tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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FetchImageHelper.h (2861B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 
      5 #ifndef DOM_MEDIA_MEDIACONTROL_FETCHIMAGEHELPER_H_
      6 #define DOM_MEDIA_MEDIACONTROL_FETCHIMAGEHELPER_H_
      7 
      8 #include "imgIContainer.h"
      9 #include "imgITools.h"
     10 #include "mozilla/MozPromise.h"
     11 #include "mozilla/dom/MediaSessionBinding.h"
     12 
     13 namespace mozilla::dom {
     14 /**
     15 * FetchImageHelper is used to fetch image data from MediaImage, and the fetched
     16 * image data would be used to show on the virtual control inferface. The URL of
     17 * MediaImage is defined by websites by using MediaSession API [1].
     18 *
     19 * By using `FetchImage()`, it would return a promise that would resolve with a
     20 * `imgIContainer`, then we can get the image data from the container.
     21 *
     22 * [1] https://w3c.github.io/mediasession/#dictdef-mediaimage
     23 */
     24 using ImagePromise = MozPromise<nsCOMPtr<imgIContainer>, bool,
     25                                /* IsExclusive = */ true>;
     26 class FetchImageHelper final {
     27 public:
     28  explicit FetchImageHelper(const MediaImage& aImage);
     29  ~FetchImageHelper();
     30 
     31  // Return a promise which would be resolved with the decoded image surface
     32  // when we finish fetching and decoding image data, and it would be rejected
     33  // when we fail to fecth the image.
     34  RefPtr<ImagePromise> FetchImage();
     35 
     36  // Stop fetching and decoding image and reject the image promise. If we have
     37  // not started yet fetching image, then nothing would happen.
     38  void AbortFetchingImage();
     39 
     40  // Return true if we're fecthing image.
     41  bool IsFetchingImage() const;
     42 
     43 private:
     44  /**
     45   * ImageFetchListener is used to listen the notification of finishing fetching
     46   * image data (via `OnImageReady()`) and finishing decoding image data (via
     47   * `Notify()`).
     48   */
     49  class ImageFetchListener final : public imgIContainerCallback {
     50   public:
     51    NS_DECL_ISUPPORTS
     52    ImageFetchListener() = default;
     53 
     54    // Start an async channel to load the image, and return error if the channel
     55    // opens failed. It would use `aHelper::HandleFetchSuccess/Fail()` to notify
     56    // the result asynchronously.
     57    nsresult FetchDecodedImageFromURI(nsIURI* aURI, FetchImageHelper* aHelper);
     58    void Clear();
     59    bool IsFetchingImage() const;
     60 
     61    // Method of imgIContainerCallback
     62    NS_IMETHOD OnImageReady(imgIContainer* aImage, nsresult aStatus) override;
     63 
     64   private:
     65    ~ImageFetchListener();
     66 
     67    FetchImageHelper* MOZ_NON_OWNING_REF mHelper = nullptr;
     68    nsCOMPtr<nsIChannel> mChannel;
     69  };
     70 
     71  void ClearListenerIfNeeded();
     72  void HandleFetchSuccess(imgIContainer* aImage);
     73  void HandleFetchFail();
     74 
     75  nsString mSrc;
     76  MozPromiseHolder<ImagePromise> mPromise;
     77  RefPtr<ImageFetchListener> mListener;
     78 };
     79 
     80 }  // namespace mozilla::dom
     81 
     82 #endif  // DOM_MEDIA_MEDIACONTROL_FETCHIMAGEHELPER_H_