From e359b146aa7cb3039676760ba08e508933270390 Mon Sep 17 00:00:00 2001
From: Jakob Borg <jakob@nym.se>
Date: Mon, 19 May 2014 23:42:08 +0200
Subject: [PATCH] Properly handle read-write/read-only windows<->posix (fixes
 #236)

---
 model/puller.go | 20 +++++++++++++++-----
 model/util.go   |  2 ++
 scanner/walk.go | 21 +++++++++++++++++++--
 3 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/model/puller.go b/model/puller.go
index 9636f1f4..0fc360b7 100644
--- a/model/puller.go
+++ b/model/puller.go
@@ -525,19 +525,29 @@ func (p *puller) handleEmptyBlock(b bqBlock) {
 			l.Debugf("pull: delete %q", f.Name)
 		}
 		os.Remove(of.temp)
-		os.Remove(of.filepath)
+		os.Chmod(of.filepath, 0666)
+		if os.Remove(of.filepath) == nil {
+			p.model.updateLocal(p.repo, f)
+		}
 	} else {
 		if debug {
 			l.Debugf("pull: no blocks to fetch and nothing to copy for %q / %q", p.repo, f.Name)
 		}
 		t := time.Unix(f.Modified, 0)
-		os.Chtimes(of.temp, t, t)
-		os.Chmod(of.temp, os.FileMode(f.Flags&0777))
+		if os.Chtimes(of.temp, t, t) != nil {
+			delete(p.openFiles, f.Name)
+			return
+		}
+		if os.Chmod(of.temp, os.FileMode(f.Flags&0777)) != nil {
+			delete(p.openFiles, f.Name)
+			return
+		}
 		defTempNamer.Show(of.temp)
-		Rename(of.temp, of.filepath)
+		if Rename(of.temp, of.filepath) == nil {
+			p.model.updateLocal(p.repo, f)
+		}
 	}
 	delete(p.openFiles, f.Name)
-	p.model.updateLocal(p.repo, f)
 }
 
 func (p *puller) queueNeededBlocks() {
diff --git a/model/util.go b/model/util.go
index 38235f6c..e9290531 100644
--- a/model/util.go
+++ b/model/util.go
@@ -12,11 +12,13 @@ import (
 
 func Rename(from, to string) error {
 	if runtime.GOOS == "windows" {
+		os.Chmod(to, 0666) // Make sure the file is user writeable
 		err := os.Remove(to)
 		if err != nil && !os.IsNotExist(err) {
 			l.Warnln(err)
 		}
 	}
+	defer os.Remove(from) // Don't leave a dangling temp file in case of rename error
 	return os.Rename(from, to)
 }
 
diff --git a/scanner/walk.go b/scanner/walk.go
index b4db3b4b..a9465009 100644
--- a/scanner/walk.go
+++ b/scanner/walk.go
@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"time"
 
@@ -161,7 +162,7 @@ func (w *Walker) walkAndHashFiles(res *[]File, ign map[string][]string) filepath
 		if info.Mode().IsDir() {
 			if w.CurrentFiler != nil {
 				cf := w.CurrentFiler.CurrentFile(rn)
-				if cf.Modified == info.ModTime().Unix() && cf.Flags == uint32(info.Mode()&os.ModePerm|protocol.FlagDirectory) {
+				if cf.Modified == info.ModTime().Unix() && cf.Flags&protocol.FlagDirectory != 0 && permsEqual(cf.Flags, uint32(info.Mode())) {
 					if debug {
 						l.Debugln("unchanged:", cf)
 					}
@@ -185,7 +186,7 @@ func (w *Walker) walkAndHashFiles(res *[]File, ign map[string][]string) filepath
 		if info.Mode().IsRegular() {
 			if w.CurrentFiler != nil {
 				cf := w.CurrentFiler.CurrentFile(rn)
-				if cf.Flags&protocol.FlagDeleted == 0 && cf.Modified == info.ModTime().Unix() && cf.Flags == uint32(info.Mode()&os.ModePerm) {
+				if cf.Flags&protocol.FlagDeleted == 0 && cf.Modified == info.ModTime().Unix() && permsEqual(cf.Flags, uint32(info.Mode())) {
 					if debug {
 						l.Debugln("unchanged:", cf)
 					}
@@ -207,6 +208,10 @@ func (w *Walker) walkAndHashFiles(res *[]File, ign map[string][]string) filepath
 						l.Infof("Changes to %q are no longer suppressed.", p)
 					}
 				}
+
+				if debug {
+					l.Debugln("rescan:", cf, info.ModTime().Unix(), info.Mode()&os.ModePerm)
+				}
 			}
 
 			fd, err := os.Open(p)
@@ -277,3 +282,15 @@ func checkDir(dir string) error {
 	}
 	return nil
 }
+
+func permsEqual(a, b uint32) bool {
+	switch runtime.GOOS {
+	case "windows":
+		// There is only writeable and read only, represented for user, group
+		// and other equally. We only compare against user.
+		return a&0600 == b&0600
+	default:
+		// All bits count
+		return a&0777 == b&0777
+	}
+}