org.eclipse.jdt/org.eclipse.jdt.core/3.20.0 : org/eclipse/jdt/core/dom/DefaultCommentMapper.java

DefaultCommentMapper
http://www.eclipse.org/jdt: Java Development Tools Core (Eclipse Foundation)
Eclipse Public License - v 2.0
Copyright (c) 2004, 2011 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
/*******************************************************************************
 * Copyright (c) 2004, 2011 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.jdt.core.dom;

import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.core.compiler.InvalidInputException;
import org.eclipse.jdt.internal.compiler.parser.Scanner;
import org.eclipse.jdt.internal.compiler.parser.TerminalTokens;
import org.eclipse.jdt.internal.compiler.util.Util;

Internal class for associating comments with AST nodes.
Since: 3.0/**
 * Internal class for associating comments with AST nodes.
 *
 * @since 3.0
 */
class DefaultCommentMapper {
	Comment[] comments;
	Scanner scanner;

	// extended nodes storage
	int leadingPtr;
	ASTNode[] leadingNodes;
	long[] leadingIndexes;
	int trailingPtr, lastTrailingPtr;
	ASTNode[] trailingNodes;
	long[] trailingIndexes;
	static final int STORAGE_INCREMENT = 16;

	Params: table – the given table of comments/**
	 * @param table the given table of comments
	 */
	DefaultCommentMapper(Comment[] table) {
		this.comments = table;
	}

	boolean hasSameTable(Comment[] table) {
		return this.comments == table;
	}

	Get comment of the list which includes a given position
Params: position – The position belonging to the looked up comment
Returns: comment which includes the given position or null if none was found/**
	 * Get comment of the list which includes a given position
	 *
	 * @param position The position belonging to the looked up comment
	 * @return comment which includes the given position or null if none was found
	 */
	Comment getComment(int position) {

		if (this.comments == null) {
			return null;
		}
		int size = this.comments.length;
		if (size == 0) {
			return null;
		}
		int index = getCommentIndex(0, position, 0);
		if (index<0) {
			return null;
		}
		return this.comments[index];
	}

	/*
	 * Get the index of comment which contains given position.
	 * If there's no matching comment, then return depends on exact parameter:
	 *		= 0: return -1
	 *		< 0: return index of the comment before the given position
	 *		> 0: return index of the comment after the given position
	 */
	private int getCommentIndex(int start, int position, int exact) {
		if (position == 0) {
			if (this.comments.length > 0 && this.comments[0].getStartPosition() == 0) {
				return 0;
			}
			return -1;
		}
		int bottom = start, top = this.comments.length - 1;
		int i = 0, index = -1;
		Comment comment = null;
		while (bottom <= top) {
			i = bottom + (top - bottom) /2;
			comment = this.comments[i];
			int commentStart = comment.getStartPosition();
			if (position < commentStart) {
				top = i-1;
			} else if (position >=(commentStart+comment.getLength())) {
				bottom = i+1;
			} else {
				index = i;
				break;
			}
		}
		if (index<0 && exact!=0) {
			comment = this.comments[i];
			if (position < comment.getStartPosition()) {
				return exact<0 ? i-1 : i;
			} else {
				return exact<0 ? i : i+1;
			}
		}
		return index;
	}

	Returns the extended start position of the given node. Unlike ASTNode.getStartPosition() and ASTNode.getLength(), the extended source range may include comments and whitespace immediately before or after the normal source range for the node. 
Params: node – the node
See Also: getExtendedLength(ASTNode)
Returns: the 0-based character index, or -1
   if no source position information is recorded for this node
Since: 3.0/**
	 * Returns the extended start position of the given node. Unlike
	 * {@link ASTNode#getStartPosition()} and {@link ASTNode#getLength()},
	 * the extended source range may include comments and whitespace
	 * immediately before or after the normal source range for the node.
	 *
	 * @param node the node
	 * @return the 0-based character index, or <code>-1</code>
	 *    if no source position information is recorded for this node
	 * @see #getExtendedLength(ASTNode)
	 * @since 3.0
	 */
	public int getExtendedStartPosition(ASTNode node) {
		if (this.leadingPtr >= 0) {
			long range = -1;
			for (int i=0; range<0 && i<=this.leadingPtr; i++) {
				if (this.leadingNodes[i] == node) range = this.leadingIndexes[i];
			}
			if (range >= 0) {
				return  this.comments[(int)(range>>32)].getStartPosition() ;
			}
		}
		return node.getStartPosition();
	}

	/*
	 * Search the line number corresponding to a specific position
	 * between the given line range (inclusive)
	 * @param position int
	 * @parem lineRange size-2 int[]
	 * @return int
	 */
	public final int getLineNumber(int position, int[] lineRange) {
		int[] lineEnds = this.scanner.lineEnds;
		int length = lineEnds.length;
		return Util.getLineNumber(position, lineEnds, (lineRange[0] > length ? length : lineRange[0]) -1, (lineRange[1] > length ? length : lineRange[1]) - 1);
	}

	/*
	 * Returns the extended end position of the given node.
	 */
	public int getExtendedEnd(ASTNode node) {
		int end = node.getStartPosition() + node.getLength();
		if (this.trailingPtr >= 0) {
			long range = -1;
			for (int i=0; range<0 && i<=this.trailingPtr; i++) {
				if (this.trailingNodes[i] == node) range = this.trailingIndexes[i];
			}
			if (range >= 0) {
				Comment lastComment = this.comments[(int) range];
				end = lastComment.getStartPosition() + lastComment.getLength();
			}
		}
		return end-1;
	}

	Returns the extended source length of the given node. Unlike ASTNode.getStartPosition() and ASTNode.getLength(), the extended source range may include comments and whitespace immediately before or after the normal source range for the node. 
Params: node – the node
See Also: getExtendedStartPosition(ASTNode)
getExtendedEnd(ASTNode)
Returns: a (possibly 0) length, or 0
   if no source position information is recorded for this node
Since: 3.0/**
	 * Returns the extended source length of the given node. Unlike
	 * {@link ASTNode#getStartPosition()} and {@link ASTNode#getLength()},
	 * the extended source range may include comments and whitespace
	 * immediately before or after the normal source range for the node.
	 *
	 * @param node the node
	 * @return a (possibly 0) length, or <code>0</code>
	 *    if no source position information is recorded for this node
	 * @see #getExtendedStartPosition(ASTNode)
	 * @see #getExtendedEnd(ASTNode)
	 * @since 3.0
	 */
	public int getExtendedLength(ASTNode node) {
		return getExtendedEnd(node) - getExtendedStartPosition(node) + 1;
	}

	Return index of first leading comment of a given node.
Params: node – 
Returns: index of first leading comment or -1 if node has no leading comment/**
	 * Return index of first leading comment of a given node.
	 *
	 * @param node
	 * @return index of first leading comment or -1 if node has no leading comment
	 */
	int firstLeadingCommentIndex(ASTNode node) {
		if (this.leadingPtr >= 0) {
			for (int i=0; i<=this.leadingPtr; i++) {
				if (this.leadingNodes[i] == node) {
					return (int) (this.leadingIndexes[i]>>32);
				}
			}
		}
		return -1;
	}

	Return index of last trailing comment of a given node.
Params: node – 
Returns: index of last trailing comment or -1 if node has no trailing comment/**
	 * Return index of last trailing comment of a given node.
	 *
	 * @param node
	 * @return index of last trailing comment or -1 if node has no trailing comment
	 */
	int lastTrailingCommentIndex(ASTNode node) {
		if (this.trailingPtr >= 0) {
			for (int i=0; i<=this.trailingPtr; i++) {
				if (this.trailingNodes[i] == node) {
					return (int) this.trailingIndexes[i];
				}
			}
		}
		return -1;
	}

	/*
	 * Initialize leading and trailing comments tables in whole nodes hierarchy of a compilation
	 * unit.
	 * Scanner is necessary to scan between nodes and comments and verify if there's
	 * nothing else than white spaces.
	 */
	void initialize(CompilationUnit unit, Scanner sc) {

		// Init array pointers
		this.leadingPtr = -1;
		this.trailingPtr = -1;

		// Init comments
		this.comments = unit.optionalCommentTable;
		if (this.comments == null) {
			return;
		}
		int size = this.comments.length;
		if (size == 0) {
			return;
		}

		// Init scanner and start ranges computing
		this.scanner = sc;
		this.scanner.tokenizeWhiteSpace = true;

		// Start unit visit
		DefaultASTVisitor commentVisitor = new CommentMapperVisitor();
		unit.accept(commentVisitor);

		// Reduce leading arrays if necessary
		int leadingCount = this.leadingPtr + 1;
		if (leadingCount > 0 && leadingCount < this.leadingIndexes.length) {
			System.arraycopy(this.leadingNodes, 0, this.leadingNodes = new ASTNode[leadingCount], 0, leadingCount);
			System.arraycopy(this.leadingIndexes, 0, this.leadingIndexes= new long[leadingCount], 0, leadingCount);
		}

		// Reduce trailing arrays if necessary
		if (this.trailingPtr >= 0) {
			// remove last remaining unresolved nodes
			while (this.trailingIndexes[this.trailingPtr] == -1) {
				this.trailingPtr--;
				if (this.trailingPtr < 0) {
					this.trailingIndexes = null;
					this.trailingNodes = null;
					break;
				}
			}

			// reduce array size
			int trailingCount = this.trailingPtr + 1;
			if (trailingCount > 0 && trailingCount < this.trailingIndexes.length) {
				System.arraycopy(this.trailingNodes, 0, this.trailingNodes = new ASTNode[trailingCount], 0, trailingCount);
				System.arraycopy(this.trailingIndexes, 0, this.trailingIndexes= new long[trailingCount], 0, trailingCount);
			}
		}

		// Release scanner as it's only used during unit visit
		this.scanner = null;
	}

	Search and store node leading comments. Comments are searched in position range
from previous extended position to node start position. If one or several comment are found,
returns first comment start position, otherwise returns node start position.

Starts to search for first comment before node start position and return if none was found...

When first comment is found before node, goes up in comment list until one of
following conditions becomes true:

	comment end is before previous end
	comment start and previous end is on the same line but not on same line of node start
	there's other than white characters between current node and comment
	there's more than 1 line between current node and comment

If some comment have been found, then no token should be on
on the same line before, so remove all comments which do not verify this assumption.

If finally there's leading still comments, then stores indexes of the first and last one
in leading comments table.
/**
	 * Search and store node leading comments. Comments are searched in position range
	 * from previous extended position to node start position. If one or several comment are found,
	 * returns first comment start position, otherwise returns node start position.
	 * <p>
	 * Starts to search for first comment before node start position and return if none was found...
	 *</p><p>
	 * When first comment is found before node, goes up in comment list until one of
	 * following conditions becomes true:
	 * <ol>
	 * 	<li>comment end is before previous end</li>
	 * 	<li>comment start and previous end is on the same line but not on same line of node start</li>
	 * 	<li>there's other than white characters between current node and comment</li>
	 * 	<li>there's more than 1 line between current node and comment</li>
	 * </ol>
	 * If some comment have been found, then no token should be on
	 * on the same line before, so remove all comments which do not verify this assumption.
	 * </p><p>
	 * If finally there's leading still comments, then stores indexes of the first and last one
	 * in leading comments table.
	 */
	int storeLeadingComments(ASTNode node, int previousEnd, int[] parentLineRange) {
		// Init extended position
		int nodeStart = node.getStartPosition();
		int extended = nodeStart;

		// Get line of node start position
		int previousEndLine = getLineNumber(previousEnd, parentLineRange);
		int nodeStartLine = getLineNumber(nodeStart, parentLineRange);

		// Find first comment index
		int idx = getCommentIndex(0, nodeStart, -1);
		if (idx == -1) {
			return nodeStart;
		}

		// Look after potential comments
		int startIdx = -1;
		int endIdx = idx;
		int previousStart = nodeStart;
		while (idx >= 0 && previousStart  >= previousEnd) {
			// Verify for each comment that there's only white spaces between end and start of {following comment|node}
			Comment comment = this.comments[idx];
			int commentStart = comment.getStartPosition();
			int end = commentStart+comment.getLength()-1;
			int commentLine = getLineNumber(commentStart, parentLineRange);
			if (end <= previousEnd || (commentLine == previousEndLine && commentLine != nodeStartLine)) {
				// stop search on condition 1) and 2)
				break;
			} else if ((end+1) < previousStart) { // may be equals => then no scan is necessary
				this.scanner.resetTo(end+1, previousStart);
				try {
					int token = this.scanner.getNextToken();
					if (token != TerminalTokens.TokenNameWHITESPACE || this.scanner.currentPosition != previousStart) {
						// stop search on condition 3)
						// if first comment fails, then there's no extended position in fact
						if (idx == endIdx) {
							return nodeStart;
						}
						break;
					}
				} catch (InvalidInputException e) {
					// Should not happen, but return no extended position...
					return nodeStart;
				}
				// verify that there's no more than one line between node/comments
				char[] gap = this.scanner.getCurrentIdentifierSource();
				int nbrLine = 0;
				int pos = -1;
				while ((pos=CharOperation.indexOf('\n', gap,pos+1)) >= 0) {
					nbrLine++;
				}
				if (nbrLine > 1) {
					// stop search on condition 4)
					break;
				}
			}
			// Store previous infos
			previousStart = commentStart;
			startIdx = idx--;
		}
		if (startIdx != -1) {
			// Verify that there's no token on the same line before first leading comment
			int commentStart = this.comments[startIdx].getStartPosition();
			if (previousEnd < commentStart && previousEndLine != nodeStartLine) {
				int lastTokenEnd = previousEnd;
				this.scanner.resetTo(previousEnd, commentStart);
				try {
					while (this.scanner.currentPosition < commentStart) {
						if (this.scanner.getNextToken() != TerminalTokens.TokenNameWHITESPACE) {
							lastTokenEnd =  this.scanner.getCurrentTokenEndPosition();
						}
					}
				} catch (InvalidInputException e) {
					// do nothing
				}
				int lastTokenLine = getLineNumber(lastTokenEnd, parentLineRange);
				int length = this.comments.length;
				while (startIdx<length && lastTokenLine == getLineNumber(this.comments[startIdx].getStartPosition(), parentLineRange) && nodeStartLine != lastTokenLine) {
					startIdx++;
				}
			}
			// Store leading comments indexes
			if (startIdx <= endIdx) {
				if (++this.leadingPtr == 0) {
					this.leadingNodes = new ASTNode[STORAGE_INCREMENT];
					this.leadingIndexes = new long[STORAGE_INCREMENT];
				} else if (this.leadingPtr == this.leadingNodes.length) {
					int newLength = (this.leadingPtr*3/2)+STORAGE_INCREMENT;
					System.arraycopy(this.leadingNodes, 0, this.leadingNodes = new ASTNode[newLength], 0, this.leadingPtr);
					System.arraycopy(this.leadingIndexes, 0, this.leadingIndexes = new long[newLength], 0, this.leadingPtr);
				}
				this.leadingNodes[this.leadingPtr] = node;
				this.leadingIndexes[this.leadingPtr] = (((long)startIdx)<<32) + endIdx;
				extended = this.comments[endIdx].getStartPosition();
			}
		}
		return extended;
	}

	Search and store node trailing comments. Comments are searched in position range
from node end position to specified next start. If one or several comment are found,
returns last comment end position, otherwise returns node end position.

Starts to search for first comment after node end position and return if none was found...

When first comment is found after node, goes down in comment list until one of
following conditions becomes true:

	comment start is after next start
	there's other than white characters between current node and comment
	there's more than 1 line between current node and comment

If at least potential comments have been found, then all of them has to be separated
from following node. So, remove all comments which do not verify this assumption.
Note that this verification is not applicable on last node.

If finally there's still trailing comments, then stores indexes of the first and last one
in trailing comments table.
/**
	 * Search and store node trailing comments. Comments are searched in position range
	 * from node end position to specified next start. If one or several comment are found,
	 * returns last comment end position, otherwise returns node end position.
	 * <p>
	 * Starts to search for first comment after node end position and return if none was found...
	 *</p><p>
	 * When first comment is found after node, goes down in comment list until one of
	 * following conditions becomes true:
	 * <ol>
	 * 	<li>comment start is after next start</li>
	 * 	<li>there's other than white characters between current node and comment</li>
	 * 	<li>there's more than 1 line between current node and comment</li>
	 *</ol>
	 * If at least potential comments have been found, then all of them has to be separated
	 * from following node. So, remove all comments which do not verify this assumption.
	 * Note that this verification is not applicable on last node.
	 * </p><p>
	 * If finally there's still trailing comments, then stores indexes of the first and last one
	 * in trailing comments table.
	 */
	int storeTrailingComments(ASTNode node, int nextStart,  boolean lastChild, int[] parentLineRange) {

		// Init extended position
		int nodeEnd = node.getStartPosition()+node.getLength()-1;
		if (nodeEnd == nextStart) {
			// special case for last child of its parent
			if (++this.trailingPtr == 0) {
				this.trailingNodes = new ASTNode[STORAGE_INCREMENT];
				this.trailingIndexes = new long[STORAGE_INCREMENT];
				this.lastTrailingPtr = -1;
			} else if (this.trailingPtr == this.trailingNodes.length) {
				int newLength = (this.trailingPtr*3/2)+STORAGE_INCREMENT;
				System.arraycopy(this.trailingNodes, 0, this.trailingNodes = new ASTNode[newLength], 0, this.trailingPtr);
				System.arraycopy(this.trailingIndexes, 0, this.trailingIndexes = new long[newLength], 0, this.trailingPtr);
			}
			this.trailingNodes[this.trailingPtr] = node;
			this.trailingIndexes[this.trailingPtr] = -1;
			return nodeEnd;
		}
		int extended = nodeEnd;

		// Get line number
		int nodeEndLine = getLineNumber(nodeEnd, parentLineRange);

		// Find comments range index
		int idx = getCommentIndex(0, nodeEnd, 1);
		if (idx == -1) {
			return nodeEnd;
		}

		// Look after potential comments
		int startIdx = idx;
		int endIdx = -1;
		int length = this.comments.length;
		int commentStart = extended+1;
		int previousEnd = nodeEnd+1;
		int sameLineIdx = -1;
		while (idx<length && commentStart < nextStart) {
			// get comment and leave if next starting position has been reached
			Comment comment = this.comments[idx];
			commentStart = comment.getStartPosition();
			// verify that there's nothing else than white spaces between node/comments
			if (commentStart >= nextStart) {
				// stop search on condition 1)
				break;
			} else if (previousEnd < commentStart) {
				this.scanner.resetTo(previousEnd, commentStart);
				try {
					int token = this.scanner.getNextToken();
					if (token != TerminalTokens.TokenNameWHITESPACE || this.scanner.currentPosition != commentStart) {
						// stop search on condition 2)
						// if first index fails, then there's no extended position in fact...
						if (idx == startIdx) {
							return nodeEnd;
						}
						// otherwise we get the last index of trailing comment => break
						break;
					}
				} catch (InvalidInputException e) {
					// Should not happen, but return no extended position...
					return nodeEnd;
				}
				// verify that there's no more than one line between node/comments
				char[] gap = this.scanner.getCurrentIdentifierSource();
				int nbrLine = 0;
				int pos = -1;
				while ((pos=CharOperation.indexOf('\n', gap,pos+1)) >= 0) {
					nbrLine++;
				}
				if (nbrLine > 1) {
					// stop search on condition 3)
					break;
				}
			}
			// Store index if we're on the same line than node end
			int commentLine = getLineNumber(commentStart, parentLineRange);
			if (commentLine == nodeEndLine) {
				sameLineIdx = idx;
			}
			// Store previous infos
			previousEnd = commentStart+comment.getLength();
			endIdx = idx++;
		}
		if (endIdx != -1) {
			// Verify that following node start is separated
			if (!lastChild) {
				int nextLine = getLineNumber(nextStart, parentLineRange);
				int previousLine = getLineNumber(previousEnd, parentLineRange);
				if((nextLine - previousLine) <= 1) {
					if (sameLineIdx == -1) return nodeEnd;
					endIdx = sameLineIdx;
				}
			}
			// Store trailing comments indexes
			if (++this.trailingPtr == 0) {
				this.trailingNodes = new ASTNode[STORAGE_INCREMENT];
				this.trailingIndexes = new long[STORAGE_INCREMENT];
				this.lastTrailingPtr = -1;
			} else if (this.trailingPtr == this.trailingNodes.length) {
				int newLength = (this.trailingPtr*3/2)+STORAGE_INCREMENT;
				System.arraycopy(this.trailingNodes, 0, this.trailingNodes = new ASTNode[newLength], 0, this.trailingPtr);
				System.arraycopy(this.trailingIndexes, 0, this.trailingIndexes = new long[newLength], 0, this.trailingPtr);
			}
			this.trailingNodes[this.trailingPtr] = node;
			long nodeRange = (((long)startIdx)<<32) + endIdx;
			this.trailingIndexes[this.trailingPtr] = nodeRange;
			// Compute new extended end
			extended = this.comments[endIdx].getStartPosition()+this.comments[endIdx].getLength()-1;
			// Look for children unresolved extended end
			ASTNode previousNode = node;
			int ptr = this.trailingPtr - 1; // children extended end were stored before
			while (ptr >= 0) {
				long range = this.trailingIndexes[ptr];
				if (range != -1) break; // there's no more unresolved nodes
				ASTNode unresolved = this.trailingNodes[ptr];
				if (previousNode != unresolved.getParent()) break; // we're no longer in node ancestor hierarchy
				this.trailingIndexes[ptr] = nodeRange;
				previousNode = unresolved;
				ptr--; // get previous node
			}
			// Remove remaining unresolved nodes
			if (ptr > this.lastTrailingPtr) {
				int offset = ptr - this.lastTrailingPtr;
				for (int i=ptr+1; i<=this.trailingPtr; i++) {
					this.trailingNodes[i-offset] = this.trailingNodes[i];
					this.trailingIndexes[i-offset] = this.trailingIndexes[i];
				}
				this.trailingPtr -= offset;
			}
			this.lastTrailingPtr = this.trailingPtr;
		}
		return extended;
	}

	class CommentMapperVisitor extends DefaultASTVisitor {

		ASTNode topSiblingParent = null;
		ASTNode[] siblings = new ASTNode[10];
		int[][] parentLineRange = new int[10][];
		int siblingPtr = -1;

		@Override
		protected boolean visitNode(ASTNode node) {

			// Get default previous end
			ASTNode parent = node.getParent();
			int previousEnd = parent.getStartPosition();

			// Look for sibling node
 			ASTNode sibling = parent == this.topSiblingParent ? (ASTNode) this.siblings[this.siblingPtr] : null;
			if (sibling != null) {
				// Found one previous sibling, so compute its trailing comments using current node start position
				try {
					previousEnd = storeTrailingComments(sibling, node.getStartPosition(), false, this.parentLineRange[this.siblingPtr]);
				} catch (Exception ex) {
					// Give up extended ranges at this level if unexpected exception happens...
				}
			}

			// Stop visit for malformed node (see bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=84049)
			if ((node.typeAndFlags & ASTNode.MALFORMED) != 0) {
				return false;
			}

			// Compute leading comments for current node
			int[] previousLineRange = this.siblingPtr > -1 ? this.parentLineRange[this.siblingPtr] : new int[] {1, DefaultCommentMapper.this.scanner.linePtr+1};
			try {
				storeLeadingComments(node, previousEnd, previousLineRange);
			} catch (Exception ex) {
				// Give up extended ranges at this level if unexpected exception happens...
			}

			// Store current node as waiting sibling for its parent
			if (this.topSiblingParent != parent) {
				if (this.siblings.length == ++this.siblingPtr) {
					System.arraycopy(this.siblings, 0, this.siblings = new ASTNode[this.siblingPtr*2], 0, this.siblingPtr);
					System.arraycopy(this.parentLineRange, 0, this.parentLineRange = new int[this.siblingPtr*2][], 0, this.siblingPtr);
				}
				if (this.topSiblingParent == null) {
					// node is a CompilationUnit
					this.parentLineRange[this.siblingPtr] = previousLineRange;
				} else {
					int parentStart = parent.getStartPosition();
					int firstLine = getLineNumber(parentStart, previousLineRange);
					int lastLine = getLineNumber(parentStart + parent.getLength() - 1, previousLineRange);
					if (this.parentLineRange[this.siblingPtr] == null) {
						this.parentLineRange[this.siblingPtr] = new int[] {firstLine, lastLine};
					} else {
						int[] lineRange = this.parentLineRange[this.siblingPtr];
						lineRange[0] = firstLine;
						lineRange[1] = lastLine;
					}
				}
				this.topSiblingParent = parent;
			}
			this.siblings[this.siblingPtr] = node;

			// We're always ok to visit sub-levels
			return true;
		}

		@Override
		protected void endVisitNode(ASTNode node) {

			// Look if a child node is waiting for trailing comments computing
			ASTNode sibling = this.topSiblingParent == node ? (ASTNode) this.siblings[this.siblingPtr] : null;
			if (sibling != null) {
				try {
					storeTrailingComments(sibling, node.getStartPosition()+node.getLength()-1, true, this.parentLineRange[this.siblingPtr]);
				} catch (Exception ex) {
					// Give up extended ranges at this level if unexpected exception happens...
				}
			}
			// Remove sibling if needed
			if (this.topSiblingParent != null /*not a CompilationUnit*/
					&& this.topSiblingParent == node) {
				this.siblingPtr--;
				this.topSiblingParent = node.getParent();
			}
		}

		@Override
		public boolean visit (Modifier modifier) {
			// we don't want to map comment to the modifier
			return false;
		}
		@Override
		public boolean visit ( CompilationUnit node) {
			// do nothing special, just go down in sub-levels
			return true;
		}
	}
}
Params:	position – The position belonging to the looked up comment
Returns:	comment which includes the given position or null if none was found
Params:	node – the node
See Also:	getExtendedLength(ASTNode)
Returns:	the 0-based character index, or `-1` if no source position information is recorded for this node
Since:	3.0
Params:	node –
Returns:	index of first leading comment or -1 if node has no leading comment
/

org.eclipse.jdt/ org.eclipse.jdt.core/ 3.20.0/ org/eclipse/jdt/core/dom/DefaultCommentMapper.java
