github.com/thanos-io/thanos@v0.32.5/pkg/errutil/multierror.go (about)

     1  // Copyright (c) The Thanos Authors.
     2  // Licensed under the Apache License 2.0.
     3  
     4  package errutil
     5  
     6  import (
     7  	"bytes"
     8  	"fmt"
     9  	"sync"
    10  )
    11  
    12  // The MultiError type implements the error interface, and contains the
    13  // Errors used to construct it.
    14  type MultiError []error
    15  
    16  // Add adds the error to the error list if it is not nil.
    17  func (es *MultiError) Add(err error) {
    18  	if err == nil {
    19  		return
    20  	}
    21  	if merr, ok := err.(NonNilMultiError); ok {
    22  		*es = append(*es, merr...)
    23  	} else {
    24  		*es = append(*es, err)
    25  	}
    26  }
    27  
    28  // Err returns the error list as an error or nil if it is empty.
    29  func (es MultiError) Err() error {
    30  	if len(es) == 0 {
    31  		return nil
    32  	}
    33  	return NonNilMultiError(es)
    34  }
    35  
    36  // SyncMultiError is a thread-safe implementation of MultiError.
    37  type SyncMultiError struct {
    38  	mtx sync.Mutex
    39  	es  MultiError
    40  }
    41  
    42  // Add adds the error to the error list if it is not nil.
    43  func (es *SyncMultiError) Add(err error) {
    44  	if err == nil {
    45  		return
    46  	}
    47  	es.mtx.Lock()
    48  	defer es.mtx.Unlock()
    49  
    50  	es.Add(err)
    51  }
    52  
    53  // Err returns the error list as an error or nil if it is empty.
    54  func (es *SyncMultiError) Err() error {
    55  	es.mtx.Lock()
    56  	defer es.mtx.Unlock()
    57  
    58  	return es.es.Err()
    59  }
    60  
    61  type NonNilMultiError MultiError
    62  
    63  // Returns a concatenated string of the contained errors.
    64  func (es NonNilMultiError) Error() string {
    65  	var buf bytes.Buffer
    66  
    67  	if len(es) > 1 {
    68  		fmt.Fprintf(&buf, "%d errors: ", len(es))
    69  	}
    70  
    71  	for i, err := range es {
    72  		if i != 0 {
    73  			buf.WriteString("; ")
    74  		}
    75  		buf.WriteString(err.Error())
    76  	}
    77  
    78  	return buf.String()
    79  }