Addressing Rayo's comments

Author: ankitaj224

firebase-installations-interop/src/main/java/com/google/firebase/installations/InstallationTokenResult.java

@@ -21,12 +21,12 @@
 @AutoValue
 public abstract class InstallationTokenResult {
 
-  /** A new FIS Auth-Token, created for this firebase installation. */
+  /** A new FIS Auth-Token, created for this Firebase Installation. */
   @NonNull
   public abstract String getToken();
   /**
-   * The amount of time, in milliseconds, before the auth-token expires for this firebase
-   * installation.
+   * The amount of time, in milliseconds, before the auth-token expires for this Firebase
+   * Installation.
    */
   @NonNull
   public abstract long getTokenExpirationTimestampMillis();

firebase-installations/src/androidTest/AndroidManifest.xml

@@ -14,7 +14,7 @@
 <!-- limitations under the License. -->
 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.google.firebase.installation">
+    package="com.google.firebase.installations">
 
     <application>
         <uses-library android:name="android.test.runner"/>

firebase-installations/src/androidTest/java/com/google/firebase/installation/FirebaseInstallationInstrumentedTest.java renamed to firebase-installations/src/androidTest/java/com/google/firebase/installations/FirebaseInstallationsInstrumentedTest.java

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.firebase.installation;
+package com.google.firebase.installations;
 
 import androidx.test.runner.AndroidJUnit4;
 import org.junit.FixMethodOrder;
@@ -26,4 +26,4 @@
  */
 @RunWith(AndroidJUnit4.class)
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
-public class FirebaseInstallationInstrumentedTest {}
+public class FirebaseInstallationsInstrumentedTest {}

firebase-installations/src/androidTest/java/com/google/firebase/installation/local/FiidCacheTest.java renamed to firebase-installations/src/androidTest/java/com/google/firebase/installations/local/FiidCacheTest.java

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.firebase.installation.local;
+package com.google.firebase.installations.local;
 
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertNull;
@@ -22,8 +22,6 @@
 import androidx.test.runner.AndroidJUnit4;
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.FirebaseOptions;
-import com.google.firebase.installations.local.FiidCache;
-import com.google.firebase.installations.local.FiidCacheEntryValue;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;

firebase-installations/src/main/java/com/google/firebase/installations/FirebaseInstallationException.java renamed to firebase-installations/src/main/java/com/google/firebase/installations/FirebaseInstallationsException.java

@@ -18,8 +18,9 @@
 import com.google.firebase.FirebaseException;
 
 /** The class for all Exceptions thrown by {@link FirebaseInstallations}. */
-public class FirebaseInstallationException extends FirebaseException {
+public class FirebaseInstallationsException extends FirebaseException {
 
+  // TODO(ankitagj): Improve clear exception handling.
   public enum Status {
     SDK_INTERNAL_ERROR,
 
@@ -28,23 +29,23 @@ public enum Status {
 
   @NonNull private final Status status;
 
-  public FirebaseInstallationException(@NonNull Status status) {
+  public FirebaseInstallationsException(@NonNull Status status) {
     this.status = status;
   }
 
-  public FirebaseInstallationException(@NonNull String message, @NonNull Status status) {
+  public FirebaseInstallationsException(@NonNull String message, @NonNull Status status) {
     super(message);
     this.status = status;
   }
 
-  public FirebaseInstallationException(
+  public FirebaseInstallationsException(
       @NonNull String message, @NonNull Status status, @NonNull Throwable cause) {
     super(message, cause);
     this.status = status;
   }
 
   /**
-   * Gets the status status for the operation that failed.
+   * Gets the status for the operation that failed.
    *
    * @return the status for the FirebaseInstallationsException
    */

firebase-installations/src/main/java/com/google/firebase/installations/Utils.java

@@ -15,6 +15,7 @@
 package com.google.firebase.installations;
 
 import androidx.annotation.NonNull;
+import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.util.UUID;
 
@@ -34,7 +35,7 @@ class Utils {
    */
   public static final byte REMOVE_PREFIX_MASK = Byte.parseByte("00001111", 2);
 
-  /** Length of new-format FIDs. */
+  /** Length of new-format FIDs as introduced in 2019. */
   public static final int FID_LENGTH = 22;
 
   /**
@@ -49,13 +50,8 @@ class Utils {
   @NonNull
   public static String createRandomFid() {
     // A valid FID has exactly 22 base64 characters, which is 132 bits, or 16.5 bytes.
-    // We create 17 random bytes and ignore the last base64 character later.
-    byte[] bytes = UUID.randomUUID().toString().substring(0, 17).getBytes(Charset.defaultCharset());
-
-    // Replace the first 4 random bits with the constant FID header of 0x7 (0b0111).
-    bytes[0] = (byte) (FID_4BIT_PREFIX | (bytes[0] & REMOVE_PREFIX_MASK));
-
-    return encodeFidBase64UrlSafe(bytes);
+    byte[] uuidBytes = getBytesFromUUID(UUID.randomUUID());
+    return encodeFidBase64UrlSafe(uuidBytes);
   }
 
   /**
@@ -78,4 +74,22 @@ private static String encodeFidBase64UrlSafe(byte[] rawValue) {
             Charset.defaultCharset())
         .substring(0, FID_LENGTH);
   }
+
+  private static byte[] getBytesFromUUID(UUID uuid) {
+    ByteBuffer bb = ByteBuffer.wrap(new byte[17]);
+
+    // The first 4 bits with the constant FID header of 0x7 (0b0111) followed by the last 4 random
+    // bits of the UUID.
+    byte fidPrefixWithLast4bitsOfUUID =
+        (byte)
+            (FID_4BIT_PREFIX
+                | (ByteBuffer.allocate(8).putLong(uuid.getLeastSignificantBits()).array()[7]
+                    & REMOVE_PREFIX_MASK));
+
+    bb.put(fidPrefixWithLast4bitsOfUUID);
+    bb.putLong(uuid.getMostSignificantBits());
+    bb.putLong(uuid.getLeastSignificantBits());
+
+    return bb.array();
+  }
 }

firebase-installations/src/main/java/com/google/firebase/installations/remote/FirebaseInstallationServiceClient.java

@@ -50,8 +50,8 @@ public class FirebaseInstallationServiceClient {
 
   @NonNull
   public InstallationResponse createFirebaseInstallation(
-      @NonNull String projectID,
       @NonNull String apiKey,
+      @NonNull String projectID,
       @NonNull String firebaseInstallationId,
       @NonNull String appId)
       throws FirebaseInstallationServiceException {
@@ -115,8 +115,8 @@ private static JSONObject buildCreateFirebaseInstallationRequestBody(String fid,
 
   @NonNull
   public void deleteFirebaseInstallation(
-      @NonNull String projectID,
       @NonNull String apiKey,
+      @NonNull String projectID,
       @NonNull String fid,
       @NonNull String refreshToken)
       throws FirebaseInstallationServiceException {
@@ -159,8 +159,8 @@ public void deleteFirebaseInstallation(
 
   @NonNull
   public InstallationTokenResult generateAuthToken(
-      @NonNull String projectID,
       @NonNull String apiKey,
+      @NonNull String projectID,
       @NonNull String fid,
       @NonNull String refreshToken)
       throws FirebaseInstallationServiceException {