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/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala.sys.process
import scala.annotation.tailrec
/** A simple enough command line parser using shell quote conventions.
*/
private[scala] object Parser {
private final val DQ = '"'
private final val SQ = '\''
private final val EOF = -1
/** Split the line into tokens separated by whitespace or quotes.
*
* @return either an error message or reverse list of tokens
*/
def tokenize(line: String, errorFn: String => Unit): List[String] = {
import Character.isWhitespace
import java.lang.{StringBuilder => Builder}
import collection.mutable.ArrayBuffer
var accum: List[String] = Nil
var pos = 0
var start = 0
val qpos = new ArrayBuffer[Int](16) // positions of paired quotes
def cur: Int = if (done) EOF else line.charAt(pos)
def bump() = pos += 1
def done = pos >= line.length
// Skip to the next quote as given.
def skipToQuote(q: Int): Boolean = {
var escaped = false
def terminal: Boolean = cur match {
case _ if escaped => escaped = false ; false
case '\\' => escaped = true ; false
case `q` | EOF => true
case _ => false
}
while (!terminal) bump()
!done
}
// Skip to a word boundary, where words can be quoted and quotes can be escaped
def skipToDelim(): Boolean = {
var escaped = false
def quote() = { qpos += pos ; bump() }
@tailrec def advance(): Boolean = cur match {
case _ if escaped => escaped = false ; bump() ; advance()
case '\\' => escaped = true ; bump() ; advance()
case q @ (DQ | SQ) => { quote() ; skipToQuote(q) } && { quote() ; advance() }
case EOF => true
case c if isWhitespace(c) => true
case _ => bump(); advance()
}
advance()
}
def skipWhitespace() = while (isWhitespace(cur)) bump()
def copyText() = {
val buf = new Builder
var p = start
var i = 0
while (p < pos) {
if (i >= qpos.size) {
buf.append(line, p, pos)
p = pos
} else if (p == qpos(i)) {
buf.append(line, qpos(i)+1, qpos(i+1))
p = qpos(i+1)+1
i += 2
} else {
buf.append(line, p, qpos(i))
p = qpos(i)
}
}
buf.toString
}
def text() = {
val res =
if (qpos.isEmpty) line.substring(start, pos)
else if (qpos(0) == start && qpos(1) == pos) line.substring(start+1, pos-1)
else copyText()
qpos.clear()
res
}
def badquote() = errorFn(s"Unmatched quote [${qpos.last}](${line.charAt(qpos.last)})")
def badescape() = errorFn("trailing backslash")
@tailrec def loop(): List[String] = {
skipWhitespace()
start = pos
if (done) accum.reverse
else if (!skipToDelim()) { badquote(); Nil }
else if (pos > line.length) { badescape(); Nil }
else {
accum ::= text()
loop()
}
}
loop()
}
class ParseException(msg: String) extends RuntimeException(msg)
def tokenize(line: String): List[String] = tokenize(line, x => throw new ParseException(x))
}