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go/internal/lsp/protocol/protocol.go
Ian Cottrell ae9902aceb internal/lsp: remove the CallCanceller
This required changing the jsonrpc.Conn.Call signature to also return the
request ID so it can be cancelled.
The protocol package now declares the Call function which wrapps up
Conn.Call and then sends a cancel message if the context was
cancelled during the call.
There is a small chance that a context can be cancelled on a
request that has already completed, but it is safe to do so.

Change-Id: Ic8040c193e1dd4ef376ad21194b1d0ea82145976
Reviewed-on: https://go-review.googlesource.com/c/tools/+/227558
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2020-04-10 13:26:12 +00:00

86 lines
2.4 KiB
Go

// 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 protocol
import (
"context"
"encoding/json"
"fmt"
"golang.org/x/tools/internal/jsonrpc2"
"golang.org/x/tools/internal/telemetry/event"
"golang.org/x/tools/internal/xcontext"
)
const (
// RequestCancelledError should be used when a request is cancelled early.
RequestCancelledError = -32800
)
// ClientDispatcher returns a Client that dispatches LSP requests across the
// given jsonrpc2 connection.
func ClientDispatcher(conn *jsonrpc2.Conn) Client {
return &clientDispatcher{Conn: conn}
}
// ServerDispatcher returns a Server that dispatches LSP requests across the
// given jsonrpc2 connection.
func ServerDispatcher(conn *jsonrpc2.Conn) Server {
return &serverDispatcher{Conn: conn}
}
func Handlers(handler jsonrpc2.Handler) jsonrpc2.Handler {
return CancelHandler(
CancelHandler(
jsonrpc2.AsyncHandler(
jsonrpc2.MustReply(handler))))
}
func CancelHandler(handler jsonrpc2.Handler) jsonrpc2.Handler {
handler, canceller := jsonrpc2.CancelHandler(handler)
return func(ctx context.Context, req *jsonrpc2.Request) error {
if req.Method != "$/cancelRequest" {
return handler(ctx, req)
}
var params CancelParams
if err := json.Unmarshal(*req.Params, &params); err != nil {
return sendParseError(ctx, req, err)
}
v := jsonrpc2.ID{}
if n, ok := params.ID.(float64); ok {
v.Number = int64(n)
} else if s, ok := params.ID.(string); ok {
v.Name = s
} else {
return sendParseError(ctx, req, fmt.Errorf("Request ID %v malformed", params.ID))
}
canceller(v)
return req.Reply(ctx, nil, nil)
}
}
func Call(ctx context.Context, conn *jsonrpc2.Conn, method string, params interface{}, result interface{}) error {
id, err := conn.Call(ctx, method, params, result)
if ctx.Err() != nil {
cancelCall(ctx, conn, id)
}
return err
}
func cancelCall(ctx context.Context, conn *jsonrpc2.Conn, id jsonrpc2.ID) {
ctx = xcontext.Detach(ctx)
ctx, done := event.StartSpan(ctx, "protocol.canceller")
defer done()
// Note that only *jsonrpc2.ID implements json.Marshaler.
conn.Notify(ctx, "$/cancelRequest", &CancelParams{ID: &id})
}
func sendParseError(ctx context.Context, req *jsonrpc2.Request, err error) error {
if _, ok := err.(*jsonrpc2.Error); !ok {
err = jsonrpc2.NewErrorf(jsonrpc2.CodeParseError, "%v", err)
}
return req.Reply(ctx, nil, err)
}