1 | /* |
1 | /* |
2 | iom.C -- I/O multiplexor |
2 | iom.C -- generic I/O multiplexer |
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3 | Copyright (C) 2003, 2004 Marc Lehmann <pcg@goof.com> |
3 | |
4 | |
4 | This program is free software; you can redistribute it and/or modify |
5 | This program is free software; you can redistribute it and/or modify |
5 | it under the terms of the GNU General Public License as published by |
6 | it under the terms of the GNU General Public License as published by |
6 | the Free Software Foundation; either version 2 of the License, or |
7 | the Free Software Foundation; either version 2 of the License, or |
7 | (at your option) any later version. |
8 | (at your option) any later version. |
… | |
… | |
14 | You should have received a copy of the GNU General Public License |
15 | You should have received a copy of the GNU General Public License |
15 | along with this program; if not, write to the Free Software |
16 | along with this program; if not, write to the Free Software |
16 | Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
17 | Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
17 | */ |
18 | */ |
18 | |
19 | |
19 | #include "config.h" |
20 | #include "iom.h" |
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21 | |
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22 | #include <cstdio> |
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23 | #include <cstdlib> |
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24 | #include <cerrno> |
20 | |
25 | |
21 | #include <sys/time.h> |
26 | #include <sys/time.h> |
22 | |
27 | |
23 | #include <algorithm> |
28 | #include <assert.h> |
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29 | |
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30 | #if 1 // older unices need these includes for select (2) |
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31 | # include <unistd.h> |
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32 | # include <sys/types.h> |
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33 | # include <time.h> |
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34 | #endif |
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35 | |
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36 | // for IOM_SIG |
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37 | #if IOM_SIG |
24 | #include <functional> |
38 | # include <csignal> |
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39 | # include <fcntl.h> |
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40 | #endif |
25 | |
41 | |
26 | #include "slog.h" |
42 | // if the BSDs would at least be marginally POSIX-compatible.. *sigh* |
27 | #include "iom.h" |
43 | // until that happens, sys/select.h must come last |
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44 | #include <sys/select.h> |
28 | |
45 | |
29 | inline bool lowest_first (const time_watcher *a, const time_watcher *b) |
46 | // TSTAMP_MAX must still fit into a positive struct timeval |
30 | { |
47 | #define TSTAMP_MAX (double)(1UL<<31) |
31 | return a->at > b->at; |
48 | |
32 | } |
49 | #define TIMEVAL timeval |
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50 | #define TV_FRAC tv_usec |
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51 | #define TV_MULT 1000000L |
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52 | |
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53 | #if IOM_IO |
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54 | static io_manager_vec<io_watcher> iow; |
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55 | #endif |
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56 | #if IOM_CHECK |
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57 | static io_manager_vec<check_watcher> cw; |
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58 | #endif |
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59 | #if IOM_TIME |
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60 | static io_manager_vec<time_watcher> tw; |
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61 | #endif |
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62 | #if IOM_IDLE |
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63 | static io_manager_vec<idle_watcher> iw; |
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64 | #endif |
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65 | #if IOM_SIG |
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66 | static int sigpipe[2]; // signal signalling pipe |
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67 | static sigset_t sigs; |
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68 | struct sig_vec : io_manager_vec<sig_watcher> { |
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69 | int pending; |
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70 | sig_vec () |
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71 | : pending (false) |
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72 | { } |
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73 | }; |
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74 | static vector<sig_vec *> sw; |
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75 | #endif |
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76 | |
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77 | // this is a dummy time watcher to ensure that the first |
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78 | // time watcher is _always_ valid, this gets rid of a lot |
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79 | // of null-pointer-checks |
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80 | // (must come _before_ iom is being defined) |
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81 | static struct tw0 : time_watcher |
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82 | { |
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83 | void cb (time_watcher &w) |
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84 | { |
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85 | // should never get called |
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86 | // reached end-of-time, or tstamp has a bogus definition, |
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87 | // or compiler initialisation order broken, or something else :) |
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88 | abort (); |
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89 | } |
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90 | |
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91 | tw0 () |
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92 | : time_watcher (this, &tw0::cb) |
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93 | { } |
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94 | } tw0; |
33 | |
95 | |
34 | tstamp NOW; |
96 | tstamp NOW; |
35 | |
97 | |
36 | io_manager iom; |
98 | #if IOM_TIME |
37 | |
99 | tstamp io_manager::now () |
38 | void time_watcher::set (tstamp when) |
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39 | { |
100 | { |
40 | at = when; |
101 | struct timeval tv; |
41 | |
102 | |
42 | if (registered) |
103 | gettimeofday (&tv, 0); |
43 | iom.reschedule_time_watchers (); |
104 | return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.; |
44 | else |
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45 | iom.reg (this); |
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46 | } |
105 | } |
47 | |
106 | |
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107 | void io_manager::set_now () |
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108 | { |
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109 | NOW = now (); |
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110 | } |
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111 | #endif |
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112 | |
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113 | static bool iom_valid; |
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114 | |
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115 | // used for initialisation only |
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116 | static struct init { |
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117 | init () |
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118 | { |
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119 | #if IOM_SIG |
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120 | sigemptyset (&sigs); |
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121 | |
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122 | if (pipe (sigpipe)) |
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123 | { |
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124 | perror ("io_manager: unable to create signal pipe, aborting."); |
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125 | abort (); |
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126 | } |
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127 | |
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128 | fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC); |
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129 | fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC); |
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130 | #endif |
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131 | |
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132 | iom_valid = true; |
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133 | |
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134 | #if IOM_TIME |
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135 | io_manager::set_now (); |
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136 | |
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137 | tw0.start (TSTAMP_MAX); |
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138 | #endif |
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139 | } |
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140 | |
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141 | static void required (); |
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142 | } init; |
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143 | |
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144 | void |
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145 | init::required () |
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146 | { |
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147 | if (!iom_valid) |
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148 | { |
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149 | write (2, "io_manager: early registration attempt, aborting.\n", |
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150 | sizeof ("io_manager: early registration attempt, aborting.\n") - 1); |
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151 | abort (); |
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152 | } |
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153 | } |
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154 | |
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155 | template<class watcher> |
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156 | void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue) |
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157 | { |
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158 | init::required (); |
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159 | |
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160 | if (!w.active) |
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161 | { |
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162 | queue.push_back (&w); |
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163 | w.active = queue.size (); |
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164 | } |
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165 | } |
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166 | |
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167 | template<class watcher> |
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168 | void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue) |
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169 | { |
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170 | if (!iom_valid) |
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171 | return; |
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172 | |
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173 | if (w.active) |
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174 | { |
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175 | queue [w.active - 1] = 0; |
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176 | w.active = 0; |
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177 | } |
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178 | } |
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179 | |
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180 | #if IOM_TIME |
48 | void time_watcher::trigger () |
181 | void time_watcher::trigger () |
49 | { |
182 | { |
50 | call (at); |
183 | call (*this); |
51 | |
184 | io_manager::reg (*this); |
52 | if (registered) |
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53 | iom.reschedule_time_watchers (); |
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54 | else |
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55 | iom.reg (this); |
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56 | } |
185 | } |
57 | |
186 | |
58 | void time_watcher::start () |
187 | void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); } |
59 | { |
188 | void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); } |
60 | if (!registered) |
189 | #endif |
61 | iom.reg (this); |
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62 | } |
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63 | |
190 | |
64 | void io_manager::reg (int fd, short events, io_watcher *w) |
191 | #if IOM_IO |
65 | { |
192 | void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); } |
66 | pollfd pfd; |
193 | void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); } |
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194 | #endif |
67 | |
195 | |
68 | pfd.fd = fd; |
196 | #if IOM_CHECK |
69 | pfd.events = events; |
197 | void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); } |
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198 | void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); } |
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199 | #endif |
70 | |
200 | |
71 | pfs.push_back (pfd); |
201 | #if IOM_IDLE |
72 | iow.push_back (w); |
202 | void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); } |
73 | } |
203 | void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); } |
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204 | #endif |
74 | |
205 | |
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206 | #if IOM_SIG |
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207 | static void |
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208 | sighandler (int signum) |
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209 | { |
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210 | sw [signum - 1]->pending = true; |
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211 | |
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212 | // we use a pipe for signal notifications, as most current |
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213 | // OSes (Linux...) do not implement pselect correctly. ugh. |
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214 | char ch = signum; // actual content not used |
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215 | write (sigpipe[1], &ch, 1); |
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216 | } |
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217 | |
75 | void io_manager::unreg (io_watcher *w) |
218 | void io_manager::reg (sig_watcher &w) |
76 | { |
219 | { |
77 | unsigned int sz = iow.size (); |
220 | assert (0 < w.signum); |
78 | unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin (); |
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79 | |
221 | |
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222 | sw.reserve (w.signum); |
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223 | |
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224 | while (sw.size () < w.signum) // pathetic |
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225 | sw.push_back (0); |
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226 | |
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227 | sig_vec *&sv = sw[w.signum - 1]; |
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228 | |
80 | if (i != sz) |
229 | if (!sv) |
81 | { |
230 | { |
82 | if (sz == 1) |
231 | sv = new sig_vec; |
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232 | |
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233 | sigaddset (&sigs, w.signum); |
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234 | sigprocmask (SIG_BLOCK, &sigs, NULL); |
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235 | |
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236 | struct sigaction sa; |
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237 | sa.sa_handler = sighandler; |
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238 | sigfillset (&sa.sa_mask); |
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239 | sa.sa_flags = SA_RESTART; |
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240 | |
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241 | if (sigaction (w.signum, &sa, 0)) |
83 | { |
242 | { |
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243 | perror ("io_manager: error while installing signal handler, ignoring."); |
84 | pfs.clear (); |
244 | abort (); |
85 | iow.clear (); |
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86 | } |
245 | } |
87 | else if (i == sz - 1) |
246 | |
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247 | } |
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248 | |
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249 | io_manager::reg (w, *sv); |
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250 | } |
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251 | |
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252 | void io_manager::unreg (sig_watcher &w) |
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253 | { |
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254 | if (!w.active) |
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255 | return; |
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256 | |
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257 | assert (0 < w.signum && w.signum <= sw.size ()); |
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258 | |
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259 | io_manager::unreg (w, *sw[w.signum - 1]); |
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260 | } |
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261 | |
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262 | void sig_watcher::start (int signum) |
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263 | { |
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264 | stop (); |
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265 | this->signum = signum; |
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266 | io_manager::reg (*this); |
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267 | } |
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268 | #endif |
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269 | |
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270 | void io_manager::loop () |
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271 | { |
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272 | init::required (); |
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273 | |
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274 | #if IOM_TIME |
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275 | set_now (); |
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276 | #endif |
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277 | |
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278 | for (;;) |
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279 | { |
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280 | |
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281 | #if IOM_TIME |
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282 | // call pending time watchers |
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283 | { |
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284 | bool activity; |
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285 | |
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286 | do |
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287 | { |
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288 | activity = false; |
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289 | |
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290 | for (int i = tw.size (); i--; ) |
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291 | if (!tw[i]) |
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292 | tw.erase_unordered (i); |
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293 | else if (tw[i]->at <= NOW) |
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294 | { |
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295 | time_watcher &w = *tw[i]; |
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296 | |
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297 | unreg (w); |
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298 | w.call (w); |
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299 | |
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300 | activity = true; |
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301 | } |
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302 | } |
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303 | while (activity); |
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304 | } |
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305 | #endif |
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306 | |
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307 | #if IOM_CHECK |
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308 | // call all check watchers |
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309 | for (int i = cw.size (); i--; ) |
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310 | if (!cw[i]) |
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311 | cw.erase_unordered (i); |
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312 | else |
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313 | cw[i]->call (*cw[i]); |
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314 | #endif |
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315 | |
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316 | struct TIMEVAL *to = 0; |
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317 | struct TIMEVAL tval; |
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318 | |
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319 | #if IOM_IDLE |
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320 | if (iw.size ()) |
88 | { |
321 | { |
89 | iow.pop_back (); |
322 | tval.tv_sec = 0; |
90 | pfs.pop_back (); |
323 | tval.TV_FRAC = 0; |
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324 | to = &tval; |
91 | } |
325 | } |
92 | else |
326 | else |
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327 | #endif |
93 | { |
328 | { |
94 | iow[i] = iow[sz - 1]; iow.pop_back (); |
329 | #if IOM_TIME |
95 | pfs[i] = pfs[sz - 1]; pfs.pop_back (); |
330 | // find earliest active watcher |
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331 | time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times |
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332 | |
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333 | for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); ) |
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334 | if (*i && (*i)->at < next->at) |
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335 | next = *i; |
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336 | |
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337 | if (next->at > NOW && next != tw[0]) |
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338 | { |
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339 | double diff = next->at - NOW; |
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340 | tval.tv_sec = (int)diff; |
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341 | tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT); |
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342 | to = &tval; |
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343 | } |
96 | } |
344 | } |
97 | } |
345 | #endif |
98 | } |
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99 | |
346 | |
100 | void io_manager::reschedule_time_watchers () |
347 | #if IOM_IO || IOM_SIG |
101 | { |
348 | fd_set rfd, wfd; |
102 | make_heap (tw.begin (), tw.end (), lowest_first); |
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103 | } |
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104 | |
349 | |
105 | void io_manager::reg (time_watcher *w) |
350 | FD_ZERO (&rfd); |
106 | { |
351 | FD_ZERO (&wfd); |
107 | if (w->registered) |
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108 | slog (L_CRIT, "FATAL: io_manager::reg(time_watcher) called on already-registered watcher"); |
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109 | |
352 | |
110 | w->registered = true; |
353 | int fds = 0; |
111 | |
354 | |
112 | tw.push_back (w); |
355 | # if IOM_IO |
113 | push_heap (tw.begin (), tw.end (), lowest_first); |
356 | for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); ) |
114 | } |
357 | if (*i) |
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358 | { |
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359 | if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); |
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360 | if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); |
115 | |
361 | |
116 | void io_manager::unreg (time_watcher *w) |
362 | if ((*i)->fd >= fds) fds = (*i)->fd + 1; |
117 | { |
363 | } |
118 | if (w->registered) |
364 | # endif |
119 | { |
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120 | unsigned int sz = tw.size (); |
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121 | unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin (); |
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122 | |
365 | |
123 | if (i != sz) |
366 | if (!to && !fds) //TODO: also check idle_watchers and check_watchers? |
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367 | break; // no events |
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368 | |
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369 | # if IOM_SIG |
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370 | FD_SET (sigpipe[0], &rfd); |
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371 | if (sigpipe[0] >= fds) fds = sigpipe[0] + 1; |
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372 | # endif |
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373 | |
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374 | # if IOM_SIG |
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375 | // there is no race, as we use a pipe for signals, so select |
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376 | // will return if a signal is caught. |
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377 | sigprocmask (SIG_UNBLOCK, &sigs, NULL); |
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378 | # endif |
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379 | fds = select (fds, &rfd, &wfd, NULL, to); |
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380 | # if IOM_SIG |
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381 | sigprocmask (SIG_BLOCK, &sigs, NULL); |
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382 | # endif |
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383 | |
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384 | # if IOM_TIME |
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385 | set_now (); |
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386 | # endif |
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387 | |
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388 | if (fds > 0) |
124 | { |
389 | { |
125 | if (i != sz - 1) |
390 | # if IOM_SIG |
126 | tw[i] = tw[sz - 1]; |
391 | if (FD_ISSET (sigpipe[0], &rfd)) |
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392 | { |
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393 | char ch; |
127 | |
394 | |
128 | tw.pop_back (); |
395 | while (read (sigpipe[0], &ch, 1) > 0) |
129 | reschedule_time_watchers (); |
396 | ; |
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397 | |
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398 | for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); ) |
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399 | if (*svp && (*svp)->pending) |
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400 | { |
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401 | sig_vec &sv = **svp; |
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402 | for (int i = sv.size (); i--; ) |
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403 | if (!sv[i]) |
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404 | sv.erase_unordered (i); |
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405 | else |
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406 | sv[i]->call (*sv[i]); |
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407 | |
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408 | sv.pending = false; |
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409 | } |
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410 | } |
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411 | # endif |
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412 | |
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413 | # if IOM_IO |
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414 | for (int i = iow.size (); i--; ) |
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415 | if (!iow[i]) |
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416 | iow.erase_unordered (i); |
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417 | else |
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418 | { |
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419 | io_watcher &w = *iow[i]; |
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420 | short revents = w.events; |
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421 | |
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422 | if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ; |
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423 | if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE; |
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424 | |
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425 | if (revents) |
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426 | w.call (w, revents); |
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427 | } |
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428 | #endif |
130 | } |
429 | } |
131 | |
430 | else if (fds < 0 && errno != EINTR) |
132 | w->registered = false; |
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133 | } |
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134 | } |
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135 | |
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136 | inline void set_now (void) |
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137 | { |
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138 | struct timeval tv; |
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139 | |
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140 | gettimeofday (&tv, 0); |
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141 | |
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142 | NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000; |
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143 | } |
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144 | |
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145 | void io_manager::loop () |
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146 | { |
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147 | set_now (); |
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148 | |
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149 | for (;;) |
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150 | { |
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151 | while (tw[0]->at <= NOW) |
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152 | { |
431 | { |
153 | // remove the first watcher |
432 | perror ("io_manager: fatal error while waiting for I/O or time event, aborting."); |
154 | time_watcher *w = tw[0]; |
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155 | |
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156 | pop_heap (tw.begin (), tw.end (), lowest_first); |
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157 | tw.pop_back (); |
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158 | |
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159 | w->registered = false; |
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160 | |
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161 | // call it |
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162 | w->call (w->at); |
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163 | |
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164 | // re-add it if necessary |
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165 | if (w->at >= 0 && !w->registered) |
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166 | reg (w); |
433 | abort (); |
167 | } |
434 | } |
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435 | #if IOM_IDLE |
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436 | else |
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437 | for (int i = iw.size (); i--; ) |
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438 | if (!iw[i]) |
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439 | iw.erase_unordered (i); |
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440 | else |
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441 | iw[i]->call (*iw[i]); |
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442 | #endif |
168 | |
443 | |
169 | int timeout = (int) ((tw[0]->at - NOW) * 1000); |
444 | #elif IOM_TIME |
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445 | if (!to) |
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446 | break; |
170 | |
447 | |
171 | int fds = poll (&pfs[0], pfs.size (), timeout); |
448 | select (0, 0, 0, 0, &to); |
172 | |
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173 | set_now (); |
449 | set_now (); |
174 | |
450 | #else |
175 | for (unsigned int i = iow.size (); fds > 0 && i--; ) |
451 | break; |
176 | if (pfs[i].revents) |
452 | #endif |
177 | { |
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178 | --fds; |
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179 | iow[i]->call (pfs[i].revents); |
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180 | } |
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181 | } |
453 | } |
182 | } |
454 | } |
183 | |
455 | |
184 | void io_manager::idle_cb (tstamp &ts) |
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185 | { |
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186 | ts = NOW + 86400; // wake up every day, for no good reason |
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187 | } |
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188 | |
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189 | io_manager::io_manager () |
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190 | { |
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191 | set_now (); |
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192 | idle = new time_watcher (this, &io_manager::idle_cb); |
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193 | idle->start (0); |
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194 | } |
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195 | |
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196 | io_manager::~io_manager () |
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197 | { |
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198 | // |
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199 | } |
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200 | |
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