Index backend commands for path lookup

internal/cobra/parse.go

@@ -71,8 +71,9 @@ func RenderHelp(root *Command, path []string) (string, *Failure) {
 	if err != nil {
 		return "", &Failure{Message: err.Error()}
 	}
-	declaration := declarationFor(nodes, selected)
-	if declaration == nil || len(remaining) != 0 || !equalPath(path, pathFor(root, declaration)) {
+	declaration := nodes[selected]
+	selectedPath, pathOK := pathFor(selected, nodes)
+	if declaration == nil || !pathOK || len(remaining) != 0 || !equalPath(path, selectedPath) {
 		return "", &Failure{Message: "help path is not registered"}
 	}
 	selected.SetOut(buffer)
@@ -91,8 +92,9 @@ func UsageLine(root *Command, path []string) (string, *Failure) {
 	options := normalizeOptions(ParseOptions{Context: context.Background(), In: strings.NewReader(""), Out: io.Discard, Err: io.Discard})
 	backendRoot, nodes := buildTree(root, options)
 	selected, remaining, err := backendRoot.Find(path)
-	declaration := declarationFor(nodes, selected)
-	if err != nil || declaration == nil || len(remaining) != 0 || !equalPath(path, pathFor(root, declaration)) {
+	declaration := nodes[selected]
+	selectedPath, pathOK := pathFor(selected, nodes)
+	if err != nil || declaration == nil || !pathOK || len(remaining) != 0 || !equalPath(path, selectedPath) {
 		return "", &Failure{Message: "usage path is not registered"}
 	}
 	line := selected.UseLine()
@@ -128,11 +130,15 @@ func Parse(root *Command, argv []string, options ParseOptions) Result {
 	if selected == nil {
 		return failure(result, "no command was selected")
 	}
-	selectedNode := declarationFor(nodes, selected)
+	selectedNode := nodes[selected]
 	if selectedNode == nil {
 		return failure(result, "selected command is not part of the declared tree")
 	}
-	result.Path = pathFor(root, selectedNode)
+	var pathOK bool
+	result.Path, pathOK = pathFor(selected, nodes)
+	if !pathOK {
+		return failure(result, "selected command is not part of the declared tree")
+	}
 	consumed := len(leading) - len(unconsumed)
 	if consumed != len(result.Path) || !equalPath(leading[:consumed], result.Path) {
 		return failure(result, "command path must match a registered command exactly")
@@ -180,8 +186,8 @@ func normalizeOptions(options ParseOptions) ParseOptions {
 	return options
 }
 
-func buildTree(root *Command, options ParseOptions) (*spfcobra.Command, map[*Command]*spfcobra.Command) {
-	nodes := make(map[*Command]*spfcobra.Command)
+func buildTree(root *Command, options ParseOptions) (*spfcobra.Command, map[*spfcobra.Command]*Command) {
+	nodes := make(map[*spfcobra.Command]*Command)
 	var build func(*Command) *spfcobra.Command
 	build = func(declaration *Command) *spfcobra.Command {
 		backend := &spfcobra.Command{
@@ -223,7 +229,7 @@ func buildTree(root *Command, options ParseOptions) (*spfcobra.Command, map[*Com
 		// Cobra's automatic help flag is suppressed because CommandKit declares
 		// and interprets the local help flag itself.
 		backend.SetHelpCommand(nil)
-		nodes[declaration] = backend
+		nodes[backend] = declaration
 		for _, child := range declaration.Children {
 			backend.AddCommand(build(child))
 		}
@@ -320,15 +326,6 @@ func equalPath(left, right []string) bool {
 	return true
 }
 
-func declarationFor(nodes map[*Command]*spfcobra.Command, selected *spfcobra.Command) *Command {
-	for declaration, backend := range nodes {
-		if backend == selected {
-			return declaration
-		}
-	}
-	return nil
-}
-
 func splitRoutingPrefix(argv []string) ([]string, []string) {
 	for index, argument := range argv {
 		if argument == "--" || (strings.HasPrefix(argument, "-") && argument != "-") {
@@ -338,29 +335,21 @@ func splitRoutingPrefix(argv []string) ([]string, []string) {
 	return append([]string(nil), argv...), nil
 }
 
-func pathFor(root, selected *Command) []string {
+func pathFor(selected *spfcobra.Command, declarations map[*spfcobra.Command]*Command) ([]string, bool) {
 	var reverse []string
-	for current := selected; current != nil && current != root; {
-		reverse = append(reverse, current.Name)
-		current = parentOf(root, current)
-	}
-	path := make([]string, len(reverse))
-	for index := range reverse {
-		path[len(reverse)-index-1] = reverse[index]
-	}
-	return path
-}
-
-func parentOf(root, target *Command) *Command {
-	for _, child := range root.Children {
-		if child == target {
-			return root
+	for current := selected; current != nil; current = current.Parent() {
+		declaration := declarations[current]
+		if declaration == nil {
+			return nil, false
 		}
-		if parent := parentOf(child, target); parent != nil {
-			return parent
+		if current.Parent() != nil {
+			reverse = append(reverse, declaration.Name)
 		}
 	}
-	return nil
+	for left, right := 0, len(reverse)-1; left < right; left, right = left+1, right-1 {
+		reverse[left], reverse[right] = reverse[right], reverse[left]
+	}
+	return reverse, true
 }
 
 func failure(result Result, message string) Result {