mojo: Don't leak handles when assigning to ScopedHandles.

BUG=374520

Review URL: https://codereview.chromium.org/336313003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278015 0039d316-1c4b-4281-b951-d872f2087c98

mojo/public/cpp/system/core.h

@@ -107,7 +107,10 @@ class ScopedHandleBase {
   // Move-only constructor and operator=.
   ScopedHandleBase(RValue other) : handle_(other.object->release()) {}
   ScopedHandleBase& operator=(RValue other) {
-    handle_ = other.object->release();
+    if (other.object != this) {
+      CloseIfNecessary();
+      handle_ = other.object->release();
+    }
     return *this;
   }
 

mojo/public/cpp/system/tests/core_unittest.cc

@@ -386,6 +386,33 @@ TEST(CoreCppTest, TearDownWithMessagesEnqueued) {
   }
 }
 
+TEST(CoreCppTest, ScopedHandleMoveCtor) {
+  ScopedSharedBufferHandle buffer1;
+  EXPECT_EQ(MOJO_RESULT_OK, CreateSharedBuffer(NULL, 1024, &buffer1));
+  EXPECT_TRUE(buffer1.is_valid());
+
+  ScopedSharedBufferHandle buffer2;
+  EXPECT_EQ(MOJO_RESULT_OK, CreateSharedBuffer(NULL, 1024, &buffer2));
+  EXPECT_TRUE(buffer2.is_valid());
+
+  // If this fails to close buffer1, ScopedHandleBase::CloseIfNecessary() will
+  // assert.
+  buffer1 = buffer2.Pass();
+
+  EXPECT_TRUE(buffer1.is_valid());
+  EXPECT_FALSE(buffer2.is_valid());
+}
+
+TEST(CoreCppTest, ScopedHandleMoveCtorSelf) {
+  ScopedSharedBufferHandle buffer1;
+  EXPECT_EQ(MOJO_RESULT_OK, CreateSharedBuffer(NULL, 1024, &buffer1));
+  EXPECT_TRUE(buffer1.is_valid());
+
+  buffer1 = buffer1.Pass();
+
+  EXPECT_TRUE(buffer1.is_valid());
+}
+
 // TODO(vtl): Write data pipe tests.
 
 }  // namespace