tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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screenshot-utils.mjs (2182B)

      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 file,
      3 * You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 
      5 /**
      6 * List of helper functions for screenshot-based images.
      7 *
      8 * There are two kinds of images:
      9 * 1. Remote Image: This is the image from the main process and it refers to
     10 *    the image in the React props. This can either be an object with the `data`
     11 *    and `path` properties, if it is a blob, or a string, if it is a normal image.
     12 * 2. Local Image: This is the image object in the content process and it refers
     13 *    to the image *object* in the React component's state. All local image
     14 *    objects have the `url` property, and an additional property `path`, if they
     15 *    are blobs.
     16 */
     17 export const ScreenshotUtils = {
     18  isBlob(isLocal, image) {
     19    return !!(
     20      image &&
     21      image.path &&
     22      ((!isLocal && image.data) || (isLocal && image.url))
     23    );
     24  },
     25 
     26  // This should always be called with a remote image and not a local image.
     27  createLocalImageObject(remoteImage) {
     28    if (!remoteImage) {
     29      return null;
     30    }
     31    if (this.isBlob(false, remoteImage)) {
     32      return {
     33        url: globalThis.URL.createObjectURL(remoteImage.data),
     34        path: remoteImage.path,
     35      };
     36    }
     37    return { url: remoteImage };
     38  },
     39 
     40  // Revokes the object URL of the image if the local image is a blob.
     41  // This should always be called with a local image and not a remote image.
     42  maybeRevokeBlobObjectURL(localImage) {
     43    if (this.isBlob(true, localImage)) {
     44      globalThis.URL.revokeObjectURL(localImage.url);
     45    }
     46  },
     47 
     48  // Checks if remoteImage and localImage are the same.
     49  isRemoteImageLocal(localImage, remoteImage) {
     50    // Both remoteImage and localImage are present.
     51    if (remoteImage && localImage) {
     52      return this.isBlob(false, remoteImage)
     53        ? localImage.path === remoteImage.path
     54        : localImage.url === remoteImage;
     55    }
     56 
     57    // This will only handle the remaining three possible outcomes.
     58    // (i.e. everything except when both image and localImage are present)
     59    return !remoteImage && !localImage;
     60  },
     61 };