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// Copyright 2014 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 "mojo/embedder/simple_platform_shared_buffer.h"
#include <windows.h>
#include <limits>
#include "base/logging.h"
#include "base/sys_info.h"
#include "mojo/embedder/platform_handle.h"
#include "mojo/embedder/scoped_platform_handle.h"
namespace mojo {
namespace embedder {
// SimplePlatformSharedBuffer --------------------------------------------------
bool SimplePlatformSharedBuffer::Init() {
DCHECK(!handle_.is_valid());
// TODO(vtl): Currently, we only support mapping up to 2^32-1 bytes.
if (static_cast<uint64_t>(num_bytes_) >
static_cast<uint64_t>(std::numeric_limits<DWORD>::max())) {
return false;
}
// IMPORTANT NOTE: Unnamed objects are NOT SECURABLE. Thus if we ever want to
// share read-only to other processes, we'll have to name our file mapping
// object.
// TODO(vtl): Unlike |base::SharedMemory|, we don't round up the size (to a
// multiple of 64 KB). This may cause problems with NaCl. Cross this bridge
// when we get there. crbug.com/210609
handle_.reset(PlatformHandle(CreateFileMapping(INVALID_HANDLE_VALUE,
nullptr,
PAGE_READWRITE,
0,
static_cast<DWORD>(num_bytes_),
nullptr)));
if (!handle_.is_valid()) {
PLOG(ERROR) << "CreateFileMapping";
return false;
}
return true;
}
bool SimplePlatformSharedBuffer::InitFromPlatformHandle(
ScopedPlatformHandle platform_handle) {
DCHECK(!handle_.is_valid());
// TODO(vtl): Implement.
NOTIMPLEMENTED();
return false;
}
scoped_ptr<PlatformSharedBufferMapping> SimplePlatformSharedBuffer::MapImpl(
size_t offset,
size_t length) {
size_t offset_rounding = offset % base::SysInfo::VMAllocationGranularity();
size_t real_offset = offset - offset_rounding;
size_t real_length = length + offset_rounding;
// This should hold (since we checked |num_bytes| versus the maximum value of
// |off_t| on creation, but it never hurts to be paranoid.
DCHECK_LE(static_cast<uint64_t>(real_offset),
static_cast<uint64_t>(std::numeric_limits<DWORD>::max()));
void* real_base = MapViewOfFile(handle_.get().handle,
FILE_MAP_READ | FILE_MAP_WRITE,
0,
static_cast<DWORD>(real_offset),
real_length);
if (!real_base) {
PLOG(ERROR) << "MapViewOfFile";
return nullptr;
}
void* base = static_cast<char*>(real_base) + offset_rounding;
return make_scoped_ptr(new SimplePlatformSharedBufferMapping(
base, length, real_base, real_length));
}
// SimplePlatformSharedBufferMapping -------------------------------------------
void SimplePlatformSharedBufferMapping::Unmap() {
BOOL result = UnmapViewOfFile(real_base_);
PLOG_IF(ERROR, !result) << "UnmapViewOfFile";
}
} // namespace embedder
} // namespace mojo
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