carto/lib/carto/tree/definition.js

Mapnik Stylesheet Compiler

(function(tree) {
var assert = require('assert'),
    _ = require('lodash'),
    util = require('../util');

// A definition is the combination of a selector and rules, like
// #foo {
//     polygon-opacity:1.0;
// }
//
// The selector can have filters
tree.Definition = function Definition(env, selector, rules) {
    this.elements = selector.elements;
    assert.ok(selector.filters instanceof tree.Filterset);
    this.rules = rules;
    this.ruleIndex = {};
    for (var i = 0; i < this.rules.length; i++) {
        if ('zoom' in this.rules[i]) this.rules[i] = this.rules[i].clone();
        this.rules[i].zoom = selector.zoom;
        this.ruleIndex[this.rules[i].updateID()] = true;
    }
    this.filters = selector.filters;
    this.zoom = selector.zoom;
    this.attachment = selector.attachment || '__default__';
    this.specificity = selector.specificity();
    this.matchCount = 0;
    this.ref = env.ref;

    // special handling for Map selector
    if (_.isArray(this.elements) && this.elements.length > 0 &&
        this.elements[0].value === 'Map') {
        this.matchCount = 1;
    }
};

tree.Definition.prototype.toString = function() {
    var str = this.filters.toString();
    for (var i = 0; i < this.rules.length; i++) {
        str += '\n    ' + this.rules[i];
    }
    return str;
};

tree.Definition.prototype.clone = function(filters) {
    if (filters) assert.ok(filters instanceof tree.Filterset);
    var clone = Object.create(tree.Definition.prototype);
    clone.rules = this.rules.slice();
    clone.ruleIndex = _.clone(this.ruleIndex);
    clone.filters = filters ? filters : this.filters.clone();
    clone.attachment = this.attachment;
    clone.ref = this.ref;
    return clone;
};

tree.Definition.prototype.addRules = function(rules) {
    var added = 0;

    for (var i = 0; i < rules.length; i++) {
        // only add rule if not for whole symbolizer (default)
        // and if unique
        if (this.ref.selectorName(rules[i].name) !== 'default' &&
            !this.ruleIndex[rules[i].id]) {
            this.rules.push(rules[i]);
            this.ruleIndex[rules[i].id] = true;
            added++;
        }
    }

    return added;
};

// Determine whether this selector matches a given id,
// array of classes and zoom range, by determining whether
// all elements it contains match.
tree.Definition.prototype.appliesTo = function(id, classes, zoom) {
    if (typeof zoom === 'undefined' || (this.zoom & zoom) > 0) {
        for (var i = 0, l = this.elements.length; i < l; i++) {
            var elem = this.elements[i];
            if (!(elem.wildcard ||
                (elem.type === 'class' && classes[elem.clean]) ||
                (elem.type === 'id' && id === elem.clean))) return false;
        }
        this.matchCount++;
        return true;
    }
    return false;
};

function symbolizerName(symbolizer) {
    function capitalize(str) { return str[1].toUpperCase(); }
    return symbolizer.charAt(0).toUpperCase() +
           symbolizer.slice(1).replace(/\-./, capitalize) + 'Symbolizer';
}

// Get a simple list of the symbolizers, in order
function symbolizerList(sym_order) {
    return sym_order.sort(function(a, b) { return a[1] - b[1]; })
        .map(function(v) { return v[0]; });
}

tree.Definition.prototype.symbolizersToObject = function(env, symbolizers, zoom) {
    var ruleContent = [],
        filter = this.filters.toObject(env);

    ruleContent = _.concat(ruleContent, zoom.toObject(env));
    if (Object.keys(filter).length) {
        ruleContent.push(filter);
    }

    // Sort symbolizers by the index of their first property definition
    var sym_order = [], indexes = [];
    for (var key in symbolizers) {
        indexes = [];
        for (var prop in symbolizers[key]) {
            indexes.push(symbolizers[key][prop].index);
        }
        var min_idx = Math.min.apply(Math, indexes);
        sym_order.push([key, min_idx]);
    }

    sym_order = symbolizerList(sym_order);
    var sym_count = 0;

    for (var i = 0; i < sym_order.length; i++) {
        var doNotSerialize = false;
        var attributes = symbolizers[sym_order[i]];
        var symbolizer = sym_order[i].split('/').pop();

        // Skip the magical * symbolizer which is used for universal properties
        // which are bubbled up to Style elements intead of Symbolizer elements.
        if (symbolizer === '*') continue;
        sym_count++;

        var fail = env.ref.requiredProperties(symbolizer, attributes);
        if (fail) {
            var rule = attributes[Object.keys(attributes).shift()];
            util.error(env, {
                message: fail,
                index: rule.index,
                filename: rule.filename
            });
        }

        var name = symbolizerName(symbolizer),
            symbolizerObject = {},
            symbolizerAttr = [];

        _.set(symbolizerObject, '_name', name);

        var selfclosing = true, tagcontent;
        // iterate through attributes sorted by cartocss name
        Object.keys(attributes).sort().forEach(function(j) {
            if (symbolizer === 'map') util.error(env, {
                message: 'Map properties are not permitted in other rules',
                index: attributes[j].index,
                filename: attributes[j].filename
            });
            var x = env.ref.selector(attributes[j].name);
            if (x && x.serialization && x.serialization === 'content') {
                selfclosing = false;
                tagcontent = attributes[j].ev(env).toObject(env, true);
            } else if (x && x.serialization && x.serialization === 'tag') {
                selfclosing = false;
                tagcontent = attributes[j].ev(env).toObject(env, true);
            } else {
                var attr = attributes[j].ev(env);
                // if we have a rule for the whole symbolizer (default) with keyword none
                // don't output the rule
                if (env.ref.selectorName(attr.name) === 'default' &&
                    attr.value.value[0].is === 'keyword') {
                    if (attr.value.value[0].value === 'none') {
                        doNotSerialize = true;
                        // still call toObject for validation
                        attr.toObject(env);
                    }
                    else if (attr.value.value[0].value === 'auto') {
                        // still call toObject for validation
                        attr.toObject(env);
                    }
                }

                // only output attributes that don't use the keywords none and auto
                if (!(attr.value.value[0].is === 'keyword' &&
                    (attr.value.value[0].value === 'none' || attr.value.value[0].value === 'auto'))) {
                    symbolizerAttr.push(attr.toObject(env));
                }
                else {
                    if (!_.has(x, 'type')) {
                        symbolizerAttr.push(attr.toObject(env));
                    }
                    else if (x.type === 'string' || x.type === 'uri') {
                        symbolizerAttr.push(attr.toObject(env));
                    }
                }
            }
        });

        if (doNotSerialize) {
            continue;
        }

        if (symbolizerAttr.length) {
            var attrObj = {};

            _.forEach(symbolizerAttr, function (a) {
                _.forOwn(a, function (v, k) {
                    attrObj[k] = v;
                });
            });
            _.set(symbolizerObject, '_attributes', attrObj);
        }
        if (!selfclosing && typeof tagcontent !== 'undefined') {
            _.set(symbolizerObject, '_content', tagcontent);
        }

        if (Object.keys(symbolizerObject).length) {
            ruleContent.push(symbolizerObject);
        }
    }
    if (!sym_count || !ruleContent.length) return {};
    return {
        '_name': 'Rule',
        '_content': ruleContent
    };
};

// Take a zoom range of zooms and 'i', the index of a rule in this.rules,
// and finds all applicable symbolizers
tree.Definition.prototype.collectSymbolizers = function(zooms, i) {
    var symbolizers = {}, child;

    for (var j = i; j < this.rules.length; j++) {
        child = this.rules[j];
        var key = child.instance + '/' + child.symbolizer;
        if (zooms.current & child.zoom &&
           (!(key in symbolizers) ||
           (!(child.name in symbolizers[key])))) {
            zooms.current &= child.zoom;
            if (!(key in symbolizers)) {
                symbolizers[key] = {};
            }
            symbolizers[key][child.name] = child;
        }
    }

    if (Object.keys(symbolizers).length) {
        zooms.rule &= (zooms.available &= ~zooms.current);
        return symbolizers;
    }
};

// The tree.Zoom.toString function ignores the holes in zoom ranges and outputs
// scaledenominators that cover the whole range from the first to last bit set.
// This algorithm can produces zoom ranges that may have holes. However,
// when using the filter-mode="first", more specific zoom filters will always
// end up before broader ranges. The filter-mode will pick those first before
// resorting to the zoom range with the hole and stop processing further rules.
tree.Definition.prototype.toObject = function(env, existing) {
    var filter = this.filters.toString();
    if (!(filter in existing)) existing[filter] = tree.Zoom.all;

    var available = tree.Zoom.all,
        objects = [],
        symbolizers,
        zooms = { available: tree.Zoom.all };

    for (var i = 0; i < this.rules.length && available; i++) {
        zooms.rule = this.rules[i].zoom;
        if (!(existing[filter] & zooms.rule)) continue;

        do {
            zooms.current = zooms.rule & available;
            if (zooms.current) {
                symbolizers = this.collectSymbolizers(zooms, i);
                if (symbolizers) {
                    if (!(existing[filter] & zooms.current)) continue;
                    objects.push(this.symbolizersToObject(env, symbolizers,
                        (new tree.Zoom()).setZoom(existing[filter] & zooms.current)));
                    existing[filter] &= ~zooms.current;
                }
            }
        }
        while (zooms.current);
    }

    if (objects.length == 1) return objects[0];
    return objects;
};

})(require('../tree'));