co_routine.cpp

/*
* Tencent is pleased to support the open source community by making Libco available.

* Copyright (C) 2014 THL A29 Limited, a Tencent company. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); 
* you may not use this file except in compliance with the License. 
* You may obtain a copy of the License at
*
*	http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, 
* software distributed under the License is distributed on an "AS IS" BASIS, 
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
* See the License for the specific language governing permissions and 
* limitations under the License.
*/

#include "co_routine.h"
#include "co_routine_inner.h"
#include "co_epoll.h"

#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <string>
#include <map>

#include <poll.h>
#include <sys/time.h>
#include <errno.h>

#include <assert.h>

#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <limits.h>

extern "C"
{
	extern void coctx_swap( coctx_t *,coctx_t* ) asm("coctx_swap");
};
using namespace std;
stCoRoutine_t *GetCurrCo( stCoRoutineEnv_t *env );
struct stCoEpoll_t;

struct stCoRoutineEnv_t
{
	/*pCallStack是用来保留程序运行过程中局部变量以及函数调用关系的
	每当启动（resume）一个协程时，就将它的协程控制块 stCoRoutine_t 结构指针保存在 pCallStack 的“栈顶”，
	然后“栈指针”iCallStackSize 加 1，最后切换 context 到待启动协程运行。当协程要让出（yield）CPU 时，
	就将它的 stCoRoutine_t 从 pCallStack 弹出，“栈指针”iCallStackSize 减 1，
	然后切换 context 到当前栈顶的协程（原来被挂起的调用者）恢复执行。
	*/
	stCoRoutine_t *pCallStack[ 128 ];
	int iCallStackSize;
	stCoEpoll_t *pEpoll;

	//for copy stack log lastco and nextco
	stCoRoutine_t* pending_co;
	stCoRoutine_t* occupy_co;
};
//int socket(int domain, int type, int protocol);
void co_log_err( const char *fmt,... )
{
}


#if defined( __LIBCO_RDTSCP__) 
static unsigned long long counter(void)
{
	register uint32_t lo, hi;
	register unsigned long long o;
	__asm__ __volatile__ (
			"rdtscp" : "=a"(lo), "=d"(hi)::"%rcx"
			);
	o = hi;
	o <<= 32;
	return (o | lo);

}
static unsigned long long getCpuKhz()
{
	FILE *fp = fopen("/proc/cpuinfo","r");
	if(!fp) return 1;
	char buf[4096] = {0};
	fread(buf,1,sizeof(buf),fp);
	fclose(fp);

	char *lp = strstr(buf,"cpu MHz");
	if(!lp) return 1;
	lp += strlen("cpu MHz");
	while(*lp == ' ' || *lp == '\t' || *lp == ':')
	{
		++lp;
	}

	double mhz = atof(lp);
	unsigned long long u = (unsigned long long)(mhz * 1000);
	return u;
}
#endif

static unsigned long long GetTickMS()
{
#if defined( __LIBCO_RDTSCP__) 
	static uint32_t khz = getCpuKhz();
	return counter() / khz;
#else
	struct timeval now = { 0 };
	gettimeofday( &now,NULL );
	unsigned long long u = now.tv_sec;
	u *= 1000;
	u += now.tv_usec / 1000;
	return u;
#endif
}

static pid_t GetPid()
{
    static __thread pid_t pid = 0;
    static __thread pid_t tid = 0;
    if( !pid || !tid || pid != getpid() )
    {
        pid = getpid();
#if defined( __APPLE__ )
		tid = syscall( SYS_gettid );
		if( -1 == (long)tid )
		{
			tid = pid;
		}
#elif defined( __FreeBSD__ )
		syscall(SYS_thr_self, &tid);
		if( tid < 0 )
		{
			tid = pid;
		}
#else 
        tid = syscall( __NR_gettid );
#endif

    }
    return tid;

}
/*
static pid_t GetPid()
{
	char **p = (char**)pthread_self();
	return p ? *(pid_t*)(p + 18) : getpid();
}
*/
template <class T,class TLink>
void RemoveFromLink(T *ap)
{
	TLink *lst = ap->pLink;
	if(!lst) return ;
	assert( lst->head && lst->tail );

	if( ap == lst->head )
	{
		lst->head = ap->pNext;
		if(lst->head)
		{
			lst->head->pPrev = NULL;
		}
	}
	else
	{
		if(ap->pPrev)
		{
			ap->pPrev->pNext = ap->pNext;
		}
	}

	if( ap == lst->tail )
	{
		lst->tail = ap->pPrev;
		if(lst->tail)
		{
			lst->tail->pNext = NULL;
		}
	}
	else
	{
		ap->pNext->pPrev = ap->pPrev;
	}

	ap->pPrev = ap->pNext = NULL;
	ap->pLink = NULL;
}

template <class TNode,class TLink>
void inline AddTail(TLink*apLink,TNode *ap)
{
	if( ap->pLink )
	{
		return ;
	}
	if(apLink->tail)
	{
		apLink->tail->pNext = (TNode*)ap;
		ap->pNext = NULL;
		ap->pPrev = apLink->tail;
		apLink->tail = ap;
	}
	else
	{
		apLink->head = apLink->tail = ap;
		ap->pNext = ap->pPrev = NULL;
	}
	ap->pLink = apLink;
}
template <class TNode,class TLink>
void inline PopHead( TLink*apLink )
{
	if( !apLink->head ) 
	{
		return ;
	}
	TNode *lp = apLink->head;
	if( apLink->head == apLink->tail )
	{
		apLink->head = apLink->tail = NULL;
	}
	else
	{
		apLink->head = apLink->head->pNext;
	}

	lp->pPrev = lp->pNext = NULL;
	lp->pLink = NULL;

	if( apLink->head )
	{
		apLink->head->pPrev = NULL;
	}
}

template <class TNode,class TLink>
void inline Join( TLink*apLink,TLink *apOther )
{
	//printf("apOther %p\n",apOther);
	if( !apOther->head )
	{
		return ;
	}
	TNode *lp = apOther->head;
	while( lp )
	{
		lp->pLink = apLink;
		lp = lp->pNext;
	}
	lp = apOther->head;
	if(apLink->tail)
	{
		apLink->tail->pNext = (TNode*)lp;
		lp->pPrev = apLink->tail;
		apLink->tail = apOther->tail;
	}
	else
	{
		apLink->head = apOther->head;
		apLink->tail = apOther->tail;
	}

	apOther->head = apOther->tail = NULL;
}

/////////////////for copy stack //////////////////////////
stStackMem_t* co_alloc_stackmem(unsigned int stack_size)
{
	stStackMem_t* stack_mem = (stStackMem_t*)malloc(sizeof(stStackMem_t));
	stack_mem->occupy_co= NULL;
	stack_mem->stack_size = stack_size;
	stack_mem->stack_buffer = (char*)malloc(stack_size);
	stack_mem->stack_bp = stack_mem->stack_buffer + stack_size;
	return stack_mem;
}

stShareStack_t* co_alloc_sharestack(int count, int stack_size)
{
	stShareStack_t* share_stack = (stShareStack_t*)malloc(sizeof(stShareStack_t));
	share_stack->alloc_idx = 0;
	share_stack->stack_size = stack_size;

	//alloc stack array
	share_stack->count = count;
	stStackMem_t** stack_array = (stStackMem_t**)calloc(count, sizeof(stStackMem_t*));
	for (int i = 0; i < count; i++)
	{
		stack_array[i] = co_alloc_stackmem(stack_size);
	}
	share_stack->stack_array = stack_array;
	return share_stack;
}

static stStackMem_t* co_get_stackmem(stShareStack_t* share_stack)
{
	if (!share_stack)
	{
		return NULL;
	}
	int idx = share_stack->alloc_idx % share_stack->count;
	share_stack->alloc_idx++;

	return share_stack->stack_array[idx];
}


// ----------------------------------------------------------------------------
struct stTimeoutItemLink_t;
struct stTimeoutItem_t;
struct stCoEpoll_t//该结构体重维护了事件循环需要的数据
{
	int iEpollFd;//epoll或者kqueue的fd
	static const int _EPOLL_SIZE = 1024 * 10;//作为 epoll_wait() 系统调用的第三个参数，即⼀次 epoll_wait 最多返回的就绪事件个数。

	struct stTimeout_t *pTimeout;//类型为 stTimeout_t 的结构体指针。该结构实际上是⼀个时间轮（Timingwheel）定时器,记录了所有的定时事件

	struct stTimeoutItemLink_t *pstTimeoutList;//指向 stTimeoutItemLink_t 类型的结构体指针。该指针实际上是⼀个链表头。链表用于临时存放超时事件的 item。本轮超时的事件

	struct stTimeoutItemLink_t *pstActiveList;//指向 stTimeoutItemLink_t 类型的结构体指针。也是指向⼀个链表。该链表用于存放 epoll_wait 得到的就绪事件和定时器超时事件。本轮触发的事件

	co_epoll_res *result; //对 epoll_wait()第⼆个参数的封装，即⼀次 epoll_wait 得到的结果集

};
typedef void (*OnPreparePfn_t)( stTimeoutItem_t *,struct epoll_event &ev, stTimeoutItemLink_t *active );
typedef void (*OnProcessPfn_t)( stTimeoutItem_t *);
struct stTimeoutItem_t
{

	enum
	{
		eMaxTimeout = 40 * 1000 //40s
	};
	stTimeoutItem_t *pPrev;
	stTimeoutItem_t *pNext;
	stTimeoutItemLink_t *pLink;

	unsigned long long ullExpireTime;

	OnPreparePfn_t pfnPrepare;
	OnProcessPfn_t pfnProcess;

	void *pArg; // routine 
	bool bTimeout;
};
struct stTimeoutItemLink_t
{
	stTimeoutItem_t *head;
	stTimeoutItem_t *tail;

};
struct stTimeout_t
{
	stTimeoutItemLink_t *pItems;
	int iItemSize;

	unsigned long long ullStart;
	long long llStartIdx;
};
stTimeout_t *AllocTimeout( int iSize )
{
	stTimeout_t *lp = (stTimeout_t*)calloc( 1,sizeof(stTimeout_t) );	

	lp->iItemSize = iSize;
	lp->pItems = (stTimeoutItemLink_t*)calloc( 1,sizeof(stTimeoutItemLink_t) * lp->iItemSize );

	lp->ullStart = GetTickMS();
	lp->llStartIdx = 0;

	return lp;
}
void FreeTimeout( stTimeout_t *apTimeout )
{
	free( apTimeout->pItems );
	free ( apTimeout );
}
int AddTimeout( stTimeout_t *apTimeout,stTimeoutItem_t *apItem ,unsigned long long allNow )
{
	if( apTimeout->ullStart == 0 )
	{
		apTimeout->ullStart = allNow;
		apTimeout->llStartIdx = 0;
	}
	if( allNow < apTimeout->ullStart )
	{
		co_log_err("CO_ERR: AddTimeout line %d allNow %llu apTimeout->ullStart %llu",
					__LINE__,allNow,apTimeout->ullStart);

		return __LINE__;
	}
	if( apItem->ullExpireTime < allNow )
	{
		co_log_err("CO_ERR: AddTimeout line %d apItem->ullExpireTime %llu allNow %llu apTimeout->ullStart %llu",
					__LINE__,apItem->ullExpireTime,allNow,apTimeout->ullStart);

		return __LINE__;
	}
	unsigned long long diff = apItem->ullExpireTime - apTimeout->ullStart;

	if( diff >= (unsigned long long)apTimeout->iItemSize )
	{
		diff = apTimeout->iItemSize - 1;
		co_log_err("CO_ERR: AddTimeout line %d diff %d",
					__LINE__,diff);

		//return __LINE__;
	}
	AddTail( apTimeout->pItems + ( apTimeout->llStartIdx + diff ) % apTimeout->iItemSize , apItem );

	return 0;
}
inline void TakeAllTimeout( stTimeout_t *apTimeout,unsigned long long allNow,stTimeoutItemLink_t *apResult )
{
	if( apTimeout->ullStart == 0 )
	{
		apTimeout->ullStart = allNow;
		apTimeout->llStartIdx = 0;
	}

	if( allNow < apTimeout->ullStart )
	{
		return ;
	}
	int cnt = allNow - apTimeout->ullStart + 1;
	if( cnt > apTimeout->iItemSize )
	{
		cnt = apTimeout->iItemSize;
	}
	if( cnt < 0 )
	{
		return;
	}
	for( int i = 0;i<cnt;i++)
	{
		int idx = ( apTimeout->llStartIdx + i) % apTimeout->iItemSize;
		Join<stTimeoutItem_t,stTimeoutItemLink_t>( apResult,apTimeout->pItems + idx  );
	}
	apTimeout->ullStart = allNow;
	apTimeout->llStartIdx += cnt - 1;


}
static int CoRoutineFunc( stCoRoutine_t *co,void * )
{
	if( co->pfn )
	{
		co->pfn( co->arg );
	}
	co->cEnd = 1;

	stCoRoutineEnv_t *env = co->env;

	co_yield_env( env );

	return 0;
}



struct stCoRoutine_t *co_create_env( stCoRoutineEnv_t * env, const stCoRoutineAttr_t* attr,
		pfn_co_routine_t pfn,void *arg )
{

	stCoRoutineAttr_t at;
	if( attr )
	{
		memcpy( &at,attr,sizeof(at) );
	}
	if( at.stack_size <= 0 )
	{
		at.stack_size = 128 * 1024;
	}
	else if( at.stack_size > 1024 * 1024 * 8 )
	{
		at.stack_size = 1024 * 1024 * 8;
	}

	if( at.stack_size & 0xFFF ) 
	{
		at.stack_size &= ~0xFFF;
		at.stack_size += 0x1000;
	}

	stCoRoutine_t *lp = (stCoRoutine_t*)malloc( sizeof(stCoRoutine_t) );
	
	memset( lp,0,(long)(sizeof(stCoRoutine_t))); 


	lp->env = env;
	lp->pfn = pfn;
	lp->arg = arg;

	stStackMem_t* stack_mem = NULL;
	if( at.share_stack )
	{
		stack_mem = co_get_stackmem( at.share_stack);
		at.stack_size = at.share_stack->stack_size;
	}
	else
	{
		stack_mem = co_alloc_stackmem(at.stack_size);
	}
	lp->stack_mem = stack_mem;

	lp->ctx.ss_sp = stack_mem->stack_buffer;
	lp->ctx.ss_size = at.stack_size;

	lp->cStart = 0;
	lp->cEnd = 0;
	lp->cIsMain = 0;
	lp->cEnableSysHook = 0;
	lp->cIsShareStack = at.share_stack != NULL;

	lp->save_size = 0;
	lp->save_buffer = NULL;

	return lp;
}
/*
功能：创建协程
参数：	ppco: stCoRoutine_t** 类型的指针。输出参数，co_create 内部会为新协程分配⼀个“协程控制块”，co 将指向这个分配的协程控制块。
		attr: stCoRoutineAttr_t 类型的指针。输⼊参数，用于指定要创建协程的属性，可为 NULL。实际上仅有两个属性：栈⼤小、指向共享栈的指针（使用共享栈模式）。
		void* (routine)(void):void* (*)(void ) 类型的函数指针，指向协程的任务函数，即启动这个协程后要完成什么样的任务。routine 类型为函数指针。
		arg: void 类型指针，传递给任务函数的参数，类似于 pthread 传递给线程的参数。调用 co_create 将协程创建出来后，这时候它还没有启动，也即是说我们传递的routine 函数还没有被调用。
*/
int co_create( stCoRoutine_t **ppco,const stCoRoutineAttr_t *attr,pfn_co_routine_t pfn,void *arg )
{
	if( !co_get_curr_thread_env() ) 
	{
		co_init_curr_thread_env();
	}
	stCoRoutine_t *co = co_create_env( co_get_curr_thread_env(), attr, pfn,arg );
	*ppco = co;
	return 0;
}
/*
任务结束后要记得调用co_free()或 co_release()销毁这个临时性的协程，否则将引起内存泄漏。
*/
void co_free( stCoRoutine_t *co )
{
    if (!co->cIsShareStack) 
    {    
        free(co->stack_mem->stack_buffer);
        free(co->stack_mem);
    }   
    free( co );
}
void co_release( stCoRoutine_t *co )
{
    co_free( co );
}

void co_swap(stCoRoutine_t* curr, stCoRoutine_t* pending_co);
/*
功能：在调用 co_create 创建协程返回成功后，调用 co_resume 函数启动协程,可以通过 resume 将 CPU 交给任意协程
参数：启动 co 指针指向的协程
*/
void co_resume( stCoRoutine_t *co )
{
	stCoRoutineEnv_t *env = co->env;
	stCoRoutine_t *lpCurrRoutine = env->pCallStack[ env->iCallStackSize - 1 ];//取当前协程控制块指针
	
	/*if分支：当且仅当协程是第一次启动时才会执行到。
	首次启动协程过程有点特殊，需要调用 coctx_make() 为新协程准备 context（为了让 co_swap() 内能跳转到协程的任务函数）
	并将 cStart 标志变量置 1。*/
	if( !co->cStart )
	{
		coctx_make( &co->ctx,(coctx_pfn_t)CoRoutineFunc,co,0 );
		co->cStart = 1;
	}
	env->pCallStack[ env->iCallStackSize++ ] = co;//将待启动的协程 co 压入 pCallStack 栈
	co_swap(lpCurrRoutine, co);					  //调用 co_swap() 切换到 co 指向的新协程上去执行
	/*
	co_swap() 不会就此返回，而是要这次 resume 的 co 协程主动yield 让出 CPU 时才会返回到 co_resume() 中来。
	值得指出的是，这里讲 co_swap() 不会就此返回，不是说这个函数就阻塞在这里等待 co 这个协程 yield 让出 CPU。
	实际上
	后面我们将会看到，co_swap() 内部已经切换了 CPU 执行上下文，奔着 co 协程的代码路径去执行了
	*/
}
/*
功能：协程的挂起, yield 给当前协程的调用者
参数：当前协程的调用者，调用者协程保存在 stCoRoutineEnv_t的 pCallStack 中，因此你只能 yield 给“env”
*/
void co_yield_env( stCoRoutineEnv_t *env )
{
	
	stCoRoutine_t *last = env->pCallStack[ env->iCallStackSize - 2 ];
	stCoRoutine_t *curr = env->pCallStack[ env->iCallStackSize - 1 ];

	env->iCallStackSize--;

	co_swap( curr, last);
}

void co_yield_ct()
{

	co_yield_env( co_get_curr_thread_env() );
}
void co_yield( stCoRoutine_t *co )
{
	co_yield_env( co->env );
}

void save_stack_buffer(stCoRoutine_t* occupy_co)//将occupy_co的有效栈内存保存到save_buffer中。
{
	///copy out
	stStackMem_t* stack_mem = occupy_co->stack_mem;
	int len = stack_mem->stack_bp - occupy_co->stack_sp;

	if (occupy_co->save_buffer)
	{
		free(occupy_co->save_buffer), occupy_co->save_buffer = NULL;
	}

	occupy_co->save_buffer = (char*)malloc(len); //malloc buf;
	occupy_co->save_size = len;

	memcpy(occupy_co->save_buffer, occupy_co->stack_sp, len);
}

void co_swap(stCoRoutine_t* curr, stCoRoutine_t* pending_co)
{
 	stCoRoutineEnv_t* env = co_get_curr_thread_env();

	//get curr stack sp
	char c;
	curr->stack_sp= &c;	//取当前栈顶

	if (!pending_co->cIsShareStack) //若没有使用share stack，就不存在抢地盘的问题。
	{	//见官方注释：for copy stack log lastco and nextco
		env->pending_co = NULL;	 //可能被人家抢了地盘（栈）的协程，没有occupy_co自然就没有被抢的协程
		env->occupy_co = NULL;   //当前占用栈的协程
	}
	else //occupy_co是原来share stack的所有者，pending要抢占share stack  (多个协程争抢同一块share stack)
	{
		env->pending_co = pending_co;//设置好pending_co，下文中会将env->pending_co的栈还原
		//get last occupy co on the same stack mem
		stCoRoutine_t* occupy_co = pending_co->stack_mem->occupy_co;//公共栈空间原来的所有者
		//（occupy_co初始化是NULL），第一次执行协程后这里就会把它变为自己。初始化后第一次拿到执行权栈不为空之后，它不再会是NULL。
		//set pending co to occupy thest stack mem;
		pending_co->stack_mem->occupy_co = pending_co; //不管之前是谁占用了这个地盘，pending都会抢占share stack

		env->occupy_co = occupy_co;	//记录下之前是谁在使用share stack
		
		//如果pending要抢占share stack 那原来的所有者
		if (occupy_co && occupy_co != pending_co)//有occupy_co并且不是自己
		{
			save_stack_buffer(occupy_co);//将occupy_co的栈中有效数据保存到occupy->save_buffer中
			//pending_co把occupy_co撵走之后就可以还原自己的栈空间了。
		}
	}
	
	//swap context
	coctx_swap(&(curr->ctx),&(pending_co->ctx));
	
	//stack buffer may be overwrite, so get again;		//why?难道可以多线程之间串？
	stCoRoutineEnv_t* curr_env = co_get_curr_thread_env();
	stCoRoutine_t* update_occupy_co =  curr_env->occupy_co;
	stCoRoutine_t* update_pending_co = curr_env->pending_co;
	
	if (update_occupy_co && update_pending_co && update_occupy_co != update_pending_co)
	{
		//resume stack buffer
		if (update_pending_co->save_buffer && update_pending_co->save_size > 0)
		{
			memcpy(update_pending_co->stack_sp, update_pending_co->save_buffer, update_pending_co->save_size);
		}//pending抢占share stack
	}
}



//int poll(struct pollfd fds[], nfds_t nfds, int timeout);
// { fd,events,revents }
struct stPollItem_t ;
struct stPoll_t : public stTimeoutItem_t 
{
	struct pollfd *fds;
	nfds_t nfds; // typedef unsigned long int nfds_t;

	stPollItem_t *pPollItems;

	int iAllEventDetach;

	int iEpollFd;

	int iRaiseCnt;


};
struct stPollItem_t : public stTimeoutItem_t
{
	struct pollfd *pSelf;
	stPoll_t *pPoll;

	struct epoll_event stEvent;
};
/*
 *   EPOLLPRI 		POLLPRI    // There is urgent data to read.  
 *   EPOLLMSG 		POLLMSG
 *
 *   				POLLREMOVE
 *   				POLLRDHUP
 *   				POLLNVAL
 *
 * */
static uint32_t PollEvent2Epoll( short events )
{
	uint32_t e = 0;	
	if( events & POLLIN ) 	e |= EPOLLIN;
	if( events & POLLOUT )  e |= EPOLLOUT;
	if( events & POLLHUP ) 	e |= EPOLLHUP;
	if( events & POLLERR )	e |= EPOLLERR;
	if( events & POLLRDNORM ) e |= EPOLLRDNORM;
	if( events & POLLWRNORM ) e |= EPOLLWRNORM;
	return e;
}
static short EpollEvent2Poll( uint32_t events )
{
	short e = 0;	
	if( events & EPOLLIN ) 	e |= POLLIN;
	if( events & EPOLLOUT ) e |= POLLOUT;
	if( events & EPOLLHUP ) e |= POLLHUP;
	if( events & EPOLLERR ) e |= POLLERR;
	if( events & EPOLLRDNORM ) e |= POLLRDNORM;
	if( events & EPOLLWRNORM ) e |= POLLWRNORM;
	return e;
}

static stCoRoutineEnv_t* g_arrCoEnvPerThread[ 204800 ] = { 0 };
void co_init_curr_thread_env()
{
	pid_t pid = GetPid();	
	g_arrCoEnvPerThread[ pid ] = (stCoRoutineEnv_t*)calloc( 1,sizeof(stCoRoutineEnv_t) );
	stCoRoutineEnv_t *env = g_arrCoEnvPerThread[ pid ];

	env->iCallStackSize = 0;
	struct stCoRoutine_t *self = co_create_env( env, NULL, NULL,NULL );
	self->cIsMain = 1;

	env->pending_co = NULL;
	env->occupy_co = NULL;

	coctx_init( &self->ctx );

	env->pCallStack[ env->iCallStackSize++ ] = self;

	stCoEpoll_t *ev = AllocEpoll();
	SetEpoll( env,ev );
}
stCoRoutineEnv_t *co_get_curr_thread_env()
{
	return g_arrCoEnvPerThread[ GetPid() ];
}

void OnPollProcessEvent( stTimeoutItem_t * ap )
{
	stCoRoutine_t *co = (stCoRoutine_t*)ap->pArg;
	co_resume( co );
}

void OnPollPreparePfn( stTimeoutItem_t * ap,struct epoll_event &e,stTimeoutItemLink_t *active )
{//这个函数看上去像一种准备。
	stPollItem_t *lp = (stPollItem_t *)ap;
	lp->pSelf->revents = EpollEvent2Poll( e.events );
//pSelf是struct pollfd，revents是实际发生的事件（在poll调用里是由内核填充），

	stPoll_t *pPoll = lp->pPoll;
	pPoll->iRaiseCnt++;

	if( !pPoll->iAllEventDetach )
	{
		pPoll->iAllEventDetach = 1;//不可重入

		RemoveFromLink<stTimeoutItem_t,stTimeoutItemLink_t>( pPoll );//将本事件从链表中摘下。

		AddTail( active,pPoll );//摘下后放入active链表中。

	}
}

/*
功能：主协程事件循环
首先分配co_epoll_res结构用于epoll_wait。
根据epoll_wait返回的事件，获取对应stTimeoutItem_t对象
若定义了pfnPrepare函数，调用，否则，将item加入active链表之中。
接下来，获取当前时间，转动时间轮盘，获取所有超时的item，将他们加入timeout链表
设置超时flag为true。将timeout链表中所有元素加入active链表之中。
遍历active链表，没有超时的加入时间轮，调用每个结点的pfnProcess函数，唤醒对应协程。

*/
void co_eventloop( stCoEpoll_t *ctx,pfn_co_eventloop_t pfn,void *arg )
{
	if( !ctx->result )
	{
		ctx->result =  co_epoll_res_alloc( stCoEpoll_t::_EPOLL_SIZE );
	}
	co_epoll_res *result = ctx->result;


	for(;;)
	{
		int ret = co_epoll_wait( ctx->iEpollFd,result,stCoEpoll_t::_EPOLL_SIZE, 1 );//调用 epoll_wait() 等待 I/O 就绪事件，为了配合时间轮⼯作，这里的 timeout设置为 1 毫秒。

		stTimeoutItemLink_t *active = (ctx->pstActiveList);//active 指针指向当前执⾏环境的 pstActiveList 队列，注意这里面可能已经有“活跃”的待处理事件
		stTimeoutItemLink_t *timeout = (ctx->pstTimeoutList);//timeout 指针指向 pstTimeoutList 列表，其实这个 timeout 全是个临时性的链表

		memset( timeout,0,sizeof(stTimeoutItemLink_t) );
		
		//处理就绪的⽂件描述符
		for(int i=0;i<ret;i++)
		{
			stTimeoutItem_t *item = (stTimeoutItem_t*)result->events[i].data.ptr;
			if( item->pfnPrepare )
			{
				item->pfnPrepare( item,result->events[i],active );//如果用户设置了预处理回调，则调用pfnPrepare 做预处理,实际上，pfnPrepare() 预处理函数内部也会将就绪 item 加⼊ active 队列
			}
			else
			{
				AddTail( active,item );//否则直接将就绪事件 item 加⼊ active 队列
			}
		}

		//从时间轮上取出已超时的事件，放到 timeout 队列
		unsigned long long now = GetTickMS();
		TakeAllTimeout( ctx->pTimeout,now,timeout );
		//遍历 active 队列，调用⼯作协程设置的 pfnProcess() 回调函数 resume挂起的⼯作协程，处理对应的 I/O 或超时事件。这就是主协程的事件循环工作过程
		stTimeoutItem_t *lp = timeout->head;
		while( lp )
		{
			//printf("raise timeout %p\n",lp);
			lp->bTimeout = true;
			lp = lp->pNext;
		}

		Join<stTimeoutItem_t,stTimeoutItemLink_t>( active,timeout );

		lp = active->head;
		while( lp )
		{

			PopHead<stTimeoutItem_t,stTimeoutItemLink_t>( active );
            if (lp->bTimeout && now < lp->ullExpireTime) 
			{
				int ret = AddTimeout(ctx->pTimeout, lp, now);
				if (!ret) 
				{
					lp->bTimeout = false;
					lp = active->head;
					continue;
				}
			}
			if( lp->pfnProcess )
			{
				lp->pfnProcess( lp );
			}

			lp = active->head;
		}
		if( pfn )
		{
			if( -1 == pfn( arg ) )
			{
				break;
			}
		}

	}
}
void OnCoroutineEvent( stTimeoutItem_t * ap )
{
	stCoRoutine_t *co = (stCoRoutine_t*)ap->pArg;
	co_resume( co );
}


stCoEpoll_t *AllocEpoll()
{
	stCoEpoll_t *ctx = (stCoEpoll_t*)calloc( 1,sizeof(stCoEpoll_t) );

	ctx->iEpollFd = co_epoll_create( stCoEpoll_t::_EPOLL_SIZE );
	ctx->pTimeout = AllocTimeout( 60 * 1000 );
	
	ctx->pstActiveList = (stTimeoutItemLink_t*)calloc( 1,sizeof(stTimeoutItemLink_t) );
	ctx->pstTimeoutList = (stTimeoutItemLink_t*)calloc( 1,sizeof(stTimeoutItemLink_t) );


	return ctx;
}

void FreeEpoll( stCoEpoll_t *ctx )
{
	if( ctx )
	{
		free( ctx->pstActiveList );
		free( ctx->pstTimeoutList );
		FreeTimeout( ctx->pTimeout );
		co_epoll_res_free( ctx->result );
	}
	free( ctx );
}

stCoRoutine_t *GetCurrCo( stCoRoutineEnv_t *env )
{
	return env->pCallStack[ env->iCallStackSize - 1 ];
}
stCoRoutine_t *GetCurrThreadCo( )
{
	stCoRoutineEnv_t *env = co_get_curr_thread_env();
	if( !env ) return 0;
	return GetCurrCo(env);
}



typedef int (*poll_pfn_t)(struct pollfd fds[], nfds_t nfds, int timeout);
/*
co_poll_inner函数主要有三个作用：
1. 将poll的相关事件转换为epoll相关事件，并注册到当前线程的epoll中。
2. 注册超时事件，到当前的epoll中
3. 调用co_yield_ct, 让出该协程。
*/
int co_poll_inner( stCoEpoll_t *ctx,struct pollfd fds[], nfds_t nfds, int timeout, poll_pfn_t pollfunc)
{
    if (timeout == 0)
	{
		return pollfunc(fds, nfds, timeout);
	}
	if (timeout < 0)
	{
		timeout = INT_MAX;
	}
	int epfd = ctx->iEpollFd;	
	stCoRoutine_t* self = co_self();

	//1.struct change
	stPoll_t& arg = *((stPoll_t*)malloc(sizeof(stPoll_t)));	//stPoll_t结构体
	//以下代码为stPoll_t结构体初始化。这里代码作者使用的是引用&（感觉这个源码风格不统一可能是多人协作）
	memset( &arg,0,sizeof(arg) );

	arg.iEpollFd = epfd;//来自定时器
	arg.fds = (pollfd*)calloc(nfds, sizeof(pollfd));//struct pollfd 申请了nfds个
	arg.nfds = nfds;

	stPollItem_t arr[2]; //临时内存池，不一定会使用到它，（取栈内存比向os申请快得多）。
	if( nfds < sizeof(arr) / sizeof(arr[0]) && !self->cIsShareStack) 
	{//第一个条件判断了一下数组开的是不是够大，第二个条件检查share Stack的许可。
		//（这里为什么要检查share shack许可啊？难道是因为arr无法持久？）
		arg.pPollItems = arr;//若够大且允许，就使用数组。
	}	
	else//否则还是老老实实地跟os申请
	{
		arg.pPollItems = (stPollItem_t*)malloc( nfds * sizeof( stPollItem_t ) );
	}//pPollItems最终结果是指向了恰好是nfds*sizeof(stPollItem_t)大小的连续内存
	memset( arg.pPollItems,0,nfds * sizeof(stPollItem_t) );//内存清零  还是初始化

	arg.pfnProcess = OnPollProcessEvent;
	//pfnProcess是定时器成员，OnPollProcessEvent函数指针，此函数作用是将ap中pArg保存的stCoRoutine_t*取出，赋予执行权。（回到本函数）
	arg.pArg = GetCurrCo( co_get_curr_thread_env() );
	//上面两句使eventloop可以很容易定位并回到co_poll_inner继续执行。
	
	
	//2. add epoll
	for(nfds_t i=0;i<nfds;i++)//epoll的处理
	{
		arg.pPollItems[i].pSelf = arg.fds + i;//取第i个struct pollfd，就是pSelf
		arg.pPollItems[i].pPoll = &arg;

		arg.pPollItems[i].pfnPrepare = OnPollPreparePfn;//准备函数。
		struct epoll_event &ev = arg.pPollItems[i].stEvent;

		if( fds[i].fd > -1 )
		{
			ev.data.ptr = arg.pPollItems + i;
			ev.events = PollEvent2Epoll( fds[i].events );//co_poll用的事件类型转为epoll用的类型。

			int ret = co_epoll_ctl( epfd,EPOLL_CTL_ADD, fds[i].fd, &ev );
			if (ret < 0 && errno == EPERM && nfds == 1 && pollfunc != NULL)
			{
				if( arg.pPollItems != arr )
				{
					free( arg.pPollItems );
					arg.pPollItems = NULL;
				}
				free(arg.fds);
				free(&arg);
				return pollfunc(fds, nfds, timeout);
			}
		}
		//if fail,the timeout would work
	}

	//3.add timeout

	unsigned long long now = GetTickMS();
	arg.ullExpireTime = now + timeout;//设置超时时间点。
	int ret = AddTimeout( ctx->pTimeout,&arg,now );//往时间轮中加计时器
	int iRaiseCnt = 0;
	if( ret != 0 ) //错误处理一下。
	{
		co_log_err("CO_ERR: AddTimeout ret %d now %lld timeout %d arg.ullExpireTime %lld",
				ret,now,timeout,arg.ullExpireTime);
		errno = EINVAL;
		iRaiseCnt = -1;

	}
    else
	{
		co_yield_env( co_get_curr_thread_env() );
	    //交出执行权，这里会等待eventloop被调用，由eventloop将co_poll事件处理完毕会重新将执行权归还本函数。
		iRaiseCnt = arg.iRaiseCnt;
	}

    {//收尾工作。
		//clear epoll status and memory
		RemoveFromLink<stTimeoutItem_t,stTimeoutItemLink_t>( &arg );
		for(nfds_t i = 0;i < nfds;i++)
		{
			int fd = fds[i].fd;
			if( fd > -1 )
			{
				co_epoll_ctl( epfd,EPOLL_CTL_DEL,fd,&arg.pPollItems[i].stEvent );
			}//del
			fds[i].revents = arg.fds[i].revents;
		}


		if( arg.pPollItems != arr )
		{
			free( arg.pPollItems );
			arg.pPollItems = NULL;
		}

		free(arg.fds);
		free(&arg);
	}

	return iRaiseCnt;
}

int	co_poll( stCoEpoll_t *ctx,struct pollfd fds[], nfds_t nfds, int timeout_ms )
{
	return co_poll_inner(ctx, fds, nfds, timeout_ms, NULL);
}

void SetEpoll( stCoRoutineEnv_t *env,stCoEpoll_t *ev )
{
	env->pEpoll = ev;
}
stCoEpoll_t *co_get_epoll_ct()
{
	if( !co_get_curr_thread_env() )
	{
		co_init_curr_thread_env();
	}
	return co_get_curr_thread_env()->pEpoll;
}
struct stHookPThreadSpec_t
{
	stCoRoutine_t *co;
	void *value;

	enum 
	{
		size = 1024
	};
};
void *co_getspecific(pthread_key_t key)
{
	stCoRoutine_t *co = GetCurrThreadCo();
	if( !co || co->cIsMain )
	{
		return pthread_getspecific( key );
	}
	return co->aSpec[ key ].value;
}
int co_setspecific(pthread_key_t key, const void *value)
{
	stCoRoutine_t *co = GetCurrThreadCo();
	if( !co || co->cIsMain )
	{
		return pthread_setspecific( key,value );
	}
	co->aSpec[ key ].value = (void*)value;
	return 0;
}



void co_disable_hook_sys()
{
	stCoRoutine_t *co = GetCurrThreadCo();
	if( co )
	{
		co->cEnableSysHook = 0;
	}
}
bool co_is_enable_sys_hook()
{
	stCoRoutine_t *co = GetCurrThreadCo();
	return ( co && co->cEnableSysHook );
}

stCoRoutine_t *co_self()
{
	return GetCurrThreadCo();
}

//co cond
struct stCoCond_t;
struct stCoCondItem_t 
{
	stCoCondItem_t *pPrev;
	stCoCondItem_t *pNext;
	stCoCond_t *pLink;

	stTimeoutItem_t timeout;
};
struct stCoCond_t
{
	stCoCondItem_t *head;
	stCoCondItem_t *tail;
};
static void OnSignalProcessEvent( stTimeoutItem_t * ap )
{
	stCoRoutine_t *co = (stCoRoutine_t*)ap->pArg;
	co_resume( co );
}

stCoCondItem_t *co_cond_pop( stCoCond_t *link );
int co_cond_signal( stCoCond_t *si )
{
	stCoCondItem_t * sp = co_cond_pop( si );
	if( !sp ) 
	{
		return 0;
	}
	RemoveFromLink<stTimeoutItem_t,stTimeoutItemLink_t>( &sp->timeout );

	AddTail( co_get_curr_thread_env()->pEpoll->pstActiveList,&sp->timeout );

	return 0;
}
int co_cond_broadcast( stCoCond_t *si )
{
	for(;;)
	{
		stCoCondItem_t * sp = co_cond_pop( si );
		if( !sp ) return 0;

		RemoveFromLink<stTimeoutItem_t,stTimeoutItemLink_t>( &sp->timeout );

		AddTail( co_get_curr_thread_env()->pEpoll->pstActiveList,&sp->timeout );
	}

	return 0;
}


int co_cond_timedwait( stCoCond_t *link,int ms )
{
	stCoCondItem_t* psi = (stCoCondItem_t*)calloc(1, sizeof(stCoCondItem_t));
	psi->timeout.pArg = GetCurrThreadCo();
	psi->timeout.pfnProcess = OnSignalProcessEvent;

	if( ms > 0 )
	{
		unsigned long long now = GetTickMS();
		psi->timeout.ullExpireTime = now + ms;

		int ret = AddTimeout( co_get_curr_thread_env()->pEpoll->pTimeout,&psi->timeout,now );
		if( ret != 0 )
		{
			free(psi);
			return ret;
		}
	}
	AddTail( link, psi);

	co_yield_ct();


	RemoveFromLink<stCoCondItem_t,stCoCond_t>( psi );
	free(psi);

	return 0;
}
stCoCond_t *co_cond_alloc()
{
	return (stCoCond_t*)calloc( 1,sizeof(stCoCond_t) );
}
int co_cond_free( stCoCond_t * cc )
{
	free( cc );
	return 0;
}


stCoCondItem_t *co_cond_pop( stCoCond_t *link )
{
	stCoCondItem_t *p = link->head;
	if( p )
	{
		PopHead<stCoCondItem_t,stCoCond_t>( link );
	}
	return p;
}