Create an explicit EventLoop class which can be used to run an event loop

[thirdparty/squid.git] / src / event.h

/*
 * $Id: event.h,v 1.1 2006/08/07 02:28:22 robertc Exp $
 *
 *
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 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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#ifndef SQUID_EVENT_H
#define SQUID_EVENT_H

#include "squid.h"
#include "Array.h"
#include "CompletionDispatcher.h"

/* forward decls */

class StoreEntry;

/* event scheduling facilities - run a callback after a given time period. */

typedef void EVH(void *);

extern void eventAdd(const char *name, EVH * func, void *arg, double when, int, bool cbdata=true);
SQUIDCEXTERN void eventAddIsh(const char *name, EVH * func, void *arg, double delta_ish, int);
SQUIDCEXTERN void eventDelete(EVH * func, void *arg);
SQUIDCEXTERN void eventInit(CacheManager &);
SQUIDCEXTERN void eventFreeMemory(void);
SQUIDCEXTERN int eventFind(EVH *, void *);

class ev_entry
{

public:
    ev_entry(char const * name, EVH * func, void *arg, double when, int weight, bool cbdata=true);
    MEMPROXY_CLASS(ev_entry);
    const char *name;
    EVH *func;
    void *arg;
    double when;

    int weight;
    bool cbdata;

    struct ev_entry *next;
};

MEMPROXY_CLASS_INLINE(ev_entry);

class EventDispatcher : public CompletionDispatcher
{

public:
    EventDispatcher();
    /* add an event to dequeue when dispatch is called */

    void add
        (ev_entry *);

    /* add an event to be dispatched in the future */
    void add
        (const char *name, EVH * func, void *arg, double when, int, bool cbdata=true);

    void dispatch();

    static EventDispatcher *GetInstance();

private:
    Vector<ev_entry *> queue;

    static EventDispatcher _instance;
};

class EventScheduler
{

public:
    /* Create an event scheduler that will hand its ready to run callbacks to
     * an EventDispatcher */
    EventScheduler(EventDispatcher *);
    ~EventScheduler();
    /* cancel a scheduled but not dispatched event */
    void cancel(EVH * func, void * arg);
    /* clean up the used memory in the scheduler */
    void clean();
    /* how long until the next event ? */
    int checkDelay();
    /* cache manager output for the event queue */
    void dump(StoreEntry *);
    /* find a scheduled event */
    bool find(EVH * func, void * arg);
    /* schedule a callback function to run in when seconds */
    void schedule(const char *name, EVH * func, void *arg, double when, int weight, bool cbdata=true);
    int checkEvents();
    static EventScheduler *GetInstance();

private:
    static EventScheduler _instance;
    EventDispatcher * dispatcher;
    ev_entry * tasks;
};

#endif /* SQUID_EVENT_H */