From 683f64d54f7724d75ad919ed00db6306c557d90e Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Sun, 11 Dec 2011 16:56:45 -0800
Subject: [PATCH] Use promises to track completion of decoding.
---
src/evaluator.js | 7 ++--
src/image.js | 86 ++++++++++++++++++++++++++----------------------
src/util.js | 28 +++++++++++++++-
3 files changed, 75 insertions(+), 46 deletions(-)
diff --git a/src/evaluator.js b/src/evaluator.js
index cb46d1b3b..8b860175e 100644
--- a/src/evaluator.js
+++ b/src/evaluator.js
@@ -219,10 +219,8 @@ var PartialEvaluator = (function partialEvaluator() {
}
fn = 'paintImageXObject';
- var imageObj = new PDFImage(xref, resources, image, inline, handler);
- imageObj.ready((function() {
- return function(data) {
+ PDFImage.buildImage(function(imageObj) {
var imgData = {
width: w,
height: h,
@@ -231,8 +229,7 @@ var PartialEvaluator = (function partialEvaluator() {
var pixels = imgData.data;
imageObj.fillRgbaBuffer(pixels, imageObj.decode);
handler.send('obj', [objId, 'Image', imgData]);
- };
- })(objId));
+ }, handler, xref, resources, image, inline);
}
uniquePrefix = uniquePrefix || '';
diff --git a/src/image.js b/src/image.js
index 7b9b12c18..ac00a1cb4 100644
--- a/src/image.js
+++ b/src/image.js
@@ -4,11 +4,28 @@
'use strict';
var PDFImage = (function pdfImage() {
- function constructor(xref, res, image, inline, handler) {
+ /**
+ * Decode the image in the main thread if it supported. Resovles the promise
+ * when the image data is ready.
+ */
+ function handleImageData(handler, xref, res, image, promise) {
+ if (image instanceof JpegStream && image.isNative) {
+ // For natively supported jpegs send them to the main thread for decoding.
+ var dict = image.dict;
+ var colorSpace = dict.get('ColorSpace', 'CS');
+ colorSpace = ColorSpace.parse(colorSpace, xref, res);
+ var numComps = colorSpace.numComps;
+ handler.send('jpeg_decode', [image.getIR(), numComps], function(message) {
+ var data = message.data;
+ var stream = new Stream(data, 0, data.length, image.dict);
+ promise.resolve(stream);
+ });
+ } else {
+ promise.resolve(image);
+ }
+ }
+ function constructor(xref, res, image, inline, smask) {
this.image = image;
- this.imageReady = true;
- this.smaskReady = true;
- this.callbacks = [];
if (image.getParams) {
// JPX/JPEG2000 streams directly contain bits per component
@@ -55,31 +72,37 @@ var PDFImage = (function pdfImage() {
this.decode = dict.get('Decode', 'D');
var mask = xref.fetchIfRef(dict.get('Mask'));
- var smask = xref.fetchIfRef(dict.get('SMask'));
if (mask) {
TODO('masked images');
} else if (smask) {
- this.smaskReady = false;
- this.smask = new PDFImage(xref, res, smask, false, handler);
- this.smask.ready(function() {
- this.smaskReady = true;
- if (this.isReady())
- this.fireReady();
- }.bind(this));
- }
-
- if (image instanceof JpegStream && image.isNative) {
- this.imageReady = false;
- handler.send('jpeg_decode', [image.getIR(), this.numComps], function(message) {
- var data = message.data;
- this.image = new Stream(data, 0, data.length);
- this.imageReady = true;
- if (this.isReady())
- this.fireReady();
- }.bind(this));
+ this.smask = new PDFImage(xref, res, smask, false);
}
}
+ /**
+ * Handles processing of image data and calls the callback with an argument
+ * of a PDFImage when the image is ready to be used.
+ */
+ constructor.buildImage = function buildImage(callback, handler, xref, res,
+ image, inline) {
+ var promise = new Promise();
+ var smaskPromise = new Promise();
+ var promises = [promise, smaskPromise];
+ // The image data and smask data may not be ready yet, wait till both are
+ // resolved.
+ Promise.all(promises).then(function(results) {
+ var image = new PDFImage(xref, res, results[0], inline, results[1]);
+ callback(image);
+ });
+
+ handleImageData(handler, xref, res, image, promise);
+
+ var smask = xref.fetchIfRef(image.dict.get('SMask'));
+ if (smask)
+ handleImageData(handler, xref, res, smask, smaskPromise);
+ else
+ smaskPromise.resolve(null);
+ };
constructor.prototype = {
getComponents: function getComponents(buffer, decodeMap) {
@@ -151,8 +174,6 @@ var PDFImage = (function pdfImage() {
var buf = new Uint8Array(width * height);
if (smask) {
- if (!smask.isReady())
- error('Soft mask is not ready.');
var sw = smask.width;
var sh = smask.height;
if (sw != this.width || sh != this.height)
@@ -234,23 +255,8 @@ var PDFImage = (function pdfImage() {
buffer[i] = comps[i];
},
getImageBytes: function getImageBytes(length) {
- if (!this.isReady())
- error('Image is not ready to be read.');
this.image.reset();
return this.image.getBytes(length);
- },
- isReady: function isReady() {
- return this.imageReady && this.smaskReady;
- },
- fireReady: function fireReady() {
- for (var i = 0; i < this.callbacks.length; ++i)
- this.callbacks[i]();
- this.callbacks = [];
- },
- ready: function ready(callback) {
- this.callbacks.push(callback);
- if (this.isReady())
- this.fireReady();
}
};
return constructor;
diff --git a/src/util.js b/src/util.js
index 4fb96f062..75cc87c6d 100644
--- a/src/util.js
+++ b/src/util.js
@@ -217,7 +217,33 @@ var Promise = (function promise() {
}
this.callbacks = [];
};
-
+ /**
+ * Builds a promise that is resolved when all the passed in promises are
+ * resolved.
+ * @param Array promises
+ * @return Promise
+ */
+ Promise.all = function(promises) {
+ var deferred = new Promise();
+ var unresolved = promises.length;
+ var results = [];
+ if (unresolved === 0) {
+ deferred.resolve(results);
+ return deferred;
+ }
+ for (var i = 0; i < unresolved; ++i) {
+ var promise = promises[i];
+ promise.then((function(i) {
+ return function(value) {
+ results[i] = value;
+ unresolved--;
+ if (unresolved === 0)
+ deferred.resolve(results);
+ };
+ })(i));
+ }
+ return deferred;
+ };
Promise.prototype = {
hasData: false,