goinstall: support for Bazaar+Launchpad

With these changes, goinstall is now able to use branches
maintained with Bazaar located in Launchpad.

Project aliases such as /project and /project/series are
supported in addition to specific user or team branches
such as /~user/project/branch.  Temporary branches under
the +junk special project are also supported.

As a curious side effect, since Launchpad is able to import
code from other locations, they can be indirectly
accessible too if desired.

R=rsc
CC=golang-dev
https://golang.org/cl/1699050

src/cmd/goinstall/doc.go

@@ -42,6 +42,15 @@ if necessary.  The recognized code hosting sites are:
 		import "project.googlecode.com/svn/trunk"
 		import "project.googlecode.com/svn/trunk/sub/directory"
 
+	Launchpad
+
+		import "launchpad.net/project
+		import "launchpad.net/project/series
+		import "launchpad.net/project/series/sub/directory
+
+		import "launchpad.net/~user/project/branch
+		import "launchpad.net/~user/project/branch/sub/directory
+
 
 If the destination directory (e.g., $GOROOT/src/pkg/bitbucket.org/user/project)
 already exists and contains an appropriate checkout, goinstall will not

src/cmd/goinstall/download.go

@@ -34,6 +34,7 @@ func maybeReportToDashboard(path string) {
 var googlecode = regexp.MustCompile(`^([a-z0-9\-]+\.googlecode\.com/(svn|hg))(/[a-z0-9A-Z_.\-/]*)?$`)
 var github = regexp.MustCompile(`^(github\.com/[a-z0-9A-Z_.\-]+/[a-z0-9A-Z_.\-]+)(/[a-z0-9A-Z_.\-/]*)?$`)
 var bitbucket = regexp.MustCompile(`^(bitbucket\.org/[a-z0-9A-Z_.\-]+/[a-z0-9A-Z_.\-]+)(/[a-z0-9A-Z_.\-/]*)?$`)
+var launchpad = regexp.MustCompile(`^(launchpad\.net/([a-z0-9A-Z_.\-]+(/[a-z0-9A-Z_.\-]+)?|~[a-z0-9A-Z_.\-]+/(\+junk|[a-z0-9A-Z_.\-]+)/[a-z0-9A-Z_.\-]+))(/[a-z0-9A-Z_.\-/]+)?$`)
 
 // download checks out or updates pkg from the remote server.
 func download(pkg string) (string, os.Error) {
@@ -71,6 +72,14 @@ func download(pkg string) (string, os.Error) {
 		}
 		return root + pkg, nil
 	}
+	if m := launchpad.MatchStrings(pkg); m != nil {
+		// Either lp.net/<project>[/<series>[/<path>]]
+		//	 or lp.net/~<user or team>/<project>/<branch>[/<path>]
+		if err := vcsCheckout(&bzr, root+m[1], "https://"+m[1], m[1]); err != nil {
+			return "", err
+		}
+		return root + pkg, nil
+	}
 	return "", os.ErrorString("unknown repository: " + pkg)
 }
 
@@ -81,7 +90,9 @@ type vcs struct {
 	metadir           string
 	clone             string
 	update            string
+	updateReleaseFlag string
 	pull              string
+	pullForceFlag     string
 	log               string
 	logLimitFlag      string
 	logReleaseFlag    string
@@ -92,6 +103,7 @@ var hg = vcs{
 	metadir:           ".hg",
 	clone:             "clone",
 	update:            "update",
+	updateReleaseFlag: "release",
 	pull:              "pull",
 	log:               "log",
 	logLimitFlag:      "-l1",
@@ -103,6 +115,7 @@ var git = vcs{
 	metadir:           ".git",
 	clone:             "clone",
 	update:            "pull",
+	updateReleaseFlag: "release",
 	pull:              "fetch",
 	log:               "log",
 	logLimitFlag:      "-n1",
@@ -114,12 +127,25 @@ var svn = vcs{
 	metadir:           ".svn",
 	clone:             "checkout",
 	update:            "update",
-	pull:           "",
+	updateReleaseFlag: "release",
 	log:               "log",
 	logLimitFlag:      "-l1",
 	logReleaseFlag:    "release",
 }
 
+var bzr = vcs{
+	cmd:               "bzr",
+	metadir:           ".bzr",
+	clone:             "branch",
+	update:            "update",
+	updateReleaseFlag: "-rrelease",
+	pull:              "pull",
+	pullForceFlag:     "--overwrite",
+	log:               "log",
+	logLimitFlag:      "-l1",
+	logReleaseFlag:    "-rrelease",
+}
+
 // 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)
@@ -138,28 +164,38 @@ func vcsCheckout(vcs *vcs, dst, repo, dashpath string) os.Error {
 		if err := run("/", nil, vcs.cmd, vcs.clone, repo, dst); err != nil {
 			return err
 		}
-		quietRun(dst, nil, vcs.cmd, vcs.update, "release")
+		quietRun(dst, nil, vcs.cmd, vcs.update, vcs.updateReleaseFlag)
 
 		// success on first installation - report
 		maybeReportToDashboard(dashpath)
 	} else if *update {
+		// Retrieve new revisions from the remote branch, if the VCS
+		// supports this operation independently (e.g. svn doesn't)
 		if vcs.pull != "" {
-			if err := run(dst, nil, vcs.cmd, vcs.pull); err != nil {
+			if vcs.pullForceFlag != "" {
+				if err := run(dst, nil, vcs.cmd, vcs.pull, vcs.pullForceFlag); err != nil {
+					return err
+				}
+			} else 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
+
+		// Try to detect if a "release" tag exists.  If it does, update
+		// to the tagged version.  If no tag is found, then update to the
+		// tip afterwards.
+		// NOTE(gustavo@niemeyer.net): What is the expected behavior with
+		// svn here? "svn log -l1 release" doesn't make sense in this
+		// context and will probably fail.
 		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 {
+			if err := run(dst, nil, vcs.cmd, vcs.update, vcs.updateReleaseFlag); err != nil {
+				// The VCS supports tagging, has the "release" tag, but
+				// something else went wrong.  Report.
 				return err
 			}
-		} else {
-			if err := run(dst, nil, vcs.cmd, vcs.update); err != nil {
+		} else if err := run(dst, nil, vcs.cmd, vcs.update); err != nil {
 			return err
 		}
 	}
-	}
 	return nil
 }

src/cmd/goinstall/main.go

@@ -184,7 +184,7 @@ func quietRun(dir string, stdin []byte, cmd ...string) os.Error {
 	return genRun(dir, stdin, cmd, true)
 }
 
-// genRun implements run and tryRun.
+// genRun implements run and quietRun.
 func genRun(dir string, stdin []byte, cmd []string, quiet bool) os.Error {
 	bin, err := exec.LookPath(cmd[0])
 	if err != nil {