apr_optional_hooks.h revision 251886 
1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16/**
17 * @file apr_optional_hooks.h
18 * @brief Apache optional hook functions
19 */
20
21
22#ifndef APR_OPTIONAL_HOOK_H
23#define APR_OPTIONAL_HOOK_H
24
25#include "apr_tables.h"
26
27#ifdef __cplusplus
28extern "C" {
29#endif
30/**
31 * @defgroup APR_Util_OPT_HOOK Optional Hook Functions
32 * @ingroup APR_Util_Hook
33 * @{
34 */
35/**
36 * Function to implemnt the APR_OPTIONAL_HOOK Macro
37 * @internal
38 * @see APR_OPTIONAL_HOOK
39 *
40 * @param name The name of the hook
41 * @param pfn A pointer to a function that will be called
42 * @param aszPre a NULL-terminated array of strings that name modules whose hooks should precede this one
43 * @param aszSucc a NULL-terminated array of strings that name modules whose hooks should succeed this one
44 * @param nOrder an integer determining order before honouring aszPre and aszSucc (for example HOOK_MIDDLE)
45 */
46
47
48APU_DECLARE(void) apr_optional_hook_add(const char *szName,void (*pfn)(void),
49					const char * const *aszPre,
50					const char * const *aszSucc,
51					int nOrder);
52
53/**
54 * Hook to an optional hook.
55 *
56 * @param ns The namespace prefix of the hook functions
57 * @param name The name of the hook
58 * @param pfn A pointer to a function that will be called
59 * @param aszPre a NULL-terminated array of strings that name modules whose hooks should precede this one
60 * @param aszSucc a NULL-terminated array of strings that name modules whose hooks should succeed this one
61 * @param nOrder an integer determining order before honouring aszPre and aszSucc (for example HOOK_MIDDLE)
62 */
63
64#define APR_OPTIONAL_HOOK(ns,name,pfn,aszPre,aszSucc,nOrder) do { \
65  ns##_HOOK_##name##_t *apu__hook = pfn; \
66  apr_optional_hook_add(#name,(void (*)(void))apu__hook,aszPre, aszSucc, nOrder); \
67} while (0)
68
69/**
70 * @internal
71 * @param szName - the name of the function
72 * @return the hook structure for a given hook
73 */
74APU_DECLARE(apr_array_header_t *) apr_optional_hook_get(const char *szName);
75
76/**
77 * Implement an optional hook that runs until one of the functions
78 * returns something other than OK or DECLINE.
79 *
80 * @param ns The namespace prefix of the hook functions
81 * @param link The linkage declaration prefix of the hook
82 * @param ret The type of the return value of the hook
83 * @param ret The type of the return value of the hook
84 * @param name The name of the hook
85 * @param args_decl The declaration of the arguments for the hook
86 * @param args_use The names for the arguments for the hook
87 * @param ok Success value
88 * @param decline Decline value
89 */
90#define APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(ns,link,ret,name,args_decl,args_use,ok,decline) \
91link##_DECLARE(ret) ns##_run_##name args_decl \
92    { \
93    ns##_LINK_##name##_t *pHook; \
94    int n; \
95    ret rv; \
96    apr_array_header_t *pHookArray=apr_optional_hook_get(#name); \
97\
98    if(!pHookArray) \
99	return ok; \
100\
101    pHook=(ns##_LINK_##name##_t *)pHookArray->elts; \
102    for(n=0 ; n < pHookArray->nelts ; ++n) \
103	{ \
104	rv=(pHook[n].pFunc)args_use; \
105\
106	if(rv != ok && rv != decline) \
107	    return rv; \
108	} \
109    return ok; \
110    }
111
112/** @} */
113#ifdef __cplusplus
114}
115#endif
116
117#endif /* APR_OPTIONAL_HOOK_H */
118