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https://github.com/ethereum/go-ethereum.git
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1bccf4f2dd
## Why this should be merged The `temporary.WithTempRegisteredExtras()` global lock introduced in #234 wasn't fit for purpose when used in `coreth` as it required central coordination of registration, types, and usage of the payload accessor. ## How this works Instead of a central registration point, the new `libevm.WithTemporaryExtrasLock()` function takes out a global lock and provides the caller with a handle that proves the lock is held. All of the override functions, e.g. `params.WithTempRegisteredExtras()` now require a current lock, which will be propagated by the respective `coreth` functions. See https://github.com/ava-labs/coreth/pull/1328 for intended usage in `coreth` and `subnet-evm`. A consumer of both of these can then safely do the following: ```go import ( "github.com/ava-labs/libevm/libevm" coreth "github.com/ava-labs/coreth/plugin/evm" subnet "github.com/ava-labs/subnet-evm/plugin/evm" ) // asCChain calls `fn` while emulating `coreth`. It is safe for concurrent usage with [asSubnetEVM]. func asCChain(fn func() error) error { return libevm.WithTemporaryExtrasLock(func(l libevm.ExtrasLock) error { return coreth.WithTempRegisteredLibEVMExtras(l, fn) }) } // asSubnetEVM calls `fn` while emulating `subnet-evm`. It is safe for concurrent usage with [asCChain]. func asSubnetEVM(fn func() error) error { return libevm.WithTemporaryExtrasLock(func(l libevm.ExtrasLock) error { return subnet.WithTempRegisteredLibEVMExtras(l, fn) }) } ``` ## How this was tested Unit test of the new function plus existing integration tests of all modified code.
94 lines
2.7 KiB
Go
94 lines
2.7 KiB
Go
// Copyright 2024-2025 the libevm authors.
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//
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// The libevm additions to go-ethereum are free software: you can redistribute
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// them and/or modify them under the terms of the GNU Lesser General Public License
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// as published by the Free Software Foundation, either version 3 of the License,
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// or (at your option) any later version.
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//
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// The libevm additions are distributed in the hope that they 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 GNU Lesser
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// 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
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// <http://www.gnu.org/licenses/>.
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// Package register provides functionality for optional registration of types.
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package register
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import (
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"errors"
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"github.com/ava-labs/libevm/libevm/testonly"
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)
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// An AtMostOnce allows zero or one registration of a T.
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type AtMostOnce[T any] struct {
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v *T
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}
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// ErrReRegistration is returned on all but the first of calls to
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// [AtMostOnce.Register].
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var ErrReRegistration = errors.New("re-registration")
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// Register registers `v` or returns [ErrReRegistration] if already called.
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func (o *AtMostOnce[T]) Register(v T) error {
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if o.Registered() {
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return ErrReRegistration
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}
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o.v = &v
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return nil
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}
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// MustRegister is equivalent to [AtMostOnce.Register], panicking on error.
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func (o *AtMostOnce[T]) MustRegister(v T) {
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if err := o.Register(v); err != nil {
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panic(err)
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}
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}
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// Registered reports whether [AtMostOnce.Register] has been called.
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func (o *AtMostOnce[T]) Registered() bool {
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return o.v != nil
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}
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// Get returns the registered value. It MUST NOT be called before
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// [AtMostOnce.Register].
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func (o *AtMostOnce[T]) Get() T {
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return *o.v
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}
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// TestOnlyClear clears any previously registered value, returning `o` to its
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// default state. It panics if called from a non-testing call stack.
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func (o *AtMostOnce[T]) TestOnlyClear() {
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testonly.OrPanic(func() {
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o.v = nil
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})
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}
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// TempOverride calls `fn`, overriding any registered `T`, but only for the life
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// of the call. It is not threadsafe.
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//
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// It is valid to call this method with or without a prior call to
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// [AtMostOnce.Register].
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func (o *AtMostOnce[T]) TempOverride(with T, fn func() error) error {
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return o.temp(&with, fn)
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}
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// TempClear calls `fn`, clearing any registered `T`, but only for the life of
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// the call. It is not threadsafe.
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//
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// It is valid to call this method with or without a prior call to
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// [AtMostOnce.Register].
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func (o *AtMostOnce[T]) TempClear(fn func() error) error {
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return o.temp(nil, fn)
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}
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func (o *AtMostOnce[T]) temp(with *T, fn func() error) error {
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old := o.v
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o.v = with
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err := fn()
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o.v = old
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return err
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}
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