1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
#include <kernel/OS.h>
#include <support/SupportDefs.h>
#include <errno.h>
/* ----------------------------------------------------------------------
* Fast locking mechanism described by Benoit Schillings (benoit@be.com)
* in the Be Developer's Newsletter, Issue #26 (http://www.be.com/).
*/
typedef struct benaphore {
sem_id _sem;
int32 _atom;
} benaphore_t;
static status_t benaphore_create( const char *name, benaphore_t *ben );
static status_t benaphore_destroy( benaphore_t *ben );
static status_t benaphore_lock( benaphore_t *ben );
static status_t benaphore_timedlock( benaphore_t *ben, bigtime_t micros );
static status_t benaphore_unlock( benaphore_t *ben );
static status_t benaphore_create( const char *name, benaphore_t *ben )
{
if( ben != NULL ) {
ben->_atom = 0;
ben->_sem = create_sem( 0, name );
if( ben->_sem < B_NO_ERROR ) {
return B_BAD_SEM_ID;
}
} else {
return EFAULT;
}
return EOK;
}
static status_t benaphore_destroy( benaphore_t *ben )
{
if( ben->_sem >= B_NO_ERROR ) {
status_t retval = benaphore_timedlock( ben, 0 );
if( retval == EOK || retval == EWOULDBLOCK ) {
status_t del_retval = delete_sem( ben->_sem );
return del_retval;
}
}
return B_BAD_SEM_ID;
}
static status_t benaphore_lock( benaphore_t *ben )
{
int32 prev = atomic_add( &(ben->_atom), 1 );
if( prev > 0 ) {
return acquire_sem( ben->_sem );
}
return EOK;
}
static status_t benaphore_timedlock( benaphore_t *ben, bigtime_t micros )
{
int32 prev = atomic_add( &(ben->_atom), 1 );
if( prev > 0 ) {
status_t retval = acquire_sem_etc( ben->_sem, 1, B_TIMEOUT, micros );
switch( retval ) {
case B_WOULD_BLOCK: /* Fall through... */
case B_TIMED_OUT:
return EWOULDBLOCK;
break;
case B_OK:
return EOK;
break;
default:
return retval;
break;
}
}
return EOK;
}
static status_t benaphore_unlock( benaphore_t *ben )
{
int32 prev = atomic_add( &(ben->_atom), -1 );
if( prev > 1 ) {
return release_sem( ben->_sem );
}
return EOK;
}
/* ----------------------------------------------------------------------
* Initialization.
*/
static void PyThread__init_thread( void )
{
/* Do nothing. */
return;
}
/* ----------------------------------------------------------------------
* Thread support.
*
* Only ANSI C, renamed functions here; you can't use K&R on BeOS,
* and there's no legacy thread module to support.
*/
static int32 thread_count = 0;
long PyThread_start_new_thread( void (*func)(void *), void *arg )
{
status_t success = 0;
thread_id tid;
char name[B_OS_NAME_LENGTH];
int32 this_thread;
dprintf(("PyThread_start_new_thread called\n"));
/* We are so very thread-safe... */
this_thread = atomic_add( &thread_count, 1 );
PyOS_snprintf(name, sizeof(name),
"python thread (%d)", this_thread );
tid = spawn_thread( (thread_func)func, name,
B_NORMAL_PRIORITY, arg );
if( tid > B_NO_ERROR ) {
success = resume_thread( tid );
}
return ( success == B_NO_ERROR ? tid : -1 );
}
long PyThread_get_thread_ident( void )
{
/* Presumed to return the current thread's ID... */
thread_id tid;
tid = find_thread( NULL );
return ( tid != B_NAME_NOT_FOUND ? tid : -1 );
}
void PyThread_exit_thread( void )
{
int32 threads;
dprintf(("PyThread_exit_thread called\n"));
/* Thread-safe way to read a variable without a mutex: */
threads = atomic_add( &thread_count, 0 );
if( threads == 0 ) {
/* No threads around, so exit main(). */
exit(0);
} else {
/* Oh, we're a thread, let's try to exit gracefully... */
exit_thread( B_NO_ERROR );
}
}
/* ----------------------------------------------------------------------
* Lock support.
*/
static int32 lock_count = 0;
PyThread_type_lock PyThread_allocate_lock( void )
{
benaphore_t *lock;
status_t retval;
char name[B_OS_NAME_LENGTH];
int32 this_lock;
dprintf(("PyThread_allocate_lock called\n"));
lock = (benaphore_t *)malloc( sizeof( benaphore_t ) );
if( lock == NULL ) {
/* TODO: that's bad, raise MemoryError */
return (PyThread_type_lock)NULL;
}
this_lock = atomic_add( &lock_count, 1 );
PyOS_snprintf(name, sizeof(name), "python lock (%d)", this_lock);
retval = benaphore_create( name, lock );
if( retval != EOK ) {
/* TODO: that's bad, raise an exception */
return (PyThread_type_lock)NULL;
}
dprintf(("PyThread_allocate_lock() -> %p\n", lock));
return (PyThread_type_lock) lock;
}
void PyThread_free_lock( PyThread_type_lock lock )
{
status_t retval;
dprintf(("PyThread_free_lock(%p) called\n", lock));
retval = benaphore_destroy( (benaphore_t *)lock );
if( retval != EOK ) {
/* TODO: that's bad, raise an exception */
return;
}
}
int PyThread_acquire_lock( PyThread_type_lock lock, int waitflag )
{
int success;
status_t retval;
dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));
if( waitflag ) {
retval = benaphore_lock( (benaphore_t *)lock );
} else {
retval = benaphore_timedlock( (benaphore_t *)lock, 0 );
}
if( retval == EOK ) {
success = 1;
} else {
success = 0;
/* TODO: that's bad, raise an exception */
}
dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success));
return success;
}
void PyThread_release_lock( PyThread_type_lock lock )
{
status_t retval;
dprintf(("PyThread_release_lock(%p) called\n", lock));
retval = benaphore_unlock( (benaphore_t *)lock );
if( retval != EOK ) {
/* TODO: that's bad, raise an exception */
return;
}
}
|
