379 lines
13 KiB
JavaScript
379 lines
13 KiB
JavaScript
var path = require('path'),
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fs = require('fs'),
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External = require('./external'),
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Step = require('step'),
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_ = require('underscore')._,
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sys = require('sys'),
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mess = require('mess');
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require.paths.unshift(path.join(__dirname, '..', 'lib'));
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/**
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* Rendering circuitry for JSON map manifests.
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*
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* This is node-only for the time being.
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*/
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/**
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* Convert a two-element-per-item Array
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* into an object, for the purpose of checking membership
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* and replacing stuff.
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* @param {Array} list a list.
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*/
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var to = function(list) {
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return list && list[0] && _.reduce(list, function(m, r) {
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if (r && r.length > 1) {
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m[r[0]] = r[1];
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}
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return m;
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}, {});
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};
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mess.Renderer = function Renderer(env) {
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var env = {
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data_dir: env.data_dir || '/tmp/',
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local_data_dir: env.local_data_dir || '',
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validation_data: env.validation_data || false
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};
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return {
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/**
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* Keep a copy of passed-in environment variables
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*/
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env: env,
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/**
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* Wrapper for downloading externals: likely removable
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*
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* @param {String} uri the URI of the resource.
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* @param {Function} callback
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*/
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grab: function(uri, callback) {
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new(External)(this.env).process(uri, callback);
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},
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/**
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* Download any file-based remote datsources.
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*
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* Usable as an entry point: does not expect any modification to
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* the map object beyond JSON parsing.
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*
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* @param {Object} m map object.
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* @param {Function} callback
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*/
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localizeExternals: function(m, callback) {
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var that = this;
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Step(
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function() {
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var group = this.group();
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m.Layer.forEach(function(l) {
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if (l.Datasource.file) {
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that.grab(l.Datasource.file, group());
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}
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});
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if (m.Layer.length == 0) group()();
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},
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function(err, results) {
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var result_map = to(results);
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m.Layer = _.map(_.filter(m.Layer,
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function(l) {
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return l.Datasource.file &&
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result_map[l.Datasource.file];
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}),
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function(l) {
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l.Datasource.file = result_map[l.Datasource.file];
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return l;
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}
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);
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callback(err, m);
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}
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);
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},
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/**
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* Download any remote stylesheets
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*
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* @param {Object} m map object.
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* @param {Function} callback
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*/
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localizeStyle: function(m, callback) {
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var that = this;
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Step(
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function() {
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var group = this.group();
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m.Stylesheet.forEach(function(s) {
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if (!s.id) {
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that.grab(s, group());
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}
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});
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group()();
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},
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function(err, results) {
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var result_map = to(results);
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for (s in m.Stylesheet) {
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if (!m.Stylesheet[s].id) {
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m.Stylesheet[s] = result_map[m.Stylesheet[s]];
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}
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}
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callback(err, m);
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}
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);
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},
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/**
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* Compile (already downloaded) styles with mess.js,
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* calling callback with an array of [map object, [stylesheet objects]]
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*
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* Called with the results of localizeStyle or localizeExternals:
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* expects not to handle downloading.
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*
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* @param {Object} m map object.
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* @param {Function} callback
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*/
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style: function(m, callback) {
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var that = this;
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Step(
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function() {
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var group = this.group();
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m.Stylesheet.forEach(function(s) {
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if (s.id) {
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group()(null, [s.id, s.data]);
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} else {
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fs.readFile(s, 'utf-8', function(err, data) {
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group()(err, [s, data]);
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});
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}
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});
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},
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function(e, results) {
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var options = {},
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group = this.group();
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for (var i = 0, l = results.length; i < l; i++) {
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new(mess.Parser)(_.extend(_.extend({
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filename: s
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}, that.env), this.env)).parse(results[i][1],
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function(err, tree) {
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if (err) {
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mess.writeError(err, options);
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throw err;
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} else {
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try {
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group()(err, [
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results[i][0],
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tree.toCSS({ compress: false }),
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tree]);
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return;
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} catch (e) {
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throw e;
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return;
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}
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}
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});
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}
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},
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function(err, results) {
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if (err) {
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callback(err);
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return;
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}
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var result_map = to(results);
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for (s in m.Stylesheet) {
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if (!m.Stylesheet[s].id) {
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m.Stylesheet[s] = result_map[m.Stylesheet[s]];
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} else {
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m.Stylesheet[s] = result_map[m.Stylesheet[s].id];
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}
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}
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callback(err, [m, results]);
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}
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);
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},
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/**
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* Split definitions into sub-lists of definitions
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* containing rules pertaining to only one
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* symbolizer each
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*/
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split_symbolizers: function(definitions) {
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var by_symbolizer = {};
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for (var i = 0; i < definitions.length; i++) {
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definitions[i].symbolizers().forEach(function(sym) {
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if(!by_symbolizer[sym]) {
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by_symbolizer[sym] = [];
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}
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by_symbolizer[sym].push(
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definitions[i].filter_symbolizer(sym));
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});
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}
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return by_symbolizer;
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},
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/**
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* Pick the 'winners' - all elements that select
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* properly. Apply inherited styles from their
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* ancestors to them.
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*/
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process_chain: function(definitions) {
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// definitions are ordered in specificity,
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// high to low
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//
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// basically if 'this level' has
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// a filter, then keep going, otherwise
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// this is the final selector.
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var winners = [];
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var ancestors = [];
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var below_threshold = false;
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while (def = definitions.shift()) {
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if (below_threshold) {
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ancestors.push(def)
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} else if (def.selector.specificity()[2] > 0) {
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winners.push(def);
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} else {
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winners.push(def);
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// nothing below this level will win
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below_threshold = true;
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}
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}
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// iterate in reverse - low to high specificity
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for (var i = ancestors.length - 1; i >= 0; i--) {
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for (var j = 0; j < winners.length; j++) {
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winners[j].inherit_from(ancestors[i]);
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}
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}
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winners = this.resolve_filters(winners);
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return winners;
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},
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resolve_filters: function(definitions) {
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var negated_filters = [];
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for (var i = 0; i < definitions.length; i++) {
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if (definitions[i].selector.filters.length) {
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// array of the negation of this definition's filters
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var negation = definitions[i].selector.filters.map(
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function(f) { return f.negate(); });
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// add in existing negations
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// TODO: run uniq on this.
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definitions[i].selector.filters =
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definitions[i].selector.filters.concat(negated_filters);
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// add this definition's filter's negations to the list
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negated_filters = negated_filters.concat(negation);
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}
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}
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return definitions;
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},
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/**
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* Prepare full XML map output. Called with the results
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* of this.style
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*
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* @param {Array} res array of [map object, stylesheets].
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* @param {Function} callback
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*/
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template: function(err, res, callback) {
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if (err) {
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callback(err);
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return;
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}
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var that = this,
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m = res[0],
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stylesheets = res[1],
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entities = _.template('<?xml version="1.0" ' +
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'encoding="utf-8"?>\n' +
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'<!DOCTYPE Map[\n' +
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'<% for (ref in externals) { %>' +
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' <!ENTITY <%= ref %> SYSTEM "<%= externals[ref] %>">\n' +
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'<% } %>]>\n'),
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// for the Map[] doctype: XML entities to
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// organize code
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entity_list = { externals: [], symbols: [] };
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/**
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* Add styles to a layer object
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*
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* @param {Object} layer the layer object.
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* @param {Array} stylesheets the results of ruleHash().
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* @return Formalized layer definition with .styles = [].
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*/
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var rulesets = _.flatten(stylesheets.map(function(rulesets) {
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return rulesets[2].toMSS();
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}));
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// TODO: must change when background colors are available
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var output = [
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'<?xml version="1.0" '
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+ 'encoding="utf-8"?>\n'
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+ '<!DOCTYPE Map[]>\n'
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+ '<Map background-color="'
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+ "#ffffff"
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// findBackground(stylesheets)
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+ '" srs="+proj=merc +a=6378137 +b=6378137 '
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+ '+lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m '
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+ '+nadgrids=@null +no_defs">\n'];
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m.Layer.forEach(function(l) {
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l.styles = [];
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var classes = (l['class'] || '').split(/\s+/g);
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var matching = rulesets.filter(function(ruleset) {
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return ruleset.selector.matches(l.id, classes);
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});
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// matching is an array of matching selectors,
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// in order from high specificity to low.
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var by_symbolizer = that.split_symbolizers(matching);
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for (sym in by_symbolizer) {
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// Create styles out of chains of one-symbolizer rules,
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// and assign those styles to layers
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var new_style = new(mess.tree.Style)(
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l.id,
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sym,
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that.process_chain(by_symbolizer[sym]));
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l.styles.push(new_style.name());
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output.push(new_style.toXML());
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}
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var nl = new(mess.tree.Layer)(l);
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output.push(nl.toXML());
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});
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output.push('</Map>');
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callback(null, output.join('\n'));
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},
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/**
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* Prepare a JML document (given as a string) into a
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* fully-localized XML file ready for Mapnik2 consumption
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*
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* @param {String} str the JSON file as a string.
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* @param {Function} callback to be called with err, XML representation.
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*/
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render: function(str, callback) {
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var m = JSON.parse(str),
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that = this;
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this.localizeExternals(m, function(err, res) {
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that.localizeStyle(res, function(err, res) {
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that.style(res, function(err, res) {
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that.template(err, res, function(err, res) {
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callback(err, res);
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});
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});
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});
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});
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}
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};
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};
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module.exports = mess;
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