253ed78cc6
The engine core had some unfortunate bugs that were the result of some early design errors when I wasn't as familiar with channels. I've finally rewritten most of the bad parts, and I think it's much more logical and stable now. This also simplifies the resource API, since more of the work is done completely in the engine, and hidden from view. Lastly, this adds a few new metaparameters and associated code. There are still some open problems left to solve, but hopefully this brings us one step closer.
66 lines
2.5 KiB
Go
66 lines
2.5 KiB
Go
// Mgmt
|
|
// Copyright (C) 2013-2018+ 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
|
|
}
|