e851dd9f955ee38cb3bec993fe753aa3e4f5a537
1 /*
2 * SysDB - src/include/core/store.h
3 * Copyright (C) 2012 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 */
28 #ifndef SDB_CORE_STORE_H
29 #define SDB_CORE_STORE_H 1
31 #include "sysdb.h"
32 #include "core/object.h"
33 #include "core/data.h"
34 #include "core/time.h"
35 #include "core/timeseries.h"
36 #include "parser/ast.h"
37 #include "utils/strbuf.h"
39 #include <stdbool.h>
40 #include <stdio.h>
42 #ifdef __cplusplus
43 extern "C" {
44 #endif
46 /*
47 * Store object types.
48 */
49 enum {
50 SDB_HOST = 1,
51 SDB_SERVICE,
52 SDB_METRIC,
54 SDB_ATTRIBUTE = 1 << 4,
56 /*
57 * Queryable fields of a stored object.
58 */
59 SDB_FIELD_NAME = 1 << 8, /* type: string */
60 SDB_FIELD_LAST_UPDATE, /* type: datetime */
61 SDB_FIELD_AGE, /* type: datetime */
62 SDB_FIELD_INTERVAL, /* type: datetime */
63 SDB_FIELD_BACKEND, /* type: array of strings */
64 SDB_FIELD_VALUE, /* attributes only; type: type of the value */
65 SDB_FIELD_TIMESERIES, /* metrics only; type: boolean */
66 };
67 #define SDB_STORE_TYPE_TO_NAME(t) \
68 (((t) == SDB_HOST) ? "host" \
69 : ((t) == SDB_SERVICE) ? "service" \
70 : ((t) == SDB_METRIC) ? "metric" \
71 : ((t) == SDB_ATTRIBUTE) ? "attribute" \
72 : ((t) == (SDB_ATTRIBUTE | SDB_HOST)) ? "host attribute" \
73 : ((t) == (SDB_ATTRIBUTE | SDB_SERVICE)) ? "service attribute" \
74 : ((t) == (SDB_ATTRIBUTE | SDB_METRIC)) ? "metric attribute" \
75 : "unknown")
77 #define SDB_FIELD_TO_NAME(f) \
78 (((f) == SDB_FIELD_NAME) ? "name" \
79 : ((f) == SDB_FIELD_LAST_UPDATE) ? "last-update" \
80 : ((f) == SDB_FIELD_AGE) ? "age" \
81 : ((f) == SDB_FIELD_INTERVAL) ? "interval" \
82 : ((f) == SDB_FIELD_BACKEND) ? "backend" \
83 : ((f) == SDB_FIELD_VALUE) ? "value" \
84 : ((f) == SDB_FIELD_TIMESERIES) ? "timeseries" \
85 : "unknown")
87 #define SDB_FIELD_TYPE(f) \
88 (((f) == SDB_FIELD_NAME) ? SDB_TYPE_STRING \
89 : ((f) == SDB_FIELD_LAST_UPDATE) ? SDB_TYPE_DATETIME \
90 : ((f) == SDB_FIELD_AGE) ? SDB_TYPE_DATETIME \
91 : ((f) == SDB_FIELD_INTERVAL) ? SDB_TYPE_DATETIME \
92 : ((f) == SDB_FIELD_BACKEND) ? (SDB_TYPE_ARRAY | SDB_TYPE_STRING) \
93 : ((f) == SDB_FIELD_VALUE) ? -1 /* unknown */ \
94 : ((f) == SDB_FIELD_TIMESERIES) ? SDB_TYPE_BOOLEAN \
95 : -1)
97 /*
98 * sdb_store_obj_t represents the super-class of any object stored in the
99 * database. It inherits from sdb_object_t and may safely be cast to a generic
100 * object to access its name.
101 */
102 struct sdb_store_obj;
103 typedef struct sdb_store_obj sdb_store_obj_t;
105 /*
106 * A metric store describes how to access a metric's data.
107 */
108 typedef struct {
109 const char *type;
110 const char *id;
111 } sdb_metric_store_t;
113 /*
114 * Expressions represent arithmetic expressions based on stored objects and
115 * their various attributes.
116 *
117 * An expression object inherits from sdb_object_t and, thus, may safely be
118 * cast to a generic object.
119 */
120 struct sdb_store_expr;
121 typedef struct sdb_store_expr sdb_store_expr_t;
122 #define SDB_STORE_EXPR(obj) ((sdb_store_expr_t *)(obj))
124 /*
125 * An expression iterator iterates over the values of an iterable expression
126 * (see sdb_store_expr_iterable).
127 */
128 struct sdb_store_expr_iter;
129 typedef struct sdb_store_expr_iter sdb_store_expr_iter_t;
131 /*
132 * Store matchers may be used to lookup hosts from the store based on their
133 * various attributes. Service and attribute matchers are applied to a host's
134 * services and attributes and evaluate to true if *any* service or attribute
135 * matches.
136 *
137 * A store matcher object inherits from sdb_object_t and, thus, may safely be
138 * cast to a generic object.
139 */
140 struct sdb_store_matcher;
141 typedef struct sdb_store_matcher sdb_store_matcher_t;
142 #define SDB_STORE_MATCHER(obj) ((sdb_store_matcher_t *)(obj))
144 /*
145 * A JSON formatter converts stored objects into the JSON format.
146 * See http://www.ietf.org/rfc/rfc4627.txt
147 *
148 * A JSON formatter object inherits from sdb_object_t and, thus, may safely be
149 * cast to a generic object.
150 */
151 struct sdb_store_json_formatter;
152 typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
154 /*
155 * A store writer describes the interface for plugins implementing a store.
156 *
157 * Any of the call-back functions shall return:
158 * - 0 on success
159 * - a positive value if the new entry is older than the currently stored
160 * entry (in this case, no update will happen)
161 * - a negative value on error
162 */
163 typedef struct {
164 /*
165 * store_host:
166 * Add/update a host in the store. If the host, identified by its
167 * canonicalized name, already exists, it will be updated according to the
168 * specified name and timestamp. Else, a new entry will be created in the
169 * store.
170 */
171 int (*store_host)(const char *name, sdb_time_t last_update,
172 sdb_object_t *user_data);
174 /*
175 * store_service:
176 * Add/update a service in the store. If the service, identified by its
177 * name, already exists for the specified host, it will be updated
178 * according to the specified name and timestamp. If the referenced host
179 * does not exist, an error will be reported. Else, a new entry will be
180 * created in the store.
181 */
182 int (*store_service)(const char *hostname, const char *name,
183 sdb_time_t last_update, sdb_object_t *user_data);
185 /*
186 * store_metric:
187 * Add/update a metric in the store. If the metric, identified by its
188 * name, already exists for the specified host, it will be updated
189 * according to the specified attributes. If the referenced host does not
190 * exist, an error will be reported. Else, a new entry will be created in
191 * the store.
192 */
193 int (*store_metric)(const char *hostname, const char *name,
194 sdb_metric_store_t *store, sdb_time_t last_update,
195 sdb_object_t *user_data);
197 /*
198 * store_attribute:
199 * Add/update a host's attribute in the store. If the attribute,
200 * identified by its key, already exists for the specified host, it will
201 * be updated to the specified values. If the referenced host does not
202 * exist, an error will be reported. Else, a new entry will be created in
203 * the store.
204 */
205 int (*store_attribute)(const char *hostname,
206 const char *key, const sdb_data_t *value, sdb_time_t last_update,
207 sdb_object_t *user_data);
209 /*
210 * store_service_attr:
211 * Add/update a service's attribute in the store. If the attribute,
212 * identified by its key, already exists for the specified service, it
213 * will be updated to the specified value. If the references service (for
214 * the specified host) does not exist, an error will be reported.
215 */
216 int (*store_service_attr)(const char *hostname, const char *service,
217 const char *key, const sdb_data_t *value, sdb_time_t last_update,
218 sdb_object_t *user_data);
220 /*
221 * store_metric_attr:
222 * Add/update a metric's attribute in the store. If the attribute,
223 * identified by its key, already exists for the specified metric, it will
224 * be updated to the specified value. If the references metric (for the
225 * specified host) does not exist, an error will be reported.
226 */
227 int (*store_metric_attr)(const char *hostname, const char *metric,
228 const char *key, const sdb_data_t *value, sdb_time_t last_update,
229 sdb_object_t *user_data);
230 } sdb_store_writer_t;
232 /*
233 * A store reader describes the interface to query a store implementation.
234 */
235 typedef struct {
236 /*
237 * prepare_query:
238 * Prepare the query described by 'ast' for execution.
239 */
240 sdb_object_t *(*prepare_query)(sdb_ast_node_t *ast,
241 sdb_strbuf_t *errbuf, sdb_object_t *user_data);
243 /*
244 * execute_query:
245 * Execute a previously prepared query. The callback may expect that only
246 * queries prepared by its respective prepare callback will be passed to
247 * this function.
248 *
249 * TODO: Instead of letting the executor write directly to a string buffer
250 * (which cannot easily be merged with other results), let it hand
251 * all objects to a store-writer.
252 */
253 int (*execute_query)(sdb_object_t *q,
254 sdb_strbuf_t *buf, sdb_strbuf_t *errbuf,
255 sdb_object_t *user_data);
256 } sdb_store_reader_t;
258 /*
259 * sdb_store_init:
260 * Initialize the store sub-system. This function has to be called before
261 * doing any other store operations.
262 *
263 * Returns:
264 * - 0 on success
265 * - a negative value else
266 */
267 int
268 sdb_store_init(void);
270 /*
271 * sdb_store_clear:
272 * Clear the entire store and remove all stored objects.
273 */
274 void
275 sdb_store_clear(void);
277 /*
278 * sdb_store_get_host:
279 * Query the store for a host by its (canonicalized) name.
280 *
281 * The function increments the ref count of the host object. The caller needs
282 * to deref it when no longer using it.
283 */
284 sdb_store_obj_t *
285 sdb_store_get_host(const char *name);
287 /*
288 * sdb_store_fetch_timeseries:
289 * Fetch the time-series described by the specified host's metric and
290 * serialize it as JSON into the provided string buffer.
291 *
292 * Returns:
293 * - 0 on success
294 * - a negative value else
295 */
296 int
297 sdb_store_fetch_timeseries(const char *hostname, const char *metric,
298 sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
300 /*
301 * sdb_store_get_child:
302 * Retrieve a host's child object of the specified type and name. The
303 * reference count of the child object will be incremented before returning
304 * it. The caller is responsible for releasing the object once it's no longer
305 * used.
306 *
307 * Returns:
308 * - the child object on success
309 * - NULL else
310 */
311 sdb_store_obj_t *
312 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
314 /*
315 * sdb_store_get_field:
316 * Get the value of a stored object's queryable field. The caller is
317 * responsible for freeing any dynamically allocated memory possibly stored in
318 * the returned value. If 'res' is NULL, the function will return whether the
319 * field exists.
320 *
321 * Returns:
322 * - 0 on success
323 * - a negative value else
324 */
325 int
326 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
328 /*
329 * sdb_store_get_attr:
330 * Get the value of a stored object's attribute. The caller is responsible for
331 * freeing any dynamically allocated memory possibly stored in the returned
332 * value. If 'res' is NULL, the function will return whether the attribute
333 * exists. If specified, only attributes matching the filter will be
334 * considered.
335 *
336 * Returns:
337 * - 0 if the attribute exists
338 * - a negative value else
339 */
340 int
341 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
342 sdb_store_matcher_t *filter);
344 /*
345 * Querying a store:
346 *
347 * - Query interface: A query is a formal description of an interaction with
348 * the store. It can be used, both, for read and write access. The query is
349 * described by its abstract syntax tree (AST). The parser package provides
350 * means to parse a string (SysQL) representation of the query into an AST.
351 *
352 * - Matcher / expression interface: This low-level interface provides direct
353 * control over how to access the store. It is used by the query
354 * implementation internally and can only be used for read access.
355 */
357 /*
358 * sdb_store_query_t:
359 * A parsed query readily prepared for execution.
360 */
361 struct sdb_store_query;
362 typedef struct sdb_store_query sdb_store_query_t;
364 /*
365 * sdb_store_query_prepare:
366 * Prepare the query described by 'ast' for execution in a store.
367 *
368 * Returns:
369 * - a store query on success
370 * - NULL else
371 */
372 sdb_store_query_t *
373 sdb_store_query_prepare(sdb_ast_node_t *ast);
375 /*
376 * sdb_store_query_prepare_matcher:
377 * Prepare the logical expression described by 'ast' for execution as a store
378 * matcher.
379 *
380 * Returns:
381 * - a matcher on success
382 * - NULL else
383 */
384 sdb_store_matcher_t *
385 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
387 /*
388 * sdb_store_query_execute:
389 * Execute a previously prepared query. The query result will be written to
390 * 'buf' and any errors to 'errbuf'.
391 *
392 * Returns:
393 * - the result type (to be used by the server reply)
394 * - a negative value on error
395 */
396 int
397 sdb_store_query_execute(sdb_store_query_t *m,
398 sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
400 /*
401 * sdb_store_expr_create:
402 * Creates an arithmetic expression implementing the specified operator on the
403 * specified left and right operand.
404 *
405 * Returns:
406 * - an expression object on success
407 * - NULL else
408 */
409 sdb_store_expr_t *
410 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
412 /*
413 * sdb_store_expr_typed:
414 * Creates an expression which evaluates in the context of an object's sibling
415 * as specified by the given type.
416 *
417 * Returns:
418 * - an expression object on success
419 * - NULL else
420 */
421 sdb_store_expr_t *
422 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
424 /*
425 * sdb_store_expr_fieldvalue:
426 * Creates an expression which evaluates to the value of the specified
427 * queryable field of a stored object.
428 *
429 * Returns:
430 * - an expression object on success
431 * - NULL else
432 */
433 sdb_store_expr_t *
434 sdb_store_expr_fieldvalue(int field);
436 /*
437 * sdb_store_expr_attrvalue:
438 * Creates an expression which evaluates to the value of the specified
439 * attribute of a stored object. Evaluates to a NULL value if the attribute
440 * does not exist.
441 *
442 * Returns:
443 * - an expression object on success
444 * - NULL else
445 */
446 sdb_store_expr_t *
447 sdb_store_expr_attrvalue(const char *name);
449 /*
450 * sdb_store_expr_constvalue:
451 * Creates an expression which evaluates to the specified constant value.
452 *
453 * Returns:
454 * - an expression object on success
455 * - NULL else
456 */
457 sdb_store_expr_t *
458 sdb_store_expr_constvalue(const sdb_data_t *value);
460 /*
461 * sdb_store_expr_eval:
462 * Evaluate an expression for the specified stored object and stores the
463 * result in 'res'. The result's value will be allocated dynamically if
464 * necessary and, thus, should be free'd by the caller (e.g. using
465 * sdb_data_free_datum). The object may be NULL, in which case the expression
466 * needs to evaluate to a constant value. If specified, only objects matching
467 * the filter will be used during the evaluation.
468 *
469 * Returns:
470 * - 0 on success
471 * - a negative value else
472 */
473 int
474 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
475 sdb_data_t *res, sdb_store_matcher_t *filter);
477 /*
478 * sdb_store_expr_iterable:
479 * Check whether an expression, evaluated in the specified context (HOST,
480 * SERVICE, METRIC) is iterable, that is, if it may evaluate to multiple
481 * values.
482 */
483 bool
484 sdb_store_expr_iterable(sdb_store_expr_t *expr, int context);
486 /*
487 * sdb_store_expr_iter:
488 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
489 * returns NULL if the expression is not iterable (for the specified object).
490 * See also sdb_store_expr_iterable.
491 *
492 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
493 */
494 sdb_store_expr_iter_t *
495 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
496 sdb_store_matcher_t *filter);
497 void
498 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
500 bool
501 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
502 sdb_data_t
503 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
505 /*
506 * sdb_store_dis_matcher:
507 * Creates a matcher matching the disjunction (logical OR) of two matchers.
508 */
509 sdb_store_matcher_t *
510 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
512 /*
513 * sdb_store_con_matcher:
514 * Creates a matcher matching the conjunction (logical AND) of two matchers.
515 */
516 sdb_store_matcher_t *
517 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
519 /*
520 * sdb_store_inv_matcher::
521 * Creates a matcher matching the inverse (logical NOT) of a matcher.
522 */
523 sdb_store_matcher_t *
524 sdb_store_inv_matcher(sdb_store_matcher_t *m);
526 /*
527 * sdb_store_any_matcher:
528 * Creates a matcher iterating over values of the first expression (which has
529 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
530 * to be an ary operation with the left operand unset.
531 */
532 sdb_store_matcher_t *
533 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
535 /*
536 * sdb_store_all_matcher:
537 * Creates a matcher iterating over values of the first expression (which has
538 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
539 * to be an ary operation with the left operand unset.
540 */
541 sdb_store_matcher_t *
542 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
544 /*
545 * sdb_store_in_matcher:
546 * Creates a matcher which matches if the right value evaluates to an array
547 * value and the left value is included in that array. See sdb_data_inarray
548 * for more details.
549 */
550 sdb_store_matcher_t *
551 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
553 /*
554 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
555 * sdb_store_ge_matcher, sdb_store_gt_matcher:
556 * Create conditional matchers comparing the values of two expressions. The
557 * matcher matches if the left expression compres less than, less or equal
558 * than, equal to, not equal to, greater or equal than, or greater than the
559 * right expression.
560 */
561 sdb_store_matcher_t *
562 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
563 sdb_store_matcher_t *
564 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
565 sdb_store_matcher_t *
566 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
567 sdb_store_matcher_t *
568 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
569 sdb_store_matcher_t *
570 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
571 sdb_store_matcher_t *
572 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
574 /*
575 * sdb_store_regex_matcher:
576 * Creates a matcher which matches the string value the left expression
577 * evaluates to against the regular expression the right expression evaluates
578 * to. The right expression may either be a constant value regular expression
579 * or string or a dynamic value evaluating to a string. In the latter case,
580 * the string is compiled to a regex every time the matcher is executed.
581 */
582 sdb_store_matcher_t *
583 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
585 /*
586 * sdb_store_nregex_matcher:
587 * Creates a regex matcher just like sdb_store_regex_matcher except that it
588 * matches in case the regular expression does not match.
589 */
590 sdb_store_matcher_t *
591 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
593 /*
594 * sdb_store_isnull_matcher:
595 * Creates a matcher matching NULL values.
596 */
597 sdb_store_matcher_t *
598 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
600 /*
601 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
602 * Creates a matcher matching boolean values.
603 */
604 sdb_store_matcher_t *
605 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
606 sdb_store_matcher_t *
607 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
609 /*
610 * sdb_store_matcher_matches:
611 * Check whether the specified matcher matches the specified store object. If
612 * specified, the filter will be used to preselect objects for further
613 * evaluation. It is applied to any object that's used during the evaluation
614 * of the matcher. Only those objects matching the filter will be considered.
615 *
616 * Note that the filter is applied to all object types (hosts, service,
617 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
618 * for this purpose and, if used, may result in unexpected behavior.
619 *
620 * Returns:
621 * - 1 if the object matches
622 * - 0 else
623 */
624 int
625 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
626 sdb_store_matcher_t *filter);
628 /*
629 * sdb_store_matcher_op_cb:
630 * Callback constructing a matcher operator.
631 */
632 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
633 (sdb_store_expr_t *, sdb_store_expr_t *);
635 /*
636 * sdb_store_lookup_cb:
637 * Lookup callback. It is called for each matching object when looking up data
638 * in the store passing on the lookup filter and the specified user-data. The
639 * lookup aborts early if the callback returns non-zero.
640 */
641 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
642 sdb_store_matcher_t *filter, void *user_data);
644 /*
645 * sdb_store_scan:
646 * Look up objects of the specified type in the store. The specified callback
647 * function is called for each object in the store matching 'm'. The function
648 * performs a full scan of all objects stored in the database. If specified,
649 * the filter will be used to preselect objects for further evaluation. See
650 * the description of 'sdb_store_matcher_matches' for details.
651 *
652 * Returns:
653 * - 0 on success
654 * - a negative value else
655 */
656 int
657 sdb_store_scan(int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
658 sdb_store_lookup_cb cb, void *user_data);
660 /*
661 * Flags for JSON formatting.
662 */
663 enum {
664 SDB_WANT_ARRAY = 1 << 0,
665 };
667 /*
668 * sdb_store_json_formatter:
669 * Create a JSON formatter for the specified object types writing to the
670 * specified buffer.
671 */
672 sdb_store_json_formatter_t *
673 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
675 /*
676 * sdb_store_json_emit:
677 * Serialize a single object to JSON adding it to the string buffer associated
678 * with the formatter object. The serialized object will not include
679 * attributes or any child objects. Instead, call the function again for each
680 * of those objects. All attributes have to be emitted before any other
681 * children types. Use sdb_store_json_emit_full() to emit a full (filtered)
682 * object.
683 *
684 * Note that the output might not be valid JSON before calling
685 * sdb_store_json_finish().
686 *
687 * Returns:
688 * - 0 on success
689 * - a negative value else
690 */
691 int
692 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj);
694 /*
695 * sdb_store_json_emit_full:
696 * Serialize a single object including it's attributes and all children to
697 * JSON, adding it to the string buffer associated with the formatter object.
698 * The filter, if specified, is applied to each attribute and child object.
699 * Only matching objects will be included in the output.
700 *
701 * Note that the output might not be valid JSON before calling
702 * sdb_store_json_finish().
703 *
704 * Returns:
705 * - 0 on success
706 * - a negative value else
707 */
708 int
709 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
710 sdb_store_matcher_t *filter);
712 /*
713 * sdb_store_json_finish:
714 * Finish the JSON output. This function has to be called once after emiting
715 * all objects.
716 */
717 int
718 sdb_store_json_finish(sdb_store_json_formatter_t *f);
720 #ifdef __cplusplus
721 } /* extern "C" */
722 #endif
724 #endif /* ! SDB_CORE_STORE_H */
726 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */