github.com/matrixorigin/matrixone@v0.7.0/pkg/txn/storage/memorystorage/memorytable/btree.go (about)

     1  // Copyright 2022 Matrix Origin
     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 memorytable
    16  
    17  import (
    18  	"bytes"
    19  	"encoding"
    20  	"encoding/gob"
    21  	"errors"
    22  	"io"
    23  
    24  	"github.com/tidwall/btree"
    25  )
    26  
    27  type BTree[
    28  	K Ordered[K],
    29  	V any,
    30  ] struct {
    31  	rows *btree.BTreeG[TreeNode[K, V]]
    32  }
    33  
    34  func NewBTree[
    35  	K Ordered[K],
    36  	V any,
    37  ]() *BTree[K, V] {
    38  	return &BTree[K, V]{
    39  		rows: btree.NewBTreeG(compareTreeNode[K, V]),
    40  	}
    41  }
    42  
    43  var _ Tree[Int, int] = new(BTree[Int, int])
    44  
    45  func (b *BTree[K, V]) Copy() Tree[K, V] {
    46  	return &BTree[K, V]{
    47  		rows: b.rows.Copy(),
    48  	}
    49  }
    50  
    51  func (b *BTree[K, V]) Get(pivot TreeNode[K, V]) (TreeNode[K, V], bool) {
    52  	return b.rows.Get(pivot)
    53  }
    54  
    55  func (b *BTree[K, V]) Set(pair TreeNode[K, V]) (TreeNode[K, V], bool) {
    56  	return b.rows.Set(pair)
    57  }
    58  
    59  func (b *BTree[K, V]) Delete(pivot TreeNode[K, V]) {
    60  	b.rows.Delete(pivot)
    61  }
    62  
    63  type btreeKVIter[
    64  	K Ordered[K],
    65  	V any,
    66  ] struct {
    67  	iter btree.GenericIter[TreeNode[K, V]]
    68  }
    69  
    70  func (b *BTree[K, V]) Iter() TreeIter[K, V] {
    71  	iter := b.rows.Iter()
    72  	return &btreeKVIter[K, V]{
    73  		iter: iter,
    74  	}
    75  }
    76  
    77  func (b *btreeKVIter[K, V]) Close() error {
    78  	b.iter.Release()
    79  	return nil
    80  }
    81  
    82  func (b *btreeKVIter[K, V]) First() bool {
    83  	return b.iter.First()
    84  }
    85  
    86  func (b *btreeKVIter[K, V]) Next() bool {
    87  	return b.iter.Next()
    88  }
    89  
    90  func (b *btreeKVIter[K, V]) Read() (TreeNode[K, V], error) {
    91  	return b.iter.Item(), nil
    92  }
    93  
    94  func (b *btreeKVIter[K, V]) Seek(pivot TreeNode[K, V]) bool {
    95  	return b.iter.Seek(pivot)
    96  }
    97  
    98  var _ encoding.BinaryMarshaler = new(BTree[Int, int])
    99  
   100  func (b *BTree[K, V]) MarshalBinary() ([]byte, error) {
   101  	gobRegister(b)
   102  	buf := new(bytes.Buffer)
   103  	encoder := gob.NewEncoder(buf)
   104  	iter := b.rows.Copy().Iter()
   105  	defer iter.Release()
   106  	for ok := iter.First(); ok; ok = iter.Next() {
   107  		pair := iter.Item()
   108  		if err := encoder.Encode(pair); err != nil {
   109  			return nil, err
   110  		}
   111  	}
   112  	return buf.Bytes(), nil
   113  }
   114  
   115  var _ encoding.BinaryUnmarshaler = new(BTree[Int, int])
   116  
   117  func (b *BTree[K, V]) UnmarshalBinary(data []byte) error {
   118  	gobRegister(b)
   119  	rows := b.rows
   120  	if rows == nil {
   121  		rows = btree.NewBTreeG(compareTreeNode[K, V])
   122  	}
   123  	decoder := gob.NewDecoder(bytes.NewReader(data))
   124  	for {
   125  		var node TreeNode[K, V]
   126  		err := decoder.Decode(&node)
   127  		if err != nil {
   128  			if errors.Is(err, io.EOF) {
   129  				break
   130  			}
   131  			return err
   132  		}
   133  		rows.Set(node)
   134  	}
   135  	b.rows = rows
   136  	return nil
   137  }