kenmirrors/asterisk
1
0
Fork 0
mirror of https://github.com/asterisk/asterisk.git synced 2025-10-31 02:37:10 +00:00
Code Issues Packages Projects Releases Wiki Activity

Better explained the depths of reference stealing.

Browse Source 
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@387803 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
David M. Lee
2013-05-07 18:12:26 +00:00
parent 570d0c3139
commit 737a45f2f7
1 changed files with 48 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
include/asterisk/json.h
View File

@@ -24,9 +24,54 @@
* \brief Asterisk JSON abstraction layer.
* \since 12.0.0
*
* This is a very thin wrapper around the Jansson API. For more details on it, see its
* docs at http://www.digip.org/jansson/doc/2.4/apiref.html.
* This is a very thin wrapper around the Jansson API. For more details on it,
* see its docs at http://www.digip.org/jansson/doc/2.4/apiref.html.
*
* Rather than provide the multiple ways of doing things that the Jansson API
* does, the Asterisk wrapper is always reference-stealing, and always NULL
* safe.
*
* And by always, I mean that the reference is stolen even if the function
* fails. This avoids lots of conditional logic, and also avoids having to track
* zillions of local variables when building complex JSON objects. You can
* instead chain \c ast_json_* calls together safely and only worry about
* cleaning up the root object.
*
* In the cases where you have a need to introduce intermediate objects, just
* wrap them with json_ref() when passing them to other \c ast_json_*()
* functions.
*
* \code
* // Example of how to use the Asterisk JSON API
* static struct ast_json *foo(void) {
* RAII_VAR(struct ast_json *, array, NULL, ast_json_unref);
* RAII_VAR(struct ast_json *, obj, NULL, ast_json_unref);
* int i, res;
*
* array = ast_json_array_create();
* if (!array) { return NULL; }
*
* for (i = 0; i < 10; ++i) {
* // NULL safety and object stealing means calls can
* // be chained together directly.
* res = ast_json_array_append(array,
* ast_json_integer_create(i));
* if (res != 0) { return NULL; }
* }
*
* obj = ast_json_object_create();
* if (!obj) { return NULL; }
*
* // If you already have an object reference, ast_json_ref()
* // can be used inline to bump the ref before passing it along
* // to a ref-stealing call
* res = ast_json_object_set(obj, "foo", ast_json_ref(array));
* if (!res) { return NULL; }
*
* return obj;
* }
* \endcode
*
* \author David M. Lee, II <dlee@digium.com>
*/