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 #include <pthread.h>
37
38 #include "glxclient.h"
39 #include "glapi.h"
40 #include "glx_error.h"
41
42 /*
43 ** We setup some dummy structures here so that the API can be used
44 ** even if no context is current.
45 */
46
47 static GLubyte dummyBuffer[__GLX_BUFFER_LIMIT_SIZE];
48 static struct glx_context_vtable dummyVtable;
49 /*
50 ** Dummy context used by small commands when there is no current context.
51 ** All the
52 ** gl and glx entry points are designed to operate as nop's when using
53 ** the dummy context structure.
54 */
55 struct glx_context dummyContext = {
56 &dummyBuffer[0],
57 &dummyBuffer[0],
58 &dummyBuffer[0],
59 &dummyBuffer[__GLX_BUFFER_LIMIT_SIZE],
60 sizeof(dummyBuffer),
61 &dummyVtable
62 };
63
64 /*
65 * Current context management and locking
66 */
67
68 _X_HIDDEN pthread_mutex_t __glXmutex = PTHREAD_MUTEX_INITIALIZER;
69
70 # if defined( USE_ELF_TLS )
71
72 /**
73 * Per-thread GLX context pointer.
74 *
75 * \c __glXSetCurrentContext is written is such a way that this pointer can
76 * \b never be \c NULL. This is important! Because of this
77 * \c __glXGetCurrentContext can be implemented as trivial macro.
78 */
79 __THREAD_INITIAL_EXEC void *__glX_tls_Context = &dummyContext;
80
81 _X_HIDDEN void
__glXSetCurrentContext(struct glx_context * c)82 __glXSetCurrentContext(struct glx_context * c)
83 {
84 __glX_tls_Context = (c != NULL) ? c : &dummyContext;
85 }
86
87 # else
88
89 static pthread_once_t once_control = PTHREAD_ONCE_INIT;
90
91 /**
92 * Per-thread data key.
93 *
94 * Once \c init_thread_data has been called, the per-thread data key will
95 * take a value of \c NULL. As each new thread is created the default
96 * value, in that thread, will be \c NULL.
97 */
98 static pthread_key_t ContextTSD;
99
100 /**
101 * Initialize the per-thread data key.
102 *
103 * This function is called \b exactly once per-process (not per-thread!) to
104 * initialize the per-thread data key. This is ideally done using the
105 * \c pthread_once mechanism.
106 */
107 static void
init_thread_data(void)108 init_thread_data(void)
109 {
110 if (pthread_key_create(&ContextTSD, NULL) != 0) {
111 perror("pthread_key_create");
112 exit(-1);
113 }
114 }
115
116 _X_HIDDEN void
__glXSetCurrentContext(struct glx_context * c)117 __glXSetCurrentContext(struct glx_context * c)
118 {
119 pthread_once(&once_control, init_thread_data);
120 pthread_setspecific(ContextTSD, c);
121 }
122
123 _X_HIDDEN struct glx_context *
__glXGetCurrentContext(void)124 __glXGetCurrentContext(void)
125 {
126 void *v;
127
128 pthread_once(&once_control, init_thread_data);
129
130 v = pthread_getspecific(ContextTSD);
131 return (v == NULL) ? &dummyContext : (struct glx_context *) v;
132 }
133
134 # endif /* defined( USE_ELF_TLS ) */
135
136
137 _X_HIDDEN void
__glXSetCurrentContextNull(void)138 __glXSetCurrentContextNull(void)
139 {
140 __glXSetCurrentContext(&dummyContext);
141 #if defined(GLX_DIRECT_RENDERING)
142 _glapi_set_dispatch(NULL); /* no-op functions */
143 _glapi_set_context(NULL);
144 #endif
145 }
146
147 _GLX_PUBLIC GLXContext
glXGetCurrentContext(void)148 glXGetCurrentContext(void)
149 {
150 struct glx_context *cx = __glXGetCurrentContext();
151
152 if (cx == &dummyContext) {
153 return NULL;
154 }
155 else {
156 return (GLXContext) cx;
157 }
158 }
159
160 _GLX_PUBLIC GLXDrawable
glXGetCurrentDrawable(void)161 glXGetCurrentDrawable(void)
162 {
163 struct glx_context *gc = __glXGetCurrentContext();
164 return gc->currentDrawable;
165 }
166
167 /**
168 * Make a particular context current.
169 *
170 * \note This is in this file so that it can access dummyContext.
171 */
172 static Bool
MakeContextCurrent(Display * dpy,GLXDrawable draw,GLXDrawable read,GLXContext gc_user,int opcode)173 MakeContextCurrent(Display * dpy, GLXDrawable draw,
174 GLXDrawable read, GLXContext gc_user,
175 int opcode)
176 {
177 struct glx_context *gc = (struct glx_context *) gc_user;
178 struct glx_context *oldGC = __glXGetCurrentContext();
179
180 /* Make sure that the new context has a nonzero ID. In the request,
181 * a zero context ID is used only to mean that we bind to no current
182 * context.
183 */
184 if ((gc != NULL) && (gc->xid == None)) {
185 return GL_FALSE;
186 }
187
188 _glapi_check_multithread();
189
190 __glXLock();
191 if (oldGC == gc &&
192 gc->currentDrawable == draw && gc->currentReadable == read) {
193 __glXUnlock();
194 return True;
195 }
196
197 /* can't have only one be 0 */
198 if (!!draw != !!read) {
199 __glXUnlock();
200 __glXSendError(dpy, BadMatch, None, opcode, True);
201 return False;
202 }
203
204 if (oldGC != &dummyContext) {
205 if (--oldGC->thread_refcount == 0) {
206 oldGC->vtable->unbind(oldGC, gc);
207 oldGC->currentDpy = 0;
208 }
209 }
210
211 if (gc) {
212 /* Attempt to bind the context. We do this before mucking with
213 * gc and __glXSetCurrentContext to properly handle our state in
214 * case of an error.
215 *
216 * If an error occurs, set the Null context since we've already
217 * blown away our old context. The caller is responsible for
218 * figuring out how to handle setting a valid context.
219 */
220 if (gc->vtable->bind(gc, oldGC, draw, read) != Success) {
221 __glXSetCurrentContextNull();
222 __glXUnlock();
223 __glXSendError(dpy, GLXBadContext, None, opcode, False);
224 return GL_FALSE;
225 }
226
227 if (gc->thread_refcount == 0) {
228 gc->currentDpy = dpy;
229 gc->currentDrawable = draw;
230 gc->currentReadable = read;
231 }
232 gc->thread_refcount++;
233 __glXSetCurrentContext(gc);
234 } else {
235 __glXSetCurrentContextNull();
236 }
237
238 if (oldGC->thread_refcount == 0 && oldGC != &dummyContext && oldGC->xid == None) {
239 /* We are switching away from a context that was
240 * previously destroyed, so we need to free the memory
241 * for the old handle. */
242 oldGC->vtable->destroy(oldGC);
243 }
244
245 __glXUnlock();
246
247 return GL_TRUE;
248 }
249
250 _GLX_PUBLIC Bool
glXMakeCurrent(Display * dpy,GLXDrawable draw,GLXContext gc)251 glXMakeCurrent(Display * dpy, GLXDrawable draw, GLXContext gc)
252 {
253 return MakeContextCurrent(dpy, draw, draw, gc, X_GLXMakeCurrent);
254 }
255
256 _GLX_PUBLIC Bool
glXMakeContextCurrent(Display * dpy,GLXDrawable d,GLXDrawable r,GLXContext ctx)257 glXMakeContextCurrent(Display *dpy, GLXDrawable d, GLXDrawable r,
258 GLXContext ctx)
259 {
260 return MakeContextCurrent(dpy, d, r, ctx, X_GLXMakeContextCurrent);
261 }
262
263 _GLX_PUBLIC Bool
glXMakeCurrentReadSGI(Display * dpy,GLXDrawable d,GLXDrawable r,GLXContext ctx)264 glXMakeCurrentReadSGI(Display *dpy, GLXDrawable d, GLXDrawable r,
265 GLXContext ctx)
266 {
267 return MakeContextCurrent(dpy, d, r, ctx, X_GLXvop_MakeCurrentReadSGI);
268 }
269