goinstall: added -a flag to mean "all remote packages"

Fixes #897.

goinstall -a can be used to reinstall all packages after an upgrade
goinstall -a -u can be used to update all package
A history of remote package installs is stored in $GOROOT/goinstall.log

R=rsc, adg
CC=golang-dev
https://golang.org/cl/1947041

.hgignore

@@ -40,6 +40,7 @@ test/pass.out
 test/run.out
 test/times.out
 test/garbage/*.out
+goinstall.log
 
 syntax:regexp
 ^bin/

src/cmd/goinstall/doc.go

@@ -10,14 +10,33 @@ It maintains a list of public Go packages at http://godashboard.appspot.com/pack
 
 Usage:
 	goinstall [flags] importpath...
+	goinstall [flags] -a
 
 Flags and default settings:
+        -a=false          install all previously installed packages
 	-dashboard=true   tally public packages on godashboard.appspot.com
-	-update=false     update already-downloaded packages
+	-log=true         log installed packages to $GOROOT/goinstall.log for use by -a
+	-u=false          update already-downloaded packages
 	-v=false          verbose operation
 
-Goinstall installs each of the packages identified on the command line.
-It installs a package's prerequisites before trying to install the package itself.
+Goinstall installs each of the packages identified on the command line.  It
+installs a package's prerequisites before trying to install the package
+itself. Unless -log=false is specified, goinstall logs the import path of each
+installed package to $GOROOT/goinstall.log for use by goinstall -a.
+
+If the -a flag is given, goinstall reinstalls all previously installed
+packages, reading the list from $GOROOT/goinstall.log.  After updating to a
+new Go release, which deletes all package binaries, running
+
+	goinstall -a
+
+will recompile and reinstall goinstalled packages.
+
+Another common idiom is to use
+
+	goinstall -a -u
+
+to update, recompile, and reinstall all goinstalled packages.
 
 The source code for a package with import path foo/bar is expected
 to be in the directory $GOROOT/src/pkg/foo/bar/.  If the import
@@ -54,7 +73,7 @@ if necessary.  The recognized code hosting sites are:
 
 If the destination directory (e.g., $GOROOT/src/pkg/bitbucket.org/user/project)
 already exists and contains an appropriate checkout, goinstall will not
-attempt to fetch updates.  The -update flag changes this behavior,
+attempt to fetch updates.  The -u flag changes this behavior,
 causing goinstall to update all remote packages encountered during
 the installation.
 

src/cmd/goinstall/main.go

@@ -12,6 +12,7 @@ import (
 	"flag"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
 	"path"
 	"runtime"
@@ -20,19 +21,24 @@ import (
 
 func usage() {
 	fmt.Fprint(os.Stderr, "usage: goinstall importpath...\n")
+	fmt.Fprintf(os.Stderr, "\tgoinstall -a\n")
 	flag.PrintDefaults()
 	os.Exit(2)
 }
 
 var (
-	argv0   = os.Args[0]
-	errors  = false
-	gobin   = os.Getenv("GOBIN")
-	parents = make(map[string]string)
-	root    = runtime.GOROOT()
-	visit   = make(map[string]status)
+	argv0         = os.Args[0]
+	errors        = false
+	gobin         = os.Getenv("GOBIN")
+	parents       = make(map[string]string)
+	root          = runtime.GOROOT()
+	visit         = make(map[string]status)
+	logfile       = path.Join(root, "goinstall.log")
+	installedPkgs = make(map[string]bool)
 
+	allpkg            = flag.Bool("a", false, "install all previously installed packages")
 	reportToDashboard = flag.Bool("dashboard", true, "report public packages at "+dashboardURL)
+	logPkgs           = flag.Bool("log", true, "log installed packages to $GOROOT/goinstall.log for use by -a")
 	update            = flag.Bool("u", false, "update already-downloaded packages")
 	verbose           = flag.Bool("v", false, "verbose")
 )
@@ -59,8 +65,26 @@ func main() {
 	// special case - "unsafe" is already installed
 	visit["unsafe"] = done
 
-	// install command line arguments
 	args := flag.Args()
+	if *allpkg || *logPkgs {
+		readPackageList()
+	}
+	if *allpkg {
+		if len(args) != 0 {
+			usage() // -a and package list both provided
+		}
+		// install all packages that were ever installed
+		if len(installedPkgs) == 0 {
+			fmt.Fprintf(os.Stderr, "%s: no installed packages\n", argv0)
+			os.Exit(1)
+		}
+		args = make([]string, len(installedPkgs), len(installedPkgs))
+		i := 0
+		for pkg := range installedPkgs {
+			args[i] = pkg
+			i++
+		}
+	}
 	if len(args) == 0 {
 		usage()
 	}
@@ -83,6 +107,29 @@ func printDeps(pkg string) {
 	fmt.Fprintf(os.Stderr, "\t%s ->\n", pkg)
 }
 
+// readPackageList reads the list of installed packages from goinstall.log
+func readPackageList() {
+	pkglistdata, _ := ioutil.ReadFile(logfile)
+	pkglist := strings.Fields(string(pkglistdata))
+	for _, pkg := range pkglist {
+		installedPkgs[pkg] = true
+	}
+}
+
+// logPackage logs the named package as installed in goinstall.log, if the package is not found in there
+func logPackage(pkg string) {
+	if installedPkgs[pkg] {
+		return
+	}
+	fout, err := os.Open(logfile, os.O_WRONLY|os.O_APPEND|os.O_CREAT, 0644)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: %s\n", argv0, err)
+		return
+	}
+	fmt.Fprintf(fout, "%s\n", pkg)
+	fout.Close()
+}
+
 // install installs the package named by path, which is needed by parent.
 func install(pkg, parent string) {
 	// Make sure we're not already trying to install pkg.
@@ -153,9 +200,11 @@ func install(pkg, parent string) {
 		if err := domake(dir, pkg, local); err != nil {
 			fmt.Fprintf(os.Stderr, "%s: installing %s: %s\n", argv0, pkg, err)
 			errors = true
+		} else if !local && *logPkgs {
+			// mark this package as installed in $GOROOT/goinstall.log
+			logPackage(pkg)
 		}
 	}
-
 	visit[pkg] = done
 }