List improvements from kpfleming (bugs #3166,#3140)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4629 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_sql_postgres.c

@@ -191,7 +191,7 @@ static int del_identifier(int identifier,int identifier_type) {
 		AST_LIST_TRAVERSE(headp,i,entries) {
 			if ((i->identifier==identifier) && 
 			    (i->identifier_type==identifier_type)) {
-				AST_LIST_REMOVE(headp,i,ast_PGSQL_id,entries);
+				AST_LIST_REMOVE(headp,i,entries);
 				free(i);
 				found=1;
 				break;

channel.c

@@ -673,7 +673,7 @@ void ast_channel_free(struct ast_channel *chan)
 	/* no need to lock the list, as the channel is already locked */
 	
 	while (!AST_LIST_EMPTY(headp)) {           /* List Deletion. */
-	            vardata = AST_LIST_REMOVE_HEAD(headp, ast_var_t, entries);
+	            vardata = AST_LIST_REMOVE_HEAD(headp, entries);
 /*	            printf("deleting var %s=%s\n",ast_var_name(vardata),ast_var_value(vardata)); */
 	            ast_var_delete(vardata);
 	}

include/asterisk/linkedlists.h

@@ -147,6 +147,50 @@ struct {								\
 #define AST_LIST_TRAVERSE(head,var,field) 				\
 	for((var) = (head)->first; (var); (var) = (var)->field.next)
 
+/*!
+  \brief Loops safely over (traverses) the entries in a list.
+  \param head This is a pointer to the list head structure
+  \param var This is the name of the variable that will hold a pointer to the
+  current list entry on each iteration. It must be declared before calling
+  this macro.
+  \param field This is the name of the field (declared using AST_LIST_ENTRY())
+  used to link entries of this list together.
+
+  This macro is used to safely loop over (traverse) the entries in a list. It
+  uses a \a for loop, and supplies the enclosed code with a pointer to each list
+  entry as it loops. It is typically used as follows:
+  \code
+  static AST_LIST_HEAD(entry_list, list_entry) entries;
+  ...
+  struct list_entry {
+  	...
+  	AST_LIST_ENTRY(list_entry) list;
+  }
+  ...
+  struct list_entry *current;
+  ...
+  AST_LIST_TRAVERSE_SAFE_BEGIN(&entries, current, list_entry, list) {
+     (do something with current here)
+  }
+  AST_LIST_TRAVERSE_SAFE_END
+  \endcode
+
+  It differs from AST_LIST_TRAVERSE in that the code inside the loop can modify
+  (or even free) the entry pointed to by the \a current pointer without affecting
+  the loop traversal.
+*/
+#define AST_LIST_TRAVERSE_SAFE_BEGIN(head, var, field) {				\
+	typeof((head)->first) __list_next;						\
+	for ((var) = (head)->first,  __list_next = (var) ? (var)->field.next : NULL;	\
+	     (var);									\
+	     (var) = __list_next,  __list_next = (var) ? (var)->field.next : NULL	\
+	    )
+
+/*!
+  \brief Closes a safe loop traversal block.
+ */
+#define AST_LIST_TRAVERSE_SAFE_END  }
+
 /*!
   \brief Initializes a list head structure.
   \param head This is a pointer to the list head structure
@@ -188,34 +232,32 @@ struct {								\
   \brief Inserts a list entry at the tail of a list.
   \param head This is a pointer to the list head structure
   \param elm This is a pointer to the entry to be inserted.
-  \param type This is the type of each list entry.
   \param field This is the name of the field (declared using AST_LIST_ENTRY())
   used to link entries of this list together.
  */
-#define AST_LIST_INSERT_TAIL(head, elm, type, field) do {             \
-      struct type *curelm = (head)->first;                            \
-      if(!curelm) {                                                   \
+#define AST_LIST_INSERT_TAIL(head, elm, field) do {		      \
+      typeof(elm) curelm = (head)->first;                             \
+      if (!curelm) {                                                  \
               AST_LIST_INSERT_HEAD(head, elm, field);                 \
       } else {                                                        \
-              while ( curelm->field.next!=NULL ) {                    \
+              while (curelm->field.next!=NULL) {                      \
                       curelm=curelm->field.next;                      \
               }                                                       \
-              AST_LIST_INSERT_AFTER(curelm,elm,field);                \
+              AST_LIST_INSERT_AFTER(curelm, elm, field);              \
       }                                                               \
 } while (0)
 
 /*!
   \brief Removes and returns the head entry from a list.
   \param head This is a pointer to the list head structure
-  \param type This is the type of each list entry.
   \param field This is the name of the field (declared using AST_LIST_ENTRY())
   used to link entries of this list together.
 
   Removes the head entry from the list, and returns a pointer to it. The
   forward-link pointer in the returned entry is \b not cleared.
  */
-#define AST_LIST_REMOVE_HEAD(head, type, field) ({				\
-		struct type *cur = (head)->first;				\
+#define AST_LIST_REMOVE_HEAD(head, field) ({    				\
+		typeof((head)->first) cur = (head)->first;			\
 		(head)->first = (head)->first->field.next;			\
 		cur;								\
 	})
@@ -224,17 +266,16 @@ struct {								\
   \brief Removes a specific entry from a list.
   \param head This is a pointer to the list head structure
   \param elm This is a pointer to the entry to be removed.
-  \param type This is the type of each list entry.
   \param field This is the name of the field (declared using AST_LIST_ENTRY())
   used to link entries of this list together.
   \warning The removed entry is \b not freed nor modified in any way.
  */
-#define AST_LIST_REMOVE(head, elm, type, field) do {			\
+#define AST_LIST_REMOVE(head, elm, field) do {			        \
 	if ((head)->first == (elm)) {					\
-		AST_LIST_REMOVE_HEAD((head), type, field);		\
+		AST_LIST_REMOVE_HEAD((head), field);			\
 	}								\
 	else {								\
-		struct type *curelm = (head)->first;			\
+		typeof(elm) curelm = (head)->first;			\
 		while( curelm->field.next != (elm) )			\
 			curelm = curelm->field.next;			\
 		curelm->field.next =					\

pbx.c

@@ -5052,7 +5052,7 @@ void pbx_builtin_setvar_helper(struct ast_channel *chan, char *name, char *value
 	AST_LIST_TRAVERSE (headp, newvariable, entries) {
 		if (strcasecmp(ast_var_name(newvariable), name) == 0) {
 			/* there is already such a variable, delete it */
-			AST_LIST_REMOVE(headp, newvariable, ast_var_t, entries);
+			AST_LIST_REMOVE(headp, newvariable, entries);
 			ast_var_delete(newvariable);
 			break;
 		}
@@ -5155,7 +5155,7 @@ void pbx_builtin_clear_globals(void)
 {
 	struct ast_var_t *vardata;
 	while (!AST_LIST_EMPTY(&globals)) {
-		vardata = AST_LIST_REMOVE_HEAD(&globals, ast_var_t, entries);
+		vardata = AST_LIST_REMOVE_HEAD(&globals, entries);
 		ast_var_delete(vardata);
 	}
 }

pbx/pbx_dundi.c

@@ -551,7 +551,7 @@ static int dundi_lookup_local(struct dundi_result *dr, struct dundi_mapping *map
 				AST_LIST_INSERT_HEAD(&headp, newvariable, entries);
 				pbx_substitute_variables_varshead(&headp, map->dest, dr[anscnt].dest, sizeof(dr[anscnt].dest));
 				while (!AST_LIST_EMPTY(&headp)) {           /* List Deletion. */
-					newvariable = AST_LIST_REMOVE_HEAD(&headp, ast_var_t, entries);
+					newvariable = AST_LIST_REMOVE_HEAD(&headp, entries);
 					ast_var_delete(newvariable);
 				}
 			} else

pbx/pbx_loopback.c

@@ -81,7 +81,7 @@ static char *loopback_helper(char *buf, int buflen, const char *exten, const cha
 	pbx_substitute_variables_varshead(&headp, data, buf, buflen);
 	/* Substitute variables */
 	while (!AST_LIST_EMPTY(&headp)) {           /* List Deletion. */
-		newvariable = AST_LIST_REMOVE_HEAD(&headp, ast_var_t, entries);
+		newvariable = AST_LIST_REMOVE_HEAD(&headp, entries);
 		ast_var_delete(newvariable);
 	}
 	return buf;