src/core/store_expr.c

   1 /*
   2  * SysDB - src/core/store_expr.c
   3  * Copyright (C) 2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  17  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
  19  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /*
  29  * This module implements expressions which may be executed in the store.
  30  */
  31
  32 #if HAVE_CONFIG_H
  33 #       include "config.h"
  34 #endif /* HAVE_CONFIG_H */
  35
  36 #include "sysdb.h"
  37 #include "core/store-private.h"
  38 #include "core/data.h"
  39 #include "core/object.h"
  40
  41 #include <assert.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 /*
  46  * private data types
  47  */
  48
  49 /* iterate through either a list of child nodes or arrays */
  50 struct sdb_store_expr_iter {
  51         sdb_store_obj_t *obj;
  52         sdb_store_expr_t *expr;
  53
  54         sdb_avltree_iter_t *tree;
  55
  56         sdb_data_t array;
  57         size_t array_idx;
  58
  59         sdb_store_matcher_t *filter;
  60 };
  61
  62 /*
  63  * private types
  64  */
  65
  66 static int
  67 expr_init(sdb_object_t *obj, va_list ap)
  68 {
  69         int type = va_arg(ap, int);
  70         sdb_store_expr_t *left  = va_arg(ap, sdb_store_expr_t *);
  71         sdb_store_expr_t *right = va_arg(ap, sdb_store_expr_t *);
  72         const sdb_data_t *value = va_arg(ap, const sdb_data_t *);
  73
  74         sdb_store_expr_t *expr = SDB_STORE_EXPR(obj);
  75
  76         if (type <= 0) {
  77                 if (! value)
  78                         return -1;
  79                 if ((type == TYPED_EXPR) && (! left))
  80                         return -1;
  81         } else {
  82                 if (value)
  83                         return -1;
  84                 if ((! left) || (! right))
  85                         return -1;
  86         }
  87
  88         if (value)
  89                 expr->data = *value;
  90
  91         sdb_object_ref(SDB_OBJ(left));
  92         sdb_object_ref(SDB_OBJ(right));
  93
  94         expr->type  = type;
  95         expr->left  = left;
  96         expr->right = right;
  97
  98         /* unknown for now */
  99         expr->data_type = -1;
 100         return 0;
 101 } /* expr_init */
 102
 103 static void
 104 expr_destroy(sdb_object_t *obj)
 105 {
 106         sdb_store_expr_t *expr = SDB_STORE_EXPR(obj);
 107         sdb_object_deref(SDB_OBJ(expr->left));
 108         sdb_object_deref(SDB_OBJ(expr->right));
 109
 110         if (expr->data.type)
 111                 sdb_data_free_datum(&expr->data);
 112 } /* expr_destroy */
 113
 114 static sdb_type_t expr_type = {
 115         /* size = */ sizeof(sdb_store_expr_t),
 116         /* init = */ expr_init,
 117         /* destroy = */ expr_destroy,
 118 };
 119
 120 /*
 121  * public API
 122  */
 123
 124 sdb_store_expr_t *
 125 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right)
 126 {
 127         sdb_data_t value = SDB_DATA_INIT;
 128         sdb_store_expr_t *e;
 129
 130         if ((op < 0) || (SDB_DATA_CONCAT < op) || (! left) || (! right))
 131                 return NULL;
 132
 133         if (left->type || right->type) {
 134                 e = SDB_STORE_EXPR(sdb_object_create("store-expr", expr_type,
 135                                         op, left, right, NULL));
 136                 e->data_type = sdb_data_expr_type(op, left->type, right->type);
 137                 return e;
 138         }
 139         /* else: both expressions are constant values; evaluate now */
 140
 141         if (sdb_data_expr_eval(op, &left->data, &right->data, &value))
 142                 return NULL;
 143         e = SDB_STORE_EXPR(sdb_object_create("store-constvalue", expr_type,
 144                                 0, NULL, NULL, &value));
 145         e->data_type = value.type;
 146         return e;
 147 } /* sdb_store_expr_create */
 148
 149 sdb_store_expr_t *
 150 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr)
 151 {
 152         sdb_data_t value = { SDB_TYPE_INTEGER, { .integer = typ } };
 153         sdb_store_expr_t *e;
 154
 155         if ((typ < SDB_HOST) || (SDB_ATTRIBUTE < typ))
 156                 return NULL;
 157
 158         e = SDB_STORE_EXPR(sdb_object_create("store-typedexpr", expr_type,
 159                                 TYPED_EXPR, expr, NULL, &value));
 160         e->data_type = expr->data_type;
 161         return e;
 162 } /* sdb_store_expr_typed */
 163
 164 sdb_store_expr_t *
 165 sdb_store_expr_fieldvalue(int field)
 166 {
 167         sdb_data_t value = { SDB_TYPE_INTEGER, { .integer = field } };
 168         sdb_store_expr_t *e;
 169
 170         if ((field < SDB_FIELD_NAME) || (SDB_FIELD_BACKEND < field))
 171                 return NULL;
 172         e = SDB_STORE_EXPR(sdb_object_create("store-fieldvalue", expr_type,
 173                                 FIELD_VALUE, NULL, NULL, &value));
 174         e->data_type = SDB_FIELD_TYPE(field);
 175         return e;
 176 } /* sdb_store_expr_fieldvalue */
 177
 178 sdb_store_expr_t *
 179 sdb_store_expr_attrvalue(const char *name)
 180 {
 181         sdb_data_t value = { SDB_TYPE_STRING, { .string = NULL} };
 182         sdb_store_expr_t *expr;
 183
 184         value.data.string = strdup(name);
 185         if (! value.data.string)
 186                 return NULL;
 187
 188         expr = SDB_STORE_EXPR(sdb_object_create("store-attrvalue", expr_type,
 189                                 ATTR_VALUE, NULL, NULL, &value));
 190         if (! expr)
 191                 free(value.data.string);
 192         expr->data_type = -1;
 193         return expr;
 194 } /* sdb_store_expr_attrvalue */
 195
 196 sdb_store_expr_t *
 197 sdb_store_expr_constvalue(const sdb_data_t *value)
 198 {
 199         sdb_data_t data = SDB_DATA_INIT;
 200         sdb_store_expr_t *e;
 201
 202         if (sdb_data_copy(&data, value))
 203                 return NULL;
 204         e = SDB_STORE_EXPR(sdb_object_create("store-constvalue", expr_type,
 205                                 0, NULL, NULL, &data));
 206         e->data_type = data.type;
 207         return e;
 208 } /* sdb_store_expr_constvalue */
 209
 210 int
 211 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
 212                 sdb_data_t *res, sdb_store_matcher_t *filter)
 213 {
 214         sdb_data_t v1 = SDB_DATA_INIT, v2 = SDB_DATA_INIT;
 215         int status = 0;
 216
 217         if ((! expr) || (! res))
 218                 return -1;
 219
 220         if (filter && obj && (! sdb_store_matcher_matches(filter, obj, NULL)))
 221                 obj = NULL; /* this object does not exist */
 222
 223         if (! expr->type)
 224                 return sdb_data_copy(res, &expr->data);
 225         else if (expr->type == FIELD_VALUE)
 226                 return sdb_store_get_field(obj, (int)expr->data.data.integer, res);
 227         else if (expr->type == ATTR_VALUE) {
 228                 status = sdb_store_get_attr(obj, expr->data.data.string, res, filter);
 229                 if ((status < 0) && obj) {
 230                         /* attribute does not exist => NULL */
 231                         status = 0;
 232                         res->type = SDB_TYPE_STRING;
 233                         res->data.string = NULL;
 234                 }
 235                 return status;
 236         }
 237         else if (expr->type == TYPED_EXPR) {
 238                 int typ = (int)expr->data.data.integer;
 239                 if (typ != obj->type) {
 240                         /* we support self-references and { service, metric } -> host */
 241                         if ((typ != SDB_HOST)
 242                                         || ((obj->type != SDB_SERVICE)
 243                                                 && (obj->type != SDB_METRIC)))
 244                                 return -1;
 245                         obj = obj->parent;
 246                 }
 247                 return sdb_store_expr_eval(expr->left, obj, res, filter);
 248         }
 249
 250         if (sdb_store_expr_eval(expr->left, obj, &v1, filter))
 251                 return -1;
 252         if (sdb_store_expr_eval(expr->right, obj, &v2, filter)) {
 253                 sdb_data_free_datum(&v1);
 254                 return -1;
 255         }
 256
 257         if (sdb_data_expr_eval(expr->type, &v1, &v2, res))
 258                 status = -1;
 259         sdb_data_free_datum(&v1);
 260         sdb_data_free_datum(&v2);
 261         return status;
 262 } /* sdb_store_expr_eval */
 263
 264 bool
 265 sdb_store_expr_iterable(sdb_store_expr_t *expr, int context)
 266 {
 267         if (expr->type == TYPED_EXPR) {
 268                 if ((context != SDB_HOST) && (context != SDB_SERVICE)
 269                                 && (context != SDB_METRIC))
 270                         return 0;
 271                 if (context == expr->data.data.integer)
 272                         return 0;
 273                 if ((expr->data.data.integer != SDB_SERVICE)
 274                                 && (expr->data.data.integer != SDB_METRIC)
 275                                 && (expr->data.data.integer != SDB_ATTRIBUTE))
 276                         return 0;
 277                 if ((context == SDB_SERVICE)
 278                                 && (expr->data.data.integer == SDB_METRIC))
 279                         return 0;
 280                 else if ((context == SDB_METRIC)
 281                                 && (expr->data.data.integer == SDB_SERVICE))
 282                         return 0;
 283                 return 1;
 284         }
 285         else if (expr->type == FIELD_VALUE) {
 286                 if ((context != SDB_HOST) && (context != SDB_SERVICE)
 287                                 && (context != SDB_METRIC) && (context != SDB_ATTRIBUTE))
 288                         return 0;
 289                 return expr->data.data.integer == SDB_FIELD_BACKEND;
 290         }
 291         else if (! expr->type) {
 292                 return !!(expr->data.type & SDB_TYPE_ARRAY);
 293         }
 294         return 0;
 295 } /* sdb_store_expr_iterable */
 296
 297 sdb_store_expr_iter_t *
 298 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
 299                 sdb_store_matcher_t *filter)
 300 {
 301         sdb_store_expr_iter_t *iter;
 302         sdb_avltree_iter_t *tree = NULL;
 303         sdb_data_t array = SDB_DATA_INIT;
 304
 305         if (! expr)
 306                 return NULL;
 307
 308         if (expr->type == TYPED_EXPR) {
 309                 if (! obj)
 310                         return NULL;
 311                 if (obj->type == SDB_HOST) {
 312                         if (expr->data.data.integer == SDB_SERVICE)
 313                                 tree = sdb_avltree_get_iter(HOST(obj)->services);
 314                         else if (expr->data.data.integer == SDB_METRIC)
 315                                 tree = sdb_avltree_get_iter(HOST(obj)->metrics);
 316                         else if (expr->data.data.integer == SDB_ATTRIBUTE)
 317                                 tree = sdb_avltree_get_iter(HOST(obj)->attributes);
 318                 }
 319                 else if (obj->type == SDB_SERVICE) {
 320                         if (expr->data.data.integer == SDB_ATTRIBUTE)
 321                                 tree = sdb_avltree_get_iter(SVC(obj)->attributes);
 322                 }
 323                 else if (obj->type == SDB_METRIC) {
 324                         if (expr->data.data.integer == SDB_ATTRIBUTE)
 325                                 tree = sdb_avltree_get_iter(METRIC(obj)->attributes);
 326                 }
 327         }
 328         else if (expr->type == FIELD_VALUE) {
 329                 if (! obj)
 330                         return NULL;
 331                 if (expr->data.data.integer == SDB_FIELD_BACKEND) {
 332                         /* while scanning the store, we hold a read lock, so it's safe to
 333                          * access the data without copying */
 334                         array.type = SDB_TYPE_ARRAY | SDB_TYPE_STRING;
 335                         array.data.array.length = obj->backends_num;
 336                         array.data.array.values = obj->backends;
 337                 }
 338         }
 339         else if (! expr->type) {
 340                 if (expr->data.type & SDB_TYPE_ARRAY)
 341                         array = expr->data;
 342         }
 343         else
 344                 return NULL;
 345
 346         if ((! tree) && (array.type == SDB_TYPE_NULL))
 347                 return NULL;
 348
 349         iter = calloc(1, sizeof(*iter));
 350         if (! iter)
 351                 return NULL;
 352
 353         sdb_object_ref(SDB_OBJ(obj));
 354         sdb_object_ref(SDB_OBJ(expr));
 355         sdb_object_ref(SDB_OBJ(filter));
 356
 357         iter->obj = obj;
 358         iter->expr = expr;
 359         iter->tree = tree;
 360         iter->array = array;
 361         iter->filter = filter;
 362         return iter;
 363 } /* sdb_store_expr_iter */
 364
 365 void
 366 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter)
 367 {
 368         sdb_data_t null = SDB_DATA_INIT;
 369
 370         if (! iter)
 371                 return;
 372
 373         if (iter->tree)
 374                 sdb_avltree_iter_destroy(iter->tree);
 375         iter->tree = NULL;
 376
 377         iter->array = null;
 378         iter->array_idx = 0;
 379
 380         sdb_object_deref(SDB_OBJ(iter->obj));
 381         sdb_object_deref(SDB_OBJ(iter->expr));
 382         sdb_object_deref(SDB_OBJ(iter->filter));
 383         free(iter);
 384 } /* sdb_store_expr_iter_destroy */
 385
 386 bool
 387 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter)
 388 {
 389         if (! iter)
 390                 return 0;
 391
 392         if (iter->tree) {
 393                 /* this function may be called before get_next,
 394                  * so we'll have to apply filters here as well */
 395                 if (iter->filter) {
 396                         sdb_store_obj_t *child;
 397                         while ((child = STORE_OBJ(sdb_avltree_iter_peek_next(iter->tree)))) {
 398                                 if (sdb_store_matcher_matches(iter->filter, child, NULL))
 399                                         break;
 400                                 (void)sdb_avltree_iter_get_next(iter->tree);
 401                         }
 402                 }
 403
 404                 return sdb_avltree_iter_has_next(iter->tree);
 405         }
 406
 407         return iter->array_idx < iter->array.data.array.length;
 408 } /* sdb_store_expr_iter_has_next */
 409
 410 sdb_data_t
 411 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter)
 412 {
 413         sdb_data_t null = SDB_DATA_INIT;
 414         sdb_data_t ret = SDB_DATA_INIT;
 415         sdb_data_t tmp = SDB_DATA_INIT;
 416
 417         if (! iter)
 418                 return null;
 419
 420         if (iter->tree) {
 421                 sdb_store_obj_t *child;
 422
 423                 while (42) {
 424                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter->tree));
 425                         if (! child)
 426                                 break;
 427                         if (iter->filter
 428                                         && (! sdb_store_matcher_matches(iter->filter, child, NULL)))
 429                                 continue;
 430
 431                         if (sdb_store_expr_eval(iter->expr, child, &ret, iter->filter))
 432                                 return null;
 433                         break;
 434                 }
 435
 436                 /* Skip over any filtered objects */
 437                 if (iter->filter) {
 438                         while ((child = STORE_OBJ(sdb_avltree_iter_peek_next(iter->tree)))) {
 439                                 if (sdb_store_matcher_matches(iter->filter, child, NULL))
 440                                         break;
 441                                 (void)sdb_avltree_iter_get_next(iter->tree);
 442                         }
 443                 }
 444
 445                 return ret;
 446         }
 447
 448         if (iter->array_idx >= iter->array.data.array.length)
 449                 return null;
 450
 451         ++iter->array_idx;
 452         if (sdb_data_array_get(&iter->array, iter->array_idx - 1, &ret))
 453                 return null;
 454         if (sdb_data_copy(&tmp, &ret))
 455                 return null;
 456         ret = tmp;
 457         return ret;
 458 } /* sdb_store_expr_iter_get_next */
 459
 460 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 461