104 lines
3.1 KiB
Go
104 lines
3.1 KiB
Go
// Copyright (C) 2023 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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package model
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import (
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"context"
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"fmt"
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"time"
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"github.com/syncthing/syncthing/lib/events"
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"github.com/syncthing/syncthing/lib/svcutil"
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"github.com/thejerf/suture/v4"
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)
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// A serviceMap is a utility map of arbitrary keys to a suture.Service of
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// some kind, where adding and removing services ensures they are properly
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// started and stopped on the given Supervisor. The serviceMap is itself a
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// suture.Service and should be added to a Supervisor.
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// Not safe for concurrent use.
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type serviceMap[K comparable, S suture.Service] struct {
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services map[K]S
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tokens map[K]suture.ServiceToken
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supervisor *suture.Supervisor
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eventLogger events.Logger
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}
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func newServiceMap[K comparable, S suture.Service](eventLogger events.Logger) *serviceMap[K, S] {
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m := &serviceMap[K, S]{
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services: make(map[K]S),
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tokens: make(map[K]suture.ServiceToken),
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eventLogger: eventLogger,
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}
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m.supervisor = suture.New(m.String(), svcutil.SpecWithDebugLogger(l))
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return m
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}
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// Add adds a service to the map, starting it on the supervisor. If there is
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// already a service at the given key, it is removed first.
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func (s *serviceMap[K, S]) Add(k K, v S) {
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if tok, ok := s.tokens[k]; ok {
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// There is already a service at this key, remove it first.
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s.supervisor.Remove(tok)
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s.eventLogger.Log(events.Failure, fmt.Sprintf("%s replaced service at key %v", s, k))
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}
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s.services[k] = v
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s.tokens[k] = s.supervisor.Add(v)
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}
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// Get returns the service at the given key, or the empty value and false if
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// there is no service at that key.
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func (s *serviceMap[K, S]) Get(k K) (v S, ok bool) {
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v, ok = s.services[k]
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return
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}
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// Remove removes the service at the given key, stopping it on the supervisor.
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// If there is no service at the given key, nothing happens. The return value
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// indicates whether a service was removed.
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func (s *serviceMap[K, S]) Remove(k K) (found bool) {
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if tok, ok := s.tokens[k]; ok {
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found = true
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s.supervisor.Remove(tok)
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}
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delete(s.services, k)
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delete(s.tokens, k)
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return
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}
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// RemoveAndWait removes the service at the given key, stopping it on the
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// supervisor. If there is no service at the given key, nothing happens. The
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// return value indicates whether a service was removed.
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func (s *serviceMap[K, S]) RemoveAndWait(k K, timeout time.Duration) (found bool) {
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if tok, ok := s.tokens[k]; ok {
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found = true
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s.supervisor.RemoveAndWait(tok, timeout)
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}
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delete(s.services, k)
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delete(s.tokens, k)
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return found
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}
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// Each calls the given function for each service in the map.
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func (s *serviceMap[K, S]) Each(fn func(K, S)) {
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for key, svc := range s.services {
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fn(key, svc)
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}
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}
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// Suture implementation
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func (s *serviceMap[K, S]) Serve(ctx context.Context) error {
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return s.supervisor.Serve(ctx)
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}
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func (s *serviceMap[K, S]) String() string {
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var kv K
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var sv S
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return fmt.Sprintf("serviceMap[%T, %T]@%p", kv, sv, s)
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}
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