src/core/memstore_expr.c

   1 /*
   2  * SysDB - src/core/memstore_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 arithmetic and logical expressions for in-memory
  30  * stores.
  31  */
  32
  33 #if HAVE_CONFIG_H
  34 #       include "config.h"
  35 #endif /* HAVE_CONFIG_H */
  36
  37 #include "sysdb.h"
  38 #include "core/memstore-private.h"
  39 #include "core/data.h"
  40 #include "core/object.h"
  41
  42 #include <assert.h>
  43 #include <stdbool.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46
  47 /*
  48  * private data types
  49  */
  50
  51 /* iterate through either a list of child nodes or arrays */
  52 struct sdb_memstore_expr_iter {
  53         sdb_memstore_obj_t *obj;
  54         sdb_memstore_expr_t *expr;
  55
  56         sdb_avltree_iter_t *tree;
  57
  58         sdb_data_t array;
  59         size_t array_idx;
  60         bool free_array;
  61
  62         sdb_memstore_matcher_t *filter;
  63 };
  64
  65 /*
  66  * private types
  67  */
  68
  69 static int
  70 expr_init(sdb_object_t *obj, va_list ap)
  71 {
  72         int type = va_arg(ap, int);
  73         sdb_memstore_expr_t *left  = va_arg(ap, sdb_memstore_expr_t *);
  74         sdb_memstore_expr_t *right = va_arg(ap, sdb_memstore_expr_t *);
  75         const sdb_data_t *value = va_arg(ap, const sdb_data_t *);
  76
  77         sdb_memstore_expr_t *expr = SDB_MEMSTORE_EXPR(obj);
  78
  79         if (type <= 0) {
  80                 if (! value)
  81                         return -1;
  82                 if ((type == TYPED_EXPR) && (! left))
  83                         return -1;
  84         } else {
  85                 if (value)
  86                         return -1;
  87                 if ((! left) || (! right))
  88                         return -1;
  89         }
  90
  91         if (value)
  92                 expr->data = *value;
  93
  94         sdb_object_ref(SDB_OBJ(left));
  95         sdb_object_ref(SDB_OBJ(right));
  96
  97         expr->type  = type;
  98         expr->left  = left;
  99         expr->right = right;
 100
 101         /* unknown for now */
 102         expr->data_type = -1;
 103         return 0;
 104 } /* expr_init */
 105
 106 static void
 107 expr_destroy(sdb_object_t *obj)
 108 {
 109         sdb_memstore_expr_t *expr = SDB_MEMSTORE_EXPR(obj);
 110         sdb_object_deref(SDB_OBJ(expr->left));
 111         sdb_object_deref(SDB_OBJ(expr->right));
 112
 113         if (expr->data.type)
 114                 sdb_data_free_datum(&expr->data);
 115 } /* expr_destroy */
 116
 117 static sdb_type_t expr_type = {
 118         /* size = */ sizeof(sdb_memstore_expr_t),
 119         /* init = */ expr_init,
 120         /* destroy = */ expr_destroy,
 121 };
 122
 123 /*
 124  * public API
 125  */
 126
 127 sdb_memstore_expr_t *
 128 sdb_memstore_expr_create(int op, sdb_memstore_expr_t *left, sdb_memstore_expr_t *right)
 129 {
 130         sdb_data_t value = SDB_DATA_INIT;
 131         sdb_memstore_expr_t *e;
 132
 133         if ((op < 0) || (SDB_DATA_CONCAT < op) || (! left) || (! right))
 134                 return NULL;
 135
 136         if (left->type || right->type) {
 137                 e = SDB_MEMSTORE_EXPR(sdb_object_create("memstore-expr", expr_type,
 138                                         op, left, right, NULL));
 139                 e->data_type = sdb_data_expr_type(op, left->type, right->type);
 140                 return e;
 141         }
 142         /* else: both expressions are constant values; evaluate now */
 143
 144         if (sdb_data_expr_eval(op, &left->data, &right->data, &value))
 145                 return NULL;
 146         e = SDB_MEMSTORE_EXPR(sdb_object_create("memstore-constvalue", expr_type,
 147                                 0, NULL, NULL, &value));
 148         e->data_type = value.type;
 149         return e;
 150 } /* sdb_memstore_expr_create */
 151
 152 sdb_memstore_expr_t *
 153 sdb_memstore_expr_typed(int typ, sdb_memstore_expr_t *expr)
 154 {
 155         sdb_data_t value = { SDB_TYPE_INTEGER, { .integer = typ } };
 156         sdb_memstore_expr_t *e;
 157
 158         if ((typ < SDB_HOST) || (SDB_ATTRIBUTE < typ))
 159                 return NULL;
 160
 161         e = SDB_MEMSTORE_EXPR(sdb_object_create("memstore-typedexpr", expr_type,
 162                                 TYPED_EXPR, expr, NULL, &value));
 163         e->data_type = expr->data_type;
 164         return e;
 165 } /* sdb_memstore_expr_typed */
 166
 167 sdb_memstore_expr_t *
 168 sdb_memstore_expr_fieldvalue(int field)
 169 {
 170         sdb_data_t value = { SDB_TYPE_INTEGER, { .integer = field } };
 171         sdb_memstore_expr_t *e;
 172
 173         if ((field < SDB_FIELD_NAME) || (SDB_FIELD_TIMESERIES < field))
 174                 return NULL;
 175         e = SDB_MEMSTORE_EXPR(sdb_object_create("memstore-fieldvalue", expr_type,
 176                                 FIELD_VALUE, NULL, NULL, &value));
 177         e->data_type = SDB_FIELD_TYPE(field);
 178         return e;
 179 } /* sdb_memstore_expr_fieldvalue */
 180
 181 sdb_memstore_expr_t *
 182 sdb_memstore_expr_attrvalue(const char *name)
 183 {
 184         sdb_data_t value = { SDB_TYPE_STRING, { .string = NULL} };
 185         sdb_memstore_expr_t *expr;
 186
 187         value.data.string = strdup(name);
 188         if (! value.data.string)
 189                 return NULL;
 190
 191         expr = SDB_MEMSTORE_EXPR(sdb_object_create("memstore-attrvalue", expr_type,
 192                                 ATTR_VALUE, NULL, NULL, &value));
 193         if (! expr)
 194                 free(value.data.string);
 195         expr->data_type = -1;
 196         return expr;
 197 } /* sdb_memstore_expr_attrvalue */
 198
 199 sdb_memstore_expr_t *
 200 sdb_memstore_expr_constvalue(const sdb_data_t *value)
 201 {
 202         sdb_data_t data = SDB_DATA_INIT;
 203         sdb_memstore_expr_t *e;
 204
 205         if (sdb_data_copy(&data, value))
 206                 return NULL;
 207         e = SDB_MEMSTORE_EXPR(sdb_object_create("memstore-constvalue", expr_type,
 208                                 0, NULL, NULL, &data));
 209         e->data_type = data.type;
 210         return e;
 211 } /* sdb_memstore_expr_constvalue */
 212
 213 int
 214 sdb_memstore_expr_eval(sdb_memstore_expr_t *expr, sdb_memstore_obj_t *obj,
 215                 sdb_data_t *res, sdb_memstore_matcher_t *filter)
 216 {
 217         sdb_data_t v1 = SDB_DATA_INIT, v2 = SDB_DATA_INIT;
 218         int status = 0;
 219
 220         if ((! expr) || (! res))
 221                 return -1;
 222
 223         if (filter && obj && (! sdb_memstore_matcher_matches(filter, obj, NULL)))
 224                 obj = NULL; /* this object does not exist */
 225
 226         if (! expr->type)
 227                 return sdb_data_copy(res, &expr->data);
 228         else if (expr->type == FIELD_VALUE)
 229                 return sdb_memstore_get_field(obj, (int)expr->data.data.integer, res);
 230         else if (expr->type == ATTR_VALUE) {
 231                 status = sdb_memstore_get_attr(obj, expr->data.data.string, res, filter);
 232                 if ((status < 0) && obj) {
 233                         /* attribute does not exist => NULL */
 234                         status = 0;
 235                         res->type = SDB_TYPE_STRING;
 236                         res->data.string = NULL;
 237                 }
 238                 return status;
 239         }
 240         else if (expr->type == TYPED_EXPR) {
 241                 int typ = (int)expr->data.data.integer;
 242                 if (typ != obj->type) {
 243                         /* we support self-references and { service, metric } -> host */
 244                         if ((typ != SDB_HOST)
 245                                         || ((obj->type != SDB_SERVICE)
 246                                                 && (obj->type != SDB_METRIC)))
 247                                 return -1;
 248                         obj = obj->parent;
 249                 }
 250                 return sdb_memstore_expr_eval(expr->left, obj, res, filter);
 251         }
 252
 253         if (sdb_memstore_expr_eval(expr->left, obj, &v1, filter))
 254                 return -1;
 255         if (sdb_memstore_expr_eval(expr->right, obj, &v2, filter)) {
 256                 sdb_data_free_datum(&v1);
 257                 return -1;
 258         }
 259
 260         if (sdb_data_expr_eval(expr->type, &v1, &v2, res))
 261                 status = -1;
 262         sdb_data_free_datum(&v1);
 263         sdb_data_free_datum(&v2);
 264         return status;
 265 } /* sdb_memstore_expr_eval */
 266
 267 sdb_memstore_expr_iter_t *
 268 sdb_memstore_expr_iter(sdb_memstore_expr_t *expr, sdb_memstore_obj_t *obj,
 269                 sdb_memstore_matcher_t *filter)
 270 {
 271         sdb_memstore_expr_iter_t *iter;
 272         sdb_avltree_iter_t *tree = NULL;
 273         sdb_data_t array = SDB_DATA_INIT;
 274         bool free_array = 0;
 275
 276         if (! expr)
 277                 return NULL;
 278
 279         while (expr->type == TYPED_EXPR) {
 280                 int type = (int)expr->data.data.integer;
 281
 282                 if (obj->type == type) {
 283                         /* self reference */
 284                 }
 285                 else if ((type == SDB_HOST)
 286                                 && ((obj->type == SDB_SERVICE)
 287                                         || (obj->type == SDB_METRIC))) {
 288                         /* reference to parent host */
 289                         obj = obj->parent;
 290                 }
 291                 else
 292                         break;
 293                 expr = expr->left;
 294         }
 295
 296         if (expr->type == TYPED_EXPR) {
 297                 if (! obj)
 298                         return NULL;
 299                 if (obj->type == SDB_HOST) {
 300                         if (expr->data.data.integer == SDB_SERVICE)
 301                                 tree = sdb_avltree_get_iter(HOST(obj)->services);
 302                         else if (expr->data.data.integer == SDB_METRIC)
 303                                 tree = sdb_avltree_get_iter(HOST(obj)->metrics);
 304                         else if (expr->data.data.integer == SDB_ATTRIBUTE)
 305                                 tree = sdb_avltree_get_iter(HOST(obj)->attributes);
 306                 }
 307                 else if (obj->type == SDB_SERVICE) {
 308                         if (expr->data.data.integer == SDB_ATTRIBUTE)
 309                                 tree = sdb_avltree_get_iter(SVC(obj)->attributes);
 310                 }
 311                 else if (obj->type == SDB_METRIC) {
 312                         if (expr->data.data.integer == SDB_ATTRIBUTE)
 313                                 tree = sdb_avltree_get_iter(METRIC(obj)->attributes);
 314                 }
 315         }
 316         else if (expr->type == FIELD_VALUE) {
 317                 if (! obj)
 318                         return NULL;
 319                 if (expr->data.data.integer == SDB_FIELD_BACKEND) {
 320                         /* while scanning the store, we hold a read lock, so it's safe to
 321                          * access the data without copying */
 322                         array.type = SDB_TYPE_ARRAY | SDB_TYPE_STRING;
 323                         array.data.array.length = obj->backends_num;
 324                         array.data.array.values = obj->backends;
 325                 }
 326         }
 327         else if (! expr->type) {
 328                 if (expr->data.type & SDB_TYPE_ARRAY)
 329                         array = expr->data;
 330         }
 331         else {
 332                 sdb_data_t value = SDB_DATA_INIT;
 333                 if (sdb_memstore_expr_eval(expr, obj, &value, filter))
 334                         return NULL;
 335                 if (! (value.type & SDB_TYPE_ARRAY)) {
 336                         sdb_data_free_datum(&value);
 337                         return NULL;
 338                 }
 339                 array = value;
 340                 free_array = 1;
 341         }
 342
 343         if ((! tree) && (array.type == SDB_TYPE_NULL))
 344                 return NULL;
 345
 346         iter = calloc(1, sizeof(*iter));
 347         if (! iter) {
 348                 if (free_array)
 349                         sdb_data_free_datum(&array);
 350                 return NULL;
 351         }
 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->free_array = free_array;
 362         iter->filter = filter;
 363         return iter;
 364 } /* sdb_memstore_expr_iter */
 365
 366 void
 367 sdb_memstore_expr_iter_destroy(sdb_memstore_expr_iter_t *iter)
 368 {
 369         sdb_data_t null = SDB_DATA_INIT;
 370
 371         if (! iter)
 372                 return;
 373
 374         if (iter->tree)
 375                 sdb_avltree_iter_destroy(iter->tree);
 376         iter->tree = NULL;
 377
 378         if (iter->free_array)
 379                 sdb_data_free_datum(&iter->array);
 380         iter->array = null;
 381         iter->array_idx = 0;
 382
 383         sdb_object_deref(SDB_OBJ(iter->obj));
 384         sdb_object_deref(SDB_OBJ(iter->expr));
 385         sdb_object_deref(SDB_OBJ(iter->filter));
 386         free(iter);
 387 } /* sdb_memstore_expr_iter_destroy */
 388
 389 bool
 390 sdb_memstore_expr_iter_has_next(sdb_memstore_expr_iter_t *iter)
 391 {
 392         if (! iter)
 393                 return 0;
 394
 395         if (iter->tree) {
 396                 /* this function may be called before get_next,
 397                  * so we'll have to apply filters here as well */
 398                 if (iter->filter) {
 399                         sdb_memstore_obj_t *child;
 400                         while ((child = STORE_OBJ(sdb_avltree_iter_peek_next(iter->tree)))) {
 401                                 if (sdb_memstore_matcher_matches(iter->filter, child, NULL))
 402                                         break;
 403                                 (void)sdb_avltree_iter_get_next(iter->tree);
 404                         }
 405                 }
 406
 407                 return sdb_avltree_iter_has_next(iter->tree);
 408         }
 409
 410         return iter->array_idx < iter->array.data.array.length;
 411 } /* sdb_memstore_expr_iter_has_next */
 412
 413 sdb_data_t
 414 sdb_memstore_expr_iter_get_next(sdb_memstore_expr_iter_t *iter)
 415 {
 416         sdb_data_t null = SDB_DATA_INIT;
 417         sdb_data_t ret = SDB_DATA_INIT;
 418         sdb_data_t tmp = SDB_DATA_INIT;
 419
 420         if (! iter)
 421                 return null;
 422
 423         if (iter->tree) {
 424                 sdb_memstore_obj_t *child;
 425
 426                 while (42) {
 427                         child = STORE_OBJ(sdb_avltree_iter_get_next(iter->tree));
 428                         if (! child)
 429                                 break;
 430                         if (iter->filter
 431                                         && (! sdb_memstore_matcher_matches(iter->filter, child, NULL)))
 432                                 continue;
 433
 434                         if (sdb_memstore_expr_eval(iter->expr, child, &ret, iter->filter))
 435                                 return null;
 436                         break;
 437                 }
 438
 439                 /* Skip over any filtered objects */
 440                 if (iter->filter) {
 441                         while ((child = STORE_OBJ(sdb_avltree_iter_peek_next(iter->tree)))) {
 442                                 if (sdb_memstore_matcher_matches(iter->filter, child, NULL))
 443                                         break;
 444                                 (void)sdb_avltree_iter_get_next(iter->tree);
 445                         }
 446                 }
 447
 448                 return ret;
 449         }
 450
 451         if (iter->array_idx >= iter->array.data.array.length)
 452                 return null;
 453
 454         ++iter->array_idx;
 455         if (sdb_data_array_get(&iter->array, iter->array_idx - 1, &ret))
 456                 return null;
 457         if (sdb_data_copy(&tmp, &ret))
 458                 return null;
 459         ret = tmp;
 460         return ret;
 461 } /* sdb_memstore_expr_iter_get_next */
 462
 463 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 464