obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
should provide you with a source tree that is binary identical
to the one extracted from the above tarball.

if you have obtained the source via the command 'git clone',
however, do note that line-endings of files in your working
directory might differ from line-endings of the respective
files in the upstream repository.

1 files changed, 325 insertions, 0 deletions

diff --git a/libgo/go/netchan/common.go b/libgo/go/netchan/common.go
new file mode 100644
index 000000000..56c0b2519
--- /dev/null
+++ b/libgo/go/netchan/common.go
@@ -0,0 +1,325 @@
+// Copyright 2010 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 netchan
+
+import (
+	"gob"
+	"net"
+	"os"
+	"reflect"
+	"sync"
+	"time"
+)
+
+// The direction of a connection from the client's perspective.
+type Dir int
+
+const (
+	Recv Dir = iota
+	Send
+)
+
+func (dir Dir) String() string {
+	switch dir {
+	case Recv:
+		return "Recv"
+	case Send:
+		return "Send"
+	}
+	return "???"
+}
+
+// Payload types
+const (
+	payRequest = iota // request structure follows
+	payError          // error structure follows
+	payData           // user payload follows
+	payAck            // acknowledgement; no payload
+	payClosed         // channel is now closed
+	payAckSend        // payload has been delivered.
+)
+
+// A header is sent as a prefix to every transmission.  It will be followed by
+// a request structure, an error structure, or an arbitrary user payload structure.
+type header struct {
+	Id          int
+	PayloadType int
+	SeqNum      int64
+}
+
+// Sent with a header once per channel from importer to exporter to report
+// that it wants to bind to a channel with the specified direction for count
+// messages, with space for size buffered values. If count is -1, it means unlimited.
+type request struct {
+	Name  string
+	Count int64
+	Size  int
+	Dir   Dir
+}
+
+// Sent with a header to report an error.
+type error struct {
+	Error string
+}
+
+// Used to unify management of acknowledgements for import and export.
+type unackedCounter interface {
+	unackedCount() int64
+	ack() int64
+	seq() int64
+}
+
+// A channel and its direction.
+type chanDir struct {
+	ch  *reflect.ChanValue
+	dir Dir
+}
+
+// clientSet contains the objects and methods needed for tracking
+// clients of an exporter and draining outstanding messages.
+type clientSet struct {
+	mu      sync.Mutex // protects access to channel and client maps
+	names   map[string]*chanDir
+	clients map[unackedCounter]bool
+}
+
+// Mutex-protected encoder and decoder pair.
+type encDec struct {
+	decLock sync.Mutex
+	dec     *gob.Decoder
+	encLock sync.Mutex
+	enc     *gob.Encoder
+}
+
+func newEncDec(conn net.Conn) *encDec {
+	return &encDec{
+		dec: gob.NewDecoder(conn),
+		enc: gob.NewEncoder(conn),
+	}
+}
+
+// Decode an item from the connection.
+func (ed *encDec) decode(value reflect.Value) os.Error {
+	ed.decLock.Lock()
+	err := ed.dec.DecodeValue(value)
+	if err != nil {
+		// TODO: tear down connection?
+	}
+	ed.decLock.Unlock()
+	return err
+}
+
+// Encode a header and payload onto the connection.
+func (ed *encDec) encode(hdr *header, payloadType int, payload interface{}) os.Error {
+	ed.encLock.Lock()
+	hdr.PayloadType = payloadType
+	err := ed.enc.Encode(hdr)
+	if err == nil {
+		if payload != nil {
+			err = ed.enc.Encode(payload)
+		}
+	}
+	if err != nil {
+		// TODO: tear down connection if there is an error?
+	}
+	ed.encLock.Unlock()
+	return err
+}
+
+// See the comment for Exporter.Drain.
+func (cs *clientSet) drain(timeout int64) os.Error {
+	startTime := time.Nanoseconds()
+	for {
+		pending := false
+		cs.mu.Lock()
+		// Any messages waiting for a client?
+		for _, chDir := range cs.names {
+			if chDir.ch.Len() > 0 {
+				pending = true
+			}
+		}
+		// Any unacknowledged messages?
+		for client := range cs.clients {
+			n := client.unackedCount()
+			if n > 0 { // Check for > rather than != just to be safe.
+				pending = true
+				break
+			}
+		}
+		cs.mu.Unlock()
+		if !pending {
+			break
+		}
+		if timeout > 0 && time.Nanoseconds()-startTime >= timeout {
+			return os.ErrorString("timeout")
+		}
+		time.Sleep(100 * 1e6) // 100 milliseconds
+	}
+	return nil
+}
+
+// See the comment for Exporter.Sync.
+func (cs *clientSet) sync(timeout int64) os.Error {
+	startTime := time.Nanoseconds()
+	// seq remembers the clients and their seqNum at point of entry.
+	seq := make(map[unackedCounter]int64)
+	for client := range cs.clients {
+		seq[client] = client.seq()
+	}
+	for {
+		pending := false
+		cs.mu.Lock()
+		// Any unacknowledged messages?  Look only at clients that existed
+		// when we started and are still in this client set.
+		for client := range seq {
+			if _, ok := cs.clients[client]; ok {
+				if client.ack() < seq[client] {
+					pending = true
+					break
+				}
+			}
+		}
+		cs.mu.Unlock()
+		if !pending {
+			break
+		}
+		if timeout > 0 && time.Nanoseconds()-startTime >= timeout {
+			return os.ErrorString("timeout")
+		}
+		time.Sleep(100 * 1e6) // 100 milliseconds
+	}
+	return nil
+}
+
+// A netChan represents a channel imported or exported
+// on a single connection. Flow is controlled by the receiving
+// side by sending payAckSend messages when values
+// are delivered into the local channel.
+type netChan struct {
+	*chanDir
+	name string
+	id   int
+	size int // buffer size of channel.
+
+	// sender-specific state
+	ackCh chan bool // buffered with space for all the acks we need
+	space int       // available space.
+
+	// receiver-specific state
+	sendCh chan reflect.Value // buffered channel of values received from other end.
+	ed     *encDec            // so that we can send acks.
+	count  int64              // number of values still to receive.
+}
+
+// Create a new netChan with the given name (only used for
+// messages), id, direction, buffer size, and count.
+// The connection to the other side is represented by ed.
+func newNetChan(name string, id int, ch *chanDir, ed *encDec, size int, count int64) *netChan {
+	c := &netChan{chanDir: ch, name: name, id: id, size: size, ed: ed, count: count}
+	if c.dir == Send {
+		c.ackCh = make(chan bool, size)
+		c.space = size
+	}
+	return c
+}
+
+// Close the channel.
+func (nch *netChan) close() {
+	if nch.dir == Recv {
+		if nch.sendCh != nil {
+			// If the sender goroutine is active, close the channel to it.
+			// It will close nch.ch when it can.
+			close(nch.sendCh)
+		} else {
+			nch.ch.Close()
+		}
+	} else {
+		nch.ch.Close()
+		close(nch.ackCh)
+	}
+}
+
+// Send message from remote side to local receiver.
+func (nch *netChan) send(val reflect.Value) {
+	if nch.dir != Recv {
+		panic("send on wrong direction of channel")
+	}
+	if nch.sendCh == nil {
+		// If possible, do local send directly and ack immediately.
+		if nch.ch.TrySend(val) {
+			nch.sendAck()
+			return
+		}
+		// Start sender goroutine to manage delayed delivery of values.
+		nch.sendCh = make(chan reflect.Value, nch.size)
+		go nch.sender()
+	}
+	if ok := nch.sendCh <- val; !ok {
+		// TODO: should this be more resilient?
+		panic("netchan: remote sender sent more values than allowed")
+	}
+}
+
+// sendAck sends an acknowledgment that a message has left
+// the channel's buffer. If the messages remaining to be sent
+// will fit in the channel's buffer, then we don't
+// need to send an ack.
+func (nch *netChan) sendAck() {
+	if nch.count < 0 || nch.count > int64(nch.size) {
+		nch.ed.encode(&header{Id: nch.id}, payAckSend, nil)
+	}
+	if nch.count > 0 {
+		nch.count--
+	}
+}
+
+// The sender process forwards items from the sending queue
+// to the destination channel, acknowledging each item.
+func (nch *netChan) sender() {
+	if nch.dir != Recv {
+		panic("sender on wrong direction of channel")
+	}
+	// When Exporter.Hangup is called, the underlying channel is closed,
+	// and so we may get a "too many operations on closed channel" error
+	// if there are outstanding messages in sendCh.
+	// Make sure that this doesn't panic the whole program.
+	defer func() {
+		if r := recover(); r != nil {
+			// TODO check that r is "too many operations", otherwise re-panic.
+		}
+	}()
+	for v := range nch.sendCh {
+		nch.ch.Send(v)
+		nch.sendAck()
+	}
+	nch.ch.Close()
+}
+
+// Receive value from local side for sending to remote side.
+func (nch *netChan) recv() (val reflect.Value, closed bool) {
+	if nch.dir != Send {
+		panic("recv on wrong direction of channel")
+	}
+
+	if nch.space == 0 {
+		// Wait for buffer space.
+		<-nch.ackCh
+		nch.space++
+	}
+	nch.space--
+	return nch.ch.Recv(), nch.ch.Closed()
+}
+
+// acked is called when the remote side indicates that
+// a value has been delivered.
+func (nch *netChan) acked() {
+	if nch.dir != Send {
+		panic("recv on wrong direction of channel")
+	}
+	if ok := nch.ackCh <- true; !ok {
+		panic("netchan: remote receiver sent too many acks")
+		// TODO: should this be more resilient?
+	}
+}