mirror of https://github.com/golang/go.git
94 lines
2.5 KiB
Go
94 lines
2.5 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package jsonrpc2 is a minimal implementation of the JSON RPC 2 spec.
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// https://www.jsonrpc.org/specification
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// It is intended to be compatible with other implementations at the wire level.
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package jsonrpc2
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import (
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"context"
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"errors"
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)
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var (
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// ErrIdleTimeout is returned when serving timed out waiting for new connections.
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ErrIdleTimeout = errors.New("timed out waiting for new connections")
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// ErrNotHandled is returned from a handler to indicate it did not handle the
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// message.
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ErrNotHandled = errors.New("JSON RPC not handled")
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// ErrAsyncResponse is returned from a handler to indicate it will generate a
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// response asynchronously.
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ErrAsyncResponse = errors.New("JSON RPC asynchronous response")
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)
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// Preempter handles messages on a connection before they are queued to the main
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// handler.
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// Primarily this is used for cancel handlers or notifications for which out of
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// order processing is not an issue.
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type Preempter interface {
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// Preempt is invoked for each incoming request before it is queued.
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// If the request is a call, it must return a value or an error for the reply.
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// Preempt should not block or start any new messages on the connection.
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Preempt(ctx context.Context, req *Request) (interface{}, error)
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}
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// Handler handles messages on a connection.
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type Handler interface {
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// Handle is invoked for each incoming request.
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// If the request is a call, it must return a value or an error for the reply.
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Handle(ctx context.Context, req *Request) (interface{}, error)
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}
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type defaultHandler struct{}
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func (defaultHandler) Preempt(context.Context, *Request) (interface{}, error) {
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return nil, ErrNotHandled
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}
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func (defaultHandler) Handle(context.Context, *Request) (interface{}, error) {
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return nil, ErrNotHandled
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}
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// async is a small helper for things with an asynchronous result that you can
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// wait for.
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type async struct {
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ready chan struct{}
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errBox chan error
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}
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func (a *async) init() {
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a.ready = make(chan struct{})
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a.errBox = make(chan error, 1)
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a.errBox <- nil
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}
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func (a *async) done() {
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close(a.ready)
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}
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func (a *async) isDone() bool {
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select {
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case <-a.ready:
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return true
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default:
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return false
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}
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}
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func (a *async) wait() error {
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<-a.ready
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err := <-a.errBox
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a.errBox <- err
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return err
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}
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func (a *async) setError(err error) {
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storedErr := <-a.errBox
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if storedErr == nil {
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storedErr = err
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}
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a.errBox <- storedErr
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}
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