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 };
66 #define SDB_STORE_TYPE_TO_NAME(t) \
67 (((t) == SDB_HOST) ? "host" \
68 : ((t) == SDB_SERVICE) ? "service" \
69 : ((t) == SDB_METRIC) ? "metric" \
70 : ((t) == SDB_ATTRIBUTE) ? "attribute" \
71 : ((t) == (SDB_ATTRIBUTE | SDB_HOST)) ? "host attribute" \
72 : ((t) == (SDB_ATTRIBUTE | SDB_SERVICE)) ? "service attribute" \
73 : ((t) == (SDB_ATTRIBUTE | SDB_METRIC)) ? "metric attribute" \
74 : "unknown")
76 #define SDB_FIELD_TO_NAME(f) \
77 (((f) == SDB_FIELD_NAME) ? "name" \
78 : ((f) == SDB_FIELD_LAST_UPDATE) ? "last-update" \
79 : ((f) == SDB_FIELD_AGE) ? "age" \
80 : ((f) == SDB_FIELD_INTERVAL) ? "interval" \
81 : ((f) == SDB_FIELD_BACKEND) ? "backend" \
82 : ((f) == SDB_FIELD_VALUE) ? "value" \
83 : "unknown")
85 #define SDB_FIELD_TYPE(f) \
86 (((f) == SDB_FIELD_NAME) ? SDB_TYPE_STRING \
87 : ((f) == SDB_FIELD_LAST_UPDATE) ? SDB_TYPE_DATETIME \
88 : ((f) == SDB_FIELD_AGE) ? SDB_TYPE_DATETIME \
89 : ((f) == SDB_FIELD_INTERVAL) ? SDB_TYPE_DATETIME \
90 : ((f) == SDB_FIELD_BACKEND) ? (SDB_TYPE_ARRAY | SDB_TYPE_STRING) \
91 : ((f) == SDB_FIELD_VALUE) ? -1 /* unknown */ \
92 : -1)
94 /*
95 * sdb_store_obj_t represents the super-class of any object stored in the
96 * database. It inherits from sdb_object_t and may safely be cast to a generic
97 * object to access its name.
98 */
99 struct sdb_store_obj;
100 typedef struct sdb_store_obj sdb_store_obj_t;
102 /*
103 * A metric store describes how to access a metric's data.
104 */
105 typedef struct {
106 const char *type;
107 const char *id;
108 } sdb_metric_store_t;
110 /*
111 * Expressions represent arithmetic expressions based on stored objects and
112 * their various attributes.
113 *
114 * An expression object inherits from sdb_object_t and, thus, may safely be
115 * cast to a generic object.
116 */
117 struct sdb_store_expr;
118 typedef struct sdb_store_expr sdb_store_expr_t;
119 #define SDB_STORE_EXPR(obj) ((sdb_store_expr_t *)(obj))
121 /*
122 * An expression iterator iterates over the values of an iterable expression
123 * (see sdb_store_expr_iterable).
124 */
125 struct sdb_store_expr_iter;
126 typedef struct sdb_store_expr_iter sdb_store_expr_iter_t;
128 /*
129 * Store matchers may be used to lookup hosts from the store based on their
130 * various attributes. Service and attribute matchers are applied to a host's
131 * services and attributes and evaluate to true if *any* service or attribute
132 * matches.
133 *
134 * A store matcher object inherits from sdb_object_t and, thus, may safely be
135 * cast to a generic object.
136 */
137 struct sdb_store_matcher;
138 typedef struct sdb_store_matcher sdb_store_matcher_t;
139 #define SDB_STORE_MATCHER(obj) ((sdb_store_matcher_t *)(obj))
141 /*
142 * A JSON formatter converts stored objects into the JSON format.
143 * See http://www.ietf.org/rfc/rfc4627.txt
144 */
145 struct sdb_store_json_formatter;
146 typedef struct sdb_store_json_formatter sdb_store_json_formatter_t;
148 /*
149 * A store writer describes the interface for plugins implementing a store.
150 */
151 typedef struct {
152 int (*store_host)(const char *name, sdb_time_t last_update,
153 sdb_object_t *user_data);
154 int (*store_service)(const char *hostname, const char *name,
155 sdb_time_t last_update, sdb_object_t *user_data);
156 int (*store_metric)(const char *hostname, const char *name,
157 sdb_metric_store_t *store, sdb_time_t last_update,
158 sdb_object_t *user_data);
159 int (*store_attribute)(const char *hostname,
160 const char *key, const sdb_data_t *value, sdb_time_t last_update,
161 sdb_object_t *user_data);
162 int (*store_service_attr)(const char *hostname, const char *service,
163 const char *key, const sdb_data_t *value, sdb_time_t last_update,
164 sdb_object_t *user_data);
165 int (*store_metric_attr)(const char *hostname, const char *metric,
166 const char *key, const sdb_data_t *value, sdb_time_t last_update,
167 sdb_object_t *user_data);
168 } sdb_store_writer_t;
170 /*
171 * sdb_store_clear:
172 * Clear the entire store and remove all stored objects.
173 */
174 void
175 sdb_store_clear(void);
177 /*
178 * sdb_store_host:
179 * Add/update a host in the store. If the host, identified by its
180 * canonicalized name, already exists, it will be updated according to the
181 * specified name and timestamp. Else, a new entry will be created in the
182 * store. Any memory required for storing the entry will be allocated an
183 * managed by the store itself.
184 *
185 * Returns:
186 * - 0 on success
187 * - a positive value if the new entry is older than the currently stored
188 * entry (in this case, no update will happen)
189 * - a negative value on error
190 */
191 int
192 sdb_store_host(const char *name, sdb_time_t last_update);
194 /*
195 * sdb_store_has_host:
196 * sdb_store_get_host:
197 * Query the store for a host by its (canonicalized) name.
198 *
199 * sdb_store_get_host increments the ref count of the host object. The caller
200 * needs to deref it when no longer using it.
201 */
202 bool
203 sdb_store_has_host(const char *name);
205 sdb_store_obj_t *
206 sdb_store_get_host(const char *name);
208 /*
209 * sdb_store_attribute:
210 * Add/update a host's attribute in the store. If the attribute, identified by
211 * its key, already exists for the specified host, it will be updated to the
212 * specified values. If the referenced host does not exist, an error will be
213 * reported. Else, a new entry will be created in the store. Any memory
214 * required for storing the entry will be allocated and managed by the store
215 * itself.
216 *
217 * Returns:
218 * - 0 on success
219 * - a positive value if the new entry is older than the currently stored
220 * entry (in this case, no update will happen)
221 * - a negative value on error
222 */
223 int
224 sdb_store_attribute(const char *hostname,
225 const char *key, const sdb_data_t *value,
226 sdb_time_t last_update);
228 /*
229 * sdb_store_service:
230 * Add/update a service in the store. If the service, identified by its name,
231 * already exists for the specified host, it will be updated according to the
232 * specified 'service' object. If the referenced host does not exist, an error
233 * will be reported. Else, a new entry will be created in the store. Any
234 * memory required for storing the entry will be allocated an managed by the
235 * store itself.
236 *
237 * Returns:
238 * - 0 on success
239 * - a positive value if the new entry is older than the currently stored
240 * entry (in this case, no update will happen)
241 * - a negative value on error
242 */
243 int
244 sdb_store_service(const char *hostname, const char *name,
245 sdb_time_t last_update);
247 /*
248 * sdb_store_service_attr:
249 * Add/update a service's attribute in the store. If the attribute, identified
250 * by its key, already exists for the specified service, it will be updated to
251 * the specified value. If the references service (for the specified host)
252 * does not exist, an error will be reported. Any memory required for storing
253 * the entry will be allocated and managed by the store itself.
254 *
255 * Returns:
256 * - 0 on success
257 * - a positive value if the new entry is older than the currently stored
258 * entry (in this case, no update will happen)
259 * - a negative value on error
260 */
261 int
262 sdb_store_service_attr(const char *hostname, const char *service,
263 const char *key, const sdb_data_t *value, sdb_time_t last_update);
265 /*
266 * sdb_store_metric:
267 * Add/update a metric in the store. If the metric, identified by its name,
268 * already exists for the specified host, it will be updated according to the
269 * specified 'metric' object. If the referenced host does not exist, an error
270 * will be reported. Else, a new entry will be created in the store. Any
271 * memory required for storing the entry will be allocated an managed by the
272 * store itself.
273 *
274 * If specified, the metric store describes where to access the metric's data.
275 *
276 * Returns:
277 * - 0 on success
278 * - a positive value if the new entry is older than the currently stored
279 * entry (in this case, no update will happen)
280 * - a negative value on error
281 */
282 int
283 sdb_store_metric(const char *hostname, const char *name,
284 sdb_metric_store_t *store, sdb_time_t last_update);
286 /*
287 * sdb_store_metric_attr:
288 * Add/update a metric's attribute in the store. If the attribute, identified
289 * by its key, already exists for the specified metric, it will be updated to
290 * the specified value. If the references metric (for the specified host)
291 * does not exist, an error will be reported. Any memory required for storing
292 * the entry will be allocated and managed by the store itself.
293 *
294 * Returns:
295 * - 0 on success
296 * - a positive value if the new entry is older than the currently stored
297 * entry (in this case, no update will happen)
298 * - a negative value on error
299 */
300 int
301 sdb_store_metric_attr(const char *hostname, const char *metric,
302 const char *key, const sdb_data_t *value, sdb_time_t last_update);
304 /*
305 * sdb_store_fetch_timeseries:
306 * Fetch the time-series described by the specified host's metric and
307 * serialize it as JSON into the provided string buffer.
308 *
309 * Returns:
310 * - 0 on success
311 * - a negative value else
312 */
313 int
314 sdb_store_fetch_timeseries(const char *hostname, const char *metric,
315 sdb_timeseries_opts_t *opts, sdb_strbuf_t *buf);
317 /*
318 * sdb_store_get_child:
319 * Retrieve a host's child object of the specified type and name. The
320 * reference count of the child object will be incremented before returning
321 * it. The caller is responsible for releasing the object once it's no longer
322 * used.
323 *
324 * Returns:
325 * - the child object on success
326 * - NULL else
327 */
328 sdb_store_obj_t *
329 sdb_store_get_child(sdb_store_obj_t *host, int type, const char *name);
331 /*
332 * sdb_store_get_field:
333 * Get the value of a stored object's queryable field. The caller is
334 * responsible for freeing any dynamically allocated memory possibly stored in
335 * the returned value. If 'res' is NULL, the function will return whether the
336 * field exists.
337 *
338 * Note: Retrieving the backend this way is not currently supported.
339 *
340 * Returns:
341 * - 0 on success
342 * - a negative value else
343 */
344 int
345 sdb_store_get_field(sdb_store_obj_t *obj, int field, sdb_data_t *res);
347 /*
348 * sdb_store_get_attr:
349 * Get the value of a stored object's attribute. The caller is responsible for
350 * freeing any dynamically allocated memory possibly stored in the returned
351 * value. If 'res' is NULL, the function will return whether the attribute
352 * exists. If specified, only attributes matching the filter will be
353 * considered.
354 *
355 * Returns:
356 * - 0 if the attribute exists
357 * - a negative value else
358 */
359 int
360 sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
361 sdb_store_matcher_t *filter);
363 /*
364 * Querying a store:
365 *
366 * - Query interface: A query is a formal description of an interaction with
367 * the store. It can be used, both, for read and write access. The query is
368 * described by its abstract syntax tree (AST). The parser package provides
369 * means to parse a string (SysQL) representation of the query into an AST.
370 *
371 * - Matcher / expression interface: This low-level interface provides direct
372 * control over how to access the store. It is used by the query
373 * implementation internally and can only be used for read access.
374 */
376 /*
377 * sdb_store_query_t:
378 * A parsed query readily prepared for execution.
379 */
380 struct sdb_store_query;
381 typedef struct sdb_store_query sdb_store_query_t;
383 /*
384 * sdb_store_query_prepare:
385 * Prepare the query described by 'ast' for execution in a store.
386 *
387 * Returns:
388 * - a store query on success
389 * - NULL else
390 */
391 sdb_store_query_t *
392 sdb_store_query_prepare(sdb_ast_node_t *ast);
394 /*
395 * sdb_store_query_prepare_matcher:
396 * Prepare the logical expression described by 'ast' for execution as a store
397 * matcher.
398 *
399 * Returns:
400 * - a matcher on success
401 * - NULL else
402 */
403 sdb_store_matcher_t *
404 sdb_store_query_prepare_matcher(sdb_ast_node_t *ast);
406 /*
407 * sdb_store_query_execute:
408 * Execute a previously prepared query. The query result will be written to
409 * 'buf' and any errors to 'errbuf'.
410 *
411 * Returns:
412 * - the result type (to be used by the server reply)
413 * - a negative value on error
414 */
415 int
416 sdb_store_query_execute(sdb_store_query_t *m,
417 sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
419 /*
420 * sdb_store_expr_create:
421 * Creates an arithmetic expression implementing the specified operator on the
422 * specified left and right operand.
423 *
424 * Returns:
425 * - an expression object on success
426 * - NULL else
427 */
428 sdb_store_expr_t *
429 sdb_store_expr_create(int op, sdb_store_expr_t *left, sdb_store_expr_t *right);
431 /*
432 * sdb_store_expr_typed:
433 * Creates an expression which evaluates in the context of an object's sibling
434 * as specified by the given type.
435 *
436 * Returns:
437 * - an expression object on success
438 * - NULL else
439 */
440 sdb_store_expr_t *
441 sdb_store_expr_typed(int typ, sdb_store_expr_t *expr);
443 /*
444 * sdb_store_expr_fieldvalue:
445 * Creates an expression which evaluates to the value of the specified
446 * queryable field of a stored object.
447 *
448 * Returns:
449 * - an expression object on success
450 * - NULL else
451 */
452 sdb_store_expr_t *
453 sdb_store_expr_fieldvalue(int field);
455 /*
456 * sdb_store_expr_attrvalue:
457 * Creates an expression which evaluates to the value of the specified
458 * attribute of a stored object. Evaluates to a NULL value if the attribute
459 * does not exist.
460 *
461 * Returns:
462 * - an expression object on success
463 * - NULL else
464 */
465 sdb_store_expr_t *
466 sdb_store_expr_attrvalue(const char *name);
468 /*
469 * sdb_store_expr_constvalue:
470 * Creates an expression which evaluates to the specified constant value.
471 *
472 * Returns:
473 * - an expression object on success
474 * - NULL else
475 */
476 sdb_store_expr_t *
477 sdb_store_expr_constvalue(const sdb_data_t *value);
479 /*
480 * sdb_store_expr_eval:
481 * Evaluate an expression for the specified stored object and stores the
482 * result in 'res'. The result's value will be allocated dynamically if
483 * necessary and, thus, should be free'd by the caller (e.g. using
484 * sdb_data_free_datum). The object may be NULL, in which case the expression
485 * needs to evaluate to a constant value. If specified, only objects matching
486 * the filter will be used during the evaluation.
487 *
488 * Returns:
489 * - 0 on success
490 * - a negative value else
491 */
492 int
493 sdb_store_expr_eval(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
494 sdb_data_t *res, sdb_store_matcher_t *filter);
496 /*
497 * sdb_store_expr_iterable:
498 * Check whether an expression, evaluated in the specified context (HOST,
499 * SERVICE, METRIC) is iterable, that is, if it may evaluate to multiple
500 * values.
501 */
502 bool
503 sdb_store_expr_iterable(sdb_store_expr_t *expr, int context);
505 /*
506 * sdb_store_expr_iter:
507 * Iterate over the elements of an iterable expression. sdb_store_expr_iter
508 * returns NULL if the expression is not iterable (for the specified object).
509 * See also sdb_store_expr_iterable.
510 *
511 * sdb_store_expr_iter_get_next returns NULL if there is no next element.
512 */
513 sdb_store_expr_iter_t *
514 sdb_store_expr_iter(sdb_store_expr_t *expr, sdb_store_obj_t *obj,
515 sdb_store_matcher_t *filter);
516 void
517 sdb_store_expr_iter_destroy(sdb_store_expr_iter_t *iter);
519 bool
520 sdb_store_expr_iter_has_next(sdb_store_expr_iter_t *iter);
521 sdb_data_t
522 sdb_store_expr_iter_get_next(sdb_store_expr_iter_t *iter);
524 /*
525 * sdb_store_dis_matcher:
526 * Creates a matcher matching the disjunction (logical OR) of two matchers.
527 */
528 sdb_store_matcher_t *
529 sdb_store_dis_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
531 /*
532 * sdb_store_con_matcher:
533 * Creates a matcher matching the conjunction (logical AND) of two matchers.
534 */
535 sdb_store_matcher_t *
536 sdb_store_con_matcher(sdb_store_matcher_t *left, sdb_store_matcher_t *right);
538 /*
539 * sdb_store_inv_matcher::
540 * Creates a matcher matching the inverse (logical NOT) of a matcher.
541 */
542 sdb_store_matcher_t *
543 sdb_store_inv_matcher(sdb_store_matcher_t *m);
545 /*
546 * sdb_store_any_matcher:
547 * Creates a matcher iterating over values of the first expression (which has
548 * to be iterable). It matches if *any* of those elements match 'm'. 'm' has
549 * to be an ary operation with the left operand unset.
550 */
551 sdb_store_matcher_t *
552 sdb_store_any_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
554 /*
555 * sdb_store_all_matcher:
556 * Creates a matcher iterating over values of the first expression (which has
557 * to be iterable). It matches if *all* of those elements match 'm'. 'm' has
558 * to be an ary operation with the left operand unset.
559 */
560 sdb_store_matcher_t *
561 sdb_store_all_matcher(sdb_store_expr_t *iter, sdb_store_matcher_t *m);
563 /*
564 * sdb_store_in_matcher:
565 * Creates a matcher which matches if the right value evaluates to an array
566 * value and the left value is included in that array. See sdb_data_inarray
567 * for more details.
568 */
569 sdb_store_matcher_t *
570 sdb_store_in_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
572 /*
573 * sdb_store_lt_matcher, sdb_store_le_matcher, sdb_store_eq_matcher,
574 * sdb_store_ge_matcher, sdb_store_gt_matcher:
575 * Create conditional matchers comparing the values of two expressions. The
576 * matcher matches if the left expression compres less than, less or equal
577 * than, equal to, not equal to, greater or equal than, or greater than the
578 * right expression.
579 */
580 sdb_store_matcher_t *
581 sdb_store_lt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
582 sdb_store_matcher_t *
583 sdb_store_le_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
584 sdb_store_matcher_t *
585 sdb_store_eq_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
586 sdb_store_matcher_t *
587 sdb_store_ne_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
588 sdb_store_matcher_t *
589 sdb_store_ge_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
590 sdb_store_matcher_t *
591 sdb_store_gt_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
593 /*
594 * sdb_store_regex_matcher:
595 * Creates a matcher which matches the string value the left expression
596 * evaluates to against the regular expression the right expression evaluates
597 * to. The right expression may either be a constant value regular expression
598 * or string or a dynamic value evaluating to a string. In the latter case,
599 * the string is compiled to a regex every time the matcher is executed.
600 */
601 sdb_store_matcher_t *
602 sdb_store_regex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
604 /*
605 * sdb_store_nregex_matcher:
606 * Creates a regex matcher just like sdb_store_regex_matcher except that it
607 * matches in case the regular expression does not match.
608 */
609 sdb_store_matcher_t *
610 sdb_store_nregex_matcher(sdb_store_expr_t *left, sdb_store_expr_t *right);
612 /*
613 * sdb_store_isnull_matcher:
614 * Creates a matcher matching NULL values.
615 */
616 sdb_store_matcher_t *
617 sdb_store_isnull_matcher(sdb_store_expr_t *expr);
619 /*
620 * sdb_store_istrue_matcher, sdb_store_isfalse_matcher:
621 * Creates a matcher matching boolean values.
622 */
623 sdb_store_matcher_t *
624 sdb_store_istrue_matcher(sdb_store_expr_t *expr);
625 sdb_store_matcher_t *
626 sdb_store_isfalse_matcher(sdb_store_expr_t *expr);
628 /*
629 * sdb_store_matcher_matches:
630 * Check whether the specified matcher matches the specified store object. If
631 * specified, the filter will be used to preselect objects for further
632 * evaluation. It is applied to any object that's used during the evaluation
633 * of the matcher. Only those objects matching the filter will be considered.
634 *
635 * Note that the filter is applied to all object types (hosts, service,
636 * metric, attribute). Thus, any object-specific matchers are mostly unsuited
637 * for this purpose and, if used, may result in unexpected behavior.
638 *
639 * Returns:
640 * - 1 if the object matches
641 * - 0 else
642 */
643 int
644 sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
645 sdb_store_matcher_t *filter);
647 /*
648 * sdb_store_matcher_op_cb:
649 * Callback constructing a matcher operator.
650 */
651 typedef sdb_store_matcher_t *(*sdb_store_matcher_op_cb)
652 (sdb_store_expr_t *, sdb_store_expr_t *);
654 /*
655 * sdb_store_parse_matcher_op:
656 * Parse a matcher operator and return a constructor for the respective
657 * matcher.
658 *
659 * Returns:
660 * - matcher operator constructor on success
661 * - NULL else
662 */
663 sdb_store_matcher_op_cb
664 sdb_store_parse_matcher_op(const char *op);
666 /*
667 * sdb_store_parse_object_type:
668 * Parse the type name of a stored object.
669 *
670 * Returns:
671 * - the object type on success
672 * - a negative value else
673 */
674 int
675 sdb_store_parse_object_type(const char *name);
677 /*
678 * sdb_store_parse_object_type_plural:
679 * Parse the type name (plural) of a stored object.
680 *
681 * Returns:
682 * - the object type on success
683 * - a negative value else
684 */
685 int
686 sdb_store_parse_object_type_plural(const char *name);
688 /*
689 * sdb_store_parse_field_name:
690 * Parse the name of a stored object's queryable field.
691 *
692 * Returns:
693 * - the field id on success
694 * - a negative value else
695 */
696 int
697 sdb_store_parse_field_name(const char *name);
699 /*
700 * sdb_store_lookup_cb:
701 * Lookup callback. It is called for each matching object when looking up data
702 * in the store passing on the lookup filter and the specified user-data. The
703 * lookup aborts early if the callback returns non-zero.
704 */
705 typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj,
706 sdb_store_matcher_t *filter, void *user_data);
708 /*
709 * sdb_store_scan:
710 * Look up objects of the specified type in the store. The specified callback
711 * function is called for each object in the store matching 'm'. The function
712 * performs a full scan of all objects stored in the database. If specified,
713 * the filter will be used to preselect objects for further evaluation. See
714 * the description of 'sdb_store_matcher_matches' for details.
715 *
716 * Returns:
717 * - 0 on success
718 * - a negative value else
719 */
720 int
721 sdb_store_scan(int type, sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
722 sdb_store_lookup_cb cb, void *user_data);
724 /*
725 * Flags for JSON formatting.
726 */
727 enum {
728 SDB_WANT_ARRAY = 1 << 0,
729 };
731 /*
732 * sdb_store_json_formatter:
733 * Create a JSON formatter for the specified object types writing to the
734 * specified buffer.
735 */
736 sdb_store_json_formatter_t *
737 sdb_store_json_formatter(sdb_strbuf_t *buf, int type, int flags);
739 /*
740 * sdb_store_json_emit:
741 * Serialize a single object to JSON adding it to the string buffer associated
742 * with the formatter object. The serialized object will not include
743 * attributes or any child objects. Instead, call the function again for each
744 * of those objects. All attributes have to be emitted before any other
745 * children types. Use sdb_store_json_emit_full() to emit a full (filtered)
746 * object.
747 *
748 * Note that the output might not be valid JSON before calling
749 * sdb_store_json_finish().
750 *
751 * Returns:
752 * - 0 on success
753 * - a negative value else
754 */
755 int
756 sdb_store_json_emit(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj);
758 /*
759 * sdb_store_json_emit_full:
760 * Serialize a single object including it's attributes and all children to
761 * JSON, adding it to the string buffer associated with the formatter object.
762 * The filter, if specified, is applied to each attribute and child object.
763 * Only matching objects will be included in the output.
764 *
765 * Note that the output might not be valid JSON before calling
766 * sdb_store_json_finish().
767 *
768 * Returns:
769 * - 0 on success
770 * - a negative value else
771 */
772 int
773 sdb_store_json_emit_full(sdb_store_json_formatter_t *f, sdb_store_obj_t *obj,
774 sdb_store_matcher_t *filter);
776 /*
777 * sdb_store_json_finish:
778 * Finish the JSON output. This function has to be called once after emiting
779 * all objects.
780 */
781 int
782 sdb_store_json_finish(sdb_store_json_formatter_t *f);
784 #ifdef __cplusplus
785 } /* extern "C" */
786 #endif
788 #endif /* ! SDB_CORE_STORE_H */
790 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */