Extract lib module

[signal-cli] / lib / src / main / java / org / asamk / signal / manager / groups / GroupUtils.java

diff --git a/lib/src/main/java/org/asamk/signal/manager/groups/GroupUtils.java b/lib/src/main/java/org/asamk/signal/manager/groups/GroupUtils.java
new file mode 100644 (file)
index 0000000..f56639e
--- /dev/null
+++ b/lib/src/main/java/org/asamk/signal/manager/groups/GroupUtils.java
@@ -0,0 +1,68 @@
+package org.asamk.signal.manager.groups;
+
+import org.asamk.signal.manager.storage.groups.GroupInfo;
+import org.asamk.signal.manager.storage.groups.GroupInfoV1;
+import org.asamk.signal.manager.storage.groups.GroupInfoV2;
+import org.signal.zkgroup.InvalidInputException;
+import org.signal.zkgroup.groups.GroupMasterKey;
+import org.signal.zkgroup.groups.GroupSecretParams;
+import org.whispersystems.libsignal.kdf.HKDFv3;
+import org.whispersystems.signalservice.api.messages.SignalServiceDataMessage;
+import org.whispersystems.signalservice.api.messages.SignalServiceGroup;
+import org.whispersystems.signalservice.api.messages.SignalServiceGroupContext;
+import org.whispersystems.signalservice.api.messages.SignalServiceGroupV2;
+
+public class GroupUtils {
+
+    public static void setGroupContext(
+            final SignalServiceDataMessage.Builder messageBuilder, final GroupInfo groupInfo
+    ) {
+        if (groupInfo instanceof GroupInfoV1) {
+            SignalServiceGroup group = SignalServiceGroup.newBuilder(SignalServiceGroup.Type.DELIVER)
+                    .withId(groupInfo.getGroupId().serialize())
+                    .build();
+            messageBuilder.asGroupMessage(group);
+        } else {
+            final GroupInfoV2 groupInfoV2 = (GroupInfoV2) groupInfo;
+            SignalServiceGroupV2 group = SignalServiceGroupV2.newBuilder(groupInfoV2.getMasterKey())
+                    .withRevision(groupInfoV2.getGroup() == null ? 0 : groupInfoV2.getGroup().getRevision())
+                    .build();
+            messageBuilder.asGroupMessage(group);
+        }
+    }
+
+    public static GroupId getGroupId(SignalServiceGroupContext context) {
+        if (context.getGroupV1().isPresent()) {
+            return GroupId.v1(context.getGroupV1().get().getGroupId());
+        } else if (context.getGroupV2().isPresent()) {
+            return getGroupIdV2(context.getGroupV2().get().getMasterKey());
+        } else {
+            return null;
+        }
+    }
+
+    public static GroupIdV2 getGroupIdV2(GroupSecretParams groupSecretParams) {
+        return GroupId.v2(groupSecretParams.getPublicParams().getGroupIdentifier().serialize());
+    }
+
+    public static GroupIdV2 getGroupIdV2(GroupMasterKey groupMasterKey) {
+        final GroupSecretParams groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
+        return getGroupIdV2(groupSecretParams);
+    }
+
+    public static GroupIdV2 getGroupIdV2(GroupIdV1 groupIdV1) {
+        final GroupSecretParams groupSecretParams = GroupSecretParams.deriveFromMasterKey(deriveV2MigrationMasterKey(
+                groupIdV1));
+        return getGroupIdV2(groupSecretParams);
+    }
+
+    private static GroupMasterKey deriveV2MigrationMasterKey(GroupIdV1 groupIdV1) {
+        try {
+            return new GroupMasterKey(new HKDFv3().deriveSecrets(groupIdV1.serialize(),
+                    "GV2 Migration".getBytes(),
+                    GroupMasterKey.SIZE));
+        } catch (InvalidInputException e) {
+            throw new AssertionError(e);
+        }
+    }
+}