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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "mojo/core/platform_shared_memory_mapping.h"
#include <type_traits>
#include <utility>
#include <variant>
#include "base/check.h"
#include "base/memory/read_only_shared_memory_region.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "base/memory/writable_shared_memory_region.h"
#include "base/notreached.h"
#include "build/build_config.h"
namespace mojo {
namespace core {
PlatformSharedMemoryMapping::PlatformSharedMemoryMapping(
base::subtle::PlatformSharedMemoryRegion* region,
size_t offset,
size_t length) {
switch (region->GetMode()) {
case base::subtle::PlatformSharedMemoryRegion::Mode::kReadOnly: {
auto read_only_region =
base::ReadOnlySharedMemoryRegion::Deserialize(std::move(*region));
mapping_ = read_only_region.MapAt(offset, length);
*region = base::ReadOnlySharedMemoryRegion::TakeHandleForSerialization(
std::move(read_only_region));
return;
}
case base::subtle::PlatformSharedMemoryRegion::Mode::kUnsafe: {
auto unsafe_region =
base::UnsafeSharedMemoryRegion::Deserialize(std::move(*region));
mapping_ = unsafe_region.MapAt(offset, length);
*region = base::UnsafeSharedMemoryRegion::TakeHandleForSerialization(
std::move(unsafe_region));
return;
}
case base::subtle::PlatformSharedMemoryRegion::Mode::kWritable: {
auto writable_region =
base::WritableSharedMemoryRegion::Deserialize(std::move(*region));
mapping_ = writable_region.MapAt(offset, length);
*region = base::WritableSharedMemoryRegion::TakeHandleForSerialization(
std::move(writable_region));
return;
}
}
NOTREACHED();
}
PlatformSharedMemoryMapping::~PlatformSharedMemoryMapping() = default;
bool PlatformSharedMemoryMapping::IsValid() const {
return std::visit(
[](const auto& member) {
using T = std::decay_t<decltype(member)>;
if constexpr (std::is_same_v<T, std::monostate>) {
return false;
} else {
return member.IsValid();
}
},
mapping_);
}
void* PlatformSharedMemoryMapping::GetBase() const {
return std::visit(
[](const auto& member) -> void* {
using T = std::decay_t<decltype(member)>;
if constexpr (std::is_same_v<T, std::monostate>) {
return nullptr;
} else {
return const_cast<void*>(member.memory());
}
},
mapping_);
}
size_t PlatformSharedMemoryMapping::GetLength() const {
return std::visit(
[](const auto& member) -> size_t {
using T = std::decay_t<decltype(member)>;
if constexpr (std::is_same_v<T, std::monostate>) {
return 0;
} else {
return member.size();
}
},
mapping_);
}
} // namespace core
} // namespace mojo
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