github.com/google/martian/v3@v3.3.3/multierror.go (about)

     1  // Copyright 2015 Google Inc. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package martian
    16  
    17  import (
    18  	"strings"
    19  	"sync"
    20  )
    21  
    22  // MultiError is a collection of errors that implements the error interface.
    23  type MultiError struct {
    24  	mu   sync.RWMutex
    25  	errs []error
    26  }
    27  
    28  // NewMultiError returns a new MultiError.
    29  func NewMultiError() *MultiError {
    30  	return &MultiError{}
    31  }
    32  
    33  // Error returns the list of errors separated by newlines.
    34  func (merr *MultiError) Error() string {
    35  	merr.mu.RLock()
    36  	defer merr.mu.RUnlock()
    37  
    38  	var errs []string
    39  	for _, err := range merr.errs {
    40  		errs = append(errs, err.Error())
    41  	}
    42  
    43  	return strings.Join(errs, "\n")
    44  }
    45  
    46  // Errors returns the error slice containing the error collection.
    47  func (merr *MultiError) Errors() []error {
    48  	merr.mu.RLock()
    49  	defer merr.mu.RUnlock()
    50  
    51  	return merr.errs
    52  }
    53  
    54  // Add appends an error to the error collection.
    55  func (merr *MultiError) Add(err error) {
    56  	merr.mu.Lock()
    57  	defer merr.mu.Unlock()
    58  
    59  	// Unwrap *MultiError to ensure that depth never exceeds 1.
    60  	if merr2, ok := err.(*MultiError); ok {
    61  		merr.errs = append(merr.errs, merr2.Errors()...)
    62  		return
    63  	}
    64  
    65  	merr.errs = append(merr.errs, err)
    66  }
    67  
    68  // Empty returns whether the *MultiError contains any errors.
    69  func (merr *MultiError) Empty() bool {
    70  	return len(merr.errs) == 0
    71  }