C++定時(shí)器實(shí)現(xiàn)和時(shí)間輪介紹

更新時(shí)間：2022年09月15日 16:58:06 作者：今天也要寫bug、

這篇文章主要介紹了C++定時(shí)器實(shí)現(xiàn)和時(shí)間輪介紹，定時(shí)器可以由很多種數(shù)據(jù)結(jié)構(gòu)實(shí)現(xiàn)，比如最小堆、紅黑樹、跳表、甚至數(shù)組都可以，其本質(zhì)都是拿到最小時(shí)間的任務(wù)，然后取出該任務(wù)并執(zhí)行，更多相關(guān)內(nèi)容介紹，需要的小伙伴可以參考一下

定時(shí)器

有些時(shí)候我們需要延遲執(zhí)行一些功能，比如每10s進(jìn)行一次數(shù)據(jù)采集。或者告知用戶技能冷卻有多少時(shí)間，如果我們將執(zhí)行這些功能的任務(wù)交給主線程，就會(huì)造成主線程的阻塞。因此我們可以選擇一個(gè)創(chuàng)建一個(gè)子線程，讓其檢測(cè)定時(shí)器中的任務(wù)，當(dāng)有任務(wù)的時(shí)間到了的時(shí)候，就去執(zhí)行這個(gè)任務(wù)。

最小堆實(shí)現(xiàn)定時(shí)器

定時(shí)器可以由很多種數(shù)據(jù)結(jié)構(gòu)實(shí)現(xiàn)，比如最小堆、紅黑樹、跳表、甚至數(shù)組都可以，其本質(zhì)都是拿到最小時(shí)間的任務(wù)，然后取出該任務(wù)并執(zhí)行。
綜合實(shí)現(xiàn)難度和效率來(lái)看，最小堆是最容易實(shí)現(xiàn)定時(shí)器的數(shù)據(jù)結(jié)構(gòu)。

最小堆主要有以下接口：

#pragma once

#include <vector>
#include <map>
using namespace std;
typedef void (*TimerHandler)(struct TimerNode *node);
//獲取系統(tǒng)時(shí)間，單位是毫秒
static uint32_t current_time()
{
    uint32_t t;
    struct timespec ti;
    clock_gettime(CLOCK_MONOTONIC, &ti);
    t = (uint32_t)ti.tv_sec * 1000;
    t += ti.tv_nsec / 1000000;
    return t;
}
struct TimerNode
{
    //該任務(wù)在最小堆中的下標(biāo)位置
    int idx = 0;
    //該任務(wù)是第幾號(hào)任務(wù)
    int id = 0;
    //幾毫秒后執(zhí)行該任務(wù)
    unsigned int expire = 0;
    //回調(diào)函數(shù)
    TimerHandler cb = NULL;
};
class MinHeapTimer
{
public:
    MinHeapTimer()
    {
        _heap.clear();
        _map.clear();
    }
    int Count();
    //加入任務(wù)，expire為該任務(wù)的失效時(shí)間，expire過后就要執(zhí)行回調(diào)函數(shù)cb
    int AddTimer(uint32_t expire, TimerHandler cb);
    //刪除一個(gè)任務(wù)
    bool DelTimer(int id);
    //獲取一個(gè)任務(wù)
    void ExpireTimer();
private:
    //用于比較兩個(gè)任務(wù)的過期時(shí)間
    bool _compare(int lhs, int rhs);
    //向下調(diào)整算法，每次刪除一個(gè)節(jié)點(diǎn)就要向下調(diào)整
    void _shiftDown(int parent);
    //向上調(diào)整算法，每添加一個(gè)數(shù)都要調(diào)用向上調(diào)整算法，保證根節(jié)點(diǎn)為最小節(jié)點(diǎn)
    void _shiftUp(int child);
    //刪除的子函數(shù)
    void _delNode(TimerNode *node);
    void resign(int pos);
private:
    //數(shù)組中存儲(chǔ)任務(wù)節(jié)點(diǎn)
    vector<TimerNode *> _heap;
    //存儲(chǔ)值和響應(yīng)節(jié)點(diǎn)的映射關(guān)系
    map<int, TimerNode *> _map;
    //任務(wù)的個(gè)數(shù)，注意不是_heap的size
    int _count = 0;
};

具體的實(shí)現(xiàn)以及測(cè)試為：

#pragma once
#include <vector>
#include <map>
using namespace std;
typedef void (*TimerHandler)(struct TimerNode *node);
//獲取系統(tǒng)時(shí)間，單位是毫秒
static uint32_t current_time()
{
    uint32_t t;
    struct timespec ti;
    clock_gettime(CLOCK_MONOTONIC, &ti);
    t = (uint32_t)ti.tv_sec * 1000;
    t += ti.tv_nsec / 1000000;
    return t;
}
struct TimerNode
{
    //該任務(wù)在最小堆中的下標(biāo)位置
    int idx = 0;
    //該任務(wù)是第幾號(hào)任務(wù)
    int id = 0;
    unsigned int expire = 0;
    //回調(diào)函數(shù)
    TimerHandler cb = NULL;
};

class MinHeapTimer
{
public:
    MinHeapTimer()
    {
        _heap.clear();
        _map.clear();
    }
    int Count()
    {
        return ++_count;
    }
    //加入任務(wù)，expire為該任務(wù)的失效時(shí)間，expire過后就要執(zhí)行回調(diào)函數(shù)cb
    int AddTimer(uint32_t expire, TimerHandler cb)
    {
        int64_t timeout = current_time() + expire;
        TimerNode *node = new TimerNode;
        int id = Count();
        node->id = id;
        node->expire = timeout;
        node->cb = cb;
        node->idx = (int)_heap.size();
        _heap.push_back(node);
        _shiftUp((int)_heap.size() - 1);
        _map.insert(make_pair(id, node));
        return id;
    }
    //刪除一個(gè)任務(wù)
    bool DelTimer(int id)
    {
        auto iter = _map.find(id);
        if (iter == _map.end())
            return false;
        _delNode(iter->second);
        return true;
    }
    //獲取一個(gè)任務(wù)
    void ExpireTimer()
    {
        if (_heap.empty())
        {
            return;
        }
        //獲取當(dāng)前時(shí)間
        uint32_t now = current_time();
        while (!_heap.empty())
        {
            //獲取最近的一個(gè)任務(wù)
            TimerNode *node = _heap.front();
            //當(dāng)最近一個(gè)任務(wù)的時(shí)間大于當(dāng)前時(shí)間，說明沒有任務(wù)要執(zhí)行
            if (now < node->expire)
            {
                break;
            }
            //遍歷一下堆，這一步可以不加
            for (int i = 0; i < _heap.size(); i++)
            {
                std::cout << "touch    idx: " << _heap[i]->idx
                          << " id: " << _heap[i]->id << " expire: "
                          << _heap[i]->expire << std::endl;
            }
            //執(zhí)行最近任務(wù)的回調(diào)函數(shù)
            if (node->cb)
            {
                node->cb(node);
            }
            //執(zhí)行完就刪掉這個(gè)任務(wù)
            _delNode(node);
        }
    }
private:
    //用于比較兩個(gè)任務(wù)的過期時(shí)間
    bool _compare(int lhs, int rhs)
    {
        return _heap[lhs]->expire < _heap[rhs]->expire;
    }
    //向下調(diào)整算法，每次刪除一個(gè)節(jié)點(diǎn)就要向下調(diào)整
    void _shiftDown(int parent)
    {
        int child = parent * 2 + 1;
        while (child < _heap.size() - 1)
        {
            if (child + 1 < _heap.size() - 1 && !_compare(child, child + 1))
            {
                child++;
            }
            if (!_compare(parent, child))
            {
                std::swap(_heap[parent], _heap[child]);
                _heap[parent]->idx = parent;
                _heap[child]->idx = child;
                parent = child;
                child = parent * 2 + 1;
            }
            else
            {
                break;
            }
        }
    }
    //向上調(diào)整算法，每添加一個(gè)數(shù)都要調(diào)用向上調(diào)整算法，保證根節(jié)點(diǎn)為最小節(jié)點(diǎn)
    void _shiftUp(int child)
    {
        int parent = (child - 1) / 2;
        while (child > 0)
        {
            if (!_compare(parent, child))
            {
                std::swap(_heap[parent], _heap[child]);
                _heap[parent]->idx = parent;
                _heap[child]->idx = child;
                child = parent;
                parent = (child - 1) / 2;
            }
            else
            {
                break;
            }
        }
    }
    //刪除的子函數(shù)
    void _delNode(TimerNode *node)
    {
        int last = (int)_heap.size() - 1;
        int idx = node->idx;
        if (idx != last)
        {
            std::swap(_heap[idx], _heap[last]);
            _heap[idx]->idx = idx;
            resign(idx);
        }
        _heap.pop_back();
        _map.erase(node->id);
        delete node;
    }
    void resign(int pos)
    {
        //向上調(diào)整和向下調(diào)整只會(huì)發(fā)生一個(gè)
        _shiftDown(pos);
        _shiftUp(pos);
    }
private:
    //數(shù)組中存儲(chǔ)任務(wù)節(jié)點(diǎn)
    vector<TimerNode *> _heap;
    //存儲(chǔ)值和響應(yīng)節(jié)點(diǎn)的映射關(guān)系
    map<int, TimerNode *> _map;
    //任務(wù)的個(gè)數(shù)，注意不是_heap的size
    int _count = 0;
};

#include <time.h>
#include <unistd.h>
#include <iostream>
#include "minheap.h"
void print_hello(TimerNode *te)
{
    std::cout << "hello world time = " << te->idx << "\t" << te->id << "\t" << current_time() << std::endl;
}
int main()
{
    MinHeapTimer mht;
    //一號(hào)任務(wù)，立刻執(zhí)行
    mht.AddTimer(0, print_hello);
    //二號(hào)任務(wù)，一秒后執(zhí)行
    mht.AddTimer(1000, print_hello);
    mht.AddTimer(7000, print_hello);
    mht.AddTimer(2000, print_hello);
    mht.AddTimer(9000, print_hello);
    mht.AddTimer(10000, print_hello);
    mht.AddTimer(6000, print_hello);
    mht.AddTimer(3000, print_hello);
    while (1)
    {
        mht.ExpireTimer();
        // usleep(10000);
        sleep(1);
    }
    return 0;
}

時(shí)間輪

上面的定時(shí)器在任務(wù)數(shù)量很多時(shí)，效率會(huì)很低，因?yàn)槲覀冃枰米钚《褋?lái)維護(hù)這些任務(wù)，并且每刪除一個(gè)任務(wù)，都要進(jìn)行調(diào)整。其主要原因是我們不知道其他任務(wù)什么時(shí)候執(zhí)行，所以我們只能進(jìn)行調(diào)整，將最近的任務(wù)放到堆頂。

如果我們能夠向哈希桶那樣，將要執(zhí)行的任務(wù)形成鏈表，掛到要執(zhí)行的位置，當(dāng)時(shí)間走到那個(gè)位置的時(shí)候，就執(zhí)行這些任務(wù)，效率豈不是更高？

單層級(jí)時(shí)間輪

客戶端每 5 秒鐘發(fā)送?跳包；服務(wù)端若 10 秒內(nèi)沒收到?跳數(shù)據(jù)，則清除連接。

考慮到正常情況下 5 秒鐘發(fā)送?次?跳包，10 秒才檢測(cè)?次，如下圖到索引為 10 的時(shí)候并不能踢掉連接；所以需要每收到?次?跳包則 used++ ，每檢測(cè)?次 used-- ；當(dāng)檢測(cè)到used == 0 則踢掉連接；

#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <sys/time.h>
#include <time.h>
#define MAX_CONN ((1 << 16) - 1)
//連接的節(jié)點(diǎn)，用來(lái)記錄心跳包發(fā)送的次數(shù)
typedef struct conn_node
{
    struct conn_node *next;
    //引用計(jì)數(shù)的次數(shù),當(dāng)used==0，相當(dāng)于自動(dòng)銷毀
    uint8_t used;
    int id;
} conn_node_t;
//用數(shù)組記錄所有的連接
static conn_node_t nodes[MAX_CONN] = {0};
static uint32_t iter = 0;
//獲取一個(gè)空的連接節(jié)點(diǎn)
conn_node_t *get_node()
{
    iter++;
    while (nodes[iter & MAX_CONN].used > 0)
    {
        iter++;
    }
    return &nodes[iter];
}
//哈希桶的個(gè)數(shù)
#define TW_SIZE 16
//檢測(cè)心跳包的延遲時(shí)間，由于哈希桶的個(gè)數(shù)有限，所以心跳包發(fā)送時(shí)間不能夠超過6
#define EXPIRE 10
//取余操作
#define TW_MASK (TW_SIZE - 1)
static uint32_t tick = 0;
//哈希桶
typedef struct link_list
{
    conn_node_t head;
    //一個(gè)tail，能夠進(jìn)行快速插入
    conn_node_t *tail;
} link_list_t;
//添加連接
void add_conn(link_list_t *tw, conn_node_t *node, int delay)
{
    //獲取對(duì)應(yīng)的哈希桶
    link_list_t *list = &tw[(tick + EXPIRE + delay) & TW_MASK];
    list->tail->next = node;
    list->tail = node;
    node->next = NULL;
    node->used++;
}
//清楚這個(gè)哈希桶
void link_clear(link_list_t *list)
{
    list->head.next = NULL;
    list->tail = &(list->head);
}
//檢測(cè)哈希桶
void check_conn(link_list_t *tw)
{
    int32_t itick = tick;
    tick++;
    //取到對(duì)應(yīng)哈希桶的鏈表
    link_list_t *list = &tw[itick & TW_MASK];
    //檢測(cè)哈希桶對(duì)應(yīng)的鏈表
    conn_node_t *current = list->head.next;
    while (current)
    {
        conn_node_t *temp = current;
        current = current->next;
        temp->used--;

        if (temp->used == 0)
        {
            printf("連接:%d 斷開\n", temp->id);
            temp->next = NULL;
            continue;
        }
        printf("這個(gè)鏈接:%d 心跳包還剩:%d個(gè)需要檢測(cè)\n", temp->id, temp->used);
    }
    link_clear(list);
}
//獲取時(shí)間，單位是s
static time_t current_time()
{
    time_t t;
    struct timespec ti;
    clock_gettime(CLOCK_MONOTONIC, &ti);
    t = (time_t)ti.tv_sec;
    return t;
}
int main()
{
    memset(nodes, 0, MAX_CONN * sizeof(conn_node_t));

    // init link list
    link_list_t tw[TW_SIZE];
    memset(tw, 0, TW_SIZE * sizeof(link_list_t));
    for (int i = 0; i < TW_SIZE; i++)
    {
        link_clear(&tw[i]);
    }
    // 第一個(gè)連接對(duì)應(yīng)的心跳包，在0和5時(shí)進(jìn)行發(fā)送
    //所以會(huì)在10s和15s時(shí)進(jìn)行檢測(cè)，15s時(shí)把該連接斷開
    {
        conn_node_t *node = get_node();
        node->id = 10001;
        add_conn(tw, node, 0);
        add_conn(tw, node, 5);
    }
    //第二個(gè)連接發(fā)送的心跳包，在第10s時(shí)進(jìn)行檢測(cè)
    {
        conn_node_t *node = get_node();
        node->id = 10002;
        add_conn(tw, node, 0);
    }
    //第二個(gè)連接發(fā)送的心跳包，在第13s時(shí)檢測(cè)
    {
        conn_node_t *node = get_node();
        node->id = 10003;
        add_conn(tw, node, 3);
    }
    time_t start = current_time();
    while (1)
    {
        time_t now = current_time();
        if (now - start > 0)
        {
            for (int i = 0; i < now - start; i++)
                check_conn(tw);
            start = now;
            printf("在第%d秒時(shí)檢測(cè),此時(shí)機(jī)器時(shí)間:%d\n", tick, now);
        }
    }
    return 0;
}

上面的時(shí)間輪受哈希桶大小和延遲10s收到心跳包的影響，只能在[0,6]秒內(nèi)發(fā)送數(shù)據(jù)心跳包，如果想要延遲長(zhǎng)時(shí)間，則需要擴(kuò)大哈希桶的大小。

如果我們不發(fā)送心跳包，而是改成在若干秒后執(zhí)行一個(gè)任務(wù)，比如50s后執(zhí)行任務(wù)，但哈希桶大小只有16，我們可以在任務(wù)節(jié)點(diǎn)中增加一個(gè)參數(shù)round，用來(lái)記錄需要走多少遍哈希桶，比如50s，對(duì)應(yīng)到大小為16的哈希桶則round=3,idx=2。
不過這樣做，在check_conn取任務(wù)時(shí)就不能夠把整個(gè)鏈表都取出來(lái)，而是需要取出round==0的任務(wù)。

typedef struct node
{
    struct conn_node *next;
    //需要走多少輪哈希桶，當(dāng)round==0時(shí)，則說明需要執(zhí)行這個(gè)任務(wù)
    int round;
    int id;
} node_t;

這樣做能解決時(shí)間輪刻度范圍過大造成的空間浪費(fèi)，但是卻帶來(lái)了另一個(gè)問題：時(shí)間輪每次都需要遍歷任務(wù)列表，耗時(shí)增加，當(dāng)時(shí)間輪刻度粒度很小(秒級(jí)甚至毫秒級(jí))，任務(wù)列表又特別長(zhǎng)時(shí)，這種遍歷的辦法是不可接受的。

多層級(jí)時(shí)間輪

參照時(shí)鐘表盤的運(yùn)轉(zhuǎn)規(guī)律，可以將定時(shí)任務(wù)根據(jù)觸發(fā)的緊急程度，分布到不同層級(jí)的時(shí)間輪中；
假設(shè)時(shí)間精度為 10ms ；在第 1 層級(jí)每 10ms 移動(dòng)?格；每移動(dòng)?格執(zhí)?該格?當(dāng)中所有的定時(shí)任務(wù)；
當(dāng)?shù)?1 層指針從 255 格開始移動(dòng)，此時(shí)層級(jí) 2 移動(dòng)?格；層級(jí) 2 移動(dòng)?格的?為定義為，將該格當(dāng)中的定時(shí)任務(wù)重新映射到層級(jí) 1 當(dāng)中；同理，層級(jí) 2 當(dāng)中從 63 格開始移動(dòng)，層級(jí) 3 格?中的定時(shí)任務(wù)重新映射到層級(jí) 2 ; 以此類推層級(jí) 4 往層級(jí) 3 映射，層級(jí) 5 往層級(jí) 4 映射。
只有任務(wù)在第一層時(shí)才會(huì)被執(zhí)行，其他層都是將任務(wù)重新映射到上一層。

timewheel.h:

#pragma once

#include <stdint.h>
#define TIME_NEAR_SHIFT 8
#define TIME_NEAR (1 << TIME_NEAR_SHIFT)
#define TIME_LEVEL_SHIFT 6
#define TIME_LEVEL (1 << TIME_LEVEL_SHIFT)
#define TIME_NEAR_MASK (TIME_NEAR - 1)
#define TIME_LEVEL_MASK (TIME_LEVEL - 1)
typedef struct timer_node timer_node_t;
typedef void (*handler_pt)(struct timer_node *node);
struct timer_node
{
	struct timer_node *next;
	uint32_t expire;	 //時(shí)間
	handler_pt callback; //回調(diào)函數(shù)
	uint8_t cancel;		 //是否刪除
	int id;				 // 此時(shí)攜帶參數(shù)
};
timer_node_t *add_timer(int time, handler_pt func, int threadid);
void expire_timer(void);
void del_timer(timer_node_t *node);
void init_timer(void);
void clear_timer();

spinlock.h:

#pragma once
struct spinlock
{
	int lock;
};
void spinlock_init(struct spinlock *lock)
{
	lock->lock = 0;
}
void spinlock_lock(struct spinlock *lock)
{
	while (__sync_lock_test_and_set(&lock->lock, 1))
	{
	}
}
int spinlock_trylock(struct spinlock *lock)
{
	return __sync_lock_test_and_set(&lock->lock, 1) == 0;
}
void spinlock_unlock(struct spinlock *lock)
{
	__sync_lock_release(&lock->lock);
}
void spinlock_destroy(struct spinlock *lock)
{
	(void)lock;
}

timewheel.cpp:

#include "spinlock.h"
#include "timewheel.h"
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <time.h>
typedef struct link_list
{
	timer_node_t head;
	timer_node_t *tail;
} link_list_t;

//多級(jí)時(shí)間輪
typedef struct timer
{
	//第一級(jí)
	link_list_t near[TIME_NEAR];
	// 2-4級(jí)
	link_list_t t[4][TIME_LEVEL];
	struct spinlock lock;
	uint32_t time;
	uint64_t current;
	uint64_t current_point;
} s_timer_t;
static s_timer_t *TI = NULL;
timer_node_t *link_clear(link_list_t *list)
{
	timer_node_t *ret = list->head.next;
	list->head.next = 0;
	list->tail = &(list->head);

	return ret;
}
//鏈接一個(gè)節(jié)點(diǎn)
void link(link_list_t *list, timer_node_t *node)
{
	list->tail->next = node;
	list->tail = node;
	node->next = 0;
}
void add_node(s_timer_t *T, timer_node_t *node)
{
	uint32_t time = node->expire;
	uint32_t current_time = T->time;
	uint32_t msec = time - current_time;
	//根據(jù)時(shí)間
	if (msec < TIME_NEAR)
	{ //[0, 0x100)
		link(&T->near[time & TIME_NEAR_MASK], node);
	}
	else if (msec < (1 << (TIME_NEAR_SHIFT + TIME_LEVEL_SHIFT)))
	{ //[0x100, 0x4000)
		link(&T->t[0][((time >> TIME_NEAR_SHIFT) & TIME_LEVEL_MASK)], node);
	}
	else if (msec < (1 << (TIME_NEAR_SHIFT + 2 * TIME_LEVEL_SHIFT)))
	{ //[0x4000, 0x100000)
		link(&T->t[1][((time >> (TIME_NEAR_SHIFT + TIME_LEVEL_SHIFT)) & TIME_LEVEL_MASK)], node);
	}
	else if (msec < (1 << (TIME_NEAR_SHIFT + 3 * TIME_LEVEL_SHIFT)))
	{ //[0x100000, 0x4000000)
		link(&T->t[2][((time >> (TIME_NEAR_SHIFT + 2 * TIME_LEVEL_SHIFT)) & TIME_LEVEL_MASK)], node);
	}
	else
	{ //[0x4000000, 0xffffffff]
		link(&T->t[3][((time >> (TIME_NEAR_SHIFT + 3 * TIME_LEVEL_SHIFT)) & TIME_LEVEL_MASK)], node);
	}
}
//增加事件
timer_node_t *add_timer(int time, handler_pt func, int threadid)
{
	timer_node_t *node = (timer_node_t *)malloc(sizeof(*node));
	spinlock_lock(&TI->lock);
	node->expire = time + TI->time; // 每10ms加1 0
	node->callback = func;
	node->id = threadid;
	if (time <= 0)
	{
		node->callback(node);
		free(node);
		spinlock_unlock(&TI->lock);
		return NULL;
	}
	add_node(TI, node);
	spinlock_unlock(&TI->lock);
	return node;
}
void move_list(s_timer_t *T, int level, int idx)
{
	timer_node_t *current = link_clear(&T->t[level][idx]);
	while (current)
	{
		timer_node_t *temp = current->next;
		add_node(T, current);
		current = temp;
	}
}
void timer_shift(s_timer_t *T)
{
	int mask = TIME_NEAR;
	uint32_t ct = ++T->time;
	if (ct == 0)
	{
		move_list(T, 3, 0);
	}
	else
	{
		// ct / 256
		uint32_t time = ct >> TIME_NEAR_SHIFT;
		int i = 0;
		// ct % 256 == 0
		while ((ct & (mask - 1)) == 0)
		{
			int idx = time & TIME_LEVEL_MASK;
			if (idx != 0)
			{
				move_list(T, i, idx);
				break;
			}
			mask <<= TIME_LEVEL_SHIFT;
			time >>= TIME_LEVEL_SHIFT;
			++i;
		}
	}
}
void dispatch_list(timer_node_t *current)
{
	do
	{
		timer_node_t *temp = current;
		current = current->next;
		if (temp->cancel == 0)
			temp->callback(temp);
		free(temp);
	} while (current);
}
void timer_execute(s_timer_t *T)
{
	int idx = T->time & TIME_NEAR_MASK;

	while (T->near[idx].head.next)
	{
		timer_node_t *current = link_clear(&T->near[idx]);
		spinlock_unlock(&T->lock);
		dispatch_list(current);
		spinlock_lock(&T->lock);
	}
}
void timer_update(s_timer_t *T)
{
	spinlock_lock(&T->lock);
	timer_execute(T);
	timer_shift(T);
	timer_execute(T);
	spinlock_unlock(&T->lock);
}

void del_timer(timer_node_t *node)
{
	node->cancel = 1;
}
s_timer_t *timer_create_timer()
{
	s_timer_t *r = (s_timer_t *)malloc(sizeof(s_timer_t));
	memset(r, 0, sizeof(*r));
	int i, j;
	for (i = 0; i < TIME_NEAR; i++)
	{
		link_clear(&r->near[i]);
	}
	for (i = 0; i < 4; i++)
	{
		for (j = 0; j < TIME_LEVEL; j++)
		{
			link_clear(&r->t[i][j]);
		}
	}
	spinlock_init(&r->lock);
	r->current = 0;
	return r;
}
uint64_t gettime()
{
	uint64_t t;
	struct timespec ti;
	clock_gettime(CLOCK_MONOTONIC, &ti);
	t = (uint64_t)ti.tv_sec * 100;
	t += ti.tv_nsec / 10000000;

	return t;
}
void expire_timer(void)
{
	uint64_t cp = gettime();
	if (cp != TI->current_point)
	{
		uint32_t diff = (uint32_t)(cp - TI->current_point);
		TI->current_point = cp;
		int i;
		for (i = 0; i < diff; i++)
		{
			timer_update(TI);
		}
	}
}
void init_timer(void)
{
	TI = timer_create_timer();
	TI->current_point = gettime();
}
void clear_timer()
{
	int i, j;
	for (i = 0; i < TIME_NEAR; i++)
	{
		link_list_t *list = &TI->near[i];
		timer_node_t *current = list->head.next;
		while (current)
		{
			timer_node_t *temp = current;
			current = current->next;
			free(temp);
		}
		link_clear(&TI->near[i]);
	}
	for (i = 0; i < 4; i++)
	{
		for (j = 0; j < TIME_LEVEL; j++)
		{
			link_list_t *list = &TI->t[i][j];
			timer_node_t *current = list->head.next;
			while (current)
			{
				timer_node_t *temp = current;
				current = current->next;
				free(temp);
			}
			link_clear(&TI->t[i][j]);
		}
	}
}

tw-timer.cpp:

#include <stdio.h>
#include <unistd.h>

#include <pthread.h>
#include <time.h>
#include <stdlib.h>
#include "timewheel.h"
struct context
{
    int quit;
    int thread;
};
struct thread_param
{
    struct context *ctx;
    int id;
};
static struct context ctx = {0};
void do_timer(timer_node_t *node)
{
    printf("timer expired:%d - thread-id:%d\n", node->expire, node->id);
}
void *thread_worker(void *p)
{
    struct thread_param *tp = (struct thread_param *)p;
    int id = tp->id;
    struct context *ctx = tp->ctx;
    while (!ctx->quit)
    {
        int expire = rand() % 200;
        add_timer(expire, do_timer, id);
        usleep(expire * (10 - 1) * 1000);
    }
    printf("thread_worker:%d exit!\n", id);
    return NULL;
}
void do_quit(timer_node_t *node)
{
    ctx.quit = 1;
}
int main()
{
    srand(time(NULL));
    ctx.thread = 8;
    pthread_t pid[ctx.thread];

    init_timer();
    add_timer(6000, do_quit, 100);
    struct thread_param task_thread_p[ctx.thread];
    int i;
    for (i = 0; i < ctx.thread; i++)
    {
        task_thread_p[i].id = i;
        task_thread_p[i].ctx = &ctx;
        if (pthread_create(&pid[i], NULL, thread_worker, &task_thread_p[i]))
        {
            fprintf(stderr, "create thread failed\n");
            exit(1);
        }
    }
    while (!ctx.quit)
    {
        expire_timer();
        usleep(2500);
    }
    clear_timer();
    for (i = 0; i < ctx.thread; i++)
    {
        pthread_join(pid[i], NULL);
    }
    printf("all thread is closed\n");
    return 0;
}