Introduce V2 API for PreKey updates and requests.

1) A /v2/keys controller.

2) Separate wire protocol PreKey POJOs from database PreKey
   objects.

3) Separate wire protocol PreKey submission and response POJOs.

4) Introduce a new update/response JSON format for /v2/keys.

src/main/java/org/whispersystems/textsecuregcm/controllers/KeysControllerV2.java

@@ -0,0 +1,147 @@
+/**
+ * Copyright (C) 2014 Open Whisper Systems
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.whispersystems.textsecuregcm.controllers;
+
+
+import com.codahale.metrics.annotation.Timed;
+import com.google.common.base.Optional;
+import org.whispersystems.textsecuregcm.entities.DeviceKey;
+import org.whispersystems.textsecuregcm.entities.PreKeyResponseItemV2;
+import org.whispersystems.textsecuregcm.entities.PreKeyResponseV2;
+import org.whispersystems.textsecuregcm.entities.PreKeyStateV2;
+import org.whispersystems.textsecuregcm.entities.PreKeyV2;
+import org.whispersystems.textsecuregcm.federation.FederatedClientManager;
+import org.whispersystems.textsecuregcm.federation.NoSuchPeerException;
+import org.whispersystems.textsecuregcm.limits.RateLimiters;
+import org.whispersystems.textsecuregcm.storage.Account;
+import org.whispersystems.textsecuregcm.storage.AccountsManager;
+import org.whispersystems.textsecuregcm.storage.Device;
+import org.whispersystems.textsecuregcm.storage.KeyRecord;
+import org.whispersystems.textsecuregcm.storage.Keys;
+
+import javax.validation.Valid;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.GET;
+import javax.ws.rs.PUT;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.Produces;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.Response;
+import java.util.LinkedList;
+import java.util.List;
+
+import io.dropwizard.auth.Auth;
+
+@Path("/v2/keys")
+public class KeysControllerV2 extends KeysController {
+
+  public KeysControllerV2(RateLimiters rateLimiters, Keys keys, AccountsManager accounts,
+                          FederatedClientManager federatedClientManager)
+  {
+    super(rateLimiters, keys, accounts, federatedClientManager);
+  }
+
+
+  @Timed
+  @PUT
+  @Consumes(MediaType.APPLICATION_JSON)
+  public void setKeys(@Auth Account account, @Valid PreKeyStateV2 preKeys)  {
+    Device  device        = account.getAuthenticatedDevice().get();
+    boolean updateAccount = false;
+
+    if (!preKeys.getDeviceKey().equals(device.getDeviceKey())) {
+      device.setDeviceKey(preKeys.getDeviceKey());
+      updateAccount = true;
+    }
+
+    if (!preKeys.getIdentityKey().equals(account.getIdentityKey())) {
+      account.setIdentityKey(preKeys.getIdentityKey());
+      updateAccount = true;
+    }
+
+    if (updateAccount) {
+      accounts.update(account);
+    }
+
+    keys.store(account.getNumber(), device.getId(), preKeys.getPreKeys(), preKeys.getLastResortKey());
+  }
+
+  @Timed
+  @PUT
+  @Path("/device")
+  @Consumes(MediaType.APPLICATION_JSON)
+  public void setDeviceKey(@Auth Account account, @Valid DeviceKey deviceKey) {
+    Device device = account.getAuthenticatedDevice().get();
+    device.setDeviceKey(deviceKey);
+    accounts.update(account);
+  }
+
+  @Timed
+  @GET
+  @Path("/{number}/{device_id}")
+  @Produces(MediaType.APPLICATION_JSON)
+  public Optional<PreKeyResponseV2> getDeviceKey(@Auth                   Account account,
+                                                 @PathParam("number")    String number,
+                                                 @PathParam("device_id") String deviceId,
+                                                 @QueryParam("relay")    Optional<String> relay)
+      throws RateLimitExceededException
+  {
+    try {
+      if (account.isRateLimited()) {
+        rateLimiters.getPreKeysLimiter().validate(account.getNumber() +  "__" + number + "." + deviceId);
+      }
+
+      if (relay.isPresent()) {
+        return federatedClientManager.getClient(relay.get()).getKeysV2(number, deviceId);
+      }
+
+      TargetKeys                 targetKeys  = getLocalKeys(number, deviceId);
+      Account                    destination = targetKeys.getDestination();
+      List<PreKeyResponseItemV2> devices     = new LinkedList<>();
+
+      for (Device device : destination.getDevices()) {
+        if (device.isActive() && (deviceId.equals("*") || device.getId() == Long.parseLong(deviceId))) {
+          DeviceKey deviceKey = device.getDeviceKey();
+          PreKeyV2  preKey    = null;
+
+          if (targetKeys.getKeys().isPresent()) {
+            for (KeyRecord keyRecord : targetKeys.getKeys().get()) {
+              if (keyRecord.getDeviceId() == device.getId()) {
+                preKey = new PreKeyV2(keyRecord.getKeyId(), keyRecord.getPublicKey());
+              }
+            }
+          }
+
+          if (deviceKey != null || preKey != null) {
+            devices.add(new PreKeyResponseItemV2(device.getId(), device.getRegistrationId(), deviceKey, preKey));
+          }
+        }
+      }
+
+      if (devices.isEmpty()) return Optional.absent();
+      else                   return Optional.of(new PreKeyResponseV2(destination.getIdentityKey(), devices));
+    } catch (NoSuchPeerException | NoSuchUserException e) {
+      throw new WebApplicationException(Response.status(404).build());
+    }
+  }
+
+
+
+}