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// Copyright 2018 UANGEL
//
// 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 com.thing2x.smqd
import com.thing2x.smqd.FilterPathPrefix.FilterPathPrefix
import com.typesafe.scalalogging.Logger
import scala.annotation.tailrec
import scala.collection.concurrent.TrieMap
import scala.collection.immutable.HashMap
import scala.collection.mutable
// 2018. 5. 31. - Created by Kwon, Yeong Eon
/**
*
*/
sealed abstract class TName(val name: String) extends Serializable {
def isLocalPrefix: Boolean = name == "$local"
def isQueuePrefix: Boolean = name == "$queue"
def isSharePrefix: Boolean = name == "$share"
override def hashCode: Int = name.hashCode
override def equals(obj: scala.Any): Boolean = {
if (!obj.isInstanceOf[TName]){
false
}
else{
val other = obj.asInstanceOf[TName]
this.name == other.name
}
}
}
class TNameToken(name: String) extends TName(name)
class TNameInvalid(name: String, val reason: String) extends TName(name)
class TNameEmpty extends TName("")
abstract class TNameWildcard(name: String) extends TName(name)
object TNameMultiWildcard extends TNameWildcard("#")
object TNameSingleWildcard extends TNameWildcard("+")
object TName {
def apply(name: String, isLast: Boolean = false): TName = {
name match {
// [MQTT-4.7.1-2] The multi-level wildcard character MUST be specified either on its own or following a topic
// level seperator. In either case it MUST be the last character specified in the Topic Filter
case "#" if isLast => TNameMultiWildcard
case "+" => TNameSingleWildcard
case "" => new TNameEmpty()
case _ if name.contains('#') => new TNameInvalid(name, "name contains invalid character(#)")
case _ if name.contains("+") => new TNameInvalid(name, "name contains invalid character(+)")
case _ if name.contains("/") => new TNameInvalid(name, "name contains invalid character(/)")
case _ => new TNameToken(name)
}
}
def parse(path: String): Seq[TName] = {
def _parse(path: String): Seq[TName] = {
var offset = 0
val lastIndex = math.max(path.length - 1, 0)
path.zipWithIndex.flatMap{ case (ch, idx) =>
if (ch == '/') {
val from = offset
offset = idx + 1
if (idx == lastIndex) {
Seq(TName(path.substring(from, idx)), TName(""))
}
else {
Some(TName(path.substring(from, idx)))
}
}
else {
if (idx == lastIndex) {
Some(TName(path.substring(offset), isLast = true))
}
else {
None
}
}
}
}
if (path == "")
Seq(new TNameToken(""))
else if (path.head == '/')
if (path.length == 1)
Seq(TName(""), TName(""))
else
TName("") +: _parse(path.drop(1))
else
_parse(path)
}
}
trait TPath extends Ordered[TPath]{
def tokens: Seq[TName]
override val toString: String = {
tokens.map(_.name).mkString("/")
}
override def hashCode(): Int = {
toString.hashCode
}
override def equals(obj: scala.Any): Boolean = {
if (!obj.isInstanceOf[TPath]){
false
}
else{
val other = obj.asInstanceOf[TPath]
if (tokens.size != other.tokens.size) {
false
}
else {
!tokens.zip(other.tokens).exists(t => t._1 != t._2)
}
}
}
override def compare(that: TPath): Int = {
this.toString.compare(that.toString)
}
}
object TopicPath {
def apply(path: String): TopicPath = TPath.parseForTopic(path).get
def parse(path: String): Option[TopicPath] = TPath.parseForTopic(path)
}
case class TopicPath(tokens: Seq[TName]) extends TPath
object FilterPathPrefix extends Enumeration {
type FilterPathPrefix = Value
val NoPrefix: FilterPathPrefix = Value("none")
val Local: FilterPathPrefix = Value("local")
val Queue: FilterPathPrefix = Value("queue")
val Share: FilterPathPrefix = Value("share")
}
import FilterPathPrefix._
object FilterPath {
def apply(path: String): FilterPath = TPath.parseForFilter(path).get
def parse(path: String): Option[FilterPath] = TPath.parseForFilter(path)
}
case class FilterPath(tokens: Seq[TName], prefix: FilterPathPrefix = NoPrefix, group: Option[String] = None) extends TPath {
val isLocal: Boolean = prefix == Local
val isShared: Boolean = prefix == Queue || prefix == Share
def matchFor(path: TopicPath): Boolean = {
var p = path.tokens
tokens.foreach {
case t: TNameToken =>
if (t.name != p.head.name) return false
p = p.tail
case TNameMultiWildcard =>
if (p.nonEmpty) return true
case TNameSingleWildcard =>
if (p.isEmpty) return false
p = p.tail
case _ =>
return false
}
p.isEmpty
}
override val toString: String = {
val prefixStr = prefix match {
case Local => "$local/"
case Queue => "$queue/"
case Share => "$share/" + group.get + "/"
case NoPrefix => ""
}
tokens.map(_.name).mkString(prefixStr, "/", "")
}
def debug: String = {
val prefixStr = prefix match {
case Local => "[$local]"
case Queue => "[$queue]"
case Share => "[$share (" + group.get + ")]"
case NoPrefix => "-"
}
tokens.map(_.name).mkString(prefixStr, ", ", "")
}
def toByteArray: Array[Byte] = {
this.toString.getBytes("utf-8")
}
override def hashCode(): Int = {
toString.hashCode
}
override def equals(obj: scala.Any): Boolean = {
if (!obj.isInstanceOf[FilterPath]){
false
}
else{
val other = obj.asInstanceOf[FilterPath]
if (prefix != other.prefix) {
false
}
else {
super.equals(other)
}
}
}
}
object TPath {
def parseForFilter(path: String): Option[FilterPath] = {
val tokens = TName.parse(path)
parseForFilter(tokens)
}
def parseForFilter(tokens: Seq[TName]): Option[FilterPath] = {
tokens.foreach {
case _: TNameInvalid =>
return None
case n @ TNameMultiWildcard =>
// '#' can be only the last place
if (tokens.indexOf(n) != tokens.length - 1)
return None
case _ =>
}
// Local Subscription: $local/topic
// sub $local/topic
// pub topic
//
// Queue Subscription (Load balancing)
// sub $queue/topic
// pub topic
//
// Shared Subscription (Load balancing among the same group subscribers
// sub $share//topic
// pub topic
if (tokens.head.isLocalPrefix) {
Some(FilterPath(tokens.tail, Local))
}
else if (tokens.head.isQueuePrefix) {
Some(FilterPath(tokens.tail, Queue))
}
else if (tokens.head.isSharePrefix) {
val group = tokens.tail.head.name
Some(FilterPath(tokens.tail.tail, Share, group=Some(group)))
}
else {
Some(FilterPath(tokens, NoPrefix))
}
}
def parseForTopic(path: String): Option[TopicPath] = {
val tokens = TName.parse(path)
parseForTopic(tokens)
}
def parseForTopic(tokens: Seq[TName]): Option[TopicPath] = {
// [MQTT-4.7.1-1] The wildcard characters can be used in Topic Filters, but MUST NOT be used within a Topic Name
tokens.foreach {
case _: TNameInvalid =>
return None
case _: TNameWildcard =>
return None
case _ =>
}
Some(TopicPath(tokens))
}
}
object TPathTrie {
def apply[T]() = new TPathTrie[T]()
}
class TPathTrie[T] {
private class Node(token: TName) {
private val children: TrieMap[TName, Node] = TrieMap.empty
private val contexts: mutable.ListBuffer[T] = mutable.ListBuffer()
/**
* @return number of current number of contexts
*/
@tailrec
final def addDescendants(des: Seq[TName], context: T): Int = {
if (des.isEmpty) {
contexts.synchronized {
contexts += context
contexts.length
}
}
else {
val current = des.head
val child = children.synchronized {
children.get(current) match {
case Some(kid) =>
kid
case _ =>
val kid = new Node(current)
children.put(current, kid)
kid
}
}
child.addDescendants(des.tail, context)
}
}
final def removeDescendants(des: Seq[TName])(contextMatcher: T => Boolean): Int = {
if (des.isEmpty) {
contexts.synchronized {
contexts.find(contextMatcher) match {
case Some(ctx) => contexts -= ctx
case _ =>
}
contexts.length
}
}
else {
children.synchronized {
val current = des.head
children.get(current) match {
case Some(child) =>
val noOfContextsChildHas = child.removeDescendants(des.tail)(contextMatcher)
if (noOfContextsChildHas == 0) {
children.remove(current)
}
noOfContextsChildHas
case _ => // Question: can we silently ignore?
if (children.isEmpty)
contexts.length * -1 // ask parent not to remove me, i still have contexts
else
children.size * -1 // ask parent not to remove me, i still have children
}
}
}
}
/**
* @return 0 >= number of remaining contexts, < 0 means non-existing path
*/
final def removeDescendants(des: Seq[TName], context: T): Int = {
if (des.isEmpty) {
contexts.synchronized {
contexts -= context
contexts.length
}
}
else {
children.synchronized {
val current = des.head
children.get(current) match {
case Some(child) =>
val noOfContextsChildHas = child.removeDescendants(des.tail, context)
if (noOfContextsChildHas == 0) {
children.remove(current)
}
noOfContextsChildHas
case _ => // Question: can we silently ignore?
if (children.isEmpty)
contexts.length * -1 // ask parent not to remove me, i still have contexts
else
children.size * -1 // ask parent not to remove me, i still have children
}
}
}
}
/** this method is the key point of performance for delivering published message to subscribers */
final def matches(des: Seq[TName]): Seq[T] = {
if (des.isEmpty || this.token == TNameMultiWildcard) {
children.get(TNameMultiWildcard) match {
case Some(multi) =>
// filter that ends with '#'. e.g) filter 'sensor/#' should match with topic 'sensor'
multi.contexts ++ contexts
case None =>
contexts
}
}
else {
val current = des.head
val remains = des.tail
val exact = children.get(current).map(_.matches(remains))
val multi = children.get(TNameMultiWildcard).map(_.matches(remains))
val single = children.get(TNameSingleWildcard).map(_.matches(remains))
(exact :: multi :: single :: Nil).filterNot(_.isEmpty).flatMap(_.get)
}
}
final def snapshot: Seq[T] = {
Nil ++ contexts.seq ++ children.values.flatMap(_.snapshot)
}
final def dump(lvl: Int, sb: StringBuilder): Unit = {
if (lvl == 0) {
sb.append("\n")
}
else {
(0 until lvl).foldLeft(sb)((sb, _) => sb.append(" "))
sb.append("").append(if(token.name.length == 0) "''" else token.name).append("\t")
if (contexts.nonEmpty) sb.append("=> ")
contexts.foldLeft(sb)((sb, ctx) => sb.append("[").append(ctx.toString).append("] "))
sb.append("\n")
}
children.foreach{ case (_, child) =>
child.dump(lvl+1, sb)
}
}
}
private val root = new Node(TName(""))
def add(path: TPath, context: T): Int =
add(path.tokens, context)
def add(tokens: Seq[TName], context: T): Int =
root.addDescendants(tokens, context)
def remove(path: TPath, context: T): Int =
remove(path.tokens, context)
def remove(tokens: Seq[TName], context: T): Int =
root.removeDescendants(tokens, context)
def remove(path: TPath)(contextMatcher: T => Boolean): Int =
remove(path.tokens)(contextMatcher)
def remove(tokens: Seq[TName])(contextMatcher: T => Boolean): Int =
root.removeDescendants(tokens)(contextMatcher)
def matches(path: TPath): Seq[T] =
matches(path.tokens)
def matches(tokens: Seq[TName]): Seq[T] =
root.matches(tokens)
def snapshot: Seq[T] =
root.snapshot
def filter(matcher: T => Boolean): Seq[T] =
snapshot.filter(matcher)
/** only for debugging purpose */
def dump(sb: StringBuilder): Unit = {
root.dump(0, sb)
}
}
