Bitmap transport

chrome/common/transport_dib_win.cc

+// Copyright (c) 2009 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 <limits>
+#include <windows.h>
+
+#include "base/logging.h"
+#include "base/sys_info.h"
+#include "chrome/common/transport_dib.h"
+
+TransportDIB::TransportDIB() {
+}
+
+TransportDIB::~TransportDIB() {
+}
+
+TransportDIB::TransportDIB(HANDLE handle)
+    : shared_memory_(handle, false /* read write */) {
+}
+
+// static
+TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
+  size_t allocation_granularity = base::SysInfo::VMAllocationGranularity();
+  size = size / allocation_granularity + 1;
+  size = size * allocation_granularity;
+
+  TransportDIB* dib = new TransportDIB;
+
+  if (!dib->shared_memory_.Create(L"", false /* read write */,
+                                  true /* open existing */, size)) {
+    delete dib;
+    return NULL;
+  }
+
+  dib->size_ = size;
+  dib->sequence_num_ = sequence_num;
+
+  return dib;
+}
+
+// static
+TransportDIB* TransportDIB::Map(TransportDIB::Handle handle) {
+  TransportDIB* dib = new TransportDIB(handle);
+  if (!dib->shared_memory_.Map(0 /* map whole shared memory segment */)) {
+    DLOG(ERROR) << "Failed to map transport DIB"
+                << " handle:" << handle
+                << " error:" << GetLastError();
+    delete dib;
+    return NULL;
+  }
+
+  // There doesn't seem to be any way to find the size of the shared memory
+  // region! GetFileSize indicates that the handle is invalid. Thus, we
+  // conservatively set the size to the maximum and hope that the renderer
+  // isn't about to ask us to read off the end of the array.
+  dib->size_ = std::numeric_limits<size_t>::max();
+
+  return dib;
+}
+
+void* TransportDIB::memory() const {
+  return shared_memory_.memory();
+}
+
+TransportDIB::Handle TransportDIB::handle() const {
+  return shared_memory_.handle();
+}
+
+TransportDIB::Id TransportDIB::id() const {
+  return Id(shared_memory_.handle(), sequence_num_);
+}