Makes PDF data reading Streams API friendly.

src/core/network.js

@@ -295,13 +295,347 @@ var NetworkManager = (function NetworkManagerClosure() {
 //#if !(FIREFOX || MOZCENTRAL)
 (function (root, factory) {
   if (typeof define === 'function' && define.amd) {
-    define('pdfjs/core/network', ['exports'], factory);
+    define('pdfjs/core/network', ['exports', 'pdfjs/shared/util',
+      'pdfjs/core/worker'], factory);
   } else if (typeof exports !== 'undefined') {
-    factory(exports);
+    factory(exports, require('../shared/util.js'), require('./worker.js'));
   } else {
-    factory((root.pdfjsCoreNetwork = {}));
+    factory((root.pdfjsCoreNetwork = {}), root.pdfjsSharedUtil,
+      root.pdfjsCoreWorker);
   }
-}(this, function (exports) {
+}(this, function (exports, sharedUtil, coreWorker) {
+
+  var assert = sharedUtil.assert;
+  var createPromiseCapability = sharedUtil.createPromiseCapability;
+  var isInt = sharedUtil.isInt;
+  var MissingPDFException = sharedUtil.MissingPDFException;
+  var UnexpectedResponseException = sharedUtil.UnexpectedResponseException;
+
+  /** @implements {IPDFStream} */
+  function PDFNetworkStream(options) {
+    this._options = options;
+    var source = options.source;
+    this._manager = new NetworkManager(source.url, {
+      httpHeaders: source.httpHeaders,
+      withCredentials: source.withCredentials
+    });
+    this._rangeChunkSize = source.rangeChunkSize;
+    this._fullRequestReader = null;
+    this._rangeRequestReaders = [];
+  }
+
+  PDFNetworkStream.prototype = {
+    _onRangeRequestReaderClosed:
+        function PDFNetworkStream_onRangeRequestReaderClosed(reader) {
+      var i = this._rangeRequestReaders.indexOf(reader);
+      if (i >= 0) {
+        this._rangeRequestReaders.splice(i, 1);
+      }
+    },
+
+    getFullReader: function PDFNetworkStream_getFullReader() {
+      assert(!this._fullRequestReader);
+      this._fullRequestReader =
+        new PDFNetworkStreamFullRequestReader(this._manager, this._options);
+      return this._fullRequestReader;
+    },
+
+    getRangeReader: function PDFNetworkStream_getRangeReader(begin, end) {
+      var reader = new PDFNetworkStreamRangeRequestReader(this._manager,
+                                                          begin, end);
+      reader.onClosed = this._onRangeRequestReaderClosed.bind(this);
+      this._rangeRequestReaders.push(reader);
+      return reader;
+    },
+
+    cancelAllRequests: function PDFNetworkStream_cancelAllRequests(reason) {
+      if (this._fullRequestReader) {
+        this._fullRequestReader.cancel(reason);
+      }
+      var readers = this._rangeRequestReaders.slice(0);
+      readers.forEach(function (reader) {
+        reader.cancel(reason);
+      });
+    }
+  };
+
+  /** @implements {IPDFStreamReader} */
+  function PDFNetworkStreamFullRequestReader(manager, options) {
+    this._manager = manager;
+
+    var source = options.source;
+    var args = {
+      onHeadersReceived: this._onHeadersReceived.bind(this),
+      onProgressiveData: source.disableStream ? null :
+                         this._onProgressiveData.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 = createPromiseCapability();
+    this._disableRange = options.disableRange || false;
+    this._contentLength = source.length; // optional
+    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.onProgress = null;
+  }
+
+  PDFNetworkStreamFullRequestReader.prototype = {
+    _validateRangeRequestCapabilities: function
+        PDFNetworkStreamFullRequestReader_validateRangeRequestCapabilities() {
+
+      if (this._disableRange) {
+        return false;
+      }
+
+      var networkManager = this._manager;
+      var fullRequestXhrId = this._fullRequestId;
+      var fullRequestXhr = networkManager.getRequestXhr(fullRequestXhrId);
+      if (fullRequestXhr.getResponseHeader('Accept-Ranges') !== 'bytes') {
+        return false;
+      }
+
+      var contentEncoding =
+        fullRequestXhr.getResponseHeader('Content-Encoding') || 'identity';
+      if (contentEncoding !== 'identity') {
+        return false;
+      }
+
+      var length = fullRequestXhr.getResponseHeader('Content-Length');
+      length = parseInt(length, 10);
+      if (!isInt(length)) {
+        return false;
+      }
+
+      this._contentLength = length; // setting right content length
+
+      if (length <= 2 * this._rangeChunkSize) {
+        // The file size is smaller than the size of two chunks, so it does
+        // not make any sense to abort the request and retry with a range
+        // request.
+        return false;
+      }
+
+      return true;
+    },
+
+    _onHeadersReceived:
+        function PDFNetworkStreamFullRequestReader_onHeadersReceived() {
+
+      if (this._validateRangeRequestCapabilities()) {
+        this._isRangeSupported = true;
+      }
+
+      var networkManager = this._manager;
+      var fullRequestXhrId = this._fullRequestId;
+      if (networkManager.isStreamingRequest(fullRequestXhrId)) {
+        // We can continue fetching when progressive loading is enabled,
+        // and we don't need the autoFetch feature.
+        this._isStreamingSupported = true;
+      } else if (this._isRangeSupported) {
+        // NOTE: by cancelling the full request, and then issuing range
+        // requests, there will be an issue for sites where you can only
+        // request the pdf once. However, if this is the case, then the
+        // server should not be returning that it can support range
+        // requests.
+        networkManager.abortRequest(fullRequestXhrId);
+      }
+
+      this._headersReceivedCapability.resolve();
+    },
+
+    _onProgressiveData:
+        function PDFNetworkStreamFullRequestReader_onProgressiveData(chunk) {
+      if (this._requests.length > 0) {
+        var requestCapability = this._requests.shift();
+        requestCapability.resolve({value: chunk, done: false});
+      } else {
+        this._cachedChunks.push(chunk);
+      }
+    },
+
+    _onDone: function PDFNetworkStreamFullRequestReader_onDone(args) {
+      if (args) {
+        this._onProgressiveData(args.chunk);
+      }
+      this._done = true;
+      if (this._cachedChunks.length > 0) {
+        return;
+      }
+      this._requests.forEach(function (requestCapability) {
+        requestCapability.resolve({value: undefined, done: true});
+      });
+      this._requests = [];
+    },
+
+    _onError: function PDFNetworkStreamFullRequestReader_onError(status) {
+      var url = this._url;
+      var exception;
+      if (status === 404 || status === 0 && /^file:/.test(url)) {
+        exception = new MissingPDFException('Missing PDF "' + url + '".');
+      } else {
+        exception = new UnexpectedResponseException(
+          'Unexpected server response (' + status +
+          ') while retrieving PDF "' + url + '".', status);
+      }
+      this._storedError = exception;
+      this._headersReceivedCapability.reject(exception);
+      this._requests.forEach(function (requestCapability) {
+        requestCapability.reject(exception);
+      });
+      this._requests = [];
+      this._cachedChunks = [];
+    },
+
+    _onProgress: function PDFNetworkStreamFullRequestReader_onProgress(data) {
+      if (this.onProgress) {
+        this.onProgress({
+          loaded: data.loaded,
+          total: data.lengthComputable ? data.total : this._contentLength
+        });
+      }
+    },
+
+    get isRangeSupported() {
+      return this._isRangeSupported;
+    },
+
+    get isStreamingSupported() {
+      return this._isStreamingSupported;
+    },
+
+    get contentLength() {
+      return this._contentLength;
+    },
+
+    get headersReady() {
+      return this._headersReceivedCapability.promise;
+    },
+
+    read: function PDFNetworkStreamFullRequestReader_read() {
+      if (this._storedError) {
+        return Promise.reject(this._storedError);
+      }
+      if (this._cachedChunks.length > 0) {
+        var chunk = this._cachedChunks.shift();
+        return Promise.resolve(chunk);
+      }
+      if (this._done) {
+        return Promise.resolve({value: undefined, done: true});
+      }
+      var requestCapability = createPromiseCapability();
+      this._requests.push(requestCapability);
+      return requestCapability.promise;
+    },
+
+    cancel: function PDFNetworkStreamFullRequestReader_cancel(reason) {
+      this._done = true;
+      this._headersReceivedCapability.reject(reason);
+      this._requests.forEach(function (requestCapability) {
+        requestCapability.resolve({value: undefined, done: true});
+      });
+      this._requests = [];
+      if (this._manager.isPendingRequest(this._fullRequestId)) {
+        this._manager.abortRequest(this._fullRequestId);
+      }
+      this._fullRequestReader = null;
+    }
+  };
+
+  /** @implements {IPDFStreamRangeReader} */
+  function PDFNetworkStreamRangeRequestReader(manager, begin, end) {
+    this._manager = manager;
+    var args = {
+      onDone: this._onDone.bind(this),
+      onProgress: this._onProgress.bind(this)
+    };
+    this._requestId = manager.requestRange(begin, end, args);
+    this._requests = [];
+    this._queuedChunk = null;
+    this._done = false;
+
+    this.onProgress = null;
+    this.onClosed = null;
+  }
+
+  PDFNetworkStreamRangeRequestReader.prototype = {
+    _close: function PDFNetworkStreamRangeRequestReader_close() {
+      if (this.onClosed) {
+        this.onClosed(this);
+      }
+    },
+
+    _onDone: function PDFNetworkStreamRangeRequestReader_onDone(data) {
+      var chunk = data.chunk;
+      if (this._requests.length > 0) {
+        var requestCapability = this._requests.shift();
+        requestCapability.resolve({value: chunk, done: false});
+      } else {
+        this._queuedChunk = chunk;
+      }
+      this._done = true;
+      this._requests.forEach(function (requestCapability) {
+        requestCapability.resolve({value: undefined, done: true});
+      });
+      this._requests = [];
+      this._close();
+    },
+
+    _onProgress: function PDFNetworkStreamRangeRequestReader_onProgress(evt) {
+      if (!this.isStreamingSupported && this.onProgress) {
+        this.onProgress({
+          loaded: evt.loaded
+        });
+      }
+    },
+
+    get isStreamingSupported() {
+      return false; // TODO allow progressive range bytes loading
+    },
+
+    read: function PDFNetworkStreamRangeRequestReader_read() {
+      if (this._queuedChunk !== null) {
+        var chunk = this._queuedChunk;
+        this._queuedChunk = null;
+        return Promise.resolve({value: chunk, done: false});
+      }
+      if (this._done) {
+        return Promise.resolve({value: undefined, done: true});
+      }
+      var requestCapability = createPromiseCapability();
+      this._requests.push(requestCapability);
+      return requestCapability.promise;
+    },
+
+    cancel: function PDFNetworkStreamRangeRequestReader_cancel(reason) {
+      this._done = true;
+      this._requests.forEach(function (requestCapability) {
+        requestCapability.resolve({value: undefined, done: true});
+      });
+      this._requests = [];
+      if (this._manager.isPendingRequest(this._requestId)) {
+        this._manager.abortRequest(this._requestId);
+      }
+      this._close();
+    }
+  };
+
+  coreWorker.setPDFNetworkStreamClass(PDFNetworkStream);
+
+  exports.PDFNetworkStream = PDFNetworkStream;
   exports.NetworkManager = NetworkManager;
 }));
 //#endif