monitor: split off monitor_data_init()

In qmp_human_monitor_command(), the monitor need to initialized for
basic functionalities, and later more init code will be added, so
split off this function. Note that it is different with QMP mode
monitor which accept json string from monitor's input,
qmp_human_monitor_command() retrieve the human style command from
QMP input, then send the command to a normal mode monitor.
Signed-off-by: NWenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

monitor.c

@@ -683,14 +683,24 @@ static int do_qmp_capabilities(Monitor *mon, const QDict *params,
 
 static void handle_user_command(Monitor *mon, const char *cmdline);
 
+static void monitor_data_init(Monitor *mon)
+{
+    memset(mon, 0, sizeof(Monitor));
+    mon->outbuf = qstring_new();
+}
+
+static void monitor_data_destroy(Monitor *mon)
+{
+    QDECREF(mon->outbuf);
+}
+
 char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
                                 int64_t cpu_index, Error **errp)
 {
     char *output = NULL;
     Monitor *old_mon, hmp;
 
-    memset(&hmp, 0, sizeof(hmp));
-    hmp.outbuf = qstring_new();
+    monitor_data_init(&hmp);
     hmp.skip_flush = true;
 
     old_mon = cur_mon;
@@ -716,7 +726,7 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
     }
 
 out:
-    QDECREF(hmp.outbuf);
+    monitor_data_destroy(&hmp);
     return output;
 }
 
@@ -4767,8 +4777,8 @@ void monitor_init(CharDriverState *chr, int flags)
         is_first_init = 0;
     }
 
-    mon = g_malloc0(sizeof(*mon));
-    mon->outbuf = qstring_new();
+    mon = g_malloc(sizeof(*mon));
+    monitor_data_init(mon);
 
     mon->chr = chr;
     mon->flags = flags;