Guido van Rossum | feee4b9 | 2000-03-10 22:57:27 +0000 | [diff] [blame] | 1 | /* ------------------------------------------------------------------------ |
| 2 | |
| 3 | Python Codec Registry and support functions |
| 4 | |
| 5 | Written by Marc-Andre Lemburg (mal@lemburg.com). |
| 6 | |
| 7 | (c) Copyright CNRI, All Rights Reserved. NO WARRANTY. |
| 8 | |
| 9 | ------------------------------------------------------------------------ */ |
| 10 | |
| 11 | #include "Python.h" |
| 12 | #include <ctype.h> |
| 13 | |
| 14 | /* --- Globals ------------------------------------------------------------ */ |
| 15 | |
| 16 | static PyObject *_PyCodec_SearchPath; |
| 17 | static PyObject *_PyCodec_SearchCache; |
| 18 | |
| 19 | /* Flag used for lazy import of the standard encodings package */ |
| 20 | static int import_encodings_called = 0; |
| 21 | |
| 22 | /* --- Codec Registry ----------------------------------------------------- */ |
| 23 | |
| 24 | /* Import the standard encodings package which will register the first |
| 25 | codec search function. |
| 26 | |
| 27 | This is done in a lazy way so that the Unicode implementation does |
| 28 | not downgrade startup time of scripts not needing it. |
| 29 | |
| 30 | Errors are silently ignored by this function. Only one try is made. |
| 31 | |
| 32 | */ |
| 33 | |
| 34 | static |
| 35 | void import_encodings() |
| 36 | { |
| 37 | PyObject *mod; |
| 38 | |
| 39 | import_encodings_called = 1; |
| 40 | mod = PyImport_ImportModule("encodings"); |
| 41 | if (mod == NULL) { |
| 42 | PyErr_Clear(); |
| 43 | return; |
| 44 | } |
| 45 | Py_DECREF(mod); |
| 46 | } |
| 47 | |
| 48 | /* Register a new codec search function. |
| 49 | |
| 50 | The search_function's refcount is incremented by this function. */ |
| 51 | |
| 52 | int PyCodec_Register(PyObject *search_function) |
| 53 | { |
| 54 | if (!import_encodings_called) |
| 55 | import_encodings(); |
| 56 | if (search_function == NULL) { |
| 57 | PyErr_BadArgument(); |
| 58 | return -1; |
| 59 | } |
| 60 | if (!PyCallable_Check(search_function)) { |
| 61 | PyErr_SetString(PyExc_TypeError, |
| 62 | "argument must be callable"); |
| 63 | return -1; |
| 64 | } |
| 65 | return PyList_Append(_PyCodec_SearchPath, search_function); |
| 66 | } |
| 67 | |
| 68 | static |
| 69 | PyObject *lowercasestring(const char *string) |
| 70 | { |
| 71 | register int i; |
| 72 | int len = strlen(string); |
| 73 | char *p; |
| 74 | PyObject *v; |
| 75 | |
| 76 | v = PyString_FromStringAndSize(NULL, len); |
| 77 | if (v == NULL) |
| 78 | return NULL; |
| 79 | p = PyString_AS_STRING(v); |
| 80 | for (i = 0; i < len; i++) |
| 81 | p[i] = tolower(string[i]); |
| 82 | return v; |
| 83 | } |
| 84 | |
| 85 | /* Lookup the given encoding and return a tuple providing the codec |
| 86 | facilities. |
| 87 | |
| 88 | The encoding string is looked up converted to all lower-case |
| 89 | characters. This makes encodings looked up through this mechanism |
| 90 | effectively case-insensitive. |
| 91 | |
| 92 | If no codec is found, a KeyError is set and NULL returned. */ |
| 93 | |
| 94 | PyObject *_PyCodec_Lookup(const char *encoding) |
| 95 | { |
| 96 | PyObject *result, *args = NULL, *v; |
| 97 | int i, len; |
| 98 | |
| 99 | if (!import_encodings_called) |
| 100 | import_encodings(); |
| 101 | |
| 102 | /* Convert the encoding to a lower-cased Python string */ |
| 103 | v = lowercasestring(encoding); |
| 104 | if (v == NULL) |
| 105 | goto onError; |
| 106 | PyString_InternInPlace(&v); |
| 107 | |
| 108 | /* First, try to lookup the name in the registry dictionary */ |
| 109 | result = PyDict_GetItem(_PyCodec_SearchCache, v); |
| 110 | if (result != NULL) { |
| 111 | Py_INCREF(result); |
| 112 | return result; |
| 113 | } |
| 114 | |
| 115 | /* Next, scan the search functions in order of registration */ |
| 116 | len = PyList_Size(_PyCodec_SearchPath); |
| 117 | if (len < 0) |
| 118 | goto onError; |
| 119 | |
| 120 | args = PyTuple_New(1); |
| 121 | if (args == NULL) |
| 122 | goto onError; |
| 123 | PyTuple_SET_ITEM(args,0,v); |
| 124 | |
| 125 | for (i = 0; i < len; i++) { |
| 126 | PyObject *func; |
| 127 | |
| 128 | func = PyList_GetItem(_PyCodec_SearchPath, i); |
| 129 | if (func == NULL) |
| 130 | goto onError; |
| 131 | result = PyEval_CallObject(func,args); |
| 132 | if (result == NULL) |
| 133 | goto onError; |
| 134 | if (result == Py_None) { |
| 135 | Py_DECREF(result); |
| 136 | continue; |
| 137 | } |
| 138 | if (!PyTuple_Check(result) || PyTuple_GET_SIZE(result) != 4) { |
| 139 | PyErr_SetString(PyExc_TypeError, |
| 140 | "codec search functions must return 4-tuples"); |
| 141 | Py_DECREF(result); |
| 142 | goto onError; |
| 143 | } |
| 144 | break; |
| 145 | } |
| 146 | if (i == len) { |
| 147 | /* XXX Perhaps we should cache misses too ? */ |
| 148 | PyErr_SetString(PyExc_LookupError, |
| 149 | "unkown encoding"); |
| 150 | goto onError; |
| 151 | } |
| 152 | |
| 153 | /* Cache and return the result */ |
| 154 | PyDict_SetItem(_PyCodec_SearchCache, v, result); |
| 155 | Py_DECREF(args); |
| 156 | return result; |
| 157 | |
| 158 | onError: |
| 159 | Py_XDECREF(args); |
| 160 | return NULL; |
| 161 | } |
| 162 | |
| 163 | static |
| 164 | PyObject *args_tuple(PyObject *object, |
| 165 | const char *errors) |
| 166 | { |
| 167 | PyObject *args; |
| 168 | |
| 169 | args = PyTuple_New(1 + (errors != NULL)); |
| 170 | if (args == NULL) |
| 171 | return NULL; |
| 172 | Py_INCREF(object); |
| 173 | PyTuple_SET_ITEM(args,0,object); |
| 174 | if (errors) { |
| 175 | PyObject *v; |
| 176 | |
| 177 | v = PyString_FromString(errors); |
| 178 | if (v == NULL) { |
| 179 | Py_DECREF(args); |
| 180 | return NULL; |
| 181 | } |
| 182 | PyTuple_SET_ITEM(args, 1, v); |
| 183 | } |
| 184 | return args; |
| 185 | } |
| 186 | |
| 187 | /* Build a codec by calling factory(stream[,errors]) or just |
| 188 | factory(errors) depending on whether the given parameters are |
| 189 | non-NULL. */ |
| 190 | |
| 191 | static |
| 192 | PyObject *build_stream_codec(PyObject *factory, |
| 193 | PyObject *stream, |
| 194 | const char *errors) |
| 195 | { |
| 196 | PyObject *args, *codec; |
| 197 | |
| 198 | args = args_tuple(stream, errors); |
| 199 | if (args == NULL) |
| 200 | return NULL; |
| 201 | |
| 202 | codec = PyEval_CallObject(factory, args); |
| 203 | Py_DECREF(args); |
| 204 | return codec; |
| 205 | } |
| 206 | |
| 207 | /* Convenience APIs to query the Codec registry. |
| 208 | |
| 209 | All APIs return a codec object with incremented refcount. |
| 210 | |
| 211 | */ |
| 212 | |
| 213 | PyObject *PyCodec_Encoder(const char *encoding) |
| 214 | { |
| 215 | PyObject *codecs; |
| 216 | PyObject *v; |
| 217 | |
| 218 | codecs = _PyCodec_Lookup(encoding); |
| 219 | if (codecs == NULL) |
| 220 | goto onError; |
| 221 | v = PyTuple_GET_ITEM(codecs,0); |
| 222 | Py_INCREF(v); |
| 223 | return v; |
| 224 | |
| 225 | onError: |
| 226 | return NULL; |
| 227 | } |
| 228 | |
| 229 | PyObject *PyCodec_Decoder(const char *encoding) |
| 230 | { |
| 231 | PyObject *codecs; |
| 232 | PyObject *v; |
| 233 | |
| 234 | codecs = _PyCodec_Lookup(encoding); |
| 235 | if (codecs == NULL) |
| 236 | goto onError; |
| 237 | v = PyTuple_GET_ITEM(codecs,1); |
| 238 | Py_INCREF(v); |
| 239 | return v; |
| 240 | |
| 241 | onError: |
| 242 | return NULL; |
| 243 | } |
| 244 | |
| 245 | PyObject *PyCodec_StreamReader(const char *encoding, |
| 246 | PyObject *stream, |
| 247 | const char *errors) |
| 248 | { |
| 249 | PyObject *codecs; |
| 250 | |
| 251 | codecs = _PyCodec_Lookup(encoding); |
| 252 | if (codecs == NULL) |
| 253 | goto onError; |
| 254 | return build_stream_codec(PyTuple_GET_ITEM(codecs,2),stream,errors); |
| 255 | |
| 256 | onError: |
| 257 | return NULL; |
| 258 | } |
| 259 | |
| 260 | PyObject *PyCodec_StreamWriter(const char *encoding, |
| 261 | PyObject *stream, |
| 262 | const char *errors) |
| 263 | { |
| 264 | PyObject *codecs; |
| 265 | |
| 266 | codecs = _PyCodec_Lookup(encoding); |
| 267 | if (codecs == NULL) |
| 268 | goto onError; |
| 269 | return build_stream_codec(PyTuple_GET_ITEM(codecs,3),stream,errors); |
| 270 | |
| 271 | onError: |
| 272 | return NULL; |
| 273 | } |
| 274 | |
| 275 | /* Encode an object (e.g. an Unicode object) using the given encoding |
| 276 | and return the resulting encoded object (usually a Python string). |
| 277 | |
| 278 | errors is passed to the encoder factory as argument if non-NULL. */ |
| 279 | |
| 280 | PyObject *PyCodec_Encode(PyObject *object, |
| 281 | const char *encoding, |
| 282 | const char *errors) |
| 283 | { |
| 284 | PyObject *encoder = NULL; |
| 285 | PyObject *args = NULL, *result; |
| 286 | PyObject *v; |
| 287 | |
| 288 | encoder = PyCodec_Encoder(encoding); |
| 289 | if (encoder == NULL) |
| 290 | goto onError; |
| 291 | |
| 292 | args = args_tuple(object, errors); |
| 293 | if (args == NULL) |
| 294 | goto onError; |
| 295 | |
| 296 | result = PyEval_CallObject(encoder,args); |
| 297 | if (result == NULL) |
| 298 | goto onError; |
| 299 | |
| 300 | if (!PyTuple_Check(result) || |
| 301 | PyTuple_GET_SIZE(result) != 2) { |
| 302 | PyErr_SetString(PyExc_TypeError, |
| 303 | "encoder must return a tuple (object,integer)"); |
| 304 | goto onError; |
| 305 | } |
| 306 | v = PyTuple_GET_ITEM(result,0); |
| 307 | Py_INCREF(v); |
| 308 | /* We don't check or use the second (integer) entry. */ |
| 309 | |
| 310 | Py_DECREF(args); |
| 311 | Py_DECREF(encoder); |
| 312 | Py_DECREF(result); |
| 313 | return v; |
| 314 | |
| 315 | onError: |
| 316 | Py_XDECREF(args); |
| 317 | Py_XDECREF(encoder); |
| 318 | return NULL; |
| 319 | } |
| 320 | |
| 321 | /* Decode an object (usually a Python string) using the given encoding |
| 322 | and return an equivalent object (e.g. an Unicode object). |
| 323 | |
| 324 | errors is passed to the decoder factory as argument if non-NULL. */ |
| 325 | |
| 326 | PyObject *PyCodec_Decode(PyObject *object, |
| 327 | const char *encoding, |
| 328 | const char *errors) |
| 329 | { |
| 330 | PyObject *decoder = NULL; |
| 331 | PyObject *args = NULL, *result = NULL; |
| 332 | PyObject *v; |
| 333 | |
| 334 | decoder = PyCodec_Decoder(encoding); |
| 335 | if (decoder == NULL) |
| 336 | goto onError; |
| 337 | |
| 338 | args = args_tuple(object, errors); |
| 339 | if (args == NULL) |
| 340 | goto onError; |
| 341 | |
| 342 | result = PyEval_CallObject(decoder,args); |
| 343 | if (result == NULL) |
| 344 | goto onError; |
| 345 | if (!PyTuple_Check(result) || |
| 346 | PyTuple_GET_SIZE(result) != 2) { |
| 347 | PyErr_SetString(PyExc_TypeError, |
| 348 | "decoder must return a tuple (object,integer)"); |
| 349 | goto onError; |
| 350 | } |
| 351 | v = PyTuple_GET_ITEM(result,0); |
| 352 | Py_INCREF(v); |
| 353 | /* We don't check or use the second (integer) entry. */ |
| 354 | |
| 355 | Py_DECREF(args); |
| 356 | Py_DECREF(decoder); |
| 357 | Py_DECREF(result); |
| 358 | return v; |
| 359 | |
| 360 | onError: |
| 361 | Py_XDECREF(args); |
| 362 | Py_XDECREF(decoder); |
| 363 | Py_XDECREF(result); |
| 364 | return NULL; |
| 365 | } |
| 366 | |
| 367 | void _PyCodecRegistry_Init() |
| 368 | { |
| 369 | if (_PyCodec_SearchPath == NULL) |
| 370 | _PyCodec_SearchPath = PyList_New(0); |
| 371 | if (_PyCodec_SearchCache == NULL) |
| 372 | _PyCodec_SearchCache = PyDict_New(); |
| 373 | if (_PyCodec_SearchPath == NULL || |
| 374 | _PyCodec_SearchCache == NULL) |
| 375 | Py_FatalError("can't intialize codec registry"); |
| 376 | } |
| 377 | |
| 378 | void _PyCodecRegistry_Fini() |
| 379 | { |
| 380 | Py_XDECREF(_PyCodec_SearchPath); |
| 381 | Py_XDECREF(_PyCodec_SearchCache); |
| 382 | } |