mirror of
https://github.com/classilla/tenfourfox.git
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141 lines
4.1 KiB
JavaScript
141 lines
4.1 KiB
JavaScript
waitForExplicitFinish();
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var pageSource =
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'<html><body>' +
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'<img id="testImg" src="' + TESTROOT + 'big.png">' +
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'</body></html>';
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var oldDiscardingPref, oldTab, newTab;
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var prefBranch = Cc["@mozilla.org/preferences-service;1"]
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.getService(Ci.nsIPrefService)
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.getBranch('image.mem.');
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var gWaitingForDiscard = false;
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var gScriptedObserver;
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var gClonedRequest;
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function ImageObserver(decodeCallback, discardCallback) {
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this.decodeComplete = function onDecodeComplete(aRequest) {
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decodeCallback();
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}
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this.discard = function onDiscard(request)
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{
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if (!gWaitingForDiscard) {
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return;
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}
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this.synchronous = false;
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discardCallback();
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}
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this.synchronous = true;
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}
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function currentRequest() {
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let img = gBrowser.getBrowserForTab(newTab).contentWindow
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.document.getElementById('testImg');
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img.QueryInterface(Ci.nsIImageLoadingContent);
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return img.getRequest(Ci.nsIImageLoadingContent.CURRENT_REQUEST);
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}
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function isImgDecoded() {
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let request = currentRequest();
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return request.imageStatus & Ci.imgIRequest.STATUS_DECODE_COMPLETE ? true : false;
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}
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// Ensure that the image is decoded by drawing it to a canvas.
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function forceDecodeImg() {
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let doc = gBrowser.getBrowserForTab(newTab).contentWindow.document;
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let img = doc.getElementById('testImg');
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let canvas = doc.createElement('canvas');
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let ctx = canvas.getContext('2d');
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ctx.drawImage(img, 0, 0);
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}
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function runAfterAsyncEvents(aCallback) {
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function handlePostMessage(aEvent) {
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if (aEvent.data == 'next') {
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window.removeEventListener('message', handlePostMessage, false);
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aCallback();
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}
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}
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window.addEventListener('message', handlePostMessage, false);
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// We'll receive the 'message' event after everything else that's currently in
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// the event queue (which is a stronger guarantee than setTimeout, because
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// setTimeout events may be coalesced). This lets us ensure that we run
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// aCallback *after* any asynchronous events are delivered.
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window.postMessage('next', '*');
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}
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function test() {
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// Enable the discarding pref.
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oldDiscardingPref = prefBranch.getBoolPref('discardable');
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prefBranch.setBoolPref('discardable', true);
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// Create and focus a new tab.
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oldTab = gBrowser.selectedTab;
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newTab = gBrowser.addTab('data:text/html,' + pageSource);
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gBrowser.selectedTab = newTab;
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// Run step2 after the tab loads.
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gBrowser.getBrowserForTab(newTab)
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.addEventListener("pageshow", step2);
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}
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function step2() {
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// Create the image observer.
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var observer =
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new ImageObserver(() => runAfterAsyncEvents(step3), // DECODE_COMPLETE
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() => runAfterAsyncEvents(step5)); // DISCARD
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gScriptedObserver = Cc["@mozilla.org/image/tools;1"]
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.getService(Ci.imgITools)
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.createScriptedObserver(observer);
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// Clone the current imgIRequest with our new observer.
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var request = currentRequest();
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gClonedRequest = request.clone(gScriptedObserver);
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// Check that the image is decoded.
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forceDecodeImg();
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// The DECODE_COMPLETE notification is delivered asynchronously. ImageObserver will
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// eventually call step3.
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}
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function step3() {
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ok(isImgDecoded(), 'Image should initially be decoded.');
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// Focus the old tab, then fire a memory-pressure notification. This should
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// cause the decoded image in the new tab to be discarded.
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gBrowser.selectedTab = oldTab;
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// Allow time to process the tab change.
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runAfterAsyncEvents(step4);
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}
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function step4() {
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gWaitingForDiscard = true;
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var os = Cc["@mozilla.org/observer-service;1"]
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.getService(Ci.nsIObserverService);
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os.notifyObservers(null, 'memory-pressure', 'heap-minimize');
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// The DISCARD notification is delivered asynchronously. ImageObserver will
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// eventually call step5. (Or else, sadly, the test will time out.)
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}
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function step5() {
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ok(true, 'Image should be discarded.');
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// And we're done.
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gBrowser.removeTab(newTab);
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prefBranch.setBoolPref('discardable', oldDiscardingPref);
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gClonedRequest.cancelAndForgetObserver(0);
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finish();
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}
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