code review 7326053: misc/dashboard/builder: various cleanups

misc/dashboard/builder/vcs.go

 // Copyright 2013 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 (
         "encoding/xml"
         "fmt"
         "log"
         "os"
         "path/filepath"
         "strconv"
         "strings"
         "sync"
 )
 
-// Repo represents a mercurial repository
+// Repo represents a mercurial repository.
 type Repo struct {
         Path string
         sync.Mutex
 }
 
-// RemoteRepo constructs a *Repo representing a remote URL
+// RemoteRepo constructs a *Repo representing a remote repository.
 func RemoteRepo(url string) *Repo {
         return &Repo{
                 Path: url,
         }
 }
 
 // Clone clones the current Repo to a new destination
-// returning a new *Repo if successful
+// returning a new *Repo if successful.
 func (r *Repo) Clone(path, rev string) (*Repo, error) {
         r.Lock()
         defer r.Unlock()
         if err := run(*cmdTimeout, nil, *buildroot, r.hgCmd("clone", "-r", rev, r.Path, path)...); err != nil {
                 return nil, err
         }
         return &Repo{
                 Path: path,
         }, nil
 }
 
 // UpdateTo updates the working copy of this Repo to the
 // supplied revision.
 func (r *Repo) UpdateTo(hash string) error {
         r.Lock()
         defer r.Unlock()
         return run(*cmdTimeout, nil, r.Path, r.hgCmd("update", hash)...)
 }
 
 // Exists reports whether this Repo represents a valid Mecurial repository.
 func (r *Repo) Exists() bool {
-        // TODO(dfc) probably don't need to lock here
         fi, err := os.Stat(filepath.Join(r.Path, ".hg"))
         if err != nil {
                 return false
         }
         return fi.IsDir()
 }
 
 // Pull pulls changes from the default path, that is, the path
 // this Repo was cloned from.
 func (r *Repo) Pull() error {
         r.Lock()
         defer r.Unlock()
         return run(*cmdTimeout, nil, r.Path, r.hgCmd("pull")...)
 }
 
 // Log returns the changelog for this repository.
 func (r *Repo) Log() ([]HgLog, error) {
+        if err := r.Pull(); err != nil {
+                return nil, err
+        }
         const N = 50 // how many revisions to grab
 
         r.Lock()
         defer r.Unlock()
         data, _, err := runLog(*cmdTimeout, nil, r.Path, r.hgCmd("log",
                 "--encoding=utf-8",
                 "--limit="+strconv.Itoa(N),
                 "--template="+xmlLogTemplate)...,
         )
         if err != nil {
@@ skipping 44 matching lines @@
         Hash   string
         Author string
         Date   string
         Desc   string
         Parent string
 
         // Internal metadata
         added bool
 }
 
-// logByHash is a cache of all Mercurial revisions we know about,
-// indexed by full hash.
-var logByHash = map[string]*HgLog{}
-
 // xmlLogTemplate is a template to pass to Mercurial to make
 // hg log print the log in valid XML for parsing with xml.Unmarshal.
 const xmlLogTemplate = `
         <Log>
         <Hash>{node|escape}</Hash>
         <Parent>{parent|escape}</Parent>
         <Author>{author|escape}</Author>
         <Date>{date|rfc3339date}</Date>
         <Desc>{desc|escape}</Desc>
         </Log>
 `