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();