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author | Dominik Schürmann <dominik@dominikschuermann.de> | 2015-04-10 15:16:13 +0200 |
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committer | Dominik Schürmann <dominik@dominikschuermann.de> | 2015-04-10 15:16:13 +0200 |
commit | 702a77ccd1357dce5bd212b9761bec5044ec1280 (patch) | |
tree | 1a4bcab4637d6c60e76fb5feb06799dba006544c /OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java | |
parent | a4674807173bd32dd4f954893684ee7c88598454 (diff) | |
download | open-keychain-702a77ccd1357dce5bd212b9761bec5044ec1280.tar.gz open-keychain-702a77ccd1357dce5bd212b9761bec5044ec1280.tar.bz2 open-keychain-702a77ccd1357dce5bd212b9761bec5044ec1280.zip |
Externalize Parcelable caching
Diffstat (limited to 'OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java')
-rw-r--r-- | OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java new file mode 100644 index 000000000..4d723cb30 --- /dev/null +++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java @@ -0,0 +1,95 @@ +/* + * Copyright (C) 2015 Dominik Schürmann <dominik@dominikschuermann.de> + * + * 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.sufficientlysecure.keychain.util; + +import android.os.Parcel; + +import java.util.UUID; +import java.util.concurrent.ConcurrentHashMap; + +/** + * If Parcelables are above 1 MB, Android OS fails to send them via the Binder IPC: + * JavaBinder E !!! FAILED BINDER TRANSACTION !!! + * To overcome this issue this class allows to cache Parcelables, mapped by unique UUIDs, + * which are written to the parcel instead of the whole Parcelable. + */ +public class ParcelableCache<E extends Object> { + + private static final UUID NULL_UUID = new UUID(0, 0); + + /** + * A HashMap of UUID:Object + * This is used such that when we become parceled, we are + * well below the 1 MB boundary that is specified. + */ + private ConcurrentHashMap<UUID, E> dehydratedLogs = new ConcurrentHashMap<>(); + + /** + * Dehydrate a Parcelable (such that it is available after deparcelization) + * Returns the NULL uuid (0) if you hand it null. + * + * @param parcelable A Parcelable to dehydrate + * @return a UUID, the ticket for your dehydrated Parcelable + */ + private UUID dehydrateParcelable(E parcelable) { + if (parcelable == null) { + return NULL_UUID; + } else { + UUID ticket = UUID.randomUUID(); + dehydratedLogs.put(ticket, parcelable); + return ticket; + } + } + + /** + * Rehydrate a Parcelable after going through parcelization, + * invalidating its place in the dehydration pool. + * This is used such that when parcelized, the Parcelable is no larger than 1 MB. + * + * @param ticket A UUID ticket that identifies the log in question. + * @return An OperationLog. + */ + private E rehydrateParcelable(UUID ticket) { + // UUID.equals isn't well documented; we use compareTo instead. + if (NULL_UUID.compareTo(ticket) == 0) { + return null; + } else { + E parcelable = dehydratedLogs.get(ticket); + dehydratedLogs.remove(ticket); + return parcelable; + } + } + + public E readFromParcelAndGetFromCache(Parcel source) { + long mostSig = source.readLong(); + long leastSig = source.readLong(); + UUID mTicket = new UUID(mostSig, leastSig); + // fetch the dehydrated log out of storage (this removes it from the dehydration pool) + return rehydrateParcelable(mTicket); + } + + + public void cacheAndWriteToParcel(E parcelable, Parcel dest) { + // Get a ticket for our log. + UUID mTicket = dehydrateParcelable(parcelable); + // And write out the UUID most and least significant bits. + dest.writeLong(mTicket.getMostSignificantBits()); + dest.writeLong(mTicket.getLeastSignificantBits()); + } + +} |