add assert helpers, small cleanup
This commit is contained in:
Chris Jones
parent
8f8b302b23
commit
d7f3c31d9d
69
pdf.js
69
pdf.js
@ -1,5 +1,6 @@
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/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- /
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/* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
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function warn(msg) {
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if (console && console.log)
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console.log(msg);
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@ -11,6 +12,18 @@ function error(msg) {
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throw new Error(msg);
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}
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function assert(cond, msg) {
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if (!cond)
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error(msg);
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}
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// In a well-formed PDF, |cond| holds. If it doesn't, subsequent
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// behavior is undefined.
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function assertWellFormed(cond, msg) {
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if (!cond)
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error("Malformed PDF: "+ msg);
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}
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function shadow(obj, prop, value) {
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Object.defineProperty(obj, prop, { value: value, enumerable: true });
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return value;
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@ -1811,8 +1824,8 @@ var Page = (function() {
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var contents = xref.fetchIfRef(this.contents);
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var resources = xref.fetchIfRef(this.resources);
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var mediaBox = xref.fetchIfRef(this.mediaBox);
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if (!IsStream(contents) || !IsDict(resources))
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error("invalid page contents or resources");
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assertWellFormed(IsStream(contents) && IsDict(resources),
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"invalid page contents or resources");
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gfx.beginDrawing({ x: mediaBox[0], y: mediaBox[1],
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width: mediaBox[2] - mediaBox[0],
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height: mediaBox[3] - mediaBox[1] });
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@ -1829,45 +1842,42 @@ var Catalog = (function() {
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function constructor(xref) {
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this.xref = xref;
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var obj = xref.getCatalogObj();
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if (!IsDict(obj))
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error("catalog object is not a dictionary");
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assertWellFormed(IsDict(obj), "catalog object is not a dictionary");
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this.catDict = obj;
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}
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constructor.prototype = {
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get toplevelPagesDict() {
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var obj = this.catDict.get("Pages");
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if (!IsRef(obj))
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error("invalid top-level pages reference");
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assertWellFormed(IsRef(obj), "invalid top-level pages reference");
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var obj = this.xref.fetch(obj);
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if (!IsDict(obj))
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error("invalid top-level pages dictionary");
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assertWellFormed(IsDict(obj), "invalid top-level pages dictionary");
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// shadow the prototype getter
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return shadow(this, "toplevelPagesDict", obj);
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},
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get numPages() {
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obj = this.toplevelPagesDict.get("Count");
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if (!IsInt(obj))
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error("page count in top level pages object is not an integer");
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assertWellFormed(IsInt(obj),
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"page count in top level pages object is not an integer");
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// shadow the prototype getter
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return shadow(this, "num", obj);
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},
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traverseKids: function(pagesDict) {
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var pageCache = this.pageCache;
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var kids = pagesDict.get("Kids");
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if (!IsArray(kids))
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error("page dictionary kids object is not an array");
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assertWellFormed(IsArray(kids),
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"page dictionary kids object is not an array");
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for (var i = 0; i < kids.length; ++i) {
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var kid = kids[i];
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if (!IsRef(kid))
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error("page dictionary kid is not a reference");
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assertWellFormed(IsRef(kid),
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"page dictionary kid is not a reference");
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var obj = this.xref.fetch(kid);
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if (IsDict(obj, "Page") || (IsDict(obj) && !obj.has("Kids"))) {
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pageCache.push(new Page(this.xref, pageCache.length, obj));
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} else if (IsDict(obj)) { // must be a child page dictionary
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} else { // must be a child page dictionary
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assertWellFormed(IsDict(obj),
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"page dictionary kid reference points to wrong type of object");
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this.traverseKids(obj);
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} else {
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error("page dictionary kid reference points to wrong type of object");
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}
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}
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},
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@ -1988,9 +1998,7 @@ var PDFDoc = (function() {
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},
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getPage: function(n) {
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var linearization = this.linearization;
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if (linearization) {
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error("linearized page access not implemented");
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}
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assert(!linearization, "linearized page access not implemented");
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return this.catalog.getPage(n);
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}
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};
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@ -2112,15 +2120,13 @@ var CanvasGraphics = (function() {
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if (IsCmd(obj)) {
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var cmd = obj.cmd;
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var fn = map[cmd];
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if (fn)
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// TODO figure out how to type-check vararg functions
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fn.apply(this, args);
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else
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error("Unknown command '" + cmd + "'");
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assertWellFormed(fn, "Unknown command '" + cmd + "'");
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// TODO figure out how to type-check vararg functions
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fn.apply(this, args);
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args.length = 0;
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} else {
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if (args.length > 33)
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error("Too many arguments '" + cmd + "'");
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assertWellFormed(args.length <= 33, "Too many arguments");
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args.push(obj);
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}
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}
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@ -2256,10 +2262,10 @@ var CanvasGraphics = (function() {
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var e = arr[i];
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if (IsNum(e)) {
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this.current.curX -= e * 0.001 * this.current.fontSize;
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} else if (IsString(e)) {
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this.showText(e);
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} else {
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error("Unexpected element in TJ array");
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assertWellFormed(IsString(e),
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"TJ array element isn't string or num");
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this.showText(e);
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}
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}
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},
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@ -2306,8 +2312,7 @@ var CanvasGraphics = (function() {
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if (!xobj)
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return;
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xobj = this.xref.fetchIfRef(xobj);
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if (!IsStream(xobj))
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error("XObject should be a stream");
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assertWellFormed(IsStream(xobj), "XObject should be a stream");
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this.interpret(new Parser(new Lexer(xobj), false),
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this.xref, xobj.dict.get("Resources"));
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