gtsocial-umbx

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close.go (795B)

      1 package iotools
      2 
      3 import "io"
      4 
      5 // CloserFunc is a function signature which allows
      6 // a function to implement the io.Closer type.
      7 type CloserFunc func() error
      8 
      9 func (c CloserFunc) Close() error {
     10 	return c()
     11 }
     12 
     13 func CloserCallback(c io.Closer, cb func()) io.Closer {
     14 	return CloserFunc(func() error {
     15 		defer cb()
     16 		return c.Close()
     17 	})
     18 }
     19 
     20 func CloserAfterCallback(c io.Closer, cb func()) io.Closer {
     21 	return CloserFunc(func() (err error) {
     22 		defer func() { err = c.Close() }()
     23 		cb()
     24 		return
     25 	})
     26 }
     27 
     28 // CloseOnce wraps an io.Closer to ensure it only performs the close logic once.
     29 func CloseOnce(c io.Closer) io.Closer {
     30 	return CloserFunc(func() error {
     31 		if c == nil {
     32 			// already run.
     33 			return nil
     34 		}
     35 
     36 		// Acquire.
     37 		cptr := c
     38 		c = nil
     39 
     40 		// Call the closer.
     41 		return cptr.Close()
     42 	})
     43 }