org.eclipse.jface.text.TreeLineTracker Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2005, 2015 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.text;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.text.AbstractLineTracker.DelimiterInfo;
/**
* Abstract implementation of ILineTracker. It lets the definition of line
* delimiters to subclasses. Assuming that '\n' is the only line delimiter, this abstract
* implementation defines the following line scheme:
*
* - "" -> [0,0]
*
- "a" -> [0,1]
*
- "\n" -> [0,1], [1,0]
*
- "a\n" -> [0,2], [2,0]
*
- "a\nb" -> [0,2], [2,1]
*
- "a\nbc\n" -> [0,2], [2,3], [5,0]
*
*
* This class must be subclassed.
*
*
* Performance: The query operations perform in O(log n) where n
* is the number of lines in the document. The modification operations roughly perform in O(l *
* log n) where n is the number of lines in the document and l is the
* sum of the number of removed, added or modified lines.
*
*
* @since 3.2
*/
abstract class TreeLineTracker implements ILineTracker {
/*
* Differential Balanced Binary Tree
*
* Assumption: lines cannot overlap => there exists a total ordering of the lines by their offset,
* which is the same as the ordering by line number
*
* Base idea: store lines in a binary search tree
* - the key is the line number / line offset
* -> lookup_line is O(log n)
* -> lookup_offset is O(log n)
* - a change in a line somewhere will change any succeeding line numbers / line offsets
* -> replace is O(n)
*
* Differential tree: instead of storing the key (line number, line offset) directly, every node
* stores the difference between its key and its parent's key
* - the sort key is still the line number / line offset, but it remains "virtual"
* - inserting a node (a line) really increases the virtual key of all succeeding nodes (lines), but this
* fact will not be realized in the key information encoded in the nodes.
* -> any change only affects the nodes in the node's parent chain, although more bookkeeping
* has to be done when changing a node or balancing the tree
* -> replace is O(log n)
* -> line offsets and line numbers have to be computed when walking the tree from the root /
* from a node
* -> still O(log n)
*
* The balancing algorithm chosen does not depend on the differential tree property. An AVL tree
* implementation has been chosen for simplicity.
*/
/*
* Turns assertions on/off. Don't make this a a debug option for performance reasons - this way
* the compiler can optimize the asserts away.
*/
private static final boolean ASSERT= false;
/**
* The empty delimiter of the last line. The last line and only the last line must have this
* zero-length delimiter.
*/
private static final String NO_DELIM= ""; //$NON-NLS-1$
/**
* A node represents one line. Its character and line offsets are 0-based and relative to the
* subtree covered by the node. All nodes under the left subtree represent lines before, all
* nodes under the right subtree lines after the current node.
*/
private static final class Node {
Node(int length, String delimiter) {
this.length= length;
this.delimiter= delimiter;
}
/**
* The line index in this node's line tree, or equivalently, the number of lines in the left
* subtree.
*/
int line;
/**
* The line offset in this node's line tree, or equivalently, the number of characters in
* the left subtree.
*/
int offset;
/** The number of characters in this line. */
int length;
/** The line delimiter of this line, needed to answer the delimiter query. */
String delimiter;
/** The parent node, null if this is the root node. */
Node parent;
/** The left subtree, possibly null. */
Node left;
/** The right subtree, possibly null. */
Node right;
/** The balance factor. */
byte balance;
@Override
public final String toString() {
String bal;
switch (balance) {
case 0:
bal= "="; //$NON-NLS-1$
break;
case 1:
bal= "+"; //$NON-NLS-1$
break;
case 2:
bal= "++"; //$NON-NLS-1$
break;
case -1:
bal= "-"; //$NON-NLS-1$
break;
case -2:
bal= "--"; //$NON-NLS-1$
break;
default:
bal= Byte.toString(balance);
}
return "[" + offset + "+" + pureLength() + "+" + delimiter.length() + "|" + line + "|" + bal + "]"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ //$NON-NLS-6$
}
/**
* Returns the pure (without the line delimiter) length of this line.
*
* @return the pure line length
*/
int pureLength() {
return length - delimiter.length();
}
}
/**
* The root node of the tree, never null.
*/
private Node fRoot= new Node(0, NO_DELIM);
/**
* Creates a new line tracker.
*/
protected TreeLineTracker() {
}
/**
* Package visible constructor for creating a tree tracker from a list tracker.
*
* @param tracker the list line tracker
*/
TreeLineTracker(ListLineTracker tracker) {
final List lines= tracker.getLines();
final int n= lines.size();
if (n == 0)
return;
Line line= lines.get(0);
String delim= line.delimiter;
if (delim == null)
delim= NO_DELIM;
int length= line.length;
fRoot= new Node(length, delim);
Node node= fRoot;
for (int i= 1; i < n; i++) {
line= lines.get(i);
delim= line.delimiter;
if (delim == null)
delim= NO_DELIM;
length= line.length;
node= insertAfter(node, length, delim);
}
if (node.delimiter != NO_DELIM)
insertAfter(node, 0, NO_DELIM);
if (ASSERT) checkTree();
}
/**
* Returns the node (line) including a certain offset. If the offset is between two
* lines, the line starting at offset is returned.
*
* This means that for offsets smaller than the length, the following holds:
*
*
* line.offset <= offset < line.offset + offset.length.
*
*
* If offset is the document length, then this is true:
*
*
* offset= line.offset + line.length.
*
*
* @param offset a document offset
* @return the line starting at or containing offset
* @throws BadLocationException if the offset is invalid
*/
private Node nodeByOffset(final int offset) throws BadLocationException {
/*
* Works for any binary search tree.
*/
int remaining= offset;
Node node= fRoot;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(offset));
if (remaining < node.offset) {
node= node.left;
} else {
remaining -= node.offset;
if (remaining < node.length
|| remaining == node.length && node.right == null) { // last line
break;
}
remaining -= node.length;
node= node.right;
}
}
return node;
}
/**
* Returns the line number for the given offset. If the offset is between two lines, the line
* starting at offset is returned. The last line is returned if
* offset is equal to the document length.
*
* @param offset a document offset
* @return the line number starting at or containing offset
* @throws BadLocationException if the offset is invalid
*/
private int lineByOffset(final int offset) throws BadLocationException {
/*
* Works for any binary search tree.
*/
int remaining= offset;
Node node= fRoot;
int line= 0;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(offset));
if (remaining < node.offset) {
node= node.left;
} else {
remaining -= node.offset;
line+= node.line;
if (remaining < node.length || remaining == node.length && node.right == null) // last line
return line;
remaining -= node.length;
line ++;
node= node.right;
}
}
}
/**
* Returns the node (line) with the given line number. Note that the last line is always
* incomplete, i.e. has the {@link #NO_DELIM} delimiter.
*
* @param line a line number
* @return the line with the given line number
* @throws BadLocationException if the line is invalid
*/
private Node nodeByLine(final int line) throws BadLocationException {
/*
* Works for any binary search tree.
*/
int remaining= line;
Node node= fRoot;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(line));
if (remaining == node.line)
break;
if (remaining < node.line) {
node= node.left;
} else {
remaining -= node.line + 1;
node= node.right;
}
}
return node;
}
/**
* Returns the offset for the given line number. Note that the
* last line is always incomplete, i.e. has the {@link #NO_DELIM} delimiter.
*
* @param line a line number
* @return the line offset with the given line number
* @throws BadLocationException if the line is invalid
*/
private int offsetByLine(final int line) throws BadLocationException {
/*
* Works for any binary search tree.
*/
int remaining= line;
int offset= 0;
Node node= fRoot;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(line));
if (remaining == node.line)
return offset + node.offset;
if (remaining < node.line) {
node= node.left;
} else {
remaining -= node.line + 1;
offset += node.offset + node.length;
node= node.right;
}
}
}
/**
* Left rotation - the given node is rotated down, its right child is rotated up, taking the
* previous structural position of node.
*
* @param node the node to rotate around
*/
private void rotateLeft(Node node) {
if (ASSERT) Assert.isNotNull(node);
Node child= node.right;
if (ASSERT) Assert.isNotNull(child);
boolean leftChild= node.parent == null || node == node.parent.left;
// restructure
setChild(node.parent, child, leftChild);
setChild(node, child.left, false);
setChild(child, node, true);
// update relative info
// child becomes the new parent, its line and offset counts increase as the former parent
// moves under child's left subtree
child.line += node.line + 1;
child.offset += node.offset + node.length;
}
/**
* Right rotation - the given node is rotated down, its left child is rotated up, taking the
* previous structural position of node.
*
* @param node the node to rotate around
*/
private void rotateRight(Node node) {
if (ASSERT) Assert.isNotNull(node);
Node child= node.left;
if (ASSERT) Assert.isNotNull(child);
boolean leftChild= node.parent == null || node == node.parent.left;
setChild(node.parent, child, leftChild);
setChild(node, child.right, true);
setChild(child, node, false);
// update relative info
// node loses its left subtree, except for what it keeps in its new subtree
// this is exactly the amount in child
node.line -= child.line + 1;
node.offset -= child.offset + child.length;
}
/**
* Helper method for moving a child, ensuring that parent pointers are set correctly.
*
* @param parent the new parent of child, null to replace the
* root node
* @param child the new child of parent, may be null
* @param isLeftChild true if child shall become
* parent's left child, false if it shall become
* parent's right child
*/
private void setChild(Node parent, Node child, boolean isLeftChild) {
if (parent == null) {
if (child == null)
fRoot= new Node(0, NO_DELIM);
else
fRoot= child;
} else {
if (isLeftChild)
parent.left= child;
else
parent.right= child;
}
if (child != null)
child.parent= parent;
}
/**
* A left rotation around parent, whose structural position is replaced by
* node.
*
* @param node the node moving up and left
* @param parent the node moving left and down
*/
private void singleLeftRotation(Node node, Node parent) {
rotateLeft(parent);
node.balance= 0;
parent.balance= 0;
}
/**
* A right rotation around parent, whose structural position is replaced by
* node.
*
* @param node the node moving up and right
* @param parent the node moving right and down
*/
private void singleRightRotation(Node node, Node parent) {
rotateRight(parent);
node.balance= 0;
parent.balance= 0;
}
/**
* A double left rotation, first rotating right around node, then left around
* parent.
*
* @param node the node that will be rotated right
* @param parent the node moving left and down
*/
private void rightLeftRotation(Node node, Node parent) {
Node child= node.left;
rotateRight(node);
rotateLeft(parent);
if (child.balance == 1) {
node.balance= 0;
parent.balance= -1;
child.balance= 0;
} else if (child.balance == 0) {
node.balance= 0;
parent.balance= 0;
} else if (child.balance == -1) {
node.balance= 1;
parent.balance= 0;
child.balance= 0;
}
}
/**
* A double right rotation, first rotating left around node, then right around
* parent.
*
* @param node the node that will be rotated left
* @param parent the node moving right and down
*/
private void leftRightRotation(Node node, Node parent) {
Node child= node.right;
rotateLeft(node);
rotateRight(parent);
if (child.balance == -1) {
node.balance= 0;
parent.balance= 1;
child.balance= 0;
} else if (child.balance == 0) {
node.balance= 0;
parent.balance= 0;
} else if (child.balance == 1) {
node.balance= -1;
parent.balance= 0;
child.balance= 0;
}
}
/**
* Inserts a line with the given length and delimiter after node.
*
* @param node the predecessor of the inserted node
* @param length the line length of the inserted node
* @param delimiter the delimiter of the inserted node
* @return the inserted node
*/
private Node insertAfter(Node node, int length, String delimiter) {
/*
* An insertion really shifts the key of all succeeding nodes. Hence we insert the added node
* between node and the successor of node. The added node becomes either the right child
* of the predecessor node, or the left child of the successor node.
*/
Node added= new Node(length, delimiter);
if (node.right == null)
setChild(node, added, false);
else
setChild(successorDown(node.right), added, true);
// parent chain update
updateParentChain(added, length, 1);
updateParentBalanceAfterInsertion(added);
return added;
}
/**
* Updates the balance information in the parent chain of node until it reaches the root or
* finds a node whose balance violates the AVL constraint, which is the re-balanced.
*
* @param node the child of the first node that needs balance updating
*/
private void updateParentBalanceAfterInsertion(Node node) {
Node parent= node.parent;
while (parent != null) {
if (node == parent.left)
parent.balance--;
else
parent.balance++;
switch (parent.balance) {
case 1:
case -1:
node= parent;
parent= node.parent;
continue;
case -2:
rebalanceAfterInsertionLeft(node);
break;
case 2:
rebalanceAfterInsertionRight(node);
break;
case 0:
break;
default:
if (ASSERT)
Assert.isTrue(false);
}
return;
}
}
/**
* Re-balances a node whose parent has a double positive balance.
*
* @param node the node to re-balance
*/
private void rebalanceAfterInsertionRight(Node node) {
Node parent= node.parent;
if (node.balance == 1) {
singleLeftRotation(node, parent);
} else if (node.balance == -1) {
rightLeftRotation(node, parent);
} else if (ASSERT) {
Assert.isTrue(false);
}
}
/**
* Re-balances a node whose parent has a double negative balance.
*
* @param node the node to re-balance
*/
private void rebalanceAfterInsertionLeft(Node node) {
Node parent= node.parent;
if (node.balance == -1) {
singleRightRotation(node, parent);
} else if (node.balance == 1) {
leftRightRotation(node, parent);
} else if (ASSERT) {
Assert.isTrue(false);
}
}
@Override
public final void replace(int offset, int length, String text) throws BadLocationException {
if (ASSERT) checkTree();
// Inlined nodeByOffset as we need both node and offset
int remaining= offset;
Node first= fRoot;
final int firstNodeOffset;
while (true) {
if (first == null)
throw new BadLocationException(Integer.toString(offset));
if (remaining < first.offset) {
first= first.left;
} else {
remaining -= first.offset;
if (remaining < first.length
|| remaining == first.length && first.right == null) { // last line
firstNodeOffset= offset - remaining;
break;
}
remaining -= first.length;
first= first.right;
}
}
// Inline nodeByOffset end
if (ASSERT) Assert.isTrue(first != null);
Node last;
if (offset + length < firstNodeOffset + first.length)
last= first;
else
last= nodeByOffset(offset + length);
if (ASSERT) Assert.isTrue(last != null);
int firstLineDelta= firstNodeOffset + first.length - offset;
if (first == last)
replaceInternal(first, text, length, firstLineDelta);
else
replaceFromTo(first, last, text, length, firstLineDelta);
if (ASSERT) checkTree();
}
/**
* Replace happening inside a single line.
*
* @param node the affected node
* @param text the added text
* @param length the replace length, < firstLineDelta
* @param firstLineDelta the number of characters from the replacement offset to the end of
* node > length
*/
private void replaceInternal(Node node, String text, int length, int firstLineDelta) {
// 1) modification on a single line
DelimiterInfo info= text == null ? null : nextDelimiterInfo(text, 0);
if (info == null || info.delimiter == null || text == null) {
// a) trivial case: insert into a single node, no line mangling
int added= text == null ? 0 : text.length();
updateLength(node, added - length);
} else {
// b) more lines to add between two chunks of the first node
// remember what we split off the first line
int remainder= firstLineDelta - length;
String remDelim= node.delimiter;
// join the first line with the first added
int consumed= info.delimiterIndex + info.delimiterLength;
int delta= consumed - firstLineDelta;
updateLength(node, delta);
node.delimiter= info.delimiter;
// Inline addlines start
info= nextDelimiterInfo(text, consumed);
while (info != null) {
int lineLen= info.delimiterIndex - consumed + info.delimiterLength;
node= insertAfter(node, lineLen, info.delimiter);
consumed += lineLen;
info= nextDelimiterInfo(text, consumed);
}
// Inline addlines end
// add remaining chunk merged with last (incomplete) additional line
insertAfter(node, remainder + text.length() - consumed, remDelim);
}
}
/**
* Replace spanning from one node to another.
*
* @param node the first affected node
* @param last the last affected node
* @param text the added text
* @param length the replace length, >= firstLineDelta
* @param firstLineDelta the number of characters removed from the replacement offset to the end
* of node, <= length
*/
private void replaceFromTo(Node node, Node last, String text, int length, int firstLineDelta) {
// 2) modification covers several lines
// delete intermediate nodes
// TODO could be further optimized: replace intermediate lines with intermediate added lines
// to reduce re-balancing
Node successor= successor(node);
while (successor != last) {
length -= successor.length;
Node toDelete= successor;
successor= successor(successor);
updateLength(toDelete, -toDelete.length);
}
DelimiterInfo info= text == null ? null : nextDelimiterInfo(text, 0);
if (info == null || info.delimiter == null || text == null) {
int added= text == null ? 0 : text.length();
// join the two lines if there are no lines added
join(node, last, added - length);
} else {
// join the first line with the first added
int consumed= info.delimiterIndex + info.delimiterLength;
updateLength(node, consumed - firstLineDelta);
node.delimiter= info.delimiter;
length -= firstLineDelta;
// Inline addLines start
info= nextDelimiterInfo(text, consumed);
while (info != null) {
int lineLen= info.delimiterIndex - consumed + info.delimiterLength;
node= insertAfter(node, lineLen, info.delimiter);
consumed += lineLen;
info= nextDelimiterInfo(text, consumed);
}
// Inline addLines end
updateLength(last, text.length() - consumed - length);
}
}
/**
* Joins two consecutive node lines, additionally adjusting the resulting length of the combined
* line by delta. The first node gets deleted.
*
* @param one the first node to join
* @param two the second node to join
* @param delta the delta to apply to the remaining single node
*/
private void join(Node one, Node two, int delta) {
int oneLength= one.length;
updateLength(one, -oneLength);
updateLength(two, oneLength + delta);
}
/**
* Adjusts the length of a node by delta, also adjusting the parent chain of
* node. If the node's length becomes zero and is not the last (incomplete)
* node, it is deleted after the update.
*
* @param node the node to adjust
* @param delta the character delta to add to the node's length
*/
private void updateLength(Node node, int delta) {
if (ASSERT) Assert.isTrue(node.length + delta >= 0);
// update the node itself
node.length += delta;
// check deletion
final int lineDelta;
boolean delete= node.length == 0 && node.delimiter != NO_DELIM;
if (delete)
lineDelta= -1;
else
lineDelta= 0;
// update parent chain
if (delta != 0 || lineDelta != 0)
updateParentChain(node, delta, lineDelta);
if (delete)
delete(node);
}
/**
* Updates the differential indices following the parent chain. All nodes from
* from.parent to the root are updated.
*
* @param node the child of the first node to update
* @param deltaLength the character delta
* @param deltaLines the line delta
*/
private void updateParentChain(Node node, int deltaLength, int deltaLines) {
updateParentChain(node, null, deltaLength, deltaLines);
}
/**
* Updates the differential indices following the parent chain. All nodes from
* from.parent to to (exclusive) are updated.
*
* @param from the child of the first node to update
* @param to the first node not to update
* @param deltaLength the character delta
* @param deltaLines the line delta
*/
private void updateParentChain(Node from, Node to, int deltaLength, int deltaLines) {
Node parent= from.parent;
while (parent != to) {
// only update node if update comes from left subtree
if (from == parent.left) {
parent.offset += deltaLength;
parent.line += deltaLines;
}
from= parent;
parent= from.parent;
}
}
/**
* Deletes a node from the tree, re-balancing it if necessary. The differential indices in the
* node's parent chain have to be updated in advance to calling this method. Generally, don't
* call delete directly, but call update_length(node, -node.length) to
* properly remove a node.
*
* @param node the node to delete.
*/
private void delete(Node node) {
if (ASSERT) Assert.isTrue(node != null);
if (ASSERT) Assert.isTrue(node.length == 0);
Node parent= node.parent;
Node toUpdate; // the parent of the node that lost a child
boolean lostLeftChild;
boolean isLeftChild= parent == null || node == parent.left;
if (node.left == null || node.right == null) {
// 1) node has one child at max - replace parent's pointer with the only child
// also handles the trivial case of no children
Node replacement= node.left == null ? node.right : node.left;
setChild(parent, replacement, isLeftChild);
toUpdate= parent;
lostLeftChild= isLeftChild;
// no updates to do - subtrees stay as they are
} else if (node.right.left == null) {
// 2a) node's right child has no left child - replace node with right child, giving node's
// left subtree to the right child
Node replacement= node.right;
setChild(parent, replacement, isLeftChild);
setChild(replacement, node.left, true);
replacement.line= node.line;
replacement.offset= node.offset;
replacement.balance= node.balance;
toUpdate= replacement;
lostLeftChild= false;
// } else if (node.left.right == null) {
// // 2b) symmetric case
// Node replacement= node.left;
// set_child(parent, replacement, isLeftChild);
// set_child(replacement, node.right, false);
// replacement.balance= node.balance;
// toUpdate= replacement;
// lostLeftChild= true;
} else {
// 3) hard case - replace node with its successor
Node successor= successor(node);
// successor exists (otherwise node would not have right child, case 1)
if (ASSERT) Assert.isNotNull(successor);
// successor has no left child (a left child would be the real successor of node)
if (ASSERT) Assert.isTrue(successor.left == null);
if (ASSERT) Assert.isTrue(successor.line == 0);
// successor is the left child of its parent (otherwise parent would be smaller and
// hence the real successor)
if (ASSERT) Assert.isTrue(successor == successor.parent.left);
// successor is not a child of node (would have been covered by 2a)
if (ASSERT) Assert.isTrue(successor.parent != node);
toUpdate= successor.parent;
lostLeftChild= true;
// update relative indices
updateParentChain(successor, node, -successor.length, -1);
// delete successor from its current place - like 1)
setChild(toUpdate, successor.right, true);
// move node's subtrees to its successor
setChild(successor, node.right, false);
setChild(successor, node.left, true);
// replace node by successor in its parent
setChild(parent, successor, isLeftChild);
// update the successor
successor.line= node.line;
successor.offset= node.offset;
successor.balance= node.balance;
}
updateParentBalanceAfterDeletion(toUpdate, lostLeftChild);
}
/**
* Updates the balance information in the parent chain of node.
*
* @param node the first node that needs balance updating
* @param wasLeftChild true if the deletion happened on node's
* left subtree, false if it occurred on node's right
* subtree
*/
private void updateParentBalanceAfterDeletion(Node node, boolean wasLeftChild) {
while (node != null) {
if (wasLeftChild)
node.balance++;
else
node.balance--;
Node parent= node.parent;
if (parent != null)
wasLeftChild= node == parent.left;
switch (node.balance) {
case 1:
case -1:
return; // done, no tree change
case -2:
if (rebalanceAfterDeletionRight(node.left))
return;
break; // propagate up
case 2:
if (rebalanceAfterDeletionLeft(node.right))
return;
break; // propagate up
case 0:
break; // propagate up
default:
if (ASSERT)
Assert.isTrue(false);
}
node= parent;
}
}
/**
* Re-balances a node whose parent has a double positive balance.
*
* @param node the node to re-balance
* @return true if the re-balancement leaves the height at
* node.parent constant, false if the height changed
*/
private boolean rebalanceAfterDeletionLeft(Node node) {
Node parent= node.parent;
if (node.balance == 1) {
singleLeftRotation(node, parent);
return false;
} else if (node.balance == -1) {
rightLeftRotation(node, parent);
return false;
} else if (node.balance == 0) {
rotateLeft(parent);
node.balance= -1;
parent.balance= 1;
return true;
} else {
if (ASSERT) Assert.isTrue(false);
return true;
}
}
/**
* Re-balances a node whose parent has a double negative balance.
*
* @param node the node to re-balance
* @return true if the re-balancement leaves the height at
* node.parent constant, false if the height changed
*/
private boolean rebalanceAfterDeletionRight(Node node) {
Node parent= node.parent;
if (node.balance == -1) {
singleRightRotation(node, parent);
return false;
} else if (node.balance == 1) {
leftRightRotation(node, parent);
return false;
} else if (node.balance == 0) {
rotateRight(parent);
node.balance= 1;
parent.balance= -1;
return true;
} else {
if (ASSERT) Assert.isTrue(false);
return true;
}
}
/**
* Returns the successor of a node, null if node is the last node.
*
* @param node a node
* @return the successor of node, null if there is none
*/
private Node successor(Node node) {
if (node.right != null)
return successorDown(node.right);
return successorUp(node);
}
/**
* Searches the successor of node in its parent chain.
*
* @param node a node
* @return the first node in node's parent chain that is reached from its left
* subtree, null if there is none
*/
private Node successorUp(final Node node) {
Node child= node;
Node parent= child.parent;
while (parent != null) {
if (child == parent.left)
return parent;
child= parent;
parent= child.parent;
}
if (ASSERT) Assert.isTrue(node.delimiter == NO_DELIM);
return null;
}
/**
* Searches the left-most node in a given subtree.
*
* @param node a node
* @return the left-most node in the given subtree
*/
private Node successorDown(Node node) {
Node child= node.left;
while (child != null) {
node= child;
child= node.left;
}
return node;
}
/* miscellaneous */
/**
* Returns the information about the first delimiter found in the given
* text starting at the given offset.
*
* @param text the text to be searched
* @param offset the offset in the given text
* @return the information of the first found delimiter or null
*/
protected abstract DelimiterInfo nextDelimiterInfo(String text, int offset);
@Override
public final String getLineDelimiter(int line) throws BadLocationException {
Node node= nodeByLine(line);
return node.delimiter == NO_DELIM ? null : node.delimiter;
}
@Override
public final int computeNumberOfLines(String text) {
int count= 0;
int start= 0;
DelimiterInfo delimiterInfo= nextDelimiterInfo(text, start);
while (delimiterInfo != null && delimiterInfo.delimiterIndex > -1) {
++count;
start= delimiterInfo.delimiterIndex + delimiterInfo.delimiterLength;
delimiterInfo= nextDelimiterInfo(text, start);
}
return count;
}
@Override
public final int getNumberOfLines() {
// TODO track separately?
Node node= fRoot;
int lines= 0;
while (node != null) {
lines += node.line + 1;
node= node.right;
}
return lines;
}
@Override
public final int getNumberOfLines(int offset, int length) throws BadLocationException {
if (length == 0)
return 1;
int startLine= lineByOffset(offset);
int endLine= lineByOffset(offset + length);
return endLine - startLine + 1;
}
@Override
public final int getLineOffset(int line) throws BadLocationException {
return offsetByLine(line);
}
@Override
public final int getLineLength(int line) throws BadLocationException {
Node node= nodeByLine(line);
return node.length;
}
@Override
public final int getLineNumberOfOffset(int offset) throws BadLocationException {
return lineByOffset(offset);
}
@Override
public final IRegion getLineInformationOfOffset(final int offset) throws BadLocationException {
// Inline nodeByOffset start as we need both node and offset
int remaining= offset;
Node node= fRoot;
final int lineOffset;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(offset));
if (remaining < node.offset) {
node= node.left;
} else {
remaining -= node.offset;
if (remaining < node.length
|| remaining == node.length && node.right == null) { // last line
lineOffset= offset - remaining;
break;
}
remaining -= node.length;
node= node.right;
}
}
// Inline nodeByOffset end
return new Region(lineOffset, node.pureLength());
}
@Override
public final IRegion getLineInformation(int line) throws BadLocationException {
try {
// Inline nodeByLine start
int remaining= line;
int offset= 0;
Node node= fRoot;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(line));
if (remaining == node.line) {
offset += node.offset;
break;
}
if (remaining < node.line) {
node= node.left;
} else {
remaining -= node.line + 1;
offset += node.offset + node.length;
node= node.right;
}
}
// Inline nodeByLine end
return new Region(offset, node.pureLength());
} catch (BadLocationException x) {
/*
* FIXME: this really strange behavior is mandated by the previous line tracker
* implementation and included here for compatibility. See
* LineTrackerTest3#testFunnyLastLineCompatibility().
*/
if (line > 0 && line == getNumberOfLines()) {
line= line - 1;
// Inline nodeByLine start
int remaining= line;
int offset= 0;
Node node= fRoot;
while (true) {
if (node == null)
throw new BadLocationException(Integer.toString(line));
if (remaining == node.line) {
offset+= node.offset;
break;
}
if (remaining < node.line) {
node= node.left;
} else {
remaining -= node.line + 1;
offset += node.offset + node.length;
node= node.right;
}
}
Node last= node;
// Inline nodeByLine end
if (last.length > 0)
return new Region(offset + last.length, 0);
}
throw x;
}
}
@Override
public final void set(String text) {
fRoot= new Node(0, NO_DELIM);
try {
replace(0, 0, text);
} catch (BadLocationException x) {
throw new InternalError();
}
}
@Override
public String toString() {
int depth= computeDepth(fRoot);
int WIDTH= 30;
int leaves= (int) Math.pow(2, depth - 1);
int width= WIDTH * leaves;
String empty= "."; //$NON-NLS-1$
List roots= new LinkedList<>();
roots.add(fRoot);
StringBuilder buf= new StringBuilder((width + 1) * depth); // see Bug 137688
int indents= leaves;
char[] space= new char[leaves * WIDTH / 2];
Arrays.fill(space, ' ');
for(int d= 0; d < depth; d++) {
// compute indent
indents /= 2;
int spaces= Math.max(0, indents * WIDTH - WIDTH / 2);
// print nodes
for (ListIterator it= roots.listIterator(); it.hasNext();) {
// pad before
buf.append(space, 0, spaces);
Node node= it.next();
String box;
// replace the node with its children
if (node == null) {
it.add(null);
box= empty;
} else {
it.set(node.left);
it.add(node.right);
box= node.toString();
}
// draw the node, pad to WIDTH
int pad_left= (WIDTH - box.length() + 1) / 2;
int pad_right= WIDTH - box.length() - pad_left;
buf.append(space, 0, pad_left);
buf.append(box);
buf.append(space, 0, pad_right);
// pad after
buf.append(space, 0, spaces);
}
buf.append('\n');
}
return buf.toString();
}
/**
* Recursively computes the depth of the tree. Only used by {@link #toString()}.
*
* @param root the subtree to compute the depth of, may be null
* @return the depth of the given tree, 0 if it is null
*/
private byte computeDepth(Node root) {
if (root == null)
return 0;
return (byte) (Math.max(computeDepth(root.left), computeDepth(root.right)) + 1);
}
/**
* Debug-only method that checks the tree structure and the differential offsets.
*/
private void checkTree() {
checkTreeStructure(fRoot);
try {
checkTreeOffsets(nodeByOffset(0), new int[] {0, 0}, null);
} catch (BadLocationException x) {
throw new AssertionError();
}
}
/**
* Debug-only method that validates the tree structure below node. I.e. it
* checks whether all parent/child pointers are consistent and whether the AVL balance
* information is correct.
*
* @param node the node to validate
* @return the depth of the tree under node
*/
private byte checkTreeStructure(Node node) {
if (node == null)
return 0;
byte leftDepth= checkTreeStructure(node.left);
byte rightDepth= checkTreeStructure(node.right);
Assert.isTrue(node.balance == rightDepth - leftDepth);
Assert.isTrue(node.left == null || node.left.parent == node);
Assert.isTrue(node.right == null || node.right.parent == node);
return (byte) (Math.max(rightDepth, leftDepth) + 1);
}
/**
* Debug-only method that checks the differential offsets of the tree, starting at
* node and continuing until last.
*
* @param node the first Node to check, may be null
* @param offLen an array of length 2, with offLen[0] the expected offset of
* node and offLen[1] the expected line of
* node
* @param last the last Node to check, may be null
* @return an int[] of length 2, with the first element being the character
* length of node's subtree, and the second element the number of lines
* in node's subtree
*/
private int[] checkTreeOffsets(Node node, int[] offLen, Node last) {
if (node == last)
return offLen;
Assert.isTrue(node.offset == offLen[0]);
Assert.isTrue(node.line == offLen[1]);
if (node.right != null) {
int[] result= checkTreeOffsets(successorDown(node.right), new int[2], node);
offLen[0] += result[0];
offLen[1] += result[1];
}
offLen[0] += node.length;
offLen[1]++;
return checkTreeOffsets(node.parent, offLen, last);
}
}