Leave initial request open until the viewer is ready to switch to range requests.

src/core/chunked_stream.js

@@ -30,6 +30,7 @@ var ChunkedStream = (function ChunkedStreamClosure() {
     this.numChunksLoaded = 0;
     this.numChunks = Math.ceil(length / chunkSize);
     this.manager = manager;
+    this.initialDataLength = 0;
   }
 
   // required methods for a stream. if a particular stream does not
@@ -77,11 +78,26 @@ var ChunkedStream = (function ChunkedStreamClosure() {
       }
     },
 
+    onReceiveInitialData: function (data) {
+      this.bytes.set(data);
+      this.initialDataLength = data.length;
+      var endChunk = this.end === data.length ?
+                     this.numChunks : Math.floor(data.length / this.chunkSize);
+      for (var i = 0; i < endChunk; i++) {
+        this.loadedChunks[i] = true;
+        ++this.numChunksLoaded;
+      }
+    },
+
     ensureRange: function ChunkedStream_ensureRange(begin, end) {
       if (begin >= end) {
         return;
       }
 
+      if (end <= this.initialDataLength) {
+        return;
+      }
+
       var chunkSize = this.chunkSize;
       var beginChunk = Math.floor(begin / chunkSize);
       var endChunk = Math.floor((end - 1) / chunkSize) + 1;
@@ -243,10 +259,25 @@ var ChunkedStreamManager = (function ChunkedStreamManagerClosure() {
     this.callbacksByRequest = {};
 
     this.loadedStream = new Promise();
+    if (args.initialData) {
+      this.setInitialData(args.initialData);
+    }
   }
 
   ChunkedStreamManager.prototype = {
 
+    setInitialData: function ChunkedStreamManager_setInitialData(data) {
+      this.stream.onReceiveInitialData(data);
+      if (this.stream.allChunksLoaded()) {
+        this.loadedStream.resolve(this.stream);
+      } else if (this.msgHandler) {
+        this.msgHandler.send('DocProgress', {
+          loaded: data.length,
+          total: this.length
+        });
+      }
+    },
+
     onLoadedStream: function ChunkedStreamManager_getLoadedStream() {
       return this.loadedStream;
     },

src/core/pdf_manager.js

@@ -139,7 +139,8 @@ var NetworkPdfManager = (function NetworkPdfManagerClosure() {
       msgHandler: msgHandler,
       httpHeaders: args.httpHeaders,
       chunkedViewerLoading: args.chunkedViewerLoading,
-      disableAutoFetch: args.disableAutoFetch
+      disableAutoFetch: args.disableAutoFetch,
+      initialData: args.initialData
     };
     this.streamManager = new ChunkedStreamManager(args.length, CHUNK_SIZE,
                                                   args.url, params);

src/display/api.js

@@ -98,6 +98,9 @@ PDFJS.pdfBug = PDFJS.pdfBug === undefined ? false : PDFJS.pdfBug;
  *  - data  - A typed array with PDF data.
  *  - httpHeaders - Basic authentication headers.
  *  - password - For decrypting password-protected PDFs.
+ *  - initialData - A typed array with the first portion or all of the pdf data.
+ *                  Used by the extension since some data is already loaded
+ *                  before the switch to range requests. 
  *
  * @param {object} pdfDataRangeTransport is optional. It is used if you want
  * to manually serve range requests for data in the PDF. See viewer.js for