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
|
/*
Copyright 2011 Kristian Nielsen and Monty Program Ab
2015, 2022 MariaDB Corporation AB
This file is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU General Public License
along with this. If not, see <http://www.gnu.org/licenses/>.
*/
/*
Simple API for spawning a co-routine, to be used for async libmysqlclient.
Idea is that by implementing this interface using whatever facilities are
available for given platform, we can use the same code for the generic
libmysqlclient-async code.
(This particular implementation uses Posix ucontext swapcontext().)
*/
#ifdef _WIN32
#define MY_CONTEXT_USE_WIN32_FIBERS 1
#elif defined(__GNUC__) && __GNUC__ >= 3 && defined(__x86_64__) && !defined(__ILP32__)
#define MY_CONTEXT_USE_X86_64_GCC_ASM
#elif defined(__GNUC__) && __GNUC__ >= 3 && defined(__i386__)
#define MY_CONTEXT_USE_I386_GCC_ASM
#elif defined(HAVE_UCONTEXT_H)
#define MY_CONTEXT_USE_UCONTEXT
#else
#define MY_CONTEXT_DISABLE
#endif
#ifdef MY_CONTEXT_USE_WIN32_FIBERS
struct my_context {
void (*user_func)(void *);
void *user_arg;
void *app_fiber;
void *lib_fiber;
int return_value;
#ifndef DBUG_OFF
void *dbug_state;
#endif
};
#endif
#ifdef MY_CONTEXT_USE_UCONTEXT
#include <ucontext.h>
struct my_context {
void (*user_func)(void *);
void *user_data;
void *stack;
size_t stack_size;
ucontext_t base_context;
ucontext_t spawned_context;
int active;
#ifdef HAVE_VALGRIND
unsigned int valgrind_stack_id;
#endif
#ifndef DBUG_OFF
void *dbug_state;
#endif
};
#endif
#ifdef MY_CONTEXT_USE_X86_64_GCC_ASM
#include <stdint.h>
struct my_context {
uint64_t save[9];
void *stack_top;
void *stack_bot;
#ifdef HAVE_VALGRIND
unsigned int valgrind_stack_id;
#endif
#ifndef DBUG_OFF
void *dbug_state;
#endif
};
#endif
#ifdef MY_CONTEXT_USE_I386_GCC_ASM
#include <stdint.h>
struct my_context {
uint64_t save[7];
void *stack_top;
void *stack_bot;
#ifdef HAVE_VALGRIND
unsigned int valgrind_stack_id;
#endif
#ifndef DBUG_OFF
void *dbug_state;
#endif
};
#endif
#ifdef MY_CONTEXT_DISABLE
struct my_context {
int dummy;
};
#endif
/*
Initialize an asynchronous context object.
Returns 0 on success, non-zero on failure.
*/
extern int my_context_init(struct my_context *c, size_t stack_size);
/* Free an asynchronous context object, deallocating any resources used. */
extern void my_context_destroy(struct my_context *c);
/*
Spawn an asynchronous context. The context will run the supplied user
function, passing the supplied user data pointer.
The context must have been initialised with my_context_init() prior to
this call.
The user function may call my_context_yield(), which will cause this
function to return 1. Then later my_context_continue() may be called, which
will resume the asynchronous context by returning from the previous
my_context_yield() call.
When the user function returns, this function returns 0.
In case of error, -1 is returned.
*/
extern int my_context_spawn(struct my_context *c, void (*f)(void *), void *d);
/*
Suspend an asynchronous context started with my_context_spawn.
When my_context_yield() is called, execution immediately returns from the
last my_context_spawn() or my_context_continue() call. Then when later
my_context_continue() is called, execution resumes by returning from this
my_context_yield() call.
Returns 0 if ok, -1 in case of error.
*/
extern int my_context_yield(struct my_context *c);
/*
Resume an asynchronous context. The context was spawned by
my_context_spawn(), and later suspended inside my_context_yield().
The asynchronous context may be repeatedly suspended with
my_context_yield() and resumed with my_context_continue().
Each time it is suspended, this function returns 1. When the originally
spawned user function returns, this function returns 0.
In case of error, -1 is returned.
*/
extern int my_context_continue(struct my_context *c);
struct st_ma_pvio;
struct mysql_async_context {
/*
This is set to the value that should be returned from foo_start() or
foo_cont() when a call is suspended.
*/
unsigned int events_to_wait_for;
/*
It is also set to the event(s) that triggered when a suspended call is
resumed, eg. whether we woke up due to connection completed or timeout
in mysql_real_connect_cont().
*/
unsigned int events_occurred;
/*
This is set to the result of the whole asynchronous operation when it
completes. It uses a union, as different calls have different return
types.
*/
union {
void *r_ptr;
const void *r_const_ptr;
int r_int;
my_bool r_my_bool;
} ret_result;
/*
The timeout value (in millisecods), for suspended calls that need to wake
up on a timeout (eg. mysql_real_connect_start().
*/
unsigned int timeout_value;
/*
This flag is set when we are executing inside some asynchronous call
foo_start() or foo_cont(). It is used to decide whether to use the
synchronous or asynchronous version of calls that may block such as
recv().
Note that this flag is not set when a call is suspended, eg. after
returning from foo_start() and before re-entering foo_cont().
*/
my_bool active;
/*
This flag is set when an asynchronous operation is in progress, but
suspended. Ie. it is set when foo_start() or foo_cont() returns because
the operation needs to block, suspending the operation.
It is used to give an error (rather than crash) if the application
attempts to call some foo_cont() method when no suspended operation foo is
in progress.
*/
my_bool suspended;
/*
If non-NULL, this is a pointer to a callback hook that will be invoked with
the user data argument just before the context is suspended, and just after
it is resumed.
*/
struct st_ma_pvio *pvio;
void (*suspend_resume_hook)(my_bool suspend, void *user_data);
void *suspend_resume_hook_user_data;
/* If non-NULL, this is a poitner to the result of getaddrinfo() currently
* under traversal in pvio_socket_connect(). It gets reset to NULL when a
* connection has been established to a server. The main objective is to
* free this memory resource in mysql_close() while an initiated connection
* has not been established. */
struct addrinfo* pending_gai_res;
/*
This is used to save the execution contexts so that we can suspend an
operation and switch back to the application context, to resume the
suspended context later when the application re-invokes us with
foo_cont().
*/
struct my_context async_context;
};
|
