[libcamera-devel] [RFC PATCH 3/8] qcam: Convert to use MappedFrameBuffer

[Kieran Bingham]

Remove the local mapping code, and utilise the libcamera buffer map
helper class.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---

Working towards a more generic MappedBuffer base interface of the newly
introduced MappedFrameBuffer hits a snag that the viewfinder in qcam
already defines a type which conflicts.

Remove it by converting qcam to use the new MappedFrameBuffer types.


 src/qcam/main_window.cpp | 27 +++++++++++----------------
 src/qcam/main_window.h   |  2 +-
 src/qcam/viewfinder.cpp  |  4 ++--
 src/qcam/viewfinder.h    |  7 +------
 4 files changed, 15 insertions(+), 25 deletions(-)

diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
index 7bc13603774e..b25260ba7b28 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -446,10 +446,14 @@ int MainWindow::startCapture()
 
 		for (const std::unique_ptr<FrameBuffer> &buffer : allocator_->buffers(stream)) {
 			/* Map memory buffers and cache the mappings. */
-			const FrameBuffer::Plane &plane = buffer->planes().front();
-			void *memory = mmap(NULL, plane.length, PROT_READ, MAP_SHARED,
-					    plane.fd.fd(), 0);
-			mappedBuffers_[buffer.get()] = { memory, plane.length };
+			MappedFrameBuffer mapped(buffer.get(), PROT_READ);
+			if (!mapped.isValid()) {
+				qWarning() << "Failed to map buffer";
+				ret = mapped.error();
+				goto error;
+			}
+
+			mappedBuffers_.insert({buffer.get(), std::move(mapped)});
 
 			/* Store buffers on the free list. */
 			freeBuffers_[stream].enqueue(buffer.get());
@@ -512,12 +516,7 @@ error:
 	for (Request *request : requests)
 		delete request;
 
-	for (auto &iter : mappedBuffers_) {
-		const MappedBuffer &buffer = iter.second;
-		munmap(buffer.memory, buffer.size);
-	}
 	mappedBuffers_.clear();
-
 	freeBuffers_.clear();
 
 	delete allocator_;
@@ -548,10 +547,6 @@ void MainWindow::stopCapture()
 
 	camera_->requestCompleted.disconnect(this, &MainWindow::requestComplete);
 
-	for (auto &iter : mappedBuffers_) {
-		const MappedBuffer &buffer = iter.second;
-		munmap(buffer.memory, buffer.size);
-	}
 	mappedBuffers_.clear();
 
 	delete allocator_;
@@ -643,10 +638,10 @@ void MainWindow::processRaw(FrameBuffer *buffer, const ControlList &metadata)
 							"DNG Files (*.dng)");
 
 	if (!filename.isEmpty()) {
-		const MappedBuffer &mapped = mappedBuffers_[buffer];
+		const MappedFrameBuffer &mapped = mappedBuffers_.at(buffer);
 		DNGWriter::write(filename.toStdString().c_str(), camera_.get(),
 				 rawStream_->configuration(), metadata, buffer,
-				 mapped.memory);
+				 mapped.maps()[0].address);
 	}
 #endif
 
@@ -720,7 +715,7 @@ void MainWindow::processViewfinder(FrameBuffer *buffer)
 		<< "fps:" << Qt::fixed << qSetRealNumberPrecision(2) << fps;
 
 	/* Render the frame on the viewfinder. */
-	viewfinder_->render(buffer, &mappedBuffers_[buffer]);
+	viewfinder_->render(buffer, &mappedBuffers_.at(buffer));
 }
 
 void MainWindow::queueRequest(FrameBuffer *buffer)
diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h
index 4606fe487ad4..ddf51ca01111 100644
--- a/src/qcam/main_window.h
+++ b/src/qcam/main_window.h
@@ -119,7 +119,7 @@ private:
 	FrameBufferAllocator *allocator_;
 
 	std::unique_ptr<CameraConfiguration> config_;
-	std::map<FrameBuffer *, MappedBuffer> mappedBuffers_;
+	std::map<FrameBuffer *, MappedFrameBuffer> mappedBuffers_;
 
 	/* Capture state, buffers queue and statistics */
 	bool isCapturing_;
diff --git a/src/qcam/viewfinder.cpp b/src/qcam/viewfinder.cpp
index dcf8a15d2df6..591d26eae87c 100644
--- a/src/qcam/viewfinder.cpp
+++ b/src/qcam/viewfinder.cpp
@@ -78,14 +78,14 @@ int ViewFinder::setFormat(const libcamera::PixelFormat &format,
 	return 0;
 }
 
-void ViewFinder::render(libcamera::FrameBuffer *buffer, MappedBuffer *map)
+void ViewFinder::render(libcamera::FrameBuffer *buffer, libcamera::MappedFrameBuffer *map)
 {
 	if (buffer->planes().size() != 1) {
 		qWarning() << "Multi-planar buffers are not supported";
 		return;
 	}
 
-	unsigned char *memory = static_cast<unsigned char *>(map->memory);
+	unsigned char *memory = static_cast<unsigned char *>(map->maps()[0].address);
 	size_t size = buffer->metadata().planes[0].bytesused;
 
 	{
diff --git a/src/qcam/viewfinder.h b/src/qcam/viewfinder.h
index 26a1320537d2..c4cc51f14dda 100644
--- a/src/qcam/viewfinder.h
+++ b/src/qcam/viewfinder.h
@@ -23,11 +23,6 @@
 
 class QImage;
 
-struct MappedBuffer {
-	void *memory;
-	size_t size;
-};
-
 class ViewFinder : public QWidget
 {
 	Q_OBJECT
@@ -39,7 +34,7 @@ public:
 	const QList<libcamera::PixelFormat> &nativeFormats() const;
 
 	int setFormat(const libcamera::PixelFormat &format, const QSize &size);
-	void render(libcamera::FrameBuffer *buffer, MappedBuffer *map);
+	void render(libcamera::FrameBuffer *buffer, libcamera::MappedFrameBuffer *map);
 	void stop();
 
 	QImage getCurrentImage();
-- 
2.25.1