Refactor out upgrade package

upgrade/upgrade_common.go

@@ -0,0 +1,140 @@
+// 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.
+
+package upgrade
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+)
+
+type Release struct {
+	Tag        string  `json:"tag_name"`
+	Prerelease bool    `json:"prerelease"`
+	Assets     []Asset `json:"assets"`
+}
+
+type Asset struct {
+	URL  string `json:"url"`
+	Name string `json:"name"`
+}
+
+var (
+	ErrVersionUpToDate    = errors.New("current version is up to date")
+	ErrVersionUnknown     = errors.New("couldn't fetch release information")
+	ErrUpgradeUnsupported = errors.New("upgrade unsupported")
+)
+
+// Returns 1 if a>b, -1 if a<b and 0 if they are equal
+func CompareVersions(a, b string) int {
+	arel, apre := versionParts(a)
+	brel, bpre := versionParts(b)
+
+	minlen := len(arel)
+	if l := len(brel); l < minlen {
+		minlen = l
+	}
+
+	// First compare major-minor-patch versions
+	for i := 0; i < minlen; i++ {
+		if arel[i] < brel[i] {
+			return -1
+		}
+		if arel[i] > brel[i] {
+			return 1
+		}
+	}
+
+	// Longer version is newer, when the preceding parts are equal
+	if len(arel) < len(brel) {
+		return -1
+	}
+	if len(arel) > len(brel) {
+		return 1
+	}
+
+	// Prerelease versions are older, if the versions are the same
+	if len(apre) == 0 && len(bpre) > 0 {
+		return 1
+	}
+	if len(apre) > 0 && len(bpre) == 0 {
+		return -1
+	}
+
+	minlen = len(apre)
+	if l := len(bpre); l < minlen {
+		minlen = l
+	}
+
+	// Compare prerelease strings
+	for i := 0; i < minlen; i++ {
+		switch av := apre[i].(type) {
+		case int:
+			switch bv := bpre[i].(type) {
+			case int:
+				if av < bv {
+					return -1
+				}
+				if av > bv {
+					return 1
+				}
+			case string:
+				return -1
+			}
+		case string:
+			switch bv := bpre[i].(type) {
+			case int:
+				return 1
+			case string:
+				if av < bv {
+					return -1
+				}
+				if av > bv {
+					return 1
+				}
+			}
+		}
+	}
+
+	// If all else is equal, longer prerelease string is newer
+	if len(apre) < len(bpre) {
+		return -1
+	}
+	if len(apre) > len(bpre) {
+		return 1
+	}
+
+	// Looks like they're actually the same
+	return 0
+}
+
+// Split a version into parts.
+// "1.2.3-beta.2" -> []int{1, 2, 3}, []interface{}{"beta", 2}
+func versionParts(v string) ([]int, []interface{}) {
+	parts := strings.SplitN(v, "-", 2)
+	fields := strings.Split(parts[0], ".")
+
+	release := make([]int, len(fields))
+	for i, s := range fields {
+		v, _ := strconv.Atoi(s)
+		release[i] = v
+	}
+
+	var prerelease []interface{}
+	if len(parts) > 1 {
+		fields = strings.Split(parts[1], ".")
+		prerelease = make([]interface{}, len(fields))
+		for i, s := range fields {
+			v, err := strconv.Atoi(s)
+			if err == nil {
+				prerelease[i] = v
+			} else {
+				prerelease[i] = s
+			}
+		}
+	}
+
+	return release, prerelease
+}

upgrade/upgrade_supported.go

@@ -0,0 +1,145 @@
+// 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 !solaris,!windows,!noupgrade
+
+package upgrade
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"bitbucket.org/kardianos/osext"
+)
+
+var GoArchExtra string // "", "v5", "v6", "v7"
+
+// Upgrade to the given release, saving the previous binary with a ".old" extension.
+func UpgradeTo(rel Release) error {
+	path, err := osext.Executable()
+	if err != nil {
+		return err
+	}
+
+	expectedRelease := fmt.Sprintf("syncthing-%s-%s%s-%s.", runtime.GOOS, runtime.GOARCH, GoArchExtra, rel.Tag)
+	for _, asset := range rel.Assets {
+		if strings.HasPrefix(asset.Name, expectedRelease) {
+			if strings.HasSuffix(asset.Name, ".tar.gz") {
+				fname, err := readTarGZ(asset.URL, filepath.Dir(path))
+				if err != nil {
+					return err
+				}
+
+				old := path + ".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/calmh/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 readTarGZ(url string, dir string) (string, error) {
+	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()
+
+	gr, err := gzip.NewReader(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	tr := tar.NewReader(gr)
+	if err != nil {
+		return "", err
+	}
+
+	// Iterate through the files in the archive.
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			// end of tar archive
+			break
+		}
+		if err != nil {
+			return "", err
+		}
+
+		if path.Base(hdr.Name) == "syncthing" {
+			of, err := ioutil.TempFile(dir, "syncthing")
+			if err != nil {
+				return "", err
+			}
+			io.Copy(of, tr)
+			err = of.Close()
+			if err != nil {
+				os.Remove(of.Name())
+				return "", err
+			}
+
+			os.Chmod(of.Name(), os.FileMode(hdr.Mode))
+			return of.Name(), nil
+		}
+	}
+
+	return "", fmt.Errorf("No upgrade found")
+}

upgrade/upgrade_test.go

@@ -0,0 +1,39 @@
+// 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.
+
+package upgrade
+
+import "testing"
+
+var testcases = []struct {
+	a, b string
+	r    int
+}{
+	{"0.1.2", "0.1.2", 0},
+	{"0.1.3", "0.1.2", 1},
+	{"0.1.1", "0.1.2", -1},
+	{"0.3.0", "0.1.2", 1},
+	{"0.0.9", "0.1.2", -1},
+	{"1.1.2", "0.1.2", 1},
+	{"0.1.2", "1.1.2", -1},
+	{"0.1.10", "0.1.9", 1},
+	{"0.10.0", "0.2.0", 1},
+	{"30.10.0", "4.9.0", 1},
+	{"0.9.0-beta7", "0.9.0-beta6", 1},
+	{"1.0.0-alpha", "1.0.0-alpha.1", -1},
+	{"1.0.0-alpha.1", "1.0.0-alpha.beta", -1},
+	{"1.0.0-alpha.beta", "1.0.0-beta", -1},
+	{"1.0.0-beta", "1.0.0-beta.2", -1},
+	{"1.0.0-beta.2", "1.0.0-beta.11", -1},
+	{"1.0.0-beta.11", "1.0.0-rc.1", -1},
+	{"1.0.0-rc.1", "1.0.0", -1},
+}
+
+func TestCompareVersions(t *testing.T) {
+	for _, tc := range testcases {
+		if r := CompareVersions(tc.a, tc.b); r != tc.r {
+			t.Errorf("compareVersions(%q, %q): %d != %d", tc.a, tc.b, r, tc.r)
+		}
+	}
+}

upgrade/upgrade_unsupp.go

@@ -0,0 +1,15 @@
+// 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 solaris noupgrade
+
+package upgrade
+
+func Upgrade(current string) (Release, error) {
+	return Release{}, ErrUpgradeUnsupported
+}
+
+func LatestRelease(prerelease bool) (Release, error) {
+	return Release{}, ErrUpgradeUnsupported
+}