121 lines
2.9 KiB
Go
121 lines
2.9 KiB
Go
// Copyright 2015 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 core
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import (
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"sync"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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)
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// BlockCache implements a caching mechanism specifically for blocks and uses FILO to pop
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type BlockCache struct {
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size int
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hashes []common.Hash
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blocks map[common.Hash]*types.Block
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mu sync.RWMutex
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}
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// Creates and returns a `BlockCache` with `size`. If `size` is smaller than 1 it will panic
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func NewBlockCache(size int) *BlockCache {
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if size < 1 {
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panic("block cache size not allowed to be smaller than 1")
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}
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bc := &BlockCache{size: size}
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bc.Clear()
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return bc
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}
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func (bc *BlockCache) Clear() {
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bc.blocks = make(map[common.Hash]*types.Block)
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bc.hashes = nil
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}
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func (bc *BlockCache) Push(block *types.Block) {
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bc.mu.Lock()
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defer bc.mu.Unlock()
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if len(bc.hashes) == bc.size {
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delete(bc.blocks, bc.hashes[0])
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// XXX There are a few other options on solving this
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// 1) use a poller / GC like mechanism to clean up untracked objects
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// 2) copy as below
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// re-use the slice and remove the reference to bc.hashes[0]
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// this will allow the element to be garbage collected.
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copy(bc.hashes, bc.hashes[1:])
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} else {
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bc.hashes = append(bc.hashes, common.Hash{})
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}
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hash := block.Hash()
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bc.blocks[hash] = block
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bc.hashes[len(bc.hashes)-1] = hash
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}
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func (bc *BlockCache) Delete(hash common.Hash) {
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bc.mu.Lock()
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defer bc.mu.Unlock()
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if _, ok := bc.blocks[hash]; ok {
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delete(bc.blocks, hash)
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for i, h := range bc.hashes {
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if hash == h {
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bc.hashes = bc.hashes[:i+copy(bc.hashes[i:], bc.hashes[i+1:])]
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// or ? => bc.hashes = append(bc.hashes[:i], bc.hashes[i+1]...)
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break
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}
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}
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}
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}
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func (bc *BlockCache) Get(hash common.Hash) *types.Block {
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bc.mu.RLock()
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defer bc.mu.RUnlock()
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if block, haz := bc.blocks[hash]; haz {
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return block
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}
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return nil
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}
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func (bc *BlockCache) Has(hash common.Hash) bool {
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bc.mu.RLock()
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defer bc.mu.RUnlock()
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_, ok := bc.blocks[hash]
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return ok
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}
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func (bc *BlockCache) Each(cb func(int, *types.Block)) {
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bc.mu.Lock()
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defer bc.mu.Unlock()
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i := 0
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for _, block := range bc.blocks {
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cb(i, block)
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i++
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}
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}
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