Provide custom logging hook

Hello, proud Zookeeper maintainers!

I incoporated the zookeeper C client API in a quite large code base. The result is fine, everything works as expected but the logs. Our code already manages its log traces via one API, the GLib-2.0 logging features. The current "FILE*" based logging of the C client is not suitable for us.

I propose to integrate a minimal change that would allows me to plug ZK's output on any other : a simple logging hook. I pasted below the patch I propose.

What do you think about ?

diff -r -U3 zookeeper-3.4.6/src/c/include/zookeeper_log.h zookeeper-3.4.6-new/src/c/include/zookeeper_log.h
— zookeeper-3.4.6/src/c/include/zookeeper_log.h 2014-02-20 11:14:08.000000000 +0100
+++ zookeeper-3.4.6-new/src/c/include/zookeeper_log.h 2014-11-24 13:36:21.088124921 +0100
@@ -44,6 +44,10 @@

FILE* getLogStream();

+typedef void (zk_hook_log) (ZooLogLevel, int, const char*, const char *);
+
+void zoo_set_log_hook (zk_hook_log *hook);
+
#ifdef __cplusplus
}
#endif

diff -r -U3 zookeeper-3.4.6/src/c/src/zk_log.c zookeeper-3.4.6-new/src/c/src/zk_log.c
— zookeeper-3.4.6/src/c/src/zk_log.c 2014-02-20 11:14:09.000000000 +0100
+++ zookeeper-3.4.6-new/src/c/src/zk_log.c 2014-11-24 14:28:46.151503385 +0100
@@ -122,9 +122,17 @@
return now_str;
}

+static zk_hook_log *log_hook = NULL;
+void zoo_set_log_hook (zk_hook_log *hook)
+

{ + log_hook = hook; +}

+
void log_message(ZooLogLevel curLevel,int line,const char* funcName,
const char* message)
{
+ if (log_hook) return (*log_hook)(curLevel, line, funcName, message);
+
static const char* dbgLevelStr[]=

{"ZOO_INVALID","ZOO_ERROR","ZOO_WARN", "ZOO_INFO","ZOO_DEBUG"}

;
static pid_t pid=0;