github.com/ledgerwatch/erigon-lib@v1.0.0/kv/iter/helpers.go (about)

     1  /*
     2     Copyright 2021 Erigon contributors
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package iter
    18  
    19  import (
    20  	"fmt"
    21  	"testing"
    22  
    23  	"github.com/stretchr/testify/require"
    24  )
    25  
    26  func ToArr[T any](s Unary[T]) (res []T, err error) {
    27  	for s.HasNext() {
    28  		k, err := s.Next()
    29  		if err != nil {
    30  			return res, err
    31  		}
    32  		res = append(res, k)
    33  	}
    34  	return res, nil
    35  }
    36  
    37  func ToDualArray[K, V any](s Dual[K, V]) (keys []K, values []V, err error) {
    38  	for s.HasNext() {
    39  		k, v, err := s.Next()
    40  		if err != nil {
    41  			return keys, values, err
    42  		}
    43  		keys = append(keys, k)
    44  		values = append(values, v)
    45  	}
    46  	return keys, values, nil
    47  }
    48  
    49  func ExpectEqualU64(tb testing.TB, s1, s2 Unary[uint64]) {
    50  	tb.Helper()
    51  	ExpectEqual[uint64](tb, s1, s2)
    52  }
    53  func ExpectEqual[V comparable](tb testing.TB, s1, s2 Unary[V]) {
    54  	tb.Helper()
    55  	for s1.HasNext() && s2.HasNext() {
    56  		k1, e1 := s1.Next()
    57  		k2, e2 := s2.Next()
    58  		require.Equal(tb, e1 == nil, e2 == nil)
    59  		require.Equal(tb, k1, k2)
    60  	}
    61  
    62  	has1 := s1.HasNext()
    63  	has2 := s2.HasNext()
    64  	var label string
    65  	if has1 {
    66  		v1, _ := s1.Next()
    67  		label = fmt.Sprintf("v1: %v", v1)
    68  	}
    69  	if has2 {
    70  		v2, _ := s2.Next()
    71  		label += fmt.Sprintf(" v2: %v", v2)
    72  	}
    73  	require.False(tb, has1, label)
    74  	require.False(tb, has2, label)
    75  }
    76  
    77  // PairsWithErrorIter - return N, keys and then error
    78  type PairsWithErrorIter struct {
    79  	errorAt, i int
    80  }
    81  
    82  func PairsWithError(errorAt int) *PairsWithErrorIter {
    83  	return &PairsWithErrorIter{errorAt: errorAt}
    84  }
    85  func (m *PairsWithErrorIter) HasNext() bool { return true }
    86  func (m *PairsWithErrorIter) Next() ([]byte, []byte, error) {
    87  	if m.i >= m.errorAt {
    88  		return nil, nil, fmt.Errorf("expected error at iteration: %d", m.errorAt)
    89  	}
    90  	m.i++
    91  	return []byte(fmt.Sprintf("%x", m.i)), []byte(fmt.Sprintf("%x", m.i)), nil
    92  }
    93  
    94  func Count[T any](s Unary[T]) (cnt int, err error) {
    95  	for s.HasNext() {
    96  		_, err := s.Next()
    97  		if err != nil {
    98  			return cnt, err
    99  		}
   100  		cnt++
   101  	}
   102  	return cnt, err
   103  }
   104  
   105  func CountDual[K, V any](s Dual[K, V]) (cnt int, err error) {
   106  	for s.HasNext() {
   107  		_, _, err := s.Next()
   108  		if err != nil {
   109  			return cnt, err
   110  		}
   111  		cnt++
   112  	}
   113  	return cnt, err
   114  }