1 files changed, 415 insertions, 0 deletions
diff --git a/runtime/linkedlist.c b/runtime/linkedlist.c
new file mode 100644
index 0000000..7088737
--- /dev/null
+++ b/runtime/linkedlist.c
@@ -0,0 +1,415 @@
+/* linkedlist.c
+ * This file set implements a generic linked list object. It can be used
+ * wherever a linke list is required.
+ *
+ * NOTE: we do not currently provide a constructor and destructor for the
+ * object itself as we assume it will always be part of another strucuture.
+ * Having a pointer to it, I think, does not really make sense but costs
+ * performance. Consequently, there is is llInit() and llDestroy() and they
+ * do what a constructor and destructur do, except for creating the
+ * linkedList_t structure itself.
+ *
+ * File begun on 2007-07-31 by RGerhards
+ *
+ * Copyright (C) 2007-2012 Adiscon GmbH.
+ *
+ * This file is part of the rsyslog runtime library.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *       -or-
+ *       see COPYING.ASL20 in the source distribution
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "rsyslog.h"
+#include "linkedlist.h"
+
+
+/* Initialize an existing linkedList_t structure
+ * pKey destructor may be zero to take care of non-keyed lists.
+ */
+rsRetVal llInit(linkedList_t *pThis, rsRetVal (*pEltDestructor)(void*), rsRetVal (*pKeyDestructor)(void*),
+int (*pCmpOp)(void*,void*))
+{
+	assert(pThis != NULL);
+	assert(pEltDestructor != NULL);
+
+	pThis->pEltDestruct = pEltDestructor;
+	pThis->pKeyDestruct = pKeyDestructor;
+	pThis->cmpOp = pCmpOp;
+	pThis->pKey = NULL;
+	pThis->iNumElts = 0;
+	pThis->pRoot = NULL;
+	pThis->pLast = NULL;
+
+	return RS_RET_OK;
+};
+	
+
+/* llDestroyEltData - destroys a list element
+ * It is a separate function as the
+ * functionality is needed in multiple code-pathes.
+ */
+static rsRetVal llDestroyElt(linkedList_t *pList, llElt_t *pElt)
+{
+	DEFiRet;
+
+	assert(pList != NULL);
+	assert(pElt != NULL);
+
+	/* we ignore errors during destruction, as we need to try
+	 * free the element in any case.
+	 */
+	if(pElt->pData != NULL)
+		pList->pEltDestruct(pElt->pData);
+	if(pElt->pKey != NULL)
+		pList->pKeyDestruct(pElt->pKey);
+	free(pElt);
+	pList->iNumElts--; /* one less */
+
+	RETiRet;
+}
+
+
+/* llDestroy - destroys a COMPLETE linkedList
+ */
+rsRetVal llDestroy(linkedList_t *pThis)
+{
+	DEFiRet;
+	llElt_t *pElt;
+
+	assert(pThis != NULL);
+
+	pElt = pThis->pRoot;
+	while(pElt != NULL) {
+		/* keep the list structure in a consistent state as
+		 * the destructor bellow may reference it again
+		 */
+		pThis->pRoot = pElt->pNext;
+		if(pElt->pNext == NULL)
+			pThis->pLast = NULL;
+
+		/* we ignore errors during destruction, as we need to try
+		 * finish the linked list in any case.
+		 */
+		llDestroyElt(pThis, pElt);
+		pElt = pThis->pRoot;
+	}
+
+	RETiRet;
+}
+
+/* llDestroyRootElt - destroy the root element but otherwise
+ * keeps this list intact.  -- rgerhards, 2007-08-03
+ */
+rsRetVal llDestroyRootElt(linkedList_t *pThis)
+{
+	DEFiRet;
+	llElt_t *pPrev;
+	
+	if(pThis->pRoot == NULL) {
+		ABORT_FINALIZE(RS_RET_EMPTY_LIST);
+	}
+
+	pPrev = pThis->pRoot;
+	if(pPrev->pNext == NULL) {
+		/* it was the only list element */
+		pThis->pLast = NULL;
+		pThis->pRoot = NULL;
+	} else {
+		/* there are other list elements */
+		pThis->pRoot = pPrev->pNext;
+	}
+
+	CHKiRet(llDestroyElt(pThis, pPrev));
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* get next user data element of a linked list. The caller must also
+ * provide a "cookie" to the function. On initial call, it must be
+ * NULL. Other than that, the caller is not allowed to to modify the
+ * cookie. In the current implementation, the cookie is an actual
+ * pointer to the current list element, but this is nothing that the
+ * caller should rely on.
+ */
+rsRetVal llGetNextElt(linkedList_t *pThis, linkedListCookie_t *ppElt, void **ppUsr)
+{
+	llElt_t *pElt;
+	DEFiRet;
+
+	assert(pThis != NULL);
+	assert(ppElt != NULL);
+	assert(ppUsr != NULL);
+
+	pElt = *ppElt;
+
+	pElt = (pElt == NULL) ? pThis->pRoot : pElt->pNext;
+
+	if(pElt == NULL) {
+		iRet = RS_RET_END_OF_LINKEDLIST;
+	} else {
+		*ppUsr = pElt->pData;
+	}
+
+	*ppElt = pElt;
+
+	RETiRet;
+}
+
+
+/* return the key of an Elt
+ * rgerhards, 2007-09-11: note that ppDatea is actually a void**,
+ * but I need to make it a void* to avoid lots of compiler warnings.
+ * It will be converted later down in the code.
+ */
+rsRetVal llGetKey(llElt_t *pThis, void *ppData)
+{
+	assert(pThis != NULL);
+	assert(ppData != NULL);
+
+	*(void**) ppData = pThis->pKey;
+
+	return RS_RET_OK;
+}
+
+
+/* construct a new llElt_t
+ */
+static rsRetVal llEltConstruct(llElt_t **ppThis, void *pKey, void *pData)
+{
+	DEFiRet;
+	llElt_t *pThis;
+
+	assert(ppThis != NULL);
+
+	if((pThis = (llElt_t*) calloc(1, sizeof(llElt_t))) == NULL) {
+		ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
+	}
+
+	pThis->pKey = pKey;
+	pThis->pData = pData;
+
+finalize_it:
+	*ppThis = pThis;
+	RETiRet;
+}
+
+
+/* append a user element to the end of the linked list. This includes setting a key. If no
+ * key is desired, simply pass in a NULL pointer for it.
+ */
+rsRetVal llAppend(linkedList_t *pThis, void *pKey, void *pData)
+{
+	llElt_t *pElt;
+	DEFiRet;
+	
+	CHKiRet(llEltConstruct(&pElt, pKey, pData));
+
+	pThis->iNumElts++; /* one more */
+	if(pThis->pLast == NULL) {
+		pThis->pRoot = pElt;
+	} else {
+		pThis->pLast->pNext = pElt;
+	}
+	pThis->pLast = pElt;
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* unlink a requested element. As we have singly-linked lists, the
+ * caller also needs to pass in the previous element (or NULL, if it is the
+ * root element).
+ * rgerhards, 2007-11-21
+ */
+static rsRetVal llUnlinkElt(linkedList_t *pThis, llElt_t *pElt, llElt_t *pEltPrev)
+{
+	assert(pElt != NULL);
+
+	if(pEltPrev == NULL) { /* root element? */
+		pThis->pRoot = pElt->pNext;
+	} else { /* regular element */
+		pEltPrev->pNext = pElt->pNext;
+	}
+
+	if(pElt == pThis->pLast)
+		pThis->pLast = pEltPrev;
+
+	return RS_RET_OK;
+}
+
+
+/* unlinks and immediately deletes an element. Previous element must
+ * be given (or zero if the root element is to be deleted).
+ * rgerhards, 2007-11-21
+ */
+static rsRetVal llUnlinkAndDelteElt(linkedList_t *pThis, llElt_t *pElt, llElt_t *pEltPrev)
+{
+	DEFiRet;
+
+	assert(pElt != NULL);
+
+	CHKiRet(llUnlinkElt(pThis, pElt, pEltPrev));
+	CHKiRet(llDestroyElt(pThis, pElt));
+
+finalize_it:
+	RETiRet;
+}
+
+/* find a user element based on the provided key - this is the
+ * internal variant, which also tracks the last element pointer
+ * before the found element. This is necessary to delete elements.
+ * NULL means there is no element in front of it, aka the found elt
+ * is the root elt.
+ * rgerhards, 2007-11-21
+ */
+static rsRetVal llFindElt(linkedList_t *pThis, void *pKey, llElt_t **ppElt, llElt_t **ppEltPrev)
+{
+	DEFiRet;
+	llElt_t *pElt;
+	llElt_t *pEltPrev = NULL;
+	int bFound = 0;
+
+	assert(pThis != NULL);
+	assert(pKey != NULL);
+	assert(ppElt != NULL);
+	assert(ppEltPrev != NULL);
+
+	pElt = pThis->pRoot;
+	while(pElt != NULL && bFound == 0) {
+		if(pThis->cmpOp(pKey, pElt->pKey) == 0)
+			bFound = 1;
+		else {
+			pEltPrev = pElt;
+			pElt = pElt->pNext;
+		}
+	}
+
+	if(bFound == 1) {
+		*ppElt = pElt;
+		*ppEltPrev = pEltPrev;
+	} else
+		iRet = RS_RET_NOT_FOUND;
+
+	RETiRet;
+}
+
+
+/* find a user element based on the provided key
+ */
+rsRetVal llFind(linkedList_t *pThis, void *pKey, void **ppData)
+{
+	DEFiRet;
+	llElt_t *pElt;
+	llElt_t *pEltPrev;
+
+	CHKiRet(llFindElt(pThis, pKey, &pElt, &pEltPrev));
+
+	/* if we reach this point, we have found the element */
+	*ppData = pElt->pData;
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* find a delete an element based on user-provided key. The element is
+ * delete, the caller does not receive anything. If we need to receive
+ * the element before destruction, we may implement an llFindAndUnlink()
+ * at that time.
+ * rgerhards, 2007-11-21
+ */
+rsRetVal llFindAndDelete(linkedList_t *pThis, void *pKey)
+{
+	DEFiRet;
+	llElt_t *pElt;
+	llElt_t *pEltPrev;
+
+	CHKiRet(llFindElt(pThis, pKey, &pElt, &pEltPrev));
+
+	/* if we reach this point, we have found an element */
+	CHKiRet(llUnlinkAndDelteElt(pThis, pElt, pEltPrev));
+
+finalize_it:
+	RETiRet;
+}
+
+
+/* provide the count of linked list elements
+ */
+rsRetVal llGetNumElts(linkedList_t *pThis, int *piCnt)
+{
+	DEFiRet;
+
+	assert(pThis != NULL);
+	assert(piCnt != NULL);
+
+	*piCnt = pThis->iNumElts;
+
+	RETiRet;
+}
+
+
+/* execute a function on all list members. The functions receives a
+ * user-supplied parameter, which may be either a simple value
+ * or a pointer to a structure with more data. If the user-supplied
+ * function does not return RS_RET_OK, this function here terminates.
+ * rgerhards, 2007-08-02
+ * rgerhards, 2007-11-21: added functionality to delete a list element.
+ * If the called user function returns RS_RET_OK_DELETE_LISTENTRY the current element
+ * is deleted.
+ */
+rsRetVal llExecFunc(linkedList_t *pThis, rsRetVal (*pFunc)(void*, void*), void* pParam)
+{
+	DEFiRet;
+	rsRetVal iRetLL;
+	void *pData;
+	linkedListCookie_t llCookie = NULL;
+	linkedListCookie_t llCookiePrev = NULL; /* previous list element (needed for deletion, NULL = at root) */
+
+	assert(pThis != NULL);
+	assert(pFunc != NULL);
+
+	while((iRetLL = llGetNextElt(pThis, &llCookie, (void**)&pData)) == RS_RET_OK) {
+		iRet = pFunc(pData, pParam);
+		if(iRet == RS_RET_OK_DELETE_LISTENTRY) {
+			/* delete element */
+			CHKiRet(llUnlinkAndDelteElt(pThis, llCookie, llCookiePrev));
+			/* we need to revert back, as we have just deleted the current element.
+			 * So the actual current element is the one before it, which happens to be
+			 * stored in llCookiePrev. -- rgerhards, 2007-11-21
+			 */
+			llCookie = llCookiePrev;
+		} else if (iRet != RS_RET_OK) {
+			FINALIZE;
+		}
+		llCookiePrev = llCookie;
+	}
+
+	if(iRetLL != RS_RET_END_OF_LINKEDLIST)
+		iRet = iRetLL;
+
+finalize_it:
+	RETiRet;
+}
+
+/* vim:set ai:
+ */