Rewrite clipboard write IPC handling to be easier to understand.

content/browser/renderer_host/clipboard_message_filter_unittest.cc

Index: content/browser/renderer_host/clipboard_message_filter_unittest.cc
diff --git a/content/browser/renderer_host/clipboard_message_filter_unittest.cc b/content/browser/renderer_host/clipboard_message_filter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..dda1c825fe42fdbdb8afc47ae1ef85b9e07fc790
--- /dev/null
+++ b/content/browser/renderer_host/clipboard_message_filter_unittest.cc
@@ -0,0 +1,142 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/clipboard_message_filter.h"
+
+#include <string.h>
+
+#include "base/memory/ref_counted.h"
+#include "base/process/process_handle.h"
+#include "base/run_loop.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/base/clipboard/clipboard.h"
+#include "ui/gfx/size.h"
+
+#if defined(USE_X11)
+#include "ui/events/platform/platform_event_source.h"
+#endif
+
+namespace content {
+
+class ClipboardMessageFilterTest : public ::testing::Test {
+ protected:
+  ClipboardMessageFilterTest()
+      : filter_(new ClipboardMessageFilter),
+#if defined(USE_X11)
+        event_source_(ui::PlatformEventSource::CreateDefault()),
+#endif
+        clipboard_(ui::Clipboard::GetForCurrentThread()) {
+    filter_->set_peer_pid_for_testing(base::GetCurrentProcId());
+  }
+
+  virtual ~ClipboardMessageFilterTest() override {
+    ui::Clipboard::DestroyClipboardForCurrentThread();
+  }
+
+  scoped_ptr<base::SharedMemory> CreateAndMapReadOnlySharedMemory(size_t size) {
+    scoped_ptr<base::SharedMemory> m = CreateReadOnlySharedMemory(size);
+    if (!m->Map(size))
+      return nullptr;
+    return m.Pass();
+  }
+
+  scoped_ptr<base::SharedMemory> CreateReadOnlySharedMemory(size_t size) {
+    auto m = make_scoped_ptr(new base::SharedMemory());

[Will Harris, 2014/10/06 22:49:24]

feels weird to see auto

[dcheng, 2014/10/06 22:51:44]

Hmm. I guess. Basically, scoped_ptr<base::SharedMemory> m = make_scoped_ptr(new
base::SharedMemory); feels really redundant to me. Since it's clear what the
type is, I think it's OK to omit it here. There are several other locations
(e.g. line 40) where I opted not to use auto, because it's not 100% clear.

[jamesr, 2014/10/06 23:00:27]

Comparing the two:

auto m = make_scoped_ptr(new base::SharedMemory());
scoped_ptr<base::SharedMemory> m(new base::SharedMemory);

the latter is 6 characters longer but feels pretty tight to me and is clearer. 
I'd skip the auto here.

[dcheng, 2014/10/06 23:34:41]

Done.

+    base::SharedMemoryCreateOptions options;
+    options.size = size;
+    options.share_read_only = true;
+    if (!m->Create(options))
+      return nullptr;
+    return m.Pass();
+  }
+
+  void CallWriteImage(const gfx::Size& size,
+                      base::SharedMemory* shared_memory) {
+    base::SharedMemoryHandle handle;
+    ASSERT_TRUE(shared_memory->GiveReadOnlyToProcess(
+        base::GetCurrentProcessHandle(), &handle));
+    CallWriteImageDirectly(size, handle);
+  }
+
+  // Prefer to use CallWriteImage() in tests.
+  void CallWriteImageDirectly(const gfx::Size& size,
+                              base::SharedMemoryHandle handle) {
+    filter_->OnWriteImage(ui::CLIPBOARD_TYPE_COPY_PASTE, size, handle);
+  }
+
+  void CallCommitWrite() {
+    filter_->OnCommitWrite(ui::CLIPBOARD_TYPE_COPY_PASTE);
+    base::RunLoop().RunUntilIdle();
+  }
+
+  ui::Clipboard* clipboard() { return clipboard_; }
+
+ private:
+  const TestBrowserThreadBundle thread_bundle_;
+  const scoped_refptr<ClipboardMessageFilter> filter_;
+#if defined(USE_X11)
+  const scoped_ptr<ui::PlatformEventSource> event_source_;
+#endif
+  ui::Clipboard* const clipboard_;
+};
+
+// Test that it actually works.
+TEST_F(ClipboardMessageFilterTest, SimpleImage) {
+  static const uint32_t bitmap_data[] = {
+      0x33333333, 0xdddddddd, 0xeeeeeeee, 0x00000000,
+      0x88888888, 0x66666666, 0x55555555, 0xbbbbbbbb,
+      0x44444444, 0xaaaaaaaa, 0x99999999, 0x77777777,
+      0xffffffff, 0x11111111, 0x22222222, 0xcccccccc,
+  };
+
+  scoped_ptr<base::SharedMemory> shared_memory =
+      CreateAndMapReadOnlySharedMemory(sizeof(bitmap_data));
+  memcpy(shared_memory->memory(), bitmap_data, sizeof(bitmap_data));
+
+  CallWriteImage(gfx::Size(4, 4), shared_memory.get());
+  uint64_t sequence_number =
+      clipboard()->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE);
+  CallCommitWrite();
+
+  EXPECT_NE(sequence_number,
+            clipboard()->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE));
+  EXPECT_FALSE(clipboard()->IsFormatAvailable(
+      ui::Clipboard::GetPlainTextFormatType(), ui::CLIPBOARD_TYPE_COPY_PASTE));
+  EXPECT_TRUE(clipboard()->IsFormatAvailable(
+      ui::Clipboard::GetBitmapFormatType(), ui::CLIPBOARD_TYPE_COPY_PASTE));
+
+  SkBitmap actual = clipboard()->ReadImage(ui::CLIPBOARD_TYPE_COPY_PASTE);
+  SkAutoLockPixels locked(actual);
+  EXPECT_EQ(sizeof(bitmap_data), actual.getSize());
+  EXPECT_EQ(0,
+            memcmp(bitmap_data, actual.getAddr32(0, 0), sizeof(bitmap_data)));
+}
+
+// Test with a size that would overflow a naive 32-bit row bytes calculation.
+TEST_F(ClipboardMessageFilterTest, ImageSizeOverflows32BitRowBytes) {
+  scoped_ptr<base::SharedMemory> shared_memory =
+      CreateReadOnlySharedMemory(0x20000000);
+
+  CallWriteImage(gfx::Size(0x20000000, 1), shared_memory.get());
+  uint64_t sequence_number =
+      clipboard()->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE);
+  CallCommitWrite();
+
+  EXPECT_EQ(sequence_number,
+            clipboard()->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE));
+}
+
+TEST_F(ClipboardMessageFilterTest, InvalidSharedMemoryHandle) {
+  CallWriteImageDirectly(gfx::Size(5, 5), base::SharedMemory::NULLHandle());
+  uint64_t sequence_number =
+      clipboard()->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE);
+  CallCommitWrite();
+
+  EXPECT_EQ(sequence_number,
+            clipboard()->GetSequenceNumber(ui::CLIPBOARD_TYPE_COPY_PASTE));
+}
+
+}  // namespace content