code review 224043: goinstall: an experiment in (external) package installation

src/cmd/goinstall/download.go

+// Copyright 2010 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.
+
+// Download remote packages.
+
+package main
+
+import (
+        "http"
+        "os"
+        "regexp"
+        "strings"
+)
+
+const dashboardURL = "http://godashboard.appspot.com/package"
+
+// maybeReportToDashboard reports path to dashboard unless
+// -dashboard=false is on command line.  It ignores errors.
+func maybeReportToDashboard(path string) {
+        // if -dashboard=false was on command line, do nothing
+        if !*reportToDashboard {
+                return
+        }
+
+        // otherwise lob url to dashboard
+        r, _ := http.Post(dashboardURL, "application/x-www-form-urlencoded", strings.NewReader("path="+path))
+        if r != nil && r.Body != nil {
+                r.Body.Close()
+        }
+}
+
+var googlecode = regexp.MustCompile(`^([a-z0-9\-]+\.googlecode\.com/(svn|hg))(/[a-z0-9A-Z_.\-/]*)?$`)
+var github = regexp.MustCompile(`^(github\.com/[a-z0-9A-Z_.\-]+/[a-z0-9A-Z_.\-]+\.git)(/[a-z0-9A-Z_.\-/]*)?$`)
+var bitbucket = regexp.MustCompile(`^(bitbucket\.org/[a-z0-9A-Z_.\-]+/[a-z0-9A-Z_.\-]+)(/[a-z0-9A-Z_.\-/]*)?$`)
+
+// download checks out or updates pkg from the remote server.
+func download(pkg string) (string, os.Error) {
+        if strings.Index(pkg, "..") >= 0 {
+                return "", os.ErrorString("invalid path (contains ..)")
+        }
+        if m := bitbucket.MatchStrings(pkg); m != nil {
+                if err := vcsCheckout(&hg, root+m[1], "http://"+m[1], m[1]); err != nil {
+                        return "", err
+                }
+                return root + pkg, nil
+        }
+        if m := googlecode.MatchStrings(pkg); m != nil {
+                var v *vcs
+                switch m[2] {
+                case "hg":
+                        v = &hg
+                case "svn":
+                        v = &svn
+                default:
+                        // regexp only allows hg, svn to get through
+                        panic("missing case in download")

[r, 2010/03/03 04:21:55]

put pkg in the message

+                }
+                if err := vcsCheckout(v, root+m[1], "http://"+m[1], m[1]); err != nil {
+                        return "", err
+                }
+                return root + pkg, nil
+        }
+        if m := github.MatchStrings(pkg); m != nil {
+                if err := vcsCheckout(&git, root+m[1], "http://"+m[1], m[1]); err != nil {
+                        return "", err
+                }
+                return root + pkg, nil
+        }
+        return "", os.ErrorString("unknown repository: " + pkg)
+}
+
+type vcs struct {

[r, 2010/03/03 04:21:55]

if you want patches you should put comments on these things so they're easy to
understand by outsiders. also the FAQ should mention the file and hint at what
to do

+        cmd            string
+        metadir        string
+        clone          string
+        update         string
+        pull           string
+        log            string
+        logLimitFlag   string
+        logReleaseFlag string
+}
+
+var hg = vcs{
+        cmd: "hg",
+        metadir: ".hg",
+        clone: "clone",
+        update: "update",
+        pull: "pull",
+        log: "log",
+        logLimitFlag: "-l1",
+        logReleaseFlag: "-rrelease",
+}
+
+var git = vcs{
+        cmd: "git",
+        metadir: ".git",
+        clone: "clone",
+        update: "checkout",
+        pull: "fetch",
+        log: "log",
+        logLimitFlag: "-n1",
+        logReleaseFlag: "release",
+}
+
+var svn = vcs{
+        cmd: "svn",
+        metadir: ".svn",
+        clone: "checkout",
+        update: "update",
+        pull: "",
+        log: "log",
+        logLimitFlag: "-l1",
+        logReleaseFlag: "release",
+}
+
+// vcsCheckout checks out repo into dst using vcs.
+// It tries to check out (or update, if the dst already
+// exists and -u was specified on the command line)
+// the repository at tag/branch "release".  If there is no
+// such tag or branch, it falls back to the repository tip.
+func vcsCheckout(vcs *vcs, dst, repo, dashpath string) os.Error {
+        dir, err := os.Stat(dst + "/" + vcs.metadir)
+        if err == nil && !dir.IsDirectory() {
+                return os.ErrorString("not a directory: " + dst)
+        }
+        if err != nil {
+                if err := os.MkdirAll(dst, 0777); err != nil {
+                        return err
+                }
+                if err := run("/", nil, vcs.cmd, vcs.clone, repo, dst); err != nil {
+                        return err
+                }
+                quietRun(dst, nil, vcs.cmd, vcs.update, "release")
+
+                // success on first installation - report
+                maybeReportToDashboard(dashpath)
+        } else if *update {
+                if vcs.pull != "" {
+                        if err := run(dst, nil, vcs.cmd, vcs.pull); err != nil {
+                                return err
+                        }
+                }
+                // check for release with hg log -l 1 -r release
+                // if success, hg update release
+                // else hg update
+                if err := quietRun(dst, nil, vcs.cmd, vcs.log, vcs.logLimitFlag, vcs.logReleaseFlag); err == nil {
+                        if err := run(dst, nil, vcs.cmd, vcs.update, "release"); err != nil {
+                                return err
+                        }
+                } else {
+                        if err := run(dst, nil, vcs.cmd, vcs.update); err != nil {
+                                return err
+                        }
+                }
+        }
+        return nil
+}