tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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imgutils.js (4038B)

      1 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
      2 // Helper file for shared image functionality
      3 //
      4 // Note that this is use by tests elsewhere in the source tree. When in doubt,
      5 // check mxr before removing or changing functionality.
      6 
      7 // Helper function to clear both the content and chrome image caches
      8 function clearAllImageCaches() {
      9  var tools = SpecialPowers.Cc["@mozilla.org/image/tools;1"].getService(
     10    SpecialPowers.Ci.imgITools
     11  );
     12  var imageCache = tools.getImgCacheForDocument(window.document);
     13  imageCache.clearCache(); // no parameter=all
     14 }
     15 
     16 // Helper function to clear the image cache of content images
     17 function clearImageCache() {
     18  var tools = SpecialPowers.Cc["@mozilla.org/image/tools;1"].getService(
     19    SpecialPowers.Ci.imgITools
     20  );
     21  var imageCache = tools.getImgCacheForDocument(window.document);
     22  imageCache.clearCache(false); // true=chrome, false=content
     23 }
     24 
     25 // Helper function to determine if the frame is decoded for a given image id
     26 function isFrameDecoded(id) {
     27  return !!(
     28    getImageStatus(id) & SpecialPowers.Ci.imgIRequest.STATUS_FRAME_COMPLETE
     29  );
     30 }
     31 
     32 // Helper function to determine if the image is loaded for a given image id
     33 function isImageLoaded(id) {
     34  return !!(
     35    getImageStatus(id) & SpecialPowers.Ci.imgIRequest.STATUS_LOAD_COMPLETE
     36  );
     37 }
     38 
     39 // Helper function to get the status flags of an image
     40 function getImageStatus(id) {
     41  // Get the image
     42  var img = SpecialPowers.wrap(document.getElementById(id));
     43 
     44  // Get the request
     45  var request = img.getRequest(
     46    SpecialPowers.Ci.nsIImageLoadingContent.CURRENT_REQUEST
     47  );
     48 
     49  // Return the status
     50  return request.imageStatus;
     51 }
     52 
     53 // Forces a synchronous decode of an image by drawing it to a canvas. Only
     54 // really meaningful if the image is fully loaded first
     55 function forceDecode(id) {
     56  // Get the image
     57  var img = document.getElementById(id);
     58 
     59  // Make a new canvas
     60  var canvas = document.createElement("canvas");
     61 
     62  // Draw the image to the canvas. This forces a synchronous decode
     63  var ctx = canvas.getContext("2d");
     64  ctx.drawImage(img, 0, 0);
     65 }
     66 
     67 // Functions to facilitate getting/setting various image-related prefs
     68 //
     69 // If you change a pref in a mochitest, Don't forget to reset it to its
     70 // original value!
     71 //
     72 // Null indicates no pref set
     73 
     74 const DISCARD_ENABLED_PREF = {
     75  name: "discardable",
     76  branch: "image.mem.",
     77  type: "bool",
     78 };
     79 const DECODEONDRAW_ENABLED_PREF = {
     80  name: "decodeondraw",
     81  branch: "image.mem.",
     82  type: "bool",
     83 };
     84 const DISCARD_TIMEOUT_PREF = {
     85  name: "min_discard_timeout_ms",
     86  branch: "image.mem.",
     87  type: "int",
     88 };
     89 
     90 function setImagePref(pref, val) {
     91  var prefService = SpecialPowers.Services.prefs;
     92  var branch = prefService.getBranch(pref.branch);
     93  if (val != null) {
     94    switch (pref.type) {
     95      case "bool":
     96        branch.setBoolPref(pref.name, val);
     97        break;
     98      case "int":
     99        branch.setIntPref(pref.name, val);
    100        break;
    101      default:
    102        throw new Error("Unknown pref type");
    103    }
    104  } else if (branch.prefHasUserValue(pref.name)) {
    105    branch.clearUserPref(pref.name);
    106  }
    107 }
    108 
    109 function getImagePref(pref) {
    110  var prefService = SpecialPowers.Services.prefs;
    111  var branch = prefService.getBranch(pref.branch);
    112  if (branch.prefHasUserValue(pref.name)) {
    113    switch (pref.type) {
    114      case "bool":
    115        return branch.getBoolPref(pref.name);
    116      case "int":
    117        return branch.getIntPref(pref.name);
    118      default:
    119        throw new Error("Unknown pref type");
    120    }
    121  } else {
    122    return null;
    123  }
    124 }
    125 
    126 // JS implementation of imgIScriptedNotificationObserver with stubs for all of its methods.
    127 function ImageDecoderObserverStub() {
    128  this.sizeAvailable = function sizeAvailable() {};
    129  this.frameComplete = function frameComplete() {};
    130  this.decodeComplete = function decodeComplete() {};
    131  this.loadComplete = function loadComplete() {};
    132  this.frameUpdate = function frameUpdate() {};
    133  this.discard = function discard() {};
    134  this.isAnimated = function isAnimated() {};
    135  this.hasTransparency = function hasTransparency() {};
    136 }