mirror of
https://github.com/Ryujinx/SDL.git
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fa8c83c1c1
As Tiffany pointed out in Bugzilla, volatile is not useful for thread safety: https://software.intel.com/en-us/blogs/2007/11/30/volatile-almost-useless-for-multi-threaded-programming/ Some of these volatiles didn't need to be, some were otherwise protected by spinlocks or mutexes, and some got moved over to SDL_atomic_t data, etc. Fixes Bugzilla #3220.
320 lines
11 KiB
C
320 lines
11 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "SDL_config.h"
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#include "SDL_dynapi.h"
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#if SDL_DYNAMIC_API
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#include "SDL.h"
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/* !!! FIXME: Shouldn't these be included in SDL.h? */
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#include "SDL_shape.h"
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#include "SDL_syswm.h"
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/* This is the version of the dynamic API. This doesn't match the SDL version
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and should not change until there's been a major revamp in API/ABI.
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So 2.0.5 adds functions over 2.0.4? This number doesn't change;
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the sizeof (jump_table) changes instead. But 2.1.0 changes how a function
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works in an incompatible way or removes a function? This number changes,
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since sizeof (jump_table) isn't sufficient anymore. It's likely
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we'll forget to bump every time we add a function, so this is the
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failsafe switch for major API change decisions. Respect it and use it
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sparingly. */
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#define SDL_DYNAPI_VERSION 1
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static void SDL_InitDynamicAPI(void);
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/* BE CAREFUL CALLING ANY SDL CODE IN HERE, IT WILL BLOW UP.
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Even self-contained stuff might call SDL_Error and break everything. */
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/* behold, the macro salsa! */
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/* !!! FIXME: ...disabled...until we write it. :) */
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#define DISABLE_JUMP_MAGIC 1
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#if DISABLE_JUMP_MAGIC
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/* Can't use the macro for varargs nonsense. This is atrocious. */
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#define SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, logname, prio) \
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_static void SDL_Log##logname##name(int category, SDL_PRINTF_FORMAT_STRING const char *fmt, ...) { \
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va_list ap; initcall; va_start(ap, fmt); \
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jump_table.SDL_LogMessageV(category, SDL_LOG_PRIORITY_##prio, fmt, ap); \
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va_end(ap); \
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}
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#define SDL_DYNAPI_VARARGS(_static, name, initcall) \
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_static int SDL_SetError##name(SDL_PRINTF_FORMAT_STRING const char *fmt, ...) { \
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char buf[512]; /* !!! FIXME: dynamic allocation */ \
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va_list ap; initcall; va_start(ap, fmt); \
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jump_table.SDL_vsnprintf(buf, sizeof (buf), fmt, ap); \
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va_end(ap); \
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return jump_table.SDL_SetError("%s", buf); \
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} \
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_static int SDL_sscanf##name(const char *buf, SDL_SCANF_FORMAT_STRING const char *fmt, ...) { \
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int retval; va_list ap; initcall; va_start(ap, fmt); \
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retval = jump_table.SDL_vsscanf(buf, fmt, ap); \
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va_end(ap); \
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return retval; \
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} \
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_static int SDL_snprintf##name(SDL_OUT_Z_CAP(maxlen) char *buf, size_t maxlen, SDL_PRINTF_FORMAT_STRING const char *fmt, ...) { \
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int retval; va_list ap; initcall; va_start(ap, fmt); \
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retval = jump_table.SDL_vsnprintf(buf, maxlen, fmt, ap); \
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va_end(ap); \
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return retval; \
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} \
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_static void SDL_Log##name(SDL_PRINTF_FORMAT_STRING const char *fmt, ...) { \
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va_list ap; initcall; va_start(ap, fmt); \
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jump_table.SDL_LogMessageV(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO, fmt, ap); \
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va_end(ap); \
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} \
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_static void SDL_LogMessage##name(int category, SDL_LogPriority priority, SDL_PRINTF_FORMAT_STRING const char *fmt, ...) { \
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va_list ap; initcall; va_start(ap, fmt); \
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jump_table.SDL_LogMessageV(category, priority, fmt, ap); \
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va_end(ap); \
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} \
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SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, Verbose, VERBOSE) \
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SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, Debug, DEBUG) \
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SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, Info, INFO) \
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SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, Warn, WARN) \
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SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, Error, ERROR) \
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SDL_DYNAPI_VARARGS_LOGFN(_static, name, initcall, Critical, CRITICAL)
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#endif
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/* Typedefs for function pointers for jump table, and predeclare funcs */
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/* The DEFAULT funcs will init jump table and then call real function. */
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/* The REAL funcs are the actual functions, name-mangled to not clash. */
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) \
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typedef rc (*SDL_DYNAPIFN_##fn) params; \
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static rc fn##_DEFAULT params; \
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extern rc fn##_REAL params;
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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/* The jump table! */
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typedef struct {
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) SDL_DYNAPIFN_##fn fn;
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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} SDL_DYNAPI_jump_table;
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/* Predeclare the default functions for initializing the jump table. */
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) static rc fn##_DEFAULT params;
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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/* The actual jump table. */
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static SDL_DYNAPI_jump_table jump_table = {
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) fn##_DEFAULT,
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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};
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/* Default functions init the function table then call right thing. */
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#if DISABLE_JUMP_MAGIC
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) \
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static rc fn##_DEFAULT params { \
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SDL_InitDynamicAPI(); \
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ret jump_table.fn args; \
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}
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#define SDL_DYNAPI_PROC_NO_VARARGS 1
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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#undef SDL_DYNAPI_PROC_NO_VARARGS
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SDL_DYNAPI_VARARGS(static, _DEFAULT, SDL_InitDynamicAPI())
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#else
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/* !!! FIXME: need the jump magic. */
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#error Write me.
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#endif
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/* Public API functions to jump into the jump table. */
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#if DISABLE_JUMP_MAGIC
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) \
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rc fn params { ret jump_table.fn args; }
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#define SDL_DYNAPI_PROC_NO_VARARGS 1
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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#undef SDL_DYNAPI_PROC_NO_VARARGS
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SDL_DYNAPI_VARARGS(,,)
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#else
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/* !!! FIXME: need the jump magic. */
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#error Write me.
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#endif
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/* Here's the exported entry point that fills in the jump table. */
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/* Use specific types when an "int" might suffice to keep this sane. */
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typedef Sint32 (SDLCALL *SDL_DYNAPI_ENTRYFN)(Uint32 apiver, void *table, Uint32 tablesize);
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extern DECLSPEC Sint32 SDLCALL SDL_DYNAPI_entry(Uint32, void *, Uint32);
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Sint32
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SDL_DYNAPI_entry(Uint32 apiver, void *table, Uint32 tablesize)
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{
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SDL_DYNAPI_jump_table *output_jump_table = (SDL_DYNAPI_jump_table *) table;
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if (apiver != SDL_DYNAPI_VERSION) {
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/* !!! FIXME: can maybe handle older versions? */
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return -1; /* not compatible. */
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} else if (tablesize > sizeof (jump_table)) {
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return -1; /* newer version of SDL with functions we can't provide. */
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}
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/* Init our jump table first. */
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#define SDL_DYNAPI_PROC(rc,fn,params,args,ret) jump_table.fn = fn##_REAL;
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#include "SDL_dynapi_procs.h"
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#undef SDL_DYNAPI_PROC
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/* Then the external table... */
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if (output_jump_table != &jump_table) {
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jump_table.SDL_memcpy(output_jump_table, &jump_table, tablesize);
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}
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/* Safe to call SDL functions now; jump table is initialized! */
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return 0; /* success! */
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}
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/* Obviously we can't use SDL_LoadObject() to load SDL. :) */
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/* Also obviously, we never close the loaded library. */
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#if defined(WIN32) || defined(_WIN32) || defined(__CYGWIN__)
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#ifndef WIN32_LEAN_AND_MEAN
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#define WIN32_LEAN_AND_MEAN 1
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#endif
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#include <windows.h>
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static SDL_INLINE void *get_sdlapi_entry(const char *fname, const char *sym)
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{
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HANDLE lib = LoadLibraryA(fname);
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void *retval = NULL;
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if (lib) {
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retval = GetProcAddress(lib, sym);
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if (retval == NULL) {
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FreeLibrary(lib);
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}
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}
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return retval;
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}
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#elif defined(__HAIKU__)
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#include <os/kernel/image.h>
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static SDL_INLINE void *get_sdlapi_entry(const char *fname, const char *sym)
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{
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image_id lib = load_add_on(fname);
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void *retval = NULL;
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if (lib >= 0) {
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if (get_image_symbol(lib, sym, B_SYMBOL_TYPE_TEXT, &retval) != B_NO_ERROR) {
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unload_add_on(lib);
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retval = NULL;
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}
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}
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return retval;
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}
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#elif defined(unix) || defined(__unix__) || defined(__APPLE__)
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#include <dlfcn.h>
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static SDL_INLINE void *get_sdlapi_entry(const char *fname, const char *sym)
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{
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void *lib = dlopen(fname, RTLD_NOW | RTLD_LOCAL);
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void *retval = NULL;
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if (lib != NULL) {
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retval = dlsym(lib, sym);
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if (retval == NULL) {
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dlclose(lib);
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}
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}
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return retval;
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}
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#else
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#error Please define your platform.
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#endif
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static void
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SDL_InitDynamicAPILocked(void)
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{
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const char *libname = SDL_getenv_REAL("SDL_DYNAMIC_API");
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SDL_DYNAPI_ENTRYFN entry = SDL_DYNAPI_entry; /* funcs from here by default. */
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if (libname) {
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entry = (SDL_DYNAPI_ENTRYFN) get_sdlapi_entry(libname, "SDL_DYNAPI_entry");
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if (!entry) {
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/* !!! FIXME: fail to startup here instead? */
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/* !!! FIXME: definitely warn user. */
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/* Just fill in the function pointers from this library. */
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entry = SDL_DYNAPI_entry;
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}
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}
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if (entry(SDL_DYNAPI_VERSION, &jump_table, sizeof (jump_table)) < 0) {
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/* !!! FIXME: fail to startup here instead? */
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/* !!! FIXME: definitely warn user. */
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/* Just fill in the function pointers from this library. */
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if (entry != SDL_DYNAPI_entry) {
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if (!SDL_DYNAPI_entry(SDL_DYNAPI_VERSION, &jump_table, sizeof (jump_table))) {
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/* !!! FIXME: now we're screwed. Should definitely abort now. */
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}
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}
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}
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/* we intentionally never close the newly-loaded lib, of course. */
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}
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static void
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SDL_InitDynamicAPI(void)
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{
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/* So the theory is that every function in the jump table defaults to
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* calling this function, and then replaces itself with a version that
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* doesn't call this function anymore. But it's possible that, in an
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* extreme corner case, you can have a second thread hit this function
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* while the jump table is being initialized by the first.
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* In this case, a spinlock is really painful compared to what spinlocks
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* _should_ be used for, but this would only happen once, and should be
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* insanely rare, as you would have to spin a thread outside of SDL (as
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* SDL_CreateThread() would also call this function before building the
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* new thread).
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*/
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static SDL_bool already_initialized = SDL_FALSE;
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/* SDL_AtomicLock calls SDL mutex functions to emulate if
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SDL_ATOMIC_DISABLED, which we can't do here, so in such a
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configuration, you're on your own. */
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#if !SDL_ATOMIC_DISABLED
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static SDL_SpinLock lock = 0;
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SDL_AtomicLock_REAL(&lock);
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#endif
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if (!already_initialized) {
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SDL_InitDynamicAPILocked();
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already_initialized = SDL_TRUE;
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}
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#if !SDL_ATOMIC_DISABLED
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SDL_AtomicUnlock_REAL(&lock);
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#endif
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}
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#endif /* SDL_DYNAMIC_API */
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/* vi: set ts=4 sw=4 expandtab: */
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