b/include/libcamera/framebuffer_allocator.h
new file mode 100644
index 00000000..42812253
--- /dev/null
+++ b/include/libcamera/framebuffer_allocator.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * framebuffer_allocator.h - FrameBuffer allocator
+ */
+#ifndef __LIBCAMERA_FRAMEBUFFER_ALLOCATOR_H__
+#define __LIBCAMERA_FRAMEBUFFER_ALLOCATOR_H__
+
+#include <map>
+#include <memory>
+#include <vector>
+
+namespace libcamera {
+
+class Camera;
+class FrameBuffer;
+class Stream;
+
+class FrameBufferAllocator
+{
+public:
+	static FrameBufferAllocator *create(std::shared_ptr<Camera> camera);
+
+	FrameBufferAllocator(const Camera &) = delete;
+	FrameBufferAllocator &operator=(const Camera &) = delete;
+
+	~FrameBufferAllocator();
+
+	int allocate(Stream *stream);
+	int free(Stream *stream);
+
+	bool allocated() const { return !buffers_.empty(); }
+	const std::vector<std::unique_ptr<FrameBuffer>> &buffers(Stream *stream) const;
+
+private:
+	FrameBufferAllocator(std::shared_ptr<Camera> camera);
+
+	std::shared_ptr<Camera> camera_;
+	std::map<Stream *, std::vector<std::unique_ptr<FrameBuffer>>> buffers_;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_FRAMEBUFFER_ALLOCATOR_H__ */
diff --git a/include/libcamera/meson.build b/include/libcamera/meson.build
index 543e6773..8db217bb 100644
--- a/include/libcamera/meson.build
+++ b/include/libcamera/meson.build
@@ -7,6 +7,7 @@ libcamera_api = files([
     'event_dispatcher.h',
     'event_notifier.h',
     'file_descriptor.h',
+    'framebuffer_allocator.h',
     'geometry.h',
     'logging.h',
     'object.h',
-- 
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