blob: 827fcffbc976eb9fe65f0fc804d375ca0db67528 [file] [log] [blame]
// Copyright (c) 2013 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 "ui/surface/transport_dib.h"
#include <stddef.h>
#include <memory>
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/memory/shared_memory_mapping.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "base/numerics/checked_math.h"
#include "build/build_config.h"
#include "skia/ext/platform_canvas.h"
TransportDIB::TransportDIB(base::UnsafeSharedMemoryRegion region)
: shm_region_(std::move(region)) {}
TransportDIB::~TransportDIB() = default;
// static
std::unique_ptr<TransportDIB> TransportDIB::Map(
base::UnsafeSharedMemoryRegion region) {
std::unique_ptr<TransportDIB> dib = CreateWithHandle(std::move(region));
if (!dib->Map())
return nullptr;
return dib;
// static
std::unique_ptr<TransportDIB> TransportDIB::CreateWithHandle(
base::UnsafeSharedMemoryRegion region) {
return base::WrapUnique(new TransportDIB(std::move(region)));
std::unique_ptr<SkCanvas> TransportDIB::GetPlatformCanvas(int w,
int h,
bool opaque) {
if (!shm_region_.IsValid())
return nullptr;
#if defined(OS_WIN)
// This DIB already mapped the file into this process, but PlatformCanvas
// will map it again.
DCHECK(!memory()) << "Mapped file twice in the same process.";
// We can't check the canvas size before mapping, but it's safe because
// Windows will fail to map the section if the dimensions of the canvas
// are too large.
std::unique_ptr<SkCanvas> canvas =
w, h, opaque, shm_region_.GetPlatformHandle(),
// Calculate the size for the memory region backing the canvas.
if (canvas)
size_ = skia::PlatformCanvasStrideForWidth(w) * h;
return canvas;
if ((!memory() && !Map()) || !VerifyCanvasSize(w, h))
return nullptr;
return skia::CreatePlatformCanvasWithPixels(w, h, opaque,
bool TransportDIB::Map() {
if (!shm_region_.IsValid())
return false;
if (memory())
return true;
shm_mapping_ = shm_region_.Map();
if (!shm_mapping_.IsValid()) {
PLOG(ERROR) << "Failed to map transport DIB";
return false;
size_ = shm_mapping_.size();
return true;
void* TransportDIB::memory() const {
return shm_mapping_.IsValid() ? shm_mapping_.memory() : nullptr;
base::UnsafeSharedMemoryRegion* TransportDIB::shared_memory_region() {
return &shm_region_;
// static
bool TransportDIB::VerifyCanvasSize(int w, int h) {
if (w <= 0 || h <= 0)
return false;
const size_t stride = skia::PlatformCanvasStrideForWidth(w);
size_t canvas_size;
if (!base::CheckMul(h, stride).AssignIfValid(&canvas_size))
return false;
return canvas_size <= size_;