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 * sdb_store_init:
234 * Initialize the store sub-system. This function has to be called before
235 * doing any other store operations.
236 *
237 * Returns:
238 * - 0 on success
239 * - a negative value else
240 */
241 int
242 sdb_store_init(void);
244 /*
245 * sdb_store_clear:
246 * Clear the entire store and remove all stored objects.
247 */
248 void
249 sdb_store_clear(void);
251 /*
252 * sdb_store_get_host:
253 * Query the store for a host by its (canonicalized) name.
254 *
255 * The function increments the ref count of the host object. The caller needs
256 * to deref it when no longer using it.
257 */
258 sdb_store_obj_t *
259 sdb_store_get_host(const char *name);
261 /*
262 * sdb_store_fetch_timeseries:
263 * Fetch the time-series described by the specified host's metric and
264 * serialize it as JSON into the provided string buffer.
265 *
266 * Returns:
267 * - 0 on success
268 * - a negative value else
269 */
270 int
271 sdb_store_fetch_timeseries(const char *hostname, const char *metric,
272 sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
274 /*
275 * sdb_store_get_child:
276 * Retrieve a host's child object of the specified type and name. The
277 * reference count of the child object will be incremented before returning
278 * it. The caller is responsible for releasing the object once it's no longer
279 * used.
280 *
281 * Returns:
282 * - the child object on success
283 * - NULL else
284 */
285 sdb_store_obj_t *
286 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
288 /*
289 * sdb_store_get_field:
290 * Get the value of a stored object's queryable field. The caller is
291 * responsible for freeing any dynamically allocated memory possibly stored in
292 * the returned value. If 'res' is NULL, the function will return whether the
293 * field exists.
294 *
295 * Returns:
296 * - 0 on success
297 * - a negative value else
298 */
299 int
300 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
302 /*
303 * sdb_store_get_attr:
304 * Get the value of a stored object's attribute. The caller is responsible for
305 * freeing any dynamically allocated memory possibly stored in the returned
306 * value. If 'res' is NULL, the function will return whether the attribute
307 * exists. If specified, only attributes matching the filter will be
308 * considered.
309 *
310 * Returns:
311 * - 0 if the attribute exists
312 * - a negative value else
313 */
314 int
315 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
316 sdb_store_matcher_t *filter);
318 /*
319 * Querying a store:
320 *
321 * - Query interface: A query is a formal description of an interaction with
322 * the store. It can be used, both, for read and write access. The query is
323 * described by its abstract syntax tree (AST). The parser package provides
324 * means to parse a string (SysQL) representation of the query into an AST.
325 *
326 * - Matcher / expression interface: This low-level interface provides direct
327 * control over how to access the store. It is used by the query
328 * implementation internally and can only be used for read access.
329 */
331 /*
332 * sdb_store_query_t:
333 * A parsed query readily prepared for execution.
334 */
335 struct sdb_store_query;
336 typedef struct sdb_store_query sdb_store_query_t;
338 /*
339 * sdb_store_query_prepare:
340 * Prepare the query described by 'ast' for execution in a store.
341 *
342 * Returns:
343 * - a store query on success
344 * - NULL else
345 */
346 sdb_store_query_t *
347 sdb_store_query_prepare(sdb_ast_node_t *ast);
349 /*
350 * sdb_store_query_prepare_matcher:
351 * Prepare the logical expression described by 'ast' for execution as a store
352 * matcher.
353 *
354 * Returns:
355 * - a matcher on success
356 * - NULL else
357 */
358 sdb_store_matcher_t *
359 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
361 /*
362 * sdb_store_query_execute:
363 * Execute a previously prepared query. The query result will be written to
364 * 'buf' and any errors to 'errbuf'.
365 *
366 * Returns:
367 * - the result type (to be used by the server reply)
368 * - a negative value on error
369 */
370 int
371 sdb_store_query_execute(sdb_store_query_t *m,
372 sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
374 /*
375 * sdb_store_expr_create:
376 * Creates an arithmetic expression implementing the specified operator on the
377 * specified left and right operand.
378 *
379 * Returns:
380 * - an expression object on success
381 * - NULL else
382 */
383 sdb_store_expr_t *
384 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
386 /*
387 * sdb_store_expr_typed:
388 * Creates an expression which evaluates in the context of an object's sibling
389 * as specified by the given type.
390 *
391 * Returns:
392 * - an expression object on success
393 * - NULL else
394 */
395 sdb_store_expr_t *
396 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
398 /*
399 * sdb_store_expr_fieldvalue:
400 * Creates an expression which evaluates to the value of the specified
401 * queryable field of a stored object.
402 *
403 * Returns:
404 * - an expression object on success
405 * - NULL else
406 */
407 sdb_store_expr_t *
408 sdb_store_expr_fieldvalue(int field);
410 /*
411 * sdb_store_expr_attrvalue:
412 * Creates an expression which evaluates to the value of the specified
413 * attribute of a stored object. Evaluates to a NULL value if the attribute
414 * does not exist.
415 *
416 * Returns:
417 * - an expression object on success
418 * - NULL else
419 */
420 sdb_store_expr_t *
421 sdb_store_expr_attrvalue(const char *name);
423 /*
424 * sdb_store_expr_constvalue:
425 * Creates an expression which evaluates to the specified constant value.
426 *
427 * Returns:
428 * - an expression object on success
429 * - NULL else
430 */
431 sdb_store_expr_t *
432 sdb_store_expr_constvalue(const sdb_data_t *value);
434 /*
435 * sdb_store_expr_eval:
436 * Evaluate an expression for the specified stored object and stores the
437 * result in 'res'. The result's value will be allocated dynamically if
438 * necessary and, thus, should be free'd by the caller (e.g. using
439 * sdb_data_free_datum). The object may be NULL, in which case the expression
440 * needs to evaluate to a constant value. If specified, only objects matching
441 * the filter will be used during the evaluation.
442 *
443 * Returns:
444 * - 0 on success
445 * - a negative value else
446 */
447 int
448 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
449 sdb_data_t *res, sdb_store_matcher_t *filter);
451 /*
452 * sdb_store_expr_iterable:
453 * Check whether an expression, evaluated in the specified context (HOST,
454 * SERVICE, METRIC) is iterable, that is, if it may evaluate to multiple
455 * values.
456 */
457 bool
458 sdb_store_expr_iterable(sdb_store_expr_t *expr, int context);
460 /*
461 * sdb_store_expr_iter:
462 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
463 * returns NULL if the expression is not iterable (for the specified object).
464 * See also sdb_store_expr_iterable.
465 *
466 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
467 */
468 sdb_store_expr_iter_t *
469 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
470 sdb_store_matcher_t *filter);
471 void
472 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
474 bool
475 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
476 sdb_data_t
477 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
479 /*
480 * sdb_store_dis_matcher:
481 * Creates a matcher matching the disjunction (logical OR) of two matchers.
482 */
483 sdb_store_matcher_t *
484 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
486 /*
487 * sdb_store_con_matcher:
488 * Creates a matcher matching the conjunction (logical AND) of two matchers.
489 */
490 sdb_store_matcher_t *
491 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
493 /*
494 * sdb_store_inv_matcher::
495 * Creates a matcher matching the inverse (logical NOT) of a matcher.
496 */
497 sdb_store_matcher_t *
498 sdb_store_inv_matcher(sdb_store_matcher_t *m);
500 /*
501 * sdb_store_any_matcher:
502 * Creates a matcher iterating over values of the first expression (which has
503 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
504 * to be an ary operation with the left operand unset.
505 */
506 sdb_store_matcher_t *
507 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
509 /*
510 * sdb_store_all_matcher:
511 * Creates a matcher iterating over values of the first expression (which has
512 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
513 * to be an ary operation with the left operand unset.
514 */
515 sdb_store_matcher_t *
516 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
518 /*
519 * sdb_store_in_matcher:
520 * Creates a matcher which matches if the right value evaluates to an array
521 * value and the left value is included in that array. See sdb_data_inarray
522 * for more details.
523 */
524 sdb_store_matcher_t *
525 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
527 /*
528 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
529 * sdb_store_ge_matcher, sdb_store_gt_matcher:
530 * Create conditional matchers comparing the values of two expressions. The
531 * matcher matches if the left expression compres less than, less or equal
532 * than, equal to, not equal to, greater or equal than, or greater than the
533 * right expression.
534 */
535 sdb_store_matcher_t *
536 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
537 sdb_store_matcher_t *
538 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
539 sdb_store_matcher_t *
540 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
541 sdb_store_matcher_t *
542 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
543 sdb_store_matcher_t *
544 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
545 sdb_store_matcher_t *
546 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
548 /*
549 * sdb_store_regex_matcher:
550 * Creates a matcher which matches the string value the left expression
551 * evaluates to against the regular expression the right expression evaluates
552 * to. The right expression may either be a constant value regular expression
553 * or string or a dynamic value evaluating to a string. In the latter case,
554 * the string is compiled to a regex every time the matcher is executed.
555 */
556 sdb_store_matcher_t *
557 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
559 /*
560 * sdb_store_nregex_matcher:
561 * Creates a regex matcher just like sdb_store_regex_matcher except that it
562 * matches in case the regular expression does not match.
563 */
564 sdb_store_matcher_t *
565 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
567 /*
568 * sdb_store_isnull_matcher:
569 * Creates a matcher matching NULL values.
570 */
571 sdb_store_matcher_t *
572 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
574 /*
575 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
576 * Creates a matcher matching boolean values.
577 */
578 sdb_store_matcher_t *
579 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
580 sdb_store_matcher_t *
581 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
583 /*
584 * sdb_store_matcher_matches:
585 * Check whether the specified matcher matches the specified store object. If
586 * specified, the filter will be used to preselect objects for further
587 * evaluation. It is applied to any object that's used during the evaluation
588 * of the matcher. Only those objects matching the filter will be considered.
589 *
590 * Note that the filter is applied to all object types (hosts, service,
591 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
592 * for this purpose and, if used, may result in unexpected behavior.
593 *
594 * Returns:
595 * - 1 if the object matches
596 * - 0 else
597 */
598 int
599 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
600 sdb_store_matcher_t *filter);
602 /*
603 * sdb_store_matcher_op_cb:
604 * Callback constructing a matcher operator.
605 */
606 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
607 (sdb_store_expr_t *, sdb_store_expr_t *);
609 /*
610 * sdb_store_lookup_cb:
611 * Lookup callback. It is called for each matching object when looking up data
612 * in the store passing on the lookup filter and the specified user-data. The
613 * lookup aborts early if the callback returns non-zero.
614 */
615 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
616 sdb_store_matcher_t *filter, void *user_data);
618 /*
619 * sdb_store_scan:
620 * Look up objects of the specified type in the store. The specified callback
621 * function is called for each object in the store matching 'm'. The function
622 * performs a full scan of all objects stored in the database. If specified,
623 * the filter will be used to preselect objects for further evaluation. See
624 * the description of 'sdb_store_matcher_matches' for details.
625 *
626 * Returns:
627 * - 0 on success
628 * - a negative value else
629 */
630 int
631 sdb_store_scan(int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
632 sdb_store_lookup_cb cb, void *user_data);
634 /*
635 * Flags for JSON formatting.
636 */
637 enum {
638 SDB_WANT_ARRAY = 1 << 0,
639 };
641 /*
642 * sdb_store_json_formatter:
643 * Create a JSON formatter for the specified object types writing to the
644 * specified buffer.
645 */
646 sdb_store_json_formatter_t *
647 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
649 /*
650 * sdb_store_json_emit:
651 * Serialize a single object to JSON adding it to the string buffer associated
652 * with the formatter object. The serialized object will not include
653 * attributes or any child objects. Instead, call the function again for each
654 * of those objects. All attributes have to be emitted before any other
655 * children types. Use sdb_store_json_emit_full() to emit a full (filtered)
656 * object.
657 *
658 * Note that the output might not be valid JSON before calling
659 * sdb_store_json_finish().
660 *
661 * Returns:
662 * - 0 on success
663 * - a negative value else
664 */
665 int
666 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj);
668 /*
669 * sdb_store_json_emit_full:
670 * Serialize a single object including it's attributes and all children to
671 * JSON, adding it to the string buffer associated with the formatter object.
672 * The filter, if specified, is applied to each attribute and child object.
673 * Only matching objects will be included in the output.
674 *
675 * Note that the output might not be valid JSON before calling
676 * sdb_store_json_finish().
677 *
678 * Returns:
679 * - 0 on success
680 * - a negative value else
681 */
682 int
683 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
684 sdb_store_matcher_t *filter);
686 /*
687 * sdb_store_json_finish:
688 * Finish the JSON output. This function has to be called once after emiting
689 * all objects.
690 */
691 int
692 sdb_store_json_finish(sdb_store_json_formatter_t *f);
694 #ifdef __cplusplus
695 } /* extern "C" */
696 #endif
698 #endif /* ! SDB_CORE_STORE_H */
700 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */