Add Windows upgrade support

upgrade/upgrade_unsupp.go

@@ -2,7 +2,7 @@
 // All rights reserved. Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
 
-// +build windows solaris noupgrade
+// +build solaris noupgrade
 
 package upgrade
 

upgrade/upgrade_windows.go

@@ -0,0 +1,166 @@
+// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
+// All rights reserved. Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build windows,!noupgrade
+
+package upgrade
+
+import (
+	"archive/zip"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"bitbucket.org/kardianos/osext"
+)
+
+// Upgrade to the given release, saving the previous binary with a ".old" extension.
+func UpgradeTo(rel Release, archExtra string) error {
+	path, err := osext.Executable()
+	if err != nil {
+		return err
+	}
+
+	expectedRelease := fmt.Sprintf("syncthing-%s-%s%s-%s.", runtime.GOOS, runtime.GOARCH, archExtra, rel.Tag)
+	if debug {
+		l.Debugf("expected release asset %q", expectedRelease)
+	}
+	for _, asset := range rel.Assets {
+		if debug {
+			l.Debugln("considering release", asset)
+		}
+		if strings.HasPrefix(asset.Name, expectedRelease) {
+			if strings.HasSuffix(asset.Name, ".zip") {
+				fname, err := readZip(asset.URL, filepath.Dir(path))
+				if err != nil {
+					return err
+				}
+
+				old := path + ".old"
+
+				os.Remove(old)
+				err = os.Rename(path, old)
+				if err != nil {
+					return err
+				}
+				err = os.Rename(fname, path)
+				if err != nil {
+					return err
+				}
+				return nil
+			}
+		}
+	}
+
+	return ErrVersionUnknown
+}
+
+// Returns the latest release, including prereleases or not depending on the argument
+func LatestRelease(prerelease bool) (Release, error) {
+	resp, err := http.Get("https://api.github.com/repos/syncthing/syncthing/releases?per_page=10")
+	if err != nil {
+		return Release{}, err
+	}
+	if resp.StatusCode > 299 {
+		return Release{}, fmt.Errorf("API call returned HTTP error: %s", resp.Status)
+	}
+
+	var rels []Release
+	json.NewDecoder(resp.Body).Decode(&rels)
+	resp.Body.Close()
+
+	if len(rels) == 0 {
+		return Release{}, ErrVersionUnknown
+	}
+
+	if prerelease {
+		// We are a beta version. Use the latest.
+		return rels[0], nil
+	} else {
+		// We are a regular release. Only consider non-prerelease versions for upgrade.
+		for _, rel := range rels {
+			if !rel.Prerelease {
+				return rel, nil
+			}
+		}
+		return Release{}, ErrVersionUnknown
+	}
+}
+
+func readZip(url, dir string) (string, error) {
+	if debug {
+		l.Debugf("loading %q", url)
+	}
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return "", err
+	}
+
+	req.Header.Add("Accept", "application/octet-stream")
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	archive, err := zip.NewReader(bytes.NewReader(body), resp.ContentLength)
+	if err != nil {
+		return "", err
+	}
+
+	// Iterate through the files in the archive.
+	for _, file := range archive.File {
+
+		if debug {
+			l.Debugf("considering file %q", file.Name)
+		}
+
+		if path.Base(file.Name) == "syncthing.exe" {
+			infile, err := file.Open()
+			if err != nil {
+				return "", err
+			}
+
+			outfile, err := ioutil.TempFile(dir, "syncthing")
+			if err != nil {
+				return "", err
+			}
+
+			_, err = io.Copy(outfile, infile)
+			if err != nil {
+				return "", err
+			}
+
+			err = infile.Close()
+			if err != nil {
+				return "", err
+			}
+
+			err = outfile.Close()
+			if err != nil {
+				os.Remove(outfile.Name())
+				return "", err
+			}
+
+			os.Chmod(outfile.Name(), file.Mode())
+			return outfile.Name(), nil
+		}
+	}
+
+	return "", fmt.Errorf("No upgrade found")
+}