1 /*****************************************************************************
2 * instance.c: VDPAU instance management for VLC
3 *****************************************************************************
4 * Copyright (C) 2013 Rémi Denis-Courmont
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU Lesser General Public License as published by
8 * the Free Software Foundation; either version 2.1 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with this program; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
19 *****************************************************************************/
20
21 #ifdef HAVE_CONFIG_H
22 # include <config.h>
23 #endif
24
25 #include <stdlib.h>
26 #include <stdint.h>
27 #include <assert.h>
28 #include <pthread.h>
29 #include <X11/Xlib.h>
30 #include <vlc_common.h>
31 #include "vlc_vdpau.h"
32
33 #pragma GCC visibility push(default)
34
35 typedef struct vdp_instance
36 {
37 Display *display;
38 vdp_t *vdp;
39 VdpDevice device;
40
41 int num; /**< X11 screen number */
42 char *name; /**< X11 display name */
43
44 uintptr_t refs; /**< Reference count */
45 struct vdp_instance *next;
46 } vdp_instance_t;
47
vdp_instance_create(const char * name,int num,vdp_instance_t ** pp)48 static VdpStatus vdp_instance_create(const char *name, int num,
49 vdp_instance_t **pp)
50 {
51 size_t namelen = (name != NULL) ? (strlen(name) + 1) : 0;
52 vdp_instance_t *vi = malloc(sizeof (*vi) + namelen);
53
54 if (unlikely(vi == NULL))
55 return VDP_STATUS_RESOURCES;
56
57 vi->display = XOpenDisplay(name);
58 if (vi->display == NULL)
59 {
60 free(vi);
61 return VDP_STATUS_ERROR;
62 }
63
64 vi->next = NULL;
65 if (name != NULL)
66 {
67 vi->name = (void *)(vi + 1);
68 memcpy(vi->name, name, namelen);
69 }
70 else
71 vi->name = NULL;
72 if (num >= 0)
73 vi->num = num;
74 else
75 vi->num = XDefaultScreen(vi->display);
76 vi->refs = 1;
77
78 VdpStatus err = vdp_create_x11(vi->display, vi->num,
79 &vi->vdp, &vi->device);
80 if (err != VDP_STATUS_OK)
81 {
82 XCloseDisplay(vi->display);
83 free(vi);
84 return err;
85 }
86 *pp = vi;
87 return VDP_STATUS_OK;
88 }
89
vdp_instance_destroy(vdp_instance_t * vi)90 static void vdp_instance_destroy(vdp_instance_t *vi)
91 {
92 vdp_device_destroy(vi->vdp, vi->device);
93 vdp_destroy_x11(vi->vdp);
94 XCloseDisplay(vi->display);
95 free(vi);
96 }
97
98 /** Compares two string pointers that might be NULL */
strnullcmp(const char * a,const char * b)99 static int strnullcmp(const char *a, const char *b)
100 {
101 if (b == NULL)
102 return a != NULL;
103 if (a == NULL)
104 return -1;
105 return strcmp(a, b);
106 }
107
vicmp(const char * name,int num,const vdp_instance_t * vi)108 static int vicmp(const char *name, int num, const vdp_instance_t *vi)
109 {
110 int val = strnullcmp(name, vi->name);
111 if (val)
112 return val;
113
114 if (num < 0)
115 num = XDefaultScreen(vi->display);
116 return num - vi->num;
117 }
118
119 static vdp_instance_t *list = NULL;
120
vdp_instance_lookup(const char * name,int num)121 static vdp_instance_t *vdp_instance_lookup(const char *name, int num)
122 {
123 vdp_instance_t *vi = NULL;
124
125 for (vi = list; vi != NULL; vi = vi->next)
126 {
127 int val = vicmp(name, num, vi);
128 if (val == 0)
129 {
130 assert(vi->refs < UINTPTR_MAX);
131 vi->refs++;
132 break;
133 }
134 }
135 return vi;
136 }
137
138 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
139
140 /** Finds an existing VDPAU instance for the given X11 display and screen.
141 * If not found, (try to) create a new one.
142 * @param display_name X11 display string, NULL for default
143 * @param snum X11 screen number, strictly negative for default
144 **/
vdp_get_x11(const char * display_name,int snum,vdp_t ** restrict vdpp,VdpDevice * restrict devicep)145 VdpStatus vdp_get_x11(const char *display_name, int snum,
146 vdp_t **restrict vdpp, VdpDevice *restrict devicep)
147 {
148 vdp_instance_t *vi, *vi2;
149 VdpStatus err = VDP_STATUS_RESOURCES;
150
151 if (display_name == NULL)
152 {
153 display_name = getenv("DISPLAY");
154 if (display_name == NULL)
155 return VDP_STATUS_ERROR;
156 }
157
158 pthread_mutex_lock(&lock);
159 vi = vdp_instance_lookup(display_name, snum);
160 pthread_mutex_unlock(&lock);
161 if (vi != NULL)
162 goto found;
163
164 err = vdp_instance_create(display_name, snum, &vi);
165 if (err != VDP_STATUS_OK)
166 return err;
167
168 pthread_mutex_lock(&lock);
169 vi2 = vdp_instance_lookup(display_name, snum);
170 if (unlikely(vi2 != NULL))
171 { /* Another thread created the instance (race condition corner case) */
172 pthread_mutex_unlock(&lock);
173 vdp_instance_destroy(vi);
174 vi = vi2;
175 }
176 else
177 {
178 vi->next = list;
179 list = vi;
180 pthread_mutex_unlock(&lock);
181 }
182 found:
183 *vdpp = vi->vdp;
184 *devicep = vi->device;
185 return VDP_STATUS_OK;
186 }
187
vdp_hold_x11(vdp_t * vdp,VdpDevice * restrict devp)188 vdp_t *vdp_hold_x11(vdp_t *vdp, VdpDevice *restrict devp)
189 {
190 vdp_instance_t *vi, **pp = &list;
191
192 pthread_mutex_lock(&lock);
193 for (;;)
194 {
195 vi = *pp;
196 assert(vi != NULL);
197 if (vi->vdp == vdp)
198 break;
199 pp = &vi->next;
200 }
201
202 assert(vi->refs < UINTPTR_MAX);
203 vi->refs++;
204 pthread_mutex_unlock(&lock);
205
206 if (devp != NULL)
207 *devp = vi->device;
208 return vdp;
209 }
210
vdp_release_x11(vdp_t * vdp)211 void vdp_release_x11(vdp_t *vdp)
212 {
213 vdp_instance_t *vi, **pp = &list;
214
215 pthread_mutex_lock(&lock);
216 for (;;)
217 {
218 vi = *pp;
219 assert(vi != NULL);
220 if (vi->vdp == vdp)
221 break;
222 pp = &vi->next;
223 }
224
225 assert(vi->refs > 0);
226 vi->refs--;
227 if (vi->refs > 0)
228 vi = NULL; /* Keep the instance for now */
229 else
230 *pp = vi->next; /* Unlink the instance */
231 pthread_mutex_unlock(&lock);
232
233 if (vi != NULL)
234 vdp_instance_destroy(vi);
235 }
236