tendermint/merkle/iavl_tree.go

package merkle

import (
    . "github.com/tendermint/tendermint/binary"
)

const HASH_BYTE_SIZE int = 4+32

/*
Immutable AVL Tree (wraps the Node root)

This tree is not concurrency safe.
You must wrap your calls with your own mutex.
*/
type IAVLTree struct {
    db      Db
    root    *IAVLNode
}

func NewIAVLTree(db Db) *IAVLTree {
    return &IAVLTree{db:db, root:nil}
}

func NewIAVLTreeFromHash(db Db, hash ByteSlice) *IAVLTree {
    root := &IAVLNode{
        hash:   hash,
        flags:  IAVLNODE_FLAG_PERSISTED | IAVLNODE_FLAG_PLACEHOLDER,
    }
    root.fill(db)
    return &IAVLTree{db:db, root:root}
}

func (t *IAVLTree) Root() Node {
    return t.root
}

func (t *IAVLTree) Size() uint64 {
    if t.root == nil { return 0 }
    return t.root.Size()
}

func (t *IAVLTree) Height() uint8 {
    if t.root == nil { return 0 }
    return t.root.Height()
}

func (t *IAVLTree) Has(key Key) bool {
    if t.root == nil { return false }
    return t.root.has(t.db, key)
}

func (t *IAVLTree) Put(key Key, value Value) (updated bool) {
    if t.root == nil {
        t.root = NewIAVLNode(key, value)
        return false
    }
    t.root, updated = t.root.put(t.db, key, value)
    return updated
}

func (t *IAVLTree) Hash() (ByteSlice, uint64) {
    if t.root == nil { return nil, 0 }
    return t.root.Hash()
}

func (t *IAVLTree) Save() {
    if t.root == nil { return }
    if t.root.hash == nil {
        t.root.Hash()
    }
    t.root.Save(t.db)
}

func (t *IAVLTree) Get(key Key) (value Value) {
    if t.root == nil { return nil }
    return t.root.get(t.db, key)
}

func (t *IAVLTree) Remove(key Key) (value Value, err error) {
    if t.root == nil { return nil, NotFound(key) }
    newRoot, _, value, err := t.root.remove(t.db, key)
    if err != nil {
        return nil, err
    }
    t.root = newRoot
    return value, nil
}

func (t *IAVLTree) Copy() Tree {
    return &IAVLTree{db:t.db, root:t.root}
}

// Traverses all the nodes of the tree in prefix order.
// return true from cb to halt iteration.
// node.Height() == 0 if you just want a value node.
func (t *IAVLTree) Traverse(cb func(Node) bool) {
    if t.root == nil { return }
    t.root.traverse(t.db, cb)
}

func (t *IAVLTree) Values() <-chan Value {
    root := t.root
    ch := make(chan Value)
    go func() {
        root.traverse(t.db, func(n Node) bool {
            if n.Height() == 0 { ch <- n.Value() }
            return true
        })
        close(ch)
    }()
    return ch
}