X-Git-Url: https://git.pterodactylus.net/?p=Sone.git;a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fnet%2Fpterodactylus%2Fsone%2Fnotify%2FPostVisibilityFilter.java;fp=src%2Fmain%2Fjava%2Fnet%2Fpterodactylus%2Fsone%2Fnotify%2FPostVisibilityFilter.java;h=edcd148d1d8de973fe4911bd0cce842ea6e99923;hp=0000000000000000000000000000000000000000;hb=3da1daa6488c642430858a4baacc0aa986a6ebc1;hpb=9f562b1024a26cd8841447c6e29c3d89039d7a22

diff --git a/src/main/java/net/pterodactylus/sone/notify/PostVisibilityFilter.java b/src/main/java/net/pterodactylus/sone/notify/PostVisibilityFilter.java
new file mode 100644
index 0000000..edcd148
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+++ b/src/main/java/net/pterodactylus/sone/notify/PostVisibilityFilter.java
@@ -0,0 +1,98 @@
+package net.pterodactylus.sone.notify;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import javax.inject.Singleton;
+
+import net.pterodactylus.sone.data.Post;
+import net.pterodactylus.sone.data.Sone;
+import net.pterodactylus.sone.freenet.wot.OwnIdentity;
+import net.pterodactylus.sone.freenet.wot.Trust;
+import net.pterodactylus.util.notify.Notification;
+
+import com.google.common.base.Predicate;
+
+/**
+ * Filters {@link Notification}s involving {@link Post}s.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+@Singleton
+public class PostVisibilityFilter {
+
+	/**
+	 * Checks whether a post is visible to the given Sone. A post is not
+	 * considered visible if one of the following statements is true:
+	 * <ul>
+	 * <li>The post does not have a Sone.</li>
+	 * <li>The post’s {@link Post#getTime() time} is in the future.</li>
+	 * </ul>
+	 * <p>
+	 * If {@code post} is not {@code null} more checks are performed, and the
+	 * post will be invisible if:
+	 * </p>
+	 * <ul>
+	 * <li>The Sone of the post is not the given Sone, the given Sone does not
+	 * follow the post’s Sone, and the given Sone is not the recipient of the
+	 * post.</li>
+	 * <li>The trust relationship between the two Sones can not be retrieved.</li>
+	 * <li>The given Sone has explicitely assigned negative trust to the post’s
+	 * Sone.</li>
+	 * <li>The given Sone has not explicitely assigned negative trust to the
+	 * post’s Sone but the implicit trust is negative.</li>
+	 * </ul>
+	 * If none of these statements is true the post is considered visible.
+	 *
+	 * @param sone
+	 * 		The Sone that checks for a post’s visibility (may be
+	 * 		{@code null} to skip Sone-specific checks, such as trust)
+	 * @param post
+	 * 		The post to check for visibility
+	 * @return {@code true} if the post is considered visible, {@code false}
+	 * otherwise
+	 */
+	boolean isPostVisible(@Nullable Sone sone, @Nonnull Post post) {
+		checkNotNull(post, "post must not be null");
+		if (!post.isLoaded()) {
+			return false;
+		}
+		Sone postSone = post.getSone();
+		if (sone != null) {
+			Trust trust = postSone.getIdentity().getTrust((OwnIdentity) sone.getIdentity());
+			if (trust != null) {
+				if ((trust.getExplicit() != null) && (trust.getExplicit() < 0)) {
+					return false;
+				}
+				if ((trust.getExplicit() == null) && (trust.getImplicit() != null) && (trust.getImplicit() < 0)) {
+					return false;
+				}
+			} else {
+				/*
+				 * a null trust means that the trust updater has not yet
+				 * received a trust value for this relation. if we return false,
+				 * the post feed will stay empty until the trust updater has
+				 * received trust values. to prevent this we simply assume that
+				 * posts are visible if there is no trust.
+				 */
+			}
+			if ((!postSone.equals(sone)) && !sone.hasFriend(postSone.getId()) && !sone.getId().equals(post.getRecipientId().orNull())) {
+				return false;
+			}
+		}
+		return post.getTime() <= System.currentTimeMillis();
+	}
+
+	@Nonnull
+	public Predicate<Post> isVisible(@Nullable final Sone currentSone) {
+		return new Predicate<Post>() {
+			@Nonnull
+			@Override
+			public boolean apply(@Nullable Post post) {
+				return isPostVisible(currentSone, post);
+			}
+		};
+	}
+
+}