libgo: update to go1.7rc3

    
    Reviewed-on: https://go-review.googlesource.com/25150

From-SVN: r238662

1 files changed, 56 insertions, 42 deletions

diff --git a/libgo/go/net/lookup.go b/libgo/go/net/lookup.go
index 7aa111ba929..c169e9e902c 100644
--- a/libgo/go/net/lookup.go
+++ b/libgo/go/net/lookup.go
@@ -1,12 +1,13 @@
-// Copyright 2012 The Go Authors.  All rights reserved.
+// 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 net
 
 import (
+	"context"
+	"internal/nettrace"
 	"internal/singleflight"
-	"time"
 )
 
 // protocols contains minimal mappings between internet protocol
@@ -33,7 +34,7 @@ func LookupHost(host string) (addrs []string, err error) {
 	if ip := ParseIP(host); ip != nil {
 		return []string{host}, nil
 	}
-	return lookupHost(host)
+	return lookupHost(context.Background(), host)
 }
 
 // LookupIP looks up host using the local resolver.
@@ -47,7 +48,7 @@ func LookupIP(host string) (ips []IP, err error) {
 	if ip := ParseIP(host); ip != nil {
 		return []IP{ip}, nil
 	}
-	addrs, err := lookupIPMerge(host)
+	addrs, err := lookupIPMerge(context.Background(), host)
 	if err != nil {
 		return
 	}
@@ -63,9 +64,9 @@ var lookupGroup singleflight.Group
 // lookupIPMerge wraps lookupIP, but makes sure that for any given
 // host, only one lookup is in-flight at a time. The returned memory
 // is always owned by the caller.
-func lookupIPMerge(host string) (addrs []IPAddr, err error) {
+func lookupIPMerge(ctx context.Context, host string) (addrs []IPAddr, err error) {
 	addrsi, err, shared := lookupGroup.Do(host, func() (interface{}, error) {
-		return testHookLookupIP(lookupIP, host)
+		return testHookLookupIP(ctx, lookupIP, host)
 	})
 	return lookupIPReturn(addrsi, err, shared)
 }
@@ -85,52 +86,65 @@ func lookupIPReturn(addrsi interface{}, err error, shared bool) ([]IPAddr, error
 	return addrs, nil
 }
 
-// lookupIPDeadline looks up a hostname with a deadline.
-func lookupIPDeadline(host string, deadline time.Time) (addrs []IPAddr, err error) {
-	if deadline.IsZero() {
-		return lookupIPMerge(host)
+// ipAddrsEface returns an empty interface slice of addrs.
+func ipAddrsEface(addrs []IPAddr) []interface{} {
+	s := make([]interface{}, len(addrs))
+	for i, v := range addrs {
+		s[i] = v
 	}
+	return s
+}
 
-	// We could push the deadline down into the name resolution
-	// functions.  However, the most commonly used implementation
-	// calls getaddrinfo, which has no timeout.
-
-	timeout := deadline.Sub(time.Now())
-	if timeout <= 0 {
-		return nil, errTimeout
+// lookupIPContext looks up a hostname with a context.
+//
+// TODO(bradfitz): rename this function. All the other
+// build-tag-specific lookupIP funcs also take a context now, so this
+// name is no longer great. Maybe make this lookupIPMerge and ditch
+// the other one, making its callers call this instead with a
+// context.Background().
+func lookupIPContext(ctx context.Context, host string) (addrs []IPAddr, err error) {
+	trace, _ := ctx.Value(nettrace.TraceKey{}).(*nettrace.Trace)
+	if trace != nil && trace.DNSStart != nil {
+		trace.DNSStart(host)
+	}
+	// The underlying resolver func is lookupIP by default but it
+	// can be overridden by tests. This is needed by net/http, so it
+	// uses a context key instead of unexported variables.
+	resolverFunc := lookupIP
+	if alt, _ := ctx.Value(nettrace.LookupIPAltResolverKey{}).(func(context.Context, string) ([]IPAddr, error)); alt != nil {
+		resolverFunc = alt
 	}
-	t := time.NewTimer(timeout)
-	defer t.Stop()
 
 	ch := lookupGroup.DoChan(host, func() (interface{}, error) {
-		return testHookLookupIP(lookupIP, host)
+		return testHookLookupIP(ctx, resolverFunc, host)
 	})
 
 	select {
-	case <-t.C:
-		// The DNS lookup timed out for some reason.  Force
+	case <-ctx.Done():
+		// The DNS lookup timed out for some reason. Force
 		// future requests to start the DNS lookup again
 		// rather than waiting for the current lookup to
-		// complete.  See issue 8602.
+		// complete. See issue 8602.
+		err := mapErr(ctx.Err())
 		lookupGroup.Forget(host)
-
-		return nil, errTimeout
-
+		if trace != nil && trace.DNSDone != nil {
+			trace.DNSDone(nil, false, err)
+		}
+		return nil, err
 	case r := <-ch:
+		if trace != nil && trace.DNSDone != nil {
+			addrs, _ := r.Val.([]IPAddr)
+			trace.DNSDone(ipAddrsEface(addrs), r.Shared, r.Err)
+		}
 		return lookupIPReturn(r.Val, r.Err, r.Shared)
 	}
 }
 
 // LookupPort looks up the port for the given network and service.
 func LookupPort(network, service string) (port int, err error) {
-	if service == "" {
-		// Lock in the legacy behavior that an empty string
-		// means port 0. See Issue 13610.
-		return 0, nil
-	}
-	port, _, ok := dtoi(service, 0)
-	if !ok && port != big && port != -big {
-		port, err = lookupPort(network, service)
+	port, needsLookup := parsePort(service)
+	if needsLookup {
+		port, err = lookupPort(context.Background(), network, service)
 		if err != nil {
 			return 0, err
 		}
@@ -146,39 +160,39 @@ func LookupPort(network, service string) (port int, err error) {
 // LookupHost or LookupIP directly; both take care of resolving
 // the canonical name as part of the lookup.
 func LookupCNAME(name string) (cname string, err error) {
-	return lookupCNAME(name)
+	return lookupCNAME(context.Background(), name)
 }
 
 // LookupSRV tries to resolve an SRV query of the given service,
-// protocol, and domain name.  The proto is "tcp" or "udp".
+// protocol, and domain name. The proto is "tcp" or "udp".
 // The returned records are sorted by priority and randomized
 // by weight within a priority.
 //
 // LookupSRV constructs the DNS name to look up following RFC 2782.
-// That is, it looks up _service._proto.name.  To accommodate services
+// That is, it looks up _service._proto.name. To accommodate services
 // publishing SRV records under non-standard names, if both service
 // and proto are empty strings, LookupSRV looks up name directly.
 func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) {
-	return lookupSRV(service, proto, name)
+	return lookupSRV(context.Background(), service, proto, name)
 }
 
 // LookupMX returns the DNS MX records for the given domain name sorted by preference.
 func LookupMX(name string) (mxs []*MX, err error) {
-	return lookupMX(name)
+	return lookupMX(context.Background(), name)
 }
 
 // LookupNS returns the DNS NS records for the given domain name.
 func LookupNS(name string) (nss []*NS, err error) {
-	return lookupNS(name)
+	return lookupNS(context.Background(), name)
 }
 
 // LookupTXT returns the DNS TXT records for the given domain name.
 func LookupTXT(name string) (txts []string, err error) {
-	return lookupTXT(name)
+	return lookupTXT(context.Background(), name)
 }
 
 // LookupAddr performs a reverse lookup for the given address, returning a list
 // of names mapping to that address.
 func LookupAddr(addr string) (names []string, err error) {
-	return lookupAddr(addr)
+	return lookupAddr(context.Background(), addr)
 }