1 files changed, 186 insertions, 0 deletions
diff --git a/src/cmd/api/run.go b/src/cmd/api/run.go
new file mode 100644
index 000000000..1e10dc600
--- /dev/null
+++ b/src/cmd/api/run.go
@@ -0,0 +1,186 @@
+// Copyright 2013 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.
+
+// +build ignore
+
+// The run program is invoked via "go run" from src/run.bash or
+// src/run.bat conditionally builds and runs the cmd/api tool.
+//
+// TODO(bradfitz): the "conditional" condition is always true.
+// We should only do this if the user has the hg codereview extension
+// enabled and verifies that the go.tools subrepo is checked out with
+// a suitably recently version. In prep for the cmd/api rewrite.
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/exec"
+	"os/user"
+	"path/filepath"
+	"strings"
+)
+
+// goToolsVersion is the hg revision of the go.tools subrepo we need
+// to build cmd/api.  This only needs to be updated whenever a go/types
+// bug fix is needed by the cmd/api tool.
+const goToolsVersion = "6698ca2900e2"
+
+var goroot string
+
+func main() {
+	log.SetFlags(0)
+	goroot = os.Getenv("GOROOT") // should be set by run.{bash,bat}
+	if goroot == "" {
+		log.Fatal("No $GOROOT set.")
+	}
+	_, err := exec.LookPath("hg")
+	if err != nil {
+		fmt.Println("Skipping cmd/api checks; hg not available")
+		return
+	}
+
+	gopath := prepGoPath()
+
+	cmd := exec.Command("go", "install", "--tags=api_tool", "cmd/api")
+	cmd.Env = append([]string{"GOPATH=" + gopath}, filterOut(os.Environ(), "GOARCH")...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Fatalf("Error installing cmd/api: %v\n%s", err, out)
+	}
+
+	out, err = exec.Command("go", "tool", "api",
+		"-c", file("go1", "go1.1", "go1.2"),
+		"-next", file("next"),
+		"-except", file("except")).CombinedOutput()
+	if err != nil {
+		log.Fatalf("Error running API checker: %v\n%s", err, out)
+	}
+	fmt.Print(string(out))
+}
+
+// filterOut returns a copy of the src environment without environment
+// variables from remove.
+// TODO: delete when issue 6201 is fixed.
+func filterOut(src []string, remove ...string) (out []string) {
+S:
+	for _, s := range src {
+		for _, r := range remove {
+			if strings.HasPrefix(s, r) && strings.HasPrefix(s, r+"=") {
+				continue S
+			}
+		}
+		out = append(out, s)
+	}
+	return
+}
+
+// file expands s to $GOROOT/api/s.txt.
+// If there are more than 1, they're comma-separated.
+func file(s ...string) string {
+	if len(s) > 1 {
+		return file(s[0]) + "," + file(s[1:]...)
+	}
+	return filepath.Join(goroot, "api", s[0]+".txt")
+}
+
+// prepGoPath returns a GOPATH for the "go" tool to compile the API tool with.
+// It tries to re-use a go.tools checkout from a previous run if possible,
+// else it hg clones it.
+func prepGoPath() string {
+	const tempBase = "go.tools.TMP"
+
+	username := ""
+	u, err := user.Current()
+	if err == nil {
+		username = u.Username
+	} else {
+		// Only need to handle Unix here, as Windows's os/user uses
+		// native syscall and should work fine without cgo.
+		username = os.Getenv("USER")
+		if username == "" {
+			log.Fatalf("Error getting current user: %v", err)
+		}
+	}
+
+	// The GOPATH we'll return
+	gopath := filepath.Join(os.TempDir(), "gopath-api-"+cleanUsername(username), goToolsVersion)
+
+	// cloneDir is where we run "hg clone".
+	cloneDir := filepath.Join(gopath, "src", "code.google.com", "p")
+
+	// The dir we clone into. We only atomically rename it to finalDir on
+	// clone success.
+	tmpDir := filepath.Join(cloneDir, tempBase)
+
+	// finalDir is where the checkout will live once it's complete.
+	finalDir := filepath.Join(cloneDir, "go.tools")
+
+	if goToolsCheckoutGood(finalDir) {
+		return gopath
+	}
+	os.RemoveAll(finalDir) // in case it's there but corrupt
+	os.RemoveAll(tmpDir)   // in case of aborted hg clone before
+
+	if err := os.MkdirAll(cloneDir, 0700); err != nil {
+		log.Fatal(err)
+	}
+	cmd := exec.Command("hg",
+		"clone", "--rev="+goToolsVersion,
+		"https://code.google.com/p/go.tools",
+		tempBase)
+	cmd.Dir = cloneDir
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		if _, err := http.Head("http://ip.appspot.com/"); err != nil {
+			log.Printf("# Skipping API check; network appears to be unavailable")
+			os.Exit(0)
+		}
+		log.Fatalf("Error running hg clone on go.tools: %v\n%s", err, out)
+	}
+	if err := os.Rename(tmpDir, finalDir); err != nil {
+		log.Fatal(err)
+	}
+	return gopath
+}
+
+func cleanUsername(n string) string {
+	b := make([]rune, len(n))
+	for i, r := range n {
+		if r == '\\' || r == '/' || r == ':' {
+			b[i] = '_'
+		} else {
+			b[i] = r
+		}
+	}
+	return string(b)
+}
+
+func goToolsCheckoutGood(dir string) bool {
+	if _, err := os.Stat(dir); err != nil {
+		return false
+	}
+
+	cmd := exec.Command("hg", "id", "--id")
+	cmd.Dir = dir
+	out, err := cmd.Output()
+	if err != nil {
+		return false
+	}
+	id := strings.TrimSpace(string(out))
+	if id != goToolsVersion {
+		return false
+	}
+
+	cmd = exec.Command("hg", "status")
+	cmd.Dir = dir
+	out, err = cmd.Output()
+	if err != nil || len(out) > 0 {
+		return false
+	}
+
+	return true
+}