/usr/share/gocode/src/github.com/cenk/rpc2/client.go is in golang-github-cenk-rpc2-dev 0.0~git20160427.0.7ab76d2e88c7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 | // Package rpc2 provides bi-directional RPC client and server similar to net/rpc.
package rpc2
import (
"errors"
"io"
"log"
"reflect"
"sync"
)
// Client represents an RPC Client.
// There may be multiple outstanding Calls associated
// with a single Client, and a Client may be used by
// multiple goroutines simultaneously.
type Client struct {
mutex sync.Mutex // protects pending, seq, request
sending sync.Mutex
request Request // temp area used in send()
seq uint64
pending map[uint64]*Call
closing bool
shutdown bool
server bool
codec Codec
handlers map[string]*handler
disconnect chan struct{}
State *State // additional information to associate with client
}
// NewClient returns a new Client to handle requests to the
// set of services at the other end of the connection.
// It adds a buffer to the write side of the connection so
// the header and payload are sent as a unit.
func NewClient(conn io.ReadWriteCloser) *Client {
return NewClientWithCodec(newGobCodec(conn))
}
// NewClientWithCodec is like NewClient but uses the specified
// codec to encode requests and decode responses.
func NewClientWithCodec(codec Codec) *Client {
return &Client{
codec: codec,
pending: make(map[uint64]*Call),
handlers: make(map[string]*handler),
disconnect: make(chan struct{}),
seq: 1, // 0 means notification.
}
}
// Run the client's read loop.
// You must run this method before calling any methods on the server.
func (c *Client) Run() {
c.readLoop()
}
// DisconnectNotify returns a channel that is closed
// when the client connection has gone away.
func (c *Client) DisconnectNotify() chan struct{} {
return c.disconnect
}
// Handle registers the handler function for the given method. If a handler already exists for method, Handle panics.
func (c *Client) Handle(method string, handlerFunc interface{}) {
addHandler(c.handlers, method, handlerFunc)
}
// readLoop reads messages from codec.
// It reads a reqeust or a response to the previous request.
// If the message is request, calls the handler function.
// If the message is response, sends the reply to the associated call.
func (c *Client) readLoop() {
var err error
var req Request
var resp Response
for err == nil {
req = Request{}
resp = Response{}
if err = c.codec.ReadHeader(&req, &resp); err != nil {
break
}
if req.Method != "" {
// request comes to server
if err = c.readRequest(&req); err != nil {
log.Println("rpc2: error reading request:", err.Error())
}
} else {
// response comes to client
if err = c.readResponse(&resp); err != nil {
log.Println("rpc2: error reading response:", err.Error())
}
}
}
// Terminate pending calls.
c.sending.Lock()
c.mutex.Lock()
c.shutdown = true
closing := c.closing
if err == io.EOF {
if closing {
err = ErrShutdown
} else {
err = io.ErrUnexpectedEOF
}
}
for _, call := range c.pending {
call.Error = err
call.done()
}
c.mutex.Unlock()
c.sending.Unlock()
if err != io.EOF && !closing && !c.server {
log.Println("rpc2: client protocol error:", err)
}
close(c.disconnect)
}
func (c *Client) readRequest(req *Request) error {
method, ok := c.handlers[req.Method]
if !ok {
resp := &Response{
Seq: req.Seq,
Error: "rpc2: can't find method " + req.Method,
}
return c.codec.WriteResponse(resp, resp)
}
// Decode the argument value.
var argv reflect.Value
argIsValue := false // if true, need to indirect before calling.
if method.argType.Kind() == reflect.Ptr {
argv = reflect.New(method.argType.Elem())
} else {
argv = reflect.New(method.argType)
argIsValue = true
}
// argv guaranteed to be a pointer now.
if err := c.codec.ReadRequestBody(argv.Interface()); err != nil {
return err
}
if argIsValue {
argv = argv.Elem()
}
// Invoke the method, providing a new value for the reply.
replyv := reflect.New(method.replyType.Elem())
// Call handler function.
go func(req Request) {
returnValues := method.fn.Call([]reflect.Value{reflect.ValueOf(c), argv, replyv})
// Do not send response if request is a notification.
if req.Seq == 0 {
return
}
// The return value for the method is an error.
errInter := returnValues[0].Interface()
errmsg := ""
if errInter != nil {
errmsg = errInter.(error).Error()
}
resp := &Response{
Seq: req.Seq,
Error: errmsg,
}
c.codec.WriteResponse(resp, replyv.Interface())
}(*req)
return nil
}
func (c *Client) readResponse(resp *Response) error {
seq := resp.Seq
c.mutex.Lock()
call := c.pending[seq]
delete(c.pending, seq)
c.mutex.Unlock()
var err error
switch {
case call == nil:
// We've got no pending call. That usually means that
// WriteRequest partially failed, and call was already
// removed; response is a server telling us about an
// error reading request body. We should still attempt
// to read error body, but there's no one to give it to.
err = c.codec.ReadResponseBody(nil)
if err != nil {
err = errors.New("reading error body: " + err.Error())
}
case resp.Error != "":
// We've got an error response. Give this to the request;
// any subsequent requests will get the ReadResponseBody
// error if there is one.
call.Error = ServerError(resp.Error)
err = c.codec.ReadResponseBody(nil)
if err != nil {
err = errors.New("reading error body: " + err.Error())
}
call.done()
default:
err = c.codec.ReadResponseBody(call.Reply)
if err != nil {
call.Error = errors.New("reading body " + err.Error())
}
call.done()
}
return nil
}
// Close waits for active calls to finish and closes the codec.
func (c *Client) Close() error {
c.mutex.Lock()
if c.shutdown || c.closing {
c.mutex.Unlock()
return ErrShutdown
}
c.closing = true
c.mutex.Unlock()
return c.codec.Close()
}
// Go invokes the function asynchronously. It returns the Call structure representing
// the invocation. The done channel will signal when the call is complete by returning
// the same Call object. If done is nil, Go will allocate a new channel.
// If non-nil, done must be buffered or Go will deliberately crash.
func (c *Client) Go(method string, args interface{}, reply interface{}, done chan *Call) *Call {
call := new(Call)
call.Method = method
call.Args = args
call.Reply = reply
if done == nil {
done = make(chan *Call, 10) // buffered.
} else {
// If caller passes done != nil, it must arrange that
// done has enough buffer for the number of simultaneous
// RPCs that will be using that channel. If the channel
// is totally unbuffered, it's best not to run at all.
if cap(done) == 0 {
log.Panic("rpc2: done channel is unbuffered")
}
}
call.Done = done
c.send(call)
return call
}
// Call invokes the named function, waits for it to complete, and returns its error status.
func (c *Client) Call(method string, args interface{}, reply interface{}) error {
call := <-c.Go(method, args, reply, make(chan *Call, 1)).Done
return call.Error
}
func (call *Call) done() {
select {
case call.Done <- call:
// ok
default:
// We don't want to block here. It is the caller's responsibility to make
// sure the channel has enough buffer space. See comment in Go().
log.Println("rpc2: discarding Call reply due to insufficient Done chan capacity")
}
}
// ServerError represents an error that has been returned from
// the remote side of the RPC connection.
type ServerError string
func (e ServerError) Error() string {
return string(e)
}
var ErrShutdown = errors.New("connection is shut down")
// Call represents an active RPC.
type Call struct {
Method string // The name of the service and method to call.
Args interface{} // The argument to the function (*struct).
Reply interface{} // The reply from the function (*struct).
Error error // After completion, the error status.
Done chan *Call // Strobes when call is complete.
}
func (c *Client) send(call *Call) {
c.sending.Lock()
defer c.sending.Unlock()
// Register this call.
c.mutex.Lock()
if c.shutdown || c.closing {
call.Error = ErrShutdown
c.mutex.Unlock()
call.done()
return
}
seq := c.seq
c.seq++
c.pending[seq] = call
c.mutex.Unlock()
// Encode and send the request.
c.request.Seq = seq
c.request.Method = call.Method
err := c.codec.WriteRequest(&c.request, call.Args)
if err != nil {
c.mutex.Lock()
call = c.pending[seq]
delete(c.pending, seq)
c.mutex.Unlock()
if call != nil {
call.Error = err
call.done()
}
}
}
func (c *Client) Notify(method string, args interface{}) error {
c.sending.Lock()
defer c.sending.Unlock()
if c.shutdown || c.closing {
return ErrShutdown
}
c.request.Seq = 0
c.request.Method = method
return c.codec.WriteRequest(&c.request, args)
}
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