07f542b4d7
Done with: ack '2018+' -l | xargs sed -i -e 's/2018+/2019+/g' Checked manually with: git add -p Hello to future James from 2020, and Happy Hacking!
116 lines
3.2 KiB
Go
116 lines
3.2 KiB
Go
// Mgmt
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// Copyright (C) 2013-2019+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package util
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import (
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"sync"
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)
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// EasyAck is a wrapper to build ack functionality into a simple interface.
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type EasyAck struct {
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done chan struct{}
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}
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// NewEasyAck builds the object. This must be called before use.
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func NewEasyAck() *EasyAck {
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return &EasyAck{
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done: make(chan struct{}),
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}
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}
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// Ack sends the acknowledgment message. This can only be called once.
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func (obj *EasyAck) Ack() {
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close(obj.done)
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}
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// Wait returns a channel that you can wait on for the ack message.
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func (obj *EasyAck) Wait() <-chan struct{} {
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return obj.done
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}
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// EasyOnce is a wrapper for the sync.Once functionality which lets you define
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// and register the associated `run once` function at declaration time. It may
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// be copied at any time.
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type EasyOnce struct {
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Func func()
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once *sync.Once
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}
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// Done runs the function which was defined in `Func` a maximum of once. Please
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// note that this is not currently thread-safe. Wrap calls to this with a mutex.
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func (obj *EasyOnce) Done() {
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if obj.once == nil {
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// we must initialize it!
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obj.once = &sync.Once{}
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}
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if obj.Func != nil {
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obj.once.Do(obj.Func)
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}
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}
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// EasyExit is a struct that helps you build a close switch and signal which can
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// be called multiple times safely, and used as a signal many times in parallel.
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type EasyExit struct {
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mutex *sync.Mutex
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exit chan struct{}
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once *sync.Once
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err error
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}
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// NewEasyExit builds an easy exit struct.
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func NewEasyExit() *EasyExit {
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return &EasyExit{
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mutex: &sync.Mutex{},
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exit: make(chan struct{}),
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once: &sync.Once{},
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}
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}
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// Done triggers the exit signal. It associates an error condition with it too.
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// This is thread-safe.
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func (obj *EasyExit) Done(err error) {
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obj.mutex.Lock()
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defer obj.mutex.Unlock()
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if obj.once == nil { // redundant
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// we must initialize it!
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obj.once = &sync.Once{}
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}
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if err != nil {
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// TODO: we could add a mutex, and turn this into a multierr
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obj.err = err
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}
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obj.once.Do(func() { close(obj.exit) })
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}
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// Signal returns the channel that we watch for the exit signal on. It will
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// close to signal us when triggered by Exit().
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func (obj *EasyExit) Signal() <-chan struct{} {
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return obj.exit
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}
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// Error returns the error condition associated with the Done signal. It blocks
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// until Done is called at least once. It then returns any of the errors or nil.
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// It is only guaranteed to at least return the error from the first Done error.
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func (obj *EasyExit) Error() error {
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select {
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case <-obj.exit:
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}
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return obj.err
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}
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