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import llbuild
typealias Compute = ([Int]) -> Int
class SimpleTask: Task {
let inputs: [Key]
var values: [Int]
let compute: Compute
init(_ inputs: [Key], compute: @escaping Compute) {
self.inputs = inputs
values = [Int](repeating: 0, count: inputs.count)
self.compute = compute
}
func start(_ engine: TaskBuildEngine) {
for (idx, input) in inputs.enumerated() {
engine.taskNeedsInput(input, inputID: idx)
}
}
func provideValue(_ engine: TaskBuildEngine, inputID: Int, value: Value) {
values[inputID] = Int(value.toString())!
}
func inputsAvailable(_ engine: TaskBuildEngine) {
let result = compute(values)
engine.taskIsComplete(Value("\(result)"), forceChange: false)
}
}
class SimpleBuildEngineDelegate: BuildEngineDelegate {
var builtKeys = [Key]()
func lookupRule(_ key: Key) -> Rule {
switch key.toString() {
case "A":
return SimpleRule([]) { arr in
precondition(self.builtKeys.isEmpty)
self.builtKeys.append(key)
return 2
}
case "B":
return SimpleRule([]) { arr in
precondition(self.builtKeys.count == 1)
self.builtKeys.append(key)
return 3
}
case "C":
return SimpleRule([Key("A"), Key("B")]) { arr in
precondition(self.builtKeys.count == 2)
precondition(self.builtKeys[0].toString() == "A")
precondition(self.builtKeys[1].toString() == "B")
self.builtKeys.append(key)
return arr[0] * arr[1]
}
default: fatalError("Unexpected key \(key) lookup")
}
}
}
class SimpleRule: Rule {
let inputs: [Key]
let compute: Compute
init(_ inputs: [Key], compute: @escaping Compute) {
self.inputs = inputs
self.compute = compute
}
func createTask() -> Task {
return SimpleTask(inputs, compute: compute)
}
}
let delegate = SimpleBuildEngineDelegate()
var engine = BuildEngine(delegate: delegate)
// C depends on A and B
var result = engine.build(key: Key("C"))
print("\(result.toString())")
precondition(result.toString() == "6")
// Make sure building already built keys do not re-compute.
delegate.builtKeys.removeAll()
precondition(delegate.builtKeys.isEmpty)
result = engine.build(key: Key("A"))
precondition(result.toString() == "2")
precondition(delegate.builtKeys.isEmpty)
result = engine.build(key: Key("B"))
precondition(result.toString() == "3")
precondition(delegate.builtKeys.isEmpty)
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