ui/surface/transport_dib_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/surface/transport_dib.h"
   6
   7 #include <windows.h>
   8
   9 #include <limits>
  10
  11 #include "base/logging.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/sys_info.h"
  14 #include "skia/ext/platform_canvas.h"
  15
  16 TransportDIB::TransportDIB()
  17     : size_(0) {
  18 }
  19
  20 TransportDIB::~TransportDIB() {
  21 }
  22
  23 TransportDIB::TransportDIB(HANDLE handle)
  24     : shared_memory_(handle, false /* read write */),
  25       size_(0) {
  26 }
  27
  28 // static
  29 TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
  30   TransportDIB* dib = new TransportDIB;
  31
  32   if (!dib->shared_memory_.CreateAnonymous(size)) {
  33     delete dib;
  34     return NULL;
  35   }
  36
  37   dib->size_ = size;
  38   dib->sequence_num_ = sequence_num;
  39
  40   return dib;
  41 }
  42
  43 // static
  44 TransportDIB* TransportDIB::Map(Handle handle) {
  45   scoped_ptr<TransportDIB> dib(CreateWithHandle(handle));
  46   if (!dib->Map())
  47     return NULL;
  48   return dib.release();
  49 }
  50
  51 // static
  52 TransportDIB* TransportDIB::CreateWithHandle(Handle handle) {
  53   return new TransportDIB(handle);
  54 }
  55
  56 // static
  57 bool TransportDIB::is_valid_handle(Handle dib) {
  58   return dib != NULL;
  59 }
  60
  61 skia::PlatformCanvas* TransportDIB::GetPlatformCanvas(int w, int h) {
  62   // This DIB already mapped the file into this process, but PlatformCanvas
  63   // will map it again.
  64   DCHECK(!memory()) << "Mapped file twice in the same process.";
  65
  66   // We can't check the canvas size before mapping, but it's safe because
  67   // Windows will fail to map the section if the dimensions of the canvas
  68   // are too large.
  69   skia::PlatformCanvas* canvas =
  70       skia::CreatePlatformCanvas(w, h, true, shared_memory_.handle(),
  71                                  skia::RETURN_NULL_ON_FAILURE);
  72
  73   // Calculate the size for the memory region backing the canvas.
  74   if (canvas)
  75     size_ = skia::PlatformCanvasStrideForWidth(w) * h;
  76
  77   return canvas;
  78 }
  79
  80 bool TransportDIB::Map() {
  81   if (!is_valid_handle(shared_memory_.handle()))
  82     return false;
  83   if (memory())
  84     return true;
  85
  86   if (!shared_memory_.Map(0 /* map whole shared memory segment */)) {
  87     LOG(ERROR) << "Failed to map transport DIB"
  88                << " handle:" << shared_memory_.handle()
  89                << " error:" << ::GetLastError();
  90     return false;
  91   }
  92
  93   size_ = shared_memory_.mapped_size();
  94   return true;
  95 }
  96
  97 void* TransportDIB::memory() const {
  98   return shared_memory_.memory();
  99 }