atom/vendor/ace/edit_session/bracket_match.js

/* vim:ts=4:sts=4:sw=4:
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Ajax.org Code Editor (ACE).
 *
 * The Initial Developer of the Original Code is
 * Ajax.org B.V.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *      Fabian Jakobs <fabian AT ajax DOT org>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * decision by deleting the provisions above and replace them with the notice
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 * the provisions above, a recipient may use your version of this file under
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 *
 * ***** END LICENSE BLOCK ***** */

define(function(require, exports, module) {

var TokenIterator = require("../token_iterator").TokenIterator;

function BracketMatch() {

    this.findMatchingBracket = function(position) {
        if (position.column == 0) return null;

        var charBeforeCursor = this.getLine(position.row).charAt(position.column-1);
        if (charBeforeCursor == "") return null;

        var match = charBeforeCursor.match(/([\(\[\{])|([\)\]\}])/);
        if (!match) {
            return null;
        }

        if (match[1]) {
            return this.$findClosingBracket(match[1], position);
        } else {
            return this.$findOpeningBracket(match[2], position);
        }
    };

    this.$brackets = {
        ")": "(",
        "(": ")",
        "]": "[",
        "[": "]",
        "{": "}",
        "}": "{"
    };

    this.$findOpeningBracket = function(bracket, position) {
        var openBracket = this.$brackets[bracket];
        var depth = 1;

        var iterator = new TokenIterator(this, position.row, position.column);
        var token = iterator.getCurrentToken();
        if (!token) return null;
        
        // token.type contains a period-delimited list of token identifiers
        // (e.g.: "constant.numeric" or "paren.lparen").  Create a pattern that
        // matches any token containing the same identifiers or a subset.  In
        // addition, if token.type includes "rparen", then also match "lparen".
        // So if type.token is "paren.rparen", then typeRe will match "lparen.paren".
        var typeRe = new RegExp("(\\.?" +
            token.type.replace(".", "|").replace("rparen", "lparen|rparen") + ")+");
        
        // Start searching in token, just before the character at position.column
        var valueIndex = position.column - iterator.getCurrentTokenColumn() - 2;
        var value = token.value;
        
        while (true) {
        
            while (valueIndex >= 0) {
                var char = value.charAt(valueIndex);
                if (char == openBracket) {
                    depth -= 1;
                    if (depth == 0) {
                        return {row: iterator.getCurrentTokenRow(),
                            column: valueIndex + iterator.getCurrentTokenColumn()};
                    }
                }
                else if (char == bracket) {
                    depth += 1;
                }
                valueIndex -= 1;
            }

            // Scan backward through the document, looking for the next token
            // whose type matches typeRe
            do {
                token = iterator.stepBackward();
            } while (token && !typeRe.test(token.type));

            if (token == null)
                break;
                
            value = token.value;
            valueIndex = value.length - 1;
        }
        
        return null;
    };

    this.$findClosingBracket = function(bracket, position) {
        var closingBracket = this.$brackets[bracket];
        var depth = 1;

        var iterator = new TokenIterator(this, position.row, position.column);
        var token = iterator.getCurrentToken();
        if (!token) return null;

        // token.type contains a period-delimited list of token identifiers
        // (e.g.: "constant.numeric" or "paren.lparen").  Create a pattern that
        // matches any token containing the same identifiers or a subset.  In
        // addition, if token.type includes "lparen", then also match "rparen".
        // So if type.token is "lparen.paren", then typeRe will match "paren.rparen".
        var typeRe = new RegExp("(\\.?" +
            token.type.replace(".", "|").replace("lparen", "lparen|rparen") + ")+");

        // Start searching in token, after the character at position.column
        var valueIndex = position.column - iterator.getCurrentTokenColumn();

        while (true) {

            var value = token.value;
            var valueLength = value.length;
            while (valueIndex < valueLength) {
                var char = value.charAt(valueIndex);
                if (char == closingBracket) {
                    depth -= 1;
                    if (depth == 0) {
                        return {row: iterator.getCurrentTokenRow(),
                            column: valueIndex + iterator.getCurrentTokenColumn()};
                    }
                }
                else if (char == bracket) {
                    depth += 1;
                }
                valueIndex += 1;
            }

            // Scan forward through the document, looking for the next token
            // whose type matches typeRe
            do {
                token = iterator.stepForward();
            } while (token && !typeRe.test(token.type));

            if (token == null)
                break;

            valueIndex = 0;
        }
        
        return null;
    };
}
exports.BracketMatch = BracketMatch;

});