127 lines
2.9 KiB
Go
127 lines
2.9 KiB
Go
package main
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import (
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"log"
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"sync"
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"github.com/google/uuid"
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)
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// Generate a random graphql id
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func randid() string{
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uuid_str := uuid.New().String()
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return uuid_str
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}
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type GraphSignal interface {
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Source() GraphNode
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Type() string
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Description() string
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}
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type BaseSignal struct {
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source GraphNode
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signal_type string
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description string
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}
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func (signal BaseSignal) Source() GraphNode {
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return signal.source
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}
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func (signal BaseSignal) Type() string {
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return signal.signal_type
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}
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func (signal BaseSignal) Description() string {
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return signal.description
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}
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func NewSignal(source GraphNode, signal_type string) (BaseSignal) {
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signal := BaseSignal{
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source: source,
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signal_type: signal_type,
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}
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return signal
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}
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// GraphNode is the interface common to both DAG nodes and Event tree nodes
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type GraphNode interface {
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Name() string
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Description() string
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ID() string
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Update(update GraphSignal) error
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RegisterChannel(listener chan GraphSignal)
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UnregisterChannel(listener chan GraphSignal)
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UpdateChannel() chan GraphSignal
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}
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// BaseNode is the most basic implementation of the GraphNode interface
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// It is used to implement functions common to Events and Resources
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type BaseNode struct {
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name string
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description string
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id string
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signal chan GraphSignal
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listeners_lock sync.Mutex
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listeners map[chan GraphSignal]chan GraphSignal
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}
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func (node * BaseNode) Name() string {
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return node.name
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}
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func (node * BaseNode) Description() string {
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return node.description
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}
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func (node * BaseNode) ID() string {
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return node.id
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}
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// Create a new listener channel for the node, add it to the nodes listener list, and return the new channel
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const listener_buffer = 10
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func (node * BaseNode) UpdateChannel() chan GraphSignal {
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new_listener := make(chan GraphSignal, listener_buffer)
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node.RegisterChannel(new_listener)
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return new_listener
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}
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func (node * BaseNode) RegisterChannel(listener chan GraphSignal) {
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node.listeners_lock.Lock()
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_, exists := node.listeners[listener]
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if exists == false {
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node.listeners[listener] = listener
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}
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node.listeners_lock.Unlock()
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}
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func (node * BaseNode) UnregisterChannel(listener chan GraphSignal) {
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node.listeners_lock.Lock()
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_, exists := node.listeners[listener]
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if exists == false {
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panic("Attempting to unregister non-registered listener")
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} else {
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delete(node.listeners, listener)
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}
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node.listeners_lock.Unlock()
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}
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// Send the update to listener channels
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func (node * BaseNode) UpdateListeners(update GraphSignal) {
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node.listeners_lock.Lock()
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for _, listener := range node.listeners {
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log.Printf("UPDATE_LISTENER %s: %p", node.Name(), listener)
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listener <- update
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}
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node.listeners_lock.Unlock()
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}
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// Basic implementation that sends the signal to the nodes channel
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func (node * BaseNode) Update(signal GraphSignal) error {
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log.Printf("UPDATE: BaseNode %s: %+v", node.Name(), signal)
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node.UpdateListeners(signal)
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return nil
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}
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