scala.xml.MetaData.scala Maven / Gradle / Ivy
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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
package xml
import Utility.sbToString
import scala.annotation.tailrec
import scala.collection.AbstractIterable
import scala.collection.Seq
object MetaData {
/**
* appends all attributes from new_tail to attribs, without attempting to
* detect or remove duplicates. The method guarantees that all attributes
* from attribs come before the attributes in new_tail, but does not
* guarantee to preserve the relative order of attribs.
*
* Duplicates can be removed with `normalize`.
*/
@tailrec
def concatenate(attribs: MetaData, new_tail: MetaData): MetaData =
if (attribs.isNull) new_tail
else concatenate(attribs.next, attribs.copy(new_tail))
/**
* returns normalized MetaData, with all duplicates removed and namespace prefixes resolved to
* namespace URIs via the given scope.
*/
def normalize(attribs: MetaData, scope: NamespaceBinding): MetaData = {
def iterate(md: MetaData, normalized_attribs: MetaData, set: Set[String]): MetaData =
if (md.isNull) {
normalized_attribs
} else if (md.value == null)
iterate(md.next, normalized_attribs, set)
else {
val key: String = getUniversalKey(md, scope)
if (set(key))
iterate(md.next, normalized_attribs, set)
else
md.copy(iterate(md.next, normalized_attribs, set + key))
}
iterate(attribs, Null, Set())
}
/**
* returns key if md is unprefixed, pre+key is md is prefixed
*/
def getUniversalKey(attrib: MetaData, scope: NamespaceBinding): String = attrib match {
case prefixed: PrefixedAttribute => scope.getURI(prefixed.pre) + prefixed.key
case unprefixed: UnprefixedAttribute => unprefixed.key
}
/**
* returns MetaData with attributes updated from given MetaData
*/
def update(attribs: MetaData, scope: NamespaceBinding, updates: MetaData): MetaData =
normalize(concatenate(updates, attribs), scope)
}
/**
* This class represents an attribute and at the same time a linked list of
* attributes. Every instance of this class is either
* - an instance of `UnprefixedAttribute key,value` or
* - an instance of `PrefixedAttribute namespace_prefix,key,value` or
* - `Null`, the empty attribute list.
*
* Namespace URIs are obtained by using the namespace scope of the element
* owning this attribute (see `getNamespace`).
*/
// Note: used by the Scala compiler.
abstract class MetaData
extends AbstractIterable[MetaData]
with Iterable[MetaData]
with Equality
with Serializable
{
private[xml] def isNull: Boolean = this.eq(Null)
/**
* Updates this MetaData with the MetaData given as argument. All attributes that occur in updates
* are part of the resulting MetaData. If an attribute occurs in both this instance and
* updates, only the one in updates is part of the result (avoiding duplicates). For prefixed
* attributes, namespaces are resolved using the given scope, which defaults to TopScope.
*
* @param updates MetaData with new and updated attributes
* @return a new MetaData instance that contains old, new and updated attributes
*/
def append(updates: MetaData, scope: NamespaceBinding = TopScope): MetaData =
MetaData.update(this, scope, updates)
/**
* Gets value of unqualified (unprefixed) attribute with given key, null if not found
*
* @param key
* @return value as Seq[Node] if key is found, null otherwise
*/
def apply(key: String): Seq[Node]
/**
* convenience method, same as `apply(namespace, owner.scope, key)`.
*
* @param namespace_uri namespace uri of key
* @param owner the element owning this attribute list
* @param key the attribute key
*/
final def apply(namespace_uri: String, owner: Node, key: String): Seq[Node] =
apply(namespace_uri, owner.scope, key)
/**
* Gets value of prefixed attribute with given key and namespace, null if not found
*
* @param namespace_uri namespace uri of key
* @param scp a namespace scp (usually of the element owning this attribute list)
* @param k to be looked for
* @return value as Seq[Node] if key is found, null otherwise
*/
def apply(namespace_uri: String, scp: NamespaceBinding, k: String): Seq[Node]
/**
* returns a copy of this MetaData item with next field set to argument.
*/
def copy(next: MetaData): MetaData
/** if owner is the element of this metadata item, returns namespace */
def getNamespace(owner: Node): String
def hasNext: Boolean = Null != next
def length: Int = length(0)
def length(i: Int): Int = next.length(i + 1)
def isPrefixed: Boolean
override def canEqual(other: Any): Boolean = other match {
case _: MetaData => true
case _ => false
}
override def strict_==(other: Equality): Boolean = other match {
case m: MetaData => this.asAttrMap == m.asAttrMap
case _ => false
}
override protected def basisForHashCode: Seq[Any] = List(this.asAttrMap)
/** filters this sequence of meta data */
override def filter(f: MetaData => Boolean): MetaData =
if (f(this)) copy(next.filter(f))
else next.filter(f)
def reverse: MetaData =
foldLeft(Null: MetaData) { (x, xs) =>
xs.copy(x)
}
/** returns key of this MetaData item */
def key: String
/** returns value of this MetaData item */
def value: Seq[Node]
/**
* Returns a String containing "prefix:key" if the first key is
* prefixed, and "key" otherwise.
*/
def prefixedKey: String = this match {
case x: Attribute if x.isPrefixed => s"${x.pre}:$key"
case _ => key
}
/**
* Returns a Map containing the attributes stored as key/value pairs.
*/
def asAttrMap: Map[String, String] =
iterator.map(x => (x.prefixedKey, x.value.text)).toMap
/** returns Null or the next MetaData item */
def next: MetaData
/**
* Gets value of unqualified (unprefixed) attribute with given key, None if not found
*
* @param key
* @return value in Some(Seq[Node]) if key is found, None otherwise
*/
final def get(key: String): Option[Seq[Node]] = Option(apply(key))
/** same as get(uri, owner.scope, key) */
final def get(uri: String, owner: Node, key: String): Option[Seq[Node]] =
get(uri, owner.scope, key)
/**
* gets value of qualified (prefixed) attribute with given key.
*
* @param uri namespace of key
* @param scope a namespace scp (usually of the element owning this attribute list)
* @param key to be looked fore
* @return value as `Some[Seq[Node]]` if key is found, None otherwise
*/
final def get(uri: String, scope: NamespaceBinding, key: String): Option[Seq[Node]] =
Option(apply(uri, scope, key))
protected def toString1: String = sbToString(toString1)
// appends string representations of single attribute to StringBuilder
protected def toString1(sb: StringBuilder): Unit
override def toString: String = sbToString(buildString)
def buildString(sb: StringBuilder): StringBuilder = {
sb.append(' ')
toString1(sb)
next.buildString(sb)
}
/**
*/
def wellformed(scope: NamespaceBinding): Boolean
def remove(key: String): MetaData
def remove(namespace: String, scope: NamespaceBinding, key: String): MetaData
final def remove(namespace: String, owner: Node, key: String): MetaData =
remove(namespace, owner.scope, key)
}