From 24f14d44cb7ebda981bcbb3e1cb83feab801bd24 Mon Sep 17 00:00:00 2001
From: Yury Delendik <ydelendik@mozilla.com>
Date: Mon, 12 Jun 2017 16:04:35 -0500
Subject: [PATCH] Preventing from using the same canvas for multiple render()
---
src/display/api.js | 20 +++++++++++++++++++-
test/unit/api_spec.js | 26 ++++++++++++++++++++++++++
2 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/src/display/api.js b/src/display/api.js
index fcde21d49..729b62764 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -901,7 +901,7 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
stats.time('Rendering');
internalRenderTask.initializeGraphics(transparency);
internalRenderTask.operatorListChanged();
- }, complete);
+ }).catch(complete);
return renderTask;
},
@@ -2103,6 +2103,7 @@ var RenderTask = (function RenderTaskClosure() {
* @ignore
*/
var InternalRenderTask = (function InternalRenderTaskClosure() {
+ let canvasInRendering = new WeakMap();
function InternalRenderTask(callback, params, objs, commonObjs, operatorList,
pageNumber, canvasFactory) {
@@ -2125,6 +2126,7 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
this._continueBound = this._continue.bind(this);
this._scheduleNextBound = this._scheduleNext.bind(this);
this._nextBound = this._next.bind(this);
+ this._canvas = params.canvasContext.canvas;
}
InternalRenderTask.prototype = {
@@ -2132,6 +2134,16 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
initializeGraphics:
function InternalRenderTask_initializeGraphics(transparency) {
+ if (this._canvas) {
+ if (canvasInRendering.has(this._canvas)) {
+ throw new Error(
+ 'Cannot use the same canvas during multiple render() operations. ' +
+ 'Use different canvas or ensure previous operations were ' +
+ 'cancelled or completed.');
+ }
+ canvasInRendering.set(this._canvas, this);
+ }
+
if (this.cancelled) {
return;
}
@@ -2163,6 +2175,9 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
cancel: function InternalRenderTask_cancel() {
this.running = false;
this.cancelled = true;
+ if (this._canvas) {
+ canvasInRendering.delete(this._canvas);
+ }
if ((typeof PDFJSDev !== 'undefined' && PDFJSDev.test('PDFJS_NEXT')) ||
getDefaultSetting('pdfjsNext')) {
@@ -2223,6 +2238,9 @@ var InternalRenderTask = (function InternalRenderTaskClosure() {
this.running = false;
if (this.operatorList.lastChunk) {
this.gfx.endDrawing();
+ if (this._canvas) {
+ canvasInRendering.delete(this._canvas);
+ }
this.callback();
}
}
diff --git a/test/unit/api_spec.js b/test/unit/api_spec.js
index f22988e76..d6d3d690c 100644
--- a/test/unit/api_spec.js
+++ b/test/unit/api_spec.js
@@ -1041,6 +1041,32 @@ describe('api', function() {
done();
});
});
+ it('multiple render() on the same canvas', function(done) {
+ if (isNodeJS()) {
+ pending('TODO: Support Canvas testing in Node.js.');
+ }
+ var viewport = page.getViewport(1);
+ var canvasAndCtx = CanvasFactory.create(viewport.width, viewport.height);
+
+ var renderTask1 = page.render({
+ canvasContext: canvasAndCtx.context,
+ viewport,
+ });
+ var renderTask2 = page.render({
+ canvasContext: canvasAndCtx.context,
+ viewport,
+ });
+
+ Promise.all([
+ renderTask1.promise,
+ renderTask2.promise.then(() => {
+ done.fail('shall fail rendering');
+ }, (reason) => {
+ /* it fails because we already using this canvas */
+ expect(/multiple render\(\)/.test(reason.message)).toEqual(true);
+ })
+ ]).then(done);
+ });
});
describe('Multiple PDFJS instances', function() {
if (isNodeJS()) {