storage/boltz/tx_context.go

/*
	Copyright NetFoundry, Inc.

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	https://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
*/

package boltz

import (
	"context"
	"go.etcd.io/bbolt"
)

type CommitAction interface {
	Exec()
}

type MutateContext interface {
	Tx() *bbolt.Tx
	AddPreCommitAction(func(ctx MutateContext) error)
	runPreCommitActions() error
	AddCommitAction(func())
	setTx(tx *bbolt.Tx) MutateContext
	IsSystemContext() bool
	GetSystemContext() MutateContext
	Context() context.Context
	UpdateContext(func(ctx context.Context) context.Context) MutateContext
}

func NewMutateContext(context context.Context) MutateContext {
	ctx := &mutateContext{
		ctx: context,
	}
	return ctx
}

func NewTxMutateContext(context context.Context, tx *bbolt.Tx) MutateContext {
	ctx := &mutateContext{
		ctx: context,
	}
	ctx.setTx(tx)
	return ctx
}

type mutateContext struct {
	tx               *bbolt.Tx
	ctx              context.Context
	preCommitActions []func(MutateContext) error
	commitActions    []func()
}

func (self *mutateContext) GetSystemContext() MutateContext {
	return NewSystemMutateContext(self)
}

func (self *mutateContext) IsSystemContext() bool {
	return false
}

func (self *mutateContext) Tx() *bbolt.Tx {
	return self.tx
}

func (self *mutateContext) setTx(tx *bbolt.Tx) MutateContext {
	self.tx = tx
	if tx != nil {
		tx.OnCommit(self.handleCommit)
	}
	return self
}

func (self *mutateContext) AddCommitAction(f func()) {
	self.commitActions = append(self.commitActions, f)
}

func (self *mutateContext) AddPreCommitAction(f func(MutateContext) error) {
	self.preCommitActions = append(self.preCommitActions, f)
}

func (self *mutateContext) runPreCommitActions() error {
	for _, action := range self.preCommitActions {
		if err := action(self); err != nil {
			return err
		}
	}
	return nil
}

func (self *mutateContext) handleCommit() {
	go func() {
		for _, hook := range self.commitActions {
			hook()
		}
	}()
}

func (self *mutateContext) Context() context.Context {
	return self.ctx
}

func (self *mutateContext) UpdateContext(f func(context.Context) context.Context) MutateContext {
	self.ctx = f(self.ctx)
	return self
}

func NewSystemMutateContext(ctx MutateContext) MutateContext {
	if ctx.IsSystemContext() {
		return ctx
	}
	return &systemMutateContext{
		wrapped: ctx,
	}
}

type systemMutateContext struct {
	wrapped MutateContext
}

func (self *systemMutateContext) AddPreCommitAction(f func(MutateContext) error) {
	self.wrapped.AddPreCommitAction(f)
}

func (self *systemMutateContext) AddCommitAction(f func()) {
	self.wrapped.AddCommitAction(f)
}

func (self *systemMutateContext) runPreCommitActions() error {
	return self.wrapped.runPreCommitActions()
}

func (self *systemMutateContext) GetSystemContext() MutateContext {
	return self
}

func (self *systemMutateContext) Tx() *bbolt.Tx {
	return self.wrapped.Tx()
}

func (self *systemMutateContext) setTx(tx *bbolt.Tx) MutateContext {
	return self.wrapped.setTx(tx)
}

func (self *systemMutateContext) IsSystemContext() bool {
	return true
}

func (self *systemMutateContext) Context() context.Context {
	return self.wrapped.Context()
}

func (self *systemMutateContext) UpdateContext(f func(context.Context) context.Context) MutateContext {
	return self.wrapped.UpdateContext(f)
}