The Tor Browser: security/nss/lib/base/list.c@b8a032363ba2 (annotated)

security/nss/lib/base/list.c@b8a032363ba2 (annotated)

security/nss/lib/base/list.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * list.c
  *
  * This contains the implementation of NSS's thread-safe linked list.
  */
 #ifndef BASE_H
 #include "base.h"
 #endif /* BASE_H */
 struct nssListElementStr {
     PRCList  link;
     void    *data;
 };
 typedef struct nssListElementStr nssListElement;
 struct nssListStr {
     NSSArena       *arena;
     PZLock         *lock;
     nssListElement *head;
     PRUint32        count;
     nssListCompareFunc compareFunc;
     nssListSortFunc    sortFunc;
     PRBool i_alloced_arena;
 };
 struct nssListIteratorStr {
     PZLock *lock;
     nssList *list;
     nssListElement *current;
 };
 #define NSSLIST_LOCK_IF(list) \
     if ((list)->lock) PZ_Lock((list)->lock)
 #define NSSLIST_UNLOCK_IF(list) \
     if ((list)->lock) PZ_Unlock((list)->lock)
 static PRBool
 pointer_compare(void *a, void *b)
 {
     return (PRBool)(a == b);
 }
 static nssListElement *
 nsslist_get_matching_element(nssList *list, void *data)
 {
     PRCList *link;
     nssListElement *node;
     node = list->head;
     if (!node) {
 	return NULL;
     }
     link = &node->link;
     while (node) {
 	/* using a callback slows things down when it's just compare ... */
 	if (list->compareFunc(node->data, data)) {
 	    break;
 	}
 	link = &node->link;
 	if (link == PR_LIST_TAIL(&list->head->link)) {
 	    node = NULL;
 	    break;
 	}
 	node = (nssListElement *)PR_NEXT_LINK(&node->link);
     }
     return node;
 }
 NSS_IMPLEMENT nssList *
 nssList_Create
 (
   NSSArena *arenaOpt,
   PRBool threadSafe
 )
 {
     NSSArena *arena;
     nssList *list;
     PRBool i_alloced;
     if (arenaOpt) {
 	arena = arenaOpt;
 	i_alloced = PR_FALSE;
     } else {
 	arena = nssArena_Create();
 	i_alloced = PR_TRUE;
     }
     if (!arena) {
 	return (nssList *)NULL;
     }
     list = nss_ZNEW(arena, nssList);
     if (!list) {
 	if (!arenaOpt) {
 	    NSSArena_Destroy(arena);
 	}
 	return (nssList *)NULL;
     }
     if (threadSafe) {
 	list->lock = PZ_NewLock(nssILockOther);
 	if (!list->lock) {
 	    if (arenaOpt) {
 		nss_ZFreeIf(list);
 	    } else {
 		NSSArena_Destroy(arena);
 	    }
 	    return (nssList *)NULL;
 	}
     }
     list->arena = arena;
     list->i_alloced_arena = i_alloced;
     list->compareFunc = pointer_compare;
     return list;
 }
 NSS_IMPLEMENT PRStatus
 nssList_Destroy(nssList *list)
 {
     if (!list->i_alloced_arena) {
 	nssList_Clear(list, NULL);
     }
     if (list->lock) {
 	(void)PZ_DestroyLock(list->lock);
     }
     if (list->i_alloced_arena) {
 	NSSArena_Destroy(list->arena);
 	list = NULL;
     }
     nss_ZFreeIf(list);
     return PR_SUCCESS;
 }
 NSS_IMPLEMENT void
 nssList_SetCompareFunction(nssList *list, nssListCompareFunc compareFunc)
 {
     list->compareFunc = compareFunc;
 }
 NSS_IMPLEMENT void
 nssList_SetSortFunction(nssList *list, nssListSortFunc sortFunc)
 {
     /* XXX if list already has elements, sort them */
     list->sortFunc = sortFunc;
 }
 NSS_IMPLEMENT nssListCompareFunc
 nssList_GetCompareFunction(nssList *list)
 {
     return list->compareFunc;
 }
 NSS_IMPLEMENT void
 nssList_Clear(nssList *list, nssListElementDestructorFunc destructor)
 {
     PRCList *link;
     nssListElement *node, *tmp;
     NSSLIST_LOCK_IF(list);
     node = list->head;
     list->head = NULL;
     while (node && list->count > 0) {
 	if (destructor) (*destructor)(node->data);
 	link = &node->link;
 	tmp = (nssListElement *)PR_NEXT_LINK(link);
 	PR_REMOVE_LINK(link);
 	nss_ZFreeIf(node);
 	node = tmp;
 	--list->count;
     }
     NSSLIST_UNLOCK_IF(list);
 }
 static PRStatus
 nsslist_add_element(nssList *list, void *data)
 {
     nssListElement *node = nss_ZNEW(list->arena, nssListElement);
     if (!node) {
 	return PR_FAILURE;
     }
     PR_INIT_CLIST(&node->link);
     node->data = data;
     if (list->head) {
 	if (list->sortFunc) {
 	    PRCList *link;
 	    nssListElement *currNode;
 	    currNode = list->head;
 	    /* insert in ordered list */
 	    while (currNode) {
 		link = &currNode->link;
 		if (list->sortFunc(data, currNode->data) <= 0) {
 		    /* new element goes before current node */
 		    PR_INSERT_BEFORE(&node->link, link);
 		    /* reset head if this is first */
 		    if (currNode == list->head) list->head = node;
 		    break;
 		}
 		if (link == PR_LIST_TAIL(&list->head->link)) {
 		    /* reached end of list, append */
 		    PR_INSERT_AFTER(&node->link, link);
 		    break;
 		}
 		currNode = (nssListElement *)PR_NEXT_LINK(&currNode->link);
 	    }
 	} else {
 	    /* not sorting */
 	    PR_APPEND_LINK(&node->link, &list->head->link);
 	}
     } else {
 	list->head = node;
     }
     ++list->count;
     return PR_SUCCESS;
 }
 NSS_IMPLEMENT PRStatus
 nssList_Add(nssList *list, void *data)
 {
     PRStatus nssrv;
     NSSLIST_LOCK_IF(list);
     nssrv = nsslist_add_element(list, data);
     NSSLIST_UNLOCK_IF(list);
     return PR_SUCCESS;
 }
 NSS_IMPLEMENT PRStatus
 nssList_AddUnique(nssList *list, void *data)
 {
     PRStatus nssrv;
     nssListElement *node;
     NSSLIST_LOCK_IF(list);
     node = nsslist_get_matching_element(list, data);
     if (node) {
 	/* already in, finish */
 	NSSLIST_UNLOCK_IF(list);
 	return PR_SUCCESS;
     }
     nssrv = nsslist_add_element(list, data);
     NSSLIST_UNLOCK_IF(list);
     return nssrv;
 }
 NSS_IMPLEMENT PRStatus
 nssList_Remove(nssList *list, void *data)
 {
     nssListElement *node;
     NSSLIST_LOCK_IF(list);
     node = nsslist_get_matching_element(list, data);
     if (node) {
 	if (node == list->head) {
 	    list->head = (nssListElement *)PR_NEXT_LINK(&node->link);
 	}
 	PR_REMOVE_LINK(&node->link);
 	nss_ZFreeIf(node);
 	if (--list->count == 0) {
 	    list->head = NULL;
 	}
     }
     NSSLIST_UNLOCK_IF(list);
     return PR_SUCCESS;
 }
 NSS_IMPLEMENT void *
 nssList_Get(nssList *list, void *data)
 {
     nssListElement *node;
     NSSLIST_LOCK_IF(list);
     node = nsslist_get_matching_element(list, data);
     NSSLIST_UNLOCK_IF(list);
     return (node) ? node->data : NULL;
 }
 NSS_IMPLEMENT PRUint32
 nssList_Count(nssList *list)
 {
     return list->count;
 }
 NSS_IMPLEMENT PRStatus
 nssList_GetArray(nssList *list, void **rvArray, PRUint32 maxElements)
 {
     nssListElement *node;
     PRUint32 i = 0;
     PR_ASSERT(maxElements > 0);
     node = list->head;
     if (!node) {
 	return PR_SUCCESS;
     }
     NSSLIST_LOCK_IF(list);
     while (node) {
 	rvArray[i++] = node->data;
 	if (i == maxElements) break;
 	node = (nssListElement *)PR_NEXT_LINK(&node->link);
 	if (node == list->head) {
 	    break;
 	}
     }
     NSSLIST_UNLOCK_IF(list);
     return PR_SUCCESS;
 }
 NSS_IMPLEMENT nssList *
 nssList_Clone(nssList *list)
 {
     nssList *rvList;
     nssListElement *node;
     rvList = nssList_Create(NULL, (list->lock != NULL));
     if (!rvList) {
 	return NULL;
     }
     NSSLIST_LOCK_IF(list);
     if (list->count > 0) {
 	node = list->head;
 	while (PR_TRUE) {
 	    nssList_Add(rvList, node->data);
 	    node = (nssListElement *)PR_NEXT_LINK(&node->link);
 	    if (node == list->head) {
 		break;
 	    }
 	}
     }
     NSSLIST_UNLOCK_IF(list);
     return rvList;
 }
 NSS_IMPLEMENT nssListIterator *
 nssList_CreateIterator(nssList *list)
 {
     nssListIterator *rvIterator;
     rvIterator = nss_ZNEW(NULL, nssListIterator);
     if (!rvIterator) {
 	return NULL;
     }
     rvIterator->list = nssList_Clone(list);
     if (!rvIterator->list) {
 	nss_ZFreeIf(rvIterator);
 	return NULL;
     }
     rvIterator->current = rvIterator->list->head;
     if (list->lock) {
 	rvIterator->lock = PZ_NewLock(nssILockOther);
 	if (!rvIterator->lock) {
 	    nssList_Destroy(rvIterator->list);
 	    nss_ZFreeIf(rvIterator);
 	    rvIterator = NULL;
 	}
     }
     return rvIterator;
 }
 NSS_IMPLEMENT void
 nssListIterator_Destroy(nssListIterator *iter)
 {
     if (iter->lock) {
 	(void)PZ_DestroyLock(iter->lock);
     }
     nssList_Destroy(iter->list);
     nss_ZFreeIf(iter);
 }
 NSS_IMPLEMENT void *
 nssListIterator_Start(nssListIterator *iter)
 {
     NSSLIST_LOCK_IF(iter);
     if (iter->list->count == 0) {
 	return NULL;
     }
     iter->current = iter->list->head;
     return iter->current->data;
 }
 NSS_IMPLEMENT void *
 nssListIterator_Next(nssListIterator *iter)
 {
     nssListElement *node;
     PRCList *link;
     if (iter->list->count == 1 || iter->current == NULL) {
 	/* Reached the end of the list.  Don't change the state, force to
 	 * user to call nssList_Finish to clean up.
 	 */
 	return NULL;
     }
     node = (nssListElement *)PR_NEXT_LINK(&iter->current->link);
     link = &node->link;
     if (link == PR_LIST_TAIL(&iter->list->head->link)) {
 	/* Signal the end of the list. */
 	iter->current = NULL;
 	return node->data;
     }
     iter->current = node;
     return node->data;
 }
 NSS_IMPLEMENT PRStatus
 nssListIterator_Finish(nssListIterator *iter)
 {
     iter->current = iter->list->head;
     return (iter->lock) ? PZ_Unlock(iter->lock) : PR_SUCCESS;
 }

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security/nss/lib/base/list.c@b8a032363ba2 (annotated)

security/nss/lib/base/list.c