Rewrite clipboard write IPC handling to be easier to understand.

content/renderer/renderer_clipboard_client.cc

-// Copyright (c) 2012 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.
-
-// This file provides the embedder's side of the Clipboard interface.
-
-#include "content/renderer/renderer_clipboard_client.h"
-
-#include "base/memory/shared_memory.h"
-#include "base/numerics/safe_math.h"
-#include "base/strings/string16.h"
-#include "content/common/clipboard_messages.h"
-#include "content/public/renderer/content_renderer_client.h"
-#include "content/renderer/render_thread_impl.h"
-#include "content/renderer/scoped_clipboard_writer_glue.h"
-#include "ui/base/clipboard/clipboard.h"
-#include "ui/gfx/size.h"
-
-namespace content {
-
-namespace {
-
-class RendererClipboardWriteContext : public ClipboardClient::WriteContext {
- public:
-  RendererClipboardWriteContext();
-  ~RendererClipboardWriteContext() override;
-  void WriteBitmapFromPixels(ui::Clipboard::ObjectMap* objects,
-                             const void* pixels,
-                             const gfx::Size& size) override;
-  void Flush(const ui::Clipboard::ObjectMap& objects) override;
-
- private:
-  scoped_ptr<base::SharedMemory> shared_buf_;
-  DISALLOW_COPY_AND_ASSIGN(RendererClipboardWriteContext);
-};
-
-RendererClipboardWriteContext::RendererClipboardWriteContext() {
-}
-
-RendererClipboardWriteContext::~RendererClipboardWriteContext() {
-}
-
-// This definition of WriteBitmapFromPixels uses shared memory to communicate
-// across processes.
-void RendererClipboardWriteContext::WriteBitmapFromPixels(
-    ui::Clipboard::ObjectMap* objects,
-    const void* pixels,
-    const gfx::Size& size) {
-  // Do not try to write a bitmap more than once
-  if (shared_buf_)
-    return;
-
-  base::CheckedNumeric<uint32> checked_buf_size = 4;
-  checked_buf_size *= size.width();
-  checked_buf_size *= size.height();
-  if (!checked_buf_size.IsValid())
-    return;
-
-  uint32 buf_size = checked_buf_size.ValueOrDie();
-
-  // Allocate a shared memory buffer to hold the bitmap bits.
-  shared_buf_.reset(ChildThread::current()->AllocateSharedMemory(buf_size));
-  if (!shared_buf_)
-    return;
-
-  // Copy the bits into shared memory
-  DCHECK(shared_buf_->memory());
-  memcpy(shared_buf_->memory(), pixels, buf_size);
-  shared_buf_->Unmap();
-
-  ui::Clipboard::ObjectMapParam size_param;
-  const char* size_data = reinterpret_cast<const char*>(&size);
-  for (size_t i = 0; i < sizeof(gfx::Size); ++i)
-    size_param.push_back(size_data[i]);
-
-  ui::Clipboard::ObjectMapParams params;
-
-  // The first parameter is replaced on the receiving end with a pointer to
-  // a shared memory object containing the bitmap. We reserve space for it here.
-  ui::Clipboard::ObjectMapParam place_holder_param;
-  params.push_back(place_holder_param);
-  params.push_back(size_param);
-  (*objects)[ui::Clipboard::CBF_SMBITMAP] = params;
-}
-
-// Flushes the objects to the clipboard with an IPC.
-void RendererClipboardWriteContext::Flush(
-    const ui::Clipboard::ObjectMap& objects) {
-  if (shared_buf_) {
-    RenderThreadImpl::current()->Send(
-        new ClipboardHostMsg_WriteObjectsSync(objects, shared_buf_->handle()));
-  } else {
-    RenderThreadImpl::current()->Send(
-        new ClipboardHostMsg_WriteObjectsAsync(objects));
-  }
-}
-
-}  // anonymous namespace
-
-RendererClipboardClient::RendererClipboardClient() {
-}
-
-RendererClipboardClient::~RendererClipboardClient() {
-}
-
-ui::Clipboard* RendererClipboardClient::GetClipboard() {
-  return NULL;
-}
-
-uint64 RendererClipboardClient::GetSequenceNumber(ui::ClipboardType type) {
-  uint64 sequence_number = 0;
-  RenderThreadImpl::current()->Send(
-      new ClipboardHostMsg_GetSequenceNumber(type, &sequence_number));
-  return sequence_number;
-}
-
-bool RendererClipboardClient::IsFormatAvailable(content::ClipboardFormat format,
-                                                ui::ClipboardType type) {
-  bool result = false;
-  RenderThreadImpl::current()->Send(
-      new ClipboardHostMsg_IsFormatAvailable(format, type, &result));
-  return result;
-}
-
-void RendererClipboardClient::Clear(ui::ClipboardType type) {
-  RenderThreadImpl::current()->Send(new ClipboardHostMsg_Clear(type));
-}
-
-void RendererClipboardClient::ReadAvailableTypes(
-    ui::ClipboardType type,
-    std::vector<base::string16>* types,
-    bool* contains_filenames) {
-  RenderThreadImpl::current()->Send(new ClipboardHostMsg_ReadAvailableTypes(
-      type, types, contains_filenames));
-}
-
-void RendererClipboardClient::ReadText(ui::ClipboardType type,
-                                       base::string16* result) {
-  RenderThreadImpl::current()->Send(
-      new ClipboardHostMsg_ReadText(type, result));
-}
-
-void RendererClipboardClient::ReadHTML(ui::ClipboardType type,
-                                       base::string16* markup,
-                                       GURL* url, uint32* fragment_start,
-                                       uint32* fragment_end) {
-  RenderThreadImpl::current()->Send(new ClipboardHostMsg_ReadHTML(
-      type, markup, url, fragment_start, fragment_end));
-}
-
-void RendererClipboardClient::ReadRTF(ui::ClipboardType type,
-                                      std::string* result) {
-  RenderThreadImpl::current()->Send(new ClipboardHostMsg_ReadRTF(type, result));
-}
-
-void RendererClipboardClient::ReadImage(ui::ClipboardType type,
-                                        std::string* data) {
-  base::SharedMemoryHandle image_handle;
-  uint32 image_size = 0;
-  RenderThreadImpl::current()->Send(
-      new ClipboardHostMsg_ReadImage(type, &image_handle, &image_size));
-  if (base::SharedMemory::IsHandleValid(image_handle)) {
-    base::SharedMemory buffer(image_handle, true);
-    buffer.Map(image_size);
-    data->append(static_cast<char*>(buffer.memory()), image_size);
-  }
-}
-
-void RendererClipboardClient::ReadCustomData(ui::ClipboardType clipboard_type,
-                                             const base::string16& type,
-                                             base::string16* data) {
-  RenderThreadImpl::current()->Send(
-      new ClipboardHostMsg_ReadCustomData(clipboard_type, type, data));
-}
-
-ClipboardClient::WriteContext* RendererClipboardClient::CreateWriteContext() {
-  return new RendererClipboardWriteContext;
-}
-
-}  // namespace content