Initial multi device support refactoring.

1) Store account data as a json type, which includes all
   devices in a single object.

2) Simplify message delivery logic.

3) Make federated calls a pass through to standard controllers.

4) Simplify key retrieval logic.

src/main/java/org/whispersystems/textsecuregcm/entities/CryptoEncodingException.java

@@ -0,0 +1,13 @@
+package org.whispersystems.textsecuregcm.entities;
+
+public class CryptoEncodingException extends Exception {
+
+  public CryptoEncodingException(String s) {
+    super(s);
+  }
+
+  public CryptoEncodingException(Exception e) {
+    super(e);
+  }
+
+}

src/main/java/org/whispersystems/textsecuregcm/entities/DeviceResponse.java

@@ -0,0 +1,21 @@
+package org.whispersystems.textsecuregcm.entities;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.common.annotations.VisibleForTesting;
+
+public class DeviceResponse {
+
+  @JsonProperty
+  private long deviceId;
+
+  @VisibleForTesting
+  public DeviceResponse() {}
+
+  public DeviceResponse(long deviceId) {
+    this.deviceId = deviceId;
+  }
+
+  public long getDeviceId() {
+    return deviceId;
+  }
+}

src/main/java/org/whispersystems/textsecuregcm/entities/EncryptedOutgoingMessage.java

@@ -51,7 +51,7 @@ public class EncryptedOutgoingMessage {
     this.signalingKey    = signalingKey;
   }
 
-  public String serialize() throws IOException {
+  public String serialize() throws CryptoEncodingException {
     byte[]        plaintext  = outgoingMessage.toByteArray();
     SecretKeySpec cipherKey  = getCipherKey (signalingKey);
     SecretKeySpec macKey     = getMacKey(signalingKey);
@@ -61,7 +61,7 @@ public class EncryptedOutgoingMessage {
   }
 
   private byte[] getCiphertext(byte[] plaintext, SecretKeySpec cipherKey, SecretKeySpec macKey)
-      throws IOException
+      throws CryptoEncodingException
   {
     try {
       Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
@@ -85,31 +85,39 @@ public class EncryptedOutgoingMessage {
       throw new AssertionError(e);
     } catch (InvalidKeyException e) {
       logger.warn("Invalid Key", e);
-      throw new IOException("Invalid key!");
+      throw new CryptoEncodingException("Invalid key!");
     }
   }
 
-  private SecretKeySpec getCipherKey(String signalingKey) throws IOException {
-    byte[] signalingKeyBytes = Base64.decode(signalingKey);
-    byte[] cipherKey         = new byte[CIPHER_KEY_SIZE];
+  private SecretKeySpec getCipherKey(String signalingKey) throws CryptoEncodingException {
+    try {
+      byte[] signalingKeyBytes = Base64.decode(signalingKey);
+      byte[] cipherKey         = new byte[CIPHER_KEY_SIZE];
 
-    if (signalingKeyBytes.length < CIPHER_KEY_SIZE)
-      throw new IOException("Signaling key too short!");
+      if (signalingKeyBytes.length < CIPHER_KEY_SIZE)
+        throw new CryptoEncodingException("Signaling key too short!");
 
-    System.arraycopy(signalingKeyBytes, 0, cipherKey, 0, cipherKey.length);
-    return new SecretKeySpec(cipherKey, "AES");
+      System.arraycopy(signalingKeyBytes, 0, cipherKey, 0, cipherKey.length);
+      return new SecretKeySpec(cipherKey, "AES");
+    } catch (IOException e) {
+      throw new CryptoEncodingException(e);
+    }
   }
 
-  private SecretKeySpec getMacKey(String signalingKey) throws IOException {
-    byte[] signalingKeyBytes = Base64.decode(signalingKey);
-    byte[] macKey            = new byte[MAC_KEY_SIZE];
+  private SecretKeySpec getMacKey(String signalingKey) throws CryptoEncodingException {
+    try {
+      byte[] signalingKeyBytes = Base64.decode(signalingKey);
+      byte[] macKey            = new byte[MAC_KEY_SIZE];
 
-    if (signalingKeyBytes.length < CIPHER_KEY_SIZE + MAC_KEY_SIZE)
-      throw new IOException(("Signaling key too short!"));
+      if (signalingKeyBytes.length < CIPHER_KEY_SIZE + MAC_KEY_SIZE)
+        throw new CryptoEncodingException("Signaling key too short!");
 
-    System.arraycopy(signalingKeyBytes, CIPHER_KEY_SIZE, macKey, 0, macKey.length);
+      System.arraycopy(signalingKeyBytes, CIPHER_KEY_SIZE, macKey, 0, macKey.length);
 
-    return new SecretKeySpec(macKey, "HmacSHA256");
+      return new SecretKeySpec(macKey, "HmacSHA256");
+    } catch (IOException e) {
+      throw new CryptoEncodingException(e);
+    }
   }
 
 }

src/main/java/org/whispersystems/textsecuregcm/entities/IncomingMessageList.java

@@ -29,9 +29,20 @@ public class IncomingMessageList {
   @Valid
   private List<IncomingMessage> messages;
 
+  @JsonProperty
+  private String relay;
+
   public IncomingMessageList() {}
 
   public List<IncomingMessage> getMessages() {
     return messages;
   }
+
+  public String getRelay() {
+    return relay;
+  }
+
+  public void setRelay(String relay) {
+    this.relay = relay;
+  }
 }

src/main/java/org/whispersystems/textsecuregcm/entities/MissingDevices.java

@@ -0,0 +1,16 @@
+package org.whispersystems.textsecuregcm.entities;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import java.util.List;
+
+public class MissingDevices {
+
+  @JsonProperty
+  public List<Long> missingDevices;
+
+  public MissingDevices(List<Long> missingDevices) {
+    this.missingDevices = missingDevices;
+  }
+
+}

src/main/java/org/whispersystems/textsecuregcm/entities/PreKey.java

@@ -35,7 +35,6 @@ public class PreKey {
   private String  number;
 
   @JsonProperty
-  @NotNull
   private long deviceId;
 
   @JsonProperty

src/main/java/org/whispersystems/textsecuregcm/entities/UnstructuredPreKeyList.java

@@ -23,14 +23,24 @@ import org.hibernate.validator.constraints.NotEmpty;
 import javax.validation.Valid;
 import javax.validation.constraints.NotNull;
 import java.util.Iterator;
+import java.util.LinkedList;
 import java.util.List;
 
 public class UnstructuredPreKeyList {
+
   @JsonProperty
   @NotNull
   @Valid
   private List<PreKey> keys;
 
+  @VisibleForTesting
+  public UnstructuredPreKeyList() {}
+
+  public UnstructuredPreKeyList(PreKey preKey) {
+    this.keys = new LinkedList<PreKey>();
+    this.keys.add(preKey);
+  }
+
   public UnstructuredPreKeyList(List<PreKey> preKeys) {
     this.keys = preKeys;
   }
@@ -39,7 +49,8 @@ public class UnstructuredPreKeyList {
     return keys;
   }
 
-  @VisibleForTesting public boolean equals(Object o) {
+  @VisibleForTesting
+  public boolean equals(Object o) {
     if (!(o instanceof UnstructuredPreKeyList) ||
         ((UnstructuredPreKeyList) o).keys.size() != keys.size())
       return false;