146 lines
3.6 KiB
Go
146 lines
3.6 KiB
Go
// Copyright (c) 2014-2017, b3log.org & hacpai.com
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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 event includes event related manipulations.
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package event
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import (
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"os"
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"github.com/b3log/wide/log"
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"github.com/b3log/wide/util"
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)
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const (
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// EvtCodeGOPATHNotFound indicates an event: not found $GOPATH env variable
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EvtCodeGOPATHNotFound = iota
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// EvtCodeGOROOTNotFound indicates an event: not found $GOROOT env variable
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EvtCodeGOROOTNotFound
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// EvtCodeGocodeNotFound indicates an event: not found gocode
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EvtCodeGocodeNotFound
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// EvtCodeIDEStubNotFound indicates an event: not found gotools
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EvtCodeIDEStubNotFound
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// EvtCodeServerInternalError indicates an event: server internal error
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EvtCodeServerInternalError
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)
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// Max length of queue.
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const maxQueueLength = 10
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// Logger.
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var logger = log.NewLogger(os.Stdout)
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// Event represents an event.
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type Event struct {
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Code int `json:"code"` // event code
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Sid string `json:"sid"` // wide session id related
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Data interface{} `json:"data"` // event data
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}
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// Global event queue.
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//
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// Every event in this queue will be dispatched to each user event queue.
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var EventQueue = make(chan *Event, maxQueueLength)
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// UserEventQueue represents a user event queue.
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type UserEventQueue struct {
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Sid string // wide session id related
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Queue chan *Event // queue
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Handlers []Handler // event handlers
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}
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type queues map[string]*UserEventQueue
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// User event queues.
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//
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// <sid, *UserEventQueue>
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var UserEventQueues = queues{}
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// Load initializes the event handling.
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func Load() {
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go func() {
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defer util.Recover()
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for event := range EventQueue {
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logger.Debugf("Received a global event [code=%d]", event.Code)
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// dispatch the event to each user event queue
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for _, userQueue := range UserEventQueues {
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event.Sid = userQueue.Sid
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userQueue.Queue <- event
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}
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}
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}()
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}
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// AddHandler adds the specified handlers to user event queues.
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func (uq *UserEventQueue) AddHandler(handlers ...Handler) {
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uq.Handlers = append(uq.Handlers, handlers...)
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}
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// New initializes a user event queue with the specified wide session id.
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func (ueqs queues) New(sid string) *UserEventQueue {
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if q, ok := ueqs[sid]; ok {
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logger.Warnf("Already exist a user queue in session [%s]", sid)
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return q
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}
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q := &UserEventQueue{
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Sid: sid,
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Queue: make(chan *Event, maxQueueLength),
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}
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ueqs[sid] = q
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go func() { // start listening
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defer util.Recover()
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for evt := range q.Queue {
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logger.Debugf("Session [%s] received an event [%d]", sid, evt.Code)
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// process event by each handlers
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for _, handler := range q.Handlers {
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handler.Handle(evt)
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}
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}
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}()
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return q
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}
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// Close closes a user event queue with the specified wide session id.
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func (ueqs queues) Close(sid string) {
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if q, ok := ueqs[sid]; ok {
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close(q.Queue)
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delete(ueqs, sid)
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}
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}
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// Handler represents an event handler.
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type Handler interface {
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Handle(event *Event)
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}
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// HandleFunc represents a handler function.
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type HandleFunc func(event *Event)
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// Default implementation of event handling.
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func (fn HandleFunc) Handle(event *Event) {
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fn(event)
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}
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