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1 /* |
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2 |
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3 Copyright (C) 1996, 1997 John W. Eaton |
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4 |
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5 This file is part of Octave. |
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6 |
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7 Octave is free software; you can redistribute it and/or modify it |
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8 under the terms of the GNU General Public License as published by the |
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9 Free Software Foundation; either version 2, or (at your option) any |
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10 later version. |
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11 |
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12 Octave is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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15 for more details. |
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16 |
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17 You should have received a copy of the GNU General Public License |
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18 along with Octave; see the file COPYING. If not, write to the Free |
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19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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20 |
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21 */ |
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22 |
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23 #if defined (__GNUG__) && defined (USE_PRAGMA_INTERFACE_IMPLEMENTATION) |
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24 #pragma implementation |
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25 #endif |
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26 |
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27 #ifdef HAVE_CONFIG_H |
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28 #include <config.h> |
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29 #endif |
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30 |
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31 #include "quit.h" |
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32 |
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33 #include "error.h" |
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34 #include "oct-lvalue.h" |
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35 #include "ov.h" |
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36 #include "pt-bp.h" |
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37 #include "pt-cmd.h" |
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38 #include "pt-except.h" |
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39 #include "pt-exp.h" |
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40 #include "pt-jump.h" |
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41 #include "pt-stmt.h" |
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42 #include "pt-walk.h" |
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43 #include "unwind-prot.h" |
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44 #include "variables.h" |
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45 |
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46 // Simple exception handling. |
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47 |
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48 tree_try_catch_command::~tree_try_catch_command (void) |
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49 { |
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50 delete try_code; |
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51 delete catch_code; |
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52 delete lead_comm; |
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53 delete mid_comm; |
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54 delete trail_comm; |
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55 } |
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56 |
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57 static void |
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58 do_catch_code (void *ptr) |
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59 { |
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60 if (octave_interrupt_immediately) |
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61 return; |
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62 |
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63 tree_statement_list *list = static_cast<tree_statement_list *> (ptr); |
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64 |
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65 unwind_protect::begin_frame ("do_catch_code"); |
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66 |
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67 // Set up for letting the user print any messages from errors that |
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68 // occurred in the body of the try_catch statement. |
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69 |
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70 unwind_protect_bool (buffer_error_messages); |
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71 buffer_error_messages = false; |
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72 |
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73 bind_global_error_variable (); |
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74 |
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75 unwind_protect::add (clear_global_error_variable, 0); |
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76 |
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77 if (list) |
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78 list->eval (); |
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79 |
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80 unwind_protect::run_frame ("do_catch_code"); |
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81 } |
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82 |
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83 void |
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84 tree_try_catch_command::eval (void) |
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85 { |
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86 unwind_protect::begin_frame ("tree_try_catch::eval"); |
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87 |
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88 MAYBE_DO_BREAKPOINT; |
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89 |
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90 if (catch_code) |
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91 { |
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92 unwind_protect_bool (buffer_error_messages); |
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93 buffer_error_messages = true; |
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94 } |
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95 |
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96 unwind_protect::add (do_catch_code, catch_code); |
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97 |
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98 if (try_code) |
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99 try_code->eval (); |
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100 |
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101 if (catch_code && error_state) |
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102 { |
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103 error_state = 0; |
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104 unwind_protect::run_frame ("tree_try_catch::eval"); |
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105 } |
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106 else |
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107 { |
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108 error_state = 0; |
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109 |
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110 // For clearing the do_catch_code cleanup function. |
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111 unwind_protect::discard (); |
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112 |
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113 // For restoring buffer_error_messages. |
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114 if (catch_code) |
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115 unwind_protect::run (); |
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116 |
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117 // Also clear the frame marker. |
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118 unwind_protect::discard (); |
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119 } |
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120 } |
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121 |
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122 void |
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123 tree_try_catch_command::accept (tree_walker& tw) |
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124 { |
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125 tw.visit_try_catch_command (*this); |
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126 } |
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127 |
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128 // Simple exception handling. |
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129 |
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130 tree_unwind_protect_command::~tree_unwind_protect_command (void) |
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131 { |
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132 delete unwind_protect_code; |
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133 delete cleanup_code; |
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134 delete lead_comm; |
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135 delete mid_comm; |
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136 delete trail_comm; |
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137 } |
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138 |
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139 static void |
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140 do_unwind_protect_cleanup_code (void *ptr) |
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141 { |
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142 tree_statement_list *list = static_cast<tree_statement_list *> (ptr); |
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143 |
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144 // We want to run the cleanup code without error_state being set, |
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145 // but we need to restore its value, so that any errors encountered |
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146 // in the first part of the unwind_protect are not completely |
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147 // ignored. |
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148 |
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149 unwind_protect_int (error_state); |
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150 error_state = 0; |
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151 |
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152 // Similarly, if we have seen a return or break statement, allow all |
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153 // the cleanup code to run before returning or handling the break. |
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154 // We don't have to worry about continue statements because they can |
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155 // only occur in loops. |
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156 |
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157 unwind_protect_int (tree_return_command::returning); |
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158 tree_return_command::returning = 0; |
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159 |
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160 unwind_protect_int (tree_break_command::breaking); |
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161 tree_break_command::breaking = 0; |
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162 |
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163 if (list) |
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164 list->eval (); |
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165 |
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166 // The unwind_protects are popped off the stack in the reverse of |
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167 // the order they are pushed on. |
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168 |
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169 // XXX FIXME XXX -- these statements say that if we see a break or |
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170 // return statement in the cleanup block, that we want to use the |
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171 // new value of the breaking or returning flag instead of restoring |
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172 // the previous value. Is that the right thing to do? I think so. |
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173 // Consider the case of |
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174 // |
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175 // function foo () |
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176 // unwind_protect |
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177 // stderr << "1: this should always be executed\n"; |
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178 // break; |
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179 // stderr << "1: this should never be executed\n"; |
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180 // unwind_protect_cleanup |
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181 // stderr << "2: this should always be executed\n"; |
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182 // return; |
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183 // stderr << "2: this should never be executed\n"; |
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184 // end_unwind_protect |
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185 // endfunction |
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186 // |
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187 // If we reset the value of the breaking flag, both the returning |
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188 // flag and the breaking flag will be set, and we shouldn't have |
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189 // both. So, use the most recent one. If there is no return or |
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190 // break in the cleanup block, the values should be reset to |
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191 // whatever they were when the cleanup block was entered. |
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192 |
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193 if (tree_break_command::breaking || tree_return_command::returning) |
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194 { |
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195 unwind_protect::discard (); |
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196 unwind_protect::discard (); |
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197 } |
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198 else |
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199 { |
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200 unwind_protect::run (); |
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201 unwind_protect::run (); |
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202 } |
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203 |
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204 // We don't want to ignore errors that occur in the cleanup code, so |
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205 // if an error is encountered there, leave error_state alone. |
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206 // Otherwise, set it back to what it was before. |
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207 |
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208 if (error_state) |
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209 unwind_protect::discard (); |
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210 else |
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211 unwind_protect::run (); |
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212 } |
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213 |
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214 void |
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215 tree_unwind_protect_command::eval (void) |
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216 { |
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217 unwind_protect::add (do_unwind_protect_cleanup_code, cleanup_code); |
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218 |
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219 MAYBE_DO_BREAKPOINT; |
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220 |
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221 if (unwind_protect_code) |
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222 unwind_protect_code->eval (); |
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223 |
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224 unwind_protect::run (); |
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225 } |
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226 |
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227 void |
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228 tree_unwind_protect_command::accept (tree_walker& tw) |
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229 { |
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230 tw.visit_unwind_protect_command (*this); |
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231 } |
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232 |
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233 /* |
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234 ;;; Local Variables: *** |
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235 ;;; mode: C++ *** |
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236 ;;; End: *** |
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237 */ |
