--- /dev/null
+// Copyright 2018 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 jsonrpc2
+
+import (
+ "context"
+ "encoding/json"
+ "fmt"
+ "sync"
+ "sync/atomic"
+
+ "golang.org/x/tools/internal/event"
+ "golang.org/x/tools/internal/event/label"
+ "golang.org/x/tools/internal/lsp/debug/tag"
+)
+
+// Conn is the common interface to jsonrpc clients and servers.
+// Conn is bidirectional; it does not have a designated server or client end.
+// It manages the jsonrpc2 protocol, connecting responses back to their calls.
+type Conn interface {
+ // Call invokes the target method and waits for a response.
+ // The params will be marshaled to JSON before sending over the wire, and will
+ // be handed to the method invoked.
+ // The response will be unmarshaled from JSON into the result.
+ // The id returned will be unique from this connection, and can be used for
+ // logging or tracking.
+ Call(ctx context.Context, method string, params, result interface{}) (ID, error)
+
+ // Notify invokes the target method but does not wait for a response.
+ // The params will be marshaled to JSON before sending over the wire, and will
+ // be handed to the method invoked.
+ Notify(ctx context.Context, method string, params interface{}) error
+
+ // Go starts a goroutine to handle the connection.
+ // It must be called exactly once for each Conn.
+ // It returns immediately.
+ // You must block on Done() to wait for the connection to shut down.
+ // This is a temporary measure, this should be started automatically in the
+ // future.
+ Go(ctx context.Context, handler Handler)
+
+ // Close closes the connection and it's underlying stream.
+ // It does not wait for the close to complete, use the Done() channel for
+ // that.
+ Close() error
+
+ // Done returns a channel that will be closed when the processing goroutine
+ // has terminated, which will happen if Close() is called or an underlying
+ // stream is closed.
+ Done() <-chan struct{}
+
+ // Err returns an error if there was one from within the processing goroutine.
+ // If err returns non nil, the connection will be already closed or closing.
+ Err() error
+}
+
+type conn struct {
+ seq int64 // must only be accessed using atomic operations
+ writeMu sync.Mutex // protects writes to the stream
+ stream Stream
+ pendingMu sync.Mutex // protects the pending map
+ pending map[ID]chan *Response
+
+ done chan struct{}
+ err atomic.Value
+}
+
+// NewConn creates a new connection object around the supplied stream.
+func NewConn(s Stream) Conn {
+ conn := &conn{
+ stream: s,
+ pending: make(map[ID]chan *Response),
+ done: make(chan struct{}),
+ }
+ return conn
+}
+
+func (c *conn) Notify(ctx context.Context, method string, params interface{}) (err error) {
+ notify, err := NewNotification(method, params)
+ if err != nil {
+ return fmt.Errorf("marshaling notify parameters: %v", err)
+ }
+ ctx, done := event.Start(ctx, method,
+ tag.Method.Of(method),
+ tag.RPCDirection.Of(tag.Outbound),
+ )
+ defer func() {
+ recordStatus(ctx, err)
+ done()
+ }()
+
+ event.Metric(ctx, tag.Started.Of(1))
+ n, err := c.write(ctx, notify)
+ event.Metric(ctx, tag.SentBytes.Of(n))
+ return err
+}
+
+func (c *conn) Call(ctx context.Context, method string, params, result interface{}) (_ ID, err error) {
+ // generate a new request identifier
+ id := ID{number: atomic.AddInt64(&c.seq, 1)}
+ call, err := NewCall(id, method, params)
+ if err != nil {
+ return id, fmt.Errorf("marshaling call parameters: %v", err)
+ }
+ ctx, done := event.Start(ctx, method,
+ tag.Method.Of(method),
+ tag.RPCDirection.Of(tag.Outbound),
+ tag.RPCID.Of(fmt.Sprintf("%q", id)),
+ )
+ defer func() {
+ recordStatus(ctx, err)
+ done()
+ }()
+ event.Metric(ctx, tag.Started.Of(1))
+ // We have to add ourselves to the pending map before we send, otherwise we
+ // are racing the response. Also add a buffer to rchan, so that if we get a
+ // wire response between the time this call is cancelled and id is deleted
+ // from c.pending, the send to rchan will not block.
+ rchan := make(chan *Response, 1)
+ c.pendingMu.Lock()
+ c.pending[id] = rchan
+ c.pendingMu.Unlock()
+ defer func() {
+ c.pendingMu.Lock()
+ delete(c.pending, id)
+ c.pendingMu.Unlock()
+ }()
+ // now we are ready to send
+ n, err := c.write(ctx, call)
+ event.Metric(ctx, tag.SentBytes.Of(n))
+ if err != nil {
+ // sending failed, we will never get a response, so don't leave it pending
+ return id, err
+ }
+ // now wait for the response
+ select {
+ case response := <-rchan:
+ // is it an error response?
+ if response.err != nil {
+ return id, response.err
+ }
+ if result == nil || len(response.result) == 0 {
+ return id, nil
+ }
+ if err := json.Unmarshal(response.result, result); err != nil {
+ return id, fmt.Errorf("unmarshaling result: %v", err)
+ }
+ return id, nil
+ case <-ctx.Done():
+ return id, ctx.Err()
+ }
+}
+
+func (c *conn) replier(req Request, spanDone func()) Replier {
+ return func(ctx context.Context, result interface{}, err error) error {
+ defer func() {
+ recordStatus(ctx, err)
+ spanDone()
+ }()
+ call, ok := req.(*Call)
+ if !ok {
+ // request was a notify, no need to respond
+ return nil
+ }
+ response, err := NewResponse(call.id, result, err)
+ if err != nil {
+ return err
+ }
+ n, err := c.write(ctx, response)
+ event.Metric(ctx, tag.SentBytes.Of(n))
+ if err != nil {
+ // TODO(iancottrell): if a stream write fails, we really need to shut down
+ // the whole stream
+ return err
+ }
+ return nil
+ }
+}
+
+func (c *conn) write(ctx context.Context, msg Message) (int64, error) {
+ c.writeMu.Lock()
+ defer c.writeMu.Unlock()
+ return c.stream.Write(ctx, msg)
+}
+
+func (c *conn) Go(ctx context.Context, handler Handler) {
+ go c.run(ctx, handler)
+}
+
+func (c *conn) run(ctx context.Context, handler Handler) {
+ defer close(c.done)
+ for {
+ // get the next message
+ msg, n, err := c.stream.Read(ctx)
+ if err != nil {
+ // The stream failed, we cannot continue.
+ c.fail(err)
+ return
+ }
+ switch msg := msg.(type) {
+ case Request:
+ labels := []label.Label{
+ tag.Method.Of(msg.Method()),
+ tag.RPCDirection.Of(tag.Inbound),
+ {}, // reserved for ID if present
+ }
+ if call, ok := msg.(*Call); ok {
+ labels[len(labels)-1] = tag.RPCID.Of(fmt.Sprintf("%q", call.ID()))
+ } else {
+ labels = labels[:len(labels)-1]
+ }
+ reqCtx, spanDone := event.Start(ctx, msg.Method(), labels...)
+ event.Metric(reqCtx,
+ tag.Started.Of(1),
+ tag.ReceivedBytes.Of(n))
+ if err := handler(reqCtx, c.replier(msg, spanDone), msg); err != nil {
+ // delivery failed, not much we can do
+ event.Error(reqCtx, "jsonrpc2 message delivery failed", err)
+ }
+ case *Response:
+ // If method is not set, this should be a response, in which case we must
+ // have an id to send the response back to the caller.
+ c.pendingMu.Lock()
+ rchan, ok := c.pending[msg.id]
+ c.pendingMu.Unlock()
+ if ok {
+ rchan <- msg
+ }
+ }
+ }
+}
+
+func (c *conn) Close() error {
+ return c.stream.Close()
+}
+
+func (c *conn) Done() <-chan struct{} {
+ return c.done
+}
+
+func (c *conn) Err() error {
+ if err := c.err.Load(); err != nil {
+ return err.(error)
+ }
+ return nil
+}
+
+// fail sets a failure condition on the stream and closes it.
+func (c *conn) fail(err error) {
+ c.err.Store(err)
+ c.stream.Close()
+}
+
+func recordStatus(ctx context.Context, err error) {
+ if err != nil {
+ event.Label(ctx, tag.StatusCode.Of("ERROR"))
+ } else {
+ event.Label(ctx, tag.StatusCode.Of("OK"))
+ }
+}
projects / dotfiles / .git / blobdiff