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package dotty.tools.dotc.util
import scala.annotation.tailrec
import scala.collection.mutable
object DiffUtil {
private final val ANSI_DEFAULT = "\u001B[0m"
private final val ANSI_RED = "\u001B[31m"
private final val ANSI_GREEN = "\u001B[32m"
private final val DELETION_COLOR = ANSI_RED
private final val ADDITION_COLOR = ANSI_GREEN
@tailrec private def splitTokens(str: String, acc: List[String] = Nil): List[String] = {
if (str == "") {
acc.reverse
} else {
val head = str.charAt(0)
val (token, rest) = if (Character.isAlphabetic(head) || Character.isDigit(head)) {
str.span(c => Character.isAlphabetic(c) || Character.isDigit(c))
} else if (Character.isMirrored(head) || Character.isWhitespace(head)) {
str.splitAt(1)
} else {
str.span { c =>
!Character.isAlphabetic(c) && !Character.isDigit(c) &&
!Character.isMirrored(c) && !Character.isWhitespace(c)
}
}
splitTokens(rest, token :: acc)
}
}
/** @return a tuple of the (found, expected, changedPercentage) diffs as strings */
def mkColoredTypeDiff(found: String, expected: String): (String, String, Double) = {
var totalChange = 0
val foundTokens = splitTokens(found, Nil).toArray
val expectedTokens = splitTokens(expected, Nil).toArray
val diffExp = hirschberg(foundTokens, expectedTokens)
val diffAct = hirschberg(expectedTokens, foundTokens)
val exp = diffExp.collect {
case Unmodified(str) => str
case Inserted(str) =>
totalChange += str.length
ADDITION_COLOR + str + ANSI_DEFAULT
}.mkString
val fnd = diffAct.collect {
case Unmodified(str) => str
case Inserted(str) =>
totalChange += str.length
DELETION_COLOR + str + ANSI_DEFAULT
}.mkString
(fnd, exp, totalChange.toDouble / (expected.length + found.length))
}
def mkColoredLineDiff(expected: String, actual: String): String = {
val tokens = splitTokens(expected, Nil).toArray
val lastTokens = splitTokens(actual, Nil).toArray
val diff = hirschberg(lastTokens, tokens)
" |SOF\n" + diff.collect {
case Unmodified(str) =>
" |" + str
case Inserted(str) =>
ADDITION_COLOR + "e |" + str + ANSI_DEFAULT
case Modified(old, str) =>
DELETION_COLOR + "a |" + old + "\ne |" + ADDITION_COLOR + str + ANSI_DEFAULT
case Deleted(str) =>
DELETION_COLOR + "\na |" + str + ANSI_DEFAULT
}.mkString + "\n |EOF"
}
def mkColoredCodeDiff(code: String, lastCode: String, printDiffDel: Boolean): String = {
val tokens = splitTokens(code, Nil).toArray
val lastTokens = splitTokens(lastCode, Nil).toArray
val diff = hirschberg(lastTokens, tokens)
diff.collect {
case Unmodified(str) => str
case Inserted(str) => ADDITION_COLOR + str + ANSI_DEFAULT
case Modified(old, str) if printDiffDel => DELETION_COLOR + old + ADDITION_COLOR + str + ANSI_DEFAULT
case Modified(_, str) => ADDITION_COLOR + str + ANSI_DEFAULT
case Deleted(str) if printDiffDel => DELETION_COLOR + str + ANSI_DEFAULT
}.mkString
}
private sealed trait Patch
private final case class Unmodified(str: String) extends Patch
private final case class Modified(original: String, str: String) extends Patch
private final case class Deleted(str: String) extends Patch
private final case class Inserted(str: String) extends Patch
private def hirschberg(a: Array[String], b: Array[String]): Array[Patch] = {
def build(x: Array[String], y: Array[String], builder: mutable.ArrayBuilder[Patch]): Unit = {
if (x.isEmpty) {
builder += Inserted(y.mkString)
} else if (y.isEmpty) {
builder += Deleted(x.mkString)
} else if (x.length == 1 || y.length == 1) {
needlemanWunsch(x, y, builder)
} else {
val xlen = x.length
val xmid = xlen / 2
val ylen = y.length
val (x1, x2) = x.splitAt(xmid)
val leftScore = nwScore(x1, y)
val rightScore = nwScore(x2.reverse, y.reverse)
val scoreSum = (leftScore zip rightScore.reverse).map {
case (left, right) => left + right
}
val max = scoreSum.max
val ymid = scoreSum.indexOf(max)
val (y1, y2) = y.splitAt(ymid)
build(x1, y1, builder)
build(x2, y2, builder)
}
}
val builder = Array.newBuilder[Patch]
build(a, b, builder)
builder.result()
}
private def nwScore(x: Array[String], y: Array[String]): Array[Int] = {
def ins(s: String) = -2
def del(s: String) = -2
def sub(s1: String, s2: String) = if (s1 == s2) 2 else -1
val score = Array.fill(x.length + 1, y.length + 1)(0)
for (j <- 1 to y.length)
score(0)(j) = score(0)(j - 1) + ins(y(j - 1))
for (i <- 1 to x.length) {
score(i)(0) = score(i - 1)(0) + del(x(i - 1))
for (j <- 1 to y.length) {
val scoreSub = score(i - 1)(j - 1) + sub(x(i - 1), y(j - 1))
val scoreDel = score(i - 1)(j) + del(x(i - 1))
val scoreIns = score(i)(j - 1) + ins(y(j - 1))
score(i)(j) = scoreSub max scoreDel max scoreIns
}
}
Array.tabulate(y.length + 1)(j => score(x.length)(j))
}
private def needlemanWunsch(x: Array[String], y: Array[String], builder: mutable.ArrayBuilder[Patch]): Unit = {
def similarity(a: String, b: String) = if (a == b) 2 else -1
val d = 1
val score = Array.tabulate(x.length + 1, y.length + 1) { (i, j) =>
if (i == 0) d * j
else if (j == 0) d * i
else 0
}
for (i <- 1 to x.length) {
for (j <- 1 to y.length) {
val mtch = score(i - 1)(j - 1) + similarity(x(i - 1), y(j - 1))
val delete = score(i - 1)(j) + d
val insert = score(i)(j - 1) + d
score(i)(j) = mtch max insert max delete
}
}
var alignment = List.empty[Patch]
var i = x.length
var j = y.length
while (i > 0 || j > 0) {
if (i > 0 && j > 0 && score(i)(j) == score(i - 1)(j - 1) + similarity(x(i - 1), y(j - 1))) {
val newHead =
if (x(i - 1) == y(j - 1)) Unmodified(x(i - 1))
else Modified(x(i - 1), y(j - 1))
alignment = newHead :: alignment
i = i - 1
j = j - 1
} else if (i > 0 && score(i)(j) == score(i - 1)(j) + d) {
alignment = Deleted(x(i - 1)) :: alignment
i = i - 1
} else {
alignment = Inserted(y(j - 1)) :: alignment
j = j - 1
}
}
builder ++= alignment
}
}
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