/
compiletime.scala
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/
compiletime.scala
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/*
* Copyright (c) 2016 Frank S. Thomas
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package shapeless.test
import scala.language.experimental.macros
import scala.concurrent.duration.FiniteDuration
import scala.reflect.macros.blackbox
/**
* Utility that measures the compilation time of a code fragment.
*
* `compileTime` takes a code fragment as `String`, measures the time
* it takes to parse and typecheck it and returns that time as a
* `FiniteDuration`.
*
* Example: {{{
* scala> compileTime(""" Generic[(Int, Option[String])] """)
* res0: FiniteDuration = 43153718 nanoseconds
* }}}
*/
object compileTime {
def apply(code: String): FiniteDuration = macro CompileTimeMacros.applyImpl
}
@macrocompat.bundle
class CompileTimeMacros(val c: blackbox.Context) {
import c.universe._
def applyImpl(code: Tree): Tree = {
def wallClock(codeStr: String): Long = {
try {
val t1 = System.nanoTime()
c.typecheck(c.parse(codeStr))
val t2 = System.nanoTime()
t2 - t1
} catch {
case ex: Exception => c.abort(c.enclosingPosition, ex.getMessage)
}
}
val Literal(Constant(codeStr: String)) = code
val elapsedTime = wallClock(codeStr)
q"_root_.scala.concurrent.duration.Duration.fromNanos($elapsedTime)"
}
}