Guido van Rossum | f70e43a | 1991-02-19 12:39:46 +0000 | [diff] [blame] | 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 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 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, |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 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 |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 40 | - errno is a global variable, which makes extensions to a multi- |
| 41 | threading environment difficult; e.g., in IRIX, multi-threaded |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 42 | programs must use the function oserror() instead of looking in errno |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 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 |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 51 | built-in function calls err_set(exception), err_setval(exception, |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 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 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 58 | #include "allobjects.h" |
| 59 | |
Guido van Rossum | f22120a | 1990-12-20 23:05:40 +0000 | [diff] [blame] | 60 | #include <errno.h> |
| 61 | #ifndef errno |
| 62 | extern int errno; |
| 63 | #endif |
| 64 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 65 | #include "errcode.h" |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 66 | |
Guido van Rossum | f5401bd | 1990-11-02 17:50:28 +0000 | [diff] [blame] | 67 | extern char *strerror PROTO((int)); |
| 68 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 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 | { |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 79 | XDECREF(last_exception); |
| 80 | XINCREF(exception); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 81 | last_exception = exception; |
| 82 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 83 | XDECREF(last_exc_val); |
| 84 | XINCREF(value); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 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); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 102 | XDECREF(value); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 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 | { |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 125 | XDECREF(last_exception); |
| 126 | last_exception = NULL; |
| 127 | XDECREF(last_exc_val); |
| 128 | last_exc_val = NULL; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 129 | } |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 130 | |
| 131 | /* Convenience functions to set a type error exception and return 0 */ |
| 132 | |
| 133 | int |
| 134 | err_badarg() |
| 135 | { |
Guido van Rossum | f1ac403 | 1990-11-09 15:05:53 +0000 | [diff] [blame] | 136 | err_setstr(TypeError, "illegal argument type for built-in operation"); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | object * |
| 141 | err_nomem() |
| 142 | { |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 143 | err_set(MemoryError); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 144 | return NULL; |
| 145 | } |
| 146 | |
| 147 | object * |
| 148 | err_errno(exc) |
| 149 | object *exc; |
| 150 | { |
Guido van Rossum | 5063bab | 1991-10-20 20:14:56 +0000 | [diff] [blame] | 151 | object *v; |
| 152 | if (errno == EINTR && intrcheck()) { |
| 153 | err_set(KeyboardInterrupt); |
| 154 | return NULL; |
| 155 | } |
| 156 | v = newtupleobject(2); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 157 | if (v != NULL) { |
| 158 | settupleitem(v, 0, newintobject((long)errno)); |
| 159 | settupleitem(v, 1, newstringobject(strerror(errno))); |
| 160 | } |
| 161 | err_setval(exc, v); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 162 | XDECREF(v); |
Guido van Rossum | 7d310eb | 1990-10-14 20:00:05 +0000 | [diff] [blame] | 163 | return NULL; |
| 164 | } |
Guido van Rossum | 683a072 | 1990-10-21 22:09:12 +0000 | [diff] [blame] | 165 | |
| 166 | void |
| 167 | err_badcall() |
| 168 | { |
| 169 | err_setstr(SystemError, "bad argument to internal function"); |
| 170 | } |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 171 | |
| 172 | /* Set the error appropriate to the given input error code (see errcode.h) */ |
| 173 | |
| 174 | void |
| 175 | err_input(err) |
| 176 | int err; |
| 177 | { |
| 178 | switch (err) { |
| 179 | case E_DONE: |
| 180 | case E_OK: |
| 181 | break; |
| 182 | case E_SYNTAX: |
Guido van Rossum | b954c2c | 1991-12-16 13:05:50 +0000 | [diff] [blame] | 183 | err_setstr(SyntaxError, "invalid syntax"); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 184 | break; |
| 185 | case E_TOKEN: |
Guido van Rossum | b954c2c | 1991-12-16 13:05:50 +0000 | [diff] [blame] | 186 | err_setstr(SyntaxError, "invalid token"); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 187 | break; |
| 188 | case E_INTR: |
| 189 | err_set(KeyboardInterrupt); |
| 190 | break; |
| 191 | case E_NOMEM: |
| 192 | err_nomem(); |
| 193 | break; |
| 194 | case E_EOF: |
Guido van Rossum | 86d8e63 | 1991-12-24 13:26:15 +0000 | [diff] [blame] | 195 | err_setstr(EOFError, "unexpected EOF while parsing"); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 196 | break; |
| 197 | default: |
Guido van Rossum | b954c2c | 1991-12-16 13:05:50 +0000 | [diff] [blame] | 198 | err_setstr(SystemError, "unknown parsing error"); |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 199 | break; |
| 200 | } |
| 201 | } |