b134c4b778
This removes the `Close() error` and replaces it with a more modern Stream API that takes a context. This removes boilerplate and makes integration with concurrent code easier. The only downside is that there isn't an explicit cleanup step, but only one function was even using that and it was possible to switch it to a defer in Stream. This also renames the functions from polyfunc to just func which we determine by API not naming.
87 lines
2.4 KiB
Go
87 lines
2.4 KiB
Go
// Mgmt
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// Copyright (C) 2013-2023+ 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 structs
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import (
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"context"
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"fmt"
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"github.com/purpleidea/mgmt/lang/interfaces"
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"github.com/purpleidea/mgmt/lang/types"
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)
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const (
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// ConstFuncName is the unique name identifier for this function.
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ConstFuncName = "const"
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)
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// ConstFunc is a function that returns the constant value passed to Value.
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type ConstFunc struct {
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Value types.Value
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init *interfaces.Init
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}
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// String returns a simple name for this function. This is needed so this struct
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// can satisfy the pgraph.Vertex interface.
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func (obj *ConstFunc) String() string {
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return ConstFuncName
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}
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// Validate makes sure we've built our struct properly.
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func (obj *ConstFunc) Validate() error {
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if obj.Value == nil {
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return fmt.Errorf("must specify `Value` input")
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}
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return nil
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}
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// Info returns some static info about itself.
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func (obj *ConstFunc) Info() *interfaces.Info {
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var typ *types.Type
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if obj.Value != nil { // don't panic if called speculatively
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if t := obj.Value.Type(); t != nil {
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typ = types.NewType(fmt.Sprintf("func() %s", t.String()))
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}
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}
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return &interfaces.Info{
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Pure: true,
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Memo: false, // TODO: ???
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Sig: typ,
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Err: obj.Validate(), // XXX: implement this and check .Err in engine!
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}
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}
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// Init runs some startup code for this const.
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func (obj *ConstFunc) Init(init *interfaces.Init) error {
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obj.init = init
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return nil
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}
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// Stream returns the single value that this const has, and then closes.
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func (obj *ConstFunc) Stream(ctx context.Context) error {
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select {
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case obj.init.Output <- obj.Value:
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// pass
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case <-ctx.Done():
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return nil
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}
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close(obj.init.Output) // signal that we're done sending
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return nil
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}
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