gecko-dev/mozglue/build/Nuwa.h

172 строки
5.2 KiB
C

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=2 autoindent cindent expandtab: */
/* 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 __NUWA_H_
#define __NUWA_H_
#include <setjmp.h>
#include <unistd.h>
#include "mozilla/Types.h"
/**
* Nuwa is a goddess who created mankind according to her figure in the
* ancient Chinese mythology.
*/
// Max number of top level protocol that can be handled by Nuwa process.
#ifndef NUWA_TOPLEVEL_MAX
#define NUWA_TOPLEVEL_MAX 8
#endif
struct NuwaProtoFdInfo {
int protoId;
int originFd;
int newFds[2];
};
#define NUWA_NEWFD_PARENT 0
#define NUWA_NEWFD_CHILD 1
extern "C" {
/**
* The following 3 methods are used to synchronously spawn the Nuwa process.
* The typical usage is:
*
* The IPC thread The main thread
* 1. Receives the request.
* 2. NuwaSpawnPrepare().
* 3. Request main thread to
* spawn. --------------------------------------+
* 4. NuwaSpawnWait(). V
* 5. NuwaSpawn() to clone all
* the threads in the Nuwa
* process (including main
* & IPC threads).
* 6. NuwaSpawn() finishes and
* +-------------------------------------- signals NuwaSpawnWait().
* V
* 7. NuwaSpawnWait() returns.
*/
/**
* Prepare for spawning a new process. The calling thread (typically the IPC
* thread) will block further requests to spawn a new process.
*/
MFBT_API void NuwaSpawnPrepare();
/**
* Called on the thread that receives the request. Used to wait until
* NuwaSpawn() finishes and maintain the stack of the calling thread.
*/
MFBT_API void NuwaSpawnWait();
/**
* Spawn a new content process, called in the Nuwa process. This has to run on
* the main thread.
*
* @return The process ID of the new process.
*/
MFBT_API pid_t NuwaSpawn();
/**
* The following methods are for marking threads created in the Nuwa process so
* they can be frozen and then recreated in the spawned process. All threads
* except the main thread must be marked by one of the following 4 methods;
* otherwise, we have a thread that is created but unknown to us. The Nuwa
* process will never become ready and this needs to be fixed.
*/
/**
* Mark the current thread as supporting Nuwa. The thread will implicitly freeze
* by calling a blocking method such as pthread_mutex_lock() or epoll_wait().
*
* @param recreate The custom function that will be called in the spawned
* process, after the thread is recreated. Can be nullptr if no
* custom function to be called after the thread is recreated.
* @param arg The argument passed to the custom function. Can be nullptr.
*/
MFBT_API void NuwaMarkCurrentThread(void (*recreate)(void *), void *arg);
/**
* Mark the current thread as not supporting Nuwa. The calling thread will not
* be automatically cloned from the Nuwa process to spawned process. If this
* thread needs to be created in the spawned process, use NuwaAddConstructor()
* or NuwaAddFinalConstructor() to do it.
*/
MFBT_API void NuwaSkipCurrentThread();
/**
* Force the current thread to freeze explicitly at the current point.
*/
MFBT_API void NuwaFreezeCurrentThread();
/**
* Helper functions for the NuwaCheckpointCurrentThread() macro.
*/
MFBT_API jmp_buf* NuwaCheckpointCurrentThread1();
MFBT_API bool NuwaCheckpointCurrentThread2(int setjmpCond);
/**
* Set the point to recover after thread recreation. The calling thread is not
* blocked. This is used for the thread that cannot freeze (i.e. the IPC
* thread).
*/
#define NuwaCheckpointCurrentThread() \
NuwaCheckpointCurrentThread2(setjmp(*NuwaCheckpointCurrentThread1()))
/**
* The following methods are called in the initialization stage of the Nuwa
* process.
*/
/**
* Prepare for making the Nuwa process.
*/
MFBT_API void PrepareNuwaProcess();
/**
* Make the current process a Nuwa process. Start to freeze the threads.
*/
MFBT_API void MakeNuwaProcess();
/**
* Register a method to be invoked after a new process is spawned. The method
* will be invoked on the main thread.
*
* @param construct The method to be invoked.
* @param arg The argument passed to the method.
*/
MFBT_API void NuwaAddConstructor(void (*construct)(void *), void *arg);
/**
* Register a method to be invoked after a new process is spawned and threads
* are recreated. The method will be invoked on the main thread.
*
* @param construct The method to be invoked.
* @param arg The argument passed to the method.
*/
MFBT_API void NuwaAddFinalConstructor(void (*construct)(void *), void *arg);
/**
* The methods to query the Nuwa-related states.
*/
/**
* @return If the current process is the Nuwa process.
*/
MFBT_API bool IsNuwaProcess();
/**
* @return If the Nuwa process is ready for spawning new processes.
*/
MFBT_API bool IsNuwaReady();
};
#endif /* __NUWA_H_ */