Hook Functions

Modules
	Hook probe capability
	Optional Hook Functions
Defines
#define	APR_IMPLEMENT_HOOK_GET_PROTO(ns, link, name) link##_DECLARE(apr_array_header_t *) ns##_hook_get_##name(void)
#define	APR_DECLARE_EXTERNAL_HOOK(ns, link, ret, name, args)
#define	APR_HOOK_STRUCT(members) static struct { members } _hooks;
#define	APR_HOOK_LINK(name) apr_array_header_t *link_##name;
#define	APR_IMPLEMENT_EXTERNAL_HOOK_BASE(ns, link, name)
#define	APR_IMPLEMENT_EXTERNAL_HOOK_VOID(ns, link, name, args_decl, args_use)
#define	APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL(ns, link, ret, name, args_decl, args_use, ok, decline)
#define	APR_IMPLEMENT_EXTERNAL_HOOK_RUN_FIRST(ns, link, ret, name, args_decl, args_use, decline)
#define	APR_HOOK_REALLY_FIRST (-10)
#define	APR_HOOK_FIRST 0
#define	APR_HOOK_MIDDLE 10
#define	APR_HOOK_LAST 20
#define	APR_HOOK_REALLY_LAST 30
Functions
void	apr_hook_sort_register (const char szHookName, apr_array_header_t *aHooks)
void	apr_hook_sort_all (void)
void	apr_hook_debug_show (const char szName, const char const aszPre, const char const *aszSucc)
void	apr_hook_deregister_all (void)
Variables
apr_pool_t *	apr_hook_global_pool
int	apr_hook_debug_enabled
const char *	apr_hook_debug_current

Define Documentation

#define APR_DECLARE_EXTERNAL_HOOK	(	ns,
		link,
		ret,
		name,
		args	)

Value:

typedef ret ns##_HOOK_##name##_t args; \
link##_DECLARE(void) ns##_hook_##name(ns##_HOOK_##name##_t *pf, \
                                      const char * const *aszPre, \
                                      const char * const *aszSucc, int nOrder); \
link##_DECLARE(ret) ns##_run_##name args; \
APR_IMPLEMENT_HOOK_GET_PROTO(ns,link,name); \
typedef struct ns##_LINK_##name##_t \
    { \
    ns##_HOOK_##name##_t *pFunc; \
    const char *szName; \
    const char * const *aszPredecessors; \
    const char * const *aszSuccessors; \
    int nOrder; \
    } ns##_LINK_##name##_t;

macro to declare the hook correctly

#define APR_HOOK_FIRST 0

run this hook first

#define APR_HOOK_LAST 20

run this hook after every other hook which is defined

#define APR_HOOK_LINK ( name ) apr_array_header_t *link_##name;

macro to link the hook structure

#define APR_HOOK_MIDDLE 10

run this hook somewhere

#define APR_HOOK_REALLY_FIRST (-10)

run this hook first, before ANYTHING

#define APR_HOOK_REALLY_LAST 30

run this hook last, after EVERYTHING

#define APR_HOOK_STRUCT ( members ) static struct { members } _hooks;

macro to declare the hook structure

#define APR_IMPLEMENT_EXTERNAL_HOOK_BASE	(	ns,
		link,
		name	)

Value:

link##_DECLARE(void) ns##_hook_##name(ns##_HOOK_##name##_t *pf,const char * const *aszPre, \
                                      const char * const *aszSucc,int nOrder) \
    { \
    ns##_LINK_##name##_t *pHook; \
    if(!_hooks.link_##name) \
        { \
        _hooks.link_##name=apr_array_make(apr_hook_global_pool,1,sizeof(ns##_LINK_##name##_t)); \
        apr_hook_sort_register(#name,&_hooks.link_##name); \
        } \
    pHook=apr_array_push(_hooks.link_##name); \
    pHook->pFunc=pf; \
    pHook->aszPredecessors=aszPre; \
    pHook->aszSuccessors=aszSucc; \
    pHook->nOrder=nOrder; \
    pHook->szName=apr_hook_debug_current; \
    if(apr_hook_debug_enabled) \
        apr_hook_debug_show(#name,aszPre,aszSucc); \
    } \
    APR_IMPLEMENT_HOOK_GET_PROTO(ns,link,name) \
    { \
        return _hooks.link_##name; \
    }

macro to implement the hook

#define APR_IMPLEMENT_EXTERNAL_HOOK_RUN_ALL	(	ns,
		link,
		ret,
		name,
		args_decl,
		args_use,
		ok,
		decline	)

Value:

APR_IMPLEMENT_EXTERNAL_HOOK_BASE(ns,link,name) \
link##_DECLARE(ret) ns##_run_##name args_decl \
    { \
    ns##_LINK_##name##_t *pHook; \
    int n; \
    ret rv = ok; \
    APR_HOOK_INT_DCL_UD; \
\
    APR_HOOK_PROBE_ENTRY(ud, ns, name, args_use); \
\
    if(_hooks.link_##name) \
        { \
        pHook=(ns##_LINK_##name##_t *)_hooks.link_##name->elts; \
        for(n=0 ; n < _hooks.link_##name->nelts ; ++n) \
            { \
            APR_HOOK_PROBE_INVOKE(ud, ns, name, (char *)pHook[n].szName, args_use); \
            rv=pHook[n].pFunc args_use; \
            APR_HOOK_PROBE_COMPLETE(ud, ns, name, (char *)pHook[n].szName, rv, args_use); \
            if(rv != ok && rv != decline) \
                break; \
            rv = ok; \
            } \
        } \
\
    APR_HOOK_PROBE_RETURN(ud, ns, name, rv, args_use); \
\
    return rv; \
    }

Implement a hook that runs until one of the functions returns something other than OK or DECLINE

Parameters:

	ns	The namespace prefix of the hook functions
	link	The linkage declaration prefix of the hook
	ret	Type to return
	name	The name of the hook
	args_decl	The declaration of the arguments for the hook
	args_use	The names for the arguments for the hook
	ok	Success value
	decline	Decline value

Note:: The link prefix FOO corresponds to FOO_DECLARE() macros, which provide export linkage from the module that IMPLEMENTs the hook, and import linkage from external modules that link to the hook's module.

#define APR_IMPLEMENT_EXTERNAL_HOOK_RUN_FIRST	(	ns,
		link,
		ret,
		name,
		args_decl,
		args_use,
		decline	)

Value:

APR_IMPLEMENT_EXTERNAL_HOOK_BASE(ns,link,name) \
link##_DECLARE(ret) ns##_run_##name args_decl \
    { \
    ns##_LINK_##name##_t *pHook; \
    int n; \
    ret rv = decline; \
    APR_HOOK_INT_DCL_UD; \
\
    APR_HOOK_PROBE_ENTRY(ud, ns, name, args_use); \
\
    if(_hooks.link_##name) \
        { \
        pHook=(ns##_LINK_##name##_t *)_hooks.link_##name->elts; \
        for(n=0 ; n < _hooks.link_##name->nelts ; ++n) \
            { \
            APR_HOOK_PROBE_INVOKE(ud, ns, name, (char *)pHook[n].szName, args_use); \
            rv=pHook[n].pFunc args_use; \
            APR_HOOK_PROBE_COMPLETE(ud, ns, name, (char *)pHook[n].szName, rv, args_use); \
\
            if(rv != decline) \
                break; \
            } \
        } \
\
    APR_HOOK_PROBE_RETURN(ud, ns, name, rv, args_use); \
\
    return rv; \
    }

Implement a hook that runs until the first function returns something other than the value of decline

Parameters:

	ns	The namespace prefix of the hook functions
	link	The linkage declaration prefix of the hook
	name	The name of the hook
	ret	Type to return
	args_decl	The declaration of the arguments for the hook
	args_use	The names for the arguments for the hook
	decline	Decline value

Note:: The link prefix FOO corresponds to FOO_DECLARE() macros, which provide export linkage from the module that IMPLEMENTs the hook, and import linkage from external modules that link to the hook's module.

#define APR_IMPLEMENT_EXTERNAL_HOOK_VOID	(	ns,
		link,
		name,
		args_decl,
		args_use	)

Value:

APR_IMPLEMENT_EXTERNAL_HOOK_BASE(ns,link,name) \
link##_DECLARE(void) ns##_run_##name args_decl \
    { \
    ns##_LINK_##name##_t *pHook; \
    int n; \
    APR_HOOK_INT_DCL_UD; \
\
    APR_HOOK_PROBE_ENTRY(ud, ns, name, args_use); \
\
    if(_hooks.link_##name) \
        { \
        pHook=(ns##_LINK_##name##_t *)_hooks.link_##name->elts; \
        for(n=0 ; n < _hooks.link_##name->nelts ; ++n) \
            { \
            APR_HOOK_PROBE_INVOKE(ud, ns, name, (char *)pHook[n].szName, args_use); \
            pHook[n].pFunc args_use; \
            APR_HOOK_PROBE_COMPLETE(ud, ns, name, (char *)pHook[n].szName, 0, args_use); \
            } \
        } \
\
    APR_HOOK_PROBE_RETURN(ud, ns, name, 0, args_use); \
\
    }

Implement a hook that has no return code, and therefore runs all of the registered functions

Parameters:

	ns	The namespace prefix of the hook functions
	link	The linkage declaration prefix of the hook
	name	The name of the hook
	args_decl	The declaration of the arguments for the hook
	args_use	The names for the arguments for the hook

Note:: The link prefix FOO corresponds to FOO_DECLARE() macros, which provide export linkage from the module that IMPLEMENTs the hook, and import linkage from external modules that link to the hook's module.

#define APR_IMPLEMENT_HOOK_GET_PROTO	(	ns,
		link,
		name	)	link##_DECLARE(apr_array_header_t *) ns##_hook_get_##name(void)

macro to return the prototype of the hook function

Function Documentation

void apr_hook_debug_show	(	const char *	szName,
		const char const	aszPre,
		const char const	aszSucc
	)

Print all of the information about the current hook. This is used for debugging purposes.

Parameters:

	szName	The name of the hook
	aszPre	All of the functions in the predecessor array
	aszSucc	All of the functions in the successor array

void apr_hook_deregister_all ( void )

Remove all currently registered functions.

void apr_hook_sort_all ( void )

Sort all of the registered functions for a given hook.

void apr_hook_sort_register	(	const char *	szHookName,
		apr_array_header_t **	aHooks
	)

Register a hook function to be sorted.

Parameters:

	szHookName	The name of the Hook the function is registered for
	aHooks	The array which stores all of the functions for this hook

Variable Documentation

const char* apr_hook_debug_current

The name of the module that is currently registering a function.

int apr_hook_debug_enabled

A global variable to determine if debugging information about the hooks functions should be printed.

apr_pool_t* apr_hook_global_pool

The global pool used to allocate any memory needed by the hooks.

Hook Functions

Modules

Defines

Functions

Variables

Define Documentation

Function Documentation

Variable Documentation