forked from extern/smegmesh
85 lines
2.2 KiB
Go
85 lines
2.2 KiB
Go
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package conn
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import (
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"errors"
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"slices"
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"github.com/tim-beatham/wgmesh/pkg/lib"
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)
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// ConnectionWindow maintains a sliding window of connections between users
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type ConnectionWindow interface {
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// GetWindow is a list of connections to choose from
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GetWindow() []string
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// SlideConnection removes a node from the window and adds a random node
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// not already in the window. connList represents the list of possible
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// connections to choose from
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SlideConnection(connList []string) error
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// PushConneciton is used when connection list less than window size.
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PutConnection(conn []string) error
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// IsFull returns true if the window is full. In which case we must slide the window
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IsFull() bool
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}
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type ConnectionWindowImpl struct {
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window []string
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windowSize int
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}
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// GetWindow gets the current list of active connections in
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// the window
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func (c *ConnectionWindowImpl) GetWindow() []string {
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return c.window
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}
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// SlideConnection slides the connection window by one shuffling items
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// in the windows
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func (c *ConnectionWindowImpl) SlideConnection(connList []string) error {
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// If the number of peer connections is less than the length of the window
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// then exit early. Can't slide the window it should contain all nodes!
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if len(c.window) < c.windowSize {
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return nil
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}
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filter := func(node string) bool {
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return !slices.Contains(c.window, node)
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}
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pool := lib.Filter(connList, filter)
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newNode := lib.RandomSubsetOfLength(pool, 1)
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if len(newNode) == 0 {
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return errors.New("could not slide window")
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}
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for i := len(c.window) - 1; i >= 1; i-- {
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c.window[i] = c.window[i-1]
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}
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c.window[0] = newNode[0]
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return nil
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}
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// PutConnection put random connections in the connection
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func (c *ConnectionWindowImpl) PutConnection(connList []string) error {
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if len(c.window) >= c.windowSize {
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return errors.New("cannot place connection. Window full need to slide")
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}
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c.window = lib.RandomSubsetOfLength(connList, c.windowSize)
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return nil
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}
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func (c *ConnectionWindowImpl) IsFull() bool {
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return len(c.window) >= c.windowSize
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}
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func NewConnectionWindow(windowLength int) ConnectionWindow {
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window := &ConnectionWindowImpl{
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window: make([]string, 0),
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windowSize: windowLength,
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}
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return window
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}
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