code review 4172056: gobuilder: add -package flag to build external packages

misc/dashboard/builder/hg.go

+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package main
 
 import (
         "fmt"
         "os"
+        "regexp"
         "strconv"
         "strings"
 )
 
 type Commit struct {
         num    int    // mercurial revision number
         node   string // mercurial hash
         parent string // hash of commit's parent
         user   string // author's Name <email>
         date   string // date of commit
@@ skipping 34 matching lines @@
                 "--encoding", "utf-8",
                 "--rev", rev,
                 "--limit", "1",
                 "--template", format,
         )
         if err != nil {
                 return
         }
         return strings.Split(s, ">", 5), nil
 }
+
+var revisionRe = regexp.MustCompile(`([0-9]+):[0-9a-f]+$`)
+
+// getTag fetches a Commit by finding the first hg tag that matches re.
+func getTag(re *regexp.Regexp) (c Commit, tag string, err os.Error) {
+        o, _, err := runLog(nil, "", goroot, "hg", "tags")
+        for _, l := range strings.Split(o, "\n", -1) {
+                tag = re.FindString(l)
+                if tag == "" {
+                        continue
+                }
+                s := revisionRe.FindStringSubmatch(l)
+                if s == nil {
+                        err = os.NewError("couldn't find revision number")
+                        return
+                }
+                c, err = getCommit(s[1])
+                return
+        }
+        err = os.NewError("no matching tag found")
+        return
+}