store: Let JSON serializers support (object) filters.

[sysdb.git] / src / include / core / store.h

diff --git a/src/include/core/store.h b/src/include/core/store.h
index 574b01ed262adcfd88d2a6be63afdff7285300a9..494f8d648c241834100c56a29560b6d58fd5ca6f 100644 (file)
--- a/src/include/core/store.h
+++ b/src/include/core/store.h
@@ -53,7 +53,6 @@ enum {
                : ((t) == SDB_SERVICE) ? "service" \
                : ((t) == SDB_ATTRIBUTE) ? "attribute" : "unknown")
 
-
 /*
  * sdb_store_obj_t represents the super-class of any object stored in the
  * database. It inherits from sdb_object_t and may safely be cast to a generic
@@ -62,6 +61,22 @@ enum {
 struct sdb_store_obj;
 typedef struct sdb_store_obj sdb_store_obj_t;
 
+/*
+ * Queryable fields of a stored object.
+ */
+enum {
+       SDB_FIELD_LAST_UPDATE = 1, /* datetime */
+       SDB_FIELD_AGE,             /* datetime */
+       SDB_FIELD_INTERVAL,        /* datetime */
+       SDB_FIELD_BACKEND,         /* string */
+};
+
+#define SDB_FIELD_TO_NAME(f) \
+       (((f) == SDB_FIELD_LAST_UPDATE) ? "last-update" \
+               : ((f) == SDB_FIELD_AGE) ? "age" \
+               : ((f) == SDB_FIELD_INTERVAL) ? "interval" \
+               : ((f) == SDB_FIELD_BACKEND) ? "backend" : "unknown")
+
 /*
  * sdb_store_clear:
  * Clear the entire store and remove all stored objects.
@@ -224,6 +239,15 @@ typedef struct sdb_store_cond sdb_store_cond_t;
 sdb_store_cond_t *
 sdb_store_attr_cond(const char *name, sdb_store_expr_t *expr);
 
+/*
+ * sdb_store_obj_cond:
+ * Creates a conditional based on queryable object fields. The respective
+ * field of *any* object type is compared against the value the expression
+ * evaluates to.
+ */
+sdb_store_cond_t *
+sdb_store_obj_cond(int field, sdb_store_expr_t *expr);
+
 /*
  * Store matchers may be used to lookup hosts from the store based on their
  * various attributes. Service and attribute matchers are applied to a host's
@@ -316,14 +340,22 @@ sdb_store_inv_matcher(sdb_store_matcher_t *m);
 
 /*
  * sdb_store_matcher_matches:
- * Check whether the specified matcher matches the specified store object.
+ * Check whether the specified matcher matches the specified store object. If
+ * specified, the filter will be used to preselect objects for further
+ * evaluation. It is applied to any object that's used during the evaluation
+ * of the matcher. Only those objects matching the filter will be considered.
+ *
+ * Note that the filter is applied to all object types (hosts, service,
+ * attribute). Thus, any object-specific matchers are mostly unsuited for this
+ * purpose and, if used, may result in unexpected behavior.
  *
  * Returns:
  *  - 1 if the object matches
  *  - 0 else
  */
 int
-sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj);
+sdb_store_matcher_matches(sdb_store_matcher_t *m, sdb_store_obj_t *obj,
+               sdb_store_matcher_t *filter);
 
 /*
  * sdb_store_matcher_tostring:
@@ -344,15 +376,17 @@ typedef int (*sdb_store_lookup_cb)(sdb_store_obj_t *obj, void *user_data);
  * sdb_store_scan:
  * Look up objects in the store. The specified callback function is called for
  * each object in the store matching 'm'. The function performs a full scan of
- * all hosts stored in the database.
+ * all hosts stored in the database. If specified, the filter will be used to
+ * preselect objects for further evaluation. See the description of
+ * 'sdb_store_matcher_matches' for details.
  *
  * Returns:
  *  - 0 on success
  *  - a negative value else
  */
 int
-sdb_store_scan(sdb_store_matcher_t *m, sdb_store_lookup_cb cb,
-               void *user_data);
+sdb_store_scan(sdb_store_matcher_t *m, sdb_store_matcher_t *filter,
+               sdb_store_lookup_cb cb, void *user_data);
 
 /*
  * Flags for serialization functions.
@@ -371,26 +405,31 @@ enum {
 /*
  * sdb_store_tojson:
  * Serialize the entire store to JSON and append the result to the specified
- * buffer.
+ * buffer. If specified, only objects matching the filter will be included in
+ * the result (see sdb_store_host_tojson for details).
  *
  * Returns:
  *  - 0 on success
  *  - a negative value on error
  */
 int
-sdb_store_tojson(sdb_strbuf_t *buf, int flags);
+sdb_store_tojson(sdb_strbuf_t *buf, sdb_store_matcher_t *filter, int flags);
 
 /*
  * sdb_store_host_tojson:
  * Serialize a host object to JSON and append the result to the specified
- * buffer.
+ * buffer. If specified, only objects matching the filter will be included in
+ * the result. The filter is applied to each object individually and, thus,
+ * should not be of any object-type specific kind. If the filter rejects the
+ * host object, the function returns success but leaves the buffer unmodified.
  *
  * Returns:
  *  - 0 on success
  *  - a negative value on error
  */
 int
-sdb_store_host_tojson(sdb_store_obj_t *host, sdb_strbuf_t *buf, int flags);
+sdb_store_host_tojson(sdb_store_obj_t *host, sdb_strbuf_t *buf,
+               sdb_store_matcher_t *filter, int flags);
 
 /*
  * sdb_store_iter_cb: