From fbf81bafe0d59061a79cd7bb95305c3ee9b1f70f Mon Sep 17 00:00:00 2001
From: Mikkel Krautz <mikkel@krautz.dk>
Date: Tue, 17 May 2011 20:23:28 +0200
Subject: [PATCH] Fix server freezing on Windows.

---
 freeze.go  | 25 ++++++++++++++++++++++++-
 grumble.go | 15 +++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/freeze.go b/freeze.go
index 596765e..b2909ce 100644
--- a/freeze.go
+++ b/freeze.go
@@ -13,6 +13,7 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+	"runtime"
 )
 
 type frozenServer struct {
@@ -64,7 +65,7 @@ type frozenGroup struct {
 	Remove      []int  "remove"
 }
 
-// Freeze a server and write it to a file
+// Freeze a server and write it to a file.
 func (server *Server) FreezeToFile(filename string) (err os.Error) {
 	r := server.FreezeServer()
 	if err != nil {
@@ -90,6 +91,28 @@ func (server *Server) FreezeToFile(filename string) (err os.Error) {
 	if err != nil {
 		return err
 	}
+	// Temporary non-atomic path
+	// We should probably use MoveFileEx instead, but I'm
+	// not sure whether that's atomic either. MoveFileTransacted
+	// would be prefered for Vista/Server 2008+.
+	if runtime.GOOS == "windows" {
+		err = os.Remove(filename + ".old")
+		if e, ok := err.(*os.PathError); ok {
+			if e.Error != os.ENOENT {
+				return err
+			}
+		} else if err != nil {
+			return err
+		}
+		err = os.Rename(filename, filename + ".old")
+		if e, ok := err.(*os.LinkError); ok {
+			if e.Error != os.ENOENT {
+				return err
+			}
+		} else if err != nil {
+			return err
+		}
+	}
 	err = os.Rename(f.Name(), filename)
 	if err != nil {
 		return err
diff --git a/grumble.go b/grumble.go
index 339dbf3..10f0b12 100644
--- a/grumble.go
+++ b/grumble.go
@@ -16,6 +16,7 @@ import (
 	"regexp"
 	"rpc"
 	"runtime"
+	"strconv"
 	"time"
 )
 
@@ -206,6 +207,20 @@ func main() {
 			servers[s.Id] = s
 			go s.ListenAndMurmur()
 		}
+		// win32 special-case
+		if matched, _ := regexp.MatchString("^[0-9]+.old$", name); matched {
+			sid, _ := strconv.Atoi64(name[0:len(name)-4])
+			_, exists := servers[sid]
+			if !exists {
+				log.Printf("Recovering lost server %v", name)
+				s, err := NewServerFromFrozen(filepath.Join(*datadir, name))
+				if err != nil {
+					log.Fatalf("Unable to recover server: %S", err.String())
+				}
+				servers[sid] = s
+				go s.ListenAndMurmur()
+			}
+		}
 	}
 
 	if len(servers) == 0 {