gdb/python/python-value.c

   1 /* Python interface to values.
   2
   3    Copyright (C) 2008, 2009 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdb_assert.h"
  22 #include "charset.h"
  23 #include "value.h"
  24 #include "exceptions.h"
  25 #include "language.h"
  26 #include "dfp.h"
  27 #include "valprint.h"
  28
  29 /* List of all values which are currently exposed to Python. It is
  30    maintained so that when an objfile is discarded, preserve_values
  31    can copy the values' types if needed.  This is declared
  32    unconditionally to reduce the number of uses of HAVE_PYTHON in the
  33    generic code.  */
  34 /* This variable is unnecessarily initialized to NULL in order to
  35    work around a linker bug on MacOS.  */
  36 struct value *values_in_python = NULL;
  37
  38 #ifdef HAVE_PYTHON
  39
  40 #include "python-internal.h"
  41
  42 /* Even though Python scalar types directly map to host types, we use
  43    target types here to remain consistent with the the values system in
  44    GDB (which uses target arithmetic).  */
  45
  46 /* Python's integer type corresponds to C's long type.  */
  47 #define builtin_type_pyint builtin_type (current_gdbarch)->builtin_long
  48
  49 /* Python's float type corresponds to C's double type.  */
  50 #define builtin_type_pyfloat builtin_type (current_gdbarch)->builtin_double
  51
  52 /* Python's long type corresponds to C's long long type.  */
  53 #define builtin_type_pylong builtin_type (current_gdbarch)->builtin_long_long
  54
  55 #define builtin_type_pybool \
  56   language_bool_type (current_language, current_gdbarch)
  57
  58 typedef struct {
  59   PyObject_HEAD
  60   struct value *value;
  61   PyObject *address;
  62   PyObject *type;
  63 } value_object;
  64
  65 /* Called by the Python interpreter when deallocating a value object.  */
  66 static void
  67 valpy_dealloc (PyObject *obj)
  68 {
  69   value_object *self = (value_object *) obj;
  70
  71   value_remove_from_list (&values_in_python, self->value);
  72
  73   value_free (self->value);
  74
  75   if (self->address)
  76     /* Use braces to appease gcc warning.  *sigh*  */
  77     {
  78       Py_DECREF (self->address);
  79     }
  80
  81   if (self->type)
  82     {
  83       Py_DECREF (self->type);
  84     }
  85
  86   self->ob_type->tp_free (self);
  87 }
  88
  89 /* Called when a new gdb.Value object needs to be allocated.  */
  90 static PyObject *
  91 valpy_new (PyTypeObject *subtype, PyObject *args, PyObject *keywords)
  92 {
  93   struct value *value = NULL;   /* Initialize to appease gcc warning.  */
  94   value_object *value_obj;
  95
  96   if (PyTuple_Size (args) != 1)
  97     {
  98       PyErr_SetString (PyExc_TypeError, _("Value object creation takes only "
  99                                           "1 argument"));
 100       return NULL;
 101     }
 102
 103   value_obj = (value_object *) subtype->tp_alloc (subtype, 1);
 104   if (value_obj == NULL)
 105     {
 106       PyErr_SetString (PyExc_MemoryError, _("Could not allocate memory to "
 107                                             "create Value object."));
 108       return NULL;
 109     }
 110
 111   value = convert_value_from_python (PyTuple_GetItem (args, 0));
 112   if (value == NULL)
 113     {
 114       subtype->tp_free (value_obj);
 115       return NULL;
 116     }
 117
 118   value_obj->value = value;
 119   value_obj->address = NULL;
 120   value_obj->type = NULL;
 121   release_value (value);
 122   value_prepend_to_list (&values_in_python, value);
 123
 124   return (PyObject *) value_obj;
 125 }
 126
 127 /* Given a value of a pointer type, apply the C unary * operator to it.  */
 128 static PyObject *
 129 valpy_dereference (PyObject *self, PyObject *args)
 130 {
 131   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 132   volatile struct gdb_exception except;
 133
 134   TRY_CATCH (except, RETURN_MASK_ALL)
 135     {
 136       res_val = value_ind (((value_object *) self)->value);
 137     }
 138   GDB_PY_HANDLE_EXCEPTION (except);
 139
 140   return value_to_value_object (res_val);
 141 }
 142
 143 /* Return "&value".  */
 144 static PyObject *
 145 valpy_get_address (PyObject *self, void *closure)
 146 {
 147   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 148   value_object *val_obj = (value_object *) self;
 149   volatile struct gdb_exception except;
 150
 151   if (!val_obj->address)
 152     {
 153       TRY_CATCH (except, RETURN_MASK_ALL)
 154         {
 155           res_val = value_addr (val_obj->value);
 156         }
 157       if (except.reason < 0)
 158         {
 159           val_obj->address = Py_None;
 160           Py_INCREF (Py_None);
 161         }
 162       else
 163         val_obj->address = value_to_value_object (res_val);
 164     }
 165
 166   Py_INCREF (val_obj->address);
 167
 168   return val_obj->address;
 169 }
 170
 171 /* Return type of the value.  */
 172 static PyObject *
 173 valpy_get_type (PyObject *self, void *closure)
 174 {
 175   value_object *obj = (value_object *) self;
 176   if (!obj->type)
 177     {
 178       obj->type = type_to_type_object (value_type (obj->value));
 179       if (!obj->type)
 180         {
 181           obj->type = Py_None;
 182           Py_INCREF (obj->type);
 183         }
 184     }
 185   Py_INCREF (obj->type);
 186   return obj->type;
 187 }
 188
 189 /* Implementation of gdb.Value.string ([encoding] [, errors]) -> string
 190    Return Unicode string with value contents.  If ENCODING is not given,
 191    the string is assumed to be encoded in the target's charset.  */
 192 static PyObject *
 193 valpy_string (PyObject *self, PyObject *args, PyObject *kw)
 194 {
 195   int length, ret = 0;
 196   gdb_byte *buffer;
 197   struct value *value = ((value_object *) self)->value;
 198   volatile struct gdb_exception except;
 199   PyObject *unicode;
 200   const char *encoding = NULL;
 201   const char *errors = NULL;
 202   const char *user_encoding = NULL;
 203   const char *la_encoding = NULL;
 204   static char *keywords[] = { "encoding", "errors" };
 205
 206   if (!PyArg_ParseTupleAndKeywords (args, kw, "|ss", keywords,
 207                                     &user_encoding, &errors))
 208     return NULL;
 209
 210   TRY_CATCH (except, RETURN_MASK_ALL)
 211     {
 212       LA_GET_STRING (value, &buffer, &length, &la_encoding);
 213     }
 214   GDB_PY_HANDLE_EXCEPTION (except);
 215
 216   encoding = (user_encoding && *user_encoding) ? user_encoding : la_encoding;
 217   unicode = PyUnicode_Decode (buffer, length, encoding, errors);
 218   xfree (buffer);
 219
 220   return unicode;
 221 }
 222
 223 /* Cast a value to a given type.  */
 224 static PyObject *
 225 valpy_cast (PyObject *self, PyObject *args)
 226 {
 227   PyObject *type_obj;
 228   struct type *type;
 229   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 230   volatile struct gdb_exception except;
 231
 232   if (! PyArg_ParseTuple (args, "O", &type_obj))
 233     return NULL;
 234
 235   type = type_object_to_type (type_obj);
 236   if (! type)
 237     {
 238       PyErr_SetString (PyExc_RuntimeError, "argument must be a Type");
 239       return NULL;
 240     }
 241
 242   TRY_CATCH (except, RETURN_MASK_ALL)
 243     {
 244       res_val = value_cast (type, ((value_object *) self)->value);
 245     }
 246   GDB_PY_HANDLE_EXCEPTION (except);
 247
 248   return value_to_value_object (res_val);
 249 }
 250
 251 static Py_ssize_t
 252 valpy_length (PyObject *self)
 253 {
 254   /* We don't support getting the number of elements in a struct / class.  */
 255   PyErr_SetString (PyExc_NotImplementedError,
 256                    "Invalid operation on gdb.Value.");
 257   return -1;
 258 }
 259
 260 /* Given string name of an element inside structure, return its value
 261    object.  */
 262 static PyObject *
 263 valpy_getitem (PyObject *self, PyObject *key)
 264 {
 265   value_object *self_value = (value_object *) self;
 266   char *field = NULL;
 267   struct value *idx = NULL;
 268   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 269   volatile struct gdb_exception except;
 270
 271   if (gdbpy_is_string (key))
 272     {
 273       field = python_string_to_host_string (key);
 274       if (field == NULL)
 275         return NULL;
 276     }
 277
 278   TRY_CATCH (except, RETURN_MASK_ALL)
 279     {
 280       struct value *tmp = self_value->value;
 281
 282       if (field)
 283         res_val = value_struct_elt (&tmp, NULL, field, 0, NULL);
 284       else
 285         {
 286           /* Assume we are attempting an array access, and let the
 287              value code throw an exception if the index has an invalid
 288              type.  */
 289           struct value *idx = convert_value_from_python (key);
 290           if (idx == NULL)
 291             return NULL;
 292
 293           res_val = value_subscript (tmp, idx);
 294         }
 295     }
 296   if (field)
 297     xfree (field);
 298   GDB_PY_HANDLE_EXCEPTION (except);
 299
 300   return value_to_value_object (res_val);
 301 }
 302
 303 static int
 304 valpy_setitem (PyObject *self, PyObject *key, PyObject *value)
 305 {
 306   PyErr_Format (PyExc_NotImplementedError,
 307                 _("Setting of struct elements is not currently supported."));
 308   return -1;
 309 }
 310
 311 /* Called by the Python interpreter to obtain string representation
 312    of the object.  */
 313 static PyObject *
 314 valpy_str (PyObject *self)
 315 {
 316   char *s = NULL;
 317   long dummy;
 318   struct ui_file *stb;
 319   struct cleanup *old_chain;
 320   PyObject *result;
 321   struct value_print_options opts;
 322   volatile struct gdb_exception except;
 323
 324   get_user_print_options (&opts);
 325   opts.deref_ref = 0;
 326
 327   stb = mem_fileopen ();
 328   old_chain = make_cleanup_ui_file_delete (stb);
 329
 330   TRY_CATCH (except, RETURN_MASK_ALL)
 331     {
 332       common_val_print (((value_object *) self)->value, stb, 0,
 333                         &opts, current_language);
 334       s = ui_file_xstrdup (stb, &dummy);
 335     }
 336   GDB_PY_HANDLE_EXCEPTION (except);
 337
 338   do_cleanups (old_chain);
 339
 340   result = PyUnicode_Decode (s, strlen (s), host_charset (), NULL);
 341   xfree (s);
 342
 343   return result;
 344 }
 345
 346 /* Implements gdb.Value.is_optimized_out.  */
 347 static PyObject *
 348 valpy_get_is_optimized_out (PyObject *self, void *closure)
 349 {
 350   struct value *value = ((value_object *) self)->value;
 351
 352   if (value_optimized_out (value))
 353     Py_RETURN_TRUE;
 354
 355   Py_RETURN_FALSE;
 356 }
 357
 358 enum valpy_opcode
 359 {
 360   VALPY_ADD,
 361   VALPY_SUB,
 362   VALPY_MUL,
 363   VALPY_DIV,
 364   VALPY_REM,
 365   VALPY_POW,
 366   VALPY_LSH,
 367   VALPY_RSH,
 368   VALPY_BITAND,
 369   VALPY_BITOR,
 370   VALPY_BITXOR
 371 };
 372
 373 /* If TYPE is a reference, return the target; otherwise return TYPE.  */
 374 #define STRIP_REFERENCE(TYPE) \
 375   ((TYPE_CODE (TYPE) == TYPE_CODE_REF) ? (TYPE_TARGET_TYPE (TYPE)) : (TYPE))
 376
 377 /* Returns a value object which is the result of applying the operation
 378    specified by OPCODE to the given arguments.  */
 379 static PyObject *
 380 valpy_binop (enum valpy_opcode opcode, PyObject *self, PyObject *other)
 381 {
 382   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 383   volatile struct gdb_exception except;
 384
 385   TRY_CATCH (except, RETURN_MASK_ALL)
 386     {
 387       struct value *arg1, *arg2;
 388
 389       /* If the gdb.Value object is the second operand, then it will be passed
 390          to us as the OTHER argument, and SELF will be an entirely different
 391          kind of object, altogether.  Because of this, we can't assume self is
 392          a gdb.Value object and need to convert it from python as well.  */
 393       arg1 = convert_value_from_python (self);
 394       if (arg1 == NULL)
 395         break;
 396
 397       arg2 = convert_value_from_python (other);
 398       if (arg2 == NULL)
 399         break;
 400
 401       switch (opcode)
 402         {
 403         case VALPY_ADD:
 404           {
 405             struct type *ltype = value_type (arg1);
 406             struct type *rtype = value_type (arg2);
 407
 408             CHECK_TYPEDEF (ltype);
 409             ltype = STRIP_REFERENCE (ltype);
 410             CHECK_TYPEDEF (rtype);
 411             rtype = STRIP_REFERENCE (rtype);
 412
 413             if (TYPE_CODE (ltype) == TYPE_CODE_PTR)
 414               res_val = value_ptradd (arg1, arg2);
 415             else if (TYPE_CODE (rtype) == TYPE_CODE_PTR)
 416               res_val = value_ptradd (arg2, arg1);
 417             else
 418               res_val = value_binop (arg1, arg2, BINOP_ADD);
 419           }
 420           break;
 421         case VALPY_SUB:
 422           {
 423             struct type *ltype = value_type (arg1);
 424             struct type *rtype = value_type (arg2);
 425
 426             CHECK_TYPEDEF (ltype);
 427             ltype = STRIP_REFERENCE (ltype);
 428             CHECK_TYPEDEF (rtype);
 429             rtype = STRIP_REFERENCE (rtype);
 430
 431             if (TYPE_CODE (ltype) == TYPE_CODE_PTR)
 432               {
 433                 if (TYPE_CODE (rtype) == TYPE_CODE_PTR)
 434                     /* A ptrdiff_t for the target would be preferable
 435                        here.  */
 436                     res_val = value_from_longest (builtin_type_pyint,
 437                                                   value_ptrdiff (arg1, arg2));
 438                 else
 439                   res_val = value_ptrsub (arg1, arg2);
 440               }
 441             else
 442               res_val = value_binop (arg1, arg2, BINOP_SUB);
 443           }
 444           break;
 445         case VALPY_MUL:
 446           res_val = value_binop (arg1, arg2, BINOP_MUL);
 447           break;
 448         case VALPY_DIV:
 449           res_val = value_binop (arg1, arg2, BINOP_DIV);
 450           break;
 451         case VALPY_REM:
 452           res_val = value_binop (arg1, arg2, BINOP_REM);
 453           break;
 454         case VALPY_POW:
 455           res_val = value_binop (arg1, arg2, BINOP_EXP);
 456           break;
 457         case VALPY_LSH:
 458           res_val = value_binop (arg1, arg2, BINOP_LSH);
 459           break;
 460         case VALPY_RSH:
 461           res_val = value_binop (arg1, arg2, BINOP_RSH);
 462           break;
 463         case VALPY_BITAND:
 464           res_val = value_binop (arg1, arg2, BINOP_BITWISE_AND);
 465           break;
 466         case VALPY_BITOR:
 467           res_val = value_binop (arg1, arg2, BINOP_BITWISE_IOR);
 468           break;
 469         case VALPY_BITXOR:
 470           res_val = value_binop (arg1, arg2, BINOP_BITWISE_XOR);
 471           break;
 472         }
 473     }
 474   GDB_PY_HANDLE_EXCEPTION (except);
 475
 476   return res_val ? value_to_value_object (res_val) : NULL;
 477 }
 478
 479 static PyObject *
 480 valpy_add (PyObject *self, PyObject *other)
 481 {
 482   return valpy_binop (VALPY_ADD, self, other);
 483 }
 484
 485 static PyObject *
 486 valpy_subtract (PyObject *self, PyObject *other)
 487 {
 488   return valpy_binop (VALPY_SUB, self, other);
 489 }
 490
 491 static PyObject *
 492 valpy_multiply (PyObject *self, PyObject *other)
 493 {
 494   return valpy_binop (VALPY_MUL, self, other);
 495 }
 496
 497 static PyObject *
 498 valpy_divide (PyObject *self, PyObject *other)
 499 {
 500   return valpy_binop (VALPY_DIV, self, other);
 501 }
 502
 503 static PyObject *
 504 valpy_remainder (PyObject *self, PyObject *other)
 505 {
 506   return valpy_binop (VALPY_REM, self, other);
 507 }
 508
 509 static PyObject *
 510 valpy_power (PyObject *self, PyObject *other, PyObject *unused)
 511 {
 512   /* We don't support the ternary form of pow.  I don't know how to express
 513      that, so let's just throw NotImplementedError to at least do something
 514      about it.  */
 515   if (unused != Py_None)
 516     {
 517       PyErr_SetString (PyExc_NotImplementedError,
 518                        "Invalid operation on gdb.Value.");
 519       return NULL;
 520     }
 521
 522   return valpy_binop (VALPY_POW, self, other);
 523 }
 524
 525 static PyObject *
 526 valpy_negative (PyObject *self)
 527 {
 528   struct value *val = NULL;
 529   volatile struct gdb_exception except;
 530
 531   TRY_CATCH (except, RETURN_MASK_ALL)
 532     {
 533       val = value_neg (((value_object *) self)->value);
 534     }
 535   GDB_PY_HANDLE_EXCEPTION (except);
 536
 537   return value_to_value_object (val);
 538 }
 539
 540 static PyObject *
 541 valpy_positive (PyObject *self)
 542 {
 543   struct value *copy = value_copy (((value_object *) self)->value);
 544
 545   return value_to_value_object (copy);
 546 }
 547
 548 static PyObject *
 549 valpy_absolute (PyObject *self)
 550 {
 551   if (value_less (((value_object *) self)->value,
 552                   value_from_longest (builtin_type_int8, 0)))
 553     return valpy_negative (self);
 554   else
 555     return valpy_positive (self);
 556 }
 557
 558 /* Implements boolean evaluation of gdb.Value.  */
 559 static int
 560 valpy_nonzero (PyObject *self)
 561 {
 562   value_object *self_value = (value_object *) self;
 563   struct type *type;
 564
 565   type = check_typedef (value_type (self_value->value));
 566
 567   if (is_integral_type (type) || TYPE_CODE (type) == TYPE_CODE_PTR)
 568     return !!value_as_long (self_value->value);
 569   else if (TYPE_CODE (type) == TYPE_CODE_FLT)
 570     return value_as_double (self_value->value) != 0;
 571   else if (TYPE_CODE (type) == TYPE_CODE_DECFLOAT)
 572     return !decimal_is_zero (value_contents (self_value->value),
 573                              TYPE_LENGTH (type));
 574   else
 575     {
 576       PyErr_SetString (PyExc_TypeError, _("Attempted truth testing on invalid "
 577                                           "gdb.Value type."));
 578       return 0;
 579     }
 580 }
 581
 582 /* Implements ~ for value objects.  */
 583 static PyObject *
 584 valpy_invert (PyObject *self)
 585 {
 586   struct value *val = NULL;
 587   volatile struct gdb_exception except;
 588
 589   TRY_CATCH (except, RETURN_MASK_ALL)
 590     {
 591       val = value_complement (((value_object *) self)->value);
 592     }
 593   GDB_PY_HANDLE_EXCEPTION (except);
 594
 595   return value_to_value_object (val);
 596 }
 597
 598 /* Implements left shift for value objects.  */
 599 static PyObject *
 600 valpy_lsh (PyObject *self, PyObject *other)
 601 {
 602   return valpy_binop (VALPY_LSH, self, other);
 603 }
 604
 605 /* Implements right shift for value objects.  */
 606 static PyObject *
 607 valpy_rsh (PyObject *self, PyObject *other)
 608 {
 609   return valpy_binop (VALPY_RSH, self, other);
 610 }
 611
 612 /* Implements bitwise and for value objects.  */
 613 static PyObject *
 614 valpy_and (PyObject *self, PyObject *other)
 615 {
 616   return valpy_binop (VALPY_BITAND, self, other);
 617 }
 618
 619 /* Implements bitwise or for value objects.  */
 620 static PyObject *
 621 valpy_or (PyObject *self, PyObject *other)
 622 {
 623   return valpy_binop (VALPY_BITOR, self, other);
 624 }
 625
 626 /* Implements bitwise xor for value objects.  */
 627 static PyObject *
 628 valpy_xor (PyObject *self, PyObject *other)
 629 {
 630   return valpy_binop (VALPY_BITXOR, self, other);
 631 }
 632
 633 /* Implements comparison operations for value objects.  */
 634 static PyObject *
 635 valpy_richcompare (PyObject *self, PyObject *other, int op)
 636 {
 637   int result = 0;
 638   struct value *value_other;
 639   volatile struct gdb_exception except;
 640
 641   if (other == Py_None)
 642     /* Comparing with None is special.  From what I can tell, in Python
 643        None is smaller than anything else.  */
 644     switch (op) {
 645       case Py_LT:
 646       case Py_LE:
 647       case Py_EQ:
 648         Py_RETURN_FALSE;
 649       case Py_NE:
 650       case Py_GT:
 651       case Py_GE:
 652         Py_RETURN_TRUE;
 653       default:
 654         /* Can't happen.  */
 655         PyErr_SetString (PyExc_NotImplementedError,
 656                          "Invalid operation on gdb.Value.");
 657         return NULL;
 658     }
 659
 660   TRY_CATCH (except, RETURN_MASK_ALL)
 661     {
 662       value_other = convert_value_from_python (other);
 663       if (value_other == NULL)
 664         return NULL;
 665
 666       switch (op) {
 667         case Py_LT:
 668           result = value_less (((value_object *) self)->value, value_other);
 669           break;
 670         case Py_LE:
 671           result = value_less (((value_object *) self)->value, value_other)
 672             || value_equal (((value_object *) self)->value, value_other);
 673           break;
 674         case Py_EQ:
 675           result = value_equal (((value_object *) self)->value, value_other);
 676           break;
 677         case Py_NE:
 678           result = !value_equal (((value_object *) self)->value, value_other);
 679           break;
 680         case Py_GT:
 681           result = value_less (value_other, ((value_object *) self)->value);
 682           break;
 683         case Py_GE:
 684           result = value_less (value_other, ((value_object *) self)->value)
 685             || value_equal (((value_object *) self)->value, value_other);
 686           break;
 687         default:
 688           /* Can't happen.  */
 689           PyErr_SetString (PyExc_NotImplementedError,
 690                            "Invalid operation on gdb.Value.");
 691           return NULL;
 692       }
 693     }
 694   GDB_PY_HANDLE_EXCEPTION (except);
 695
 696   if (result == 1)
 697     Py_RETURN_TRUE;
 698
 699   Py_RETURN_FALSE;
 700 }
 701
 702 /* Helper function to determine if a type is "int-like".  */
 703 static int
 704 is_intlike (struct type *type, int ptr_ok)
 705 {
 706   CHECK_TYPEDEF (type);
 707   return (TYPE_CODE (type) == TYPE_CODE_INT
 708           || TYPE_CODE (type) == TYPE_CODE_ENUM
 709           || TYPE_CODE (type) == TYPE_CODE_BOOL
 710           || TYPE_CODE (type) == TYPE_CODE_CHAR
 711           || (ptr_ok && TYPE_CODE (type) == TYPE_CODE_PTR));
 712 }
 713
 714 /* Implements conversion to int.  */
 715 static PyObject *
 716 valpy_int (PyObject *self)
 717 {
 718   struct value *value = ((value_object *) self)->value;
 719   struct type *type = value_type (value);
 720   LONGEST l = 0;
 721   volatile struct gdb_exception except;
 722
 723   CHECK_TYPEDEF (type);
 724   if (!is_intlike (type, 0))
 725     {
 726       PyErr_SetString (PyExc_RuntimeError, "cannot convert value to int");
 727       return NULL;
 728     }
 729
 730   TRY_CATCH (except, RETURN_MASK_ALL)
 731     {
 732       l = value_as_long (value);
 733     }
 734   GDB_PY_HANDLE_EXCEPTION (except);
 735
 736   return PyInt_FromLong (l);
 737 }
 738
 739 /* Implements conversion to long.  */
 740 static PyObject *
 741 valpy_long (PyObject *self)
 742 {
 743   struct value *value = ((value_object *) self)->value;
 744   struct type *type = value_type (value);
 745   LONGEST l = 0;
 746   volatile struct gdb_exception except;
 747
 748   if (!is_intlike (type, 1))
 749     {
 750       PyErr_SetString (PyExc_RuntimeError, "cannot convert value to long");
 751       return NULL;
 752     }
 753
 754   TRY_CATCH (except, RETURN_MASK_ALL)
 755     {
 756       l = value_as_long (value);
 757     }
 758   GDB_PY_HANDLE_EXCEPTION (except);
 759
 760   return PyLong_FromLong (l);
 761 }
 762
 763 /* Implements conversion to float.  */
 764 static PyObject *
 765 valpy_float (PyObject *self)
 766 {
 767   struct value *value = ((value_object *) self)->value;
 768   struct type *type = value_type (value);
 769   double d = 0;
 770   volatile struct gdb_exception except;
 771
 772   CHECK_TYPEDEF (type);
 773   if (TYPE_CODE (type) != TYPE_CODE_FLT)
 774     {
 775       PyErr_SetString (PyExc_RuntimeError, "cannot convert value to float");
 776       return NULL;
 777     }
 778
 779   TRY_CATCH (except, RETURN_MASK_ALL)
 780     {
 781       d = value_as_double (value);
 782     }
 783   GDB_PY_HANDLE_EXCEPTION (except);
 784
 785   return PyFloat_FromDouble (d);
 786 }
 787
 788 /* Returns an object for a value which is released from the all_values chain,
 789    so its lifetime is not bound to the execution of a command.  */
 790 PyObject *
 791 value_to_value_object (struct value *val)
 792 {
 793   value_object *val_obj;
 794
 795   val_obj = PyObject_New (value_object, &value_object_type);
 796   if (val_obj != NULL)
 797     {
 798       val_obj->value = val;
 799       val_obj->address = NULL;
 800       val_obj->type = NULL;
 801       release_value (val);
 802       value_prepend_to_list (&values_in_python, val);
 803     }
 804
 805   return (PyObject *) val_obj;
 806 }
 807
 808 /* Try to convert a Python value to a gdb value.  If the value cannot
 809    be converted, set a Python exception and return NULL.  */
 810
 811 struct value *
 812 convert_value_from_python (PyObject *obj)
 813 {
 814   struct value *value = NULL; /* -Wall */
 815   PyObject *target_str, *unicode_str;
 816   struct cleanup *old;
 817   volatile struct gdb_exception except;
 818   int cmp;
 819
 820   gdb_assert (obj != NULL);
 821
 822   TRY_CATCH (except, RETURN_MASK_ALL)
 823     {
 824       if (PyBool_Check (obj))
 825         {
 826           cmp = PyObject_IsTrue (obj);
 827           if (cmp >= 0)
 828             value = value_from_longest (builtin_type_pybool, cmp);
 829         }
 830       else if (PyInt_Check (obj))
 831         {
 832           long l = PyInt_AsLong (obj);
 833
 834           if (! PyErr_Occurred ())
 835             value = value_from_longest (builtin_type_pyint, l);
 836         }
 837       else if (PyLong_Check (obj))
 838         {
 839           LONGEST l = PyLong_AsLongLong (obj);
 840
 841           if (! PyErr_Occurred ())
 842             value = value_from_longest (builtin_type_pylong, l);
 843         }
 844       else if (PyFloat_Check (obj))
 845         {
 846           double d = PyFloat_AsDouble (obj);
 847
 848           if (! PyErr_Occurred ())
 849             value = value_from_double (builtin_type_pyfloat, d);
 850         }
 851       else if (gdbpy_is_string (obj))
 852         {
 853           char *s;
 854
 855           s = python_string_to_target_string (obj);
 856           if (s != NULL)
 857             {
 858               old = make_cleanup (xfree, s);
 859               value = value_from_string (s);
 860               do_cleanups (old);
 861             }
 862         }
 863       else if (PyObject_TypeCheck (obj, &value_object_type))
 864         value = value_copy (((value_object *) obj)->value);
 865       else
 866         PyErr_Format (PyExc_TypeError, _("Could not convert Python object: %s"),
 867                       PyString_AsString (PyObject_Str (obj)));
 868     }
 869   if (except.reason < 0)
 870     {
 871       PyErr_Format (except.reason == RETURN_QUIT
 872                     ? PyExc_KeyboardInterrupt : PyExc_RuntimeError,
 873                     "%s", except.message);
 874       return NULL;
 875     }
 876
 877   return value;
 878 }
 879
 880 /* Returns value object in the ARGth position in GDB's history.  */
 881 PyObject *
 882 gdbpy_history (PyObject *self, PyObject *args)
 883 {
 884   int i;
 885   struct value *res_val = NULL;   /* Initialize to appease gcc warning.  */
 886   volatile struct gdb_exception except;
 887
 888   if (!PyArg_ParseTuple (args, "i", &i))
 889     return NULL;
 890
 891   TRY_CATCH (except, RETURN_MASK_ALL)
 892     {
 893       res_val = access_value_history (i);
 894     }
 895   GDB_PY_HANDLE_EXCEPTION (except);
 896
 897   return value_to_value_object (res_val);
 898 }
 899
 900 void
 901 gdbpy_initialize_values (void)
 902 {
 903   if (PyType_Ready (&value_object_type) < 0)
 904     return;
 905
 906   Py_INCREF (&value_object_type);
 907   PyModule_AddObject (gdb_module, "Value", (PyObject *) &value_object_type);
 908
 909   values_in_python = NULL;
 910 }
 911
 912 \f
 913
 914 static PyGetSetDef value_object_getset[] = {
 915   { "address", valpy_get_address, NULL, "The address of the value.",
 916     NULL },
 917   { "is_optimized_out", valpy_get_is_optimized_out, NULL,
 918     "Boolean telling whether the value is optimized out (i.e., not available).",
 919     NULL },
 920   { "type", valpy_get_type, NULL, "Type of the value.", NULL },
 921   {NULL}  /* Sentinel */
 922 };
 923
 924 static PyMethodDef value_object_methods[] = {
 925   { "cast", valpy_cast, METH_VARARGS, "Cast the value to the supplied type." },
 926   { "dereference", valpy_dereference, METH_NOARGS, "Dereferences the value." },
 927   { "string", (PyCFunction) valpy_string, METH_VARARGS | METH_KEYWORDS,
 928     "string ([encoding] [, errors]) -> string\n\
 929 Return Unicode string representation of the value." },
 930   {NULL}  /* Sentinel */
 931 };
 932
 933 static PyNumberMethods value_object_as_number = {
 934   valpy_add,
 935   valpy_subtract,
 936   valpy_multiply,
 937   valpy_divide,
 938   valpy_remainder,
 939   NULL,                       /* nb_divmod */
 940   valpy_power,                /* nb_power */
 941   valpy_negative,             /* nb_negative */
 942   valpy_positive,             /* nb_positive */
 943   valpy_absolute,             /* nb_absolute */
 944   valpy_nonzero,              /* nb_nonzero */
 945   valpy_invert,               /* nb_invert */
 946   valpy_lsh,                  /* nb_lshift */
 947   valpy_rsh,                  /* nb_rshift */
 948   valpy_and,                  /* nb_and */
 949   valpy_xor,                  /* nb_xor */
 950   valpy_or,                   /* nb_or */
 951   NULL,                       /* nb_coerce */
 952   valpy_int,                  /* nb_int */
 953   valpy_long,                 /* nb_long */
 954   valpy_float,                /* nb_float */
 955   NULL,                       /* nb_oct */
 956   NULL                        /* nb_hex */
 957 };
 958
 959 static PyMappingMethods value_object_as_mapping = {
 960   valpy_length,
 961   valpy_getitem,
 962   valpy_setitem
 963 };
 964
 965 PyTypeObject value_object_type = {
 966   PyObject_HEAD_INIT (NULL)
 967   0,                              /*ob_size*/
 968   "gdb.Value",                    /*tp_name*/
 969   sizeof (value_object),          /*tp_basicsize*/
 970   0,                              /*tp_itemsize*/
 971   valpy_dealloc,                  /*tp_dealloc*/
 972   0,                              /*tp_print*/
 973   0,                              /*tp_getattr*/
 974   0,                              /*tp_setattr*/
 975   0,                              /*tp_compare*/
 976   0,                              /*tp_repr*/
 977   &value_object_as_number,        /*tp_as_number*/
 978   0,                              /*tp_as_sequence*/
 979   &value_object_as_mapping,       /*tp_as_mapping*/
 980   0,                              /*tp_hash */
 981   0,                              /*tp_call*/
 982   valpy_str,                      /*tp_str*/
 983   0,                              /*tp_getattro*/
 984   0,                              /*tp_setattro*/
 985   0,                              /*tp_as_buffer*/
 986   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES,   /*tp_flags*/
 987   "GDB value object",             /* tp_doc */
 988   0,                              /* tp_traverse */
 989   0,                              /* tp_clear */
 990   valpy_richcompare,              /* tp_richcompare */
 991   0,                              /* tp_weaklistoffset */
 992   0,                              /* tp_iter */
 993   0,                              /* tp_iternext */
 994   value_object_methods,           /* tp_methods */
 995   0,                              /* tp_members */
 996   value_object_getset,            /* tp_getset */
 997   0,                              /* tp_base */
 998   0,                              /* tp_dict */
 999   0,                              /* tp_descr_get */
1000   0,                              /* tp_descr_set */
1001   0,                              /* tp_dictoffset */
1002   0,                              /* tp_init */
1003   0,                              /* tp_alloc */
1004   valpy_new                       /* tp_new */
1005 };
1006
1007 #endif /* HAVE_PYTHON */