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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
/// Returns the bottommost node whose subtree contains both `lhs` and `rhs`.
public func findCommonAncestorOrSelf(_ lhs: Syntax, _ rhs: Syntax) -> Syntax? {
var lhs: Syntax? = lhs
var rhs: Syntax? = rhs
while lhs != nil && rhs != nil {
if lhs == rhs {
return lhs
}
if let lhsUnwrapped = lhs, let rhsUnwrapped = rhs {
if lhsUnwrapped.id < rhsUnwrapped.id {
rhs = rhsUnwrapped.parent
} else {
lhs = lhsUnwrapped.parent
}
}
}
return nil
}
/// Returns the bottommost node whose subtree contains all nodes in `nodes`.
public func findCommonAncestorOrSelf(_ nodes: [Syntax]) -> Syntax? {
var commonParent = nodes.first
for node in nodes.dropFirst() {
if let commonParentUnwrapped = commonParent {
commonParent = findCommonAncestorOrSelf(commonParentUnwrapped, node)
} else {
return nil
}
}
return commonParent
}
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