Source code
Revision control
Copy as Markdown
Other Tools
/* 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
#ifndef DOM_MEDIA_MEDIACONTROL_FETCHIMAGEHELPER_H_
#define DOM_MEDIA_MEDIACONTROL_FETCHIMAGEHELPER_H_
#include "imgIContainer.h"
#include "imgITools.h"
#include "mozilla/dom/MediaSessionBinding.h"
#include "mozilla/MozPromise.h"
namespace mozilla::dom {
/**
* FetchImageHelper is used to fetch image data from MediaImage, and the fetched
* image data would be used to show on the virtual control inferface. The URL of
* MediaImage is defined by websites by using MediaSession API [1].
*
* By using `FetchImage()`, it would return a promise that would resolve with a
* `imgIContainer`, then we can get the image data from the container.
*
*/
using ImagePromise = MozPromise<nsCOMPtr<imgIContainer>, bool,
/* IsExclusive = */ true>;
class FetchImageHelper final {
public:
explicit FetchImageHelper(const MediaImage& aImage);
~FetchImageHelper();
// Return a promise which would be resolved with the decoded image surface
// when we finish fetching and decoding image data, and it would be rejected
// when we fail to fecth the image.
RefPtr<ImagePromise> FetchImage();
// Stop fetching and decoding image and reject the image promise. If we have
// not started yet fetching image, then nothing would happen.
void AbortFetchingImage();
// Return true if we're fecthing image.
bool IsFetchingImage() const;
private:
/**
* ImageFetchListener is used to listen the notification of finishing fetching
* image data (via `OnImageReady()`) and finishing decoding image data (via
* `Notify()`).
*/
class ImageFetchListener final : public imgIContainerCallback {
public:
NS_DECL_ISUPPORTS
ImageFetchListener() = default;
// Start an async channel to load the image, and return error if the channel
// opens failed. It would use `aHelper::HandleFetchSuccess/Fail()` to notify
// the result asynchronously.
nsresult FetchDecodedImageFromURI(nsIURI* aURI, FetchImageHelper* aHelper);
void Clear();
bool IsFetchingImage() const;
// Method of imgIContainerCallback
NS_IMETHOD OnImageReady(imgIContainer* aImage, nsresult aStatus) override;
private:
~ImageFetchListener();
FetchImageHelper* MOZ_NON_OWNING_REF mHelper = nullptr;
nsCOMPtr<nsIChannel> mChannel;
};
void ClearListenerIfNeeded();
void HandleFetchSuccess(imgIContainer* aImage);
void HandleFetchFail();
nsString mSrc;
MozPromiseHolder<ImagePromise> mPromise;
RefPtr<ImageFetchListener> mListener;
};
} // namespace mozilla::dom
#endif // DOM_MEDIA_MEDIACONTROL_FETCHIMAGEHELPER_H_