Adds destroy method to the document loading task.

Also renames PDFPageProxy.destroy method to cleanup.

src/core/worker.js

@@ -25,6 +25,14 @@
 var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
   setup: function wphSetup(handler) {
     var pdfManager;
+    var terminated = false;
+    var cancelXHRs = null;
+
+    function ensureNotTerminated() {
+      if (terminated) {
+        throw new Error('Worker was terminated');
+      }
+    }
 
     function loadDocument(recoveryMode) {
       var loadDocumentCapability = createPromiseCapability();
@@ -61,13 +69,14 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
 
     function getPdfManager(data) {
       var pdfManagerCapability = createPromiseCapability();
+      var pdfManager;
 
       var source = data.source;
       var disableRange = data.disableRange;
       if (source.data) {
         try {
           pdfManager = new LocalPdfManager(source.data, source.password);
-          pdfManagerCapability.resolve();
+          pdfManagerCapability.resolve(pdfManager);
         } catch (ex) {
           pdfManagerCapability.reject(ex);
         }
@@ -75,7 +84,7 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
       } else if (source.chunkedViewerLoading) {
         try {
           pdfManager = new NetworkPdfManager(source, handler);
-          pdfManagerCapability.resolve();
+          pdfManagerCapability.resolve(pdfManager);
         } catch (ex) {
           pdfManagerCapability.reject(ex);
         }
@@ -136,6 +145,7 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
           } catch (ex) {
             pdfManagerCapability.reject(ex);
           }
+          cancelXHRs = null;
         },
 
         onProgressiveData: source.disableStream ? null :
@@ -176,10 +186,11 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
           // the data is array, instantiating directly from it
           try {
             pdfManager = new LocalPdfManager(pdfFile, source.password);
-            pdfManagerCapability.resolve();
+            pdfManagerCapability.resolve(pdfManager);
           } catch (ex) {
             pdfManagerCapability.reject(ex);
           }
+          cancelXHRs = null;
         },
 
         onError: function onError(status) {
@@ -194,6 +205,7 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
               ') while retrieving PDF "' + source.url + '".', status);
             handler.send('UnexpectedResponse', exception);
           }
+          cancelXHRs = null;
         },
 
         onProgress: function onProgress(evt) {
@@ -204,6 +216,10 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
         }
       });
 
+      cancelXHRs = function () {
+        networkManager.abortRequest(fullRequestXhrId);
+      };
+
       return pdfManagerCapability.promise;
     }
 
@@ -236,8 +252,8 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
     });
 
     handler.on('GetDocRequest', function wphSetupDoc(data) {
-
       var onSuccess = function(doc) {
+        ensureNotTerminated();
         handler.send('GetDoc', { pdfInfo: doc });
       };
 
@@ -260,6 +276,8 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
         }
       };
 
+      ensureNotTerminated();
+
       PDFJS.maxImageSize = data.maxImageSize === undefined ?
                            -1 : data.maxImageSize;
       PDFJS.disableFontFace = data.disableFontFace;
@@ -269,13 +287,26 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
                            null : data.cMapUrl;
       PDFJS.cMapPacked = data.cMapPacked === true;
 
-      getPdfManager(data).then(function () {
+      getPdfManager(data).then(function (newPdfManager) {
+        if (terminated) {
+          // We were in a process of setting up the manager, but it got
+          // terminated in the middle.
+          newPdfManager.terminate();
+          throw new Error('Worker was terminated');
+        }
+
+        pdfManager = newPdfManager;
+
         handler.send('PDFManagerReady', null);
         pdfManager.onLoadedStream().then(function(stream) {
           handler.send('DataLoaded', { length: stream.bytes.byteLength });
         });
       }).then(function pdfManagerReady() {
+        ensureNotTerminated();
+
         loadDocument(false).then(onSuccess, function loadFailure(ex) {
+          ensureNotTerminated();
+
           // Try again with recoveryMode == true
           if (!(ex instanceof XRefParseException)) {
             if (ex instanceof PasswordException) {
@@ -290,6 +321,8 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
 
           pdfManager.requestLoadedStream();
           pdfManager.onLoadedStream().then(function() {
+            ensureNotTerminated();
+
             loadDocument(true).then(onSuccess, onFailure);
           });
         }, onFailure);
@@ -441,7 +474,14 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
     });
 
     handler.on('Terminate', function wphTerminate(data) {
-      pdfManager.terminate();
+      terminated = true;
+      if (pdfManager) {
+        pdfManager.terminate();
+        pdfManager = null;
+      }
+      if (cancelXHRs) {
+        cancelXHRs();
+      }
     });
   }
 };