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 <stdbool.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46 /*
  47  * private data types
  48  */
  49
  50 /* iterate through either a list of child nodes or arrays */
  51 struct sdb_memstore_expr_iter {
  52         sdb_memstore_obj_t *obj;
  53         sdb_memstore_expr_t *expr;
  54
  55         sdb_avltree_iter_t *tree;
  56
  57         sdb_data_t array;
  58         size_t array_idx;
  59         bool free_array;
  60
  61         sdb_memstore_matcher_t *filter;
  62 };
  63
  64 /*
  65  * private types
  66  */
  67
  68 static int
  69 expr_init(sdb_object_t *obj, va_list ap)
  70 {
  71         int type = va_arg(ap, int);
  72         sdb_memstore_expr_t *left  = va_arg(ap, sdb_memstore_expr_t *);
  73         sdb_memstore_expr_t *right = va_arg(ap, sdb_memstore_expr_t *);
  74         const sdb_data_t *value = va_arg(ap, const sdb_data_t *);
  75
  76         sdb_memstore_expr_t *expr = SDB_MEMSTORE_EXPR(obj);
  77
  78         if (type <= 0) {
  79                 if (! value)
  80                         return -1;
  81                 if ((type == TYPED_EXPR) && (! left))
  82                         return -1;
  83         } else {
  84                 if (value)
  85                         return -1;
  86                 if ((! left) || (! right))
  87                         return -1;
  88         }
  89
  90         if (value)
  91                 expr->data = *value;
  92
  93         sdb_object_ref(SDB_OBJ(left));
  94         sdb_object_ref(SDB_OBJ(right));
  95
  96         expr->type  = type;
  97         expr->left  = left;
  98         expr->right = right;
  99
 100         /* unknown for now */
 101         expr->data_type = -1;
 102         return 0;
 103 } /* expr_init */
 104
 105 static void
 106 expr_destroy(sdb_object_t *obj)
 107 {
 108         sdb_memstore_expr_t *expr = SDB_MEMSTORE_EXPR(obj);
 109         sdb_object_deref(SDB_OBJ(expr->left));
 110         sdb_object_deref(SDB_OBJ(expr->right));
 111
 112         if (expr->data.type)
 113                 sdb_data_free_datum(&expr->data);
 114 } /* expr_destroy */
 115
 116 static sdb_type_t expr_type = {
 117         /* size = */ sizeof(sdb_memstore_expr_t),
 118         /* init = */ expr_init,
 119         /* destroy = */ expr_destroy,
 120 };
 121
 122 /*
 123  * public API
 124  */
 125
 126 sdb_memstore_expr_t *
 127 sdb_memstore_expr_create(int op, sdb_memstore_expr_t *left, sdb_memstore_expr_t *right)
 128 {
 129         sdb_data_t value = SDB_DATA_INIT;
 130         sdb_memstore_expr_t *e;
 131
 132         if ((op < 0) || (SDB_DATA_CONCAT < op) || (! left) || (! right))
 133                 return NULL;
 134
 135         if (left->type || right->type) {
 136                 e = SDB_MEMSTORE_EXPR(sdb_object_create("store-expr", expr_type,
 137                                         op, left, right, NULL));
 138                 e->data_type = sdb_data_expr_type(op, left->type, right->type);
 139                 return e;
 140         }
 141         /* else: both expressions are constant values; evaluate now */
 142
 143         if (sdb_data_expr_eval(op, &left->data, &right->data, &value))
 144                 return NULL;
 145         e = SDB_MEMSTORE_EXPR(sdb_object_create("store-constvalue", expr_type,
 146                                 0, NULL, NULL, &value));
 147         e->data_type = value.type;
 148         return e;
 149 } /* sdb_memstore_expr_create */
 150
 151 sdb_memstore_expr_t *
 152 sdb_memstore_expr_typed(int typ, sdb_memstore_expr_t *expr)
 153 {
 154         sdb_data_t value = { SDB_TYPE_INTEGER, { .integer = typ } };
 155         sdb_memstore_expr_t *e;
 156
 157         if ((typ < SDB_HOST) || (SDB_ATTRIBUTE < typ))
 158                 return NULL;
 159
 160         e = SDB_MEMSTORE_EXPR(sdb_object_create("store-typedexpr", expr_type,
 161                                 TYPED_EXPR, expr, NULL, &value));
 162         e->data_type = expr->data_type;
 163         return e;
 164 } /* sdb_memstore_expr_typed */
 165
 166 sdb_memstore_expr_t *
 167 sdb_memstore_expr_fieldvalue(int field)
 168 {
 169         sdb_data_t value = { SDB_TYPE_INTEGER, { .integer = field } };
 170         sdb_memstore_expr_t *e;
 171
 172         if ((field < SDB_FIELD_NAME) || (SDB_FIELD_TIMESERIES < field))
 173                 return NULL;
 174         e = SDB_MEMSTORE_EXPR(sdb_object_create("store-fieldvalue", expr_type,
 175                                 FIELD_VALUE, NULL, NULL, &value));
 176         e->data_type = SDB_FIELD_TYPE(field);
 177         return e;
 178 } /* sdb_memstore_expr_fieldvalue */
 179
 180 sdb_memstore_expr_t *
 181 sdb_memstore_expr_attrvalue(const char *name)
 182 {
 183         sdb_data_t value = { SDB_TYPE_STRING, { .string = NULL} };
 184         sdb_memstore_expr_t *expr;
 185
 186         value.data.string = strdup(name);
 187         if (! value.data.string)
 188                 return NULL;
 189
 190         expr = SDB_MEMSTORE_EXPR(sdb_object_create("store-attrvalue", expr_type,
 191                                 ATTR_VALUE, NULL, NULL, &value));
 192         if (! expr)
 193                 free(value.data.string);
 194         expr->data_type = -1;
 195         return expr;
 196 } /* sdb_memstore_expr_attrvalue */
 197
 198 sdb_memstore_expr_t *
 199 sdb_memstore_expr_constvalue(const sdb_data_t *value)
 200 {
 201         sdb_data_t data = SDB_DATA_INIT;
 202         sdb_memstore_expr_t *e;
 203
 204         if (sdb_data_copy(&data, value))
 205                 return NULL;
 206         e = SDB_MEMSTORE_EXPR(sdb_object_create("store-constvalue", expr_type,
 207                                 0, NULL, NULL, &data));
 208         e->data_type = data.type;
 209         return e;
 210 } /* sdb_memstore_expr_constvalue */
 211
 212 int
 213 sdb_memstore_expr_eval(sdb_memstore_expr_t *expr, sdb_memstore_obj_t *obj,
 214                 sdb_data_t *res, sdb_memstore_matcher_t *filter)
 215 {
 216         sdb_data_t v1 = SDB_DATA_INIT, v2 = SDB_DATA_INIT;
 217         int status = 0;
 218
 219         if ((! expr) || (! res))
 220                 return -1;
 221
 222         if (filter && obj && (! sdb_memstore_matcher_matches(filter, obj, NULL)))
 223                 obj = NULL; /* this object does not exist */
 224
 225         if (! expr->type)
 226                 return sdb_data_copy(res, &expr->data);
 227         else if (expr->type == FIELD_VALUE)
 228                 return sdb_memstore_get_field(obj, (int)expr->data.data.integer, res);
 229         else if (expr->type == ATTR_VALUE) {
 230                 status = sdb_memstore_get_attr(obj, expr->data.data.string, res, filter);
 231                 if ((status < 0) && obj) {
 232                         /* attribute does not exist => NULL */
 233                         status = 0;
 234                         res->type = SDB_TYPE_STRING;
 235                         res->data.string = NULL;
 236                 }
 237                 return status;
 238         }
 239         else if (expr->type == TYPED_EXPR) {
 240                 int typ = (int)expr->data.data.integer;
 241                 if (typ != obj->type) {
 242                         /* we support self-references and { service, metric } -> host */
 243                         if ((typ != SDB_HOST)
 244                                         || ((obj->type != SDB_SERVICE)
 245                                                 && (obj->type != SDB_METRIC)))
 246                                 return -1;
 247                         obj = obj->parent;
 248                 }
 249                 return sdb_memstore_expr_eval(expr->left, obj, res, filter);
 250         }
 251
 252         if (sdb_memstore_expr_eval(expr->left, obj, &v1, filter))
 253                 return -1;
 254         if (sdb_memstore_expr_eval(expr->right, obj, &v2, filter)) {
 255                 sdb_data_free_datum(&v1);
 256                 return -1;
 257         }
 258
 259         if (sdb_data_expr_eval(expr->type, &v1, &v2, res))
 260                 status = -1;
 261         sdb_data_free_datum(&v1);
 262         sdb_data_free_datum(&v2);
 263         return status;
 264 } /* sdb_memstore_expr_eval */
 265
 266 sdb_memstore_expr_iter_t *
 267 sdb_memstore_expr_iter(sdb_memstore_expr_t *expr, sdb_memstore_obj_t *obj,
 268                 sdb_memstore_matcher_t *filter)
 269 {
 270         sdb_memstore_expr_iter_t *iter;
 271         sdb_avltree_iter_t *tree = NULL;
 272         sdb_data_t array = SDB_DATA_INIT;
 273         bool free_array = 0;
 274
 275         if (! expr)
 276                 return NULL;
 277
 278         while (expr->type == TYPED_EXPR) {
 279                 int type = (int)expr->data.data.integer;
 280
 281                 if (obj->type == type) {
 282                         /* self reference */
 283                 }
 284                 else if ((type == SDB_HOST)
 285                                 && ((obj->type == SDB_SERVICE)
 286                                         || (obj->type == SDB_METRIC))) {
 287                         /* reference to parent host */
 288                         obj = obj->parent;
 289                 }
 290                 else
 291                         break;
 292                 expr = expr->left;
 293         }
 294
 295         if (expr->type == TYPED_EXPR) {
 296                 if (! obj)
 297                         return NULL;
 298                 if (obj->type == SDB_HOST) {
 299                         if (expr->data.data.integer == SDB_SERVICE)
 300                                 tree = sdb_avltree_get_iter(HOST(obj)->services);
 301                         else if (expr->data.data.integer == SDB_METRIC)
 302                                 tree = sdb_avltree_get_iter(HOST(obj)->metrics);
 303                         else if (expr->data.data.integer == SDB_ATTRIBUTE)
 304                                 tree = sdb_avltree_get_iter(HOST(obj)->attributes);
 305                 }
 306                 else if (obj->type == SDB_SERVICE) {
 307                         if (expr->data.data.integer == SDB_ATTRIBUTE)
 308                                 tree = sdb_avltree_get_iter(SVC(obj)->attributes);
 309                 }
 310                 else if (obj->type == SDB_METRIC) {
 311                         if (expr->data.data.integer == SDB_ATTRIBUTE)
 312                                 tree = sdb_avltree_get_iter(METRIC(obj)->attributes);
 313                 }
 314         }
 315         else if (expr->type == FIELD_VALUE) {
 316                 if (! obj)
 317                         return NULL;
 318                 if (expr->data.data.integer == SDB_FIELD_BACKEND) {
 319                         /* while scanning the store, we hold a read lock, so it's safe to
 320                          * access the data without copying */
 321                         array.type = SDB_TYPE_ARRAY | SDB_TYPE_STRING;
 322                         array.data.array.length = obj->backends_num;
 323                         array.data.array.values = obj->backends;
 324                 }
 325         }
 326         else if (! expr->type) {
 327                 if (expr->data.type & SDB_TYPE_ARRAY)
 328                         array = expr->data;
 329         }
 330         else {
 331                 sdb_data_t value = SDB_DATA_INIT;
 332                 if (sdb_memstore_expr_eval(expr, obj, &value, filter))
 333                         return NULL;
 334                 if (! (value.type & SDB_TYPE_ARRAY)) {
 335                         sdb_data_free_datum(&value);
 336                         return NULL;
 337                 }
 338                 array = value;
 339                 free_array = 1;
 340         }
 341
 342         if ((! tree) && (array.type == SDB_TYPE_NULL))
 343                 return NULL;
 344
 345         iter = calloc(1, sizeof(*iter));
 346         if (! iter) {
 347                 if (free_array)
 348                         sdb_data_free_datum(&array);
 349                 return NULL;
 350         }
 351
 352         sdb_object_ref(SDB_OBJ(obj));
 353         sdb_object_ref(SDB_OBJ(expr));
 354         sdb_object_ref(SDB_OBJ(filter));
 355
 356         iter->obj = obj;
 357         iter->expr = expr;
 358         iter->tree = tree;
 359         iter->array = array;
 360         iter->free_array = free_array;
 361         iter->filter = filter;
 362         return iter;
 363 } /* sdb_memstore_expr_iter */
 364
 365 void
 366 sdb_memstore_expr_iter_destroy(sdb_memstore_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         if (iter->free_array)
 378                 sdb_data_free_datum(&iter->array);
 379         iter->array = null;
 380         iter->array_idx = 0;
 381
 382         sdb_object_deref(SDB_OBJ(iter->obj));
 383         sdb_object_deref(SDB_OBJ(iter->expr));
 384         sdb_object_deref(SDB_OBJ(iter->filter));
 385         free(iter);
 386 } /* sdb_memstore_expr_iter_destroy */
 387
 388 bool
 389 sdb_memstore_expr_iter_has_next(sdb_memstore_expr_iter_t *iter)
 390 {
 391         if (! iter)
 392                 return 0;
 393
 394         if (iter->tree) {
 395                 /* this function may be called before get_next,
 396                  * so we'll have to apply filters here as well */
 397                 if (iter->filter) {
 398                         sdb_memstore_obj_t *child;
 399                         while ((child = STORE_OBJ(sdb_avltree_iter_peek_next(iter->tree)))) {
 400                                 if (sdb_memstore_matcher_matches(iter->filter, child, NULL))
 401                                         break;
 402                                 (void)sdb_avltree_iter_get_next(iter->tree);
 403                         }
 404                 }
 405
 406                 return sdb_avltree_iter_has_next(iter->tree);
 407         }
 408
 409         return iter->array_idx < iter->array.data.array.length;
 410 } /* sdb_memstore_expr_iter_has_next */
 411
 412 sdb_data_t
 413 sdb_memstore_expr_iter_get_next(sdb_memstore_expr_iter_t *iter)
 414 {
 415         sdb_data_t null = SDB_DATA_INIT;
 416         sdb_data_t ret = SDB_DATA_INIT;
 417         sdb_data_t tmp = SDB_DATA_INIT;
 418
 419         if (! iter)
 420                 return null;
 421
 422         if (iter->tree) {
 423                 sdb_memstore_obj_t *child;
 424
 425                 while (42) {
 426                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter->tree));
 427                         if (! child)
 428                                 break;
 429                         if (iter->filter
 430                                         && (! sdb_memstore_matcher_matches(iter->filter, child, NULL)))
 431                                 continue;
 432
 433                         if (sdb_memstore_expr_eval(iter->expr, child, &ret, iter->filter))
 434                                 return null;
 435                         break;
 436                 }
 437
 438                 /* Skip over any filtered objects */
 439                 if (iter->filter) {
 440                         while ((child = STORE_OBJ(sdb_avltree_iter_peek_next(iter->tree)))) {
 441                                 if (sdb_memstore_matcher_matches(iter->filter, child, NULL))
 442                                         break;
 443                                 (void)sdb_avltree_iter_get_next(iter->tree);
 444                         }
 445                 }
 446
 447                 return ret;
 448         }
 449
 450         if (iter->array_idx >= iter->array.data.array.length)
 451                 return null;
 452
 453         ++iter->array_idx;
 454         if (sdb_data_array_get(&iter->array, iter->array_idx - 1, &ret))
 455                 return null;
 456         if (sdb_data_copy(&tmp, &ret))
 457                 return null;
 458         ret = tmp;
 459         return ret;
 460 } /* sdb_memstore_expr_iter_get_next */
 461
 462 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 463