Merge pull request #4809 from Snuffleupagus/bug-866395-redux

Fix loading of fonts with empty font files (bug 866395 and issue 3522)

src/core/chunked_stream.js

@@ -133,6 +133,10 @@ var ChunkedStream = (function ChunkedStreamClosure() {
       return this.end - this.start;
     },
 
+    get isEmpty() {
+      return this.length === 0;
+    },
+
     getByte: function ChunkedStream_getByte() {
       var pos = this.pos;
       if (pos >= this.end) {

src/core/fonts.js

@@ -2204,7 +2204,13 @@ var Font = (function FontClosure() {
       this.defaultVMetrics = properties.defaultVMetrics;
     }
 
-    if (!file) {
+    if (!file || file.isEmpty) {
+      if (file) {
+        // Some bad PDF generators will include empty font files,
+        // attempting to recover by assuming that no file exists.
+        warn('Font file is empty in "' + name + '" (' + this.loadedName + ')');
+      }
+
       this.missingFile = true;
       // The file data is not specified. Trying to fix the font name
       // to be used with the canvas.font.

src/core/stream.js

@@ -35,6 +35,9 @@ var Stream = (function StreamClosure() {
     get length() {
       return this.end - this.start;
     },
+    get isEmpty() {
+      return this.length === 0;
+    },
     getByte: function Stream_getByte() {
       if (this.pos >= this.end) {
         return -1;
@@ -128,6 +131,12 @@ var DecodeStream = (function DecodeStreamClosure() {
   }
 
   DecodeStream.prototype = {
+    get isEmpty() {
+      while (!this.eof && this.bufferLength === 0) {
+        this.readBlock();
+      }
+      return this.bufferLength === 0;
+    },
     ensureBuffer: function DecodeStream_ensureBuffer(requested) {
       var buffer = this.buffer;
       var current;
@@ -213,7 +222,7 @@ var DecodeStream = (function DecodeStreamClosure() {
       }
       return new Stream(this.buffer, start, length, dict);
     },
-    skip: function Stream_skip(n) {
+    skip: function DecodeStream_skip(n) {
       if (!n) {
         n = 1;
       }

test/pdfs/.gitignore

@@ -55,6 +55,7 @@
 !gradientfill.pdf
 !bug903856.pdf
 !bug850854.pdf
+!bug866395.pdf
 !basicapi.pdf
 !mixedfonts.pdf
 !shading_extend.pdf

test/test_manifest.json

@@ -682,6 +682,14 @@
        "type": "eq",
        "about": "Seac with differences array that messes up mapping."
     },
+    {  "id": "bug866395",
+       "file": "pdfs/bug866395.pdf",
+       "md5": "f03bc77e84637241980b09a0a220f575",
+       "link": false,
+       "rounds": 1,
+       "type": "eq",
+       "about": "Font with an empty font file."
+    },
     {  "id": "ocs",
       "file": "pdfs/ocs.pdf",
       "md5": "2ade57e954ae7632749cf328daeaa7a8",