func (eng *Engine) dispatch() bool {
var needTick bool // Set if we need to tick the transport.
for {
if cevent := C.pn_connection_engine_dispatch(&eng.engine); cevent != nil {
event := makeEvent(cevent, eng)
for _, h := range eng.handlers {
switch event.Type() {
case ETransport:
needTick = true
}
h.HandleEvent(event)
}
} else {
break
}
}
if needTick {
eng.tick()
}
return !bool(C.pn_connection_engine_finished(&eng.engine))
}
// Run the engine. Engine.Run() will exit when the engine is closed or
// disconnected. You can check for errors after exit with Engine.Error().
//
func (eng *Engine) Run() error {
// Channels for read and write buffers going in and out of the read/write goroutines.
// The channels are unbuffered: we want to exchange buffers in seuquence.
readsIn, writesIn := make(chan []byte), make(chan []byte)
readsOut, writesOut := make(chan []byte), make(chan []byte)
wait := sync.WaitGroup{}
wait.Add(2) // Read and write goroutines
go func() { // Read goroutine
defer wait.Done()
for {
rbuf, ok := <-readsIn
if !ok {
return
}
n, err := eng.conn.Read(rbuf)
if n > 0 {
readsOut <- rbuf[:n]
} else if err != nil {
eng.inject <- func() {
eng.Transport().Condition().SetError(err)
C.pn_connection_engine_read_close(&eng.engine)
}
return
}
}
}()
go func() { // Write goroutine
defer wait.Done()
for {
wbuf, ok := <-writesIn
if !ok {
return
}
n, err := eng.conn.Write(wbuf)
if n > 0 {
writesOut <- wbuf[:n]
} else if err != nil {
eng.inject <- func() {
eng.Transport().Condition().SetError(err)
C.pn_connection_engine_write_close(&eng.engine)
}
return
}
}
}()
for !C.pn_connection_engine_finished(&eng.engine) {
// Enable readIn/writeIn channles only if we have a buffer.
readBuf, writeBuf := eng.buffers()
var sendReads, sendWrites chan []byte
if readBuf != nil {
sendReads = readsIn
}
if writeBuf != nil {
sendWrites = writesIn
}
// Send buffers to the read/write goroutines if we have them.
// Get buffers from the read/write goroutines and process them
select {
case sendReads <- readBuf:
case sendWrites <- writeBuf:
case buf := <-readsOut:
if len(buf) > 0 {
C.pn_connection_engine_read_done(&eng.engine, C.size_t(len(buf)))
} else {
panic(fmt.Sprintf("read buf %v", buf))
}
case buf := <-writesOut:
if len(buf) > 0 {
C.pn_connection_engine_write_done(&eng.engine, C.size_t(len(buf)))
} else {
panic(fmt.Sprintf("write buf %v", buf))
}
case f, ok := <-eng.inject: // Function injected from another goroutine
if ok {
f()
}
}
for {
cevent := C.pn_connection_engine_dispatch(&eng.engine)
if cevent == nil {
break
}
event := makeEvent(cevent, eng)
for _, h := range eng.handlers {
h.HandleEvent(event)
}
}
}
eng.err.Set(EndpointError(eng.Connection()))
eng.err.Set(eng.Transport().Condition().Error())
close(readsIn)
close(writesIn)
eng.conn.Close() // Make sure connection is closed
wait.Wait() // Wait for goroutines
close(eng.running) // Signal goroutines have exited and Error is set.
C.pn_connection_engine_final(&eng.engine)
for _, h := range eng.handlers {
switch h := h.(type) {
case cHandler:
C.pn_handler_free(h.pn)
}
}
// FIXME aconway 2016-06-21: consistent error handling
return eng.err.Get()
}