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60 lines
1.0 KiB
Go
60 lines
1.0 KiB
Go
2 years ago
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package obspipeline
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import (
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"context"
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"fmt"
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)
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type State string
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type Event string
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type Action func(ctx context.Context) error
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type Node struct {
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State
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Transitions map[Event]*Transition
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}
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type Transition struct {
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*Node
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Action
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}
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type StateMachine struct {
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initialNode *Node
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CurrentNode *Node
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}
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func (m *StateMachine) getCurrentNode() *Node {
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return m.CurrentNode
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}
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func (m *StateMachine) getNextNode(event Event) (*Node, error) {
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if m.CurrentNode == nil {
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return nil, fmt.Errorf("nowhere to go anymore!\n")
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}
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transition, ok := m.CurrentNode.Transitions[event]
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if !ok {
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return nil, fmt.Errorf("invalid event: %v", event)
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}
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return transition.Node, nil
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}
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func (m *StateMachine) Transition(ctx context.Context, event Event) (*Node, error) {
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node, err := m.getNextNode(event) // gets current node
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if err != nil {
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return nil, fmt.Errorf(err.Error())
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}
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err = m.CurrentNode.Transitions[event].Action(ctx)
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if err != nil {
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return nil, fmt.Errorf(err.Error())
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}
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m.CurrentNode = node
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return m.CurrentNode, nil
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}
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