| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * 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 android.content.res; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.compat.annotation.UnsupportedAppUsage; |
| import android.content.pm.ActivityInfo.Config; |
| import android.content.res.Resources.Theme; |
| import android.content.res.Resources.ThemeKey; |
| import android.util.ArrayMap; |
| import android.util.LongSparseArray; |
| |
| import java.lang.ref.WeakReference; |
| |
| /** |
| * Data structure used for caching data against themes. |
| * |
| * @param <T> type of data to cache |
| */ |
| abstract class ThemedResourceCache<T> { |
| @UnsupportedAppUsage |
| private ArrayMap<ThemeKey, LongSparseArray<WeakReference<T>>> mThemedEntries; |
| private LongSparseArray<WeakReference<T>> mUnthemedEntries; |
| private LongSparseArray<WeakReference<T>> mNullThemedEntries; |
| |
| /** |
| * Adds a new theme-dependent entry to the cache. |
| * |
| * @param key a key that uniquely identifies the entry |
| * @param theme the theme against which this entry was inflated, or |
| * {@code null} if the entry has no theme applied |
| * @param entry the entry to cache |
| */ |
| public void put(long key, @Nullable Theme theme, @NonNull T entry) { |
| put(key, theme, entry, true); |
| } |
| |
| /** |
| * Adds a new entry to the cache. |
| * |
| * @param key a key that uniquely identifies the entry |
| * @param theme the theme against which this entry was inflated, or |
| * {@code null} if the entry has no theme applied |
| * @param entry the entry to cache |
| * @param usesTheme {@code true} if the entry is affected theme changes, |
| * {@code false} otherwise |
| */ |
| public void put(long key, @Nullable Theme theme, @NonNull T entry, boolean usesTheme) { |
| if (entry == null) { |
| return; |
| } |
| |
| synchronized (this) { |
| final LongSparseArray<WeakReference<T>> entries; |
| if (!usesTheme) { |
| entries = getUnthemedLocked(true); |
| } else { |
| entries = getThemedLocked(theme, true); |
| } |
| if (entries != null) { |
| entries.put(key, new WeakReference<>(entry)); |
| } |
| } |
| } |
| |
| /** |
| * Returns an entry from the cache. |
| * |
| * @param key a key that uniquely identifies the entry |
| * @param theme the theme where the entry will be used |
| * @return a cached entry, or {@code null} if not in the cache |
| */ |
| @Nullable |
| public T get(long key, @Nullable Theme theme) { |
| // The themed (includes null-themed) and unthemed caches are mutually |
| // exclusive, so we'll give priority to whichever one we think we'll |
| // hit first. Since most of the framework drawables are themed, that's |
| // probably going to be the themed cache. |
| synchronized (this) { |
| final LongSparseArray<WeakReference<T>> themedEntries = getThemedLocked(theme, false); |
| if (themedEntries != null) { |
| final WeakReference<T> themedEntry = themedEntries.get(key); |
| if (themedEntry != null) { |
| return themedEntry.get(); |
| } |
| } |
| |
| final LongSparseArray<WeakReference<T>> unthemedEntries = getUnthemedLocked(false); |
| if (unthemedEntries != null) { |
| final WeakReference<T> unthemedEntry = unthemedEntries.get(key); |
| if (unthemedEntry != null) { |
| return unthemedEntry.get(); |
| } |
| } |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Prunes cache entries that have been invalidated by a configuration |
| * change. |
| * |
| * @param configChanges a bitmask of configuration changes |
| */ |
| @UnsupportedAppUsage |
| public void onConfigurationChange(@Config int configChanges) { |
| prune(configChanges); |
| } |
| |
| /** |
| * Returns whether a cached entry has been invalidated by a configuration |
| * change. |
| * |
| * @param entry a cached entry |
| * @param configChanges a non-zero bitmask of configuration changes |
| * @return {@code true} if the entry is invalid, {@code false} otherwise |
| */ |
| protected abstract boolean shouldInvalidateEntry(@NonNull T entry, int configChanges); |
| |
| /** |
| * Returns the cached data for the specified theme, optionally creating a |
| * new entry if one does not already exist. |
| * |
| * @param t the theme for which to return cached data |
| * @param create {@code true} to create an entry if one does not already |
| * exist, {@code false} otherwise |
| * @return the cached data for the theme, or {@code null} if the cache is |
| * empty and {@code create} was {@code false} |
| */ |
| @Nullable |
| private LongSparseArray<WeakReference<T>> getThemedLocked(@Nullable Theme t, boolean create) { |
| if (t == null) { |
| if (mNullThemedEntries == null && create) { |
| mNullThemedEntries = new LongSparseArray<>(1); |
| } |
| return mNullThemedEntries; |
| } |
| |
| if (mThemedEntries == null) { |
| if (create) { |
| mThemedEntries = new ArrayMap<>(1); |
| } else { |
| return null; |
| } |
| } |
| |
| final ThemeKey key = t.getKey(); |
| LongSparseArray<WeakReference<T>> cache = mThemedEntries.get(key); |
| if (cache == null && create) { |
| cache = new LongSparseArray<>(1); |
| |
| final ThemeKey keyClone = key.clone(); |
| mThemedEntries.put(keyClone, cache); |
| } |
| |
| return cache; |
| } |
| |
| /** |
| * Returns the theme-agnostic cached data. |
| * |
| * @param create {@code true} to create an entry if one does not already |
| * exist, {@code false} otherwise |
| * @return the theme-agnostic cached data, or {@code null} if the cache is |
| * empty and {@code create} was {@code false} |
| */ |
| @Nullable |
| private LongSparseArray<WeakReference<T>> getUnthemedLocked(boolean create) { |
| if (mUnthemedEntries == null && create) { |
| mUnthemedEntries = new LongSparseArray<>(1); |
| } |
| return mUnthemedEntries; |
| } |
| |
| /** |
| * Prunes cache entries affected by configuration changes or where weak |
| * references have expired. |
| * |
| * @param configChanges a bitmask of configuration changes, or {@code 0} to |
| * simply prune missing weak references |
| * @return {@code true} if the cache is completely empty after pruning |
| */ |
| private boolean prune(@Config int configChanges) { |
| synchronized (this) { |
| if (mThemedEntries != null) { |
| for (int i = mThemedEntries.size() - 1; i >= 0; i--) { |
| if (pruneEntriesLocked(mThemedEntries.valueAt(i), configChanges)) { |
| mThemedEntries.removeAt(i); |
| } |
| } |
| } |
| |
| pruneEntriesLocked(mNullThemedEntries, configChanges); |
| pruneEntriesLocked(mUnthemedEntries, configChanges); |
| |
| return mThemedEntries == null && mNullThemedEntries == null |
| && mUnthemedEntries == null; |
| } |
| } |
| |
| private boolean pruneEntriesLocked(@Nullable LongSparseArray<WeakReference<T>> entries, |
| @Config int configChanges) { |
| if (entries == null) { |
| return true; |
| } |
| |
| for (int i = entries.size() - 1; i >= 0; i--) { |
| final WeakReference<T> ref = entries.valueAt(i); |
| if (ref == null || pruneEntryLocked(ref.get(), configChanges)) { |
| entries.removeAt(i); |
| } |
| } |
| |
| return entries.size() == 0; |
| } |
| |
| private boolean pruneEntryLocked(@Nullable T entry, @Config int configChanges) { |
| return entry == null || (configChanges != 0 |
| && shouldInvalidateEntry(entry, configChanges)); |
| } |
| } |