github.com/dolthub/dolt/go@v0.40.5-0.20240520175717-68db7794bea6/store/prolly/tree/node_builder.go (about)

     1  // Copyright 2022 Dolthub, Inc.
     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 tree
    16  
    17  import (
    18  	"context"
    19  	"sync"
    20  
    21  	"github.com/dolthub/dolt/go/store/prolly/message"
    22  
    23  	"github.com/dolthub/dolt/go/store/hash"
    24  )
    25  
    26  type novelNode struct {
    27  	node      Node
    28  	addr      hash.Hash
    29  	lastKey   Item
    30  	treeCount uint64
    31  }
    32  
    33  func writeNewNode[S message.Serializer](ctx context.Context, ns NodeStore, bld *nodeBuilder[S]) (novelNode, error) {
    34  	node, err := bld.build()
    35  	if err != nil {
    36  		return novelNode{}, err
    37  	}
    38  
    39  	addr, err := ns.Write(ctx, node)
    40  	if err != nil {
    41  		return novelNode{}, err
    42  	}
    43  
    44  	var lastKey Item
    45  	if node.count > 0 {
    46  		k := getLastKey(node)
    47  		lastKey = ns.Pool().Get(uint64(len(k)))
    48  		copy(lastKey, k)
    49  	}
    50  
    51  	cnt, err := node.TreeCount()
    52  	if err != nil {
    53  		return novelNode{}, err
    54  	}
    55  
    56  	return novelNode{
    57  		addr:      addr,
    58  		node:      node,
    59  		lastKey:   lastKey,
    60  		treeCount: uint64(cnt),
    61  	}, nil
    62  }
    63  
    64  func newNodeBuilder[S message.Serializer](serializer S, level int) (nb *nodeBuilder[S]) {
    65  	nb = &nodeBuilder[S]{
    66  		level:      level,
    67  		serializer: serializer,
    68  	}
    69  	return
    70  }
    71  
    72  type nodeBuilder[S message.Serializer] struct {
    73  	keys, values [][]byte
    74  	size, level  int
    75  	subtrees     subtreeCounts
    76  	serializer   S
    77  }
    78  
    79  func (nb *nodeBuilder[S]) hasCapacity(key, value Item) bool {
    80  	sum := nb.size + len(key) + len(value)
    81  	return sum <= int(message.MaxVectorOffset)
    82  }
    83  
    84  func (nb *nodeBuilder[S]) addItems(key, value Item, subtree uint64) {
    85  	if nb.keys == nil {
    86  		nb.keys = getItemSlices()
    87  		nb.values = getItemSlices()
    88  		nb.subtrees = getSubtreeSlice()
    89  	}
    90  	nb.keys = append(nb.keys, key)
    91  	nb.values = append(nb.values, value)
    92  	nb.size += len(key) + len(value)
    93  	nb.subtrees = append(nb.subtrees, subtree)
    94  }
    95  
    96  func (nb *nodeBuilder[S]) count() int {
    97  	return len(nb.keys)
    98  }
    99  
   100  func (nb *nodeBuilder[S]) build() (node Node, err error) {
   101  	msg := nb.serializer.Serialize(nb.keys, nb.values, nb.subtrees, nb.level)
   102  	nb.recycleBuffers()
   103  	nb.size = 0
   104  	return NodeFromBytes(msg)
   105  }
   106  
   107  func (nb *nodeBuilder[S]) recycleBuffers() {
   108  	putItemSlices(nb.keys[:0])
   109  	putItemSlices(nb.values[:0])
   110  	putSubtreeSlice(nb.subtrees[:0])
   111  	nb.keys = nil
   112  	nb.values = nil
   113  	nb.subtrees = nil
   114  }
   115  
   116  // todo(andy): replace with NodeStore.Pool()
   117  const nodeBuilderListSize = 256
   118  
   119  var itemsPool = sync.Pool{
   120  	New: func() any {
   121  		return make([][]byte, 0, nodeBuilderListSize)
   122  	},
   123  }
   124  
   125  func getItemSlices() [][]byte {
   126  	sl := itemsPool.Get().([][]byte)
   127  	return sl[:0]
   128  }
   129  
   130  func putItemSlices(sl [][]byte) {
   131  	itemsPool.Put(sl[:0])
   132  }
   133  
   134  var subtreePool = sync.Pool{
   135  	New: func() any {
   136  		return make([]uint64, 0, nodeBuilderListSize)
   137  	},
   138  }
   139  
   140  func getSubtreeSlice() []uint64 {
   141  	sl := subtreePool.Get().([]uint64)
   142  	return sl[:0]
   143  }
   144  
   145  func putSubtreeSlice(sl []uint64) {
   146  	subtreePool.Put(sl[:0])
   147  }