Slightly refactor the fontRef handling in PartialEvaluator_loadFont (issue 7403 and issue 7402)

src/core/evaluator.js

@@ -662,8 +662,8 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         return errorFont();
       }
 
-      // We are holding font.translated references just for fontRef that are not
-      // dictionaries (Dict). See explanation below.
+      // We are holding `font.translated` references just for `fontRef`s that
+      // are not actually `Ref`s, but rather `Dict`s. See explanation below.
       if (font.translated) {
         return font.translated;
       }
@@ -672,7 +672,12 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
       var preEvaluatedFont = this.preEvaluateFont(font, xref);
       var descriptor = preEvaluatedFont.descriptor;
-      var fontID = fontRef.num + '_' + fontRef.gen;
+
+      var fontRefIsRef = isRef(fontRef), fontID;
+      if (fontRefIsRef) {
+        fontID = fontRef.toString();
+      }
+
       if (isDict(descriptor)) {
         if (!descriptor.fontAliases) {
           descriptor.fontAliases = Object.create(null);
@@ -682,36 +687,53 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         var hash = preEvaluatedFont.hash;
         if (fontAliases[hash]) {
           var aliasFontRef = fontAliases[hash].aliasRef;
-          if (aliasFontRef && this.fontCache.has(aliasFontRef)) {
+          if (fontRefIsRef && aliasFontRef &&
+              this.fontCache.has(aliasFontRef)) {
             this.fontCache.putAlias(fontRef, aliasFontRef);
             return this.fontCache.get(fontRef);
           }
-        }
-
-        if (!fontAliases[hash]) {
+        } else {
           fontAliases[hash] = {
             fontID: Font.getFontID()
           };
         }
 
-        fontAliases[hash].aliasRef = fontRef;
+        if (fontRefIsRef) {
+          fontAliases[hash].aliasRef = fontRef;
+        }
         fontID = fontAliases[hash].fontID;
       }
 
-      // Workaround for bad PDF generators that don't reference fonts
-      // properly, i.e. by not using an object identifier.
-      // Check if the fontRef is a Dict (as opposed to a standard object),
-      // in which case we don't cache the font and instead reference it by
-      // fontName in font.loadedName below.
-      var fontRefIsDict = isDict(fontRef);
-      if (!fontRefIsDict) {
+      // Workaround for bad PDF generators that reference fonts incorrectly,
+      // where `fontRef` is a `Dict` rather than a `Ref` (fixes bug946506.pdf).
+      // In this case we should not put the font into `this.fontCache` (which is
+      // a `RefSetCache`), since it's not meaningful to use a `Dict` as a key.
+      //
+      // However, if we don't cache the font it's not possible to remove it
+      // when `cleanup` is triggered from the API, which causes issues on
+      // subsequent rendering operations (see issue7403.pdf).
+      // A simple workaround would be to just not hold `font.translated`
+      // references in this case, but this would force us to unnecessarily load
+      // the same fonts over and over.
+      //
+      // Instead, we cheat a bit by attempting to use a modified `fontID` as a
+      // key in `this.fontCache`, to allow the font to be cached.
+      // NOTE: This works because `RefSetCache` calls `toString()` on provided
+      //       keys. Also, since `fontRef` is used when getting cached fonts,
+      //       we'll not accidentally match fonts cached with the `fontID`.
+      if (fontRefIsRef) {
         this.fontCache.put(fontRef, fontCapability.promise);
+      } else {
+        if (!fontID) {
+          fontID = (this.uniquePrefix || 'F_') + (++this.idCounters.obj);
+        }
+        this.fontCache.put('id_' + fontID, fontCapability.promise);
       }
+      assert(fontID, 'The "fontID" must be defined.');
 
       // Keep track of each font we translated so the caller can
       // load them asynchronously before calling display on a page.
-      font.loadedName = 'g_' + this.pdfManager.docId + '_f' + (fontRefIsDict ?
-        fontName.replace(/\W/g, '') : fontID);
+      font.loadedName = 'g_' + this.pdfManager.docId + '_f' + fontID;
 
       font.translated = fontCapability.promise;
 
@@ -2115,15 +2137,15 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         if (isName(encoding)) {
           hash.update(encoding.name);
         } else if (isRef(encoding)) {
-          hash.update(encoding.num + '_' + encoding.gen);
+          hash.update(encoding.toString());
         } else if (isDict(encoding)) {
           var keys = encoding.getKeys();
           for (var i = 0, ii = keys.length; i < ii; i++) {
             var entry = encoding.getRaw(keys[i]);
             if (isName(entry)) {
               hash.update(entry.name);
             } else if (isRef(entry)) {
-              hash.update(entry.num + '_' + entry.gen);
+              hash.update(entry.toString());
             } else if (isArray(entry)) { // 'Differences' entry.
               // Ideally we should check the contents of the array, but to avoid
               // parsing it here and then again in |extractDataStructures|,

test/pdfs/.gitignore

@@ -27,6 +27,7 @@
 !issue7180.pdf
 !issue7200.pdf
 !issue7229.pdf
+!issue7403.pdf
 !issue7426.pdf
 !issue7439.pdf
 !issue7492.pdf

test/test_manifest.json

@@ -962,6 +962,13 @@
        "rounds": 1,
        "type": "eq"
     },
+    {  "id": "issue7403",
+       "file": "pdfs/issue7403.pdf",
+       "md5": "0f7bb6b3c58e33bbf76ce5161cd665c3",
+       "link": false,
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "protectip",
        "file": "pdfs/protectip.pdf",
        "md5": "676e7a7b8f96d04825361832b1838a93",