src/glx/glxcurrent.c

   1 /*
   2  * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
   3  * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice including the dates of first publication and
  13  * either this permission notice or a reference to
  14  * http://oss.sgi.com/projects/FreeB/
  15  * shall be included in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  21  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
  22  * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  *
  25  * Except as contained in this notice, the name of Silicon Graphics, Inc.
  26  * shall not be used in advertising or otherwise to promote the sale, use or
  27  * other dealings in this Software without prior written authorization from
  28  * Silicon Graphics, Inc.
  29  */
  30
  31 /**
  32  * \file glxcurrent.c
  33  * Client-side GLX interface for current context management.
  34  */
  35
  36 #ifdef PTHREADS
  37 #include <pthread.h>
  38 #endif
  39
  40 #include "glxclient.h"
  41 #ifdef GLX_USE_APPLEGL
  42 #include <stdlib.h>
  43
  44 #include "apple_glx.h"
  45 #include "apple_glx_context.h"
  46 #else
  47 #include "glapi.h"
  48 #endif
  49
  50 /*
  51 ** We setup some dummy structures here so that the API can be used
  52 ** even if no context is current.
  53 */
  54
  55 static GLubyte dummyBuffer[__GLX_BUFFER_LIMIT_SIZE];
  56 static struct glx_context_vtable dummyVtable;
  57 /*
  58 ** Dummy context used by small commands when there is no current context.
  59 ** All the
  60 ** gl and glx entry points are designed to operate as nop's when using
  61 ** the dummy context structure.
  62 */
  63 struct glx_context dummyContext = {
  64    &dummyBuffer[0],
  65    &dummyBuffer[0],
  66    &dummyBuffer[0],
  67    &dummyBuffer[__GLX_BUFFER_LIMIT_SIZE],
  68    sizeof(dummyBuffer),
  69    &dummyVtable
  70 };
  71
  72 /*
  73  * Current context management and locking
  74  */
  75
  76 #if defined( PTHREADS )
  77
  78 _X_HIDDEN pthread_mutex_t __glXmutex = PTHREAD_MUTEX_INITIALIZER;
  79
  80 # if defined( GLX_USE_TLS )
  81
  82 /**
  83  * Per-thread GLX context pointer.
  84  *
  85  * \c __glXSetCurrentContext is written is such a way that this pointer can
  86  * \b never be \c NULL.  This is important!  Because of this
  87  * \c __glXGetCurrentContext can be implemented as trivial macro.
  88  */
  89 __thread void *__glX_tls_Context __attribute__ ((tls_model("initial-exec")))
  90    = &dummyContext;
  91
  92 _X_HIDDEN void
  93 __glXSetCurrentContext(struct glx_context * c)
  94 {
  95    __glX_tls_Context = (c != NULL) ? c : &dummyContext;
  96 }
  97
  98 # else
  99
 100 static pthread_once_t once_control = PTHREAD_ONCE_INIT;
 101
 102 /**
 103  * Per-thread data key.
 104  *
 105  * Once \c init_thread_data has been called, the per-thread data key will
 106  * take a value of \c NULL.  As each new thread is created the default
 107  * value, in that thread, will be \c NULL.
 108  */
 109 static pthread_key_t ContextTSD;
 110
 111 /**
 112  * Initialize the per-thread data key.
 113  *
 114  * This function is called \b exactly once per-process (not per-thread!) to
 115  * initialize the per-thread data key.  This is ideally done using the
 116  * \c pthread_once mechanism.
 117  */
 118 static void
 119 init_thread_data(void)
 120 {
 121    if (pthread_key_create(&ContextTSD, NULL) != 0) {
 122       perror("pthread_key_create");
 123       exit(-1);
 124    }
 125 }
 126
 127 _X_HIDDEN void
 128 __glXSetCurrentContext(struct glx_context * c)
 129 {
 130    pthread_once(&once_control, init_thread_data);
 131    pthread_setspecific(ContextTSD, c);
 132 }
 133
 134 _X_HIDDEN struct glx_context *
 135 __glXGetCurrentContext(void)
 136 {
 137    void *v;
 138
 139    pthread_once(&once_control, init_thread_data);
 140
 141    v = pthread_getspecific(ContextTSD);
 142    return (v == NULL) ? &dummyContext : (struct glx_context *) v;
 143 }
 144
 145 # endif /* defined( GLX_USE_TLS ) */
 146
 147 #elif defined( THREADS )
 148
 149 #error Unknown threading method specified.
 150
 151 #else
 152
 153 /* not thread safe */
 154 _X_HIDDEN struct glx_context *__glXcurrentContext = &dummyContext;
 155
 156 #endif
 157
 158
 159 _X_HIDDEN void
 160 __glXSetCurrentContextNull(void)
 161 {
 162    __glXSetCurrentContext(&dummyContext);
 163 #ifndef GLX_USE_APPLEGL
 164 #if defined(GLX_DIRECT_RENDERING) && !defined(GLX_USE_APPLEGL)
 165    _glapi_set_dispatch(NULL);   /* no-op functions */
 166    _glapi_set_context(NULL);
 167 #endif
 168 #endif
 169 }
 170
 171 _X_EXPORT GLXContext
 172 glXGetCurrentContext(void)
 173 {
 174    struct glx_context *cx = __glXGetCurrentContext();
 175
 176    if (cx == &dummyContext) {
 177       return NULL;
 178    }
 179    else {
 180       return (GLXContext) cx;
 181    }
 182 }
 183
 184 _X_EXPORT GLXDrawable
 185 glXGetCurrentDrawable(void)
 186 {
 187    struct glx_context *gc = __glXGetCurrentContext();
 188    return gc->currentDrawable;
 189 }
 190
 191 static void
 192 __glXGenerateError(Display * dpy, XID resource,
 193                    BYTE errorCode, CARD16 minorCode)
 194 {
 195    xError error;
 196
 197    error.errorCode = errorCode;
 198    error.resourceID = resource;
 199    error.sequenceNumber = dpy->request;
 200    error.type = X_Error;
 201    error.majorCode = __glXSetupForCommand(dpy);
 202    error.minorCode = minorCode;
 203    _XError(dpy, &error);
 204 }
 205
 206 /**
 207  * Make a particular context current.
 208  *
 209  * \note This is in this file so that it can access dummyContext.
 210  */
 211 static Bool
 212 MakeContextCurrent(Display * dpy, GLXDrawable draw,
 213                    GLXDrawable read, GLXContext gc_user)
 214 {
 215    struct glx_context *gc = (struct glx_context *) gc_user;
 216    struct glx_context *oldGC = __glXGetCurrentContext();
 217    int ret = Success;
 218
 219 #ifndef GLX_USE_APPLEGL
 220    /* XXX: If this is left out, then libGL ends up not having this
 221     * symbol, and drivers using it fail to load.  Compare the
 222     * implementation of this symbol to _glapi_noop_enable_warnings(),
 223     * though, which gets into the library despite no callers, the same
 224     * prototypes, and the same compile flags to the files containing
 225     * them.  Moving the definition to glapi_nop.c gets it into the
 226     * library, though.
 227     */
 228    (void)_glthread_GetID();
 229 #endif
 230
 231    /* Make sure that the new context has a nonzero ID.  In the request,
 232     * a zero context ID is used only to mean that we bind to no current
 233     * context.
 234     */
 235    if ((gc != NULL) && (gc->xid == None)) {
 236       return GL_FALSE;
 237    }
 238
 239    if (gc == NULL && (draw != None || read != None)) {
 240       __glXGenerateError(dpy, (draw != None) ? draw : read,
 241                          BadMatch, X_GLXMakeContextCurrent);
 242       return False;
 243    }
 244    if (gc != NULL && (draw == None || read == None)) {
 245       __glXGenerateError(dpy, None, BadMatch, X_GLXMakeContextCurrent);
 246       return False;
 247    }
 248
 249 #ifndef GLX_USE_APPLEGL
 250    _glapi_check_multithread();
 251 #endif
 252
 253    __glXLock();
 254    if (oldGC == gc &&
 255        gc->currentDrawable == draw && gc->currentReadable == read) {
 256       __glXUnlock();
 257       return True;
 258    }
 259
 260    if (oldGC != &dummyContext) {
 261       if (--oldGC->thread_refcount == 0) {
 262          oldGC->vtable->unbind(oldGC, gc);
 263          oldGC->currentDpy = 0;
 264          oldGC->currentDrawable = None;
 265          oldGC->currentReadable = None;
 266
 267          if (oldGC->xid == None && oldGC != gc) {
 268             /* We are switching away from a context that was
 269              * previously destroyed, so we need to free the memory
 270              * for the old handle. */
 271             oldGC->vtable->destroy(oldGC);
 272          }
 273       }
 274    }
 275
 276    if (gc) {
 277       if (gc->thread_refcount++ == 0) {
 278          gc->currentDpy = dpy;
 279          gc->currentDrawable = draw;
 280          gc->currentReadable = read;
 281       }
 282       __glXSetCurrentContext(gc);
 283       ret = gc->vtable->bind(gc, oldGC, draw, read);
 284    } else {
 285       __glXSetCurrentContextNull();
 286    }
 287
 288    __glXUnlock();
 289
 290    if (ret) {
 291       __glXGenerateError(dpy, None, ret, X_GLXMakeContextCurrent);
 292       return GL_FALSE;
 293    }
 294
 295    return GL_TRUE;
 296 }
 297
 298
 299 _X_EXPORT Bool
 300 glXMakeCurrent(Display * dpy, GLXDrawable draw, GLXContext gc)
 301 {
 302    return MakeContextCurrent(dpy, draw, draw, gc);
 303 }
 304
 305 _X_EXPORT
 306 GLX_ALIAS(Bool, glXMakeCurrentReadSGI,
 307           (Display * dpy, GLXDrawable d, GLXDrawable r, GLXContext ctx),
 308           (dpy, d, r, ctx), MakeContextCurrent)
 309
 310 _X_EXPORT
 311 GLX_ALIAS(Bool, glXMakeContextCurrent,
 312           (Display * dpy, GLXDrawable d, GLXDrawable r,
 313            GLXContext ctx), (dpy, d, r, ctx), MakeContextCurrent)