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/* runtime/weak dynamic JACK linking
*
* (C) 2014 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "weak_libjack.h"
#ifndef USE_WEAK_JACK
int have_libjack (void) {
return 0;
}
#else
#include <stdio.h>
#include <string.h>
#include <assert.h>
#ifdef PLATFORM_WINDOWS
#include <windows.h>
#else
#include <dlfcn.h>
#endif
static void* lib_open(const char* const so) {
#ifdef PLATFORM_WINDOWS
return (void*) LoadLibraryA(so);
#else
return dlopen(so, RTLD_NOW|RTLD_LOCAL);
#endif
}
static void* lib_symbol(void* const lib, const char* const sym) {
#ifdef PLATFORM_WINDOWS
return (void*) GetProcAddress((HMODULE)lib, sym);
#else
return dlsym(lib, sym);
#endif
}
#ifdef COMPILER_MSVC
typedef void * pvoid_t;
#define MAPSYM(SYM, FAIL) _j._ ## SYM = (func_t)lib_symbol(lib, "jack_" # SYM); \
if (!_j._ ## SYM) err |= FAIL;
#elif defined NDEBUG
typedef void * __attribute__ ((__may_alias__)) pvoid_t;
#define MAPSYM(SYM, FAIL) *(pvoid_t *)(&_j._ ## SYM) = lib_symbol(lib, "jack_" # SYM); \
if (!_j._ ## SYM) err |= FAIL;
#else
typedef void * __attribute__ ((__may_alias__)) pvoid_t;
#define MAPSYM(SYM, FAIL) *(pvoid_t *)(&_j._ ## SYM) = lib_symbol(lib, "jack_" # SYM); \
if (!_j._ ## SYM) { \
if (FAIL) { \
fprintf(stderr, "*** WEAK-JACK: required symbol 'jack_%s' was not found\n", "" # SYM); \
} \
err |= FAIL; \
}
#endif
typedef void (* func_t) (void);
/* function pointers to the real jack API */
static struct WeakJack {
func_t _client_open; // special case due to varargs
#define JCFUN(ERR, RTYPE, NAME, RVAL) func_t _ ## NAME ;
#define JPFUN(ERR, RTYPE, NAME, DEF, ARGS, RVAL) func_t _ ## NAME ;
#define JXFUN(ERR, RTYPE, NAME, DEF, ARGS, CODE) func_t _ ## NAME ;
#define JVFUN(ERR, NAME, DEF, ARGS, CODE) func_t _ ## NAME ;
#include "weak_libjack.def"
#undef JCFUN
#undef JPFUN
#undef JXFUN
#undef JVFUN
} _j;
static int _status = -1;
__attribute__((constructor))
static void init_weak_jack(void)
{
void* lib;
int err = 0;
#ifndef NDEBUG
fprintf(stderr, "*** WEAK-JACK: initializing\n");
#endif
memset(&_j, 0, sizeof(_j));
#ifdef __APPLE__
lib = lib_open("libjack.dylib");
if (!lib) {
lib = lib_open("/usr/local/lib/libjack.dylib");
}
#elif (defined PLATFORM_WINDOWS)
# if ( defined(__x86_64__) || defined(_M_X64) )
lib = lib_open("libjack64.dll");
# else
lib = lib_open("libjack.dll");
# endif
#else
lib = lib_open("libjack.so.0");
#endif
if (!lib) {
#ifndef NDEBUG
fprintf(stderr, "*** WEAK-JACK: libjack was not found\n");
#endif
_status = -2;
return;
}
/* found library, now lookup functions */
MAPSYM(client_open, 2)
#define JCFUN(ERR, RTYPE, NAME, RVAL) MAPSYM(NAME, ERR)
#define JPFUN(ERR, RTYPE, NAME, DEF, ARGS, RVAL) MAPSYM(NAME, ERR)
#define JXFUN(ERR, RTYPE, NAME, DEF, ARGS, CODE) MAPSYM(NAME, ERR)
#define JVFUN(ERR, NAME, DEF, ARGS, CODE) MAPSYM(NAME, ERR)
#include "weak_libjack.def"
#undef JCFUN
#undef JPFUN
#undef JXFUN
#undef JVFUN
/* if a required symbol is not found, disable JACK completly */
if (err) {
_j._client_open = NULL;
}
_status = err;
#ifndef NDEBUG
fprintf(stderr, "*** WEAK-JACK: %s. (%d)\n", err ? "jack is not available" : "OK", _status);
#endif
}
int have_libjack (void) {
if (_status == -1) {
init_weak_jack();
}
return _status;
}
/*******************************************************************************
* helper macros
*/
#if defined(__GNUC__) && (__GNUC__ > 2) && !defined(NDEBUG)
#define likely(expr) (__builtin_expect (!!(expr), 1))
#else
#define likely(expr) (expr)
#endif
#ifndef NDEBUG
# define WJACK_WARNING(NAME) \
fprintf(stderr, "*** WEAK-JACK: function 'jack_%s' ignored\n", "" # NAME);
#else
# define WJACK_WARNING(NAME) ;
#endif
/******************************************************************************
* JACK API wrapper functions.
*
* if a function pointer is set in the static struct WeakJack _j,
* the function is called directly.
* Otherwise a dummy NOOP implementation is provided.
* The latter is mainly for compile-time warnings.
*
* If libjack is not found, jack_client_open() will fail.
* In that case the application should not call any other libjack
* functions. Hence a real implementation is not needed.
* (jack ringbuffer may be an exception for some apps)
*/
/* dedicated support for jack_client_open(,..) variable arg function macro */
func_t WJACK_get_client_open(void) {
if (_status == -1) {
init_weak_jack();
}
return _j._client_open;
}
/* callback to set status */
jack_client_t * WJACK_no_client_open (const char *client_name, jack_options_t options, jack_status_t *status, ...) {
WJACK_WARNING(client_open);
if (status) { *status = JackFailure; }
return NULL;
}
/*******************************************************************************
* Macros to wrap jack API
*/
/* abstraction for jack_client functions
* rtype jack_function_name (jack_client_t *client) { return rval; }
*/
#define JCFUN(ERR, RTYPE, NAME, RVAL) \
RTYPE WJACK_ ## NAME (jack_client_t *client) { \
if likely(_j._ ## NAME) { \
return ((RTYPE (*)(jack_client_t *client)) _j._ ## NAME)(client); \
} else { \
WJACK_WARNING(NAME) \
return RVAL; \
} \
}
/* abstraction for NOOP functions with return value
* rtype jack_function_name (ARGS) { return rval; }
*/
#define JPFUN(ERR, RTYPE, NAME, DEF, ARGS, RVAL) \
RTYPE WJACK_ ## NAME DEF { \
if likely(_j._ ## NAME) { \
return ((RTYPE (*)DEF) _j._ ## NAME) ARGS; \
} else { \
WJACK_WARNING(NAME) \
return RVAL; \
} \
}
/* abstraction for functions that need custom code.
* e.g. functions with return-value-pointer args,
* use CODE to initialize value
*
* rtype jack_function_name (ARGS) { CODE }
*/
#define JXFUN(ERR, RTYPE, NAME, DEF, ARGS, CODE) \
RTYPE WJACK_ ## NAME DEF { \
if likely(_j._ ## NAME) { \
return ((RTYPE (*)DEF) _j._ ## NAME) ARGS; \
} else { \
WJACK_WARNING(NAME) \
CODE \
} \
}
/* abstraction for void functions with return-value-pointer args
* void jack_function_name (ARGS) { CODE }
*/
#define JVFUN(ERR, NAME, DEF, ARGS, CODE) \
void WJACK_ ## NAME DEF { \
if likely(_j._ ## NAME) { \
((void (*)DEF) _j._ ## NAME) ARGS; \
} else { \
WJACK_WARNING(NAME) \
CODE \
} \
}
#include "weak_libjack.def"
#undef JCFUN
#undef JPFUN
#undef JXFUN
#undef JVFUN
#endif // end USE_WEAK_JACK
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