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38 lines
1.0 KiB
38 lines
1.0 KiB
// Copyright (c) 2019 FOSS contributors of https://github.com/nxadm/tail
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package watch
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type FileChanges struct {
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Modified chan bool // Channel to get notified of modifications
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Truncated chan bool // Channel to get notified of truncations
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Deleted chan bool // Channel to get notified of deletions/renames
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}
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func NewFileChanges() *FileChanges {
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return &FileChanges{
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make(chan bool, 1), make(chan bool, 1), make(chan bool, 1)}
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}
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func (fc *FileChanges) NotifyModified() {
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sendOnlyIfEmpty(fc.Modified)
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}
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func (fc *FileChanges) NotifyTruncated() {
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sendOnlyIfEmpty(fc.Truncated)
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}
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func (fc *FileChanges) NotifyDeleted() {
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sendOnlyIfEmpty(fc.Deleted)
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}
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// sendOnlyIfEmpty sends on a bool channel only if the channel has no
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// backlog to be read by other goroutines. This concurrency pattern
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// can be used to notify other goroutines if and only if they are
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// looking for it (i.e., subsequent notifications can be compressed
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// into one).
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func sendOnlyIfEmpty(ch chan bool) {
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select {
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case ch <- true:
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default:
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}
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}
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