🔀 Merge branch 'release/v82'

[Sone.git] / src / main / kotlin / net / pterodactylus / sone / freenet / wot / IdentityChangeDetector.kt

diff --git a/src/main/kotlin/net/pterodactylus/sone/freenet/wot/IdentityChangeDetector.kt b/src/main/kotlin/net/pterodactylus/sone/freenet/wot/IdentityChangeDetector.kt
new file mode 100644 (file)
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+++ b/src/main/kotlin/net/pterodactylus/sone/freenet/wot/IdentityChangeDetector.kt
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+/*
+ * Sone - IdentityChangeDetector.kt - Copyright © 2013–2020 David Roden
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.sone.freenet.wot
+
+/**
+ * Detects changes between two lists of [Identity]s. The detector can find
+ * added and removed identities, and for identities that exist in both list
+ * their contexts and properties are checked for added, removed, or (in case of
+ * properties) changed values.
+ */
+class IdentityChangeDetector(oldIdentities: Collection<Identity>) {
+
+       private val oldIdentities: Map<String, Identity> = oldIdentities.associateBy { it.id }
+       var onNewIdentity: IdentityProcessor? = null
+       var onRemovedIdentity: IdentityProcessor? = null
+       var onChangedIdentity: IdentityProcessor? = null
+       var onUnchangedIdentity: IdentityProcessor? = null
+
+       fun detectChanges(newIdentities: Collection<Identity>) {
+               onRemovedIdentity.notify(oldIdentities.values.filter { it !in newIdentities })
+               onNewIdentity.notify(newIdentities.filter { it !in oldIdentities.values })
+               onChangedIdentity.notify(newIdentities.filter { it.id in oldIdentities }.filter { identityHasChanged(oldIdentities[it.id]!!, it) })
+               onUnchangedIdentity.notify(newIdentities.filter { it.id in oldIdentities }.filterNot { identityHasChanged(oldIdentities[it.id]!!, it) })
+       }
+
+       private fun identityHasChanged(oldIdentity: Identity, newIdentity: Identity?) =
+                       identityHasNewContexts(oldIdentity, newIdentity!!)
+                                       || identityHasRemovedContexts(oldIdentity, newIdentity)
+                                       || identityHasNewProperties(oldIdentity, newIdentity)
+                                       || identityHasRemovedProperties(oldIdentity, newIdentity)
+                                       || identityHasChangedProperties(oldIdentity, newIdentity)
+
+       private fun identityHasNewContexts(oldIdentity: Identity, newIdentity: Identity) =
+                       newIdentity.contexts.any { it !in oldIdentity.contexts }
+
+       private fun identityHasRemovedContexts(oldIdentity: Identity, newIdentity: Identity) =
+                       oldIdentity.contexts.any { it !in newIdentity.contexts }
+
+       private fun identityHasNewProperties(oldIdentity: Identity, newIdentity: Identity) =
+                       newIdentity.properties.keys.any { it !in oldIdentity.properties }
+
+       private fun identityHasRemovedProperties(oldIdentity: Identity, newIdentity: Identity) =
+                       oldIdentity.properties.keys.any { it !in newIdentity.properties }
+
+       private fun identityHasChangedProperties(oldIdentity: Identity, newIdentity: Identity) =
+                       oldIdentity.properties.entries.any { newIdentity.properties[it.key] != it.value }
+
+}
+
+typealias IdentityProcessor = (Identity) -> Unit
+
+private fun IdentityProcessor?.notify(identities: Iterable<Identity>) =
+               this?.let { identities.forEach(this::invoke) }