data: automatically create data/*/VERSION.json for latest

Commited files under data/ folder contain metadata, packed and unpacked
data for all released versions. Releases are normally done with `grunt
release` which calls `grunt data` which uses version latest, so a manual
copy of `data/*/latest.json` to the actual latest version was required
(or forgotten).

So change the pipeline to automatically generate the correctly-versioned
files in addition to latest.

Also move version parsing to data-meta, where it belongs.

tasks/data-dedupe.js

@@ -26,15 +26,6 @@ function dedupe(zone) {
 	};
 }
 
-function findVersion (source) {
-	var matches = source.match(/\nRelease (\d{4}[a-z]) /);
-
-	if (matches && matches[1]) {
-		return matches[1];
-	}
-	throw new Error("Could not find version from temp/download/latest/NEWS.");
-}
-
 function addCountries(countries) {
 	var result = [];
 
@@ -55,14 +46,16 @@ module.exports = function (grunt) {
 		var zones = grunt.file.readJSON('temp/collect/' + version + '.json'),
 			meta = grunt.file.readJSON('data/meta/' + version + '.json'),
 			output = {
-				version : version === 'latest' ?
-					findVersion(grunt.file.read('temp/download/latest/NEWS')) : version,
+				version : meta.version,
 				zones : zones.map(dedupe),
 				links : [],
 				countries : addCountries(meta.countries)
 			};
 
 		grunt.file.write('data/unpacked/' + version + '.json', JSON.stringify(output, null, 2));
+		if (version === 'latest') {
+			grunt.file.copy('data/unpacked/' + version + '.json', 'data/unpacked/' + output.version + '.json');
+		}
 
 		grunt.log.ok('Deduped data for ' + version);
 	});

tasks/data-meta.js

@@ -1,5 +1,22 @@
 "use strict";
 
+var path = require('path');
+
+function parseVersion (grunt, version) {
+	var newsPath = path.join('temp/download', version, 'NEWS'),
+		input = grunt.file.read(newsPath),
+		matches = input.match(/\nRelease (\d{4}[a-z]) /);
+
+	if (matches && matches[1]) {
+		if (version !== 'latest' && version !== matches[1]) {
+			throw new Error("Parsed version " + matches[1] +
+				" differs from specified version " + version)
+		}
+		return matches[1];
+	}
+	throw new Error("Could not find version from " + newsPath);
+}
+
 function parseLatLong (input, isLong) {
 	var sign = input[0] === '+' ? 1 : -1,
 		deg = ~~input.substr(1, 2 + isLong) * sign,
@@ -127,12 +144,16 @@ module.exports = function (grunt) {
 		var validCountries = filterCountries(countries);
 
 		var output = {
+			version: parseVersion(grunt, version),
 			countries: validCountries,
 			zones: zones
 		};
 
 		grunt.file.write('data/meta/' + version + '.json', JSON.stringify(output, null, '\t'));
+		if (version === 'latest') {
+			grunt.file.copy('data/meta/latest.json', 'data/meta/' + output.version + '.json');
+		}
 
-		grunt.log.ok('Added metadata for ' + version);
+		grunt.log.ok('Added metadata for ' + version + (version === 'latest' ? ': ' + output.version : ''));
 	});
 };

tasks/data-pack.js

@@ -19,6 +19,9 @@ module.exports = function (grunt) {
 		});
 
 		grunt.file.write('data/packed/' + version + '.json', JSON.stringify(output, null, '\t'));
+		if (version === 'latest') {
+			grunt.file.copy('data/packed/latest.json', 'data/packed/' + unpacked.version + '.json');
+		}
 
 		grunt.log.ok('Packed data for ' + version);
 	});