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authorFelix Lange <fjl@twurst.com>2014-12-12 18:39:07 +0800
committerFelix Lange <fjl@twurst.com>2014-12-15 07:28:20 +0800
commit65e39bf20eecf7f3296fba531efb72ac28dc0124 (patch)
tree6a7f4116bcb1eea1a85176b1542366bccc80222b /p2p
parente28c60caf9a31669451124a9add2b9036bec1e73 (diff)
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p2p: add MsgPipe for protocol testing
Diffstat (limited to 'p2p')
-rw-r--r--p2p/message.go77
-rw-r--r--p2p/message_test.go63
2 files changed, 140 insertions, 0 deletions
diff --git a/p2p/message.go b/p2p/message.go
index d3b8b74d4..f5418ff47 100644
--- a/p2p/message.go
+++ b/p2p/message.go
@@ -3,9 +3,11 @@ package p2p
import (
"bytes"
"encoding/binary"
+ "errors"
"io"
"io/ioutil"
"math/big"
+ "sync/atomic"
"github.com/ethereum/go-ethereum/ethutil"
"github.com/ethereum/go-ethereum/rlp"
@@ -153,3 +155,78 @@ func (r *postrack) ReadByte() (byte, error) {
}
return b, err
}
+
+// MsgPipe creates a message pipe. Reads on one end are matched
+// with writes on the other. The pipe is full-duplex, both ends
+// implement MsgReadWriter.
+func MsgPipe() (*MsgPipeRW, *MsgPipeRW) {
+ var (
+ c1, c2 = make(chan Msg), make(chan Msg)
+ closing = make(chan struct{})
+ closed = new(int32)
+ rw1 = &MsgPipeRW{c1, c2, closing, closed}
+ rw2 = &MsgPipeRW{c2, c1, closing, closed}
+ )
+ return rw1, rw2
+}
+
+// ErrPipeClosed is returned from pipe operations after the
+// pipe has been closed.
+var ErrPipeClosed = errors.New("p2p: read or write on closed message pipe")
+
+// MsgPipeRW is an endpoint of a MsgReadWriter pipe.
+type MsgPipeRW struct {
+ w chan<- Msg
+ r <-chan Msg
+ closing chan struct{}
+ closed *int32
+}
+
+// WriteMsg sends a messsage on the pipe.
+// It blocks until the receiver has consumed the message payload.
+func (p *MsgPipeRW) WriteMsg(msg Msg) error {
+ if atomic.LoadInt32(p.closed) == 0 {
+ consumed := make(chan struct{}, 1)
+ msg.Payload = &eofSignal{msg.Payload, int64(msg.Size), consumed}
+ select {
+ case p.w <- msg:
+ if msg.Size > 0 {
+ // wait for payload read or discard
+ <-consumed
+ }
+ return nil
+ case <-p.closing:
+ }
+ }
+ return ErrPipeClosed
+}
+
+// EncodeMsg is a convenient shorthand for sending an RLP-encoded message.
+func (p *MsgPipeRW) EncodeMsg(code uint64, data ...interface{}) error {
+ return p.WriteMsg(NewMsg(code, data...))
+}
+
+// ReadMsg returns a message sent on the other end of the pipe.
+func (p *MsgPipeRW) ReadMsg() (Msg, error) {
+ if atomic.LoadInt32(p.closed) == 0 {
+ select {
+ case msg := <-p.r:
+ return msg, nil
+ case <-p.closing:
+ }
+ }
+ return Msg{}, ErrPipeClosed
+}
+
+// Close unblocks any pending ReadMsg and WriteMsg calls on both ends
+// of the pipe. They will return ErrPipeClosed. Note that Close does
+// not interrupt any reads from a message payload.
+func (p *MsgPipeRW) Close() error {
+ if atomic.AddInt32(p.closed, 1) != 1 {
+ // someone else is already closing
+ atomic.StoreInt32(p.closed, 1) // avoid overflow
+ return nil
+ }
+ close(p.closing)
+ return nil
+}
diff --git a/p2p/message_test.go b/p2p/message_test.go
index 7b39b061d..0fbcfeef0 100644
--- a/p2p/message_test.go
+++ b/p2p/message_test.go
@@ -2,8 +2,11 @@ package p2p
import (
"bytes"
+ "fmt"
"io/ioutil"
+ "runtime"
"testing"
+ "time"
"github.com/ethereum/go-ethereum/ethutil"
)
@@ -68,3 +71,63 @@ func TestDecodeRealMsg(t *testing.T) {
t.Errorf("incorrect code %d, want %d", msg.Code, 0)
}
}
+
+func ExampleMsgPipe() {
+ rw1, rw2 := MsgPipe()
+ go func() {
+ rw1.EncodeMsg(8, []byte{0, 0})
+ rw1.EncodeMsg(5, []byte{1, 1})
+ rw1.Close()
+ }()
+
+ for {
+ msg, err := rw2.ReadMsg()
+ if err != nil {
+ break
+ }
+ var data [1][]byte
+ msg.Decode(&data)
+ fmt.Printf("msg: %d, %x\n", msg.Code, data[0])
+ }
+ // Output:
+ // msg: 8, 0000
+ // msg: 5, 0101
+}
+
+func TestMsgPipeUnblockWrite(t *testing.T) {
+loop:
+ for i := 0; i < 100; i++ {
+ rw1, rw2 := MsgPipe()
+ done := make(chan struct{})
+ go func() {
+ if err := rw1.EncodeMsg(1); err == nil {
+ t.Error("EncodeMsg returned nil error")
+ } else if err != ErrPipeClosed {
+ t.Error("EncodeMsg returned wrong error: got %v, want %v", err, ErrPipeClosed)
+ }
+ close(done)
+ }()
+
+ // this call should ensure that EncodeMsg is waiting to
+ // deliver sometimes. if this isn't done, Close is likely to
+ // be executed before EncodeMsg starts and then we won't test
+ // all the cases.
+ runtime.Gosched()
+
+ rw2.Close()
+ select {
+ case <-done:
+ case <-time.After(200 * time.Millisecond):
+ t.Errorf("write didn't unblock")
+ break loop
+ }
+ }
+}
+
+// This test should panic if concurrent close isn't implemented correctly.
+func TestMsgPipeConcurrentClose(t *testing.T) {
+ rw1, _ := MsgPipe()
+ for i := 0; i < 10; i++ {
+ go rw1.Close()
+ }
+}