[libvirt] [PATCHv2 06/13] util: json: add helper to iterate JSON object key=value pairs

This helper eases iterating all key=value pairs stored in a JSON object. Usually we pick only certain known keys from a JSON object, but this will allow to walk complete objects and have the callback act on those. --- Notes: Version 2:- - fixed typo in commit message - ACKed by Eric src/libvirt_private.syms | 1 + src/util/virjson.c | 33 +++++++++++++++++++++++++++++++++ src/util/virjson.h | 8 ++++++++ 3 files changed, 42 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index ab32eaa..cf5ccaf 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1550,6 +1550,7 @@ virJSONValueObjectAppendNumberUlong; virJSONValueObjectAppendString; virJSONValueObjectCreate; virJSONValueObjectCreateVArgs; +virJSONValueObjectForeachKeyValue; virJSONValueObjectGet; virJSONValueObjectGetBoolean; virJSONValueObjectGetKey; diff --git a/src/util/virjson.c b/src/util/virjson.c index 1bb2653..c8d761f 100644 --- a/src/util/virjson.c +++ b/src/util/virjson.c @@ -1200,6 +1200,39 @@ virJSONValueObjectIsNull(virJSONValuePtr object, } +/** + * virJSONValueObjectForeachKeyValue: + * @object: JSON object to iterate + * @cb: callback to call on key-value pairs contained in the object + * @opaque: generic data for the callback + * + * Iterates all key=value pairs in @object. Iteration breaks if @cb returns + * negative value. + * + * Returns 0 if all elements were iterated, -2 if @cb returned negative value + * during iteration and -1 on generic errors. + */ +int +virJSONValueObjectForeachKeyValue(virJSONValuePtr object, + virJSONValueObjectIteratorFunc cb, + void *opaque) +{ + size_t i; + + if (object->type != VIR_JSON_TYPE_OBJECT) + return -1; + + for (i = 0; i < object->data.object.npairs; i++) { + virJSONObjectPairPtr elem = object->data.object.pairs + i; + + if (cb(elem->key, elem->value, opaque) < 0) + return -2; + } + + return 0; +} + + #if WITH_YAJL static int virJSONParserInsertValue(virJSONParserPtr parser, diff --git a/src/util/virjson.h b/src/util/virjson.h index 57010b0..9bb7461 100644 --- a/src/util/virjson.h +++ b/src/util/virjson.h @@ -157,4 +157,12 @@ virJSONValuePtr virJSONValueFromString(const char *jsonstring); char *virJSONValueToString(virJSONValuePtr object, bool pretty); +typedef int (*virJSONValueObjectIteratorFunc)(const char *key, + const virJSONValue *value, + void *opaque); + +int virJSONValueObjectForeachKeyValue(virJSONValuePtr object, + virJSONValueObjectIteratorFunc cb, + void *opaque); + #endif /* __VIR_JSON_H_ */ -- 2.2.2