text: /* Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /**
   * @file apr_optional_hooks.h
   * @brief Apache optional hook functions
   */
  
  
  #ifndef APR_OPTIONAL_HOOK_H
  #define APR_OPTIONAL_HOOK_H
  
  #include "apr_tables.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  /** 
   * @defgroup APR_Util_OPT_HOOK Optional Hook Functions
   * @ingroup APR_Util_Hook
   * @{
   */
  /**
   * Function to implement the APR_OPTIONAL_HOOK Macro
   * @internal
   * @see APR_OPTIONAL_HOOK
   *
   * @param szName The name of the hook
   * @param pfn A pointer to a function that will be called
   * @param aszPre a NULL-terminated array of strings that name modules whose hooks should precede this one
   * @param aszSucc a NULL-terminated array of strings that name modules whose hooks should succeed this one
   * @param nOrder an integer determining order before honouring aszPre and aszSucc (for example HOOK_MIDDLE)
   */
  
  
  APU_DECLARE(void) apr_optional_hook_add(const char *szName,void (*pfn)(void),
  					const char * const *aszPre,
  					const char * const *aszSucc,
  					int nOrder);
  
  /**
   * Hook to an optional hook.
   *
   * @param ns The namespace prefix of the hook functions
   * @param name The name of the hook
   * @param pfn A pointer to a function that will be called
   * @param aszPre a NULL-terminated array of strings that name modules whose hooks should precede this one
   * @param aszSucc a NULL-terminated array of strings that name modules whose hooks should succeed this one
   * @param nOrder an integer determining order before honouring aszPre and aszSucc (for example HOOK_MIDDLE)
   */
  
  #define APR_OPTIONAL_HOOK(ns,name,pfn,aszPre,aszSucc,nOrder) do { \
    ns##_HOOK_##name##_t *apu__hook = pfn; \
    apr_optional_hook_add(#name,(void (*)(void))apu__hook,aszPre, aszSucc, nOrder); \
  } while (0)
  
  /**
   * @internal
   * @param szName - the name of the function
   * @return the hook structure for a given hook
   */
  APU_DECLARE(apr_array_header_t *) apr_optional_hook_get(const char *szName);
  
  /**
   * Implement an optional hook that runs until one of the functions
   * returns something other than OK or DECLINE.
   *
   * @param ns The namespace prefix of the hook functions
   * @param link The linkage declaration prefix of the hook
   * @param ret The type of the return value of the hook
   * @param ret The type of the return value of the hook
   * @param name The name of the hook
   * @param args_decl The declaration of the arguments for the hook
   * @param args_use The names for the arguments for the hook
   * @param ok Success value
   * @param decline Decline value
   */
  #define APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(ns,link,ret,name,args_decl,args_use,ok,decline) \
  link##_DECLARE(ret) ns##_run_##name args_decl \
      { \
      ns##_LINK_##name##_t *pHook; \
      int n; \
      ret rv; \
      apr_array_header_t *pHookArray=apr_optional_hook_get(#name); \
  \
      if(!pHookArray) \
  	return ok; \
  \
      pHook=(ns##_LINK_##name##_t *)pHookArray->elts; \
      for(n=0 ; n < pHookArray->nelts ; ++n) \
  	{ \
  	rv=(pHook[n].pFunc)args_use; \
  \
  	if(rv != ok && rv != decline) \
  	    return rv; \
  	} \
      return ok; \
      }
  
  /** @} */
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* APR_OPTIONAL_HOOK_H */
  