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go/internal/lsp/protocol/protocol.go
Ian Cottrell 1f08ef6002 internal/jsonrpc2: split reply from request
reply is now passed to handlers separately from request, which allows it to be
substituted by handlers.
This also makes the handler signature much closer to http (which has
ResponseWriter)

Change-Id: I12be2e8e8b9bd508982ba43c9092709429284eaf
Reviewed-on: https://go-review.googlesource.com/c/tools/+/227839
Reviewed-by: Robert Findley <rfindley@google.com>
2020-04-13 01:58:12 +00:00

81 lines
2.5 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"
)
var (
// RequestCancelledError should be used when a request is cancelled early.
RequestCancelledError = jsonrpc2.NewError(-32800, "JSON RPC cancelled")
)
// 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.MustReplyHandler(handler))))
}
func CancelHandler(handler jsonrpc2.Handler) jsonrpc2.Handler {
handler, canceller := jsonrpc2.CancelHandler(handler)
return func(ctx context.Context, reply jsonrpc2.Replier, req *jsonrpc2.Request) error {
if req.Method != "$/cancelRequest" {
return handler(ctx, reply, req)
}
var params CancelParams
if err := json.Unmarshal(*req.Params, &params); err != nil {
return sendParseError(ctx, reply, req, err)
}
if n, ok := params.ID.(float64); ok {
canceller(*jsonrpc2.NewIntID(int64(n)))
} else if s, ok := params.ID.(string); ok {
canceller(*jsonrpc2.NewStringID(s))
} else {
return sendParseError(ctx, reply, req, fmt.Errorf("request ID %v malformed", params.ID))
}
return reply(ctx, nil, nil)
}
}
func Call(ctx context.Context, conn *jsonrpc2.Conn, method string, params interface{}, result interface{}) error {
id, err := conn.Call(ctx, method, params, result)
if ctx.Err() != nil {
cancelCall(ctx, conn, id)
}
return err
}
func cancelCall(ctx context.Context, conn *jsonrpc2.Conn, id jsonrpc2.ID) {
ctx = xcontext.Detach(ctx)
ctx, done := event.StartSpan(ctx, "protocol.canceller")
defer done()
// Note that only *jsonrpc2.ID implements json.Marshaler.
conn.Notify(ctx, "$/cancelRequest", &CancelParams{ID: &id})
}
func sendParseError(ctx context.Context, reply jsonrpc2.Replier, req *jsonrpc2.Request, err error) error {
return reply(ctx, nil, fmt.Errorf("%w: %s", jsonrpc2.ErrParse, err))
}