Fri Aug 24 02:28:31 2007

Asterisk developer's documentation


threadstorage.h File Reference

Definitions to aid in the use of thread local storage. More...

#include <pthread.h>
#include "asterisk/utils.h"
#include "asterisk/inline_api.h"

Include dependency graph for threadstorage.h:

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Go to the source code of this file.

Data Structures

struct  ast_threadstorage
 data for a thread locally stored variable More...

Defines

#define ast_dynamic_str_thread_append_va(buf, max_len, ts, fmt, ap)
 Append to a thread local dynamic string using a va_list.
#define ast_dynamic_str_thread_set_va(buf, max_len, ts, fmt, ap)
 Set a thread locally stored dynamic string from a va_list.
#define AST_THREADSTORAGE(name, name_init)   AST_THREADSTORAGE_CUSTOM(name, name_init, ast_free)
 Define a thread storage variable.
#define AST_THREADSTORAGE_CUSTOM(name, name_init, cleanup)
#define THREADSTORAGE_ONCE_INIT   PTHREAD_ONCE_INIT

Functions

 ast_dynamic_str_thread_append (struct ast_dynamic_str **buf, size_t max_len, struct ast_threadstorage *ts, const char *fmt,...)
int ast_dynamic_str_thread_build_va (struct ast_dynamic_str **buf, size_t max_len, struct ast_threadstorage *ts, int append, const char *fmt, va_list ap)
 Core functionality of ast_dynamic_str_thread_(set|append)_va.
 AST_INLINE_API (int __attribute__((format(printf, 4, 5))) ast_dynamic_str_thread_set(struct ast_dynamic_str **buf, size_t max_len, struct ast_threadstorage *ts, const char *fmt,...),{int res;va_list ap;va_start(ap, fmt);res=ast_dynamic_str_thread_set_va(buf, max_len, ts, fmt, ap);va_end(ap);return res;}) AST_INLINE_API(int __attribute__((format(printf
 Set a thread locally stored dynamic string using variable argumentsAppend to a thread local dynamic string.
 AST_INLINE_API (struct ast_dynamic_str *attribute_malloc ast_dynamic_str_create(size_t init_len),{struct ast_dynamic_str *buf;if(!(buf=ast_calloc(1, sizeof(*buf)+init_len))) return NULL;buf->len=init_len;return buf;}) AST_INLINE_API(struct ast_dynamic_str *ast_dynamic_str_thread_get(struct ast_threadstorage *ts
 Create a dynamic length stringRetrieve a thread locally stored dynamic string.
 AST_INLINE_API (void *ast_threadstorage_get(struct ast_threadstorage *ts, size_t init_size),{void *buf;pthread_once(&ts->once, ts->key_init);if(!(buf=pthread_getspecific(ts->key))){if(!(buf=ast_calloc(1, init_size))) return NULL;pthread_setspecific(ts->key, buf);}return buf;}) struct ast_dynamic_str
 Retrieve thread storageA dynamic length string.

Variables

size_t init_len


Detailed Description

Definitions to aid in the use of thread local storage.

Author:
Russell Bryant <russell@digium.com>

Definition in file threadstorage.h.


Define Documentation

#define ast_dynamic_str_thread_append_va ( buf,
max_len,
ts,
fmt,
ap   ) 

Append to a thread local dynamic string using a va_list.

The arguments, return values, and usage of this are the same as those for ast_dynamic_str_thread_set_va(). However, instead of setting a new value for the string, this will append to the current value.

Definition at line 366 of file threadstorage.h.

Referenced by manager_event().

#define ast_dynamic_str_thread_set_va ( buf,
max_len,
ts,
fmt,
ap   ) 

Set a thread locally stored dynamic string from a va_list.

Returns:
The return value of this function is the same as that of the printf family of functions.
Example usage:
 AST_THREADSTORAGE(my_str, my_str_init);
 #define MY_STR_INIT_SIZE   128
 ...
 void my_func(const char *fmt, ...)
 {
      struct ast_dynamic_str *buf;
      va_list ap;

      if (!(buf = ast_dynamic_str_thread_get(&my_str, MY_STR_INIT_SIZE)))
           return;
      ...
      va_start(fmt, ap);
      ast_dynamic_str_thread_set_va(&buf, 0, &my_str, fmt, ap);
      va_end(ap);
 
      printf("This is the string we just built: %s\n", buf->str);
      ...
 }

Definition at line 348 of file threadstorage.h.

Referenced by ast_cli(), ast_log(), ast_verbose(), and astman_append().

#define AST_THREADSTORAGE ( name,
name_init   )     AST_THREADSTORAGE_CUSTOM(name, name_init, ast_free)

Define a thread storage variable.

This macro would be used to declare an instance of thread storage in a file.

Example usage:

 AST_THREADSTORAGE(my_buf, my_buf_init);

Definition at line 92 of file threadstorage.h.

#define AST_THREADSTORAGE_CUSTOM ( name,
name_init,
cleanup   ) 

Definition at line 96 of file threadstorage.h.

#define THREADSTORAGE_ONCE_INIT   PTHREAD_ONCE_INIT

Definition at line 68 of file threadstorage.h.


Function Documentation

ast_dynamic_str_thread_append ( struct ast_dynamic_str **  buf,
size_t  max_len,
struct ast_threadstorage ts,
const char *  fmt,
  ... 
)

Referenced by manager_event().

int ast_dynamic_str_thread_build_va ( struct ast_dynamic_str **  buf,
size_t  max_len,
struct ast_threadstorage ts,
int  append,
const char *  fmt,
va_list  ap 
)

Core functionality of ast_dynamic_str_thread_(set|append)_va.

The arguments to this function are the same as those described for ast_dynamic_str_thread_set_va except for an addition argument, append. If append is non-zero, this will append to the current string instead of writing over it.

In the case that this function is called and the buffer was not large enough to hold the result, the partial write will be truncated, and the result AST_DYNSTR_BUILD_RETRY will be returned to indicate that the buffer size was increased, and the function should be called a second time.

A return of AST_DYNSTR_BUILD_FAILED indicates a memory allocation error.

A return value greater than or equal to zero indicates the number of characters that have been written, not including the terminating ''. In the append case, this only includes the number of characters appended.

Note:
This function should never need to be called directly. It should through calling one of the other functions or macros defined in this file.

Definition at line 1221 of file utils.c.

References ast_realloc, ast_threadstorage::key, and offset.

01223 {
01224    int res;
01225    int offset = (append && (*buf)->len) ? strlen((*buf)->str) : 0;
01226 #if defined(DEBUG_THREADLOCALS)
01227    struct ast_dynamic_str *old_buf = *buf;
01228 #endif /* defined(DEBUG_THREADLOCALS) */
01229 
01230    res = vsnprintf((*buf)->str + offset, (*buf)->len - offset, fmt, ap);
01231 
01232    /* Check to see if there was not enough space in the string buffer to prepare
01233     * the string.  Also, if a maximum length is present, make sure the current
01234     * length is less than the maximum before increasing the size. */
01235    if ((res + offset + 1) > (*buf)->len && (max_len ? ((*buf)->len < max_len) : 1)) {
01236       /* Set the new size of the string buffer to be the size needed
01237        * to hold the resulting string (res) plus one byte for the
01238        * terminating '\0'.  If this size is greater than the max, set
01239        * the new length to be the maximum allowed. */
01240       if (max_len)
01241          (*buf)->len = ((res + offset + 1) < max_len) ? (res + offset + 1) : max_len;
01242       else
01243          (*buf)->len = res + offset + 1;
01244 
01245       if (!(*buf = ast_realloc(*buf, (*buf)->len + sizeof(*(*buf)))))
01246          return AST_DYNSTR_BUILD_FAILED;
01247 
01248       if (append)
01249          (*buf)->str[offset] = '\0';
01250 
01251       if (ts) {
01252          pthread_setspecific(ts->key, *buf);
01253 #if defined(DEBUG_THREADLOCALS)
01254          __ast_threadstorage_object_replace(old_buf, *buf, (*buf)->len + sizeof(*(*buf)));
01255 #endif /* defined(DEBUG_THREADLOCALS) */
01256       }
01257 
01258       /* va_end() and va_start() must be done before calling
01259        * vsnprintf() again. */
01260       return AST_DYNSTR_BUILD_RETRY;
01261    }
01262 
01263    return res;
01264 }

AST_INLINE_API ( int   __attribute__((format(printf, 4, 5))) ast_dynamic_str_thread_set(struct ast_dynamic_str **buf, size_t max_len,struct ast_threadstorage *ts, const char *fmt,...)  ) 

Set a thread locally stored dynamic string using variable argumentsAppend to a thread local dynamic string.

The arguments, return values, and usage of this function are the same as ast_dynamic_str_thread_set(). However, instead of setting a new value for the string, this function appends to the current value.

AST_INLINE_API ( struct ast_dynamic_str *attribute_malloc   ast_dynamic_str_create(size_t init_len)  ) 

Create a dynamic length stringRetrieve a thread locally stored dynamic string.

Returns:
This function will return the thread locally stored dynamic string associated with the thread storage management variable passed as the first argument. The result will be NULL in the case of a memory allocation error.
Example usage:
 AST_THREADSTORAGE(my_str, my_str_init);
 #define MY_STR_INIT_SIZE   128
 ...
 void my_func(const char *fmt, ...)
 {
      struct ast_dynamic_str *buf;

      if (!(buf = ast_dynamic_str_thread_get(&my_str, MY_STR_INIT_SIZE)))
           return;
      ...
 }

AST_INLINE_API ( void *  ast_threadstorage_get(struct ast_threadstorage *ts, size_t init_size)  ) 

Retrieve thread storageA dynamic length string.

Definition at line 155 of file threadstorage.h.

References ast_calloc.

00157 {
00158    void *buf;
00159 
00160    pthread_once(&ts->once, ts->key_init);
00161    if (!(buf = pthread_getspecific(ts->key))) {
00162       if (!(buf = ast_calloc(1, init_size)))
00163          return NULL;
00164       pthread_setspecific(ts->key, buf);
00165    }
00166 
00167    return buf;
00168 }
00169 )
00170 #else /* defined(DEBUG_THREADLOCALS) */
00171 AST_INLINE_API(
00172 void *__ast_threadstorage_get(struct ast_threadstorage *ts, size_t init_size, const char *file, const char *function, unsigned int line),
00173 {
00174    void *buf;
00175 
00176    pthread_once(&ts->once, ts->key_init);
00177    if (!(buf = pthread_getspecific(ts->key))) {
00178       if (!(buf = ast_calloc(1, init_size)))
00179          return NULL;
00180       pthread_setspecific(ts->key, buf);
00181       __ast_threadstorage_object_add(buf, init_size, file, function, line);
00182    }
00183 
00184    return buf;
00185 }
00186 )
00187 
00188 #define ast_threadstorage_get(ts, init_size) __ast_threadstorage_get(ts, init_size, __FILE__, __PRETTY_FUNCTION__, __LINE__)
00189 #endif /* defined(DEBUG_THREADLOCALS) */
00190 
00191 /*!
00192  * \brief A dynamic length string
00193  */
00194 struct ast_dynamic_str {
00195    /* The current maximum length of the string */
00196    size_t len;
00197    /* The string buffer */
00198    char str[0];
00199 };


Variable Documentation

size_t init_len

Definition at line 260 of file threadstorage.h.


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