Mercurial > cpython-lru_cache-weakref
annotate Python/errors.c @ 145:853b736a6a9e legacy-trunk
Added copyright notice.
| author | Guido van Rossum <guido@python.org> |
|---|---|
| date | Tue, 19 Feb 1991 12:39:46 +0000 |
| parents | 5cb843bc87fc |
| children | 172aa2c3e734 |
| rev | line source |
|---|---|
| 145 | 1 /*********************************************************** |
| 2 Copyright 1991 by Stichting Mathematisch Centrum, Amsterdam, The | |
| 3 Netherlands. | |
| 4 | |
| 5 All Rights Reserved | |
| 6 | |
| 7 Permission to use, copy, modify, and distribute this software and its | |
| 8 documentation for any purpose and without fee is hereby granted, | |
| 9 provided that the above copyright notice appear in all copies and that | |
| 10 both that copyright notice and this permission notice appear in | |
| 11 supporting documentation, and that the names of Stichting Mathematisch | |
| 12 Centrum or CWI not be used in advertising or publicity pertaining to | |
| 13 distribution of the software without specific, written prior permission. | |
| 14 | |
| 15 STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO | |
| 16 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND | |
| 17 FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE | |
| 18 FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
| 19 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
| 20 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT | |
| 21 OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
| 22 | |
| 23 ******************************************************************/ | |
| 24 | |
| 6 | 25 /* Error handling -- see also run.c */ |
| 26 | |
| 27 /* New error handling interface. | |
| 28 | |
| 29 The following problem exists (existed): methods of built-in modules | |
| 30 are called with 'self' and 'args' arguments, but without a context | |
| 31 argument, so they have no way to raise a specific exception. | |
| 32 The same is true for the object implementations: no context argument. | |
| 33 The old convention was to set 'errno' and to return NULL. | |
| 34 The caller (usually call_function() in eval.c) detects the NULL | |
| 35 return value and then calls puterrno(ctx) to turn the errno value | |
| 36 into a true exception. Problems with this approach are: | |
| 37 - it used standard errno values to indicate Python-specific errors, | |
| 86 | 38 but this means that when such an error code is reported by a system |
| 39 call (e.g., in module posix), the user gets a confusing message | |
| 6 | 40 - errno is a global variable, which makes extensions to a multi- |
| 41 threading environment difficult; e.g., in IRIX, multi-threaded | |
| 86 | 42 programs must use the function oserror() instead of looking in errno |
| 6 | 43 - there is no portable way to add new error numbers for specic |
| 44 situations -- the value space for errno is reserved to the OS, yet | |
| 45 the way to turn module-specific errors into a module-specific | |
| 46 exception requires module-specific values for errno | |
| 47 - there is no way to add a more situation-specific message to an | |
| 48 error. | |
| 49 | |
| 50 The new interface solves all these problems. To return an error, a | |
| 86 | 51 built-in function calls err_set(exception), err_setval(exception, |
| 6 | 52 value) or err_setstr(exception, string), and returns NULL. These |
| 53 functions save the value for later use by puterrno(). To adapt this | |
| 54 scheme to a multi-threaded environment, only the implementation of | |
| 55 err_setval() has to be changed. | |
| 56 */ | |
| 57 | |
|
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58 #include "allobjects.h" |
| 6 | 59 |
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60 #include <errno.h> |
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61 #ifndef errno |
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62 extern int errno; |
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63 #endif |
| 86 | 64 |
| 65 #include "errcode.h" | |
| 6 | 66 |
|
59
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67 extern char *strerror PROTO((int)); |
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68 |
| 6 | 69 /* Last exception stored by err_setval() */ |
| 70 | |
| 71 static object *last_exception; | |
| 72 static object *last_exc_val; | |
| 73 | |
| 74 void | |
| 75 err_setval(exception, value) | |
| 76 object *exception; | |
| 77 object *value; | |
| 78 { | |
| 86 | 79 XDECREF(last_exception); |
| 80 XINCREF(exception); | |
| 6 | 81 last_exception = exception; |
| 82 | |
| 86 | 83 XDECREF(last_exc_val); |
| 84 XINCREF(value); | |
| 6 | 85 last_exc_val = value; |
| 86 } | |
| 87 | |
| 88 void | |
| 89 err_set(exception) | |
| 90 object *exception; | |
| 91 { | |
| 92 err_setval(exception, (object *)NULL); | |
| 93 } | |
| 94 | |
| 95 void | |
| 96 err_setstr(exception, string) | |
| 97 object *exception; | |
| 98 char *string; | |
| 99 { | |
| 100 object *value = newstringobject(string); | |
| 101 err_setval(exception, value); | |
| 86 | 102 XDECREF(value); |
| 6 | 103 } |
| 104 | |
| 105 int | |
| 106 err_occurred() | |
| 107 { | |
| 108 return last_exception != NULL; | |
| 109 } | |
| 110 | |
| 111 void | |
| 112 err_get(p_exc, p_val) | |
| 113 object **p_exc; | |
| 114 object **p_val; | |
| 115 { | |
| 116 *p_exc = last_exception; | |
| 117 last_exception = NULL; | |
| 118 *p_val = last_exc_val; | |
| 119 last_exc_val = NULL; | |
| 120 } | |
| 121 | |
| 122 void | |
| 123 err_clear() | |
| 124 { | |
| 86 | 125 XDECREF(last_exception); |
| 126 last_exception = NULL; | |
| 127 XDECREF(last_exc_val); | |
| 128 last_exc_val = NULL; | |
| 6 | 129 } |
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130 |
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131 /* Convenience functions to set a type error exception and return 0 */ |
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132 |
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133 int |
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134 err_badarg() |
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135 { |
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136 err_setstr(TypeError, "illegal argument type for built-in operation"); |
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137 return 0; |
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138 } |
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139 |
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140 object * |
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141 err_nomem() |
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142 { |
| 86 | 143 err_set(MemoryError); |
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144 return NULL; |
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145 } |
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146 |
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147 object * |
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148 err_errno(exc) |
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149 object *exc; |
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150 { |
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151 object *v = newtupleobject(2); |
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152 if (v != NULL) { |
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153 settupleitem(v, 0, newintobject((long)errno)); |
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154 settupleitem(v, 1, newstringobject(strerror(errno))); |
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155 } |
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156 err_setval(exc, v); |
| 86 | 157 XDECREF(v); |
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158 return NULL; |
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159 } |
| 22 | 160 |
| 161 void | |
| 162 err_badcall() | |
| 163 { | |
| 164 err_setstr(SystemError, "bad argument to internal function"); | |
| 165 } | |
| 86 | 166 |
| 167 /* Set the error appropriate to the given input error code (see errcode.h) */ | |
| 168 | |
| 169 void | |
| 170 err_input(err) | |
| 171 int err; | |
| 172 { | |
| 173 switch (err) { | |
| 174 case E_DONE: | |
| 175 case E_OK: | |
| 176 break; | |
| 177 case E_SYNTAX: | |
| 178 err_setstr(RuntimeError, "syntax error"); | |
| 179 break; | |
| 180 case E_TOKEN: | |
| 181 err_setstr(RuntimeError, "illegal token"); | |
| 182 break; | |
| 183 case E_INTR: | |
| 184 err_set(KeyboardInterrupt); | |
| 185 break; | |
| 186 case E_NOMEM: | |
| 187 err_nomem(); | |
| 188 break; | |
| 189 case E_EOF: | |
| 190 err_set(EOFError); | |
| 191 break; | |
| 192 default: | |
| 193 err_setstr(RuntimeError, "unknown input error"); | |
| 194 break; | |
| 195 } | |
| 196 } |