From 69a97bcba7637967e05547f2a2803463637ddfef Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 8 Oct 2021 12:21:26 +0200
Subject: [PATCH] Take the /CIDToGIDMap data into account when computing the
 hash, in `PartialEvaluator.preEvaluateFont`, for composite fonts (bug
 1734802)

This is unfortunately *yet another* bug in the `preEvaluateFont`-implementation, and I've lost count of the number of times I've had to tweak this code over the years :-(
I really cannot help thinking that PR 4423 was way too simplistic, since it missed a bunch of cases that leads to broken font rendering in many PDF documents.

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1734802
---
 src/core/evaluator.js         | 13 ++++++++++++-
 test/pdfs/bug1734802.pdf.link |  1 +
 test/test_manifest.json       |  8 ++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 test/pdfs/bug1734802.pdf.link

diff --git a/src/core/evaluator.js b/src/core/evaluator.js
index dbf66f45e..2cefb5560 100644
--- a/src/core/evaluator.js
+++ b/src/core/evaluator.js
@@ -81,6 +81,7 @@ import {
   LocalTilingPatternCache,
 } from "./image_utils.js";
 import { NullStream, Stream } from "./stream.js";
+import { BaseStream } from "./base_stream.js";
 import { bidi } from "./bidi.js";
 import { ColorSpace } from "./colorspace.js";
 import { DecodeStream } from "./decode_stream.js";
@@ -3139,7 +3140,7 @@ class PartialEvaluator {
       }
 
       const cidToGidMap = dict.get("CIDToGIDMap");
-      if (isStream(cidToGidMap)) {
+      if (cidToGidMap instanceof BaseStream) {
         cidToGidBytes = cidToGidMap.getBytes();
       }
     }
@@ -3790,6 +3791,16 @@ class PartialEvaluator {
           }
           hash.update(widthsBuf.join());
         }
+
+        const cidToGidMap =
+          dict.getRaw("CIDToGIDMap") || baseDict.getRaw("CIDToGIDMap");
+        if (cidToGidMap instanceof Name) {
+          hash.update(cidToGidMap.name);
+        } else if (cidToGidMap instanceof Ref) {
+          hash.update(cidToGidMap.toString());
+        } else if (cidToGidMap instanceof BaseStream) {
+          hash.update(cidToGidMap.peekBytes());
+        }
       }
     }
 
diff --git a/test/pdfs/bug1734802.pdf.link b/test/pdfs/bug1734802.pdf.link
new file mode 100644
index 000000000..25660d735
--- /dev/null
+++ b/test/pdfs/bug1734802.pdf.link
@@ -0,0 +1 @@
+https://bugzilla.mozilla.org/attachment.cgi?id=9244936
diff --git a/test/test_manifest.json b/test/test_manifest.json
index 016d55262..03a641bd1 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -166,6 +166,14 @@
        "rounds": 1,
        "type": "eq"
     },
+    {  "id": "bug1734802",
+       "file": "pdfs/bug1734802.pdf",
+       "md5": "a23ad8af95ffca3876e110a5f4dec9bc",
+       "rounds": 1,
+       "link": true,
+       "lastPage": 3,
+       "type": "eq"
+    },
     {  "id": "bug921760",
        "file": "pdfs/bug921760.pdf",
        "md5": "1aa136d786a65b0d7cce7bdb3c58c6c3",