[build] convert build-version script from Python to Node.js

cmake/core.cmake

@@ -6,7 +6,7 @@ endif()
 add_custom_command(
     OUTPUT ${MBGL_GENERATED}/include/mbgl/util/version.hpp
     DEPENDS ${MBGL_VERSION_DEPS}
-    COMMAND ${CMAKE_SOURCE_DIR}/scripts/build-version.py ${MBGL_GENERATED}
+    COMMAND ${NodeJS_EXECUTABLE} ${CMAKE_SOURCE_DIR}/scripts/build-version.js ${MBGL_GENERATED}
     VERBATIM
 )
 

scripts/build-version.js

@@ -0,0 +1,81 @@
+#!/usr/bin/env node
+
+var path = require('path');
+var fs = require('fs');
+var util = require('util');
+var mkdirp = require('mkdirp');
+var execSync = require('child_process').execSync;
+
+const DEFAULT_TAG = [0, 0, 0];
+const DEFAULT_REV = 'unknown';
+
+function is_git_repo() {
+    try {
+        execSync('git rev-parse', { stdio: ['ignore', 'ignore', 'ignore'] });
+        return true;
+    } catch(err) {
+        return false;
+    }
+}
+
+
+function parse_tag(raw_tag) {
+    return raw_tag.replace(/[^0-9.]/g, '').split('.').map(parseFloat).slice(0, 3);
+}
+
+function parse_rev(raw_rev) {
+    return raw_rev.substr(0, 8);
+}
+
+var output_dir = process.argv[2];
+
+if (!output_dir) {
+    console.warn('No output directory given.');
+    console.warn('Usage: %s [output dir]', path.basename(process.argv[1]));
+    process.exit(1);
+}
+
+if (is_git_repo()) {
+    var raw_tag = execSync('git describe --tags --always --abbrev=0').toString().trim();
+    var raw_rev = execSync('git rev-parse HEAD').toString().trim();
+
+    // When they're identical, the "git describe" can't find a tag and reports the rev instead.
+    if (raw_tag == raw_rev) {
+        var tag = DEFAULT_TAG
+        var rev = parse_rev(raw_rev)
+    } else {
+        var tag = parse_tag(raw_tag)
+        var rev = parse_rev(raw_rev)
+    }
+}  else {
+    var tag = DEFAULT_TAG;
+    var rev = DEFAULT_REV;
+}
+
+console.log('Tag: %d.%d.%d', tag[0], tag[1], tag[2]);
+console.log('Rev: %s', rev);
+
+var header = '// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.\n' +
+    '#pragma once\n' +
+    '\n' +
+    '#define MBGL_VERSION 0x' + (tag[0] << 16 | tag[1] << 8 | tag[2]).toString(16) + '\n' +
+    '#define MBGL_VERSION_STRING "' + tag[0] + '.' + tag[1] + '.' + tag[2] + '"\n' +
+    '#define MBGL_VERSION_MAJOR ' + tag[0] + '\n' +
+    '#define MBGL_VERSION_MINOR ' + tag[1] + '\n' +
+    '#define MBGL_VERSION_PATCH ' + tag[2] + '\n' +
+    '#define MBGL_VERSION_REV "' + rev + '"\n' +
+    '\n' +
+    'namespace mbgl {\n' +
+    'namespace version {\n' +
+    '\n' +
+    'extern const int major, minor, patch;\n' +
+    'extern const char *revision;\n' +
+    'extern const char *string;\n' +
+    'extern const unsigned int number;\n' +
+    '\n' +
+    '} // namespace version\n' +
+    '} // namespace mbgl\n';
+
+var header_path = path.join(output_dir, 'include/mbgl/util/version.hpp')
+mkdirp.sync(path.dirname(header_path));
+fs.writeFileSync(header_path, header);