Cleaning up fonts when viewer is idle for some time

src/core/core.js

@@ -25,12 +25,13 @@
 
 var Page = (function PageClosure() {
 
-  function Page(pdfManager, xref, pageIndex, pageDict, ref) {
+  function Page(pdfManager, xref, pageIndex, pageDict, ref, fontCache) {
     this.pdfManager = pdfManager;
     this.pageIndex = pageIndex;
     this.pageDict = pageDict;
     this.xref = xref;
     this.ref = ref;
+    this.fontCache = fontCache;
     this.idCounters = {
       obj: 0
     };
@@ -160,7 +161,7 @@ var Page = (function PageClosure() {
       var partialEvaluator = new PartialEvaluator(
             pdfManager, this.xref, handler,
             this.pageIndex, 'p' + this.pageIndex + '_',
-            this.idCounters);
+            this.idCounters, this.fontCache);
 
       var dataPromises = Promise.all(
           [contentStreamPromise, resourcesPromise], reject);
@@ -226,7 +227,7 @@ var Page = (function PageClosure() {
         var partialEvaluator = new PartialEvaluator(
               pdfManager, self.xref, handler,
               self.pageIndex, 'p' + self.pageIndex + '_',
-              self.idCounters);
+              self.idCounters, self.fontCache);
 
         var bidiTexts = partialEvaluator.getTextContent(contentStream,
                                                         self.resources);
@@ -496,6 +497,10 @@ var PDFDocument = (function PDFDocumentClosure() {
 
     getPage: function PDFDocument_getPage(pageIndex) {
       return this.catalog.getPage(pageIndex);
+    },
+
+    cleanup: function PDFDocument_cleanup() {
+      return this.catalog.cleanup();
     }
   };
 

src/core/evaluator.js

@@ -26,7 +26,7 @@
 
 var PartialEvaluator = (function PartialEvaluatorClosure() {
   function PartialEvaluator(pdfManager, xref, handler, pageIndex,
-                            uniquePrefix, idCounters) {
+                            uniquePrefix, idCounters, fontCache) {
     this.state = new EvalState();
     this.stateStack = [];
 
@@ -36,7 +36,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
     this.pageIndex = pageIndex;
     this.uniquePrefix = uniquePrefix;
     this.idCounters = idCounters;
-    this.fontCache = new RefSetCache();
+    this.fontCache = fontCache;
   }
 
   // Specifies properties for each command

src/core/obj.js

@@ -189,7 +189,7 @@ var RefSet = (function RefSetClosure() {
 
 var RefSetCache = (function RefSetCacheClosure() {
   function RefSetCache() {
-    this.dict = {};
+    this.dict = Object.create(null);
   }
 
   RefSetCache.prototype = {
@@ -203,6 +203,16 @@ var RefSetCache = (function RefSetCacheClosure() {
 
     put: function RefSetCache_put(ref, obj) {
       this.dict['R' + ref.num + '.' + ref.gen] = obj;
+    },
+
+    forEach: function RefSetCache_forEach(fn, thisArg) {
+      for (var i in this.dict) {
+        fn.call(thisArg, this.dict[i]);
+      }
+    },
+
+    clear: function RefSetCache_clear() {
+      this.dict = Object.create(null);
     }
   };
 
@@ -214,6 +224,7 @@ var Catalog = (function CatalogClosure() {
     this.pdfManager = pdfManager;
     this.xref = xref;
     this.catDict = xref.getCatalogObj();
+    this.fontCache = new RefSetCache();
     assertWellFormed(isDict(this.catDict),
       'catalog object is not a dictionary');
 
@@ -400,13 +411,22 @@ var Catalog = (function CatalogClosure() {
       return shadow(this, 'javaScript', javaScript);
     },
 
+    cleanup: function Catalog_cleanup() {
+      this.fontCache.forEach(function (font) {
+        delete font.sent;
+        delete font.translated;
+      });
+      this.fontCache.clear();
+    },
+
     getPage: function Catalog_getPage(pageIndex) {
       if (!(pageIndex in this.pagePromises)) {
         this.pagePromises[pageIndex] = this.getPageDict(pageIndex).then(
           function (a) {
             var dict = a[0];
             var ref = a[1];
-            return new Page(this.pdfManager, this.xref, pageIndex, dict, ref);
+            return new Page(this.pdfManager, this.xref, pageIndex, dict, ref,
+                            this.fontCache);
           }.bind(this)
         );
       }

src/core/pdf_manager.js

@@ -46,6 +46,10 @@ var BasePdfManager = (function BasePdfManagerClosure() {
       return this.pdfModel.getPage(pageIndex);
     },
 
+    cleanup: function BasePdfManager_cleanup() {
+      return this.pdfModel.cleanup();
+    },
+
     ensure: function BasePdfManager_ensure(obj, prop, args) {
       return new NotImplementedException();
     },

src/core/worker.js

@@ -373,6 +373,11 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
       });
     });
 
+    handler.on('Cleanup', function wphCleanup(data, promise) {
+      pdfManager.cleanup();
+      promise.resolve(true);
+    });
+
     handler.on('Terminate', function wphTerminate(data, promise) {
       pdfManager.terminate();
       promise.resolve();

src/display/api.js

@@ -270,6 +270,9 @@ var PDFDocumentProxy = (function PDFDocumentProxyClosure() {
     dataLoaded: function PDFDocumentProxy_dataLoaded() {
       return this.transport.dataLoaded();
     },
+    cleanup: function PDFDocumentProxy_cleanup() {
+      this.transport.startCleanup();
+    },
     destroy: function PDFDocumentProxy_destroy() {
       this.transport.destroy();
     }
@@ -892,6 +895,21 @@ var WorkerTransport = (function WorkerTransportClosure() {
         }
       );
       return promise;
+    },
+
+    startCleanup: function WorkerTransport_startCleanup() {
+      this.messageHandler.send('Cleanup', null,
+        function endCleanup() {
+          for (var i = 0, ii = this.pageCache.length; i < ii; i++) {
+            var page = this.pageCache[i];
+            if (page) {
+              page.destroy();
+            }
+          }
+          this.commonObjs.clear();
+          FontLoader.clear();
+        }.bind(this)
+      );
     }
   };
   return WorkerTransport;

src/display/font_loader.js

@@ -33,6 +33,12 @@ var FontLoader = {
     var styleSheet = styleElement.sheet;
     styleSheet.insertRule(rule, styleSheet.cssRules.length);
   },
+  clear: function fontLoaderClear() {
+    var styleElement = document.getElementById('PDFJS_FONT_STYLE_TAG');
+    if (styleElement) {
+      styleElement.parentNode.removeChild(styleElement);
+    }
+  },
 //#if !(MOZCENTRAL)
   get loadTestFont() {
     // This is a CFF font with 1 glyph for '.' that fills its entire width and

web/page_view.js

@@ -67,12 +67,16 @@ var PageView = function pageView(container, id, scale,
     }
   };
 
-  this.reset = function pageViewReset() {
+  this.resetRenderingState = function  pageViewResetRenderingState() {
     if (this.renderTask) {
       this.renderTask.cancel();
     }
     this.resume = null;
     this.renderingState = RenderingStates.INITIAL;
+  };
+
+  this.reset = function pageViewReset() {
+    this.resetRenderingState();
 
     div.style.width = Math.floor(this.viewport.width) + 'px';
     div.style.height = Math.floor(this.viewport.height) + 'px';

web/viewer.js

@@ -38,6 +38,7 @@ var SCALE_SELECT_CONTAINER_PADDING = 8;
 var SCALE_SELECT_PADDING = 22;
 var THUMBNAIL_SCROLL_MARGIN = -19;
 var USE_ONLY_CSS_ZOOM = false;
+var CLEANUP_TIMEOUT = 30000;
 //#if B2G
 //USE_ONLY_CSS_ZOOM = true;
 //#endif
@@ -106,6 +107,7 @@ var PDFView = {
   lastScroll: 0,
   previousPageNumber: 1,
   isViewerEmbedded: (window.parent !== window),
+  idleTimeout: null,
 
   // called once when the document is loaded
   initialize: function pdfViewInitialize() {
@@ -1011,6 +1013,11 @@ var PDFView = {
   },
 
   renderHighestPriority: function pdfViewRenderHighestPriority() {
+    if (PDFView.idleTimeout) {
+      clearTimeout(PDFView.idleTimeout);
+      PDFView.idleTimeout = null;
+    }
+
     // Pages have a higher priority than thumbnails, so check them first.
     var visiblePages = this.getVisiblePages();
     var pageView = this.getHighestPriority(visiblePages, this.pages,
@@ -1025,9 +1032,24 @@ var PDFView = {
       var thumbView = this.getHighestPriority(visibleThumbs,
                                               this.thumbnails,
                                               this.thumbnailViewScroll.down);
-      if (thumbView)
+      if (thumbView) {
         this.renderView(thumbView, 'thumbnail');
+        return;
+      }
     }
+
+    PDFView.idleTimeout = setTimeout(function () {
+      PDFView.cleanup();
+    }, CLEANUP_TIMEOUT);
+  },
+
+  cleanup: function pdfViewCleanup() {
+    for (var i = 0, ii = this.pages.length; i < ii; i++) {
+      if (this.pages[i]) {
+        this.pages[i].resetRenderingState();
+      }
+    }
+    this.pdfDocument.cleanup();
   },
 
   getHighestPriority: function pdfViewGetHighestPriority(visible, views,