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Externalize Parcelable caching

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This commit is contained in:
Dominik Schürmann 2015-04-10 15:16:13 +02:00
parent a467480717
commit 702a77ccd1
2 changed files with 106 additions and 59 deletions
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70
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/results/OperationResult.java
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@ -33,75 +33,33 @@ import org.sufficientlysecure.keychain.ui.util.Notify.Showable;
import org.sufficientlysecure.keychain.ui.util.Notify.Style;
import org.sufficientlysecure.keychain.util.IterableIterator;
import org.sufficientlysecure.keychain.util.Log;
import org.sufficientlysecure.keychain.util.ParcelableCache;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
/** Represent the result of an operation.
/**
* Represent the result of an operation.
*
* This class holds a result and the log of an operation. It can be subclassed
* to include typed additional information specific to the operation. To keep
* the class structure (somewhat) simple, this class contains an exhaustive
* list (ie, enum) of all possible log types, which should in all cases be tied
* to string resource ids.
*
*/
public abstract class OperationResult implements Parcelable {
public static final String EXTRA_RESULT = "operation_result";
public static final UUID NULL_UUID = new UUID(0,0);
/**
* A HashMap of UUID:OperationLog which contains logs that we don't need
* to care about. This is used such that when we become parceled, we are
* well below the 1Mbit boundary that is specified.
* Instead of parceling the logs, they are cached to overcome the 1 MB boundary of
* Android's Binder. See ParcelableCache
*/
private static ConcurrentHashMap<UUID, OperationLog> dehydratedLogs;
private static ParcelableCache<OperationLog> logCache;
static {
// Static initializer for ConcurrentHashMap
dehydratedLogs = new ConcurrentHashMap<UUID,OperationLog>();
}
/**
* Dehydrate a log (such that it is available after deparcelization)
*
* Returns the NULL uuid (0) if you hand it null.
* @param log An OperationLog to dehydrate
* @return a UUID, the ticket for your dehydrated log
*
*/
private static UUID dehydrateLog(OperationLog log) {
if(log == null) {
return NULL_UUID;
}
else {
UUID ticket = UUID.randomUUID();
dehydratedLogs.put(ticket, log);
return ticket;
}
}
/***
* Rehydrate a log after going through parcelization, invalidating its place in the
* dehydration pool.
* This is used such that when parcelized, the parcel is no larger than 1mbit.
* @param ticket A UUID ticket that identifies the log in question.
* @return An OperationLog.
*/
private static OperationLog rehydrateLog(UUID ticket) {
// UUID.equals isn't well documented; we use compareTo instead.
if( NULL_UUID.compareTo(ticket) == 0 ) {
return null;
}
else {
OperationLog log = dehydratedLogs.get(ticket);
dehydratedLogs.remove(ticket);
return log;
}
logCache = new ParcelableCache<>();
}
/** Holds the overall result, the number specifying varying degrees of success:
@ -126,11 +84,8 @@ public abstract class OperationResult implements Parcelable {
public OperationResult(Parcel source) {
mResult = source.readInt();
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)
mLog = rehydrateLog(mTicket);
// get log out of cache based on UUID from source
mLog = logCache.readFromParcelAndGetFromCache(source);
}
public int getResult() {
@ -813,11 +768,8 @@ public abstract class OperationResult implements Parcelable {
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(mResult);
// Get a ticket for our log.
UUID mTicket = dehydrateLog(mLog);
// And write out the UUID most and least significant bits.
dest.writeLong(mTicket.getMostSignificantBits());
dest.writeLong(mTicket.getLeastSignificantBits());
// cache log and write UUID to dest
logCache.cacheAndWriteToParcel(mLog, dest);
}
public static class OperationLog implements Iterable<LogEntryParcel> {

95
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ParcelableCache.java Normal file
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@ -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());
}
}