[libcamera-devel] [PATCH] qcam: Replace MappedBuffer with Span<uint8_t>
Jean-Michel Hautbois
jeanmichel.hautbois at ideasonboard.com
Wed Aug 18 07:29:36 CEST 2021
Hi Laurent,
Thank you for the patch.
On 18/08/2021 02:22, Laurent Pinchart wrote:
> The MappedBuffer structure is a custom container that binds a data
> pointer with a length. This is exactly what Span is. Use it instead.
>
Could you explain why it is better with a Span than with a buffer and
length ? As far as I can tell, it is only a matter of how it is declared
:-) ?
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
> src/qcam/main_window.cpp | 17 +++++++++--------
> src/qcam/main_window.h | 2 +-
> src/qcam/viewfinder.h | 9 +++------
> src/qcam/viewfinder_gl.cpp | 5 +++--
> src/qcam/viewfinder_gl.h | 2 +-
> src/qcam/viewfinder_qt.cpp | 5 +++--
> src/qcam/viewfinder_qt.h | 2 +-
> 7 files changed, 21 insertions(+), 21 deletions(-)
>
> diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
> index 39d034de6bb2..1adaae60d83b 100644
> --- a/src/qcam/main_window.cpp
> +++ b/src/qcam/main_window.cpp
> @@ -474,7 +474,8 @@ int MainWindow::startCapture()
> 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 };
> + mappedBuffers_[buffer.get()] = { static_cast<uint8_t *>(memory),
> + plane.length };
>
> /* Store buffers on the free list. */
> freeBuffers_[stream].enqueue(buffer.get());
> @@ -537,8 +538,8 @@ error:
> requests_.clear();
>
> for (auto &iter : mappedBuffers_) {
> - const MappedBuffer &buffer = iter.second;
> - munmap(buffer.memory, buffer.size);
> + const Span<uint8_t> &buffer = iter.second;
> + munmap(buffer.data(), buffer.size());
> }
> mappedBuffers_.clear();
>
> @@ -573,8 +574,8 @@ void MainWindow::stopCapture()
> camera_->requestCompleted.disconnect(this, &MainWindow::requestComplete);
>
> for (auto &iter : mappedBuffers_) {
> - const MappedBuffer &buffer = iter.second;
> - munmap(buffer.memory, buffer.size);
> + const Span<uint8_t> &buffer = iter.second;
> + munmap(buffer.data(), buffer.size());
> }
> mappedBuffers_.clear();
>
> @@ -673,10 +674,10 @@ void MainWindow::processRaw(FrameBuffer *buffer,
> "DNG Files (*.dng)");
>
> if (!filename.isEmpty()) {
> - const MappedBuffer &mapped = mappedBuffers_[buffer];
> + const Span<uint8_t> &mapped = mappedBuffers_[buffer];
> DNGWriter::write(filename.toStdString().c_str(), camera_.get(),
> rawStream_->configuration(), metadata, buffer,
> - mapped.memory);
> + mapped.data());
> }
> #endif
>
> @@ -753,7 +754,7 @@ 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_[buffer]);
> }
>
> void MainWindow::queueRequest(FrameBuffer *buffer)
> diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h
> index 85d56ce49abe..6788de8ddde9 100644
> --- a/src/qcam/main_window.h
> +++ b/src/qcam/main_window.h
> @@ -106,7 +106,7 @@ private:
> FrameBufferAllocator *allocator_;
>
> std::unique_ptr<CameraConfiguration> config_;
> - std::map<FrameBuffer *, MappedBuffer> mappedBuffers_;
> + std::map<FrameBuffer *, Span<uint8_t>> mappedBuffers_;
>
> /* Capture state, buffers queue and statistics */
> bool isCapturing_;
> diff --git a/src/qcam/viewfinder.h b/src/qcam/viewfinder.h
> index 46747c227d0c..42d40f1f33f0 100644
> --- a/src/qcam/viewfinder.h
> +++ b/src/qcam/viewfinder.h
> @@ -11,14 +11,11 @@
> #include <QList>
> #include <QSize>
>
> +#include <libcamera/base/span.h>
> +
> #include <libcamera/formats.h>
> #include <libcamera/framebuffer.h>
>
> -struct MappedBuffer {
> - void *memory;
> - size_t size;
> -};
> -
> class ViewFinder
> {
> public:
> @@ -27,7 +24,7 @@ public:
> virtual const QList<libcamera::PixelFormat> &nativeFormats() const = 0;
>
> virtual int setFormat(const libcamera::PixelFormat &format, const QSize &size) = 0;
> - virtual void render(libcamera::FrameBuffer *buffer, MappedBuffer *map) = 0;
> + virtual void render(libcamera::FrameBuffer *buffer, libcamera::Span<uint8_t> mem) = 0;
> virtual void stop() = 0;
>
> virtual QImage getCurrentImage() = 0;
> diff --git a/src/qcam/viewfinder_gl.cpp b/src/qcam/viewfinder_gl.cpp
> index add87db88207..40226601f9fd 100644
> --- a/src/qcam/viewfinder_gl.cpp
> +++ b/src/qcam/viewfinder_gl.cpp
> @@ -110,7 +110,8 @@ QImage ViewFinderGL::getCurrentImage()
> return grabFramebuffer();
> }
>
> -void ViewFinderGL::render(libcamera::FrameBuffer *buffer, MappedBuffer *map)
> +void ViewFinderGL::render(libcamera::FrameBuffer *buffer,
> + libcamera::Span<uint8_t> mem)
> {
> if (buffer->planes().size() != 1) {
> qWarning() << "Multi-planar buffers are not supported";
> @@ -120,7 +121,7 @@ void ViewFinderGL::render(libcamera::FrameBuffer *buffer, MappedBuffer *map)
> if (buffer_)
> renderComplete(buffer_);
>
> - data_ = static_cast<unsigned char *>(map->memory);
> + data_ = mem.data();
> /*
> * \todo Get the stride from the buffer instead of computing it naively
> */
> diff --git a/src/qcam/viewfinder_gl.h b/src/qcam/viewfinder_gl.h
> index 4a0f8ca58f29..3334549e0be4 100644
> --- a/src/qcam/viewfinder_gl.h
> +++ b/src/qcam/viewfinder_gl.h
> @@ -39,7 +39,7 @@ public:
> const QList<libcamera::PixelFormat> &nativeFormats() const override;
>
> int setFormat(const libcamera::PixelFormat &format, const QSize &size) override;
> - void render(libcamera::FrameBuffer *buffer, MappedBuffer *map) override;
> + void render(libcamera::FrameBuffer *buffer, libcamera::Span<uint8_t> mem) override;
> void stop() override;
>
> QImage getCurrentImage() override;
> diff --git a/src/qcam/viewfinder_qt.cpp b/src/qcam/viewfinder_qt.cpp
> index e436714c6bdb..efa1d412584b 100644
> --- a/src/qcam/viewfinder_qt.cpp
> +++ b/src/qcam/viewfinder_qt.cpp
> @@ -78,14 +78,15 @@ int ViewFinderQt::setFormat(const libcamera::PixelFormat &format,
> return 0;
> }
>
> -void ViewFinderQt::render(libcamera::FrameBuffer *buffer, MappedBuffer *map)
> +void ViewFinderQt::render(libcamera::FrameBuffer *buffer,
> + libcamera::Span<uint8_t> mem)
> {
> 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 = mem.data();
> size_t size = buffer->metadata().planes[0].bytesused;
>
> {
> diff --git a/src/qcam/viewfinder_qt.h b/src/qcam/viewfinder_qt.h
> index 501c72a70dec..1a569b9cee6e 100644
> --- a/src/qcam/viewfinder_qt.h
> +++ b/src/qcam/viewfinder_qt.h
> @@ -32,7 +32,7 @@ public:
> const QList<libcamera::PixelFormat> &nativeFormats() const override;
>
> int setFormat(const libcamera::PixelFormat &format, const QSize &size) override;
> - void render(libcamera::FrameBuffer *buffer, MappedBuffer *map) override;
> + void render(libcamera::FrameBuffer *buffer, libcamera::Span<uint8_t> mem) override;
> void stop() override;
>
> QImage getCurrentImage() override;
>
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