зеркало из https://github.com/mozilla/gecko-dev.git
140 строки
4.4 KiB
C++
140 строки
4.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef mozilla_ipc_FileDescriptor_h
|
|
#define mozilla_ipc_FileDescriptor_h
|
|
|
|
#include "base/basictypes.h"
|
|
#include "base/process.h"
|
|
#include "mozilla/UniquePtr.h"
|
|
#include "ipc/IPCMessageUtils.h"
|
|
#include "mozilla/ipc/IPDLParamTraits.h"
|
|
|
|
#ifdef XP_WIN
|
|
// Need the HANDLE typedef.
|
|
# include <winnt.h>
|
|
# include <cstdint>
|
|
#else
|
|
# include "base/file_descriptor_posix.h"
|
|
#endif
|
|
|
|
namespace mozilla {
|
|
namespace ipc {
|
|
|
|
// This class is used by IPDL to share file descriptors across processes. When
|
|
// sending a FileDescriptor IPDL will first duplicate a platform-specific file
|
|
// handle type ('PlatformHandleType') into a handle that is valid in the other
|
|
// process. Then IPDL will convert the duplicated handle into a type suitable
|
|
// for pickling ('PickleType') and then send that through the IPC pipe. In the
|
|
// receiving process the pickled data is converted into a platform-specific file
|
|
// handle and then returned to the receiver.
|
|
//
|
|
// To use this class add 'FileDescriptor' as an argument in the IPDL protocol
|
|
// and then pass a file descriptor from C++ to the Call/Send method. The
|
|
// Answer/Recv method will receive a FileDescriptor& on which PlatformHandle()
|
|
// can be called to return the platform file handle.
|
|
class FileDescriptor {
|
|
public:
|
|
typedef base::ProcessId ProcessId;
|
|
|
|
#ifdef XP_WIN
|
|
typedef HANDLE PlatformHandleType;
|
|
typedef HANDLE PickleType;
|
|
#else
|
|
typedef int PlatformHandleType;
|
|
typedef base::FileDescriptor PickleType;
|
|
#endif
|
|
|
|
struct PlatformHandleHelper {
|
|
MOZ_IMPLICIT PlatformHandleHelper(PlatformHandleType aHandle);
|
|
MOZ_IMPLICIT PlatformHandleHelper(std::nullptr_t);
|
|
bool operator!=(std::nullptr_t) const;
|
|
operator PlatformHandleType() const;
|
|
#ifdef XP_WIN
|
|
operator std::intptr_t() const;
|
|
#endif
|
|
private:
|
|
PlatformHandleType mHandle;
|
|
};
|
|
struct PlatformHandleDeleter {
|
|
typedef PlatformHandleHelper pointer;
|
|
void operator()(PlatformHandleHelper aHelper);
|
|
};
|
|
typedef UniquePtr<PlatformHandleType, PlatformHandleDeleter>
|
|
UniquePlatformHandle;
|
|
|
|
// This should only ever be created by IPDL.
|
|
struct IPDLPrivate {};
|
|
|
|
// Represents an invalid handle.
|
|
FileDescriptor();
|
|
|
|
// Copy constructor will duplicate a new handle.
|
|
FileDescriptor(const FileDescriptor& aOther);
|
|
|
|
FileDescriptor(FileDescriptor&& aOther);
|
|
|
|
// This constructor will duplicate a new handle.
|
|
// The caller still have to close aHandle.
|
|
explicit FileDescriptor(PlatformHandleType aHandle);
|
|
|
|
// This constructor WILL NOT duplicate the handle.
|
|
// FileDescriptor takes the ownership from IPC message.
|
|
FileDescriptor(const IPDLPrivate&, const PickleType& aPickle);
|
|
|
|
~FileDescriptor();
|
|
|
|
FileDescriptor& operator=(const FileDescriptor& aOther);
|
|
|
|
FileDescriptor& operator=(FileDescriptor&& aOther);
|
|
|
|
// Performs platform-specific actions to duplicate mHandle in the other
|
|
// process (e.g. dup() on POSIX, DuplicateHandle() on Windows). Returns a
|
|
// pickled value that can be passed to the other process via IPC.
|
|
PickleType ShareTo(const IPDLPrivate&, ProcessId aTargetPid) const;
|
|
|
|
// Tests mHandle against a well-known invalid platform-specific file handle
|
|
// (e.g. -1 on POSIX, INVALID_HANDLE_VALUE on Windows).
|
|
bool IsValid() const;
|
|
|
|
// Returns a duplicated handle, it is caller's responsibility to close the
|
|
// handle.
|
|
UniquePlatformHandle ClonePlatformHandle() const;
|
|
|
|
// Only used in nsTArray.
|
|
bool operator==(const FileDescriptor& aOther) const;
|
|
|
|
private:
|
|
friend struct PlatformHandleTrait;
|
|
|
|
void Assign(const FileDescriptor& aOther);
|
|
|
|
void Close();
|
|
|
|
static bool IsValid(PlatformHandleType aHandle);
|
|
|
|
static PlatformHandleType Clone(PlatformHandleType aHandle);
|
|
|
|
static void Close(PlatformHandleType aHandle);
|
|
|
|
PlatformHandleType mHandle;
|
|
};
|
|
|
|
template <>
|
|
struct IPDLParamTraits<FileDescriptor> {
|
|
typedef FileDescriptor paramType;
|
|
|
|
static void Write(IPC::Message* aMsg, IProtocol* aActor,
|
|
const paramType& aParam);
|
|
static bool Read(const IPC::Message* aMsg, PickleIterator* aIter,
|
|
IProtocol* aActor, paramType* aResult);
|
|
};
|
|
|
|
} // namespace ipc
|
|
} // namespace mozilla
|
|
|
|
#endif // mozilla_ipc_FileDescriptor_h
|