[Pkg-javascript-commits] [pdf.js] 17/109: [PATCH] Add fallback for font loading when eval disabled
David Prévot
taffit at moszumanska.debian.org
Fri Sep 25 03:04:13 UTC 2015
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taffit pushed a commit to branch master
in repository pdf.js.
commit 341c5e9d1faa5f9fe6bc006cda14f5ab6244b897
Author: Mike Skalnik <mike.skalnik at gmail.com>
Date: Wed Jun 24 15:29:36 2015 -0500
[PATCH] Add fallback for font loading when eval disabled
In some cases, such as in use with a CSP header, constructing a function with a
string of javascript is not allowed. However, compiling the various commands
that need to be done on the canvas element is faster than interpreting them.
This patch changes the font renderer to instead emit commands that are compiled
by the font loader. If, during compilation, we receive an EvalError, we instead
interpret them.
---
src/core/font_renderer.js | 60 ++++++++++++++++++++++------------------------
src/display/api.js | 8 +++++++
src/display/font_loader.js | 49 ++++++++++++++++++++++++++++++++++---
3 files changed, 83 insertions(+), 34 deletions(-)
diff --git a/src/core/font_renderer.js b/src/core/font_renderer.js
index 7609645..d71051f 100644
--- a/src/core/font_renderer.js
+++ b/src/core/font_renderer.js
@@ -134,16 +134,15 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
return 0;
}
- function compileGlyf(code, js, font) {
+ function compileGlyf(code, cmds, font) {
function moveTo(x, y) {
- js.push('c.moveTo(' + x + ',' + y + ');');
+ cmds.push({cmd: 'moveTo', args: [x, y]});
}
function lineTo(x, y) {
- js.push('c.lineTo(' + x + ',' + y + ');');
+ cmds.push({cmd: 'lineTo', args: [x, y]});
}
function quadraticCurveTo(xa, ya, x, y) {
- js.push('c.quadraticCurveTo(' + xa + ',' + ya + ',' +
- x + ',' + y + ');');
+ cmds.push({cmd: 'quadraticCurveTo', args: [xa, ya, x, y]});
}
var i = 0;
@@ -189,11 +188,11 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
}
var subglyph = font.glyphs[glyphIndex];
if (subglyph) {
- js.push('c.save();');
- js.push('c.transform(' + scaleX + ',' + scale01 + ',' +
- scale10 + ',' + scaleY + ',' + x + ',' + y + ');');
- compileGlyf(subglyph, js, font);
- js.push('c.restore();');
+ cmds.push({cmd: 'save'});
+ cmds.push({cmd: 'transform',
+ args: [scaleX, scale01, scale10, scaleY, x, y]});
+ compileGlyf(subglyph, cmds, font);
+ cmds.push({cmd: 'restore'});
}
} while ((flags & 0x20));
} else {
@@ -289,20 +288,19 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
}
}
- function compileCharString(code, js, font) {
+ function compileCharString(code, cmds, font) {
var stack = [];
var x = 0, y = 0;
var stems = 0;
function moveTo(x, y) {
- js.push('c.moveTo(' + x + ',' + y + ');');
+ cmds.push({cmd: 'moveTo', args: [x, y]});
}
function lineTo(x, y) {
- js.push('c.lineTo(' + x + ',' + y + ');');
+ cmds.push({cmd: 'lineTo', args: [x, y]});
}
function bezierCurveTo(x1, y1, x2, y2, x, y) {
- js.push('c.bezierCurveTo(' + x1 + ',' + y1 + ',' + x2 + ',' + y2 + ',' +
- x + ',' + y + ');');
+ cmds.push({cmd: 'bezierCurveTo', args: [x1, y1, x2, y2, x, y]});
}
function parse(code) {
@@ -431,16 +429,16 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
var bchar = stack.pop();
y = stack.pop();
x = stack.pop();
- js.push('c.save();');
- js.push('c.translate('+ x + ',' + y + ');');
+ cmds.push({cmd: 'save'});
+ cmds.push({cmd: 'translate', args: [x, y]});
var gid = lookupCmap(font.cmap, String.fromCharCode(
font.glyphNameMap[Encodings.StandardEncoding[achar]]));
- compileCharString(font.glyphs[gid], js, font);
- js.push('c.restore();');
+ compileCharString(font.glyphs[gid], cmds, font);
+ cmds.push({cmd: 'restore'});
gid = lookupCmap(font.cmap, String.fromCharCode(
font.glyphNameMap[Encodings.StandardEncoding[bchar]]));
- compileCharString(font.glyphs[gid], js, font);
+ compileCharString(font.glyphs[gid], cmds, font);
}
return;
case 18: // hstemhm
@@ -609,16 +607,16 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
return noop;
}
- var js = [];
- js.push('c.save();');
- js.push('c.transform(' + this.fontMatrix.join(',') + ');');
- js.push('c.scale(size, -size);');
+ var cmds = [];
+ cmds.push({cmd: 'save'});
+ cmds.push({cmd: 'transform', args: this.fontMatrix.slice()});
+ cmds.push({cmd: 'scale', args: ['size', '-size']});
- this.compileGlyphImpl(code, js);
+ this.compileGlyphImpl(code, cmds);
- js.push('c.restore();');
+ cmds.push({cmd: 'restore'});
- return js.join('\n');
+ return cmds;
},
compileGlyphImpl: function () {
@@ -642,8 +640,8 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
}
Util.inherit(TrueTypeCompiled, CompiledFont, {
- compileGlyphImpl: function (code, js) {
- compileGlyf(code, js, this);
+ compileGlyphImpl: function (code, cmds) {
+ compileGlyf(code, cmds, this);
}
});
@@ -664,8 +662,8 @@ var FontRendererFactory = (function FontRendererFactoryClosure() {
}
Util.inherit(Type2Compiled, CompiledFont, {
- compileGlyphImpl: function (code, js) {
- compileCharString(code, js, this);
+ compileGlyphImpl: function (code, cmds) {
+ compileCharString(code, cmds, this);
}
});
diff --git a/src/display/api.js b/src/display/api.js
index 7919cb4..bf2c77a 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -178,6 +178,14 @@ PDFJS.openExternalLinksInNewWindow = (
false : PDFJS.openExternalLinksInNewWindow);
/**
+ * Determines if we can eval strings as JS. Primarily used to improve
+ * performance for font rendering.
+ * @var {boolean}
+ */
+PDFJS.isEvalSupported = (PDFJS.isEvalSupported === undefined ?
+ true : PDFJS.isEvalSupported);
+
+/**
* Document initialization / loading parameters object.
*
* @typedef {Object} DocumentInitParameters
diff --git a/src/display/font_loader.js b/src/display/font_loader.js
index 76b4f24..b7aceaa 100644
--- a/src/display/font_loader.js
+++ b/src/display/font_loader.js
@@ -77,6 +77,18 @@ var FontLoader = {
));
},
+ get isEvalSupported() {
+ var evalSupport = false;
+ if (PDFJS.isEvalSupported) {
+ try {
+ /* jshint evil: true */
+ new Function('');
+ evalSupport = true;
+ } catch (e) {}
+ }
+ return shadow(this, 'isEvalSupported', evalSupport);
+ },
+
loadTestFontId: 0,
loadingContext: {
@@ -365,9 +377,40 @@ var FontFaceObject = (function FontFaceObjectClosure() {
getPathGenerator: function FontLoader_getPathGenerator(objs, character) {
if (!(character in this.compiledGlyphs)) {
- var js = objs.get(this.loadedName + '_path_' + character);
- /*jshint -W054 */
- this.compiledGlyphs[character] = new Function('c', 'size', js);
+ var cmds = objs.get(this.loadedName + '_path_' + character);
+ var current, i, len;
+
+ // If we can, compile cmds into JS for MAXIMUM SPEED
+ if (FontLoader.isEvalSupported) {
+ var args, js = '';
+ for (i = 0, len = cmds.length; i < len; i++) {
+ current = cmds[i];
+
+ if (current.args !== undefined) {
+ args = current.args.join(',');
+ } else {
+ args = '';
+ }
+
+ js += 'c.' + current.cmd + '(' + args + ');\n';
+ }
+ /* jshint -W054 */
+ this.compiledGlyphs[character] = new Function('c', 'size', js);
+ } else {
+ // But fall back on using Function.prototype.apply() if we're
+ // blocked from using eval() for whatever reason (like CSP policies)
+ this.compiledGlyphs[character] = function(c, size) {
+ for (i = 0, len = cmds.length; i < len; i++) {
+ current = cmds[i];
+
+ if (current.cmd === 'scale') {
+ current.args = [size, -size];
+ }
+
+ c[current.cmd].apply(c, current.args);
+ }
+ };
+ }
}
return this.compiledGlyphs[character];
}
--
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