pdf.js/src/core/document.js
Jonas Jenwald e9b7996f2f Actually compare the cropBox and mediaBox correctly in the Page.view getter
The current code will only consider the `cropBox` and `mediaBox` as equal when they both point to the *same* underlying Array. In the case where a PDF file actually specifies both boxes independently, with the exact same values in each, the comparison will currently fail and lead to an unneeded intersection computation.
2019-08-07 17:15:57 +02:00

686 lines
21 KiB
JavaScript

/* Copyright 2012 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* eslint no-var: error */
import {
assert, bytesToString, FormatError, info, isArrayBuffer, isArrayEqual, isBool,
isNum, isSpace, isString, OPS, shadow, stringToBytes, stringToPDFString, Util,
warn
} from '../shared/util';
import { Catalog, ObjectLoader, XRef } from './obj';
import { Dict, isDict, isName, isStream, Ref } from './primitives';
import {
getInheritableProperty, MissingDataException, XRefEntryException,
XRefParseException
} from './core_utils';
import { NullStream, Stream, StreamsSequenceStream } from './stream';
import { AnnotationFactory } from './annotation';
import { calculateMD5 } from './crypto';
import { Linearization } from './parser';
import { OperatorList } from './operator_list';
import { PartialEvaluator } from './evaluator';
import { PDFFunctionFactory } from './function';
const DEFAULT_USER_UNIT = 1.0;
const LETTER_SIZE_MEDIABOX = [0, 0, 612, 792];
function isAnnotationRenderable(annotation, intent) {
return (intent === 'display' && annotation.viewable) ||
(intent === 'print' && annotation.printable);
}
class Page {
constructor({ pdfManager, xref, pageIndex, pageDict, ref, fontCache,
builtInCMapCache, pdfFunctionFactory, }) {
this.pdfManager = pdfManager;
this.pageIndex = pageIndex;
this.pageDict = pageDict;
this.xref = xref;
this.ref = ref;
this.fontCache = fontCache;
this.builtInCMapCache = builtInCMapCache;
this.pdfFunctionFactory = pdfFunctionFactory;
this.evaluatorOptions = pdfManager.evaluatorOptions;
this.resourcesPromise = null;
const idCounters = {
obj: 0,
};
this.idFactory = {
createObjId() {
return `p${pageIndex}_${++idCounters.obj}`;
},
getDocId() {
return `g_${pdfManager.docId}`;
},
};
}
/**
* @private
*/
_getInheritableProperty(key, getArray = false) {
const value = getInheritableProperty({ dict: this.pageDict, key, getArray,
stopWhenFound: false, });
if (!Array.isArray(value)) {
return value;
}
if (value.length === 1 || !isDict(value[0])) {
return value[0];
}
return Dict.merge(this.xref, value);
}
get content() {
return this.pageDict.get('Contents');
}
get resources() {
// For robustness: The spec states that a \Resources entry has to be
// present, but can be empty. Some documents still omit it; in this case
// we return an empty dictionary.
return shadow(this, 'resources',
this._getInheritableProperty('Resources') || Dict.empty);
}
get mediaBox() {
const mediaBox = this._getInheritableProperty('MediaBox',
/* getArray = */ true);
// Reset invalid media box to letter size.
if (!Array.isArray(mediaBox) || mediaBox.length !== 4) {
return shadow(this, 'mediaBox', LETTER_SIZE_MEDIABOX);
}
return shadow(this, 'mediaBox', mediaBox);
}
get cropBox() {
const cropBox = this._getInheritableProperty('CropBox',
/* getArray = */ true);
// Reset invalid crop box to media box.
if (!Array.isArray(cropBox) || cropBox.length !== 4) {
return shadow(this, 'cropBox', this.mediaBox);
}
return shadow(this, 'cropBox', cropBox);
}
get userUnit() {
let obj = this.pageDict.get('UserUnit');
if (!isNum(obj) || obj <= 0) {
obj = DEFAULT_USER_UNIT;
}
return shadow(this, 'userUnit', obj);
}
get view() {
// From the spec, 6th ed., p.963:
// "The crop, bleed, trim, and art boxes should not ordinarily
// extend beyond the boundaries of the media box. If they do, they are
// effectively reduced to their intersection with the media box."
const { cropBox, mediaBox, } = this;
if (cropBox === mediaBox || isArrayEqual(cropBox, mediaBox)) {
return shadow(this, 'view', mediaBox);
}
const intersection = Util.intersect(cropBox, mediaBox);
return shadow(this, 'view', intersection || mediaBox);
}
get rotate() {
let rotate = this._getInheritableProperty('Rotate') || 0;
// Normalize rotation so it's a multiple of 90 and between 0 and 270.
if (rotate % 90 !== 0) {
rotate = 0;
} else if (rotate >= 360) {
rotate = rotate % 360;
} else if (rotate < 0) {
// The spec doesn't cover negatives. Assume it's counterclockwise
// rotation. The following is the other implementation of modulo.
rotate = ((rotate % 360) + 360) % 360;
}
return shadow(this, 'rotate', rotate);
}
getContentStream() {
const content = this.content;
let stream;
if (Array.isArray(content)) {
// Fetching the individual streams from the array.
const xref = this.xref;
const streams = [];
for (const stream of content) {
streams.push(xref.fetchIfRef(stream));
}
stream = new StreamsSequenceStream(streams);
} else if (isStream(content)) {
stream = content;
} else {
// Replace non-existent page content with empty content.
stream = new NullStream();
}
return stream;
}
loadResources(keys) {
if (!this.resourcesPromise) {
// TODO: add async `_getInheritableProperty` and remove this.
this.resourcesPromise = this.pdfManager.ensure(this, 'resources');
}
return this.resourcesPromise.then(() => {
const objectLoader = new ObjectLoader(this.resources, keys, this.xref);
return objectLoader.load();
});
}
getOperatorList({ handler, task, intent, renderInteractiveForms, }) {
const contentStreamPromise = this.pdfManager.ensure(this,
'getContentStream');
const resourcesPromise = this.loadResources([
'ExtGState',
'ColorSpace',
'Pattern',
'Shading',
'XObject',
'Font',
]);
const partialEvaluator = new PartialEvaluator({
xref: this.xref,
handler,
pageIndex: this.pageIndex,
idFactory: this.idFactory,
fontCache: this.fontCache,
builtInCMapCache: this.builtInCMapCache,
options: this.evaluatorOptions,
pdfFunctionFactory: this.pdfFunctionFactory,
});
const dataPromises = Promise.all([contentStreamPromise, resourcesPromise]);
const pageListPromise = dataPromises.then(([contentStream]) => {
const opList = new OperatorList(intent, handler, this.pageIndex);
handler.send('StartRenderPage', {
transparency: partialEvaluator.hasBlendModes(this.resources),
pageIndex: this.pageIndex,
intent,
});
return partialEvaluator.getOperatorList({
stream: contentStream,
task,
resources: this.resources,
operatorList: opList,
}).then(function() {
return opList;
});
});
// Fetch the page's annotations and add their operator lists to the
// page's operator list to render them.
return Promise.all([pageListPromise, this._parsedAnnotations]).then(
function([pageOpList, annotations]) {
if (annotations.length === 0) {
pageOpList.flush(true);
return pageOpList;
}
// Collect the operator list promises for the annotations. Each promise
// is resolved with the complete operator list for a single annotation.
const opListPromises = [];
for (const annotation of annotations) {
if (isAnnotationRenderable(annotation, intent)) {
opListPromises.push(annotation.getOperatorList(
partialEvaluator, task, renderInteractiveForms));
}
}
return Promise.all(opListPromises).then(function(opLists) {
pageOpList.addOp(OPS.beginAnnotations, []);
for (const opList of opLists) {
pageOpList.addOpList(opList);
}
pageOpList.addOp(OPS.endAnnotations, []);
pageOpList.flush(true);
return pageOpList;
});
});
}
extractTextContent({ handler, task, normalizeWhitespace, sink,
combineTextItems, }) {
const contentStreamPromise = this.pdfManager.ensure(this,
'getContentStream');
const resourcesPromise = this.loadResources([
'ExtGState',
'XObject',
'Font',
]);
const dataPromises = Promise.all([contentStreamPromise, resourcesPromise]);
return dataPromises.then(([contentStream]) => {
const partialEvaluator = new PartialEvaluator({
xref: this.xref,
handler,
pageIndex: this.pageIndex,
idFactory: this.idFactory,
fontCache: this.fontCache,
builtInCMapCache: this.builtInCMapCache,
options: this.evaluatorOptions,
pdfFunctionFactory: this.pdfFunctionFactory,
});
return partialEvaluator.getTextContent({
stream: contentStream,
task,
resources: this.resources,
normalizeWhitespace,
combineTextItems,
sink,
});
});
}
getAnnotationsData(intent) {
return this._parsedAnnotations.then(function(annotations) {
const annotationsData = [];
for (let i = 0, ii = annotations.length; i < ii; i++) {
if (!intent || isAnnotationRenderable(annotations[i], intent)) {
annotationsData.push(annotations[i].data);
}
}
return annotationsData;
});
}
get annotations() {
return shadow(this, 'annotations',
this._getInheritableProperty('Annots') || []);
}
get _parsedAnnotations() {
const parsedAnnotations =
this.pdfManager.ensure(this, 'annotations').then(() => {
const annotationRefs = this.annotations;
const annotationPromises = [];
for (let i = 0, ii = annotationRefs.length; i < ii; i++) {
annotationPromises.push(AnnotationFactory.create(
this.xref, annotationRefs[i], this.pdfManager, this.idFactory));
}
return Promise.all(annotationPromises).then(function(annotations) {
return annotations.filter(function isDefined(annotation) {
return !!annotation;
});
}, function(reason) {
warn(`_parsedAnnotations: "${reason}".`);
return [];
});
});
return shadow(this, '_parsedAnnotations', parsedAnnotations);
}
}
const FINGERPRINT_FIRST_BYTES = 1024;
const EMPTY_FINGERPRINT = '\x00\x00\x00\x00\x00\x00\x00' +
'\x00\x00\x00\x00\x00\x00\x00\x00\x00';
function find(stream, needle, limit, backwards = false) {
assert(limit > 0, 'The "limit" must be a positive integer.');
const str = bytesToString(stream.peekBytes(limit));
const index = backwards ? str.lastIndexOf(needle) : str.indexOf(needle);
if (index === -1) {
return false;
}
stream.pos += index;
return true;
}
/**
* The `PDFDocument` class holds all the data of the PDF file. There exists
* one `PDFDocument` object on the main thread and one object for each worker.
* If no worker support is enabled, two `PDFDocument` objects are created on
* the main thread.
*/
class PDFDocument {
constructor(pdfManager, arg) {
let stream;
if (isStream(arg)) {
stream = arg;
} else if (isArrayBuffer(arg)) {
stream = new Stream(arg);
} else {
throw new Error('PDFDocument: Unknown argument type');
}
if (stream.length <= 0) {
throw new Error('PDFDocument: Stream must have data');
}
this.pdfManager = pdfManager;
this.stream = stream;
this.xref = new XRef(stream, pdfManager);
this.pdfFunctionFactory = new PDFFunctionFactory({
xref: this.xref,
isEvalSupported: pdfManager.evaluatorOptions.isEvalSupported,
});
this._pagePromises = [];
}
parse(recoveryMode) {
this.setup(recoveryMode);
const version = this.catalog.catDict.get('Version');
if (isName(version)) {
this.pdfFormatVersion = version.name;
}
// Check if AcroForms are present in the document.
try {
this.acroForm = this.catalog.catDict.get('AcroForm');
if (this.acroForm) {
this.xfa = this.acroForm.get('XFA');
const fields = this.acroForm.get('Fields');
if ((!Array.isArray(fields) || fields.length === 0) && !this.xfa) {
this.acroForm = null; // No fields and no XFA, so it's not a form.
}
}
} catch (ex) {
if (ex instanceof MissingDataException) {
throw ex;
}
info('Cannot fetch AcroForm entry; assuming no AcroForms are present');
this.acroForm = null;
}
// Check if a Collection dictionary is present in the document.
try {
const collection = this.catalog.catDict.get('Collection');
if (isDict(collection) && collection.getKeys().length > 0) {
this.collection = collection;
}
} catch (ex) {
if (ex instanceof MissingDataException) {
throw ex;
}
info('Cannot fetch Collection dictionary.');
}
}
get linearization() {
let linearization = null;
try {
linearization = Linearization.create(this.stream);
} catch (err) {
if (err instanceof MissingDataException) {
throw err;
}
info(err);
}
return shadow(this, 'linearization', linearization);
}
get startXRef() {
const stream = this.stream;
let startXRef = 0;
if (this.linearization) {
// Find the end of the first object.
stream.reset();
if (find(stream, 'endobj', 1024)) {
startXRef = stream.pos + 6;
}
} else {
// Find `startxref` by checking backwards from the end of the file.
const step = 1024;
const startXRefLength = 'startxref'.length;
let found = false, pos = stream.end;
while (!found && pos > 0) {
pos -= step - startXRefLength;
if (pos < 0) {
pos = 0;
}
stream.pos = pos;
found = find(stream, 'startxref', step, true);
}
if (found) {
stream.skip(9);
let ch;
do {
ch = stream.getByte();
} while (isSpace(ch));
let str = '';
while (ch >= 0x20 && ch <= 0x39) { // < '9'
str += String.fromCharCode(ch);
ch = stream.getByte();
}
startXRef = parseInt(str, 10);
if (isNaN(startXRef)) {
startXRef = 0;
}
}
}
return shadow(this, 'startXRef', startXRef);
}
// Find the header, get the PDF format version and setup the
// stream to start from the header.
checkHeader() {
const stream = this.stream;
stream.reset();
if (!find(stream, '%PDF-', 1024)) {
// May not be a PDF file, but don't throw an error and let
// parsing continue.
return;
}
stream.moveStart();
// Read the PDF format version.
const MAX_PDF_VERSION_LENGTH = 12;
let version = '', ch;
while ((ch = stream.getByte()) > 0x20) { // Space
if (version.length >= MAX_PDF_VERSION_LENGTH) {
break;
}
version += String.fromCharCode(ch);
}
if (!this.pdfFormatVersion) {
// Remove the "%PDF-" prefix.
this.pdfFormatVersion = version.substring(5);
}
}
parseStartXRef() {
this.xref.setStartXRef(this.startXRef);
}
setup(recoveryMode) {
this.xref.parse(recoveryMode);
this.catalog = new Catalog(this.pdfManager, this.xref);
}
get numPages() {
const linearization = this.linearization;
const num = linearization ? linearization.numPages : this.catalog.numPages;
return shadow(this, 'numPages', num);
}
get documentInfo() {
const DocumentInfoValidators = {
Title: isString,
Author: isString,
Subject: isString,
Keywords: isString,
Creator: isString,
Producer: isString,
CreationDate: isString,
ModDate: isString,
Trapped: isName,
};
const docInfo = {
PDFFormatVersion: this.pdfFormatVersion,
IsLinearized: !!this.linearization,
IsAcroFormPresent: !!this.acroForm,
IsXFAPresent: !!this.xfa,
IsCollectionPresent: !!this.collection,
};
let infoDict;
try {
infoDict = this.xref.trailer.get('Info');
} catch (err) {
if (err instanceof MissingDataException) {
throw err;
}
info('The document information dictionary is invalid.');
}
if (isDict(infoDict)) {
// Fill the document info with valid entries from the specification,
// as well as any existing well-formed custom entries.
for (const key of infoDict.getKeys()) {
const value = infoDict.get(key);
if (DocumentInfoValidators[key]) {
// Make sure the (standard) value conforms to the specification.
if (DocumentInfoValidators[key](value)) {
docInfo[key] = (typeof value !== 'string' ?
value : stringToPDFString(value));
} else {
info(`Bad value in document info for "${key}".`);
}
} else if (typeof key === 'string') {
// For custom values, only accept white-listed types to prevent
// errors that would occur when trying to send non-serializable
// objects to the main-thread (for example `Dict` or `Stream`).
let customValue;
if (isString(value)) {
customValue = stringToPDFString(value);
} else if (isName(value) || isNum(value) || isBool(value)) {
customValue = value;
} else {
info(`Unsupported value in document info for (custom) "${key}".`);
continue;
}
if (!docInfo['Custom']) {
docInfo['Custom'] = Object.create(null);
}
docInfo['Custom'][key] = customValue;
}
}
}
return shadow(this, 'documentInfo', docInfo);
}
get fingerprint() {
let hash;
const idArray = this.xref.trailer.get('ID');
if (Array.isArray(idArray) && idArray[0] && isString(idArray[0]) &&
idArray[0] !== EMPTY_FINGERPRINT) {
hash = stringToBytes(idArray[0]);
} else {
hash = calculateMD5(this.stream.getByteRange(0, FINGERPRINT_FIRST_BYTES),
0, FINGERPRINT_FIRST_BYTES);
}
const fingerprintBuf = [];
for (let i = 0, ii = hash.length; i < ii; i++) {
const hex = hash[i].toString(16);
fingerprintBuf.push(hex.padStart(2, '0'));
}
return shadow(this, 'fingerprint', fingerprintBuf.join(''));
}
_getLinearizationPage(pageIndex) {
const { catalog, linearization, } = this;
assert(linearization && linearization.pageFirst === pageIndex);
const ref = Ref.get(linearization.objectNumberFirst, 0);
return this.xref.fetchAsync(ref).then((obj) => {
// Ensure that the object that was found is actually a Page dictionary.
if (isDict(obj, 'Page') ||
(isDict(obj) && !obj.has('Type') && obj.has('Contents'))) {
if (ref && !catalog.pageKidsCountCache.has(ref)) {
catalog.pageKidsCountCache.put(ref, 1); // Cache the Page reference.
}
return [obj, ref];
}
throw new FormatError('The Linearization dictionary doesn\'t point ' +
'to a valid Page dictionary.');
}).catch((reason) => {
info(reason);
return catalog.getPageDict(pageIndex);
});
}
getPage(pageIndex) {
if (this._pagePromises[pageIndex] !== undefined) {
return this._pagePromises[pageIndex];
}
const { catalog, linearization, } = this;
const promise = (linearization && linearization.pageFirst === pageIndex) ?
this._getLinearizationPage(pageIndex) : catalog.getPageDict(pageIndex);
return this._pagePromises[pageIndex] = promise.then(([pageDict, ref]) => {
return new Page({
pdfManager: this.pdfManager,
xref: this.xref,
pageIndex,
pageDict,
ref,
fontCache: catalog.fontCache,
builtInCMapCache: catalog.builtInCMapCache,
pdfFunctionFactory: this.pdfFunctionFactory,
});
});
}
checkFirstPage() {
return this.getPage(0).catch((reason) => {
if (reason instanceof XRefEntryException) {
// Clear out the various caches to ensure that we haven't stored any
// inconsistent and/or incorrect state, since that could easily break
// subsequent `this.getPage` calls.
this._pagePromises.length = 0;
this.cleanup();
throw new XRefParseException();
}
});
}
fontFallback(id, handler) {
return this.catalog.fontFallback(id, handler);
}
cleanup() {
return this.catalog.cleanup();
}
}
export {
Page,
PDFDocument,
};