pdfjs-dist/lib/display/network.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2021 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.PDFNetworkStream = void 0;

var _util = require("../shared/util.js");

var _network_utils = require("./network_utils.js");

;
const OK_RESPONSE = 200;
const PARTIAL_CONTENT_RESPONSE = 206;

function getArrayBuffer(xhr) {
  const data = xhr.response;

  if (typeof data !== "string") {
    return data;
  }

  const array = (0, _util.stringToBytes)(data);
  return array.buffer;
}

class NetworkManager {
  constructor(url, args = {}) {
    this.url = url;
    this.isHttp = /^https?:/i.test(url);
    this.httpHeaders = this.isHttp && args.httpHeaders || Object.create(null);
    this.withCredentials = args.withCredentials || false;

    this.getXhr = args.getXhr || function NetworkManager_getXhr() {
      return new XMLHttpRequest();
    };

    this.currXhrId = 0;
    this.pendingRequests = Object.create(null);
  }

  requestRange(begin, end, listeners) {
    const args = {
      begin,
      end
    };

    for (const prop in listeners) {
      args[prop] = listeners[prop];
    }

    return this.request(args);
  }

  requestFull(listeners) {
    return this.request(listeners);
  }

  request(args) {
    const xhr = this.getXhr();
    const xhrId = this.currXhrId++;
    const pendingRequest = this.pendingRequests[xhrId] = {
      xhr
    };
    xhr.open("GET", this.url);
    xhr.withCredentials = this.withCredentials;

    for (const property in this.httpHeaders) {
      const value = this.httpHeaders[property];

      if (typeof value === "undefined") {
        continue;
      }

      xhr.setRequestHeader(property, value);
    }

    if (this.isHttp && "begin" in args && "end" in args) {
      xhr.setRequestHeader("Range", `bytes=${args.begin}-${args.end - 1}`);
      pendingRequest.expectedStatus = PARTIAL_CONTENT_RESPONSE;
    } else {
      pendingRequest.expectedStatus = OK_RESPONSE;
    }

    xhr.responseType = "arraybuffer";

    if (args.onError) {
      xhr.onerror = function (evt) {
        args.onError(xhr.status);
      };
    }

    xhr.onreadystatechange = this.onStateChange.bind(this, xhrId);
    xhr.onprogress = this.onProgress.bind(this, xhrId);
    pendingRequest.onHeadersReceived = args.onHeadersReceived;
    pendingRequest.onDone = args.onDone;
    pendingRequest.onError = args.onError;
    pendingRequest.onProgress = args.onProgress;
    xhr.send(null);
    return xhrId;
  }

  onProgress(xhrId, evt) {
    const pendingRequest = this.pendingRequests[xhrId];

    if (!pendingRequest) {
      return;
    }

    pendingRequest.onProgress?.(evt);
  }

  onStateChange(xhrId, evt) {
    const pendingRequest = this.pendingRequests[xhrId];

    if (!pendingRequest) {
      return;
    }

    const xhr = pendingRequest.xhr;

    if (xhr.readyState >= 2 && pendingRequest.onHeadersReceived) {
      pendingRequest.onHeadersReceived();
      delete pendingRequest.onHeadersReceived;
    }

    if (xhr.readyState !== 4) {
      return;
    }

    if (!(xhrId in this.pendingRequests)) {
      return;
    }

    delete this.pendingRequests[xhrId];

    if (xhr.status === 0 && this.isHttp) {
      pendingRequest.onError?.(xhr.status);
      return;
    }

    const xhrStatus = xhr.status || OK_RESPONSE;
    const ok_response_on_range_request = xhrStatus === OK_RESPONSE && pendingRequest.expectedStatus === PARTIAL_CONTENT_RESPONSE;

    if (!ok_response_on_range_request && xhrStatus !== pendingRequest.expectedStatus) {
      pendingRequest.onError?.(xhr.status);
      return;
    }

    const chunk = getArrayBuffer(xhr);

    if (xhrStatus === PARTIAL_CONTENT_RESPONSE) {
      const rangeHeader = xhr.getResponseHeader("Content-Range");
      const matches = /bytes (\d+)-(\d+)\/(\d+)/.exec(rangeHeader);
      pendingRequest.onDone({
        begin: parseInt(matches[1], 10),
        chunk
      });
    } else if (chunk) {
      pendingRequest.onDone({
        begin: 0,
        chunk
      });
    } else {
      pendingRequest.onError?.(xhr.status);
    }
  }

  getRequestXhr(xhrId) {
    return this.pendingRequests[xhrId].xhr;
  }

  isPendingRequest(xhrId) {
    return xhrId in this.pendingRequests;
  }

  abortRequest(xhrId) {
    const xhr = this.pendingRequests[xhrId].xhr;
    delete this.pendingRequests[xhrId];
    xhr.abort();
  }

}

class PDFNetworkStream {
  constructor(source) {
    this._source = source;
    this._manager = new NetworkManager(source.url, {
      httpHeaders: source.httpHeaders,
      withCredentials: source.withCredentials
    });
    this._rangeChunkSize = source.rangeChunkSize;
    this._fullRequestReader = null;
    this._rangeRequestReaders = [];
  }

  _onRangeRequestReaderClosed(reader) {
    const i = this._rangeRequestReaders.indexOf(reader);

    if (i >= 0) {
      this._rangeRequestReaders.splice(i, 1);
    }
  }

  getFullReader() {
    (0, _util.assert)(!this._fullRequestReader, "PDFNetworkStream.getFullReader can only be called once.");
    this._fullRequestReader = new PDFNetworkStreamFullRequestReader(this._manager, this._source);
    return this._fullRequestReader;
  }

  getRangeReader(begin, end) {
    const reader = new PDFNetworkStreamRangeRequestReader(this._manager, begin, end);
    reader.onClosed = this._onRangeRequestReaderClosed.bind(this);

    this._rangeRequestReaders.push(reader);

    return reader;
  }

  cancelAllRequests(reason) {
    this._fullRequestReader?.cancel(reason);

    for (const reader of this._rangeRequestReaders.slice(0)) {
      reader.cancel(reason);
    }
  }

}

exports.PDFNetworkStream = PDFNetworkStream;

class PDFNetworkStreamFullRequestReader {
  constructor(manager, source) {
    this._manager = manager;
    const args = {
      onHeadersReceived: this._onHeadersReceived.bind(this),
      onDone: this._onDone.bind(this),
      onError: this._onError.bind(this),
      onProgress: this._onProgress.bind(this)
    };
    this._url = source.url;
    this._fullRequestId = manager.requestFull(args);
    this._headersReceivedCapability = (0, _util.createPromiseCapability)();
    this._disableRange = source.disableRange || false;
    this._contentLength = source.length;
    this._rangeChunkSize = source.rangeChunkSize;

    if (!this._rangeChunkSize && !this._disableRange) {
      this._disableRange = true;
    }

    this._isStreamingSupported = false;
    this._isRangeSupported = false;
    this._cachedChunks = [];
    this._requests = [];
    this._done = false;
    this._storedError = undefined;
    this._filename = null;
    this.onProgress = null;
  }

  _onHeadersReceived() {
    const fullRequestXhrId = this._fullRequestId;

    const fullRequestXhr = this._manager.getRequestXhr(fullRequestXhrId);

    const getResponseHeader = name => {
      return fullRequestXhr.getResponseHeader(name);
    };

    const {
      allowRangeRequests,
      suggestedLength
    } = (0, _network_utils.validateRangeRequestCapabilities)({
      getResponseHeader,
      isHttp: this._manager.isHttp,
      rangeChunkSize: this._rangeChunkSize,
      disableRange: this._disableRange
    });

    if (allowRangeRequests) {
      this._isRangeSupported = true;
    }

    this._contentLength = suggestedLength || this._contentLength;
    this._filename = (0, _network_utils.extractFilenameFromHeader)(getResponseHeader);

    if (this._isRangeSupported) {
      this._manager.abortRequest(fullRequestXhrId);
    }

    this._headersReceivedCapability.resolve();
  }

  _onDone(data) {
    if (data) {
      if (this._requests.length > 0) {
        const requestCapability = this._requests.shift();

        requestCapability.resolve({
          value: data.chunk,
          done: false
        });
      } else {
        this._cachedChunks.push(data.chunk);
      }
    }

    this._done = true;

    if (this._cachedChunks.length > 0) {
      return;
    }

    for (const requestCapability of this._requests) {
      requestCapability.resolve({
        value: undefined,
        done: true
      });
    }

    this._requests.length = 0;
  }

  _onError(status) {
    this._storedError = (0, _network_utils.createResponseStatusError)(status, this._url);

    this._headersReceivedCapability.reject(this._storedError);

    for (const requestCapability of this._requests) {
      requestCapability.reject(this._storedError);
    }

    this._requests.length = 0;
    this._cachedChunks.length = 0;
  }

  _onProgress(evt) {
    this.onProgress?.({
      loaded: evt.loaded,
      total: evt.lengthComputable ? evt.total : this._contentLength
    });
  }

  get filename() {
    return this._filename;
  }

  get isRangeSupported() {
    return this._isRangeSupported;
  }

  get isStreamingSupported() {
    return this._isStreamingSupported;
  }

  get contentLength() {
    return this._contentLength;
  }

  get headersReady() {
    return this._headersReceivedCapability.promise;
  }

  async read() {
    if (this._storedError) {
      throw this._storedError;
    }

    if (this._cachedChunks.length > 0) {
      const chunk = this._cachedChunks.shift();

      return {
        value: chunk,
        done: false
      };
    }

    if (this._done) {
      return {
        value: undefined,
        done: true
      };
    }

    const requestCapability = (0, _util.createPromiseCapability)();

    this._requests.push(requestCapability);

    return requestCapability.promise;
  }

  cancel(reason) {
    this._done = true;

    this._headersReceivedCapability.reject(reason);

    for (const requestCapability of this._requests) {
      requestCapability.resolve({
        value: undefined,
        done: true
      });
    }

    this._requests.length = 0;

    if (this._manager.isPendingRequest(this._fullRequestId)) {
      this._manager.abortRequest(this._fullRequestId);
    }

    this._fullRequestReader = null;
  }

}

class PDFNetworkStreamRangeRequestReader {
  constructor(manager, begin, end) {
    this._manager = manager;
    const args = {
      onDone: this._onDone.bind(this),
      onError: this._onError.bind(this),
      onProgress: this._onProgress.bind(this)
    };
    this._url = manager.url;
    this._requestId = manager.requestRange(begin, end, args);
    this._requests = [];
    this._queuedChunk = null;
    this._done = false;
    this._storedError = undefined;
    this.onProgress = null;
    this.onClosed = null;
  }

  _close() {
    this.onClosed?.(this);
  }

  _onDone(data) {
    const chunk = data.chunk;

    if (this._requests.length > 0) {
      const requestCapability = this._requests.shift();

      requestCapability.resolve({
        value: chunk,
        done: false
      });
    } else {
      this._queuedChunk = chunk;
    }

    this._done = true;

    for (const requestCapability of this._requests) {
      requestCapability.resolve({
        value: undefined,
        done: true
      });
    }

    this._requests.length = 0;

    this._close();
  }

  _onError(status) {
    this._storedError = (0, _network_utils.createResponseStatusError)(status, this._url);

    for (const requestCapability of this._requests) {
      requestCapability.reject(this._storedError);
    }

    this._requests.length = 0;
    this._queuedChunk = null;
  }

  _onProgress(evt) {
    if (!this.isStreamingSupported) {
      this.onProgress?.({
        loaded: evt.loaded
      });
    }
  }

  get isStreamingSupported() {
    return false;
  }

  async read() {
    if (this._storedError) {
      throw this._storedError;
    }

    if (this._queuedChunk !== null) {
      const chunk = this._queuedChunk;
      this._queuedChunk = null;
      return {
        value: chunk,
        done: false
      };
    }

    if (this._done) {
      return {
        value: undefined,
        done: true
      };
    }

    const requestCapability = (0, _util.createPromiseCapability)();

    this._requests.push(requestCapability);

    return requestCapability.promise;
  }

  cancel(reason) {
    this._done = true;

    for (const requestCapability of this._requests) {
      requestCapability.resolve({
        value: undefined,
        done: true
      });
    }

    this._requests.length = 0;

    if (this._manager.isPendingRequest(this._requestId)) {
      this._manager.abortRequest(this._requestId);
    }

    this._close();
  }

}