Apache Portable Runtime Utility Library
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Modules | Macros | Functions | Variables
Hook Functions
APR Utility Functions

Modules

 Hook probe capability
 Optional Hook Functions

Macros

#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

Detailed Description


Macro Definition 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:
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:
nsThe namespace prefix of the hook functions
linkThe linkage declaration prefix of the hook
retType to return
nameThe name of the hook
args_declThe declaration of the arguments for the hook
args_useThe names for the arguments for the hook
okSuccess value
declineDecline 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:
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:
nsThe namespace prefix of the hook functions
linkThe linkage declaration prefix of the hook
nameThe name of the hook
retType to return
args_declThe declaration of the arguments for the hook
args_useThe names for the arguments for the hook
declineDecline 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:
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:
nsThe namespace prefix of the hook functions
linkThe linkage declaration prefix of the hook
nameThe name of the hook
args_declThe declaration of the arguments for the hook
args_useThe 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:
szNameThe name of the hook
aszPreAll of the functions in the predecessor array
aszSuccAll 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 registerd 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:
szHookNameThe name of the Hook the function is registered for
aHooksThe 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.