1 | // |
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2 | // "$Id$" |
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3 | // |
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4 | // Multi-threading support code for the Fast Light Tool Kit (FLTK). |
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5 | // |
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6 | // Copyright 1998-2007 by Bill Spitzak and others. |
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7 | // |
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8 | // This library is free software; you can redistribute it and/or |
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9 | // modify it under the terms of the GNU Library General Public |
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10 | // License as published by the Free Software Foundation; either |
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11 | // version 2 of the License, or (at your option) any later version. |
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12 | // |
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13 | // This library is distributed in the hope that it will be useful, |
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14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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16 | // Library General Public License for more details. |
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17 | // |
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18 | // You should have received a copy of the GNU Library General Public |
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19 | // License along with this library; if not, write to the Free Software |
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20 | // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
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21 | // USA. |
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22 | // |
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23 | // Please report all bugs and problems on the following page: |
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24 | // |
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25 | // http://www.fltk.org/str.php |
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26 | // |
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27 | |
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28 | |
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29 | #include <FL/Fl.H> |
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30 | #include <config.h> |
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31 | |
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32 | #include <stdlib.h> |
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33 | |
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34 | /* |
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35 | From Bill: |
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36 | |
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37 | I would prefer that FLTK contain the minimal amount of extra |
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38 | stuff for doing threads. There are other portable thread |
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39 | wrapper libraries out there and FLTK should not be providing |
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40 | another. This file is an attempt to make minimal additions |
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41 | and make them self-contained in this source file. |
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42 | |
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43 | From Mike: |
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44 | |
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45 | Starting with 1.1.8, we now have a callback so that you can |
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46 | process awake() messages as they come in. |
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47 | |
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48 | |
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49 | The API: |
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50 | |
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51 | Fl::lock() - recursive lock. You must call this before the |
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52 | first call to Fl::wait()/run() to initialize the thread |
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53 | system. The lock is locked all the time except when |
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54 | Fl::wait() is waiting for events. |
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55 | |
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56 | Fl::unlock() - release the recursive lock. |
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57 | |
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58 | Fl::awake(void*) - Causes Fl::wait() to return (with the lock |
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59 | locked) even if there are no events ready. |
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60 | |
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61 | Fl::awake(void (*cb)(void *), void*) - Call a function |
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62 | in the main thread from within another thread of execution. |
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63 | |
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64 | Fl::thread_message() - returns an argument sent to an |
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65 | Fl::awake() call, or returns NULL if none. WARNING: the |
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66 | current implementation only has a one-entry queue and only |
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67 | returns the most recent value! |
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68 | */ |
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69 | |
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70 | Fl_Awake_Handler *Fl::awake_ring_; |
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71 | void **Fl::awake_data_; |
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72 | int Fl::awake_ring_size_; |
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73 | int Fl::awake_ring_head_; |
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74 | int Fl::awake_ring_tail_; |
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75 | static const int AWAKE_RING_SIZE = 1024; |
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76 | |
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77 | static void lock_ring(); |
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78 | static void unlock_ring(); |
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79 | |
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80 | |
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81 | int Fl::add_awake_handler_(Fl_Awake_Handler func, void *data) |
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82 | { |
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83 | int ret = 0; |
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84 | lock_ring(); |
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85 | if (!awake_ring_) { |
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86 | awake_ring_size_ = AWAKE_RING_SIZE; |
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87 | awake_ring_ = (Fl_Awake_Handler*)malloc(awake_ring_size_*sizeof(Fl_Awake_Handler)); |
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88 | awake_data_ = (void**)malloc(awake_ring_size_*sizeof(void*)); |
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89 | } |
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90 | if (awake_ring_head_==awake_ring_tail_-1 || awake_ring_head_+1==awake_ring_tail_) { |
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91 | // ring is full. Return -1 as an error indicator. |
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92 | ret = -1; |
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93 | } else { |
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94 | awake_ring_[awake_ring_head_] = func; |
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95 | awake_data_[awake_ring_head_] = data; |
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96 | ++awake_ring_head_; |
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97 | if (awake_ring_head_ == awake_ring_size_) |
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98 | awake_ring_head_ = 0; |
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99 | } |
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100 | unlock_ring(); |
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101 | return ret; |
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102 | } |
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103 | |
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104 | int Fl::get_awake_handler_(Fl_Awake_Handler &func, void *&data) |
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105 | { |
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106 | int ret = 0; |
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107 | lock_ring(); |
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108 | if (!awake_ring_ || awake_ring_head_ == awake_ring_tail_) { |
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109 | ret = -1; |
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110 | } else { |
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111 | func = awake_ring_[awake_ring_tail_]; |
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112 | data = awake_data_[awake_ring_tail_]; |
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113 | ++awake_ring_tail_; |
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114 | if (awake_ring_tail_ == awake_ring_size_) |
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115 | awake_ring_tail_ = 0; |
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116 | } |
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117 | unlock_ring(); |
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118 | return ret; |
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119 | } |
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120 | |
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121 | // |
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122 | // 'Fl::awake()' - Let the main thread know an update is pending |
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123 | // and have it cal a specific function |
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124 | // |
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125 | int Fl::awake(Fl_Awake_Handler func, void *data) { |
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126 | int ret = add_awake_handler_(func, data); |
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127 | Fl::awake(); |
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128 | return ret; |
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129 | } |
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130 | |
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131 | //////////////////////////////////////////////////////////////// |
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132 | // Windows threading... |
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133 | #ifdef WIN32 |
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134 | # include <windows.h> |
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135 | # include <process.h> |
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136 | # include <FL/x.H> |
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137 | |
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138 | // These pointers are in Fl_win32.cxx: |
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139 | extern void (*fl_lock_function)(); |
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140 | extern void (*fl_unlock_function)(); |
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141 | |
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142 | // The main thread's ID |
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143 | static DWORD main_thread; |
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144 | |
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145 | // Microsoft's version of a MUTEX... |
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146 | CRITICAL_SECTION cs; |
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147 | CRITICAL_SECTION *cs_ring; |
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148 | |
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149 | void unlock_ring() { |
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150 | LeaveCriticalSection(cs_ring); |
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151 | } |
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152 | |
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153 | void lock_ring() { |
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154 | if (!cs_ring) { |
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155 | cs_ring = (CRITICAL_SECTION*)malloc(sizeof(CRITICAL_SECTION)); |
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156 | InitializeCriticalSection(cs_ring); |
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157 | } |
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158 | EnterCriticalSection(cs_ring); |
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159 | } |
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160 | |
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161 | // |
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162 | // 'unlock_function()' - Release the lock. |
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163 | // |
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164 | |
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165 | static void unlock_function() { |
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166 | LeaveCriticalSection(&cs); |
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167 | } |
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168 | |
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169 | // |
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170 | // 'lock_function()' - Get the lock. |
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171 | // |
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172 | |
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173 | static void lock_function() { |
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174 | EnterCriticalSection(&cs); |
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175 | } |
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176 | |
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177 | // |
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178 | // 'Fl::lock()' - Lock access to FLTK data structures... |
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179 | // |
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180 | |
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181 | void Fl::lock() { |
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182 | if (!main_thread) InitializeCriticalSection(&cs); |
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183 | |
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184 | lock_function(); |
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185 | |
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186 | if (!main_thread) { |
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187 | fl_lock_function = lock_function; |
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188 | fl_unlock_function = unlock_function; |
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189 | main_thread = GetCurrentThreadId(); |
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190 | } |
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191 | } |
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192 | |
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193 | // |
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194 | // 'Fl::unlock()' - Unlock access to FLTK data structures... |
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195 | // |
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196 | |
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197 | void Fl::unlock() { |
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198 | unlock_function(); |
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199 | } |
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200 | |
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201 | |
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202 | // |
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203 | // 'Fl::awake()' - Let the main thread know an update is pending. |
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204 | // |
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205 | // When called from a thread, it causes FLTK to awake from Fl::wait()... |
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206 | // |
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207 | |
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208 | void Fl::awake(void* msg) { |
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209 | PostThreadMessage( main_thread, fl_wake_msg, (WPARAM)msg, 0); |
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210 | } |
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211 | |
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212 | //////////////////////////////////////////////////////////////// |
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213 | // POSIX threading... |
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214 | #elif HAVE_PTHREAD |
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215 | # include <unistd.h> |
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216 | # include <fcntl.h> |
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217 | # include <pthread.h> |
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218 | |
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219 | // Pipe for thread messaging via Fl::awake()... |
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220 | static int thread_filedes[2]; |
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221 | |
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222 | // Mutex and state information for Fl::lock() and Fl::unlock()... |
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223 | static pthread_mutex_t fltk_mutex; |
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224 | static pthread_t owner; |
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225 | static int counter; |
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226 | |
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227 | static void lock_function_init_std() { |
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228 | pthread_mutex_init(&fltk_mutex, NULL); |
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229 | } |
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230 | |
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231 | static void lock_function_std() { |
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232 | if (!counter || owner != pthread_self()) { |
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233 | pthread_mutex_lock(&fltk_mutex); |
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234 | owner = pthread_self(); |
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235 | } |
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236 | counter++; |
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237 | } |
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238 | |
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239 | static void unlock_function_std() { |
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240 | if (!--counter) pthread_mutex_unlock(&fltk_mutex); |
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241 | } |
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242 | |
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243 | # ifdef PTHREAD_MUTEX_RECURSIVE |
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244 | static bool lock_function_init_rec() { |
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245 | pthread_mutexattr_t attrib; |
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246 | pthread_mutexattr_init(&attrib); |
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247 | if (pthread_mutexattr_settype(&attrib, PTHREAD_MUTEX_RECURSIVE)) { |
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248 | pthread_mutexattr_destroy(&attrib); |
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249 | return true; |
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250 | } |
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251 | |
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252 | pthread_mutex_init(&fltk_mutex, &attrib); |
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253 | return false; |
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254 | } |
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255 | |
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256 | static void lock_function_rec() { |
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257 | pthread_mutex_lock(&fltk_mutex); |
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258 | } |
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259 | |
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260 | static void unlock_function_rec() { |
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261 | pthread_mutex_unlock(&fltk_mutex); |
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262 | } |
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263 | # endif // PTHREAD_MUTEX_RECURSIVE |
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264 | |
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265 | void Fl::awake(void* msg) { |
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266 | write(thread_filedes[1], &msg, sizeof(void*)); |
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267 | } |
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268 | |
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269 | static void* thread_message_; |
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270 | void* Fl::thread_message() { |
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271 | void* r = thread_message_; |
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272 | thread_message_ = 0; |
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273 | return r; |
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274 | } |
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275 | |
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276 | static void thread_awake_cb(int fd, void*) { |
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277 | read(fd, &thread_message_, sizeof(void*)); |
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278 | Fl_Awake_Handler func; |
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279 | void *data; |
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280 | while (Fl::get_awake_handler_(func, data)==0) { |
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281 | (*func)(data); |
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282 | } |
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283 | } |
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284 | |
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285 | // These pointers are in Fl_x.cxx: |
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286 | extern void (*fl_lock_function)(); |
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287 | extern void (*fl_unlock_function)(); |
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288 | |
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289 | void Fl::lock() { |
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290 | if (!thread_filedes[1]) { |
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291 | // Initialize thread communication pipe to let threads awake FLTK |
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292 | // from Fl::wait() |
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293 | pipe(thread_filedes); |
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294 | |
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295 | // Make the write side of the pipe non-blocking to avoid deadlock |
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296 | // conditions (STR #1537) |
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297 | fcntl(thread_filedes[1], F_SETFL, |
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298 | fcntl(thread_filedes[1], F_GETFL) | O_NONBLOCK); |
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299 | |
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300 | // Monitor the read side of the pipe so that messages sent via |
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301 | // Fl::awake() from a thread will "wake up" the main thread in |
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302 | // Fl::wait(). |
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303 | Fl::add_fd(thread_filedes[0], FL_READ, thread_awake_cb); |
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304 | |
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305 | // Set lock/unlock functions for this system, using a system-supplied |
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306 | // recursive mutex if supported... |
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307 | # ifdef PTHREAD_MUTEX_RECURSIVE |
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308 | if (!lock_function_init_rec()) { |
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309 | fl_lock_function = lock_function_rec; |
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310 | fl_unlock_function = unlock_function_rec; |
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311 | } else { |
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312 | # endif // PTHREAD_MUTEX_RECURSIVE |
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313 | lock_function_init_std(); |
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314 | fl_lock_function = lock_function_std; |
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315 | fl_unlock_function = unlock_function_std; |
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316 | # ifdef PTHREAD_MUTEX_RECURSIVE |
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317 | } |
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318 | # endif // PTHREAD_MUTEX_RECURSIVE |
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319 | } |
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320 | |
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321 | fl_lock_function(); |
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322 | } |
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323 | |
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324 | void Fl::unlock() { |
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325 | fl_unlock_function(); |
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326 | } |
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327 | |
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328 | // Mutex code for the awake ring buffer |
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329 | static pthread_mutex_t *ring_mutex; |
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330 | |
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331 | void unlock_ring() { |
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332 | pthread_mutex_unlock(ring_mutex); |
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333 | } |
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334 | |
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335 | void lock_ring() { |
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336 | if (!ring_mutex) { |
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337 | ring_mutex = (pthread_mutex_t*)malloc(sizeof(pthread_mutex_t)); |
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338 | pthread_mutex_init(ring_mutex, NULL); |
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339 | } |
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340 | pthread_mutex_lock(ring_mutex); |
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341 | } |
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342 | |
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343 | #else |
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344 | |
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345 | void unlock_ring() { |
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346 | } |
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347 | |
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348 | void lock_ring() { |
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349 | } |
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350 | |
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351 | void Fl::awake(void*) { |
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352 | } |
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353 | |
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354 | #endif // WIN32 |
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355 | |
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356 | // |
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357 | // End of "$Id$". |
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358 | // |
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