112 lines
3.5 KiB
Go
112 lines
3.5 KiB
Go
// Copyright (c) 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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/*
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Package indexers implements optional block chain indexes.
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*/
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package indexers
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import (
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"encoding/binary"
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"errors"
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"github.com/lbryio/lbcd/blockchain"
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"github.com/lbryio/lbcd/database"
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btcutil "github.com/lbryio/lbcutil"
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)
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var (
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// byteOrder is the preferred byte order used for serializing numeric
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// fields for storage in the database.
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byteOrder = binary.LittleEndian
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// errInterruptRequested indicates that an operation was cancelled due
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// to a user-requested interrupt.
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errInterruptRequested = errors.New("interrupt requested")
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)
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// NeedsInputser provides a generic interface for an indexer to specify the it
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// requires the ability to look up inputs for a transaction.
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type NeedsInputser interface {
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NeedsInputs() bool
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}
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// Indexer provides a generic interface for an indexer that is managed by an
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// index manager such as the Manager type provided by this package.
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type Indexer interface {
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// Key returns the key of the index as a byte slice.
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Key() []byte
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// Name returns the human-readable name of the index.
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Name() string
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// Create is invoked when the indexer manager determines the index needs
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// to be created for the first time.
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Create(dbTx database.Tx) error
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// Init is invoked when the index manager is first initializing the
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// index. This differs from the Create method in that it is called on
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// every load, including the case the index was just created.
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Init() error
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// ConnectBlock is invoked when a new block has been connected to the
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// main chain. The set of output spent within a block is also passed in
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// so indexers can access the pevious output scripts input spent if
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// required.
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ConnectBlock(database.Tx, *btcutil.Block, []blockchain.SpentTxOut) error
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// DisconnectBlock is invoked when a block has been disconnected from
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// the main chain. The set of outputs scripts that were spent within
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// this block is also returned so indexers can clean up the prior index
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// state for this block
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DisconnectBlock(database.Tx, *btcutil.Block, []blockchain.SpentTxOut) error
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}
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// AssertError identifies an error that indicates an internal code consistency
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// issue and should be treated as a critical and unrecoverable error.
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type AssertError string
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// Error returns the assertion error as a huma-readable string and satisfies
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// the error interface.
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func (e AssertError) Error() string {
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return "assertion failed: " + string(e)
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}
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// errDeserialize signifies that a problem was encountered when deserializing
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// data.
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type errDeserialize string
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// Error implements the error interface.
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func (e errDeserialize) Error() string {
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return string(e)
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}
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// isDeserializeErr returns whether or not the passed error is an errDeserialize
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// error.
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func isDeserializeErr(err error) bool {
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_, ok := err.(errDeserialize)
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return ok
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}
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// internalBucket is an abstraction over a database bucket. It is used to make
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// the code easier to test since it allows mock objects in the tests to only
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// implement these functions instead of everything a database.Bucket supports.
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type internalBucket interface {
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Get(key []byte) []byte
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Put(key []byte, value []byte) error
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Delete(key []byte) error
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}
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// interruptRequested returns true when the provided channel has been closed.
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// This simplifies early shutdown slightly since the caller can just use an if
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// statement instead of a select.
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func interruptRequested(interrupted <-chan struct{}) bool {
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select {
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case <-interrupted:
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return true
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default:
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}
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return false
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}
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