77913ad2e8
This modifies the blockchain.ProcessBlock function to return an additional boolean as the first parameter which indicates whether or not the block ended up on the main chain. This is primarily useful for upcoming test code that needs to be able to tell the difference between a block accepted to a side chain and a block that either extends the main chain or causes a reorganize that causes it to become the main chain. However, it is also useful for the addblock utility since it allows a better error in the case a file with out of order blocks is provided.
108 lines
3.8 KiB
Go
108 lines
3.8 KiB
Go
// Copyright (c) 2014-2016 The btcsuite 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/btcsuite/btcd/blockchain"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/btcsuite/btcd/database"
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_ "github.com/btcsuite/btcd/database/ffldb"
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"github.com/btcsuite/btcutil"
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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 Bitcoin 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 := btcutil.NewBlock(chaincfg.MainNetParams.GenesisBlock)
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isMainChain, 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 process block: %v\n", err)
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return
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}
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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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// Output:
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// Failed to process block: already have block 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
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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 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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