libgo: Update to weekly.2012-02-14 release.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@184798 138bc75d-0d04-0410-961f-82ee72b054a4

14 files changed, 474 insertions, 152 deletions

diff --git a/libgo/go/net/http/cgi/host_test.go b/libgo/go/net/http/cgi/host_test.go
index b8dbdb4edd2..fec35b72f99 100644
--- a/libgo/go/net/http/cgi/host_test.go
+++ b/libgo/go/net/http/cgi/host_test.go
@@ -19,6 +19,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -355,7 +356,7 @@ func TestCopyError(t *testing.T) {
 		if err != nil {
 			return false
 		}
-		return p.Signal(os.UnixSignal(0)) == nil
+		return p.Signal(syscall.Signal(0)) == nil
 	}
 
 	if !childRunning() {
diff --git a/libgo/go/net/http/doc.go b/libgo/go/net/http/doc.go
index 8962ed31e6a..b6ae8b87a2f 100644
--- a/libgo/go/net/http/doc.go
+++ b/libgo/go/net/http/doc.go
@@ -12,7 +12,7 @@ Get, Head, Post, and PostForm make HTTP requests:
 	resp, err := http.Post("http://example.com/upload", "image/jpeg", &buf)
 	...
 	resp, err := http.PostForm("http://example.com/form",
- 		url.Values{"key": {"Value"}, "id": {"123"}})
+		url.Values{"key": {"Value"}, "id": {"123"}})
 
 The client must close the response body when finished with it:
 
@@ -60,7 +60,7 @@ Handle and HandleFunc add handlers to DefaultServeMux:
 	http.Handle("/foo", fooHandler)
 
 	http.HandleFunc("/bar", func(w http.ResponseWriter, r *http.Request) {
-		fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.RawPath))
+		fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
 	})
 
 	log.Fatal(http.ListenAndServe(":8080", nil))
diff --git a/libgo/go/net/http/fcgi/child.go b/libgo/go/net/http/fcgi/child.go
index c94b9a7b249..c8b9a33c87b 100644
--- a/libgo/go/net/http/fcgi/child.go
+++ b/libgo/go/net/http/fcgi/child.go
@@ -243,9 +243,9 @@ func (c *child) serveRequest(req *request, body io.ReadCloser) {
 }
 
 // Serve accepts incoming FastCGI connections on the listener l, creating a new
-// service thread for each. The service threads read requests and then call handler
+// goroutine for each. The goroutine reads requests and then calls handler
 // to reply to them.
-// If l is nil, Serve accepts connections on stdin.
+// If l is nil, Serve accepts connections from os.Stdin.
 // If handler is nil, http.DefaultServeMux is used.
 func Serve(l net.Listener, handler http.Handler) error {
 	if l == nil {
diff --git a/libgo/go/net/http/fs.go b/libgo/go/net/http/fs.go
index 1392ca68ad6..f35dd32c305 100644
--- a/libgo/go/net/http/fs.go
+++ b/libgo/go/net/http/fs.go
@@ -17,7 +17,6 @@ import (
 	"strconv"
 	"strings"
 	"time"
-	"unicode/utf8"
 )
 
 // A Dir implements http.FileSystem using the native file
@@ -58,32 +57,6 @@ type File interface {
 	Seek(offset int64, whence int) (int64, error)
 }
 
-// Heuristic: b is text if it is valid UTF-8 and doesn't
-// contain any unprintable ASCII or Unicode characters.
-func isText(b []byte) bool {
-	for len(b) > 0 && utf8.FullRune(b) {
-		rune, size := utf8.DecodeRune(b)
-		if size == 1 && rune == utf8.RuneError {
-			// decoding error
-			return false
-		}
-		if 0x7F <= rune && rune <= 0x9F {
-			return false
-		}
-		if rune < ' ' {
-			switch rune {
-			case '\n', '\r', '\t':
-				// okay
-			default:
-				// binary garbage
-				return false
-			}
-		}
-		b = b[size:]
-	}
-	return true
-}
-
 func dirList(w ResponseWriter, f File) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	fmt.Fprintf(w, "<pre>\n")
@@ -104,6 +77,126 @@ func dirList(w ResponseWriter, f File) {
 	fmt.Fprintf(w, "</pre>\n")
 }
 
+// ServeContent replies to the request using the content in the
+// provided ReadSeeker.  The main benefit of ServeContent over io.Copy
+// is that it handles Range requests properly, sets the MIME type, and
+// handles If-Modified-Since requests.
+//
+// If the response's Content-Type header is not set, ServeContent
+// first tries to deduce the type from name's file extension and,
+// if that fails, falls back to reading the first block of the content
+// and passing it to DetectContentType.
+// The name is otherwise unused; in particular it can be empty and is
+// never sent in the response.
+//
+// If modtime is not the zero time, ServeContent includes it in a
+// Last-Modified header in the response.  If the request includes an
+// If-Modified-Since header, ServeContent uses modtime to decide
+// whether the content needs to be sent at all.
+//
+// The content's Seek method must work: ServeContent uses
+// a seek to the end of the content to determine its size.
+//
+// Note that *os.File implements the io.ReadSeeker interface.
+func ServeContent(w ResponseWriter, req *Request, name string, modtime time.Time, content io.ReadSeeker) {
+	size, err := content.Seek(0, os.SEEK_END)
+	if err != nil {
+		Error(w, "seeker can't seek", StatusInternalServerError)
+		return
+	}
+	_, err = content.Seek(0, os.SEEK_SET)
+	if err != nil {
+		Error(w, "seeker can't seek", StatusInternalServerError)
+		return
+	}
+	serveContent(w, req, name, modtime, size, content)
+}
+
+// if name is empty, filename is unknown. (used for mime type, before sniffing)
+// if modtime.IsZero(), modtime is unknown.
+// content must be seeked to the beginning of the file.
+func serveContent(w ResponseWriter, r *Request, name string, modtime time.Time, size int64, content io.ReadSeeker) {
+	if checkLastModified(w, r, modtime) {
+		return
+	}
+
+	code := StatusOK
+
+	// If Content-Type isn't set, use the file's extension to find it.
+	if w.Header().Get("Content-Type") == "" {
+		ctype := mime.TypeByExtension(filepath.Ext(name))
+		if ctype == "" {
+			// read a chunk to decide between utf-8 text and binary
+			var buf [1024]byte
+			n, _ := io.ReadFull(content, buf[:])
+			b := buf[:n]
+			ctype = DetectContentType(b)
+			_, err := content.Seek(0, os.SEEK_SET) // rewind to output whole file
+			if err != nil {
+				Error(w, "seeker can't seek", StatusInternalServerError)
+				return
+			}
+		}
+		w.Header().Set("Content-Type", ctype)
+	}
+
+	// handle Content-Range header.
+	// TODO(adg): handle multiple ranges
+	sendSize := size
+	if size >= 0 {
+		ranges, err := parseRange(r.Header.Get("Range"), size)
+		if err == nil && len(ranges) > 1 {
+			err = errors.New("multiple ranges not supported")
+		}
+		if err != nil {
+			Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
+			return
+		}
+		if len(ranges) == 1 {
+			ra := ranges[0]
+			if _, err := content.Seek(ra.start, os.SEEK_SET); err != nil {
+				Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
+				return
+			}
+			sendSize = ra.length
+			code = StatusPartialContent
+			w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", ra.start, ra.start+ra.length-1, size))
+		}
+
+		w.Header().Set("Accept-Ranges", "bytes")
+		if w.Header().Get("Content-Encoding") == "" {
+			w.Header().Set("Content-Length", strconv.FormatInt(sendSize, 10))
+		}
+	}
+
+	w.WriteHeader(code)
+
+	if r.Method != "HEAD" {
+		if sendSize == -1 {
+			io.Copy(w, content)
+		} else {
+			io.CopyN(w, content, sendSize)
+		}
+	}
+}
+
+// modtime is the modification time of the resource to be served, or IsZero().
+// return value is whether this request is now complete.
+func checkLastModified(w ResponseWriter, r *Request, modtime time.Time) bool {
+	if modtime.IsZero() {
+		return false
+	}
+
+	// The Date-Modified header truncates sub-second precision, so
+	// use mtime < t+1s instead of mtime <= t to check for unmodified.
+	if t, err := time.Parse(TimeFormat, r.Header.Get("If-Modified-Since")); err == nil && modtime.Before(t.Add(1*time.Second)) {
+		w.WriteHeader(StatusNotModified)
+		return true
+	}
+	w.Header().Set("Last-Modified", modtime.UTC().Format(TimeFormat))
+	return false
+}
+
 // name is '/'-separated, not filepath.Separator.
 func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirect bool) {
 	const indexPage = "/index.html"
@@ -148,14 +241,11 @@ func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirec
 		}
 	}
 
-	if t, err := time.Parse(TimeFormat, r.Header.Get("If-Modified-Since")); err == nil && !d.ModTime().After(t) {
-		w.WriteHeader(StatusNotModified)
-		return
-	}
-	w.Header().Set("Last-Modified", d.ModTime().UTC().Format(TimeFormat))
-
 	// use contents of index.html for directory, if present
 	if d.IsDir() {
+		if checkLastModified(w, r, d.ModTime()) {
+			return
+		}
 		index := name + indexPage
 		ff, err := fs.Open(index)
 		if err == nil {
@@ -174,60 +264,7 @@ func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirec
 		return
 	}
 
-	// serve file
-	size := d.Size()
-	code := StatusOK
-
-	// If Content-Type isn't set, use the file's extension to find it.
-	if w.Header().Get("Content-Type") == "" {
-		ctype := mime.TypeByExtension(filepath.Ext(name))
-		if ctype == "" {
-			// read a chunk to decide between utf-8 text and binary
-			var buf [1024]byte
-			n, _ := io.ReadFull(f, buf[:])
-			b := buf[:n]
-			if isText(b) {
-				ctype = "text/plain; charset=utf-8"
-			} else {
-				// generic binary
-				ctype = "application/octet-stream"
-			}
-			f.Seek(0, os.SEEK_SET) // rewind to output whole file
-		}
-		w.Header().Set("Content-Type", ctype)
-	}
-
-	// handle Content-Range header.
-	// TODO(adg): handle multiple ranges
-	ranges, err := parseRange(r.Header.Get("Range"), size)
-	if err == nil && len(ranges) > 1 {
-		err = errors.New("multiple ranges not supported")
-	}
-	if err != nil {
-		Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
-		return
-	}
-	if len(ranges) == 1 {
-		ra := ranges[0]
-		if _, err := f.Seek(ra.start, os.SEEK_SET); err != nil {
-			Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
-			return
-		}
-		size = ra.length
-		code = StatusPartialContent
-		w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", ra.start, ra.start+ra.length-1, d.Size()))
-	}
-
-	w.Header().Set("Accept-Ranges", "bytes")
-	if w.Header().Get("Content-Encoding") == "" {
-		w.Header().Set("Content-Length", strconv.FormatInt(size, 10))
-	}
-
-	w.WriteHeader(code)
-
-	if r.Method != "HEAD" {
-		io.CopyN(w, f, size)
-	}
+	serveContent(w, r, d.Name(), d.ModTime(), d.Size(), f)
 }
 
 // localRedirect gives a Moved Permanently response.
diff --git a/libgo/go/net/http/fs_test.go b/libgo/go/net/http/fs_test.go
index feea9209e6a..143617e95fc 100644
--- a/libgo/go/net/http/fs_test.go
+++ b/libgo/go/net/http/fs_test.go
@@ -5,15 +5,22 @@
 package http_test
 
 import (
+	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
+	"net"
 	. "net/http"
 	"net/http/httptest"
 	"net/url"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"regexp"
+	"runtime"
 	"strings"
 	"testing"
+	"time"
 )
 
 const (
@@ -56,18 +63,18 @@ func TestServeFile(t *testing.T) {
 	req.Method = "GET"
 
 	// straight GET
-	_, body := getBody(t, req)
+	_, body := getBody(t, "straight get", req)
 	if !equal(body, file) {
 		t.Fatalf("body mismatch: got %q, want %q", body, file)
 	}
 
 	// Range tests
-	for _, rt := range ServeFileRangeTests {
+	for i, rt := range ServeFileRangeTests {
 		req.Header.Set("Range", "bytes="+rt.r)
 		if rt.r == "" {
 			req.Header["Range"] = nil
 		}
-		r, body := getBody(t, req)
+		r, body := getBody(t, fmt.Sprintf("test %d", i), req)
 		if r.StatusCode != rt.code {
 			t.Errorf("range=%q: StatusCode=%d, want %d", rt.r, r.StatusCode, rt.code)
 		}
@@ -298,7 +305,6 @@ func TestServeIndexHtml(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		defer res.Body.Close()
 		b, err := ioutil.ReadAll(res.Body)
 		if err != nil {
 			t.Fatal("reading Body:", err)
@@ -306,21 +312,146 @@ func TestServeIndexHtml(t *testing.T) {
 		if s := string(b); s != want {
 			t.Errorf("for path %q got %q, want %q", path, s, want)
 		}
+		res.Body.Close()
+	}
+}
+
+func TestServeContent(t *testing.T) {
+	type req struct {
+		name    string
+		modtime time.Time
+		content io.ReadSeeker
+	}
+	ch := make(chan req, 1)
+	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		p := <-ch
+		ServeContent(w, r, p.name, p.modtime, p.content)
+	}))
+	defer ts.Close()
+
+	css, err := os.Open("testdata/style.css")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer css.Close()
+
+	ch <- req{"style.css", time.Time{}, css}
+	res, err := Get(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if g, e := res.Header.Get("Content-Type"), "text/css; charset=utf-8"; g != e {
+		t.Errorf("style.css: content type = %q, want %q", g, e)
+	}
+	if g := res.Header.Get("Last-Modified"); g != "" {
+		t.Errorf("want empty Last-Modified; got %q", g)
+	}
+
+	fi, err := css.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	ch <- req{"style.html", fi.ModTime(), css}
+	res, err = Get(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if g, e := res.Header.Get("Content-Type"), "text/html; charset=utf-8"; g != e {
+		t.Errorf("style.html: content type = %q, want %q", g, e)
+	}
+	if g := res.Header.Get("Last-Modified"); g == "" {
+		t.Errorf("want non-empty last-modified")
 	}
 }
 
-func getBody(t *testing.T, req Request) (*Response, []byte) {
+// verifies that sendfile is being used on Linux
+func TestLinuxSendfile(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Logf("skipping; linux-only test")
+		return
+	}
+	_, err := exec.LookPath("strace")
+	if err != nil {
+		t.Logf("skipping; strace not found in path")
+		return
+	}
+
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	lnf, err := ln.(*net.TCPListener).File()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln.Close()
+
+	var buf bytes.Buffer
+	child := exec.Command("strace", "-f", os.Args[0], "-test.run=TestLinuxSendfileChild")
+	child.ExtraFiles = append(child.ExtraFiles, lnf)
+	child.Env = append([]string{"GO_WANT_HELPER_PROCESS=1"}, os.Environ()...)
+	child.Stdout = &buf
+	child.Stderr = &buf
+	err = child.Start()
+	if err != nil {
+		t.Logf("skipping; failed to start straced child: %v", err)
+		return
+	}
+
+	_, err = Get(fmt.Sprintf("http://%s/", ln.Addr()))
+	if err != nil {
+		t.Errorf("http client error: %v", err)
+		return
+	}
+
+	// Force child to exit cleanly.
+	Get(fmt.Sprintf("http://%s/quit", ln.Addr()))
+	child.Wait()
+
+	rx := regexp.MustCompile(`sendfile(64)?\(\d+,\s*\d+,\s*NULL,\s*\d+\)\s*=\s*\d+\s*\n`)
+	rxResume := regexp.MustCompile(`<\.\.\. sendfile(64)? resumed> \)\s*=\s*\d+\s*\n`)
+	out := buf.String()
+	if !rx.MatchString(out) && !rxResume.MatchString(out) {
+		t.Errorf("no sendfile system call found in:\n%s", out)
+	}
+}
+
+func getBody(t *testing.T, testName string, req Request) (*Response, []byte) {
 	r, err := DefaultClient.Do(&req)
 	if err != nil {
-		t.Fatal(req.URL.String(), "send:", err)
+		t.Fatalf("%s: for URL %q, send error: %v", testName, req.URL.String(), err)
 	}
 	b, err := ioutil.ReadAll(r.Body)
 	if err != nil {
-		t.Fatal("reading Body:", err)
+		t.Fatalf("%s: for URL %q, reading body: %v", testName, req.URL.String(), err)
 	}
 	return r, b
 }
 
+// TestLinuxSendfileChild isn't a real test. It's used as a helper process
+// for TestLinuxSendfile.
+func TestLinuxSendfileChild(*testing.T) {
+	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
+		return
+	}
+	defer os.Exit(0)
+	fd3 := os.NewFile(3, "ephemeral-port-listener")
+	ln, err := net.FileListener(fd3)
+	if err != nil {
+		panic(err)
+	}
+	mux := NewServeMux()
+	mux.Handle("/", FileServer(Dir("testdata")))
+	mux.HandleFunc("/quit", func(ResponseWriter, *Request) {
+		os.Exit(0)
+	})
+	s := &Server{Handler: mux}
+	err = s.Serve(ln)
+	if err != nil {
+		panic(err)
+	}
+}
+
 func equal(a, b []byte) bool {
 	if len(a) != len(b) {
 		return false
diff --git a/libgo/go/net/http/httptest/server.go b/libgo/go/net/http/httptest/server.go
index 5b02e143d4a..8d911f7575b 100644
--- a/libgo/go/net/http/httptest/server.go
+++ b/libgo/go/net/http/httptest/server.go
@@ -61,7 +61,7 @@ func newLocalListener() net.Listener {
 
 // When debugging a particular http server-based test,
 // this flag lets you run
-//	gotest -run=BrokenTest -httptest.serve=127.0.0.1:8000
+//	go test -run=BrokenTest -httptest.serve=127.0.0.1:8000
 // to start the broken server so you can interact with it manually.
 var serve = flag.String("httptest.serve", "", "if non-empty, httptest.NewServer serves on this address and blocks")
 
@@ -95,7 +95,7 @@ func (s *Server) Start() {
 	s.URL = "http://" + s.Listener.Addr().String()
 	go s.Config.Serve(s.Listener)
 	if *serve != "" {
-		fmt.Println(os.Stderr, "httptest: serving on", s.URL)
+		fmt.Fprintln(os.Stderr, "httptest: serving on", s.URL)
 		select {}
 	}
 }
diff --git a/libgo/go/net/http/httptest/server_test.go b/libgo/go/net/http/httptest/server_test.go
new file mode 100644
index 00000000000..500a9f0b800
--- /dev/null
+++ b/libgo/go/net/http/httptest/server_test.go
@@ -0,0 +1,29 @@
+// 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 httptest
+
+import (
+	"io/ioutil"
+	"net/http"
+	"testing"
+)
+
+func TestServer(t *testing.T) {
+	ts := NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("hello"))
+	}))
+	defer ts.Close()
+	res, err := http.Get(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(got) != "hello" {
+		t.Errorf("got %q, want hello", string(got))
+	}
+}
diff --git a/libgo/go/net/http/pprof/pprof.go b/libgo/go/net/http/pprof/pprof.go
index 21eac4743ac..0fe41b7d31b 100644
--- a/libgo/go/net/http/pprof/pprof.go
+++ b/libgo/go/net/http/pprof/pprof.go
@@ -12,15 +12,23 @@
 // The handled paths all begin with /debug/pprof/.
 //
 // To use pprof, link this package into your program:
-//	import _ "http/pprof"
+//	import _ "net/http/pprof"
 //
 // Then use the pprof tool to look at the heap profile:
 //
-//	pprof http://localhost:6060/debug/pprof/heap
+//	go tool pprof http://localhost:6060/debug/pprof/heap
 //
 // Or to look at a 30-second CPU profile:
 //
-//	pprof http://localhost:6060/debug/pprof/profile
+//	go tool pprof http://localhost:6060/debug/pprof/profile
+//
+// Or to look at the thread creation profile:
+//
+//	go tool pprof http://localhost:6060/debug/pprof/thread
+//
+// For a study of the facility in action, visit
+//
+//	http://blog.golang.org/2011/06/profiling-go-programs.html
 //
 package pprof
 
@@ -43,6 +51,7 @@ func init() {
 	http.Handle("/debug/pprof/profile", http.HandlerFunc(Profile))
 	http.Handle("/debug/pprof/heap", http.HandlerFunc(Heap))
 	http.Handle("/debug/pprof/symbol", http.HandlerFunc(Symbol))
+	http.Handle("/debug/pprof/thread", http.HandlerFunc(Thread))
 }
 
 // Cmdline responds with the running program's
@@ -60,6 +69,13 @@ func Heap(w http.ResponseWriter, r *http.Request) {
 	pprof.WriteHeapProfile(w)
 }
 
+// Thread responds with the pprof-formatted thread creation profile.
+// The package initialization registers it as /debug/pprof/thread.
+func Thread(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	pprof.WriteThreadProfile(w)
+}
+
 // Profile responds with the pprof-formatted cpu profile.
 // The package initialization registers it as /debug/pprof/profile.
 func Profile(w http.ResponseWriter, r *http.Request) {
diff --git a/libgo/go/net/http/response_test.go b/libgo/go/net/http/response_test.go
index e5d01698e55..165ec3624a4 100644
--- a/libgo/go/net/http/response_test.go
+++ b/libgo/go/net/http/response_test.go
@@ -321,9 +321,7 @@ func TestReadResponseCloseInMiddle(t *testing.T) {
 		}
 		if test.compressed {
 			buf.WriteString("Content-Encoding: gzip\r\n")
-			var err error
-			wr, err = gzip.NewWriter(wr)
-			checkErr(err, "gzip.NewWriter")
+			wr = gzip.NewWriter(wr)
 		}
 		buf.WriteString("\r\n")
 
@@ -337,7 +335,7 @@ func TestReadResponseCloseInMiddle(t *testing.T) {
 			wr.Write(chunk)
 		}
 		if test.compressed {
-			err := wr.(*gzip.Compressor).Close()
+			err := wr.(*gzip.Writer).Close()
 			checkErr(err, "compressor close")
 		}
 		if test.chunked {
diff --git a/libgo/go/net/http/server.go b/libgo/go/net/http/server.go
index 288539ba576..e715c73cb6e 100644
--- a/libgo/go/net/http/server.go
+++ b/libgo/go/net/http/server.go
@@ -59,7 +59,9 @@ type ResponseWriter interface {
 
 	// Write writes the data to the connection as part of an HTTP reply.
 	// If WriteHeader has not yet been called, Write calls WriteHeader(http.StatusOK)
-	// before writing the data.
+	// before writing the data.  If the Header does not contain a
+	// Content-Type line, Write adds a Content-Type set to the result of passing
+	// the initial 512 bytes of written data to DetectContentType.
 	Write([]byte) (int, error)
 
 	// WriteHeader sends an HTTP response header with status code.
@@ -833,11 +835,17 @@ func RedirectHandler(url string, code int) Handler {
 // redirecting any request containing . or .. elements to an
 // equivalent .- and ..-free URL.
 type ServeMux struct {
-	m map[string]Handler
+	mu sync.RWMutex
+	m  map[string]muxEntry
+}
+
+type muxEntry struct {
+	explicit bool
+	h        Handler
 }
 
 // NewServeMux allocates and returns a new ServeMux.
-func NewServeMux() *ServeMux { return &ServeMux{make(map[string]Handler)} }
+func NewServeMux() *ServeMux { return &ServeMux{m: make(map[string]muxEntry)} }
 
 // DefaultServeMux is the default ServeMux used by Serve.
 var DefaultServeMux = NewServeMux()
@@ -883,12 +891,28 @@ func (mux *ServeMux) match(path string) Handler {
 		}
 		if h == nil || len(k) > n {
 			n = len(k)
-			h = v
+			h = v.h
 		}
 	}
 	return h
 }
 
+// handler returns the handler to use for the request r.
+func (mux *ServeMux) handler(r *Request) Handler {
+	mux.mu.RLock()
+	defer mux.mu.RUnlock()
+
+	// Host-specific pattern takes precedence over generic ones
+	h := mux.match(r.Host + r.URL.Path)
+	if h == nil {
+		h = mux.match(r.URL.Path)
+	}
+	if h == nil {
+		h = NotFoundHandler()
+	}
+	return h
+}
+
 // ServeHTTP dispatches the request to the handler whose
 // pattern most closely matches the request URL.
 func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
@@ -898,30 +922,33 @@ func (mux *ServeMux) ServeHTTP(w ResponseWriter, r *Request) {
 		w.WriteHeader(StatusMovedPermanently)
 		return
 	}
-	// Host-specific pattern takes precedence over generic ones
-	h := mux.match(r.Host + r.URL.Path)
-	if h == nil {
-		h = mux.match(r.URL.Path)
-	}
-	if h == nil {
-		h = NotFoundHandler()
-	}
-	h.ServeHTTP(w, r)
+	mux.handler(r).ServeHTTP(w, r)
 }
 
 // Handle registers the handler for the given pattern.
+// If a handler already exists for pattern, Handle panics.
 func (mux *ServeMux) Handle(pattern string, handler Handler) {
+	mux.mu.Lock()
+	defer mux.mu.Unlock()
+
 	if pattern == "" {
 		panic("http: invalid pattern " + pattern)
 	}
+	if handler == nil {
+		panic("http: nil handler")
+	}
+	if mux.m[pattern].explicit {
+		panic("http: multiple registrations for " + pattern)
+	}
 
-	mux.m[pattern] = handler
+	mux.m[pattern] = muxEntry{explicit: true, h: handler}
 
 	// Helpful behavior:
-	// If pattern is /tree/, insert permanent redirect for /tree.
+	// If pattern is /tree/, insert an implicit permanent redirect for /tree.
+	// It can be overridden by an explicit registration.
 	n := len(pattern)
-	if n > 0 && pattern[n-1] == '/' {
-		mux.m[pattern[0:n-1]] = RedirectHandler(pattern, StatusMovedPermanently)
+	if n > 0 && pattern[n-1] == '/' && !mux.m[pattern[0:n-1]].explicit {
+		mux.m[pattern[0:n-1]] = muxEntry{h: RedirectHandler(pattern, StatusMovedPermanently)}
 	}
 }
 
@@ -980,15 +1007,26 @@ func (srv *Server) ListenAndServe() error {
 // then call srv.Handler to reply to them.
 func (srv *Server) Serve(l net.Listener) error {
 	defer l.Close()
+	var tempDelay time.Duration // how long to sleep on accept failure
 	for {
 		rw, e := l.Accept()
 		if e != nil {
 			if ne, ok := e.(net.Error); ok && ne.Temporary() {
-				log.Printf("http: Accept error: %v", e)
+				if tempDelay == 0 {
+					tempDelay = 5 * time.Millisecond
+				} else {
+					tempDelay *= 2
+				}
+				if max := 1 * time.Second; tempDelay > max {
+					tempDelay = max
+				}
+				log.Printf("http: Accept error: %v; retrying in %v", e, tempDelay)
+				time.Sleep(tempDelay)
 				continue
 			}
 			return e
 		}
+		tempDelay = 0
 		if srv.ReadTimeout != 0 {
 			rw.SetReadDeadline(time.Now().Add(srv.ReadTimeout))
 		}
diff --git a/libgo/go/net/http/sniff.go b/libgo/go/net/http/sniff.go
index c1c78e2417d..68f519b0542 100644
--- a/libgo/go/net/http/sniff.go
+++ b/libgo/go/net/http/sniff.go
@@ -9,15 +9,15 @@ import (
 	"encoding/binary"
 )
 
-// Content-type sniffing algorithm.
-// References in this file refer to this draft specification:
-//   http://mimesniff.spec.whatwg.org/
-
-// The algorithm prefers to use sniffLen bytes to make its decision.
+// The algorithm uses at most sniffLen bytes to make its decision.
 const sniffLen = 512
 
-// DetectContentType returns the sniffed Content-Type string
-// for the given data. This function always returns a valid MIME type.
+// DetectContentType implements the algorithm described
+// at http://mimesniff.spec.whatwg.org/ to determine the
+// Content-Type of the given data.  It considers at most the
+// first 512 bytes of data.  DetectContentType always returns
+// a valid MIME type: if it cannot determine a more specific one, it
+// returns "application/octet-stream".
 func DetectContentType(data []byte) string {
 	if len(data) > sniffLen {
 		data = data[:sniffLen]
diff --git a/libgo/go/net/http/transport.go b/libgo/go/net/http/transport.go
index 693215edd4f..3e48abafb5e 100644
--- a/libgo/go/net/http/transport.go
+++ b/libgo/go/net/http/transport.go
@@ -85,16 +85,16 @@ func ProxyFromEnvironment(req *Request) (*url.URL, error) {
 	if !useProxy(canonicalAddr(req.URL)) {
 		return nil, nil
 	}
-	proxyURL, err := url.ParseRequest(proxy)
+	proxyURL, err := url.Parse(proxy)
 	if err != nil {
-		return nil, errors.New("invalid proxy address")
-	}
-	if proxyURL.Host == "" {
-		proxyURL, err = url.ParseRequest("http://" + proxy)
-		if err != nil {
-			return nil, errors.New("invalid proxy address")
+		if u, err := url.Parse("http://" + proxy); err == nil {
+			proxyURL = u
+			err = nil
 		}
 	}
+	if err != nil {
+		return nil, fmt.Errorf("invalid proxy address %q: %v", proxy, err)
+	}
 	return proxyURL, nil
 }
 
@@ -235,15 +235,19 @@ func (cm *connectMethod) proxyAuth() string {
 	return ""
 }
 
-func (t *Transport) putIdleConn(pconn *persistConn) {
+// putIdleConn adds pconn to the list of idle persistent connections awaiting
+// a new request.
+// If pconn is no longer needed or not in a good state, putIdleConn
+// returns false.
+func (t *Transport) putIdleConn(pconn *persistConn) bool {
 	t.lk.Lock()
 	defer t.lk.Unlock()
 	if t.DisableKeepAlives || t.MaxIdleConnsPerHost < 0 {
 		pconn.close()
-		return
+		return false
 	}
 	if pconn.isBroken() {
-		return
+		return false
 	}
 	key := pconn.cacheKey
 	max := t.MaxIdleConnsPerHost
@@ -252,9 +256,10 @@ func (t *Transport) putIdleConn(pconn *persistConn) {
 	}
 	if len(t.idleConn[key]) >= max {
 		pconn.close()
-		return
+		return false
 	}
 	t.idleConn[key] = append(t.idleConn[key], pconn)
+	return true
 }
 
 func (t *Transport) getIdleConn(cm *connectMethod) (pconn *persistConn) {
@@ -565,7 +570,9 @@ func (pc *persistConn) readLoop() {
 				lastbody = resp.Body
 				waitForBodyRead = make(chan bool)
 				resp.Body.(*bodyEOFSignal).fn = func() {
-					pc.t.putIdleConn(pc)
+					if !pc.t.putIdleConn(pc) {
+						alive = false
+					}
 					waitForBodyRead <- true
 				}
 			} else {
@@ -578,7 +585,9 @@ func (pc *persistConn) readLoop() {
 				// read it (even though it'll just be 0, EOF).
 				lastbody = nil
 
-				pc.t.putIdleConn(pc)
+				if !pc.t.putIdleConn(pc) {
+					alive = false
+				}
 			}
 		}
 
diff --git a/libgo/go/net/http/transport_test.go b/libgo/go/net/http/transport_test.go
index caf81d6e46b..a36571a4446 100644
--- a/libgo/go/net/http/transport_test.go
+++ b/libgo/go/net/http/transport_test.go
@@ -16,6 +16,7 @@ import (
 	. "net/http"
 	"net/http/httptest"
 	"net/url"
+	"runtime"
 	"strconv"
 	"strings"
 	"testing"
@@ -441,11 +442,7 @@ func TestRoundTripGzip(t *testing.T) {
 		}
 		if accept == "gzip" {
 			rw.Header().Set("Content-Encoding", "gzip")
-			gz, err := gzip.NewWriter(rw)
-			if err != nil {
-				t.Errorf("gzip NewWriter: %v", err)
-				return
-			}
+			gz := gzip.NewWriter(rw)
 			gz.Write([]byte(responseBody))
 			gz.Close()
 		} else {
@@ -512,7 +509,7 @@ func TestTransportGzip(t *testing.T) {
 				rw.Header().Set("Content-Length", strconv.Itoa(buf.Len()))
 			}()
 		}
-		gz, _ := gzip.NewWriter(w)
+		gz := gzip.NewWriter(w)
 		gz.Write([]byte(testString))
 		if req.FormValue("body") == "large" {
 			io.CopyN(gz, rand.Reader, nRandBytes)
@@ -636,6 +633,70 @@ func TestTransportGzipRecursive(t *testing.T) {
 	}
 }
 
+// tests that persistent goroutine connections shut down when no longer desired.
+func TestTransportPersistConnLeak(t *testing.T) {
+	gotReqCh := make(chan bool)
+	unblockCh := make(chan bool)
+	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		gotReqCh <- true
+		<-unblockCh
+		w.Header().Set("Content-Length", "0")
+		w.WriteHeader(204)
+	}))
+	defer ts.Close()
+
+	tr := &Transport{}
+	c := &Client{Transport: tr}
+
+	n0 := runtime.Goroutines()
+
+	const numReq = 25
+	didReqCh := make(chan bool)
+	for i := 0; i < numReq; i++ {
+		go func() {
+			res, err := c.Get(ts.URL)
+			didReqCh <- true
+			if err != nil {
+				t.Errorf("client fetch error: %v", err)
+				return
+			}
+			res.Body.Close()
+		}()
+	}
+
+	// Wait for all goroutines to be stuck in the Handler.
+	for i := 0; i < numReq; i++ {
+		<-gotReqCh
+	}
+
+	nhigh := runtime.Goroutines()
+
+	// Tell all handlers to unblock and reply.
+	for i := 0; i < numReq; i++ {
+		unblockCh <- true
+	}
+
+	// Wait for all HTTP clients to be done.
+	for i := 0; i < numReq; i++ {
+		<-didReqCh
+	}
+
+	tr.CloseIdleConnections()
+	time.Sleep(100 * time.Millisecond)
+	runtime.GC()
+	runtime.GC() // even more.
+	nfinal := runtime.Goroutines()
+
+	growth := nfinal - n0
+
+	// We expect 0 or 1 extra goroutine, empirically.  Allow up to 5.
+	// Previously we were leaking one per numReq.
+	t.Logf("goroutine growth: %d -> %d -> %d (delta: %d)", n0, nhigh, nfinal, growth)
+	if int(growth) > 5 {
+		t.Error("too many new goroutines")
+	}
+}
+
 type fooProto struct{}
 
 func (fooProto) RoundTrip(req *Request) (*Response, error) {
diff --git a/libgo/go/net/http/triv.go b/libgo/go/net/http/triv.go
index 994fc0e32f6..c88a0fbce73 100644
--- a/libgo/go/net/http/triv.go
+++ b/libgo/go/net/http/triv.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build ignore
+
 package main
 
 import (