overleaf/services/web/public/js/ace/edit_session/fold.js

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define(function(require, exports, module) {
"use strict";

var Range = require("../range").Range;
var RangeList = require("../range_list").RangeList;
var oop = require("../lib/oop")
/*
 * Simple fold-data struct.
 **/
var Fold = exports.Fold = function(range, placeholder) {
    this.foldLine = null;
    this.placeholder = placeholder;
    this.range = range;
    this.start = range.start;
    this.end = range.end;

    this.sameRow = range.start.row == range.end.row;
    this.subFolds = this.ranges = [];
};

oop.inherits(Fold, RangeList);

(function() {

    this.toString = function() {
        return '"' + this.placeholder + '" ' + this.range.toString();
    };

    this.setFoldLine = function(foldLine) {
        this.foldLine = foldLine;
        this.subFolds.forEach(function(fold) {
            fold.setFoldLine(foldLine);
        });
    };

    this.clone = function() {
        var range = this.range.clone();
        var fold = new Fold(range, this.placeholder);
        this.subFolds.forEach(function(subFold) {
            fold.subFolds.push(subFold.clone());
        });
        fold.collapseChildren = this.collapseChildren;
        return fold;
    };

    this.addSubFold = function(fold) {
        if (this.range.isEqual(fold))
            return;

        if (!this.range.containsRange(fold))
            throw new Error("A fold can't intersect already existing fold" + fold.range + this.range);

        // transform fold to local coordinates
        consumeRange(fold, this.start);

        var row = fold.start.row, column = fold.start.column;
        for (var i = 0, cmp = -1; i < this.subFolds.length; i++) {
            cmp = this.subFolds[i].range.compare(row, column);
            if (cmp != 1)
                break;
        }
        var afterStart = this.subFolds[i];

        if (cmp == 0)
            return afterStart.addSubFold(fold);

        // cmp == -1
        var row = fold.range.end.row, column = fold.range.end.column;
        for (var j = i, cmp = -1; j < this.subFolds.length; j++) {
            cmp = this.subFolds[j].range.compare(row, column);
            if (cmp != 1)
                break;
        }
        var afterEnd = this.subFolds[j];

        if (cmp == 0)
            throw new Error("A fold can't intersect already existing fold" + fold.range + this.range);

        var consumedFolds = this.subFolds.splice(i, j - i, fold);
        fold.setFoldLine(this.foldLine);

        return fold;
    };
    
    this.restoreRange = function(range) {
        return restoreRange(range, this.start);
    };

}).call(Fold.prototype);

function consumePoint(point, anchor) {
    point.row -= anchor.row;
    if (point.row == 0)
        point.column -= anchor.column;
}
function consumeRange(range, anchor) {
    consumePoint(range.start, anchor);
    consumePoint(range.end, anchor);
}
function restorePoint(point, anchor) {
    if (point.row == 0)
        point.column += anchor.column;
    point.row += anchor.row;
}
function restoreRange(range, anchor) {
    restorePoint(range.start, anchor);
    restorePoint(range.end, anchor);
}

});