pdfjs-dist
Version:
Generic build of Mozilla's PDF.js library.
456 lines (455 loc) • 14.2 kB
JavaScript
/**
* @licstart The following is the entire license notice for the
* JavaScript code in this page
*
* Copyright 2022 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.
*
* @licend The above is the entire license notice for the
* JavaScript code in this page
*/
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.ChunkedStreamManager = exports.ChunkedStream = void 0;
var _util = require("../shared/util.js");
var _core_utils = require("./core_utils.js");
var _stream = require("./stream.js");
class ChunkedStream extends _stream.Stream {
constructor(length, chunkSize, manager) {
super(new Uint8Array(length), 0, length, null);
this.chunkSize = chunkSize;
this._loadedChunks = new Set();
this.numChunks = Math.ceil(length / chunkSize);
this.manager = manager;
this.progressiveDataLength = 0;
this.lastSuccessfulEnsureByteChunk = -1;
}
getMissingChunks() {
const chunks = [];
for (let chunk = 0, n = this.numChunks; chunk < n; ++chunk) {
if (!this._loadedChunks.has(chunk)) {
chunks.push(chunk);
}
}
return chunks;
}
get numChunksLoaded() {
return this._loadedChunks.size;
}
get isDataLoaded() {
return this.numChunksLoaded === this.numChunks;
}
onReceiveData(begin, chunk) {
const chunkSize = this.chunkSize;
if (begin % chunkSize !== 0) {
throw new Error(`Bad begin offset: ${begin}`);
}
const end = begin + chunk.byteLength;
if (end % chunkSize !== 0 && end !== this.bytes.length) {
throw new Error(`Bad end offset: ${end}`);
}
this.bytes.set(new Uint8Array(chunk), begin);
const beginChunk = Math.floor(begin / chunkSize);
const endChunk = Math.floor((end - 1) / chunkSize) + 1;
for (let curChunk = beginChunk; curChunk < endChunk; ++curChunk) {
this._loadedChunks.add(curChunk);
}
}
onReceiveProgressiveData(data) {
let position = this.progressiveDataLength;
const beginChunk = Math.floor(position / this.chunkSize);
this.bytes.set(new Uint8Array(data), position);
position += data.byteLength;
this.progressiveDataLength = position;
const endChunk = position >= this.end ? this.numChunks : Math.floor(position / this.chunkSize);
for (let curChunk = beginChunk; curChunk < endChunk; ++curChunk) {
this._loadedChunks.add(curChunk);
}
}
ensureByte(pos) {
if (pos < this.progressiveDataLength) {
return;
}
const chunk = Math.floor(pos / this.chunkSize);
if (chunk > this.numChunks) {
return;
}
if (chunk === this.lastSuccessfulEnsureByteChunk) {
return;
}
if (!this._loadedChunks.has(chunk)) {
throw new _core_utils.MissingDataException(pos, pos + 1);
}
this.lastSuccessfulEnsureByteChunk = chunk;
}
ensureRange(begin, end) {
if (begin >= end) {
return;
}
if (end <= this.progressiveDataLength) {
return;
}
const beginChunk = Math.floor(begin / this.chunkSize);
if (beginChunk > this.numChunks) {
return;
}
const endChunk = Math.min(Math.floor((end - 1) / this.chunkSize) + 1, this.numChunks);
for (let chunk = beginChunk; chunk < endChunk; ++chunk) {
if (!this._loadedChunks.has(chunk)) {
throw new _core_utils.MissingDataException(begin, end);
}
}
}
nextEmptyChunk(beginChunk) {
const numChunks = this.numChunks;
for (let i = 0; i < numChunks; ++i) {
const chunk = (beginChunk + i) % numChunks;
if (!this._loadedChunks.has(chunk)) {
return chunk;
}
}
return null;
}
hasChunk(chunk) {
return this._loadedChunks.has(chunk);
}
getByte() {
const pos = this.pos;
if (pos >= this.end) {
return -1;
}
if (pos >= this.progressiveDataLength) {
this.ensureByte(pos);
}
return this.bytes[this.pos++];
}
getBytes(length) {
const bytes = this.bytes;
const pos = this.pos;
const strEnd = this.end;
if (!length) {
if (strEnd > this.progressiveDataLength) {
this.ensureRange(pos, strEnd);
}
return bytes.subarray(pos, strEnd);
}
let end = pos + length;
if (end > strEnd) {
end = strEnd;
}
if (end > this.progressiveDataLength) {
this.ensureRange(pos, end);
}
this.pos = end;
return bytes.subarray(pos, end);
}
getByteRange(begin, end) {
if (begin < 0) {
begin = 0;
}
if (end > this.end) {
end = this.end;
}
if (end > this.progressiveDataLength) {
this.ensureRange(begin, end);
}
return this.bytes.subarray(begin, end);
}
makeSubStream(start, length, dict = null) {
if (length) {
if (start + length > this.progressiveDataLength) {
this.ensureRange(start, start + length);
}
} else {
if (start >= this.progressiveDataLength) {
this.ensureByte(start);
}
}
function ChunkedStreamSubstream() {}
ChunkedStreamSubstream.prototype = Object.create(this);
ChunkedStreamSubstream.prototype.getMissingChunks = function () {
const chunkSize = this.chunkSize;
const beginChunk = Math.floor(this.start / chunkSize);
const endChunk = Math.floor((this.end - 1) / chunkSize) + 1;
const missingChunks = [];
for (let chunk = beginChunk; chunk < endChunk; ++chunk) {
if (!this._loadedChunks.has(chunk)) {
missingChunks.push(chunk);
}
}
return missingChunks;
};
Object.defineProperty(ChunkedStreamSubstream.prototype, "isDataLoaded", {
get() {
if (this.numChunksLoaded === this.numChunks) {
return true;
}
return this.getMissingChunks().length === 0;
},
configurable: true
});
const subStream = new ChunkedStreamSubstream();
subStream.pos = subStream.start = start;
subStream.end = start + length || this.end;
subStream.dict = dict;
return subStream;
}
getBaseStreams() {
return [this];
}
}
exports.ChunkedStream = ChunkedStream;
class ChunkedStreamManager {
constructor(pdfNetworkStream, args) {
this.length = args.length;
this.chunkSize = args.rangeChunkSize;
this.stream = new ChunkedStream(this.length, this.chunkSize, this);
this.pdfNetworkStream = pdfNetworkStream;
this.disableAutoFetch = args.disableAutoFetch;
this.msgHandler = args.msgHandler;
this.currRequestId = 0;
this._chunksNeededByRequest = new Map();
this._requestsByChunk = new Map();
this._promisesByRequest = new Map();
this.progressiveDataLength = 0;
this.aborted = false;
this._loadedStreamCapability = (0, _util.createPromiseCapability)();
}
sendRequest(begin, end) {
const rangeReader = this.pdfNetworkStream.getRangeReader(begin, end);
if (!rangeReader.isStreamingSupported) {
rangeReader.onProgress = this.onProgress.bind(this);
}
let chunks = [],
loaded = 0;
return new Promise((resolve, reject) => {
const readChunk = chunk => {
try {
if (!chunk.done) {
const data = chunk.value;
chunks.push(data);
loaded += (0, _util.arrayByteLength)(data);
if (rangeReader.isStreamingSupported) {
this.onProgress({
loaded
});
}
rangeReader.read().then(readChunk, reject);
return;
}
const chunkData = (0, _util.arraysToBytes)(chunks);
chunks = null;
resolve(chunkData);
} catch (e) {
reject(e);
}
};
rangeReader.read().then(readChunk, reject);
}).then(data => {
if (this.aborted) {
return;
}
this.onReceiveData({
chunk: data,
begin
});
});
}
requestAllChunks(noFetch = false) {
if (!noFetch) {
const missingChunks = this.stream.getMissingChunks();
this._requestChunks(missingChunks);
}
return this._loadedStreamCapability.promise;
}
_requestChunks(chunks) {
const requestId = this.currRequestId++;
const chunksNeeded = new Set();
this._chunksNeededByRequest.set(requestId, chunksNeeded);
for (const chunk of chunks) {
if (!this.stream.hasChunk(chunk)) {
chunksNeeded.add(chunk);
}
}
if (chunksNeeded.size === 0) {
return Promise.resolve();
}
const capability = (0, _util.createPromiseCapability)();
this._promisesByRequest.set(requestId, capability);
const chunksToRequest = [];
for (const chunk of chunksNeeded) {
let requestIds = this._requestsByChunk.get(chunk);
if (!requestIds) {
requestIds = [];
this._requestsByChunk.set(chunk, requestIds);
chunksToRequest.push(chunk);
}
requestIds.push(requestId);
}
if (chunksToRequest.length > 0) {
const groupedChunksToRequest = this.groupChunks(chunksToRequest);
for (const groupedChunk of groupedChunksToRequest) {
const begin = groupedChunk.beginChunk * this.chunkSize;
const end = Math.min(groupedChunk.endChunk * this.chunkSize, this.length);
this.sendRequest(begin, end).catch(capability.reject);
}
}
return capability.promise.catch(reason => {
if (this.aborted) {
return;
}
throw reason;
});
}
getStream() {
return this.stream;
}
requestRange(begin, end) {
end = Math.min(end, this.length);
const beginChunk = this.getBeginChunk(begin);
const endChunk = this.getEndChunk(end);
const chunks = [];
for (let chunk = beginChunk; chunk < endChunk; ++chunk) {
chunks.push(chunk);
}
return this._requestChunks(chunks);
}
requestRanges(ranges = []) {
const chunksToRequest = [];
for (const range of ranges) {
const beginChunk = this.getBeginChunk(range.begin);
const endChunk = this.getEndChunk(range.end);
for (let chunk = beginChunk; chunk < endChunk; ++chunk) {
if (!chunksToRequest.includes(chunk)) {
chunksToRequest.push(chunk);
}
}
}
chunksToRequest.sort(function (a, b) {
return a - b;
});
return this._requestChunks(chunksToRequest);
}
groupChunks(chunks) {
const groupedChunks = [];
let beginChunk = -1;
let prevChunk = -1;
for (let i = 0, ii = chunks.length; i < ii; ++i) {
const chunk = chunks[i];
if (beginChunk < 0) {
beginChunk = chunk;
}
if (prevChunk >= 0 && prevChunk + 1 !== chunk) {
groupedChunks.push({
beginChunk,
endChunk: prevChunk + 1
});
beginChunk = chunk;
}
if (i + 1 === chunks.length) {
groupedChunks.push({
beginChunk,
endChunk: chunk + 1
});
}
prevChunk = chunk;
}
return groupedChunks;
}
onProgress(args) {
this.msgHandler.send("DocProgress", {
loaded: this.stream.numChunksLoaded * this.chunkSize + args.loaded,
total: this.length
});
}
onReceiveData(args) {
const chunk = args.chunk;
const isProgressive = args.begin === undefined;
const begin = isProgressive ? this.progressiveDataLength : args.begin;
const end = begin + chunk.byteLength;
const beginChunk = Math.floor(begin / this.chunkSize);
const endChunk = end < this.length ? Math.floor(end / this.chunkSize) : Math.ceil(end / this.chunkSize);
if (isProgressive) {
this.stream.onReceiveProgressiveData(chunk);
this.progressiveDataLength = end;
} else {
this.stream.onReceiveData(begin, chunk);
}
if (this.stream.isDataLoaded) {
this._loadedStreamCapability.resolve(this.stream);
}
const loadedRequests = [];
for (let curChunk = beginChunk; curChunk < endChunk; ++curChunk) {
const requestIds = this._requestsByChunk.get(curChunk);
if (!requestIds) {
continue;
}
this._requestsByChunk.delete(curChunk);
for (const requestId of requestIds) {
const chunksNeeded = this._chunksNeededByRequest.get(requestId);
if (chunksNeeded.has(curChunk)) {
chunksNeeded.delete(curChunk);
}
if (chunksNeeded.size > 0) {
continue;
}
loadedRequests.push(requestId);
}
}
if (!this.disableAutoFetch && this._requestsByChunk.size === 0) {
let nextEmptyChunk;
if (this.stream.numChunksLoaded === 1) {
const lastChunk = this.stream.numChunks - 1;
if (!this.stream.hasChunk(lastChunk)) {
nextEmptyChunk = lastChunk;
}
} else {
nextEmptyChunk = this.stream.nextEmptyChunk(endChunk);
}
if (Number.isInteger(nextEmptyChunk)) {
this._requestChunks([nextEmptyChunk]);
}
}
for (const requestId of loadedRequests) {
const capability = this._promisesByRequest.get(requestId);
this._promisesByRequest.delete(requestId);
capability.resolve();
}
this.msgHandler.send("DocProgress", {
loaded: this.stream.numChunksLoaded * this.chunkSize,
total: this.length
});
}
onError(err) {
this._loadedStreamCapability.reject(err);
}
getBeginChunk(begin) {
return Math.floor(begin / this.chunkSize);
}
getEndChunk(end) {
return Math.floor((end - 1) / this.chunkSize) + 1;
}
abort(reason) {
this.aborted = true;
if (this.pdfNetworkStream) {
this.pdfNetworkStream.cancelAllRequests(reason);
}
for (const capability of this._promisesByRequest.values()) {
capability.reject(reason);
}
}
}
exports.ChunkedStreamManager = ChunkedStreamManager;