73 lines
1.5 KiB
Go
73 lines
1.5 KiB
Go
// Copyright 2019 Drone IO, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package pubsub
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import (
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"context"
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"sync"
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"github.com/drone/drone/core"
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)
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type hub struct {
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sync.Mutex
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subs map[*subscriber]struct{}
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}
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// New creates a new publish subscriber.
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func New() core.Pubsub {
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return &hub{
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subs: map[*subscriber]struct{}{},
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}
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}
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func (h *hub) Publish(ctx context.Context, e *core.Message) error {
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h.Lock()
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for s := range h.subs {
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s.publish(e)
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}
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h.Unlock()
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return nil
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}
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func (h *hub) Subscribe(ctx context.Context) (<-chan *core.Message, <-chan error) {
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h.Lock()
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s := &subscriber{
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handler: make(chan *core.Message, 100),
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quit: make(chan struct{}),
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}
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h.subs[s] = struct{}{}
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h.Unlock()
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errc := make(chan error)
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go func() {
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defer close(errc)
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select {
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case <-ctx.Done():
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h.Lock()
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delete(h.subs, s)
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h.Unlock()
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s.close()
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}
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}()
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return s.handler, errc
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}
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func (h *hub) Subscribers() int {
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h.Lock()
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c := len(h.subs)
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h.Unlock()
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return c
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}
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