Add some additional endpoints for PNP.

libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java

@@ -33,6 +33,7 @@ import org.whispersystems.signalservice.api.payments.CurrencyConversions;
 import org.whispersystems.signalservice.api.profiles.ProfileAndCredential;
 import org.whispersystems.signalservice.api.profiles.SignalServiceProfileWrite;
 import org.whispersystems.signalservice.api.push.ACI;
+import org.whispersystems.signalservice.api.push.AccountIdentifier;
 import org.whispersystems.signalservice.api.push.ContactTokenDetails;
 import org.whispersystems.signalservice.api.push.SignedPreKeyEntity;
 import org.whispersystems.signalservice.api.push.exceptions.NoContentException;
@@ -408,6 +409,13 @@ public class SignalServiceAccountManager {
     return this.pushServiceSocket.getCurrentSignedPreKey();
   }
 
+  /**
+   * @return True if the identifier corresponds to a registered user, otherwise false.
+   */
+  public boolean isIdentifierRegistered(AccountIdentifier identifier) throws IOException {
+    return pushServiceSocket.isIdentifierRegistered(identifier);
+  }
+
   /**
    * Checks whether a contact is currently registered with the server.
    *

libsignal/service/src/main/java/org/whispersystems/signalservice/api/push/ACI.java

@@ -16,12 +16,10 @@ import io.reactivex.rxjava3.annotations.NonNull;
  * An ACI is an "Account Identity". They're just UUIDs, but given multiple different things could be UUIDs, this wrapper exists to give us type safety around
  * this *specific type* of UUID.
  */
-public final class ACI {
+public final class ACI extends AccountIdentifier {
 
   public static final ACI UNKNOWN = ACI.from(UuidUtil.UNKNOWN_UUID);
 
-  private final UUID uuid;
-
   public static ACI from(UUID uuid) {
     return new ACI(uuid);
   }
@@ -72,11 +70,7 @@ public final class ACI {
   }
 
   private ACI(UUID uuid) {
-    this.uuid = uuid;
+    super(uuid);
-  }
-
-  public UUID uuid() {
-    return uuid;
   }
 
   public ByteString toByteString() {

libsignal/service/src/main/java/org/whispersystems/signalservice/api/push/AccountIdentifier.java

@@ -0,0 +1,24 @@
+package org.whispersystems.signalservice.api.push;
+
+import java.util.UUID;
+
+/**
+ * A wrapper around a UUID that represents an identifier for an account. Today, that is either an {@link ACI} or a {@link PNI}.
+ */
+public abstract class AccountIdentifier {
+
+  protected final UUID uuid;
+
+  protected AccountIdentifier(UUID uuid) {
+    this.uuid = uuid;
+  }
+
+  public UUID uuid() {
+    return uuid;
+  }
+
+  @Override
+  public String toString() {
+    return uuid.toString();
+  }
+}

libsignal/service/src/main/java/org/whispersystems/signalservice/api/push/PNI.java

@@ -0,0 +1,32 @@
+package org.whispersystems.signalservice.api.push;
+
+import java.util.UUID;
+
+/**
+ * A PNI is a "Phone Number Identity". They're just UUIDs, but given multiple different things could be UUIDs, this wrapper exists to give us type safety around
+ * this *specific type* of UUID.
+ */
+public final class PNI extends AccountIdentifier {
+
+  public static PNI from(UUID uuid) {
+    return new PNI(uuid);
+  }
+
+  private PNI(UUID uuid) {
+    super(uuid);
+  }
+
+  @Override
+  public int hashCode() {
+    return uuid.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object other) {
+    if (other instanceof PNI) {
+      return uuid.equals(((PNI) other).uuid);
+    } else {
+      return false;
+    }
+  }
+}

libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java

@@ -52,6 +52,7 @@ import org.whispersystems.signalservice.api.profiles.ProfileAndCredential;
 import org.whispersystems.signalservice.api.profiles.SignalServiceProfile;
 import org.whispersystems.signalservice.api.profiles.SignalServiceProfileWrite;
 import org.whispersystems.signalservice.api.push.ACI;
+import org.whispersystems.signalservice.api.push.AccountIdentifier;
 import org.whispersystems.signalservice.api.push.ContactTokenDetails;
 import org.whispersystems.signalservice.api.push.SignalServiceAddress;
 import org.whispersystems.signalservice.api.push.SignedPreKeyEntity;
@@ -86,7 +87,6 @@ import org.whispersystems.signalservice.api.subscriptions.SubscriptionLevels;
 import org.whispersystems.signalservice.api.util.CredentialsProvider;
 import org.whispersystems.signalservice.api.util.Tls12SocketFactory;
 import org.whispersystems.signalservice.api.util.TlsProxySocketFactory;
-import org.whispersystems.signalservice.api.util.UuidUtil;
 import org.whispersystems.signalservice.internal.configuration.SignalCdnUrl;
 import org.whispersystems.signalservice.internal.configuration.SignalProxy;
 import org.whispersystems.signalservice.internal.configuration.SignalServiceConfiguration;
@@ -192,6 +192,7 @@ public class PushServiceSocket {
   private static final String DELETE_USERNAME_PATH       = "/v1/accounts/username";
   private static final String DELETE_ACCOUNT_PATH        = "/v1/accounts/me";
   private static final String CHANGE_NUMBER_PATH         = "/v1/accounts/number";
+  private static final String IDENTIFIER_REGISTERED_PATH = "/v1/accounts/account/%s";
 
   private static final String PREKEY_METADATA_PATH      = "/v2/keys/";
   private static final String PREKEY_PATH               = "/v2/keys/%s";
@@ -332,7 +333,7 @@ public class PushServiceSocket {
   public ACI getOwnAci() throws IOException {
     String         body     = makeServiceRequest(WHO_AM_I, "GET", null);
     WhoAmIResponse response = JsonUtil.fromJson(body, WhoAmIResponse.class);
-    Optional<ACI>  aci      = ACI.parse(response.getUuid());
+    Optional<ACI>  aci      = ACI.parse(response.getAci());
 
     if (aci.isPresent()) {
       return aci.get();
@@ -345,6 +346,15 @@ public class PushServiceSocket {
     return JsonUtil.fromJson(makeServiceRequest(WHO_AM_I, "GET", null), WhoAmIResponse.class);
   }
 
+  public boolean isIdentifierRegistered(AccountIdentifier identifier) throws IOException {
+    try {
+      makeServiceRequestWithoutAuthentication(String.format(IDENTIFIER_REGISTERED_PATH, identifier.toString()), "HEAD", null);
+      return true;
+    } catch (NotFoundException e) {
+      return false;
+    }
+  }
+
   public CdshAuthResponse getCdshAuth() throws IOException {
     String body = makeServiceRequest(CDSH_AUTH, "GET", null);
     return JsonUtil.fromJsonResponse(body, CdshAuthResponse.class);

libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/WhoAmIResponse.java

@@ -6,13 +6,20 @@ public class WhoAmIResponse {
   @JsonProperty
   private String uuid;
 
+  @JsonProperty
+  private String pni;
+
   @JsonProperty
   private String number;
 
-  public String getUuid() {
+  public String getAci() {
     return uuid;
   }
 
+  public String getPni() {
+    return pni;
+  }
+
   public String getNumber() {
     return number;
   }