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ed88dc4370
This makes passing around the type more consistent, and hopefully will make changes to IPC::Message easier to work with in the future. In addition, this should save us a few copies as we move the message type into and out of UniquePtr, however I expect this won't make much of a difference. Differential Revision: https://phabricator.services.mozilla.com/D145885
119 lines
3.6 KiB
C++
119 lines
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* vim: set ts=8 sts=4 et sw=4 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef __MINITRANSCEIVER_H_
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#define __MINITRANSCEIVER_H_
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#include "chrome/common/ipc_message.h"
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#include "mozilla/Assertions.h"
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struct msghdr;
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namespace mozilla {
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namespace ipc {
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enum class DataBufferClear { None, AfterReceiving };
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/**
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* This simple implementation handles the transmissions of IPC
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* messages.
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*
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* It works according to a strict request-response paradigm, no
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* concurrent messaging is allowed. Sending a message from A to B must
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* be followed by another one from B to A. Because of this we don't
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* need to handle data crossing the boundaries of a
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* message. Transmission is done via blocking I/O to avoid the
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* complexity of asynchronous I/O.
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*/
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class MiniTransceiver {
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public:
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/**
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* \param aFd should be a blocking, no O_NONBLOCK, fd.
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* \param aClearDataBuf is true to clear data buffers after
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* receiving a message.
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*/
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explicit MiniTransceiver(
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int aFd, DataBufferClear aDataBufClear = DataBufferClear::None);
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bool Send(IPC::Message& aMsg);
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inline bool SendInfallible(IPC::Message& aMsg, const char* aCrashMessage) {
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bool Ok = Send(aMsg);
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if (!Ok) {
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MOZ_CRASH_UNSAFE(aCrashMessage);
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}
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return Ok;
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}
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/**
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* \param aMsg will hold the content of the received message.
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* \return false if the fd is closed or with an error.
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*/
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bool Recv(UniquePtr<IPC::Message>& aMsg);
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inline bool RecvInfallible(UniquePtr<IPC::Message>& aMsg,
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const char* aCrashMessage) {
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bool Ok = Recv(aMsg);
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if (!Ok) {
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MOZ_CRASH_UNSAFE(aCrashMessage);
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}
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return Ok;
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}
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int GetFD() { return mFd; }
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private:
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/**
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* Set control buffer to make file descriptors ready to be sent
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* through a socket.
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*/
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void PrepareFDs(msghdr* aHdr, IPC::Message& aMsg);
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/**
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* Collect buffers of the message and make them ready to be sent.
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*
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* \param aHdr is the structure going to be passed to sendmsg().
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* \param aMsg is the Message to send.
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*/
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size_t PrepareBuffers(msghdr* aHdr, IPC::Message& aMsg);
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/**
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* Collect file descriptors received.
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*
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* \param aAllFds is where to store file descriptors.
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* \param aMaxFds is how many file descriptors can be stored in aAllFds.
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* \return the number of received file descriptors.
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*/
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unsigned RecvFDs(msghdr* aHdr, int* aAllFds, unsigned aMaxFds);
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/**
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* Received data from the socket.
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*
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* \param aDataBuf is where to store the data from the socket.
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* \param aBufSize is the size of the buffer.
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* \param aMsgSize returns how many bytes were readed from the socket.
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* \param aFdsBuf is the buffer to return file desriptors received.
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* \param aMaxFds is the number of file descriptors that can be held.
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* \param aNumFds returns the number of file descriptors received.
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* \return true if sucess, or false for error.
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*/
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bool RecvData(char* aDataBuf, size_t aBufSize, uint32_t* aMsgSize,
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int* aFdsBuf, unsigned aMaxFds, unsigned* aNumFds);
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int mFd; // The file descriptor of the socket for IPC.
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#ifdef DEBUG
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enum State {
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STATE_NONE,
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STATE_SENDING,
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STATE_RECEIVING,
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};
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State mState;
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#endif
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// Clear all received data in temp buffers to avoid data leaking.
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DataBufferClear mDataBufClear;
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};
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} // namespace ipc
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} // namespace mozilla
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#endif // __MINITRANSCEIVER_H_
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