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Standard library for the Scala Programming Language
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.xml
import scala.collection.mutable
import parsing.XhtmlEntities
import scala.language.implicitConversions
/**
* The `Utility` object provides utility functions for processing instances
* of bound and not bound XML classes, as well as escaping text nodes.
*
* @author Burak Emir
*/
object Utility extends AnyRef with parsing.TokenTests {
final val SU = '\u001A'
// [Martin] This looks dubious. We don't convert StringBuilders to
// Strings anywhere else, why do it here?
implicit def implicitSbToString(sb: StringBuilder) = sb.toString()
// helper for the extremely oft-repeated sequence of creating a
// StringBuilder, passing it around, and then grabbing its String.
private [xml] def sbToString(f: (StringBuilder) => Unit): String = {
val sb = new StringBuilder
f(sb)
sb.toString
}
private[xml] def isAtomAndNotText(x: Node) = x.isAtom && !x.isInstanceOf[Text]
/** Trims an element - call this method, when you know that it is an
* element (and not a text node) so you know that it will not be trimmed
* away. With this assumption, the function can return a `Node`, rather
* than a `Seq[Node]`. If you don't know, call `trimProper` and account
* for the fact that you may get back an empty sequence of nodes.
*
* Precondition: node is not a text node (it might be trimmed)
*/
def trim(x: Node): Node = x match {
case Elem(pre, lab, md, scp, child@_*) =>
Elem(pre, lab, md, scp, (child flatMap trimProper):_*)
}
/** trim a child of an element. `Attribute` values and `Atom` nodes that
* are not `Text` nodes are unaffected.
*/
def trimProper(x:Node): Seq[Node] = x match {
case Elem(pre,lab,md,scp,child@_*) =>
Elem(pre,lab,md,scp, (child flatMap trimProper):_*)
case Text(s) =>
new TextBuffer().append(s).toText
case _ =>
x
}
/** returns a sorted attribute list */
def sort(md: MetaData): MetaData = if((md eq Null) || (md.next eq Null)) md else {
val key = md.key
val smaller = sort(md.filter { m => m.key < key })
val greater = sort(md.filter { m => m.key > key })
smaller.foldRight (md copy greater) ((x, xs) => x copy xs)
}
/** Return the node with its attribute list sorted alphabetically
* (prefixes are ignored) */
def sort(n:Node): Node = n match {
case Elem(pre,lab,md,scp,child@_*) =>
Elem(pre,lab,sort(md),scp, (child map sort):_*)
case _ => n
}
/**
* Escapes the characters < > & and " from string.
*/
final def escape(text: String): String = sbToString(escape(text, _))
object Escapes {
/** For reasons unclear escape and unescape are a long ways from
* being logical inverses. */
val pairs = Map(
"lt" -> '<',
"gt" -> '>',
"amp" -> '&',
"quot" -> '"'
// enigmatic comment explaining why this isn't escaped --
// is valid xhtml but not html, and IE doesn't know it, says jweb
// "apos" -> '\''
)
val escMap = pairs map { case (s, c) => c-> ("&%s;" format s) }
val unescMap = pairs ++ Map("apos" -> '\'')
}
import Escapes.{ escMap, unescMap }
/**
* Appends escaped string to `s`.
*/
final def escape(text: String, s: StringBuilder): StringBuilder = {
// Implemented per XML spec:
// http://www.w3.org/International/questions/qa-controls
// imperative code 3x-4x faster than current implementation
// dpp (David Pollak) 2010/02/03
val len = text.length
var pos = 0
while (pos < len) {
text.charAt(pos) match {
case '<' => s.append("<")
case '>' => s.append(">")
case '&' => s.append("&")
case '"' => s.append(""")
case '\n' => s.append('\n')
case '\r' => s.append('\r')
case '\t' => s.append('\t')
case c => if (c >= ' ') s.append(c)
}
pos += 1
}
s
}
/**
* Appends unescaped string to `s`, `amp` becomes `&`,
* `lt` becomes `<` etc..
*
* @return `'''null'''` if `ref` was not a predefined entity.
*/
final def unescape(ref: String, s: StringBuilder): StringBuilder =
((unescMap get ref) map (s append _)).orNull
/**
* Returns a set of all namespaces used in a sequence of nodes
* and all their descendants, including the empty namespaces.
*/
def collectNamespaces(nodes: Seq[Node]): mutable.Set[String] =
nodes.foldLeft(new mutable.HashSet[String]) { (set, x) => collectNamespaces(x, set) ; set }
/**
* Adds all namespaces in node to set.
*/
def collectNamespaces(n: Node, set: mutable.Set[String]) {
if (n.doCollectNamespaces) {
set += n.namespace
for (a <- n.attributes) a match {
case _:PrefixedAttribute =>
set += a.getNamespace(n)
case _ =>
}
for (i <- n.child)
collectNamespaces(i, set)
}
}
// def toXML(
// x: Node,
// pscope: NamespaceBinding = TopScope,
// sb: StringBuilder = new StringBuilder,
// stripComments: Boolean = false,
// decodeEntities: Boolean = true,
// preserveWhitespace: Boolean = false,
// minimizeTags: Boolean = false): String =
// {
// toXMLsb(x, pscope, sb, stripComments, decodeEntities, preserveWhitespace, minimizeTags)
// sb.toString()
// }
/**
* Serialize the provided Node to the provided StringBuilder.
*
* Note that calling this source-compatible method will result in the same old, arguably almost universally unwanted,
* behaviour.
*/
@deprecated("Please use `serialize` instead and specify a `minimizeTags` parameter", "2.10.0")
def toXML(
x: Node,
pscope: NamespaceBinding = TopScope,
sb: StringBuilder = new StringBuilder,
stripComments: Boolean = false,
decodeEntities: Boolean = true,
preserveWhitespace: Boolean = false,
minimizeTags: Boolean = false): StringBuilder =
{
serialize(x, pscope, sb, stripComments, decodeEntities, preserveWhitespace, if (minimizeTags) MinimizeMode.Always else MinimizeMode.Never)
}
/**
* Serialize an XML Node to a StringBuilder.
*
* This is essentially a minor rework of `toXML` that can't have the same name due to an unfortunate
* combination of named/default arguments and overloading.
*
* @todo use a Writer instead
*/
def serialize(
x: Node,
pscope: NamespaceBinding = TopScope,
sb: StringBuilder = new StringBuilder,
stripComments: Boolean = false,
decodeEntities: Boolean = true,
preserveWhitespace: Boolean = false,
minimizeTags: MinimizeMode.Value = MinimizeMode.Default): StringBuilder =
{
x match {
case c: Comment if !stripComments => c buildString sb
case s: SpecialNode => s buildString sb
case g: Group => for (c <- g.nodes) serialize(c, g.scope, sb, minimizeTags = minimizeTags) ; sb
case el: Elem =>
// print tag with namespace declarations
sb.append('<')
el.nameToString(sb)
if (el.attributes ne null) el.attributes.buildString(sb)
el.scope.buildString(sb, pscope)
if (el.child.isEmpty &&
(minimizeTags == MinimizeMode.Always ||
(minimizeTags == MinimizeMode.Default && el.minimizeEmpty)))
{
// no children, so use short form: ...
sb.append('>')
sequenceToXML(el.child, el.scope, sb, stripComments)
sb.append("')
}
case _ => throw new IllegalArgumentException("Don't know how to serialize a " + x.getClass.getName)
}
}
def sequenceToXML(
children: Seq[Node],
pscope: NamespaceBinding = TopScope,
sb: StringBuilder = new StringBuilder,
stripComments: Boolean = false,
decodeEntities: Boolean = true,
preserveWhitespace: Boolean = false,
minimizeTags: MinimizeMode.Value = MinimizeMode.Default): Unit =
{
if (children.isEmpty) return
else if (children forall isAtomAndNotText) { // add space
val it = children.iterator
val f = it.next
serialize(f, pscope, sb, stripComments, decodeEntities, preserveWhitespace, minimizeTags)
while (it.hasNext) {
val x = it.next
sb.append(' ')
serialize(x, pscope, sb, stripComments, decodeEntities, preserveWhitespace, minimizeTags)
}
}
else children foreach { serialize(_, pscope, sb, stripComments, decodeEntities, preserveWhitespace, minimizeTags) }
}
/**
* Returns prefix of qualified name if any.
*/
final def prefix(name: String): Option[String] = (name indexOf ':') match {
case -1 => None
case i => Some(name.substring(0, i))
}
/**
* Returns a hashcode for the given constituents of a node
*/
def hashCode(pre: String, label: String, attribHashCode: Int, scpeHash: Int, children: Seq[Node]) =
scala.util.hashing.MurmurHash3.orderedHash(label +: attribHashCode +: scpeHash +: children, pre.##)
def appendQuoted(s: String): String = sbToString(appendQuoted(s, _))
/**
* Appends "s" if string `s` does not contain ",
* 's' otherwise.
*/
def appendQuoted(s: String, sb: StringBuilder) = {
val ch = if (s contains '"') '\'' else '"'
sb.append(ch).append(s).append(ch)
}
/**
* Appends "s" and escapes and " i s with \"
*/
def appendEscapedQuoted(s: String, sb: StringBuilder): StringBuilder = {
sb.append('"')
for (c <- s) c match {
case '"' => sb.append('\\'); sb.append('"')
case _ => sb.append(c)
}
sb.append('"')
}
def getName(s: String, index: Int): String = {
if (index >= s.length) null
else {
val xs = s drop index
if (xs.nonEmpty && isNameStart(xs.head)) xs takeWhile isNameChar
else ""
}
}
/**
* Returns `'''null'''` if the value is a correct attribute value,
* error message if it isn't.
*/
def checkAttributeValue(value: String): String = {
var i = 0
while (i < value.length) {
value.charAt(i) match {
case '<' =>
return "< not allowed in attribute value";
case '&' =>
val n = getName(value, i+1)
if (n eq null)
return "malformed entity reference in attribute value ["+value+"]";
i = i + n.length + 1
if (i >= value.length || value.charAt(i) != ';')
return "malformed entity reference in attribute value ["+value+"]";
case _ =>
}
i = i + 1
}
null
}
def parseAttributeValue(value: String): Seq[Node] = {
val sb = new StringBuilder
var rfb: StringBuilder = null
val nb = new NodeBuffer()
val it = value.iterator
while (it.hasNext) {
var c = it.next
// entity! flush buffer into text node
if (c == '&') {
c = it.next
if (c == '#') {
c = it.next
val theChar = parseCharRef ({ ()=> c },{ () => c = it.next },{s => throw new RuntimeException(s)}, {s => throw new RuntimeException(s)})
sb.append(theChar)
}
else {
if (rfb eq null) rfb = new StringBuilder()
rfb append c
c = it.next
while (c != ';') {
rfb.append(c)
c = it.next
}
val ref = rfb.toString()
rfb.clear()
unescape(ref,sb) match {
case null =>
if (sb.length > 0) { // flush buffer
nb += Text(sb.toString())
sb.clear()
}
nb += EntityRef(ref) // add entityref
case _ =>
}
}
}
else sb append c
}
if (sb.length > 0) { // flush buffer
val x = Text(sb.toString())
if (nb.length == 0)
return x
else
nb += x
}
nb
}
/**
* {{{
* CharRef ::= "&#" '0'..'9' {'0'..'9'} ";"
* | "&#x" '0'..'9'|'A'..'F'|'a'..'f' { hexdigit } ";"
* }}}
* See [66]
*/
def parseCharRef(ch: () => Char, nextch: () => Unit, reportSyntaxError: String => Unit, reportTruncatedError: String => Unit): String = {
val hex = (ch() == 'x') && { nextch(); true }
val base = if (hex) 16 else 10
var i = 0
while (ch() != ';') {
ch() match {
case '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' =>
i = i * base + ch().asDigit
case 'a' | 'b' | 'c' | 'd' | 'e' | 'f'
| 'A' | 'B' | 'C' | 'D' | 'E' | 'F' =>
if (! hex)
reportSyntaxError("hex char not allowed in decimal char ref\n" +
"Did you mean to write &#x ?")
else
i = i * base + ch().asDigit
case SU =>
reportTruncatedError("")
case _ =>
reportSyntaxError("character '" + ch() + "' not allowed in char ref\n")
}
nextch()
}
new String(Array(i), 0, 1)
}
}