72 lines
2.4 KiB
Java
72 lines
2.4 KiB
Java
package org.thoughtcrime.securesms.util;
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import androidx.annotation.NonNull;
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import org.thoughtcrime.securesms.recipients.RecipientId;
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import org.whispersystems.libsignal.util.guava.Optional;
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import org.whispersystems.signalservice.api.messages.SignalServiceContent;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Objects;
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/**
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* Sometimes a message that is referencing another message can arrive out of order. In these cases,
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* we want to temporarily hold on (i.e. keep a memory cache) to these messages and apply them after
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* we receive the referenced message.
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*/
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public final class EarlyMessageCache {
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private final LRUCache<MessageId, List<SignalServiceContent>> cache = new LRUCache<>(100);
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/**
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* @param targetSender The sender of the message this message depends on.
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* @param targetSentTimestamp The sent timestamp of the message this message depends on.
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*/
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public void store(@NonNull RecipientId targetSender, long targetSentTimestamp, @NonNull SignalServiceContent content) {
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MessageId messageId = new MessageId(targetSender, targetSentTimestamp);
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List<SignalServiceContent> contentList = cache.get(messageId);
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if (contentList == null) {
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contentList = new LinkedList<>();
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}
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contentList.add(content);
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cache.put(messageId, contentList);
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}
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/**
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* Returns and removes any content that is dependent on the provided message id.
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* @param sender The sender of the message in question.
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* @param sentTimestamp The sent timestamp of the message in question.
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*/
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public Optional<List<SignalServiceContent>> retrieve(@NonNull RecipientId sender, long sentTimestamp) {
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return Optional.fromNullable(cache.remove(new MessageId(sender, sentTimestamp)));
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}
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private static final class MessageId {
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private final RecipientId sender;
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private final long sentTimestamp;
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private MessageId(@NonNull RecipientId sender, long sentTimestamp) {
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this.sender = sender;
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this.sentTimestamp = sentTimestamp;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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MessageId messageId = (MessageId) o;
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return sentTimestamp == messageId.sentTimestamp &&
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Objects.equals(sender, messageId.sender);
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}
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@Override
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public int hashCode() {
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return Objects.hash(sentTimestamp, sender);
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}
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}
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}
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