From 388851e37b0492442a95d0dcdfde545bb2bcbf75 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sun, 13 Aug 2017 17:11:49 +0200
Subject: [PATCH] Add a `isDestsEqual` helper function, to allow comparing
 explicit destinations, in `pdf_history.js`

---
 test/unit/clitests.json       |  1 +
 test/unit/jasmine-boot.js     |  1 +
 test/unit/pdf_history_spec.js | 45 +++++++++++++++++++++++++++++++++++
 web/pdf_history.js            | 37 ++++++++++++++++++++++++++++
 4 files changed, 84 insertions(+)
 create mode 100644 test/unit/pdf_history_spec.js

diff --git a/test/unit/clitests.json b/test/unit/clitests.json
index 3c98a6f0a..46b115ada 100644
--- a/test/unit/clitests.json
+++ b/test/unit/clitests.json
@@ -17,6 +17,7 @@
     "murmurhash3_spec.js",
     "node_stream_spec.js",
     "parser_spec.js",
+    "pdf_history.js",
     "primitives_spec.js",
     "stream_spec.js",
     "type1_parser_spec.js",
diff --git a/test/unit/jasmine-boot.js b/test/unit/jasmine-boot.js
index 7dfa7321d..1405f9990 100644
--- a/test/unit/jasmine-boot.js
+++ b/test/unit/jasmine-boot.js
@@ -64,6 +64,7 @@ function initializePDFJS(callback) {
     'pdfjs-test/unit/murmurhash3_spec',
     'pdfjs-test/unit/network_spec',
     'pdfjs-test/unit/parser_spec',
+    'pdfjs-test/unit/pdf_history_spec',
     'pdfjs-test/unit/primitives_spec',
     'pdfjs-test/unit/stream_spec',
     'pdfjs-test/unit/type1_parser_spec',
diff --git a/test/unit/pdf_history_spec.js b/test/unit/pdf_history_spec.js
new file mode 100644
index 000000000..1b2930e18
--- /dev/null
+++ b/test/unit/pdf_history_spec.js
@@ -0,0 +1,45 @@
+/* Copyright 2017 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { isDestsEqual } from '../../web/pdf_history';
+
+describe('pdf_history', function() {
+  describe('isDestsEqual', function() {
+    let firstDest = [{ num: 1, gen: 0, }, { name: 'XYZ', }, 0, 375, null];
+    let secondDest = [{ num: 5, gen: 0, }, { name: 'XYZ', }, 0, 375, null];
+    let thirdDest = [{ num: 1, gen: 0, }, { name: 'XYZ', }, 750, 0, null];
+    let fourthDest = [{ num: 1, gen: 0, }, { name: 'XYZ', }, 0, 375, 1.0];
+    let fifthDest = [{ gen: 0, num: 1, }, { name: 'XYZ', }, 0, 375, null];
+
+    it('should reject non-equal destination arrays', function() {
+      expect(isDestsEqual(firstDest, undefined)).toEqual(false);
+      expect(isDestsEqual(firstDest, [1, 2, 3, 4, 5])).toEqual(false);
+
+      expect(isDestsEqual(firstDest, secondDest)).toEqual(false);
+      expect(isDestsEqual(firstDest, thirdDest)).toEqual(false);
+      expect(isDestsEqual(firstDest, fourthDest)).toEqual(false);
+    });
+
+    it('should accept equal destination arrays', function() {
+      expect(isDestsEqual(firstDest, firstDest)).toEqual(true);
+      expect(isDestsEqual(firstDest, fifthDest)).toEqual(true);
+
+      let firstDestCopy = firstDest.slice();
+      expect(firstDest).not.toBe(firstDestCopy);
+
+      expect(isDestsEqual(firstDest, firstDestCopy)).toEqual(true);
+    });
+  });
+});
diff --git a/web/pdf_history.js b/web/pdf_history.js
index e4dd680a0..ef1a7b33a 100644
--- a/web/pdf_history.js
+++ b/web/pdf_history.js
@@ -30,6 +30,43 @@ class PDFHistory {
   forward() {}
 }
 
+function isDestsEqual(firstDest, secondDest) {
+  function isEntryEqual(first, second) {
+    if (typeof first !== typeof second) {
+      return false;
+    }
+    if (first instanceof Array || second instanceof Array) {
+      return false;
+    }
+    if (first !== null && typeof first === 'object' && second !== null) {
+      if (Object.keys(first).length !== Object.keys(second).length) {
+        return false;
+      }
+      for (var key in first) {
+        if (!isEntryEqual(first[key], second[key])) {
+          return false;
+        }
+      }
+      return true;
+    }
+    return first === second || (Number.isNaN(first) && Number.isNaN(second));
+  }
+
+  if (!(firstDest instanceof Array && secondDest instanceof Array)) {
+    return false;
+  }
+  if (firstDest.length !== secondDest.length) {
+    return false;
+  }
+  for (let i = 0, ii = firstDest.length; i < ii; i++) {
+    if (!isEntryEqual(firstDest[i], secondDest[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
 export {
   PDFHistory,
+  isDestsEqual,
 };