Refactors Cache into PDFPageViewBuffer

web/pdf_page_view.js

@@ -25,7 +25,6 @@
  * @property {number} scale - The page scale display.
  * @property {PageViewport} defaultViewport - The page viewport.
  * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
- * @property {Cache} cache - The page cache.
  * @property {IPDFTextLayerFactory} textLayerFactory
  * @property {IPDFAnnotationsLayerFactory} annotationsLayerFactory
  */
@@ -45,7 +44,6 @@ var PDFPageView = (function PDFPageViewClosure() {
     var scale = options.scale;
     var defaultViewport = options.defaultViewport;
     var renderingQueue = options.renderingQueue;
-    var cache = options.cache;
     var textLayerFactory = options.textLayerFactory;
     var annotationsLayerFactory = options.annotationsLayerFactory;
 
@@ -59,13 +57,15 @@ var PDFPageView = (function PDFPageViewClosure() {
     this.hasRestrictedScaling = false;
 
     this.renderingQueue = renderingQueue;
-    this.cache = cache;
     this.textLayerFactory = textLayerFactory;
     this.annotationsLayerFactory = annotationsLayerFactory;
 
     this.renderingState = RenderingStates.INITIAL;
     this.resume = null;
 
+    this.onBeforeDraw = null;
+    this.onAfterDraw = null;
+
     this.textLayer = null;
 
     this.zoomLayer = null;
@@ -447,9 +447,9 @@ var PDFPageView = (function PDFPageViewClosure() {
       }
       div.setAttribute('data-loaded', true);
 
-      // Add the page to the cache at the start of drawing. That way it can be
-      // evicted from the cache and destroyed even if we pause its rendering.
-      this.cache.push(this);
+      if (self.onBeforeDraw) {
+        self.onBeforeDraw();
+      }
     },
 
     beforePrint: function PDFPageView_beforePrint() {

web/pdf_viewer.js

@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
- /*globals watchScroll, Cache, DEFAULT_CACHE_SIZE, PDFPageView, UNKNOWN_SCALE,
+ /*globals watchScroll, PDFPageView, UNKNOWN_SCALE,
            SCROLLBAR_PADDING, VERTICAL_PADDING, MAX_AUTO_SCALE, CSS_UNITS,
            DEFAULT_SCALE, scrollIntoView, getVisibleElements, RenderingStates,
            PDFJS, Promise, TextLayerBuilder, PDFRenderingQueue,
@@ -30,6 +30,7 @@ var PresentationModeState = {
 };
 
 var IGNORE_CURRENT_POSITION_ON_ZOOM = false;
+var DEFAULT_CACHE_SIZE = 10;
 
 //#include pdf_rendering_queue.js
 //#include pdf_page_view.js
@@ -52,6 +53,26 @@ var IGNORE_CURRENT_POSITION_ON_ZOOM = false;
  * @implements {IRenderableView}
  */
 var PDFViewer = (function pdfViewer() {
+  function PDFPageViewBuffer(size) {
+    var data = [];
+    this.push = function cachePush(view) {
+      var i = data.indexOf(view);
+      if (i >= 0) {
+        data.splice(i, 1);
+      }
+      data.push(view);
+      if (data.length > size) {
+        data.shift().destroy();
+      }
+    };
+    this.resize = function (newSize) {
+      size = newSize;
+      while (data.length > size) {
+        data.shift().destroy();
+      }
+    };
+  }
+
   /**
    * @constructs PDFViewer
    * @param {PDFViewerOptions} options
@@ -212,7 +233,13 @@ var PDFViewer = (function pdfViewer() {
       });
       this.onePageRendered = onePageRendered;
 
-      var bindOnAfterDraw = function (pageView) {
+      var bindOnAfterAndBeforeDraw = function (pageView) {
+        pageView.onBeforeDraw = function pdfViewLoadOnBeforeDraw() {
+          // Add the page to the buffer at the start of drawing. That way it can
+          // be evicted from the buffer and destroyed even if we pause its
+          // rendering.
+          self._buffer.push(this);
+        };
         // when page is painted, using the image as thumbnail base
         pageView.onAfterDraw = function pdfViewLoadOnAfterDraw() {
           if (!isOnePageRenderedResolved) {
@@ -246,11 +273,10 @@ var PDFViewer = (function pdfViewer() {
             scale: scale,
             defaultViewport: viewport.clone(),
             renderingQueue: this.renderingQueue,
-            cache: this.cache,
             textLayerFactory: textLayerFactory,
             annotationsLayerFactory: this
           });
-          bindOnAfterDraw(pageView);
+          bindOnAfterAndBeforeDraw(pageView);
           this.pages.push(pageView);
         }
 
@@ -291,11 +317,11 @@ var PDFViewer = (function pdfViewer() {
     },
 
     _resetView: function () {
-      this.cache = new Cache(DEFAULT_CACHE_SIZE);
       this.pages = [];
       this._currentPageNumber = 1;
       this._currentScale = UNKNOWN_SCALE;
       this._currentScaleValue = null;
+      this._buffer = new PDFPageViewBuffer(DEFAULT_CACHE_SIZE);
       this.location = null;
       this._pagesRotation = 0;
       this._pagesRequests = [];
@@ -538,7 +564,7 @@ var PDFViewer = (function pdfViewer() {
 
       var suggestedCacheSize = Math.max(DEFAULT_CACHE_SIZE,
           2 * visiblePages.length + 1);
-      this.cache.resize(suggestedCacheSize);
+      this._buffer.resize(suggestedCacheSize);
 
       this.renderingQueue.renderHighestPriority(visible);
 

web/ui_utils.js

@@ -22,7 +22,6 @@ var UNKNOWN_SCALE = 0;
 var MAX_AUTO_SCALE = 1.25;
 var SCROLLBAR_PADDING = 40;
 var VERTICAL_PADDING = 5;
-var DEFAULT_CACHE_SIZE = 10;
 
 // optimised CSS custom property getter/setter
 var CustomStyle = (function CustomStyleClosure() {
@@ -349,23 +348,3 @@ var ProgressBar = (function ProgressBarClosure() {
 
   return ProgressBar;
 })();
-
-var Cache = function cacheCache(size) {
-  var data = [];
-  this.push = function cachePush(view) {
-    var i = data.indexOf(view);
-    if (i >= 0) {
-      data.splice(i, 1);
-    }
-    data.push(view);
-    if (data.length > size) {
-      data.shift().destroy();
-    }
-  };
-  this.resize = function (newSize) {
-    size = newSize;
-    while (data.length > size) {
-      data.shift().destroy();
-    }
-  };
-};