michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "txList.h"
michael@0: 
michael@0:   //----------------------------/
michael@0:  //- Implementation of txList -/
michael@0: //----------------------------/
michael@0: 
michael@0: /**
michael@0:  * Default constructor for a txList;
michael@0: **/
michael@0: 
michael@0: txList::txList() {
michael@0:    firstItem  = 0;
michael@0:    lastItem   = 0;
michael@0:    itemCount  = 0;
michael@0: } //-- txList;
michael@0: 
michael@0: /**
michael@0:  * txList destructor, cleans up ListItems, but will not delete the Object
michael@0:  * references
michael@0: */
michael@0: txList::~txList() {
michael@0:     clear();
michael@0: } //-- ~txList
michael@0: 
michael@0: nsresult txList::add(void* objPtr)
michael@0: {
michael@0:     return insertBefore(objPtr, 0);
michael@0: } //-- add
michael@0: 
michael@0: /**
michael@0:  * Returns the number of items in this txList
michael@0: **/
michael@0: int32_t List::getLength() {
michael@0:    return itemCount;
michael@0: } //-- getLength
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * Inserts the given Object pointer as the item just after refItem.
michael@0:  * If refItem is a null pointer the Object will be inserted at the
michael@0:  * beginning of the txList (ie, insert after nothing).
michael@0:  * This method assumes refItem is a member of this list, and since this
michael@0:  * is a private method, I feel that's a valid assumption
michael@0: **/
michael@0: nsresult txList::insertAfter(void* objPtr, ListItem* refItem)
michael@0: {
michael@0:     //-- if refItem == null insert at front
michael@0:     if (!refItem)
michael@0:         return insertBefore(objPtr, firstItem);
michael@0:     return insertBefore(objPtr, refItem->nextItem);
michael@0: } //-- insertAfter
michael@0: 
michael@0: /**
michael@0:  * Inserts the given Object pointer as the item just before refItem.
michael@0:  * If refItem is a null pointer the Object will be inserted at the
michael@0:  * end of the txList (ie, insert before nothing).
michael@0:  * This method assumes refItem is a member of this list, and since this
michael@0:  * is a private method, I feel that's a valid assumption
michael@0: **/
michael@0: nsresult txList::insertBefore(void* objPtr, ListItem* refItem)
michael@0: {
michael@0:     ListItem* item = new ListItem;
michael@0:     NS_ENSURE_TRUE(item, NS_ERROR_OUT_OF_MEMORY);
michael@0: 
michael@0:     item->objPtr = objPtr;
michael@0:     item->nextItem = 0;
michael@0:     item->prevItem = 0;
michael@0: 
michael@0:     //-- if refItem == null insert at end
michael@0:     if (!refItem) {
michael@0:         //-- add to back of list
michael@0:         if (lastItem) {
michael@0:             lastItem->nextItem = item;
michael@0:             item->prevItem = lastItem;
michael@0:         }
michael@0:         lastItem = item;
michael@0:         if (!firstItem)
michael@0:             firstItem = item;
michael@0:     }
michael@0:     else {
michael@0:         //-- insert before given item
michael@0:         item->nextItem = refItem;
michael@0:         item->prevItem = refItem->prevItem;
michael@0:         refItem->prevItem = item;
michael@0: 
michael@0:         if (item->prevItem)
michael@0:             item->prevItem->nextItem = item;
michael@0:         else
michael@0:             firstItem = item;
michael@0:     }
michael@0: 
michael@0:     // increase the item count
michael@0:     ++itemCount;
michael@0:     
michael@0:     return NS_OK;
michael@0: } //-- insertBefore
michael@0: 
michael@0: txList::ListItem* txList::remove(ListItem* item) {
michael@0: 
michael@0:     if (!item)
michael@0:         return item;
michael@0: 
michael@0:     //-- adjust the previous item's next pointer
michael@0:     if (item->prevItem) {
michael@0:         item->prevItem->nextItem = item->nextItem;
michael@0:     }
michael@0:     //-- adjust the next item's previous pointer
michael@0:     if (item->nextItem) {
michael@0:         item->nextItem->prevItem = item->prevItem;
michael@0:     }
michael@0: 
michael@0:     //-- adjust first and last items
michael@0:     if (item == firstItem)
michael@0:         firstItem = item->nextItem;
michael@0:     if (item == lastItem)
michael@0:         lastItem = item->prevItem;
michael@0: 
michael@0:     //-- decrease Item count
michael@0:     --itemCount;
michael@0:     return item;
michael@0: } //-- remove
michael@0: 
michael@0: void txList::clear()
michael@0: {
michael@0:     ListItem* item = firstItem;
michael@0:     while (item) {
michael@0:         ListItem* tItem = item;
michael@0:         item = item->nextItem;
michael@0:         delete tItem;
michael@0:     }
michael@0:     firstItem  = 0;
michael@0:     lastItem   = 0;
michael@0:     itemCount  = 0;
michael@0: }
michael@0: 
michael@0:   //------------------------------------/
michael@0:  //- Implementation of txListIterator -/
michael@0: //------------------------------------/
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * Creates a new txListIterator for the given txList
michael@0:  * @param list, the txList to create an Iterator for
michael@0: **/
michael@0: txListIterator::txListIterator(txList* list) {
michael@0:    this->list   = list;
michael@0:    currentItem  = 0;
michael@0:    atEndOfList  = false;
michael@0: } //-- txListIterator
michael@0: 
michael@0: /**
michael@0:  * Adds the Object pointer to the txList pointed to by this txListIterator.
michael@0:  * The Object pointer is inserted as the next item in the txList
michael@0:  * based on the current position within the txList
michael@0:  * @param objPtr the Object pointer to add to the list
michael@0: **/
michael@0: nsresult txListIterator::addAfter(void* objPtr)
michael@0: {
michael@0:     if (currentItem || !atEndOfList)
michael@0:         return list->insertAfter(objPtr, currentItem);
michael@0:     return list->insertBefore(objPtr, 0);
michael@0: 
michael@0: } //-- addAfter
michael@0: 
michael@0: /**
michael@0:  * Adds the Object pointer to the txList pointed to by this txListIterator.
michael@0:  * The Object pointer is inserted as the previous item in the txList
michael@0:  * based on the current position within the txList
michael@0:  * @param objPtr the Object pointer to add to the list
michael@0: **/
michael@0: nsresult txListIterator::addBefore(void* objPtr)
michael@0: {
michael@0:     if (currentItem || atEndOfList)
michael@0:         return list->insertBefore(objPtr, currentItem);
michael@0:     return list->insertAfter(objPtr, 0);
michael@0: 
michael@0: } //-- addBefore
michael@0: 
michael@0: /**
michael@0:  * Returns true if a successful call to the next() method can be made
michael@0:  * @return true if a successful call to the next() method can be made,
michael@0:  * otherwise false
michael@0: **/
michael@0: bool txListIterator::hasNext() {
michael@0:     bool hasNext = false;
michael@0:     if (currentItem)
michael@0:         hasNext = (currentItem->nextItem != 0);
michael@0:     else if (!atEndOfList)
michael@0:         hasNext = (list->firstItem != 0);
michael@0: 
michael@0:     return hasNext;
michael@0: } //-- hasNext
michael@0: 
michael@0: /**
michael@0:  * Returns the next Object pointer in the list
michael@0: **/
michael@0: void* txListIterator::next() {
michael@0: 
michael@0:     void* obj = 0;
michael@0:     if (currentItem)
michael@0:         currentItem = currentItem->nextItem;
michael@0:     else if (!atEndOfList)
michael@0:         currentItem = list->firstItem;
michael@0: 
michael@0:     if (currentItem)
michael@0:         obj = currentItem->objPtr;
michael@0:     else
michael@0:         atEndOfList = true;
michael@0: 
michael@0:     return obj;
michael@0: } //-- next
michael@0: 
michael@0: /**
michael@0:  * Returns the previous Object in the list
michael@0: **/
michael@0: void* txListIterator::previous() {
michael@0: 
michael@0:     void* obj = 0;
michael@0: 
michael@0:     if (currentItem)
michael@0:         currentItem = currentItem->prevItem;
michael@0:     else if (atEndOfList)
michael@0:         currentItem = list->lastItem;
michael@0:     
michael@0:     if (currentItem)
michael@0:         obj = currentItem->objPtr;
michael@0: 
michael@0:     atEndOfList = false;
michael@0: 
michael@0:     return obj;
michael@0: } //-- previous
michael@0: 
michael@0: /**
michael@0:  * Returns the current Object
michael@0: **/
michael@0: void* txListIterator::current() {
michael@0: 
michael@0:     if (currentItem)
michael@0:         return currentItem->objPtr;
michael@0: 
michael@0:     return 0;
michael@0: } //-- current
michael@0: 
michael@0: /**
michael@0:  * Removes the Object last returned by the next() or previous() methods;
michael@0:  * @return the removed Object pointer
michael@0: **/
michael@0: void* txListIterator::remove() {
michael@0: 
michael@0:     void* obj = 0;
michael@0:     if (currentItem) {
michael@0:         obj = currentItem->objPtr;
michael@0:         txList::ListItem* item = currentItem;
michael@0:         previous(); //-- make previous item the current item
michael@0:         list->remove(item);
michael@0:         delete item;
michael@0:     }
michael@0:     return obj;
michael@0: } //-- remove
michael@0: 
michael@0: /**
michael@0:  * Resets the current location within the txList to the beginning of the txList
michael@0: **/
michael@0: void txListIterator::reset() {
michael@0:    atEndOfList = false;
michael@0:    currentItem = 0;
michael@0: } //-- reset
michael@0: 
michael@0: /**
michael@0:  * Move the iterator to right after the last element
michael@0: **/
michael@0: void txListIterator::resetToEnd() {
michael@0:    atEndOfList = true;
michael@0:    currentItem = 0;
michael@0: } //-- moveToEnd