index 3722a7262d6aa773d4f3210e12217e7505d449f1..fb59c7c1ba5f8cf7c2d09e56295c74d6512d54e7 100644 (file)
--- a/src/include/core/store.h
+++ b/src/include/core/store.h
#include "core/data.h"
#include "core/time.h"
#include "core/timeseries.h"
+#include "parser/ast.h"
#include "utils/strbuf.h"
#include <stdbool.h>
SDB_FIELD_AGE, /* type: datetime */
SDB_FIELD_INTERVAL, /* type: datetime */
SDB_FIELD_BACKEND, /* type: array of strings */
+ SDB_FIELD_VALUE, /* attributes only; type: type of the value */
};
#define SDB_STORE_TYPE_TO_NAME(t) \
(((t) == SDB_HOST) ? "host" \
: ((f) == SDB_FIELD_LAST_UPDATE) ? "last-update" \
: ((f) == SDB_FIELD_AGE) ? "age" \
: ((f) == SDB_FIELD_INTERVAL) ? "interval" \
- : ((f) == SDB_FIELD_BACKEND) ? "backend" : "unknown")
+ : ((f) == SDB_FIELD_BACKEND) ? "backend" \
+ : ((f) == SDB_FIELD_VALUE) ? "value" \
+ : "unknown")
#define SDB_FIELD_TYPE(f) \
(((f) == SDB_FIELD_NAME) ? SDB_TYPE_STRING \
: ((f) == SDB_FIELD_AGE) ? SDB_TYPE_DATETIME \
: ((f) == SDB_FIELD_INTERVAL) ? SDB_TYPE_DATETIME \
: ((f) == SDB_FIELD_BACKEND) ? (SDB_TYPE_ARRAY | SDB_TYPE_STRING) \
+ : ((f) == SDB_FIELD_VALUE) ? -1 /* unknown */ \
: -1)
/*
sdb_store_get_attr(sdb_store_obj_t *obj, const char *name, sdb_data_t *res,
sdb_store_matcher_t *filter);
+/*
+ * Querying a store:
+ *
+ * - Query interface: A query is a formal description of an interaction with
+ * the store. It can be used, both, for read and write access. The query is
+ * described by its abstract syntax tree (AST). The parser package provides
+ * means to parse a string (SysQL) representation of the query into an AST.
+ *
+ * - Matcher / expression interface: This low-level interface provides direct
+ * control over how to access the store. It is used by the query
+ * implementation internally and can only be used for read access.
+ */
+
+/*
+ * sdb_store_query_t:
+ * A parsed query readily prepared for execution.
+ */
+struct sdb_store_query;
+typedef struct sdb_store_query sdb_store_query_t;
+
+/*
+ * sdb_store_query_prepare:
+ * Prepare the query described by 'ast' for execution in a store.
+ *
+ * Returns:
+ * - a store query on success
+ * - NULL else
+ */
+sdb_store_query_t *
+sdb_store_query_prepare(sdb_ast_node_t *ast);
+
+/*
+ * sdb_store_query_execute:
+ * Execute a previously prepared query. The query result will be written to
+ * 'buf' and any errors to 'errbuf'.
+ *
+ * Returns:
+ * - the result type (to be used by the server reply)
+ * - a negative value on error
+ */
+int
+sdb_store_query_execute(sdb_store_query_t *m,
+ sdb_strbuf_t *buf, sdb_strbuf_t *errbuf);
+
/*
* sdb_store_expr_create:
* Creates an arithmetic expression implementing the specified operator on the