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// Copyright 2012 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 vcs exposes functions for resolving import paths
// and using version control systems, which can be used to
// implement behavior similar to the standard "go get" command.
//
// This package is a copy of internal code in package cmd/go/internal/get,
// modified to make the identifiers exported. It's provided here
// for developers who want to write tools with similar semantics.
// It needs to be manually kept in sync with upstream when changes are
// made to cmd/go/internal/get; see https://golang.org/issue/11490.
//
package vcs // import "golang.org/x/tools/go/vcs"
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"log"
"net/url"
"os"
"os/exec"
"path/filepath"
"regexp"
"strconv"
"strings"
)
// Verbose enables verbose operation logging.
var Verbose bool
// ShowCmd controls whether VCS commands are printed.
var ShowCmd bool
// A Cmd describes how to use a version control system
// like Mercurial, Git, or Subversion.
type Cmd struct {
Name string
Cmd string // name of binary to invoke command
CreateCmd string // command to download a fresh copy of a repository
DownloadCmd string // command to download updates into an existing repository
TagCmd []TagCmd // commands to list tags
TagLookupCmd []TagCmd // commands to lookup tags before running tagSyncCmd
TagSyncCmd string // command to sync to specific tag
TagSyncDefault string // command to sync to default tag
LogCmd string // command to list repository changelogs in an XML format
Scheme []string
PingCmd string
}
// A TagCmd describes a command to list available tags
// that can be passed to Cmd.TagSyncCmd.
type TagCmd struct {
Cmd string // command to list tags
Pattern string // regexp to extract tags from list
}
// vcsList lists the known version control systems
var vcsList = []*Cmd{
vcsHg,
vcsGit,
vcsSvn,
vcsBzr,
}
// ByCmd returns the version control system for the given
// command name (hg, git, svn, bzr).
func ByCmd(cmd string) *Cmd {
for _, vcs := range vcsList {
if vcs.Cmd == cmd {
return vcs
}
}
return nil
}
// vcsHg describes how to use Mercurial.
var vcsHg = &Cmd{
Name: "Mercurial",
Cmd: "hg",
CreateCmd: "clone -U {repo} {dir}",
DownloadCmd: "pull",
// We allow both tag and branch names as 'tags'
// for selecting a version. This lets people have
// a go.release.r60 branch and a go1 branch
// and make changes in both, without constantly
// editing .hgtags.
TagCmd: []TagCmd{
{"tags", `^(\S+)`},
{"branches", `^(\S+)`},
},
TagSyncCmd: "update -r {tag}",
TagSyncDefault: "update default",
LogCmd: "log --encoding=utf-8 --limit={limit} --template={template}",
Scheme: []string{"https", "http", "ssh"},
PingCmd: "identify {scheme}://{repo}",
}
// vcsGit describes how to use Git.
var vcsGit = &Cmd{
Name: "Git",
Cmd: "git",
CreateCmd: "clone {repo} {dir}",
DownloadCmd: "pull --ff-only",
TagCmd: []TagCmd{
// tags/xxx matches a git tag named xxx
// origin/xxx matches a git branch named xxx on the default remote repository
{"show-ref", `(?:tags|origin)/(\S+)$`},
},
TagLookupCmd: []TagCmd{
{"show-ref tags/{tag} origin/{tag}", `((?:tags|origin)/\S+)$`},
},
TagSyncCmd: "checkout {tag}",
TagSyncDefault: "checkout master",
Scheme: []string{"git", "https", "http", "git+ssh"},
PingCmd: "ls-remote {scheme}://{repo}",
}
// vcsBzr describes how to use Bazaar.
var vcsBzr = &Cmd{
Name: "Bazaar",
Cmd: "bzr",
CreateCmd: "branch {repo} {dir}",
// Without --overwrite bzr will not pull tags that changed.
// Replace by --overwrite-tags after http://pad.lv/681792 goes in.
DownloadCmd: "pull --overwrite",
TagCmd: []TagCmd{{"tags", `^(\S+)`}},
TagSyncCmd: "update -r {tag}",
TagSyncDefault: "update -r revno:-1",
Scheme: []string{"https", "http", "bzr", "bzr+ssh"},
PingCmd: "info {scheme}://{repo}",
}
// vcsSvn describes how to use Subversion.
var vcsSvn = &Cmd{
Name: "Subversion",
Cmd: "svn",
CreateCmd: "checkout {repo} {dir}",
DownloadCmd: "update",
// There is no tag command in subversion.
// The branch information is all in the path names.
LogCmd: "log --xml --limit={limit}",
Scheme: []string{"https", "http", "svn", "svn+ssh"},
PingCmd: "info {scheme}://{repo}",
}
func (v *Cmd) String() string {
return v.Name
}
// run runs the command line cmd in the given directory.
// keyval is a list of key, value pairs. run expands
// instances of {key} in cmd into value, but only after
// splitting cmd into individual arguments.
// If an error occurs, run prints the command line and the
// command's combined stdout+stderr to standard error.
// Otherwise run discards the command's output.
func (v *Cmd) run(dir string, cmd string, keyval ...string) error {
_, err := v.run1(dir, cmd, keyval, true)
return err
}
// runVerboseOnly is like run but only generates error output to standard error in verbose mode.
func (v *Cmd) runVerboseOnly(dir string, cmd string, keyval ...string) error {
_, err := v.run1(dir, cmd, keyval, false)
return err
}
// runOutput is like run but returns the output of the command.
func (v *Cmd) runOutput(dir string, cmd string, keyval ...string) ([]byte, error) {
return v.run1(dir, cmd, keyval, true)
}
// run1 is the generalized implementation of run and runOutput.
func (v *Cmd) run1(dir string, cmdline string, keyval []string, verbose bool) ([]byte, error) {
m := make(map[string]string)
for i := 0; i < len(keyval); i += 2 {
m[keyval[i]] = keyval[i+1]
}
args := strings.Fields(cmdline)
for i, arg := range args {
args[i] = expand(m, arg)
}
_, err := exec.LookPath(v.Cmd)
if err != nil {
fmt.Fprintf(os.Stderr,
"go: missing %s command. See http://golang.org/s/gogetcmd\n",
v.Name)
return nil, err
}
cmd := exec.Command(v.Cmd, args...)
cmd.Dir = dir
cmd.Env = envForDir(cmd.Dir)
if ShowCmd {
fmt.Printf("cd %s\n", dir)
fmt.Printf("%s %s\n", v.Cmd, strings.Join(args, " "))
}
var buf bytes.Buffer
cmd.Stdout = &buf
cmd.Stderr = &buf
err = cmd.Run()
out := buf.Bytes()
if err != nil {
if verbose || Verbose {
fmt.Fprintf(os.Stderr, "# cd %s; %s %s\n", dir, v.Cmd, strings.Join(args, " "))
os.Stderr.Write(out)
}
return nil, err
}
return out, nil
}
// Ping pings the repo to determine if scheme used is valid.
// This repo must be pingable with this scheme and VCS.
func (v *Cmd) Ping(scheme, repo string) error {
return v.runVerboseOnly(".", v.PingCmd, "scheme", scheme, "repo", repo)
}
// Create creates a new copy of repo in dir.
// The parent of dir must exist; dir must not.
func (v *Cmd) Create(dir, repo string) error {
return v.run(".", v.CreateCmd, "dir", dir, "repo", repo)
}
// CreateAtRev creates a new copy of repo in dir at revision rev.
// The parent of dir must exist; dir must not.
// rev must be a valid revision in repo.
func (v *Cmd) CreateAtRev(dir, repo, rev string) error {
if err := v.Create(dir, repo); err != nil {
return err
}
return v.run(dir, v.TagSyncCmd, "tag", rev)
}
// Download downloads any new changes for the repo in dir.
// dir must be a valid VCS repo compatible with v.
func (v *Cmd) Download(dir string) error {
return v.run(dir, v.DownloadCmd)
}
// Tags returns the list of available tags for the repo in dir.
// dir must be a valid VCS repo compatible with v.
func (v *Cmd) Tags(dir string) ([]string, error) {
var tags []string
for _, tc := range v.TagCmd {
out, err := v.runOutput(dir, tc.Cmd)
if err != nil {
return nil, err
}
re := regexp.MustCompile(`(?m-s)` + tc.Pattern)
for _, m := range re.FindAllStringSubmatch(string(out), -1) {
tags = append(tags, m[1])
}
}
return tags, nil
}
// TagSync syncs the repo in dir to the named tag, which is either a
// tag returned by Tags or the empty string (the default tag).
// dir must be a valid VCS repo compatible with v and the tag must exist.
func (v *Cmd) TagSync(dir, tag string) error {
if v.TagSyncCmd == "" {
return nil
}
if tag != "" {
for _, tc := range v.TagLookupCmd {
out, err := v.runOutput(dir, tc.Cmd, "tag", tag)
if err != nil {
return err
}
re := regexp.MustCompile(`(?m-s)` + tc.Pattern)
m := re.FindStringSubmatch(string(out))
if len(m) > 1 {
tag = m[1]
break
}
}
}
if tag == "" && v.TagSyncDefault != "" {
return v.run(dir, v.TagSyncDefault)
}
return v.run(dir, v.TagSyncCmd, "tag", tag)
}
// Log logs the changes for the repo in dir.
// dir must be a valid VCS repo compatible with v.
func (v *Cmd) Log(dir, logTemplate string) ([]byte, error) {
if err := v.Download(dir); err != nil {
return []byte{}, err
}
const N = 50 // how many revisions to grab
return v.runOutput(dir, v.LogCmd, "limit", strconv.Itoa(N), "template", logTemplate)
}
// LogAtRev logs the change for repo in dir at the rev revision.
// dir must be a valid VCS repo compatible with v.
// rev must be a valid revision for the repo in dir.
func (v *Cmd) LogAtRev(dir, rev, logTemplate string) ([]byte, error) {
if err := v.Download(dir); err != nil {
return []byte{}, err
}
// Append revision flag to LogCmd.
logAtRevCmd := v.LogCmd + " --rev=" + rev
return v.runOutput(dir, logAtRevCmd, "limit", strconv.Itoa(1), "template", logTemplate)
}
// A vcsPath describes how to convert an import path into a
// version control system and repository name.
type vcsPath struct {
prefix string // prefix this description applies to
re string // pattern for import path
repo string // repository to use (expand with match of re)
vcs string // version control system to use (expand with match of re)
check func(match map[string]string) error // additional checks
ping bool // ping for scheme to use to download repo
regexp *regexp.Regexp // cached compiled form of re
}
// FromDir inspects dir and its parents to determine the
// version control system and code repository to use.
// On return, root is the import path
// corresponding to the root of the repository.
func FromDir(dir, srcRoot string) (vcs *Cmd, root string, err error) {
// Clean and double-check that dir is in (a subdirectory of) srcRoot.
dir = filepath.Clean(dir)
srcRoot = filepath.Clean(srcRoot)
if len(dir) <= len(srcRoot) || dir[len(srcRoot)] != filepath.Separator {
return nil, "", fmt.Errorf("directory %q is outside source root %q", dir, srcRoot)
}
var vcsRet *Cmd
var rootRet string
origDir := dir
for len(dir) > len(srcRoot) {
for _, vcs := range vcsList {
if _, err := os.Stat(filepath.Join(dir, "."+vcs.Cmd)); err == nil {
root := filepath.ToSlash(dir[len(srcRoot)+1:])
// Record first VCS we find, but keep looking,
// to detect mistakes like one kind of VCS inside another.
if vcsRet == nil {
vcsRet = vcs
rootRet = root
continue
}
// Allow .git inside .git, which can arise due to submodules.
if vcsRet == vcs && vcs.Cmd == "git" {
continue
}
// Otherwise, we have one VCS inside a different VCS.
return nil, "", fmt.Errorf("directory %q uses %s, but parent %q uses %s",
filepath.Join(srcRoot, rootRet), vcsRet.Cmd, filepath.Join(srcRoot, root), vcs.Cmd)
}
}
// Move to parent.
ndir := filepath.Dir(dir)
if len(ndir) >= len(dir) {
// Shouldn't happen, but just in case, stop.
break
}
dir = ndir
}
if vcsRet != nil {
return vcsRet, rootRet, nil
}
return nil, "", fmt.Errorf("directory %q is not using a known version control system", origDir)
}
// RepoRoot represents a version control system, a repo, and a root of
// where to put it on disk.
type RepoRoot struct {
VCS *Cmd
// Repo is the repository URL, including scheme.
Repo string
// Root is the import path corresponding to the root of the
// repository.
Root string
}
// RepoRootForImportPath analyzes importPath to determine the
// version control system, and code repository to use.
func RepoRootForImportPath(importPath string, verbose bool) (*RepoRoot, error) {
rr, err := RepoRootForImportPathStatic(importPath, "")
if err == errUnknownSite {
rr, err = RepoRootForImportDynamic(importPath, verbose)
// RepoRootForImportDynamic returns error detail
// that is irrelevant if the user didn't intend to use a
// dynamic import in the first place.
// Squelch it.
if err != nil {
if Verbose {
log.Printf("import %q: %v", importPath, err)
}
err = fmt.Errorf("unrecognized import path %q", importPath)
}
}
if err == nil && strings.Contains(importPath, "...") && strings.Contains(rr.Root, "...") {
// Do not allow wildcards in the repo root.
rr = nil
err = fmt.Errorf("cannot expand ... in %q", importPath)
}
return rr, err
}
var errUnknownSite = errors.New("dynamic lookup required to find mapping")
// RepoRootForImportPathStatic attempts to map importPath to a
// RepoRoot using the commonly-used VCS hosting sites in vcsPaths
// (github.com/user/dir), or from a fully-qualified importPath already
// containing its VCS type (foo.com/repo.git/dir)
//
// If scheme is non-empty, that scheme is forced.
func RepoRootForImportPathStatic(importPath, scheme string) (*RepoRoot, error) {
if strings.Contains(importPath, "://") {
return nil, fmt.Errorf("invalid import path %q", importPath)
}
for _, srv := range vcsPaths {
if !strings.HasPrefix(importPath, srv.prefix) {
continue
}
m := srv.regexp.FindStringSubmatch(importPath)
if m == nil {
if srv.prefix != "" {
return nil, fmt.Errorf("invalid %s import path %q", srv.prefix, importPath)
}
continue
}
// Build map of named subexpression matches for expand.
match := map[string]string{
"prefix": srv.prefix,
"import": importPath,
}
for i, name := range srv.regexp.SubexpNames() {
if name != "" && match[name] == "" {
match[name] = m[i]
}
}
if srv.vcs != "" {
match["vcs"] = expand(match, srv.vcs)
}
if srv.repo != "" {
match["repo"] = expand(match, srv.repo)
}
if srv.check != nil {
if err := srv.check(match); err != nil {
return nil, err
}
}
vcs := ByCmd(match["vcs"])
if vcs == nil {
return nil, fmt.Errorf("unknown version control system %q", match["vcs"])
}
if srv.ping {
if scheme != "" {
match["repo"] = scheme + "://" + match["repo"]
} else {
for _, scheme := range vcs.Scheme {
if vcs.Ping(scheme, match["repo"]) == nil {
match["repo"] = scheme + "://" + match["repo"]
break
}
}
}
}
rr := &RepoRoot{
VCS: vcs,
Repo: match["repo"],
Root: match["root"],
}
return rr, nil
}
return nil, errUnknownSite
}
// RepoRootForImportDynamic finds a *RepoRoot for a custom domain that's not
// statically known by RepoRootForImportPathStatic.
//
// This handles custom import paths like "name.tld/pkg/foo" or just "name.tld".
func RepoRootForImportDynamic(importPath string, verbose bool) (*RepoRoot, error) {
slash := strings.Index(importPath, "/")
if slash < 0 {
slash = len(importPath)
}
host := importPath[:slash]
if !strings.Contains(host, ".") {
return nil, errors.New("import path doesn't contain a hostname")
}
urlStr, body, err := httpsOrHTTP(importPath)
if err != nil {
return nil, fmt.Errorf("http/https fetch: %v", err)
}
defer body.Close()
imports, err := parseMetaGoImports(body)
if err != nil {
return nil, fmt.Errorf("parsing %s: %v", importPath, err)
}
metaImport, err := matchGoImport(imports, importPath)
if err != nil {
if err != errNoMatch {
return nil, fmt.Errorf("parse %s: %v", urlStr, err)
}
return nil, fmt.Errorf("parse %s: no go-import meta tags", urlStr)
}
if verbose {
log.Printf("get %q: found meta tag %#v at %s", importPath, metaImport, urlStr)
}
// If the import was "uni.edu/bob/project", which said the
// prefix was "uni.edu" and the RepoRoot was "evilroot.com",
// make sure we don't trust Bob and check out evilroot.com to
// "uni.edu" yet (possibly overwriting/preempting another
// non-evil student). Instead, first verify the root and see
// if it matches Bob's claim.
if metaImport.Prefix != importPath {
if verbose {
log.Printf("get %q: verifying non-authoritative meta tag", importPath)
}
urlStr0 := urlStr
urlStr, body, err = httpsOrHTTP(metaImport.Prefix)
if err != nil {
return nil, fmt.Errorf("fetch %s: %v", urlStr, err)
}
imports, err := parseMetaGoImports(body)
if err != nil {
return nil, fmt.Errorf("parsing %s: %v", importPath, err)
}
if len(imports) == 0 {
return nil, fmt.Errorf("fetch %s: no go-import meta tag", urlStr)
}
metaImport2, err := matchGoImport(imports, importPath)
if err != nil || metaImport != metaImport2 {
return nil, fmt.Errorf("%s and %s disagree about go-import for %s", urlStr0, urlStr, metaImport.Prefix)
}
}
if err := validateRepoRoot(metaImport.RepoRoot); err != nil {
return nil, fmt.Errorf("%s: invalid repo root %q: %v", urlStr, metaImport.RepoRoot, err)
}
rr := &RepoRoot{
VCS: ByCmd(metaImport.VCS),
Repo: metaImport.RepoRoot,
Root: metaImport.Prefix,
}
if rr.VCS == nil {
return nil, fmt.Errorf("%s: unknown vcs %q", urlStr, metaImport.VCS)
}
return rr, nil
}
// validateRepoRoot returns an error if repoRoot does not seem to be
// a valid URL with scheme.
func validateRepoRoot(repoRoot string) error {
url, err := url.Parse(repoRoot)
if err != nil {
return err
}
if url.Scheme == "" {
return errors.New("no scheme")
}
return nil
}
// metaImport represents the parsed <meta name="go-import"
// content="prefix vcs reporoot" /> tags from HTML files.
type metaImport struct {
Prefix, VCS, RepoRoot string
}
// errNoMatch is returned from matchGoImport when there's no applicable match.
var errNoMatch = errors.New("no import match")
// pathPrefix reports whether sub is a prefix of s,
// only considering entire path components.
func pathPrefix(s, sub string) bool {
// strings.HasPrefix is necessary but not sufficient.
if !strings.HasPrefix(s, sub) {
return false
}
// The remainder after the prefix must either be empty or start with a slash.
rem := s[len(sub):]
return rem == "" || rem[0] == '/'
}
// matchGoImport returns the metaImport from imports matching importPath.
// An error is returned if there are multiple matches.
// errNoMatch is returned if none match.
func matchGoImport(imports []metaImport, importPath string) (_ metaImport, err error) {
match := -1
for i, im := range imports {
if !pathPrefix(importPath, im.Prefix) {
continue
}
if match != -1 {
err = fmt.Errorf("multiple meta tags match import path %q", importPath)
return
}
match = i
}
if match == -1 {
err = errNoMatch
return
}
return imports[match], nil
}
// expand rewrites s to replace {k} with match[k] for each key k in match.
func expand(match map[string]string, s string) string {
for k, v := range match {
s = strings.Replace(s, "{"+k+"}", v, -1)
}
return s
}
// vcsPaths lists the known vcs paths.
var vcsPaths = []*vcsPath{
// Github
{
prefix: "github.com/",
re: `^(?P<root>github\.com/[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+)(/[\p{L}0-9_.\-]+)*$`,
vcs: "git",
repo: "https://{root}",
check: noVCSSuffix,
},
// Bitbucket
{
prefix: "bitbucket.org/",
re: `^(?P<root>bitbucket\.org/(?P<bitname>[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+))(/[A-Za-z0-9_.\-]+)*$`,
repo: "https://{root}",
check: bitbucketVCS,
},
// Launchpad
{
prefix: "launchpad.net/",
re: `^(?P<root>launchpad\.net/((?P<project>[A-Za-z0-9_.\-]+)(?P<series>/[A-Za-z0-9_.\-]+)?|~[A-Za-z0-9_.\-]+/(\+junk|[A-Za-z0-9_.\-]+)/[A-Za-z0-9_.\-]+))(/[A-Za-z0-9_.\-]+)*$`,
vcs: "bzr",
repo: "https://{root}",
check: launchpadVCS,
},
// Git at OpenStack
{
prefix: "git.openstack.org",
re: `^(?P<root>git\.openstack\.org/[A-Za-z0-9_.\-]+/[A-Za-z0-9_.\-]+)(\.git)?(/[A-Za-z0-9_.\-]+)*$`,
vcs: "git",
repo: "https://{root}",
check: noVCSSuffix,
},
// General syntax for any server.
{
re: `^(?P<root>(?P<repo>([a-z0-9.\-]+\.)+[a-z0-9.\-]+(:[0-9]+)?/[A-Za-z0-9_.\-/]*?)\.(?P<vcs>bzr|git|hg|svn))(/[A-Za-z0-9_.\-]+)*$`,
ping: true,
},
}
func init() {
// fill in cached regexps.
// Doing this eagerly discovers invalid regexp syntax
// without having to run a command that needs that regexp.
for _, srv := range vcsPaths {
srv.regexp = regexp.MustCompile(srv.re)
}
}
// noVCSSuffix checks that the repository name does not
// end in .foo for any version control system foo.
// The usual culprit is ".git".
func noVCSSuffix(match map[string]string) error {
repo := match["repo"]
for _, vcs := range vcsList {
if strings.HasSuffix(repo, "."+vcs.Cmd) {
return fmt.Errorf("invalid version control suffix in %s path", match["prefix"])
}
}
return nil
}
// bitbucketVCS determines the version control system for a
// Bitbucket repository, by using the Bitbucket API.
func bitbucketVCS(match map[string]string) error {
if err := noVCSSuffix(match); err != nil {
return err
}
var resp struct {
SCM string `json:"scm"`
}
url := expand(match, "https://api.bitbucket.org/2.0/repositories/{bitname}?fields=scm")
data, err := httpGET(url)
if err != nil {
return err
}
if err := json.Unmarshal(data, &resp); err != nil {
return fmt.Errorf("decoding %s: %v", url, err)
}
if ByCmd(resp.SCM) != nil {
match["vcs"] = resp.SCM
if resp.SCM == "git" {
match["repo"] += ".git"
}
return nil
}
return fmt.Errorf("unable to detect version control system for bitbucket.org/ path")
}
// launchpadVCS solves the ambiguity for "lp.net/project/foo". In this case,
// "foo" could be a series name registered in Launchpad with its own branch,
// and it could also be the name of a directory within the main project
// branch one level up.
func launchpadVCS(match map[string]string) error {
if match["project"] == "" || match["series"] == "" {
return nil
}
_, err := httpGET(expand(match, "https://code.launchpad.net/{project}{series}/.bzr/branch-format"))
if err != nil {
match["root"] = expand(match, "launchpad.net/{project}")
match["repo"] = expand(match, "https://{root}")
}
return nil
}