curl_memory.h: introduce CURLX_NO_MEMORY_CALLBACKS usage possibility

This commit alone does not fix anything nor modifies existing
interfaces or behaviors, although it is a prerequisite for other
fixes.
This commit is contained in:
Yang Tse 2013-02-07 20:12:04 +01:00
parent 01dc954f8a
commit 001e664ff7
2 changed files with 86 additions and 4 deletions

View File

@ -7,7 +7,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2009, Daniel Stenberg, <daniel@haxx.se>, et al.
* Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
@ -22,7 +22,65 @@
*
***************************************************************************/
#include <curl/curl.h> /* for the typedefs */
/*
* Nasty internal details ahead...
*
* File curl_memory.h must be included by _all_ *.c source files
* that use memory related functions strdup, malloc, calloc, realloc
* or free, and given source file is used to build libcurl library.
*
* There is nearly no exception to above rule. All libcurl source
* files in 'lib' subdirectory as well as those living deep inside
* 'packages' subdirectories and linked together in order to build
* libcurl library shall follow it.
*
* File lib/strdup.c is an exception, given that it provides a strdup
* clone implementation while using malloc. Extra care needed inside
* this one. TODO: revisit this paragraph and related code.
*
* The need for curl_memory.h inclusion is due to libcurl's feature
* of allowing library user to provide memory replacement functions,
* memory callbacks, at runtime with curl_global_init_mem()
*
* Any *.c source file used to build libcurl library that does not
* include curl_memory.h and uses any memory function of the five
* mentioned above will compile without any indication, but it will
* trigger weird memory related issues at runtime.
*
* OTOH some source files from 'lib' subdirectory may additionally be
* used directly as source code when using some curlx_ functions by
* third party programs that don't even use libcurl at all. When using
* these source files in this way it is necessary these are compiled
* with CURLX_NO_MEMORY_CALLBACKS defined, in order to ensure that no
* attempt of calling libcurl's memory callbacks is done from code
* which can not use this machinery.
*
* Notice that libcurl's 'memory tracking' system works chaining into
* the memory callback machinery. This implies that when compiling
* 'lib' source files with CURLX_NO_MEMORY_CALLBACKS defined this file
* disengages usage of libcurl's 'memory tracking' system, defining
* MEMDEBUG_NODEFINES and overriding CURLDEBUG purpose.
*
* CURLX_NO_MEMORY_CALLBACKS takes precedence over CURLDEBUG. This is
* done in order to allow building a 'memory tracking' enabled libcurl
* and at the same time allow building programs which do not use it.
*
* Programs and libraries in 'tests' subdirectories have specific
* purposes and needs, and as such each one will use whatever fits
* best, depending additionally wether it links with libcurl or not.
*
* Caveat emptor. Proper curlx_* separation is a work in progress
* the same as CURLX_NO_MEMORY_CALLBACKS usage, some adjustments may
* still be required. IOW don't use them yet, there are sharp edges.
*/
#ifdef HEADER_CURL_MEMDEBUG_H
#error "Header memdebug.h shall not be included before curl_memory.h"
#endif
#ifndef CURLX_NO_MEMORY_CALLBACKS
#include <curl/curl.h> /* for the callback typedefs */
extern curl_malloc_callback Curl_cmalloc;
extern curl_free_callback Curl_cfree;
@ -31,8 +89,16 @@ extern curl_strdup_callback Curl_cstrdup;
extern curl_calloc_callback Curl_ccalloc;
#ifndef CURLDEBUG
/* Only do this define-mania if we're not using the memdebug system, as that
has preference on this magic. */
/*
* libcurl's 'memory tracking' system defines strdup, malloc, calloc,
* realloc and free, along with others, in memdebug.h in a different
* way although still using memory callbacks forward declared above.
* When using the 'memory tracking' system (CURLDEBUG defined) we do
* not define here the five memory functions given that definitions
* from memdebug.h are the ones that shall be used.
*/
#undef strdup
#define strdup(ptr) Curl_cstrdup(ptr)
#undef malloc
@ -44,6 +110,14 @@ extern curl_calloc_callback Curl_ccalloc;
#undef free
#define free(ptr) Curl_cfree(ptr)
#endif /* CURLDEBUG */
#else /* CURLX_NO_MEMORY_CALLBACKS */
#ifndef MEMDEBUG_NODEFINES
#define MEMDEBUG_NODEFINES
#endif
#endif /* CURLX_NO_MEMORY_CALLBACKS */
#endif /* HEADER_CURL_MEMORY_H */

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@ -22,6 +22,14 @@
#include "curl_setup.h"
/*
* See comment in curl_memory.h for the explanation of this sanity check.
*/
#ifdef CURLX_NO_MEMORY_CALLBACKS
#error "libcurl shall not ever be built with CURLX_NO_MEMORY_CALLBACKS defined"
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif