15f435fefdc6136a83fdb2e53a004a5cac82e8a9
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 struct sdb_store_json_formatter;
149 typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
151 /*
152 * A store writer describes the interface for plugins implementing a store.
153 *
154 * Any of the call-back functions shall return:
155 * - 0 on success
156 * - a positive value if the new entry is older than the currently stored
157 * entry (in this case, no update will happen)
158 * - a negative value on error
159 */
160 typedef struct {
161 /*
162 * store_host:
163 * Add/update a host in the store. If the host, identified by its
164 * canonicalized name, already exists, it will be updated according to the
165 * specified name and timestamp. Else, a new entry will be created in the
166 * store.
167 */
168 int (*store_host)(const char *name, sdb_time_t last_update,
169 sdb_object_t *user_data);
171 /*
172 * store_service:
173 * Add/update a service in the store. If the service, identified by its
174 * name, already exists for the specified host, it will be updated
175 * according to the specified name and timestamp. If the referenced host
176 * does not exist, an error will be reported. Else, a new entry will be
177 * created in the store.
178 */
179 int (*store_service)(const char *hostname, const char *name,
180 sdb_time_t last_update, sdb_object_t *user_data);
182 /*
183 * store_metric:
184 * Add/update a metric in the store. If the metric, identified by its
185 * name, already exists for the specified host, it will be updated
186 * according to the specified attributes. If the referenced host does not
187 * exist, an error will be reported. Else, a new entry will be created in
188 * the store.
189 */
190 int (*store_metric)(const char *hostname, const char *name,
191 sdb_metric_store_t *store, sdb_time_t last_update,
192 sdb_object_t *user_data);
194 /*
195 * store_attribute:
196 * Add/update a host's attribute in the store. If the attribute,
197 * identified by its key, already exists for the specified host, it will
198 * be updated to the specified values. If the referenced host does not
199 * exist, an error will be reported. Else, a new entry will be created in
200 * the store.
201 */
202 int (*store_attribute)(const char *hostname,
203 const char *key, const sdb_data_t *value, sdb_time_t last_update,
204 sdb_object_t *user_data);
206 /*
207 * store_service_attr:
208 * Add/update a service's attribute in the store. If the attribute,
209 * identified by its key, already exists for the specified service, it
210 * will be updated to the specified value. If the references service (for
211 * the specified host) does not exist, an error will be reported.
212 */
213 int (*store_service_attr)(const char *hostname, const char *service,
214 const char *key, const sdb_data_t *value, sdb_time_t last_update,
215 sdb_object_t *user_data);
217 /*
218 * store_metric_attr:
219 * Add/update a metric's attribute in the store. If the attribute,
220 * identified by its key, already exists for the specified metric, it will
221 * be updated to the specified value. If the references metric (for the
222 * specified host) does not exist, an error will be reported.
223 */
224 int (*store_metric_attr)(const char *hostname, const char *metric,
225 const char *key, const sdb_data_t *value, sdb_time_t last_update,
226 sdb_object_t *user_data);
227 } sdb_store_writer_t;
229 /*
230 * sdb_store_init:
231 * Initialize the store sub-system. This function has to be called before
232 * doing any other store operations.
233 *
234 * Returns:
235 * - 0 on success
236 * - a negative value else
237 */
238 int
239 sdb_store_init(void);
241 /*
242 * sdb_store_clear:
243 * Clear the entire store and remove all stored objects.
244 */
245 void
246 sdb_store_clear(void);
248 /*
249 * sdb_store_has_host:
250 * sdb_store_get_host:
251 * Query the store for a host by its (canonicalized) name.
252 *
253 * sdb_store_get_host increments the ref count of the host object. The caller
254 * needs to deref it when no longer using it.
255 */
256 bool
257 sdb_store_has_host(const char *name);
259 sdb_store_obj_t *
260 sdb_store_get_host(const char *name);
262 /*
263 * sdb_store_fetch_timeseries:
264 * Fetch the time-series described by the specified host's metric and
265 * serialize it as JSON into the provided string buffer.
266 *
267 * Returns:
268 * - 0 on success
269 * - a negative value else
270 */
271 int
272 sdb_store_fetch_timeseries(const char *hostname, const char *metric,
273 sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
275 /*
276 * sdb_store_get_child:
277 * Retrieve a host's child object of the specified type and name. The
278 * reference count of the child object will be incremented before returning
279 * it. The caller is responsible for releasing the object once it's no longer
280 * used.
281 *
282 * Returns:
283 * - the child object on success
284 * - NULL else
285 */
286 sdb_store_obj_t *
287 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
289 /*
290 * sdb_store_get_field:
291 * Get the value of a stored object's queryable field. The caller is
292 * responsible for freeing any dynamically allocated memory possibly stored in
293 * the returned value. If 'res' is NULL, the function will return whether the
294 * field exists.
295 *
296 * Returns:
297 * - 0 on success
298 * - a negative value else
299 */
300 int
301 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
303 /*
304 * sdb_store_get_attr:
305 * Get the value of a stored object's attribute. The caller is responsible for
306 * freeing any dynamically allocated memory possibly stored in the returned
307 * value. If 'res' is NULL, the function will return whether the attribute
308 * exists. If specified, only attributes matching the filter will be
309 * considered.
310 *
311 * Returns:
312 * - 0 if the attribute exists
313 * - a negative value else
314 */
315 int
316 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
317 sdb_store_matcher_t *filter);
319 /*
320 * Querying a store:
321 *
322 * - Query interface: A query is a formal description of an interaction with
323 * the store. It can be used, both, for read and write access. The query is
324 * described by its abstract syntax tree (AST). The parser package provides
325 * means to parse a string (SysQL) representation of the query into an AST.
326 *
327 * - Matcher / expression interface: This low-level interface provides direct
328 * control over how to access the store. It is used by the query
329 * implementation internally and can only be used for read access.
330 */
332 /*
333 * sdb_store_query_t:
334 * A parsed query readily prepared for execution.
335 */
336 struct sdb_store_query;
337 typedef struct sdb_store_query sdb_store_query_t;
339 /*
340 * sdb_store_query_prepare:
341 * Prepare the query described by 'ast' for execution in a store.
342 *
343 * Returns:
344 * - a store query on success
345 * - NULL else
346 */
347 sdb_store_query_t *
348 sdb_store_query_prepare(sdb_ast_node_t *ast);
350 /*
351 * sdb_store_query_prepare_matcher:
352 * Prepare the logical expression described by 'ast' for execution as a store
353 * matcher.
354 *
355 * Returns:
356 * - a matcher on success
357 * - NULL else
358 */
359 sdb_store_matcher_t *
360 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
362 /*
363 * sdb_store_query_execute:
364 * Execute a previously prepared query. The query result will be written to
365 * 'buf' and any errors to 'errbuf'.
366 *
367 * Returns:
368 * - the result type (to be used by the server reply)
369 * - a negative value on error
370 */
371 int
372 sdb_store_query_execute(sdb_store_query_t *m,
373 sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
375 /*
376 * sdb_store_expr_create:
377 * Creates an arithmetic expression implementing the specified operator on the
378 * specified left and right operand.
379 *
380 * Returns:
381 * - an expression object on success
382 * - NULL else
383 */
384 sdb_store_expr_t *
385 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
387 /*
388 * sdb_store_expr_typed:
389 * Creates an expression which evaluates in the context of an object's sibling
390 * as specified by the given type.
391 *
392 * Returns:
393 * - an expression object on success
394 * - NULL else
395 */
396 sdb_store_expr_t *
397 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
399 /*
400 * sdb_store_expr_fieldvalue:
401 * Creates an expression which evaluates to the value of the specified
402 * queryable field of a stored object.
403 *
404 * Returns:
405 * - an expression object on success
406 * - NULL else
407 */
408 sdb_store_expr_t *
409 sdb_store_expr_fieldvalue(int field);
411 /*
412 * sdb_store_expr_attrvalue:
413 * Creates an expression which evaluates to the value of the specified
414 * attribute of a stored object. Evaluates to a NULL value if the attribute
415 * does not exist.
416 *
417 * Returns:
418 * - an expression object on success
419 * - NULL else
420 */
421 sdb_store_expr_t *
422 sdb_store_expr_attrvalue(const char *name);
424 /*
425 * sdb_store_expr_constvalue:
426 * Creates an expression which evaluates to the specified constant value.
427 *
428 * Returns:
429 * - an expression object on success
430 * - NULL else
431 */
432 sdb_store_expr_t *
433 sdb_store_expr_constvalue(const sdb_data_t *value);
435 /*
436 * sdb_store_expr_eval:
437 * Evaluate an expression for the specified stored object and stores the
438 * result in 'res'. The result's value will be allocated dynamically if
439 * necessary and, thus, should be free'd by the caller (e.g. using
440 * sdb_data_free_datum). The object may be NULL, in which case the expression
441 * needs to evaluate to a constant value. If specified, only objects matching
442 * the filter will be used during the evaluation.
443 *
444 * Returns:
445 * - 0 on success
446 * - a negative value else
447 */
448 int
449 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
450 sdb_data_t *res, sdb_store_matcher_t *filter);
452 /*
453 * sdb_store_expr_iterable:
454 * Check whether an expression, evaluated in the specified context (HOST,
455 * SERVICE, METRIC) is iterable, that is, if it may evaluate to multiple
456 * values.
457 */
458 bool
459 sdb_store_expr_iterable(sdb_store_expr_t *expr, int context);
461 /*
462 * sdb_store_expr_iter:
463 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
464 * returns NULL if the expression is not iterable (for the specified object).
465 * See also sdb_store_expr_iterable.
466 *
467 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
468 */
469 sdb_store_expr_iter_t *
470 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
471 sdb_store_matcher_t *filter);
472 void
473 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
475 bool
476 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
477 sdb_data_t
478 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
480 /*
481 * sdb_store_dis_matcher:
482 * Creates a matcher matching the disjunction (logical OR) of two matchers.
483 */
484 sdb_store_matcher_t *
485 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
487 /*
488 * sdb_store_con_matcher:
489 * Creates a matcher matching the conjunction (logical AND) of two matchers.
490 */
491 sdb_store_matcher_t *
492 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
494 /*
495 * sdb_store_inv_matcher::
496 * Creates a matcher matching the inverse (logical NOT) of a matcher.
497 */
498 sdb_store_matcher_t *
499 sdb_store_inv_matcher(sdb_store_matcher_t *m);
501 /*
502 * sdb_store_any_matcher:
503 * Creates a matcher iterating over values of the first expression (which has
504 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
505 * to be an ary operation with the left operand unset.
506 */
507 sdb_store_matcher_t *
508 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
510 /*
511 * sdb_store_all_matcher:
512 * Creates a matcher iterating over values of the first expression (which has
513 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
514 * to be an ary operation with the left operand unset.
515 */
516 sdb_store_matcher_t *
517 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
519 /*
520 * sdb_store_in_matcher:
521 * Creates a matcher which matches if the right value evaluates to an array
522 * value and the left value is included in that array. See sdb_data_inarray
523 * for more details.
524 */
525 sdb_store_matcher_t *
526 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
528 /*
529 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
530 * sdb_store_ge_matcher, sdb_store_gt_matcher:
531 * Create conditional matchers comparing the values of two expressions. The
532 * matcher matches if the left expression compres less than, less or equal
533 * than, equal to, not equal to, greater or equal than, or greater than the
534 * right expression.
535 */
536 sdb_store_matcher_t *
537 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
538 sdb_store_matcher_t *
539 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
540 sdb_store_matcher_t *
541 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
542 sdb_store_matcher_t *
543 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
544 sdb_store_matcher_t *
545 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
546 sdb_store_matcher_t *
547 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
549 /*
550 * sdb_store_regex_matcher:
551 * Creates a matcher which matches the string value the left expression
552 * evaluates to against the regular expression the right expression evaluates
553 * to. The right expression may either be a constant value regular expression
554 * or string or a dynamic value evaluating to a string. In the latter case,
555 * the string is compiled to a regex every time the matcher is executed.
556 */
557 sdb_store_matcher_t *
558 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
560 /*
561 * sdb_store_nregex_matcher:
562 * Creates a regex matcher just like sdb_store_regex_matcher except that it
563 * matches in case the regular expression does not match.
564 */
565 sdb_store_matcher_t *
566 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
568 /*
569 * sdb_store_isnull_matcher:
570 * Creates a matcher matching NULL values.
571 */
572 sdb_store_matcher_t *
573 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
575 /*
576 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
577 * Creates a matcher matching boolean values.
578 */
579 sdb_store_matcher_t *
580 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
581 sdb_store_matcher_t *
582 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
584 /*
585 * sdb_store_matcher_matches:
586 * Check whether the specified matcher matches the specified store object. If
587 * specified, the filter will be used to preselect objects for further
588 * evaluation. It is applied to any object that's used during the evaluation
589 * of the matcher. Only those objects matching the filter will be considered.
590 *
591 * Note that the filter is applied to all object types (hosts, service,
592 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
593 * for this purpose and, if used, may result in unexpected behavior.
594 *
595 * Returns:
596 * - 1 if the object matches
597 * - 0 else
598 */
599 int
600 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
601 sdb_store_matcher_t *filter);
603 /*
604 * sdb_store_matcher_op_cb:
605 * Callback constructing a matcher operator.
606 */
607 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
608 (sdb_store_expr_t *, sdb_store_expr_t *);
610 /*
611 * sdb_store_lookup_cb:
612 * Lookup callback. It is called for each matching object when looking up data
613 * in the store passing on the lookup filter and the specified user-data. The
614 * lookup aborts early if the callback returns non-zero.
615 */
616 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
617 sdb_store_matcher_t *filter, void *user_data);
619 /*
620 * sdb_store_scan:
621 * Look up objects of the specified type in the store. The specified callback
622 * function is called for each object in the store matching 'm'. The function
623 * performs a full scan of all objects stored in the database. If specified,
624 * the filter will be used to preselect objects for further evaluation. See
625 * the description of 'sdb_store_matcher_matches' for details.
626 *
627 * Returns:
628 * - 0 on success
629 * - a negative value else
630 */
631 int
632 sdb_store_scan(int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
633 sdb_store_lookup_cb cb, void *user_data);
635 /*
636 * Flags for JSON formatting.
637 */
638 enum {
639 SDB_WANT_ARRAY = 1 << 0,
640 };
642 /*
643 * sdb_store_json_formatter:
644 * Create a JSON formatter for the specified object types writing to the
645 * specified buffer.
646 */
647 sdb_store_json_formatter_t *
648 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
650 /*
651 * sdb_store_json_emit:
652 * Serialize a single object to JSON adding it to the string buffer associated
653 * with the formatter object. The serialized object will not include
654 * attributes or any child objects. Instead, call the function again for each
655 * of those objects. All attributes have to be emitted before any other
656 * children types. Use sdb_store_json_emit_full() to emit a full (filtered)
657 * object.
658 *
659 * Note that the output might not be valid JSON before calling
660 * sdb_store_json_finish().
661 *
662 * Returns:
663 * - 0 on success
664 * - a negative value else
665 */
666 int
667 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj);
669 /*
670 * sdb_store_json_emit_full:
671 * Serialize a single object including it's attributes and all children to
672 * JSON, adding it to the string buffer associated with the formatter object.
673 * The filter, if specified, is applied to each attribute and child object.
674 * Only matching objects will be included in the output.
675 *
676 * Note that the output might not be valid JSON before calling
677 * sdb_store_json_finish().
678 *
679 * Returns:
680 * - 0 on success
681 * - a negative value else
682 */
683 int
684 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
685 sdb_store_matcher_t *filter);
687 /*
688 * sdb_store_json_finish:
689 * Finish the JSON output. This function has to be called once after emiting
690 * all objects.
691 */
692 int
693 sdb_store_json_finish(sdb_store_json_formatter_t *f);
695 #ifdef __cplusplus
696 } /* extern "C" */
697 #endif
699 #endif /* ! SDB_CORE_STORE_H */
701 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */