michael@0: // Copyright (c) 2009 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include <limits>
michael@0: #include <windows.h>
michael@0: 
michael@0: #include "base/logging.h"
michael@0: #include "base/sys_info.h"
michael@0: #include "chrome/common/transport_dib.h"
michael@0: 
michael@0: TransportDIB::TransportDIB() {
michael@0: }
michael@0: 
michael@0: TransportDIB::~TransportDIB() {
michael@0: }
michael@0: 
michael@0: TransportDIB::TransportDIB(HANDLE handle)
michael@0:     : shared_memory_(handle, false /* read write */) {
michael@0: }
michael@0: 
michael@0: // static
michael@0: TransportDIB* TransportDIB::Create(size_t size, uint32_t sequence_num) {
michael@0:   size_t allocation_granularity = base::SysInfo::VMAllocationGranularity();
michael@0:   size = size / allocation_granularity + 1;
michael@0:   size = size * allocation_granularity;
michael@0: 
michael@0:   TransportDIB* dib = new TransportDIB;
michael@0: 
michael@0:   if (!dib->shared_memory_.Create("", false /* read write */,
michael@0:                                   true /* open existing */, size)) {
michael@0:     delete dib;
michael@0:     return NULL;
michael@0:   }
michael@0: 
michael@0:   dib->size_ = size;
michael@0:   dib->sequence_num_ = sequence_num;
michael@0: 
michael@0:   return dib;
michael@0: }
michael@0: 
michael@0: // static
michael@0: TransportDIB* TransportDIB::Map(TransportDIB::Handle handle) {
michael@0:   TransportDIB* dib = new TransportDIB(handle);
michael@0:   if (!dib->shared_memory_.Map(0 /* map whole shared memory segment */)) {
michael@0:     CHROMIUM_LOG(ERROR) << "Failed to map transport DIB"
michael@0:                         << " handle:" << handle
michael@0:                         << " error:" << GetLastError();
michael@0:     delete dib;
michael@0:     return NULL;
michael@0:   }
michael@0: 
michael@0:   // There doesn't seem to be any way to find the size of the shared memory
michael@0:   // region! GetFileSize indicates that the handle is invalid. Thus, we
michael@0:   // conservatively set the size to the maximum and hope that the renderer
michael@0:   // isn't about to ask us to read off the end of the array.
michael@0:   dib->size_ = std::numeric_limits<size_t>::max();
michael@0: 
michael@0:   return dib;
michael@0: }
michael@0: 
michael@0: void* TransportDIB::memory() const {
michael@0:   return shared_memory_.memory();
michael@0: }
michael@0: 
michael@0: TransportDIB::Handle TransportDIB::handle() const {
michael@0:   return shared_memory_.handle();
michael@0: }
michael@0: 
michael@0: TransportDIB::Id TransportDIB::id() const {
michael@0:   return Id(shared_memory_.handle(), sequence_num_);
michael@0: }