53 lines
1.1 KiB
Go
53 lines
1.1 KiB
Go
package iotools
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import "io"
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// NopCloser is an empty
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// implementation of io.Closer,
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// that simply does nothing!
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type NopCloser struct{}
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func (NopCloser) Close() error { return nil }
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// CloserFunc is a function signature which allows
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// a function to implement the io.Closer type.
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type CloserFunc func() error
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func (c CloserFunc) Close() error {
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return c()
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}
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// CloserCallback wraps io.Closer to add a callback deferred to call just after Close().
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func CloserCallback(c io.Closer, cb func()) io.Closer {
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return CloserFunc(func() error {
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defer cb()
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return c.Close()
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})
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}
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// CloserAfterCallback wraps io.Closer to add a callback called just before Close().
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func CloserAfterCallback(c io.Closer, cb func()) io.Closer {
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return CloserFunc(func() (err error) {
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defer func() { err = c.Close() }()
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cb()
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return
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})
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}
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// CloseOnce wraps an io.Closer to ensure it only performs the close logic once.
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func CloseOnce(c io.Closer) io.Closer {
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return CloserFunc(func() error {
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if c == nil {
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// already run.
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return nil
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}
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// Acquire.
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cptr := c
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c = nil
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// Call the closer.
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return cptr.Close()
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})
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}
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