Reland "Add --version option to dart2js and add version information (if available) to generated cod…

sdk/lib/_internal/compiler/implementation/dart2js.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.cmdline;
 
 import 'dart:async';
 import 'dart:collection' show Queue, LinkedHashMap;
 import 'dart:io';
 import 'dart:utf';
@@ skipping 68 matching lines @@
 
 void compile(List<String> argv) {
   bool isWindows = (Platform.operatingSystem == 'windows');
   Uri libraryRoot = currentDirectory;
   Uri out = currentDirectory.resolve('out.js');
   Uri sourceMapOut = currentDirectory.resolve('out.js.map');
   Uri packageRoot = null;
   List<String> options = new List<String>();
   bool explicitOut = false;
   bool wantHelp = false;
+  bool wantVersion = false;
   String outputLanguage = 'JavaScript';
   bool stripArgumentSet = false;
   bool analyzeOnly = false;
   SourceFileProvider inputProvider = new SourceFileProvider();
   FormattingDiagnosticHandler diagnosticHandler =
       new FormattingDiagnosticHandler(inputProvider);
 
   passThrough(String argument) => options.add(argument);
 
   if (BUILD_ID != null) {
@@ skipping 91 matching lines @@
 
   List<String> arguments = <String>[];
   List<OptionHandler> handlers = <OptionHandler>[
     new OptionHandler('-[chv?]+', handleShortOptions),
     new OptionHandler('--throw-on-error',
                       (_) => diagnosticHandler.throwOnError = true),
     new OptionHandler('--suppress-warnings',
                       (_) => diagnosticHandler.showWarnings = false),
     new OptionHandler('--output-type=dart|--output-type=js', setOutputType),
     new OptionHandler('--verbose', setVerbose),
+    new OptionHandler('--version', (_) => wantVersion = true),
     new OptionHandler('--library-root=.+', setLibraryRoot),
     new OptionHandler('--out=.+|-o.+', setOutput),
     new OptionHandler('--allow-mock-compilation', passThrough),
     new OptionHandler('--minify', passThrough),
     new OptionHandler('--force-strip=.*', setStrip),
     // TODO(ahe): Remove the --no-colors option.
     new OptionHandler('--disable-diagnostic-colors',
                       (_) => diagnosticHandler.enableColors = false),
     new OptionHandler('--enable-diagnostic-colors',
                       (_) => diagnosticHandler.enableColors = true),
@@ skipping 18 matching lines @@
     // The following two options must come last.
     new OptionHandler('-.*', (String argument) {
       helpAndFail('Error: Unknown option "$argument".');
     }),
     new OptionHandler('.*', (String argument) {
       arguments.add(nativeToUriPath(argument));
     })
   ];
 
   parseCommandLine(handlers, argv);
-  if (wantHelp) helpAndExit(diagnosticHandler.verbose);
+  if (wantHelp || wantVersion) {
+    helpAndExit(wantHelp, wantVersion, diagnosticHandler.verbose);
+  }
 
   if (outputLanguage != OUTPUT_LANGUAGE_DART && stripArgumentSet) {
     helpAndFail('Error: --force-strip may only be used with '
         '--output-type=dart');
   }
   if (arguments.isEmpty) {
     helpAndFail('Error: No Dart file specified.');
   }
   if (arguments.length > 1) {
     var extra = arguments.sublist(1);
@@ skipping 157 matching lines @@
 
   -c, --enable-checked-mode, --checked
     Insert runtime type checks and enable assertions (checked mode).
 
   -h, /h, /?, --help
     Display this message (add -v for information about all options).
 
   -v, --verbose
     Display verbose information.
 
+  --version
+    Display version information.
+
   -p<path>, --package-root=<path>
     Where to find packages, that is, "package:..." imports.
 
   --analyze-all
     Analyze all code.  Without this option, the compiler only analyzes
     code that is reachable from [main].  This option is useful for
     finding errors in libraries, but using it can result in bigger and
     slower output.
 
   --analyze-only
@@ skipping 54 matching lines @@
 
   --categories=<categories>
     A comma separated list of allowed library categories.  The default
     is "Client".  Possible categories can be seen by providing an
     unsupported category, for example, --categories=help.  To enable
     all categories, use --categories=all.
 
 '''.trim());
 }
 
-void helpAndExit(bool verbose) {
-  if (verbose) {
-    verboseHelp();
-  } else {
-    help();
+void helpAndExit(bool wantHelp, bool wantVersion, bool verbose) {
+  if (wantVersion) {
+    var version = (BUILD_ID == null)
+        ? '<non-SDK build>'
+        : BUILD_ID;
+    print('Dart-to-JavaScript compiler (dart2js) version: $version');
+  }
+  if (wantHelp) {
+    if (verbose) {
+      verboseHelp();
+    } else {
+      help();
+    }
   }
   exit(0);
 }
 
 void helpAndFail(String message) {
   help();
   print('');
   fail(message);
 }
 
@@ skipping 10 matching lines @@
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }
 
 void main() {
   mainWithErrorHandler(new Options());
 }