3cea422365
Done with: ack '2021+' -l | xargs sed -i -e 's/2021+/2022+/g' Checked manually with: git add -p Hello to future James from 2023, and Happy Hacking!
86 lines
3.4 KiB
Go
86 lines
3.4 KiB
Go
// Mgmt
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// Copyright (C) 2013-2022+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU 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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// This program 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 General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package engine
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import (
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"fmt"
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)
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// ReversibleRes is an interface that a resource can implement if it wants to
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// have some resource run when it disappears. A disappearance happens when a
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// resource is defined in one instance of the graph, and is gone in the
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// subsequent one. This is helpful for building robust programs with the engine.
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// Default implementations for most of the methods declared in this interface
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// can be obtained for your resource by anonymously adding the traits.Reversible
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// struct to your resource implementation.
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type ReversibleRes interface {
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Res
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// ReversibleMeta lets you get or set meta params for the reversible
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// trait.
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ReversibleMeta() *ReversibleMeta
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// SetReversibleMeta lets you set all of the meta params for the
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// reversible trait in a single call.
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SetReversibleMeta(*ReversibleMeta)
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// Reversed returns the "reverse" or "reciprocal" resource. This is used
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// to "clean" up after a previously defined resource has been removed.
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// Interestingly, this could return the core Res interface instead of a
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// ReversibleRes, because there is no requirement that the reverse of a
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// Res be the same kind of Res, and the reverse might not be reversible!
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// However, in practice, it's nice to use some of the Reversible meta
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// params in the built value, so keep things simple and have this be a
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// reversible res. The Res itself doesn't have to implement Reversed()
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// in a meaningful way, it can just return nil and it will get ignored.
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Reversed() (ReversibleRes, error)
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}
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// ReversibleMeta provides some parameters specific to reversible resources.
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type ReversibleMeta struct {
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// Disabled specifies that reversing should be disabled for this
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// resource.
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Disabled bool
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// Reversal specifies that the resource was built from a reversal. This
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// must be set if the resource was built by a reversal.
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Reversal bool
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// Overwrite specifies that we should overwrite any existing stored
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// reversible resource if one that is pending already exists. If this is
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// false, and a resource with the same name and kind exists, then this
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// will cause an error.
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Overwrite bool
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// TODO: add options here, including whether to reverse edges, etc...
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}
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// Cmp compares two ReversibleMeta structs and determines if they're equivalent.
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func (obj *ReversibleMeta) Cmp(rm *ReversibleMeta) error {
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if obj.Disabled != rm.Disabled {
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return fmt.Errorf("values for Disabled are different")
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}
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if obj.Reversal != rm.Reversal { // TODO: do we want to compare these?
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return fmt.Errorf("values for Reversal are different")
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}
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if obj.Overwrite != rm.Overwrite {
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return fmt.Errorf("values for Overwrite are different")
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}
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return nil
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}
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