Refactor accounts

HMCLCore/src/main/java/org/jackhuang/hmcl/auth/authlibinjector/AuthlibInjectorAccount.java

@@ -31,6 +31,7 @@ import org.jackhuang.hmcl.util.NetworkUtils;
 
 import java.util.Base64;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.UUID;
 import java.util.logging.Level;
@@ -110,4 +111,16 @@ public class AuthlibInjectorAccount extends YggdrasilAccount {
         return server;
     }
 
+    @Override
+    public int hashCode() {
+        return Objects.hash(super.hashCode(), server.hashCode());
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof AuthlibInjectorAccount))
+            return false;
+        AuthlibInjectorAccount another = (AuthlibInjectorAccount) obj;
+        return super.equals(another) && server.equals(another.server);
+    }
 }

HMCLCore/src/main/java/org/jackhuang/hmcl/auth/offline/OfflineAccount.java

@@ -105,4 +105,17 @@ public class OfflineAccount extends Account {
                 .append("uuid", uuid)
                 .toString();
     }
+
+    @Override
+    public int hashCode() {
+        return username.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof OfflineAccount))
+            return false;
+        OfflineAccount another = (OfflineAccount) obj;
+        return username.equals(another.username);
+    }
 }

HMCLCore/src/main/java/org/jackhuang/hmcl/auth/yggdrasil/YggdrasilAccount.java

@@ -169,4 +169,16 @@ public class YggdrasilAccount extends Account {
         return "YggdrasilAccount[username=" + getUsername() + "]";
     }
 
+    @Override
+    public int hashCode() {
+        return characterUUID.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof YggdrasilAccount))
+            return false;
+        YggdrasilAccount another = (YggdrasilAccount) obj;
+        return characterUUID.equals(another.characterUUID);
+    }
 }

HMCLCore/src/main/java/org/jackhuang/hmcl/util/MappedObservableList.java

@@ -0,0 +1,160 @@
+/*
+ * Hello Minecraft! Launcher.
+ * Copyright (C) 2018  huangyuhui <huanghongxun2008@126.com>
+ *
+ * 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 org.jackhuang.hmcl.util;
+
+import static java.util.stream.Collectors.toCollection;
+import static javafx.collections.FXCollections.unmodifiableObservableList;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+
+import javafx.beans.InvalidationListener;
+import javafx.beans.Observable;
+import javafx.collections.FXCollections;
+import javafx.collections.ListChangeListener;
+import javafx.collections.ObservableList;
+import javafx.collections.WeakListChangeListener;
+
+/**
+ * @author yushijinhun
+ */
+public final class MappedObservableList {
+    private MappedObservableList() {
+    }
+
+    private static class ReferenceHolder implements InvalidationListener {
+        @SuppressWarnings("unused")
+        private Object ref;
+
+        ReferenceHolder(Object ref) {
+            this.ref = ref;
+        }
+
+        @Override
+        public void invalidated(Observable observable) {
+            // no-op
+        }
+    }
+
+    private static class MappedObservableListUpdater<T, U> implements ListChangeListener<T> {
+        private ObservableList<T> origin;
+        private ObservableList<U> target;
+        private Function<T, U> mapper;
+
+        // If we directly synchronize changes to target, each operation on target will cause a event to be fired.
+        // So we first write changes to buffer. After all the changes are processed, we use target.setAll to synchronize the changes.
+        private List<U> buffer;
+
+        MappedObservableListUpdater(ObservableList<T> origin, ObservableList<U> target, Function<T, U> mapper) {
+            this.origin = origin;
+            this.target = target;
+            this.mapper = mapper;
+            this.buffer = new ArrayList<>(target);
+        }
+
+        @Override
+        public void onChanged(Change<? extends T> change) {
+            // cache removed elements to reduce calls to mapper
+            Map<T, LinkedList<U>> cache = new HashMap<>();
+
+            while (change.next()) {
+                int from = change.getFrom();
+                int to = change.getTo();
+
+                if (change.wasPermutated()) {
+                    @SuppressWarnings("unchecked")
+                    U[] temp = (U[]) new Object[to - from];
+                    for (int i = 0; i < temp.length; i++) {
+                        temp[i] = buffer.get(from + i);
+                    }
+
+                    for (int idx = from; idx < to; idx++) {
+                        buffer.set(change.getPermutation(idx), temp[idx - from]);
+                    }
+                } else {
+                    if (change.wasRemoved()) {
+                        List<? extends T> originRemoved = change.getRemoved();
+                        List<U> targetRemoved = buffer.subList(from, from + originRemoved.size());
+                        for (int i = 0; i < targetRemoved.size(); i++) {
+                            pushCache(cache, originRemoved.get(i), targetRemoved.get(i));
+                        }
+                        targetRemoved.clear();
+                    }
+                    if (change.wasAdded()) {
+                        @SuppressWarnings("unchecked")
+                        U[] toAdd = (U[]) new Object[to - from];
+                        for (int i = 0; i < toAdd.length; i++) {
+                            toAdd[i] = map(cache, origin.get(from + i));
+                        }
+                        buffer.addAll(from, Arrays.asList(toAdd));
+                    }
+                }
+            }
+            target.setAll(buffer);
+        }
+
+        private void pushCache(Map<T, LinkedList<U>> cache, T key, U value) {
+            cache.computeIfAbsent(key, any -> new LinkedList<>())
+                    .push(value);
+        }
+
+        private U map(Map<T, LinkedList<U>> cache, T key) {
+            LinkedList<U> stack = cache.get(key);
+            if (stack != null && !stack.isEmpty()) {
+                return stack.pop();
+            }
+            return mapper.apply(key);
+        }
+    }
+
+    /**
+     * This methods creates a mapping of {@code origin}, using {@code mapper} as the converter.
+     *
+     * If an item is added to {@code origin}, {@code mapper} will be invoked to create a corresponding item, which will also be added to the returned {@code ObservableList}.
+     * If an item is removed from {@code origin}, the corresponding item in the returned {@code ObservableList} will also be removed.
+     * If {@code origin} is permutated, the returned {@code ObservableList} will also be permutated in the same way.
+     *
+     * The returned {@code ObservableList} is unmodifiable.
+     */
+    public static <T, U> ObservableList<U> create(ObservableList<T> origin, Function<T, U> mapper) {
+        // create a already-synchronized target ObservableList<U>
+        ObservableList<U> target = origin.stream()
+                .map(mapper)
+                .collect(toCollection(FXCollections::observableArrayList));
+
+        // then synchronize further changes to target
+        ListChangeListener<T> listener = new MappedObservableListUpdater<>(origin, target, mapper);
+
+        // let target hold a reference to listener to prevent listener being garbage-collected before target is garbage-collected
+        target.addListener(new ReferenceHolder(listener));
+
+        // let origin hold a weak reference to listener, so that target can be garbage-collected when it's no longer used
+        origin.addListener(new WeakListChangeListener<>(listener));
+
+        // ref graph:
+        // target ------> listener <-weak- origin
+        //        <------          ------>
+
+        return unmodifiableObservableList(target);
+    }
+}