core: optimize xxx_valid() functions: return immediately if pointer is NULL

src/core/wee-hook.c

@@ -344,6 +344,9 @@ hook_valid (struct t_hook *hook)
     int type;
     struct t_hook *ptr_hook;
 
+    if (!hook)
+        return 0;
+
     for (type = 0; type < HOOK_NUM_TYPES; type++)
     {
         for (ptr_hook = weechat_hooks[type]; ptr_hook;

src/core/wee-infolist.c

@@ -287,6 +287,9 @@ infolist_valid (struct t_infolist *infolist)
 {
     struct t_infolist *ptr_infolist;
 
+    if (!infolist)
+        return 0;
+
     for (ptr_infolist = weechat_infolists; ptr_infolist;
          ptr_infolist = ptr_infolist->next_infolist)
     {

src/plugins/irc/irc-channel.c

@@ -51,7 +51,7 @@ irc_channel_valid (struct t_irc_server *server, struct t_irc_channel *channel)
 {
     struct t_irc_channel *ptr_channel;
 
-    if (!server)
+    if (!server || !channel)
         return 0;
 
     for (ptr_channel = server->channels; ptr_channel;

src/plugins/irc/irc-nick.c

@@ -48,7 +48,7 @@ irc_nick_valid (struct t_irc_channel *channel, struct t_irc_nick *nick)
 {
     struct t_irc_nick *ptr_nick;
 
-    if (!channel)
+    if (!channel || !nick)
         return 0;
 
     for (ptr_nick = channel->nicks; ptr_nick; ptr_nick = ptr_nick->next_nick)

src/plugins/plugin-script.c

@@ -256,7 +256,7 @@ plugin_script_valid (struct t_plugin_script *scripts,
 {
     struct t_plugin_script *ptr_script;
 
-    if (!script)
+    if (!scripts || !script)
         return 0;
 
     for (ptr_script = scripts; ptr_script;