mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-08 04:27:37 +00:00
73 lines
2.1 KiB
C++
73 lines
2.1 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
* You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef GFXCOWSURFACEWRAPPER
|
|
#define GFXCOWSURFACEWRAPPER
|
|
|
|
#include "gfxASurface.h"
|
|
#include "nsISupportsImpl.h"
|
|
#include "nsAutoPtr.h"
|
|
|
|
class gfxImageSurface;
|
|
|
|
/**
|
|
* Provides a cross thread wrapper for a gfxImageSurface
|
|
* that has copy-on-write schemantics.
|
|
*
|
|
* Only the owner thread can write to the surface and aquire
|
|
* read locks.
|
|
*
|
|
* OMTC Usage:
|
|
* 1) Content creates a writable copy of this surface
|
|
* wrapper which be optimized to the same wrapper if there
|
|
* are no readers.
|
|
* 2) The surface is sent from content to the compositor once
|
|
* or potentially many time, each increasing a read lock.
|
|
* 3) When the compositor has processed the surface and uploaded
|
|
* the content it then releases the read lock.
|
|
*/
|
|
class gfxReusableSurfaceWrapper {
|
|
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(gfxReusableSurfaceWrapper);
|
|
public:
|
|
/**
|
|
* Pass the gfxASurface to the wrapper.
|
|
* The wrapper should hold the only strong reference
|
|
* to the surface and its memebers.
|
|
*/
|
|
gfxReusableSurfaceWrapper(gfxImageSurface* aSurface);
|
|
|
|
~gfxReusableSurfaceWrapper();
|
|
|
|
const unsigned char* GetReadOnlyData() const {
|
|
NS_ABORT_IF_FALSE(mReadCount > 0, "Should have read lock");
|
|
return mSurfaceData;
|
|
}
|
|
|
|
const gfxASurface::gfxImageFormat& Format() { return mFormat; }
|
|
|
|
/**
|
|
* Get a writable copy of the image.
|
|
* If necessary this will copy the wrapper. If there are no contention
|
|
* the same wrapper will be returned.
|
|
*/
|
|
gfxReusableSurfaceWrapper* GetWritable(gfxImageSurface** aSurface);
|
|
|
|
/**
|
|
* A read only lock count is recorded, any attempts to
|
|
* call GetWritable() while this count is positive will
|
|
* create a new surface/wrapper pair.
|
|
*/
|
|
void ReadLock();
|
|
void ReadUnlock();
|
|
|
|
private:
|
|
NS_DECL_OWNINGTHREAD
|
|
nsRefPtr<gfxImageSurface> mSurface;
|
|
const gfxASurface::gfxImageFormat mFormat;
|
|
const unsigned char* mSurfaceData;
|
|
PRInt32 mReadCount;
|
|
};
|
|
|
|
#endif // GFXCOWSURFACEWRAPPER
|