Files
mgmt/engine/reverse.go
James Shubin 07f542b4d7 legal: Happy 2019 everyone...
Done with:

ack '2018+' -l | xargs sed -i -e 's/2018+/2019+/g'

Checked manually with:

git add -p

Hello to future James from 2020, and Happy Hacking!
2019-03-24 15:08:50 -04:00

66 lines
2.5 KiB
Go

// Mgmt
// Copyright (C) 2013-2019+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package engine
import (
"fmt"
)
// ReversibleRes is an interface that a resource can implement if it wants to
// have some resource run when it disappears. A disappearance happens when a
// resource is defined in one instance of the graph, and is gone in the
// subsequent one. This is helpful for building robust programs with the engine.
// Default implementations for most of the methods declared in this interface
// can be obtained for your resource by anonymously adding the traits.Reversible
// struct to your resource implementation.
type ReversibleRes interface {
Res
// ReversibleMeta lets you get or set meta params for the reversible
// trait.
ReversibleMeta() *ReversibleMeta
// SetReversibleMeta lets you set all of the meta params for the
// reversible trait in a single call.
SetReversibleMeta(*ReversibleMeta)
// Reversed returns the "reverse" or "reciprocal" resource. This is used
// to "clean" up after a previously defined resource has been removed.
// Interestingly, this returns the core Res interface instead of a
// ReversibleRes, because there is no requirement that the reverse of a
// Res be the same kind of Res, and the reverse might not be reversible!
Reversed() (Res, error)
}
// ReversibleMeta provides some parameters specific to reversible resources.
type ReversibleMeta struct {
// Disabled specifies that reversing should be disabled for this
// resource.
Disabled bool
// TODO: add options here, including whether to reverse edges, etc...
}
// Cmp compares two ReversibleMeta structs and determines if they're equivalent.
func (obj *ReversibleMeta) Cmp(rm *ReversibleMeta) error {
if obj.Disabled != rm.Disabled {
return fmt.Errorf("values for Disabled are different")
}
return nil
}