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https://github.com/FlipsideCrypto/dcrd.git
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66010e4134
This modifies the ProcessBlock function in the blockchain package to return the fork length for the connected block and updates all callers and tests accordingly. Several of the internal functions which ProcessBlock calls are also updated in order to bubble the necessary information back up so it can be returned. It does not make any behavioral changes. This is being done to better expose information about the position of the block within the chain to callers without them having to make additional queries.
112 lines
4.0 KiB
Go
112 lines
4.0 KiB
Go
// Copyright (c) 2014-2016 The btcsuite developers
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// Copyright (c) 2015-2016 The Decred developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package blockchain_test
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import (
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"fmt"
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"math/big"
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"os"
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"path/filepath"
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"github.com/decred/dcrd/blockchain"
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"github.com/decred/dcrd/chaincfg"
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"github.com/decred/dcrd/database"
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_ "github.com/decred/dcrd/database/ffldb"
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"github.com/decred/dcrd/dcrutil"
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)
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// This example demonstrates how to create a new chain instance and use
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// ProcessBlock to attempt to attempt add a block to the chain. As the package
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// overview documentation describes, this includes all of the Decred consensus
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// rules. This example intentionally attempts to insert a duplicate genesis
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// block to illustrate how an invalid block is handled.
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func ExampleBlockChain_ProcessBlock() {
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// Create a new database to store the accepted blocks into. Typically
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// this would be opening an existing database and would not be deleting
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// and creating a new database like this, but it is done here so this is
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// a complete working example and does not leave temporary files laying
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// around.
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dbPath := filepath.Join(os.TempDir(), "exampleprocessblock")
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_ = os.RemoveAll(dbPath)
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db, err := database.Create("ffldb", dbPath, chaincfg.MainNetParams.Net)
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if err != nil {
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fmt.Printf("Failed to create database: %v\n", err)
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return
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}
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defer os.RemoveAll(dbPath)
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defer db.Close()
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// Create a new BlockChain instance using the underlying database for
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// the main bitcoin network. This example does not demonstrate some
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// of the other available configuration options such as specifying a
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// notification callback and signature cache. Also, the caller would
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// ordinarily keep a reference to the median time source and add time
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// values obtained from other peers on the network so the local time is
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// adjusted to be in agreement with other peers.
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chain, err := blockchain.New(&blockchain.Config{
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DB: db,
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ChainParams: &chaincfg.MainNetParams,
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TimeSource: blockchain.NewMedianTime(),
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})
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if err != nil {
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fmt.Printf("Failed to create chain instance: %v\n", err)
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return
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}
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// Process a block. For this example, we are going to intentionally
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// cause an error by trying to process the genesis block which already
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// exists.
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genesisBlock := dcrutil.NewBlock(chaincfg.MainNetParams.GenesisBlock)
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forkLen, isOrphan, err := chain.ProcessBlock(genesisBlock,
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blockchain.BFNone)
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if err != nil {
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fmt.Printf("Failed to create chain instance: %v\n", err)
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return
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}
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isMainChain := !isOrphan && forkLen == 0
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fmt.Printf("Block accepted. Is it on the main chain?: %v", isMainChain)
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fmt.Printf("Block accepted. Is it an orphan?: %v", isOrphan)
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// This output is dependent on the genesis block, and needs to be
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// updated if the mainnet genesis block is updated.
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// Output:
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// Failed to process block: already have block 267a53b5ee86c24a48ec37aee4f4e7c0c4004892b7259e695e9f5b321f1ab9d2
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}
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// This example demonstrates how to convert the compact "bits" in a block header
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// which represent the target difficulty to a big integer and display it using
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// the typical hex notation.
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func ExampleCompactToBig() {
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// Convert the bits from block 300000 in the main Decred block chain.
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bits := uint32(419465580)
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targetDifficulty := blockchain.CompactToBig(bits)
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// Display it in hex.
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fmt.Printf("%064x\n", targetDifficulty.Bytes())
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// Output:
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// 0000000000000000896c00000000000000000000000000000000000000000000
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}
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// This example demonstrates how to convert a target difficulty into the compact
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// "bits" in a block header which represent that target difficulty .
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func ExampleBigToCompact() {
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// Convert the target difficulty from block 300000 in the main block
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// chain to compact form.
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t := "0000000000000000896c00000000000000000000000000000000000000000000"
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targetDifficulty, success := new(big.Int).SetString(t, 16)
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if !success {
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fmt.Println("invalid target difficulty")
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return
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}
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bits := blockchain.BigToCompact(targetDifficulty)
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fmt.Println(bits)
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// Output:
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// 419465580
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}
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