Add a dart library and a dart script for creating version numbers.

tools/testing/dart/version.dart

Index: tools/testing/dart/version.dart
===================================================================
--- tools/testing/dart/version.dart	(revision 0)
+++ tools/testing/dart/version.dart	(revision 0)
@@ -0,0 +1,172 @@
+// Copyright (c) 2012, 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.
+
+/**
+ * This file contains functionality for getting dart version numbers using
+ * our standard version construction method. Systems that does not include this
+ * file should emulate the structure for revision numbers that we have here.
+ *
+ * The version number of a dart build is constructed as follows:
+ *   1. The major, minor, build and patch numbers are extracted from the VERSION
+ *      file in the root directory. We call these MAJOR, MINOR, BUILD and PATCH.
+ *   2. The svn revision number for the current checkout is extracted from the
+ *      source control system that is used in the current checkout. We call this
+ *      REVISION.
+ *   3. If this is _not_ a official build, i.e., this is not build by our
+ *      buildbot infrastructure, we extract the user-name of the logged in
+ *      person from the operating system. We call this USERNAME.
+ *   4. The version number is constructed as follows:
+ *      MAJOR.MINOR.BUILD.PATCH_rREVISION_USERNAME
+ */
+
+library version;
+import "dart:io";
+
+/**
+ * Generates version information for builds.
+ */
+class Version {
+  String _versionFileName;
+  String USERNAME;
+  int REVISION;
+  int MAJOR;
+  int MINOR;
+  int BUILD;
+  int PATCH;
+
+  Version(String this._versionFileName);
+
+  /**
+   * Get the version number for this specific build using the version info
+   * from the VERSION file in the root directory and the revision info
+   * from the source control system of the current checkout.
+   */
+  Future<String> getVersion() {
+    File f = new File(_versionFileName);
+    Completer c = new Completer();
+    f.exists().then((existed) {
+      if (!existed) {
+        c.completeException("No VERSION file");
+        return;
+      }
+      StringInputStream input = new StringInputStream(f.openInputStream());
+      input.onLine = () {
+        var line = input.readLine();
+        if (line == null) {
+          c.completeException(
+              "VERSION input file seems to be in the wrong format");
+          return;
+        }
+        var values = line.split(" ");
+        if (values.length != 2) {
+          c.completeException(
+              "VERSION input file seems to be in the wrong format");
+          return;
+        }
+        var number = 0;
+        try {
+          number = int.parse(values[1]);
+        } catch (e) {
+          c.completeException("Can't parse version numbers, not an int");
+          return;
+        }
+        switch (values[0]) {
+          case "MAJOR":
+            MAJOR = number;
+            break;
+          case "MINOR":
+            MINOR = number;
+            break;
+          case "BUILD":
+            BUILD = number;
+            break;
+          case "PATCH":
+            PATCH = number;
+            break;
+          default:
+            c.completeException("Wrong format in VERSION file, line does not "
+                                "contain one of {MAJOR, MINOR, BUILD, PATCH}");
+            return;
+        }
+      };
+      input.onClosed = () {
+        // Only complete if we did not already complete with a failure.
+        if (!c.future.isComplete) {
+          getRevision().then((revision) {
+            REVISION = revision;
+            getUserName().then((username) {
+              USERNAME = username;
+              if (username != '') username = "_$username";
+              var revisionString = "";
+              if (revision != 0) revisionString = "_r$revision";
+              c.complete("$MAJOR.$MINOR.$BUILD.$PATCH$revisionString$username");
+              return;
+            });
+          });
+        }
+      };
+    });
+    return c.future;
+  }
+
+  Future<int> getRevision() {
+    if (repositoryType == RepositoryType.UNKNOWN) {
+      return new Future.immediate(0);
+    }
+    var isSvn = repositoryType == RepositoryType.SVN;
+    var command = isSvn ? "svn" : "git";
+    var arguments = isSvn ? ["info"] : ["svn", "info"];
+    return Process.run(command, arguments).transform((result) {
+      if (result.exitCode != 0) {
+        return 0;
+      }
+      // If anything goes wrong parsing the revision we simply return 0.
+      try {
+        // Extract the revision. It's located at the 8th line,
+        // 18 characters in.
+        String revisionString = result.stdout.split("\n")[8].substring(18);
+        return int.parse(revisionString);
+      } catch (e) {
+        return 0;
+      }
+    });
+  }
+
+  Future<String> getUserName() {
+    // TODO(ricow): Don't add this on the buildbot.
+    // If we can't get the username simple return "" (e.g. on windows).
+    return Process.run("whoami", []).transform((result) {
+      if (result.exitCode != 0) {
+        return "";
+      }
+      return result.stdout;
+    }).transformException((e) {
+      return "";
+    });
+  }
+
+  RepositoryType get repositoryType {
+    if (new Directory(".svn").existsSync()) return RepositoryType.SVN;
+    if (new Directory(".git").existsSync()) return RepositoryType.GIT;
+    return RepositoryType.UNKNOWN;
+  }
+}
+
+class RepositoryType {
+  static final RepositoryType SVN = const RepositoryType("SVN");
+  static final RepositoryType GIT = const RepositoryType("GIT");
+  static final RepositoryType UNKNOWN = const RepositoryType("UNKNOWN");
+
+  const RepositoryType(String this.name);
+
+  static RepositoryType guessType() {
+    if (new Directory(".svn").existsSync()) return RepositoryType.SVN;
+    if (new Directory(".git").existsSync()) return RepositoryType.GIT;
+    return RepositoryType.UNKNOWN;
+  }
+
+  String toString() => name;
+
+  final String name;
+}