improve command registration

Eliminate duplicate code for linking commands into a list.

Adds a check to ensure the command does not already exist;
if it does, return that one instead of creating a duplicate.

diff --git a/src/helper/command.c b/src/helper/command.c
index 5ac5c3015d43c6b1b41a398b7c650baad9ddad47..f960127d8b9e20cdabecb999048fb95323d16dc4 100644 (file)
--- a/src/helper/command.c
+++ b/src/helper/command.c
@@ -191,13 +191,53 @@ static void command_helptext_add(Jim_Obj *cmd_list, const char *help)
 /* nice short description of source file */
 #define __THIS__FILE__ "command.c"
 
-command_t* register_command(command_context_t *context, command_t *parent, char *name, int (*handler)(struct command_context_s *context, char* name, char** args, int argc), enum command_mode mode, char *help)
+/**
+ * Find a command by name from a list of commands.
+ * @returns The named command if found, or NULL.
+ */
+static struct command_s *command_find(struct command_s **head, const char *name)
+{
+       assert(head);
+       for (struct command_s *cc = *head; cc; cc = cc->next)
+       {
+               if (strcmp(cc->name, name) == 0)
+                       return cc;
+       }
+       return NULL;
+}
+
+/**
+ * Add the command to the end of linked list.
+ * @returns Returns false if the named command already exists in the list.
+ * Returns true otherwise.
+ */
+static void command_add_child(struct command_s **head, struct command_s *c)
 {
-       command_t *c, *p;
+       assert(head);
+       if (NULL == *head)
+       {
+               *head = c;
+               return;
+       }
+       struct command_s *cc = *head;
+       while (cc->next) cc = cc->next;
+       cc->next = c;
+}
 
+command_t* register_command(command_context_t *context,
+               command_t *parent, char *name,
+               int (*handler)(struct command_context_s *context,
+                               char* name, char** args, int argc),
+               enum command_mode mode, char *help)
+{
        if (!context || !name)
                return NULL;
 
+       struct command_s **head = parent ? &parent->children : &context->commands;
+       struct command_s *c = command_find(head, name);
+       if (NULL != c)
+               return c;
+
        c = malloc(sizeof(command_t));
 
        c->name = strdup(name);
@@ -207,35 +247,7 @@ command_t* register_command(command_context_t *context, command_t *parent, char
        c->mode = mode;
        c->next = NULL;
 
-       /* place command in tree */
-       if (parent)
-       {
-               if (parent->children)
-               {
-                       /* find last child */
-                       for (p = parent->children; p && p->next; p = p->next);
-                       if (p)
-                               p->next = c;
-               }
-               else
-               {
-                       parent->children = c;
-               }
-       }
-       else
-       {
-               if (context->commands)
-               {
-                       /* find last command */
-                       for (p = context->commands; p && p->next; p = p->next);
-                       if (p)
-                               p->next = c;
-               }
-               else
-               {
-                       context->commands = c;
-               }
-       }
+       command_add_child(head, c);
 
        command_helptext_add(command_name_list(c), help);