Introduce base::ScopedPlatformHandle

base/files/scoped_platform_handle.cc

Index: base/files/scoped_platform_handle.cc
diff --git a/base/files/scoped_platform_handle.cc b/base/files/scoped_platform_handle.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a6528732ba7b9040f3a397fd2eb1b78b7bc31407
--- /dev/null
+++ b/base/files/scoped_platform_handle.cc
@@ -0,0 +1,241 @@
+// Copyright 2017 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 "base/files/scoped_platform_handle.h"
+
+#include "base/logging.h"
+
+namespace base {
+
+ScopedPlatformHandle::ScopedPlatformHandle() : ScopedPlatformHandle(nullptr) {}
+
+ScopedPlatformHandle::ScopedPlatformHandle(std::nullptr_t)
+    : type_(Type::INVALID) {}
+
+ScopedPlatformHandle::ScopedPlatformHandle(ScopedPlatformHandle&& other) {
+  *this = std::move(other);
+}
+
+#if defined(OS_WIN)
+ScopedPlatformHandle::ScopedPlatformHandle(HANDLE handle)
+    : type_(Type::WINDOWS_HANDLE), windows_handle_(handle) {}
+
+ScopedPlatformHandle::ScopedPlatformHandle(win::ScopedHandle handle)
+    : type_(Type::WINDOWS_HANDLE), windows_handle_(std::move(handle)) {}
+
+#elif defined(OS_POSIX)
+
+ScopedPlatformHandle::ScopedPlatformHandle(int fd)
+    : type_(Type::FILE_DESCRIPTOR), file_descriptor_(fd) {}
+
+ScopedPlatformHandle::ScopedPlatformHandle(ScopedFD fd)
+    : type_(Type::FILE_DESCRIPTOR), file_descriptor_(std::move(fd)) {}
+
+#endif  // defined(OS_WIN)
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+
+ScopedPlatformHandle::ScopedPlatformHandle(mach_port_t port)
+    : type_(Type::MACH_PORT_SEND), mach_port_send_(port) {}
+
+ScopedPlatformHandle::ScopedPlatformHandle(mac::ScopedMachSendRight port)
+    : type_(Type::MACH_PORT_SEND), mach_port_send_(std::move(port)) {}
+
+ScopedPlatformHandle::ScopedPlatformHandle(mac::ScopedMachReceiveRight port)
+    : type_(Type::MACH_PORT_RECEIVE), mach_port_receive_(std::move(port)) {}
+
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
+
+ScopedPlatformHandle::~ScopedPlatformHandle() {
+  reset();
+}
+
+ScopedPlatformHandle& ScopedPlatformHandle::operator=(
+    ScopedPlatformHandle&& other) {
+  // NOTE: It's important that we invoke the appropriate destructor here if
+  // necessary, since we may be transitioning from one handle type to another.
+  reset();
+
+  std::swap(type_, other.type_);
+
+  switch (type_) {
+    case Type::INVALID:
+      break;
+#if defined(OS_WIN)
+    case Type::WINDOWS_HANDLE:
+      new (&windows_handle_)
+          win::ScopedHandle(std::move(other.windows_handle_));
+      break;
+#elif defined(OS_POSIX)
+    case Type::FILE_DESCRIPTOR:
+      new (&file_descriptor_) ScopedFD(std::move(other.file_descriptor_));
+      break;
+#endif
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+    case Type::MACH_PORT_SEND:
+      new (&mach_port_send_)
+          mac::ScopedMachSendRight(std::move(mach_port_send_));
+      break;
+    case Type::MACH_PORT_RECEIVE:
+      new (&mach_port_receive_)
+          mac::ScopedMachReceiveRight(std::move(mach_port_receive_));
+      break;
+#endif
+  }
+
+  return *this;
+}
+
+bool ScopedPlatformHandle::is_valid() const {
+  switch (type_) {
+    case Type::INVALID:
+      return false;
+
+#if defined(OS_WIN)
+    case Type::WINDOWS_HANDLE:
+      return windows_handle_.IsValid();
+#elif defined(OS_POSIX)
+    case Type::FILE_DESCRIPTOR:
+      return file_descriptor_.is_valid();
+#endif
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+    case Type::MACH_PORT_SEND:
+      return mach_port_send_.is_valid();
+    case Type::MACH_PORT_RECEIVE:
+      return mach_port_receive_.is_valid();
+#endif
+  }
+
+  NOTREACHED();
+  return false;
+}
+
+void ScopedPlatformHandle::reset() {
+  switch (type_) {
+    case Type::INVALID:
+      break;
+#if defined(OS_WIN)
+    case Type::WINDOWS_HANDLE:
+      windows_handle_.~GenericScopedHandle();
+      break;
+#elif defined(OS_POSIX)
+    case Type::FILE_DESCRIPTOR:
+      file_descriptor_.~ScopedGeneric();
+      break;
+#endif
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+    case Type::MACH_PORT_SEND:
+      mach_port_send_.~ScopedGeneric();
+      break;
+    case Type::MACH_PORT_RECEIVE:
+      mach_port_receive_.~ScopedGeneric();
+      break;
+#endif
+  }
+
+  type_ = Type::INVALID;
+}
+
+#if defined(OS_WIN)
+
+bool ScopedPlatformHandle::GetAsWindowsHandle(HANDLE* handle) const {
+  if (type_ != Type::WINDOWS_HANDLE)
+    return false;
+  *handle = windows_handle_.Get();
+  return true;
+}
+
+bool ScopedPlatformHandle::TakeWindowsHandle(win::ScopedHandle* handle) {
+  if (type_ != Type::WINDOWS_HANDLE)
+    return false;
+  *handle = std::move(windows_handle_);
+  type_ = Type::INVALID;
+  return true;
+}
+
+bool ScopedPlatformHandle::ReleaseAsWindowsHandle(HANDLE* handle) {
+  if (type_ != Type::WINDOWS_HANDLE)
+    return false;
+  *handle = windows_handle_.Take();
+  type_ = Type::INVALID;
+  return true;
+}
+
+#elif defined(OS_POSIX)
+
+bool ScopedPlatformHandle::GetAsFileDescriptor(int* fd) const {
+  if (type_ != Type::FILE_DESCRIPTOR)
+    return false;
+  *fd = file_descriptor_.get();
+  return true;
+}
+
+bool ScopedPlatformHandle::TakeFileDescriptor(ScopedFD* fd) {
+  if (type_ != Type::FILE_DESCRIPTOR)
+    return false;
+  *fd = std::move(file_descriptor_);
+  type_ = Type::INVALID;
+  return true;
+}
+
+bool ScopedPlatformHandle::ReleaseAsFileDescriptor(int* fd) {
+  if (type_ != Type::FILE_DESCRIPTOR)
+    return false;
+  *fd = file_descriptor_.release();
+  type_ = Type::INVALID;
+  return true;
+}
+
+#endif  // defined(OS_WIN)
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+
+bool ScopedPlatformHandle::GetAsMachPort(mach_port_t* port) const {
+  if (type_ == Type::MACH_PORT_SEND) {
+    *port = mach_port_send_.get();
+    return true;
+  } else if (type_ == Type::MACH_PORT_RECEIVE) {
+    *port = mach_port_receive_.get();
+    return true;
+  }
+  return false;
+}
+
+bool ScopedPlatformHandle::TakeMachPortSendRight(
+    mac::ScopedMachSendRight* port) {
+  if (type_ != Type::MACH_PORT_SEND)
+    return false;
+  *port = std::move(mach_port_send_);
+  type_ = Type::INVALID;
+  return true;
+}
+
+bool ScopedPlatformHandle::TakeMachPortReceiveRight(
+    mac::ScopedMachReceiveRight* port) {
+  if (type_ != Type::MACH_PORT_RECEIVE)
+    return false;
+  *port = std::move(mach_port_receive_);
+  type_ = Type::INVALID;
+  return true;
+}
+
+bool ScopedPlatformHandle::ReleaseAsMachPort(mach_port_t* port) {
+  if (type_ == Type::MACH_PORT_SEND) {
+    *port = mach_port_send_.release();
+    type_ = Type::INVALID;
+    return true;
+  } else if (type_ == Type::MACH_PORT_RECEIVE) {
+    *port = mach_port_receive_.release();
+    type_ = Type::INVALID;
+    return true;
+  }
+  return false;
+}
+
+#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
+
+}  // namespace base