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Add support for colliding name hashes to Js5Index

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Annoyingly, the 876 and latest RuneScape 3 cache both have collisions.

Signed-off-by: Graham <gpe@openrs2.dev>
Graham 4 years ago
parent f984f357d8
commit 4fdedf298b
2 changed files with 192 additions and 32 deletions
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  1. 67
      cache/src/main/java/dev/openrs2/cache/NamedEntryCollection.kt
  2. 153
      cache/src/test/java/dev/openrs2/cache/NamedEntryCollectionTest.kt

67
cache/src/main/java/dev/openrs2/cache/NamedEntryCollection.kt vendored
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@ -1,9 +1,12 @@
package dev.openrs2.cache
import dev.openrs2.util.krHashCode
import it.unimi.dsi.fastutil.ints.Int2IntMap
import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap
import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
import it.unimi.dsi.fastutil.ints.Int2ObjectMap
import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap
import it.unimi.dsi.fastutil.ints.IntAVLTreeSet
import it.unimi.dsi.fastutil.ints.IntSortedSet
import it.unimi.dsi.fastutil.ints.IntSortedSets
/**
* A specialist collection type entirely designed for use by the [Js5Index]
@ -34,17 +37,24 @@ import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
* none at all, but allowing a mixture in this implementation makes mutating
* the index simpler.
*
* This implementation does not allow multiple entries with the same name hash,
* and it throws an exception if it detects a collision. This differs from the
* client's implementation, which does not throw an exception and allows the
* colliding entry with the lowest ID to be referred to by the name.
* This implementation permits multiple entries to have the same name hash. In
* the event of a collision, the colliding entry with the lowest ID is returned
* from methods that look up an entry by its name hash. This implementation
* still behaves correctly if one of the colliding entries is removed: it will
* always return the entry with the next lowest ID.
*
* This is an edge case that is unlikely to be hit in practice: the 550 cache
* has no collisions, and the 876 cache only has a single collision (the hash
* for the empty string).
*/
public abstract class NamedEntryCollection<T : NamedEntry>(
private val entryConstructor: (NamedEntryCollection<T>, Int) -> T
) : MutableIterable<T> {
private var singleEntry: T? = null
private var entries: Int2ObjectAVLTreeMap<T>? = null
private var nameHashTable: Int2IntMap? = null
// XXX(gpe): unfortunately fastutil doesn't have a multimap type
private var nameHashTable: Int2ObjectMap<IntSortedSet>? = null
public val size: Int
get() {
@ -116,9 +126,9 @@ public abstract class NamedEntryCollection<T : NamedEntry>(
}
val nameHashTable = nameHashTable ?: return null
val id = nameHashTable[nameHash]
return if (id != -1) {
get(id) ?: throw IllegalStateException()
val ids = nameHashTable.getOrDefault(nameHash, IntSortedSets.EMPTY_SET)
return if (ids.isNotEmpty()) {
get(ids.firstInt()) ?: throw IllegalStateException()
} else {
null
}
@ -150,9 +160,8 @@ public abstract class NamedEntryCollection<T : NamedEntry>(
entries[singleEntry.id] = singleEntry
if (singleEntry.nameHash != -1) {
val nameHashTable = Int2IntOpenHashMap()
nameHashTable.defaultReturnValue(-1)
nameHashTable[singleEntry.nameHash] = singleEntry.id
val nameHashTable = Int2ObjectOpenHashMap<IntSortedSet>()
nameHashTable[singleEntry.nameHash] = IntSortedSets.singleton(singleEntry.id)
this.nameHashTable = nameHashTable
}
}
@ -224,18 +233,31 @@ public abstract class NamedEntryCollection<T : NamedEntry>(
var nameHashTable = nameHashTable
if (nameHashTable != null && prevNameHash != -1) {
val set = nameHashTable.get(prevNameHash)
check(set != null && set.contains(id))
if (set.size > 1) {
set.remove(id)
} else {
nameHashTable.remove(prevNameHash)
}
}
if (newNameHash != -1) {
if (nameHashTable == null) {
nameHashTable = Int2IntOpenHashMap()
nameHashTable.defaultReturnValue(-1)
nameHashTable = Int2ObjectOpenHashMap()
}
val prevId = nameHashTable.put(newNameHash, id)
check(prevId == -1) {
"Name hash collision: $newNameHash is already used by entry $prevId"
val set = nameHashTable[newNameHash]
when {
set == null -> nameHashTable[newNameHash] = IntSortedSets.singleton(id)
set.size == 1 -> {
val newSet = IntAVLTreeSet()
newSet.add(set.firstInt())
newSet.add(id)
nameHashTable[newNameHash] = newSet
}
else -> set.add(id)
}
this.nameHashTable = nameHashTable
@ -262,14 +284,7 @@ public abstract class NamedEntryCollection<T : NamedEntry>(
return
}
val nameHashTable = nameHashTable ?: return
if (entry.nameHash != -1) {
nameHashTable.remove(entry.nameHash)
if (nameHashTable.isEmpty()) {
this.nameHashTable = null
}
}
rename(entry.id, entry.nameHash, -1)
}
override fun iterator(): MutableIterator<T> {

153
cache/src/test/java/dev/openrs2/cache/NamedEntryCollectionTest.kt vendored
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@ -736,11 +736,156 @@ object NamedEntryCollectionTest {
@Test
fun testNameHashCollision() {
val collection = TestCollection()
collection.createOrGet("hello")
val entry = collection.createOrGet(1)
assertThrows<IllegalStateException> {
entry.setName("hello")
val entry0 = collection.createOrGet(0)
val entry1 = collection.createOrGet(1)
val entry2 = collection.createOrGet(2)
entry0.setName("hello")
entry1.setName("hello")
entry2.setName("hello")
assertEquals(entry0, collection["hello"])
entry0.clearName()
assertEquals(entry1, collection["hello"])
entry1.clearName()
assertEquals(entry2, collection["hello"])
entry2.clearName()
assertNull(collection["hello"])
}
@Test
fun testNameHashCollisionOppositeOrder() {
val collection = TestCollection()
val entry0 = collection.createOrGet(0)
val entry1 = collection.createOrGet(1)
val entry2 = collection.createOrGet(2)
entry2.setName("hello")
entry1.setName("hello")
entry0.setName("hello")
assertEquals(entry0, collection["hello"])
entry2.clearName()
assertEquals(entry0, collection["hello"])
entry1.clearName()
assertEquals(entry0, collection["hello"])
entry0.clearName()
assertNull(collection["hello"])
}
@Test
fun testNameHashCollisionRemove() {
val collection = TestCollection()
val entry0 = collection.createOrGet(0)
val entry1 = collection.createOrGet(1)
val entry2 = collection.createOrGet(2)
entry0.setName("hello")
entry1.setName("hello")
entry2.setName("hello")
assertEquals(entry0, collection["hello"])
entry0.remove()
assertEquals(entry1, collection["hello"])
entry1.remove()
assertEquals(entry2, collection["hello"])
entry2.remove()
assertNull(collection["hello"])
}
@Test
fun testNameHashCollisionOppositeOrderRemove() {
val collection = TestCollection()
val entry0 = collection.createOrGet(0)
val entry1 = collection.createOrGet(1)
val entry2 = collection.createOrGet(2)
entry2.setName("hello")
entry1.setName("hello")
entry0.setName("hello")
assertEquals(entry0, collection["hello"])
entry2.remove()
assertEquals(entry0, collection["hello"])
entry1.remove()
assertEquals(entry0, collection["hello"])
entry0.remove()
assertNull(collection["hello"])
}
@Test
fun testNameHashCollisionRename() {
val collection = TestCollection()
val entry0 = collection.createOrGet(0)
val entry1 = collection.createOrGet(1)
val entry2 = collection.createOrGet(2)
entry0.setName("hello")
entry1.setName("hello")
entry2.setName("hello")
assertEquals(entry0, collection["hello"])
entry0.setName("entry0")
assertEquals(entry0, collection["entry0"])
assertEquals(entry1, collection["hello"])
entry1.setName("entry1")
assertEquals(entry0, collection["entry0"])
assertEquals(entry1, collection["entry1"])
assertEquals(entry2, collection["hello"])
entry2.setName("entry2")
assertEquals(entry0, collection["entry0"])
assertEquals(entry1, collection["entry1"])
assertEquals(entry2, collection["entry2"])
assertNull(collection["hello"])
}
@Test
fun testNameHashCollisionOppositeOrderRename() {
val collection = TestCollection()
val entry0 = collection.createOrGet(0)
val entry1 = collection.createOrGet(1)
val entry2 = collection.createOrGet(2)
entry2.setName("hello")
entry1.setName("hello")
entry0.setName("hello")
assertEquals(entry0, collection["hello"])
entry2.setName("entry2")
assertEquals(entry2, collection["entry2"])
assertEquals(entry0, collection["hello"])
entry1.setName("entry1")
assertEquals(entry1, collection["entry1"])
assertEquals(entry2, collection["entry2"])
assertEquals(entry0, collection["hello"])
entry0.setName("entry0")
assertEquals(entry0, collection["entry0"])
assertEquals(entry1, collection["entry1"])
assertEquals(entry2, collection["entry2"])
assertNull(collection["hello"])
}
}

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