From 0ff535b6f36e5d057eb9bbfef18bafff966df637 Mon Sep 17 00:00:00 2001
From: Krzysztof Opasiak <k.opasiak@samsung.com>
Date: Wed, 31 May 2017 12:32:10 +0200
Subject: [PATCH] Add helpers for bson manipulation

Change-Id: Iad2cefd42c3322a7d7d9a4fd66f3f939e88d87c7
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
---
 src/util/common.c | 33 +++++++++++++++++++++++++++++++++
 src/util/common.h | 30 ++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/src/util/common.c b/src/util/common.c
index 359ab87..3d3c910 100644
--- a/src/util/common.c
+++ b/src/util/common.c
@@ -25,3 +25,36 @@ GENERATE_BSON_APPEND_STRUCT(timespec,
 							bson_append_long(out, "sec", data->tv_sec);
 							bson_append_long(out, "nsec", data->tv_nsec);
 							)
+
+int bson_fill_empty(bson *b)
+{
+	int ret;
+
+	ret = faultd_bson_safe_init_size(b, BSON_EMPTY_SIZE);
+	if (ret != BSON_OK)
+		goto out;
+
+	ret = bson_finish(b);
+	if (ret != BSON_OK)
+		goto destroy;
+
+	return 0;
+destroy:
+	bson_destroy(b);
+out:
+	return -ENOMEM;
+}
+
+char *bson_get_string(bson *b, char *fieldpath)
+{
+	bson_iterator it;
+	int ret;
+
+	BSON_ITERATOR_INIT(&it, b);
+
+	ret = bson_find_fieldpath_value(fieldpath, &it);
+	if (ret == BSON_EOO || ret != BSON_STRING)
+		return NULL;
+
+	return (char *)bson_iterator_string(&it);
+}
diff --git a/src/util/common.h b/src/util/common.h
index b874a43..6ae1cc2 100644
--- a/src/util/common.h
+++ b/src/util/common.h
@@ -22,6 +22,7 @@
 #include <ejdb/bson.h>
 #include <stdlib.h>
 #include <time.h>
+#include <errno.h>
 
 #define ARRAY_SIZE(a) (sizeof(a)/sizeof(*a))
 
@@ -62,4 +63,33 @@ static inline void freep(void *p)
 
 DECLARE_BSON_APPEND_STRUCT(timespec);
 
+#define BSON_EMPTY_SIZE (4 /* len */ + 1 /* \0 */)
+
+#define BSON_INITIAL_BUFFER_SIZE 128
+
+static inline int faultd_bson_safe_init_size(bson *b, int size)
+{
+	int ret;
+	/*
+	 * TODO:
+	 * For now ejdb does not provide bson constructors
+	 * which return error if memory allocation fails.
+	 * This wrapper should be removed when such functions
+	 * become available.
+	 */
+	bson_init_size(b, 0);
+	ret = bson_ensure_space(b, size);
+	if (ret != BSON_OK)
+		bson_destroy(b);
+
+	return ret;
+}
+
+#define faultd_bson_safe_init(b)				\
+	faultd_bson_safe_init_size(b, BSON_INITIAL_BUFFER_SIZE)
+
+int bson_fill_empty(bson *b);
+
+char *bson_get_string(bson *b, char *fieldpath);
+
 #endif /* FAULTD_COMMON_H */
-- 
2.34.1