112 lines
2.1 KiB
Go
112 lines
2.1 KiB
Go
package crush
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// Select choose nodes
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func Select(parent Node, input uint32, count uint32, nodeType uint16, c Comparitor) []Node {
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var results []Node
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//if len(parent.Children) < count {
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// panic("Asked for more node than are available")
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//}
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var rPrime uint32
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for r := uint32(1); r <= count; r++ {
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var failure = uint32(0)
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var loopbacks = 0
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var escape = false
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var retryOrigin bool
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var out Node
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for {
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retryOrigin = false
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var in = parent
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var skip = make(map[Node]bool)
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var retryNode bool
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for {
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retryNode = false
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rPrime = uint32(r + failure)
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out = in.Select(input, rPrime)
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if out.GetType() != nodeType {
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in = out
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retryNode = true
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} else {
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if contains(results, out) {
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if !nodesAvailable(in, results, skip) {
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if loopbacks == 150 {
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escape = true
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break
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}
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loopbacks++
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retryOrigin = true
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} else {
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retryNode = true
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}
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failure++
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} else if c != nil && !c(out) {
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skip[out] = true
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if !nodesAvailable(in, results, skip) {
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if loopbacks == 150 {
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escape = true
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break
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}
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loopbacks++
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retryOrigin = true
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} else {
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retryNode = true
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}
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failure++
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} else if isDefunct(out) {
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failure++
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if loopbacks == 150 {
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escape = true
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break
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}
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loopbacks++
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retryOrigin = true
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} else {
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break
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}
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}
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if !retryNode {
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break
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}
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}
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if !retryOrigin {
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break
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}
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}
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if escape {
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continue
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}
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results = append(results, out)
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}
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return results
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}
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func nodesAvailable(parent Node, selected []Node, rejected map[Node]bool) bool {
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var children = parent.GetChildren()
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for _, child := range children {
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if !isDefunct(child) {
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if ok := contains(selected, child); !ok {
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if _, ok := rejected[child]; !ok {
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return true
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}
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}
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}
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}
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return false
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}
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func contains(s []Node, n Node) bool {
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for _, a := range s {
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if a == n {
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return true
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}
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}
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return false
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}
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func isDefunct(n Node) bool {
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if n.IsLeaf() && n.IsFailed() {
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return true
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}
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return false
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}
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