Merge pull request #3441 from brendandahl/less-cache

Remove caching of stream data and fix object loader for streams.

src/chunked_stream.js

@@ -46,6 +46,10 @@ var ChunkedStream = (function ChunkedStreamClosure() {
       return chunks;
     },
 
+    getBaseStreams: function ChunkedStream_getBaseStreams() {
+      return [this];
+    },
+
     allChunksLoaded: function ChunkedStream_allChunksLoaded() {
       return this.numChunksLoaded === this.numChunks;
     },

src/obj.js

@@ -960,14 +960,7 @@ var XRef = (function XRefClosure() {
         } else {
           e = parser.getObj();
         }
-        if (!isStream(e) || e instanceof JpegStream) {
-          this.cache[num] = e;
-        } else if (e instanceof Stream) {
-          e = e.makeSubStream(e.start, e.length, e.dict);
-          this.cache[num] = e;
-        } else if ('readBlock' in e) {
-          e.getBytes();
-          e = e.makeSubStream(0, e.bufferLength, e.dict);
+        if (!isStream(e)) {
           this.cache[num] = e;
         }
         return e;
@@ -1296,13 +1289,22 @@ var ObjectLoader = (function() {
             pendingRequests.push({ begin: e.begin, end: e.end });
           }
         }
-        if (currentNode instanceof ChunkedStream &&
-            currentNode.getMissingChunks().length) {
-          nodesToRevisit.push(currentNode);
-          pendingRequests.push({
-            begin: currentNode.start,
-            end: currentNode.end
-          });
+        if (currentNode && currentNode.getBaseStreams) {
+          var baseStreams = currentNode.getBaseStreams();
+          var foundMissingData = false;
+          for (var i = 0; i < baseStreams.length; i++) {
+            var stream = baseStreams[i];
+            if (stream.getMissingChunks && stream.getMissingChunks().length) {
+              foundMissingData = true;
+              pendingRequests.push({
+                begin: stream.start,
+                end: stream.end
+              });
+            }
+          }
+          if (foundMissingData) {
+            nodesToRevisit.push(currentNode);
+          }
         }
 
         addChildren(currentNode, nodesToVisit);

src/stream.js

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 /* globals bytesToString, ColorSpace, Dict, EOF, error, info, Jbig2Image,
-           JpegImage, JpxImage, Lexer */
+           JpegImage, JpxImage, Lexer, Util */
 
 'use strict';
 
@@ -202,6 +202,12 @@ var DecodeStream = (function DecodeStreamClosure() {
     },
     reset: function DecodeStream_reset() {
       this.pos = 0;
+    },
+    getBaseStreams: function DecodeStream_getBaseStreams() {
+      if (this.str && this.str.getBaseStreams) {
+        return this.str.getBaseStreams();
+      }
+      return [];
     }
   };
 
@@ -272,6 +278,19 @@ var StreamsSequenceStream = (function StreamsSequenceStreamClosure() {
     this.bufferLength = newLength;
   };
 
+  StreamsSequenceStream.prototype.getBaseStreams =
+    function StreamsSequenceStream_getBaseStreams() {
+
+    var baseStreams = [];
+    for (var i = 0, ii = this.streams.length; i < ii; i++) {
+      var stream = this.streams[i];
+      if (stream.getBaseStreams) {
+        Util.concatenateToArray(baseStreams, stream.getBaseStreams());
+      }
+    }
+    return baseStreams;
+  };
+
   return StreamsSequenceStream;
 })();
 
@@ -618,11 +637,11 @@ var FlateStream = (function FlateStreamClosure() {
 })();
 
 var PredictorStream = (function PredictorStreamClosure() {
-  function PredictorStream(stream, params) {
+  function PredictorStream(str, params) {
     var predictor = this.predictor = params.get('Predictor') || 1;
 
     if (predictor <= 1)
-      return stream; // no prediction
+      return str; // no prediction
     if (predictor !== 2 && (predictor < 10 || predictor > 15))
       error('Unsupported predictor: ' + predictor);
 
@@ -631,8 +650,8 @@ var PredictorStream = (function PredictorStreamClosure() {
     else
       this.readBlock = this.readBlockPng;
 
-    this.stream = stream;
-    this.dict = stream.dict;
+    this.str = str;
+    this.dict = str.dict;
 
     var colors = this.colors = params.get('Colors') || 1;
     var bits = this.bits = params.get('BitsPerComponent') || 8;
@@ -657,7 +676,7 @@ var PredictorStream = (function PredictorStreamClosure() {
     var bits = this.bits;
     var colors = this.colors;
 
-    var rawBytes = this.stream.getBytes(rowBytes);
+    var rawBytes = this.str.getBytes(rowBytes);
     this.eof = !rawBytes.length;
     if (this.eof) {
       return;
@@ -720,8 +739,8 @@ var PredictorStream = (function PredictorStreamClosure() {
     var rowBytes = this.rowBytes;
     var pixBytes = this.pixBytes;
 
-    var predictor = this.stream.getByte();
-    var rawBytes = this.stream.getBytes(rowBytes);
+    var predictor = this.str.getByte();
+    var rawBytes = this.str.getBytes(rowBytes);
     this.eof = !rawBytes.length;
     if (this.eof) {
       return;