dlls/wbemprox/query.c

   1 /*
   2  * Copyright 2012 Hans Leidekker for CodeWeavers
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  17  */
  18
  19 #define COBJMACROS
  20
  21 #include "config.h"
  22 #include <stdarg.h>
  23
  24 #include "windef.h"
  25 #include "winbase.h"
  26 #include "wbemcli.h"
  27
  28 #include "wine/debug.h"
  29 #include "wbemprox_private.h"
  30
  31 WINE_DEFAULT_DEBUG_CHANNEL(wbemprox);
  32
  33 HRESULT create_view( const struct property *proplist, const WCHAR *class,
  34                      const struct expr *cond, struct view **ret )
  35 {
  36     struct view *view = heap_alloc( sizeof(struct view) );
  37
  38     if (!view) return E_OUTOFMEMORY;
  39     view->proplist = proplist;
  40     view->table    = get_table( class );
  41     view->cond     = cond;
  42     view->result   = NULL;
  43     view->count    = 0;
  44     *ret = view;
  45     return S_OK;
  46 }
  47
  48 void destroy_view( struct view *view )
  49 {
  50     free_table( view->table );
  51     heap_free( view->result );
  52     heap_free( view );
  53 }
  54
  55 static BOOL eval_like( const WCHAR *lstr, const WCHAR *rstr )
  56 {
  57     const WCHAR *p = lstr, *q = rstr;
  58
  59     while (*p && *q)
  60     {
  61         if (*q == '%')
  62         {
  63             while (*q == '%') q++;
  64             if (!*q) return TRUE;
  65             while (*p && toupperW( p[1] ) != toupperW( q[1] )) p++;
  66             if (!*p) return TRUE;
  67         }
  68         if (toupperW( *p++ ) != toupperW( *q++ )) return FALSE;
  69     }
  70     return TRUE;
  71 }
  72
  73 static HRESULT eval_strcmp( UINT op, const WCHAR *lstr, const WCHAR *rstr, LONGLONG *val )
  74 {
  75     switch (op)
  76     {
  77     case OP_EQ:
  78         *val = !strcmpW( lstr, rstr );
  79         break;
  80     case OP_GT:
  81         *val = strcmpW( lstr, rstr ) > 0;
  82         break;
  83     case OP_LT:
  84         *val = strcmpW( lstr, rstr ) < 0;
  85         break;
  86     case OP_LE:
  87         *val = strcmpW( lstr, rstr ) <= 0;
  88         break;
  89     case OP_GE:
  90         *val = strcmpW( lstr, rstr ) >= 0;
  91         break;
  92     case OP_NE:
  93         *val = strcmpW( lstr, rstr );
  94         break;
  95     case OP_LIKE:
  96         *val = eval_like( lstr, rstr );
  97         break;
  98     default:
  99         ERR("unhandled operator %u\n", op);
 100         return WBEM_E_INVALID_QUERY;
 101     }
 102     return S_OK;
 103 }
 104
 105 static inline BOOL is_strcmp( const struct complex_expr *expr )
 106 {
 107     return ((expr->left->type == EXPR_PROPVAL && expr->right->type == EXPR_SVAL) ||
 108             (expr->left->type == EXPR_SVAL && expr->right->type == EXPR_PROPVAL));
 109 }
 110
 111 static HRESULT eval_cond( const struct table *, UINT, const struct expr *, LONGLONG * );
 112
 113 static HRESULT eval_binary( const struct table *table, UINT row, const struct complex_expr *expr,
 114                             LONGLONG *val )
 115 {
 116     HRESULT lret, rret;
 117     LONGLONG lval, rval;
 118
 119     lret = eval_cond( table, row, expr->left, &lval );
 120     rret = eval_cond( table, row, expr->right, &rval );
 121     if (lret != S_OK || rret != S_OK) return WBEM_E_INVALID_QUERY;
 122
 123     if (is_strcmp( expr ))
 124     {
 125         const WCHAR *lstr = (const WCHAR *)(INT_PTR)lval;
 126         const WCHAR *rstr = (const WCHAR *)(INT_PTR)rval;
 127
 128         return eval_strcmp( expr->op, lstr, rstr, val );
 129     }
 130     switch (expr->op)
 131     {
 132     case OP_EQ:
 133         *val = (lval == rval);
 134         break;
 135     case OP_AND:
 136         *val = (lval && rval);
 137         break;
 138     case OP_OR:
 139         *val = (lval || rval);
 140         break;
 141     case OP_GT:
 142         *val = (lval > rval);
 143         break;
 144     case OP_LT:
 145         *val = (lval < rval);
 146         break;
 147     case OP_LE:
 148         *val = (lval <= rval);
 149         break;
 150     case OP_GE:
 151         *val = (lval >= rval);
 152         break;
 153     case OP_NE:
 154         *val = (lval != rval);
 155         break;
 156     default:
 157         ERR("unhandled operator %u\n", expr->op);
 158         return WBEM_E_INVALID_QUERY;
 159     }
 160     return S_OK;
 161 }
 162
 163 static HRESULT eval_unary( const struct table *table, UINT row, const struct complex_expr *expr,
 164                            LONGLONG *val )
 165
 166 {
 167     HRESULT hr;
 168     UINT column;
 169     LONGLONG lval;
 170
 171     hr = get_column_index( table, expr->left->u.propval->name, &column );
 172     if (hr != S_OK)
 173         return hr;
 174
 175     hr = get_value( table, row, column, &lval );
 176     if (hr != S_OK)
 177         return hr;
 178
 179     switch (expr->op)
 180     {
 181     case OP_ISNULL:
 182         *val = !lval;
 183         break;
 184     case OP_NOTNULL:
 185         *val = lval;
 186         break;
 187     default:
 188         ERR("unknown operator %u\n", expr->op);
 189         return WBEM_E_INVALID_QUERY;
 190     }
 191     return S_OK;
 192 }
 193
 194 static HRESULT eval_propval( const struct table *table, UINT row, const struct property *propval,
 195                              LONGLONG *val )
 196
 197 {
 198     HRESULT hr;
 199     UINT column;
 200
 201     hr = get_column_index( table, propval->name, &column );
 202     if (hr != S_OK)
 203         return hr;
 204
 205     return get_value( table, row, column, val );
 206 }
 207
 208 static HRESULT eval_cond( const struct table *table, UINT row, const struct expr *cond,
 209                           LONGLONG *val )
 210 {
 211     if (!cond)
 212     {
 213         *val = 1;
 214         return S_OK;
 215     }
 216     switch (cond->type)
 217     {
 218     case EXPR_COMPLEX:
 219         return eval_binary( table, row, &cond->u.expr, val );
 220     case EXPR_UNARY:
 221         return eval_unary( table, row, &cond->u.expr, val );
 222     case EXPR_PROPVAL:
 223         return eval_propval( table, row, cond->u.propval, val );
 224     case EXPR_SVAL:
 225         *val = (LONGLONG)(INT_PTR)cond->u.sval;
 226         return S_OK;
 227     case EXPR_IVAL:
 228     case EXPR_BVAL:
 229         *val = cond->u.ival;
 230         return S_OK;
 231     default:
 232         ERR("invalid expression type\n");
 233         break;
 234     }
 235     return WBEM_E_INVALID_QUERY;
 236 }
 237
 238 static HRESULT execute_view( struct view *view )
 239 {
 240     UINT i, j = 0, len;
 241
 242     if (!view->table || !view->table->num_rows) return S_OK;
 243
 244     len = min( view->table->num_rows, 16 );
 245     if (!(view->result = heap_alloc( len * sizeof(UINT) ))) return E_OUTOFMEMORY;
 246
 247     for (i = 0; i < view->table->num_rows; i++)
 248     {
 249         HRESULT hr;
 250         LONGLONG val = 0;
 251
 252         if (j >= len)
 253         {
 254             UINT *tmp;
 255             len *= 2;
 256             if (!(tmp = heap_realloc( view->result, len * sizeof(UINT) ))) return E_OUTOFMEMORY;
 257             view->result = tmp;
 258         }
 259         if ((hr = eval_cond( view->table, i, view->cond, &val )) != S_OK) return hr;
 260         if (val) view->result[j++] = i;
 261     }
 262     view->count = j;
 263     return S_OK;
 264 }
 265
 266 static struct query *create_query(void)
 267 {
 268     struct query *query;
 269
 270     if (!(query = heap_alloc( sizeof(*query) ))) return NULL;
 271     list_init( &query->mem );
 272     query->refs = 1;
 273     return query;
 274 }
 275
 276 static void free_query( struct query *query )
 277 {
 278     struct list *mem, *next;
 279
 280     destroy_view( query->view );
 281     LIST_FOR_EACH_SAFE( mem, next, &query->mem )
 282     {
 283         heap_free( mem );
 284     }
 285     heap_free( query );
 286 }
 287
 288 void addref_query( struct query *query )
 289 {
 290     InterlockedIncrement( &query->refs );
 291 }
 292
 293 void release_query( struct query *query )
 294 {
 295     if (!InterlockedDecrement( &query->refs )) free_query( query );
 296 }
 297
 298 HRESULT exec_query( const WCHAR *str, IEnumWbemClassObject **result )
 299 {
 300     HRESULT hr;
 301     struct query *query;
 302
 303     *result = NULL;
 304     if (!(query = create_query())) return E_OUTOFMEMORY;
 305     hr = parse_query( str, &query->view, &query->mem );
 306     if (hr != S_OK) goto done;
 307     hr = execute_view( query->view );
 308     if (hr != S_OK) goto done;
 309     hr = EnumWbemClassObject_create( NULL, query, (void **)result );
 310
 311 done:
 312     release_query( query );
 313     return hr;
 314 }
 315
 316 static BOOL is_selected_prop( const struct view *view, const WCHAR *name )
 317 {
 318     const struct property *prop = view->proplist;
 319
 320     if (!prop) return TRUE;
 321     while (prop)
 322     {
 323         if (!strcmpiW( prop->name, name )) return TRUE;
 324         prop = prop->next;
 325     }
 326     return FALSE;
 327 }
 328
 329 static BOOL is_system_prop( const WCHAR *name )
 330 {
 331     return (name[0] == '_' && name[1] == '_');
 332 }
 333
 334 static BSTR build_servername( const struct view *view )
 335 {
 336     WCHAR server[MAX_COMPUTERNAME_LENGTH + 1], *p;
 337     DWORD len = sizeof(server)/sizeof(server[0]);
 338
 339     if (view->proplist) return NULL;
 340
 341     if (!(GetComputerNameW( server, &len ))) return NULL;
 342     for (p = server; *p; p++) *p = toupperW( *p );
 343     return SysAllocString( server );
 344 }
 345
 346 static BSTR build_classname( const struct view *view )
 347 {
 348     return SysAllocString( view->table->name );
 349 }
 350
 351 static BSTR build_namespace( const struct view *view )
 352 {
 353     static const WCHAR cimv2W[] = {'R','O','O','T','\\','C','I','M','V','2',0};
 354
 355     if (view->proplist) return NULL;
 356     return SysAllocString( cimv2W );
 357 }
 358
 359 static BSTR build_proplist( const struct view *view, UINT index, UINT count, UINT *len )
 360 {
 361     static const WCHAR fmtW[] = {'%','s','=','%','s',0};
 362     UINT i, j, offset, row = view->result[index];
 363     BSTR *values, ret = NULL;
 364
 365     if (!(values = heap_alloc( count * sizeof(BSTR) ))) return NULL;
 366
 367     *len = j = 0;
 368     for (i = 0; i < view->table->num_cols; i++)
 369     {
 370         if (view->table->columns[i].type & COL_FLAG_KEY)
 371         {
 372             const WCHAR *name = view->table->columns[i].name;
 373
 374             values[j] = get_value_bstr( view->table, row, i );
 375             *len += strlenW( fmtW ) + strlenW( name ) + strlenW( values[j] );
 376             j++;
 377         }
 378     }
 379     if ((ret = SysAllocStringLen( NULL, *len )))
 380     {
 381         offset = j = 0;
 382         for (i = 0; i < view->table->num_cols; i++)
 383         {
 384             if (view->table->columns[i].type & COL_FLAG_KEY)
 385             {
 386                 const WCHAR *name = view->table->columns[i].name;
 387
 388                 offset += sprintfW( ret + offset, fmtW, name, values[j] );
 389                 if (j < count - 1) ret[offset++] = ',';
 390                 j++;
 391             }
 392         }
 393     }
 394     for (i = 0; i < count; i++) SysFreeString( values[i] );
 395     heap_free( values );
 396     return ret;
 397 }
 398
 399 static UINT count_key_columns( const struct view *view )
 400 {
 401     UINT i, num_keys = 0;
 402
 403     for (i = 0; i < view->table->num_cols; i++)
 404     {
 405         if (view->table->columns[i].type & COL_FLAG_KEY) num_keys++;
 406     }
 407     return num_keys;
 408 }
 409
 410 static BSTR build_relpath( const struct view *view, UINT index, const WCHAR *name )
 411 {
 412     static const WCHAR fmtW[] = {'%','s','.','%','s',0};
 413     BSTR class, proplist, ret = NULL;
 414     UINT num_keys, len;
 415
 416     if (view->proplist) return NULL;
 417
 418     if (!(class = build_classname( view ))) return NULL;
 419     if (!(num_keys = count_key_columns( view ))) return class;
 420     if (!(proplist = build_proplist( view, index, num_keys, &len ))) goto done;
 421
 422     len += strlenW( fmtW ) + SysStringLen( class );
 423     if (!(ret = SysAllocStringLen( NULL, len ))) goto done;
 424     sprintfW( ret, fmtW, class, proplist );
 425
 426 done:
 427     SysFreeString( class );
 428     SysFreeString( proplist );
 429     return ret;
 430 }
 431
 432 static BSTR build_path( const struct view *view, UINT index, const WCHAR *name )
 433 {
 434     static const WCHAR fmtW[] = {'\\','\\','%','s','\\','%','s',':','%','s',0};
 435     BSTR server, namespace = NULL, relpath = NULL, ret = NULL;
 436     UINT len;
 437
 438     if (view->proplist) return NULL;
 439
 440     if (!(server = build_servername( view ))) return NULL;
 441     if (!(namespace = build_namespace( view ))) goto done;
 442     if (!(relpath = build_relpath( view, index, name ))) goto done;
 443
 444     len = strlenW( fmtW ) + SysStringLen( server ) + SysStringLen( namespace ) + SysStringLen( relpath );
 445     if (!(ret = SysAllocStringLen( NULL, len ))) goto done;
 446     sprintfW( ret, fmtW, server, namespace, relpath );
 447
 448 done:
 449     SysFreeString( server );
 450     SysFreeString( namespace );
 451     SysFreeString( relpath );
 452     return ret;
 453 }
 454
 455 static inline BOOL is_method( const struct table *table, UINT column )
 456 {
 457     return table->columns[column].type & COL_FLAG_METHOD;
 458 }
 459
 460 static UINT count_properties( const struct view *view )
 461 {
 462     UINT i, num_props = 0;
 463
 464     for (i = 0; i < view->table->num_cols; i++)
 465     {
 466         if (!is_method( view->table, i)) num_props++;
 467     }
 468     return num_props;
 469 }
 470
 471 static UINT count_selected_properties( const struct view *view )
 472 {
 473     const struct property *prop = view->proplist;
 474     UINT count;
 475
 476     if (!prop) return count_properties( view );
 477
 478     count = 1;
 479     while ((prop = prop->next)) count++;
 480     return count;
 481 }
 482
 483 static HRESULT get_system_propval( const struct view *view, UINT index, const WCHAR *name,
 484                                    VARIANT *ret, CIMTYPE *type, LONG *flavor )
 485 {
 486     static const WCHAR classW[] = {'_','_','C','L','A','S','S',0};
 487     static const WCHAR genusW[] = {'_','_','G','E','N','U','S',0};
 488     static const WCHAR pathW[] = {'_','_','P','A','T','H',0};
 489     static const WCHAR namespaceW[] = {'_','_','N','A','M','E','S','P','A','C','E',0};
 490     static const WCHAR propcountW[] = {'_','_','P','R','O','P','E','R','T','Y','_','C','O','U','N','T',0};
 491     static const WCHAR relpathW[] = {'_','_','R','E','L','P','A','T','H',0};
 492     static const WCHAR serverW[] = {'_','_','S','E','R','V','E','R',0};
 493
 494     if (flavor) *flavor = WBEM_FLAVOR_ORIGIN_SYSTEM;
 495
 496     if (!strcmpiW( name, classW ))
 497     {
 498         V_VT( ret ) = VT_BSTR;
 499         V_BSTR( ret ) = build_classname( view );
 500         if (type) *type = CIM_STRING;
 501         return S_OK;
 502     }
 503     if (!strcmpiW( name, genusW ))
 504     {
 505         V_VT( ret ) = VT_I4;
 506         V_I4( ret ) = WBEM_GENUS_INSTANCE; /* FIXME */
 507         if (type) *type = CIM_SINT32;
 508         return S_OK;
 509     }
 510     else if (!strcmpiW( name, namespaceW ))
 511     {
 512         V_VT( ret ) = VT_BSTR;
 513         V_BSTR( ret ) = build_namespace( view );
 514         if (type) *type = CIM_STRING;
 515         return S_OK;
 516     }
 517     else if (!strcmpiW( name, pathW ))
 518     {
 519         V_VT( ret ) = VT_BSTR;
 520         V_BSTR( ret ) = build_path( view, index, name );
 521         if (type) *type = CIM_STRING;
 522         return S_OK;
 523     }
 524     if (!strcmpiW( name, propcountW ))
 525     {
 526         V_VT( ret ) = VT_I4;
 527         V_I4( ret ) = count_selected_properties( view );
 528         if (type) *type = CIM_SINT32;
 529         return S_OK;
 530     }
 531     else if (!strcmpiW( name, relpathW ))
 532     {
 533         V_VT( ret ) = VT_BSTR;
 534         V_BSTR( ret ) = build_relpath( view, index, name );
 535         if (type) *type = CIM_STRING;
 536         return S_OK;
 537     }
 538     else if (!strcmpiW( name, serverW ))
 539     {
 540         V_VT( ret ) = VT_BSTR;
 541         V_BSTR( ret ) = build_servername( view );
 542         if (type) *type = CIM_STRING;
 543         return S_OK;
 544     }
 545     FIXME("system property %s not implemented\n", debugstr_w(name));
 546     return WBEM_E_NOT_FOUND;
 547 }
 548
 549 static void set_variant( VARTYPE vartype, LONGLONG val, BSTR val_bstr, VARIANT *ret )
 550 {
 551     switch (vartype)
 552     {
 553     case VT_BOOL:
 554         V_VT( ret ) = VT_BOOL;
 555         V_BOOL( ret ) = val;
 556         return;
 557     case VT_BSTR:
 558         V_VT( ret ) = VT_BSTR;
 559         V_BSTR( ret ) = val_bstr;
 560         return;
 561     case VT_I2:
 562         V_VT( ret ) = VT_I2;
 563         V_I2( ret ) = val;
 564         return;
 565     case VT_UI2:
 566         V_VT( ret ) = VT_UI2;
 567         V_UI2( ret ) = val;
 568         return;
 569     case VT_I4:
 570         V_VT( ret ) = VT_I4;
 571         V_I4( ret ) = val;
 572         return;
 573     case VT_UI4:
 574         V_VT( ret ) = VT_UI4;
 575         V_UI4( ret ) = val;
 576         return;
 577     case VT_NULL:
 578         V_VT( ret ) = VT_NULL;
 579         return;
 580     default:
 581         ERR("unhandled variant type %u\n", vartype);
 582         return;
 583     }
 584 }
 585
 586 HRESULT get_propval( const struct view *view, UINT index, const WCHAR *name, VARIANT *ret,
 587                      CIMTYPE *type, LONG *flavor )
 588 {
 589     HRESULT hr;
 590     UINT column, row = view->result[index];
 591     VARTYPE vartype;
 592     BSTR val_bstr = NULL;
 593     LONGLONG val;
 594
 595     if (is_system_prop( name )) return get_system_propval( view, index, name, ret, type, flavor );
 596     if (!is_selected_prop( view, name )) return WBEM_E_NOT_FOUND;
 597
 598     hr = get_column_index( view->table, name, &column );
 599     if (hr != S_OK || is_method( view->table, column )) return WBEM_E_NOT_FOUND;
 600
 601     vartype = view->table->columns[column].vartype;
 602
 603     hr = get_value( view->table, row, column, &val );
 604     if (hr != S_OK) return hr;
 605
 606     switch (view->table->columns[column].type & COL_TYPE_MASK)
 607     {
 608     case CIM_BOOLEAN:
 609         if (!vartype) vartype = VT_BOOL;
 610         break;
 611     case CIM_STRING:
 612     case CIM_DATETIME:
 613         if (val)
 614         {
 615             vartype = VT_BSTR;
 616             val_bstr = SysAllocString( (const WCHAR *)(INT_PTR)val );
 617         }
 618         else
 619             vartype = VT_NULL;
 620         break;
 621     case CIM_SINT16:
 622         if (!vartype) vartype = VT_I2;
 623         break;
 624     case CIM_UINT16:
 625         if (!vartype) vartype = VT_UI2;
 626         break;
 627     case CIM_SINT32:
 628         if (!vartype) vartype = VT_I4;
 629         break;
 630     case CIM_UINT32:
 631         if (!vartype) vartype = VT_UI4;
 632         break;
 633     case CIM_SINT64:
 634         vartype = VT_BSTR;
 635         val_bstr = get_value_bstr( view->table, row, column );
 636         break;
 637     case CIM_UINT64:
 638         vartype = VT_BSTR;
 639         val_bstr = get_value_bstr( view->table, row, column );
 640         break;
 641     default:
 642         ERR("unhandled column type %u\n", view->table->columns[column].type);
 643         return WBEM_E_FAILED;
 644     }
 645     set_variant( vartype, val, val_bstr, ret );
 646     if (type) *type = view->table->columns[column].type & COL_TYPE_MASK;
 647     if (flavor) *flavor = 0;
 648     return S_OK;
 649 }
 650
 651 static HRESULT variant_to_longlong( VARIANT *var, LONGLONG *val, CIMTYPE *type )
 652 {
 653     if (!var)
 654     {
 655         *val = 0;
 656         return S_OK;
 657     }
 658     switch (V_VT( var ))
 659     {
 660     case VT_BOOL:
 661         *val = V_BOOL( var );
 662         *type = CIM_BOOLEAN;
 663         break;
 664     case VT_BSTR:
 665         *val = (INT_PTR)SysAllocString( V_BSTR( var ) );
 666         if (!*val) return E_OUTOFMEMORY;
 667         *type = CIM_STRING;
 668         break;
 669     case VT_I2:
 670         *val = V_I2( var );
 671         *type = CIM_SINT16;
 672         break;
 673     case VT_UI2:
 674         *val = V_UI2( var );
 675         *type = CIM_UINT16;
 676         break;
 677     case VT_I4:
 678         *val = V_I4( var );
 679         *type = CIM_SINT32;
 680         break;
 681     case VT_UI4:
 682         *val = V_UI4( var );
 683         *type = CIM_UINT32;
 684         break;
 685     case VT_NULL:
 686         *val = 0;
 687         break;
 688     default:
 689         ERR("unhandled type %u\n", V_VT( var ));
 690         return WBEM_E_FAILED;
 691     }
 692     return S_OK;
 693 }
 694
 695 HRESULT put_propval( const struct view *view, UINT index, const WCHAR *name, VARIANT *var, CIMTYPE type )
 696 {
 697     HRESULT hr;
 698     UINT column, row = view->result[index];
 699     LONGLONG val;
 700
 701     hr = get_column_index( view->table, name, &column );
 702     if (hr != S_OK)
 703     {
 704         FIXME("no support for creating new properties\n");
 705         return WBEM_E_FAILED;
 706     }
 707     if (is_method( view->table, column ) || !(view->table->columns[column].type & COL_FLAG_DYNAMIC))
 708         return WBEM_E_FAILED;
 709
 710     hr = variant_to_longlong( var, &val, &type );
 711     if (hr != S_OK) return hr;
 712
 713     return set_value( view->table, row, column, val, type );
 714 }
 715
 716 HRESULT get_properties( const struct view *view, SAFEARRAY **props )
 717 {
 718     SAFEARRAY *sa;
 719     BSTR str;
 720     LONG i;
 721     UINT num_props = count_properties( view );
 722
 723     if (!(sa = SafeArrayCreateVector( VT_BSTR, 0, num_props ))) return E_OUTOFMEMORY;
 724
 725     for (i = 0; i < view->table->num_cols; i++)
 726     {
 727         if (is_method( view->table, i )) continue;
 728
 729         str = SysAllocString( view->table->columns[i].name );
 730         if (!str || SafeArrayPutElement( sa, &i, str ) != S_OK)
 731         {
 732             SysFreeString( str );
 733             SafeArrayDestroy( sa );
 734             return E_OUTOFMEMORY;
 735         }
 736     }
 737     *props = sa;
 738     return S_OK;
 739 }