73 lines
2.5 KiB
Go
73 lines
2.5 KiB
Go
// Copyright 2017 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 tracers is a manager for transaction tracing engines.
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package tracers
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import (
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"encoding/json"
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"errors"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/vm"
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)
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// Context contains some contextual infos for a transaction execution that is not
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// available from within the EVM object.
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type Context struct {
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BlockHash common.Hash // Hash of the block the tx is contained within (zero if dangling tx or call)
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TxIndex int // Index of the transaction within a block (zero if dangling tx or call)
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TxHash common.Hash // Hash of the transaction being traced (zero if dangling call)
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}
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// Tracer interface extends vm.EVMLogger and additionally
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// allows collecting the tracing result.
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type Tracer interface {
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vm.EVMLogger
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GetResult() (json.RawMessage, error)
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// Stop terminates execution of the tracer at the first opportune moment.
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Stop(err error)
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}
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type lookupFunc func(string, *Context, json.RawMessage) (Tracer, error)
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var (
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lookups []lookupFunc
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)
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// RegisterLookup registers a method as a lookup for tracers, meaning that
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// users can invoke a named tracer through that lookup. If 'wildcard' is true,
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// then the lookup will be placed last. This is typically meant for interpreted
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// engines (js) which can evaluate dynamic user-supplied code.
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func RegisterLookup(wildcard bool, lookup lookupFunc) {
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if wildcard {
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lookups = append(lookups, lookup)
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} else {
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lookups = append([]lookupFunc{lookup}, lookups...)
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}
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}
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// New returns a new instance of a tracer, by iterating through the
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// registered lookups.
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func New(code string, ctx *Context, cfg json.RawMessage) (Tracer, error) {
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for _, lookup := range lookups {
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if tracer, err := lookup(code, ctx, cfg); err == nil {
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return tracer, nil
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}
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}
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return nil, errors.New("tracer not found")
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}
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