commit edbc66c0f3b9e4e693714cf9037bb2f1b7829a0a
author pkotwicz@chromium.org <pkotwicz@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98> Tue Jan 15 03:59:55 2013 +0900
committer Qijiang Fan <fqj@google.com> Thu Jun 04 13:55:26 2020 +0900
tree 279fd9783acac0b6e8a90362ea64c59e8a22fa7e
parent 13a55bc43d9d5803aa2643dbb0507adb8ed87e32

Avoid sending notifications when the bitmap data in the history backend is replaced with bitmap data which is byte for byte equal.

Bug=168223
Test=HistoryBackendTest.*
     Manual: see comment #7 in bug

Review URL: https://chromiumcodereview.appspot.com/11830007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176691 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 5565316246b58c1168fb10e9439fc903ebb8faa6

base/memory/ref_counted_memory.cc

diff --git a/base/memory/ref_counted_memory.cc b/base/memory/ref_counted_memory.cc
index 9bcde32..b048a6e 100644
--- a/base/memory/ref_counted_memory.cc
+++ b/base/memory/ref_counted_memory.cc
@@ -8,6 +8,13 @@
 
 namespace base {
 
+bool RefCountedMemory::Equals(
+    const scoped_refptr<RefCountedMemory>& other) const {
+  return other.get() &&
+         size() == other->size() &&
+         (memcmp(front(), other->front(), size()) == 0);
+}
+
 RefCountedMemory::RefCountedMemory() {}
 
 RefCountedMemory::~RefCountedMemory() {}

base/memory/ref_counted_memory.h

diff --git a/base/memory/ref_counted_memory.h b/base/memory/ref_counted_memory.h
index 9edcd6f..b99871b 100644
--- a/base/memory/ref_counted_memory.h
+++ b/base/memory/ref_counted_memory.h
@@ -27,6 +27,9 @@
   // Size of the memory pointed to.
   virtual size_t size() const = 0;
 
+  // Returns true if |other| is byte for byte equal.
+  bool Equals(const scoped_refptr<RefCountedMemory>& other) const;
+
  protected:
   friend class base::RefCountedThreadSafe<RefCountedMemory>;
   RefCountedMemory();

base/memory/ref_counted_memory_unittest.cc

diff --git a/base/memory/ref_counted_memory_unittest.cc b/base/memory/ref_counted_memory_unittest.cc
index 1936040..c6f2b9c 100644
--- a/base/memory/ref_counted_memory_unittest.cc
+++ b/base/memory/ref_counted_memory_unittest.cc
@@ -42,4 +42,30 @@
   EXPECT_EQ('e', mem->front()[1]);
 }
 
+TEST(RefCountedMemoryUnitTest, Equals) {
+  std::string s1("same");
+  scoped_refptr<RefCountedMemory> mem1 = RefCountedString::TakeString(&s1);
+
+  std::vector<unsigned char> d2;
+  d2.push_back('s');
+  d2.push_back('a');
+  d2.push_back('m');
+  d2.push_back('e');
+  scoped_refptr<RefCountedMemory> mem2 = RefCountedBytes::TakeVector(&d2);
+
+  EXPECT_TRUE(mem1->Equals(mem2));
+
+  std::string s3("diff");
+  scoped_refptr<RefCountedMemory> mem3 = RefCountedString::TakeString(&s3);
+
+  EXPECT_FALSE(mem1->Equals(mem3));
+  EXPECT_FALSE(mem2->Equals(mem3));
+}
+
+TEST(RefCountedMemoryUnitTest, EqualsNull) {
+  std::string s("str");
+  scoped_refptr<RefCountedMemory> mem = RefCountedString::TakeString(&s);
+  EXPECT_FALSE(mem->Equals(NULL));
+}
+
 }  //  namespace base