235 lines
7.3 KiB
Go
235 lines
7.3 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package trie
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import (
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"fmt"
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"github.com/ethereum/go-ethereum/common"
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)
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// leaf represents a trie leaf node
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type leaf struct {
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blob []byte // raw blob of leaf
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parent common.Hash // the hash of parent node
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}
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// committer is the tool used for the trie Commit operation. The committer will
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// capture all dirty nodes during the commit process and keep them cached in
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// insertion order.
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type committer struct {
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nodes *NodeSet
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tracer *tracer
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collectLeaf bool
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}
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// newCommitter creates a new committer or picks one from the pool.
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func newCommitter(owner common.Hash, tracer *tracer, collectLeaf bool) *committer {
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return &committer{
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nodes: NewNodeSet(owner),
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tracer: tracer,
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collectLeaf: collectLeaf,
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}
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}
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// Commit collapses a node down into a hash node and returns it along with
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// the modified nodeset.
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func (c *committer) Commit(n node) (hashNode, *NodeSet, error) {
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h, err := c.commit(nil, n)
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if err != nil {
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return nil, nil, err
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}
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// Some nodes can be deleted from trie which can't be captured by committer
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// itself. Iterate all deleted nodes tracked by tracer and marked them as
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// deleted only if they are present in database previously.
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for _, path := range c.tracer.deleteList() {
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// There are a few possibilities for this scenario(the node is deleted
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// but not present in database previously), for example the node was
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// embedded in the parent and now deleted from the trie. In this case
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// it's noop from database's perspective.
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val := c.tracer.getPrev(path)
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if len(val) == 0 {
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continue
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}
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c.nodes.markDeleted(path, val)
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}
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return h.(hashNode), c.nodes, nil
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}
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// commit collapses a node down into a hash node and returns it.
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func (c *committer) commit(path []byte, n node) (node, error) {
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// if this path is clean, use available cached data
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hash, dirty := n.cache()
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if hash != nil && !dirty {
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return hash, nil
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}
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// Commit children, then parent, and remove the dirty flag.
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switch cn := n.(type) {
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case *shortNode:
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// Commit child
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collapsed := cn.copy()
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// If the child is fullNode, recursively commit,
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// otherwise it can only be hashNode or valueNode.
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if _, ok := cn.Val.(*fullNode); ok {
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childV, err := c.commit(append(path, cn.Key...), cn.Val)
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if err != nil {
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return nil, err
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}
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collapsed.Val = childV
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}
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// The key needs to be copied, since we're adding it to the
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// modified nodeset.
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collapsed.Key = hexToCompact(cn.Key)
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hashedNode := c.store(path, collapsed)
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if hn, ok := hashedNode.(hashNode); ok {
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return hn, nil
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}
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// The short node now is embedded in its parent. Mark the node as
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// deleted if it's present in database previously. It's equivalent
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// as deletion from database's perspective.
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if prev := c.tracer.getPrev(path); len(prev) != 0 {
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c.nodes.markDeleted(path, prev)
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}
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return collapsed, nil
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case *fullNode:
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hashedKids, err := c.commitChildren(path, cn)
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if err != nil {
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return nil, err
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}
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collapsed := cn.copy()
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collapsed.Children = hashedKids
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hashedNode := c.store(path, collapsed)
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if hn, ok := hashedNode.(hashNode); ok {
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return hn, nil
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}
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// The full node now is embedded in its parent. Mark the node as
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// deleted if it's present in database previously. It's equivalent
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// as deletion from database's perspective.
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if prev := c.tracer.getPrev(path); len(prev) != 0 {
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c.nodes.markDeleted(path, prev)
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}
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return collapsed, nil
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case hashNode:
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return cn, nil
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default:
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// nil, valuenode shouldn't be committed
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panic(fmt.Sprintf("%T: invalid node: %v", n, n))
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}
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}
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// commitChildren commits the children of the given fullnode
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func (c *committer) commitChildren(path []byte, n *fullNode) ([17]node, error) {
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var children [17]node
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for i := 0; i < 16; i++ {
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child := n.Children[i]
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if child == nil {
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continue
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}
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// If it's the hashed child, save the hash value directly.
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// Note: it's impossible that the child in range [0, 15]
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// is a valueNode.
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if hn, ok := child.(hashNode); ok {
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children[i] = hn
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continue
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}
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// Commit the child recursively and store the "hashed" value.
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// Note the returned node can be some embedded nodes, so it's
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// possible the type is not hashNode.
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hashed, err := c.commit(append(path, byte(i)), child)
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if err != nil {
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return children, err
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}
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children[i] = hashed
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}
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// For the 17th child, it's possible the type is valuenode.
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if n.Children[16] != nil {
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children[16] = n.Children[16]
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}
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return children, nil
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}
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// store hashes the node n and adds it to the modified nodeset. If leaf collection
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// is enabled, leaf nodes will be tracked in the modified nodeset as well.
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func (c *committer) store(path []byte, n node) node {
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// Larger nodes are replaced by their hash and stored in the database.
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var hash, _ = n.cache()
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// This was not generated - must be a small node stored in the parent.
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// In theory, we should check if the node is leaf here (embedded node
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// usually is leaf node). But small value (less than 32bytes) is not
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// our target (leaves in account trie only).
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if hash == nil {
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return n
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}
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// We have the hash already, estimate the RLP encoding-size of the node.
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// The size is used for mem tracking, does not need to be exact
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var (
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size = estimateSize(n)
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nhash = common.BytesToHash(hash)
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mnode = &memoryNode{
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hash: nhash,
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node: simplifyNode(n),
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size: uint16(size),
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}
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)
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// Collect the dirty node to nodeset for return.
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c.nodes.markUpdated(path, mnode, c.tracer.getPrev(path))
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// Collect the corresponding leaf node if it's required. We don't check
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// full node since it's impossible to store value in fullNode. The key
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// length of leaves should be exactly same.
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if c.collectLeaf {
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if sn, ok := n.(*shortNode); ok {
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if val, ok := sn.Val.(valueNode); ok {
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c.nodes.addLeaf(&leaf{blob: val, parent: nhash})
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}
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}
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}
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return hash
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}
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// estimateSize estimates the size of an rlp-encoded node, without actually
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// rlp-encoding it (zero allocs). This method has been experimentally tried, and with a trie
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// with 1000 leaves, the only errors above 1% are on small shortnodes, where this
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// method overestimates by 2 or 3 bytes (e.g. 37 instead of 35)
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func estimateSize(n node) int {
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switch n := n.(type) {
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case *shortNode:
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// A short node contains a compacted key, and a value.
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return 3 + len(n.Key) + estimateSize(n.Val)
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case *fullNode:
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// A full node contains up to 16 hashes (some nils), and a key
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s := 3
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for i := 0; i < 16; i++ {
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if child := n.Children[i]; child != nil {
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s += estimateSize(child)
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} else {
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s++
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}
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}
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return s
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case valueNode:
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return 1 + len(n)
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case hashNode:
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return 1 + len(n)
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default:
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panic(fmt.Sprintf("node type %T", n))
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}
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}
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