Add findOrCreate helper methods (#6168)

CHANGELOG.md

@@ -7,14 +7,14 @@
 
 ### Enhancements
 
+* [ObjectServer] Added `RealmPermissions.findOrCreate(String roleName)` and `ClassPermissions.findOrCreate(String roleName)` (#6168).
 * `@RealmClass("name")` and `@RealmField("name")` can now be used as a shorthand for defining custom name mappings (#6145).
 * Added support for `RealmQuery.limit(long limit)` (#544).
 
 ### Internal
 
 * Updated to Object Store commit: 7e19c51af72c3343b453b8a13c82dfda148e4bbc
 
-
 ## 5.5.1 (YYYY-MM-DD)
 
 ### Enhancements

realm/realm-library/src/androidTestObjectServer/java/io/realm/ObjectLevelPermissionsTest.java

@@ -520,6 +520,118 @@ public void allPrivileges() {
         assertNoAccess(nobody);
     }
 
+    @Test
+    public void findOrCreate_unmanagedObjectThrows() {
+        RealmPermissions realmPermissions = new RealmPermissions();
+        try {
+            realmPermissions.findOrCreate("foo");
+            fail();
+        } catch (IllegalStateException ignored) {
+        }
+
+        ClassPermissions classPermissions = new ClassPermissions();
+        try {
+            classPermissions.findOrCreate("foo");
+            fail();
+        } catch (IllegalStateException ignored) {
+        }
+    }
+
+    @Test
+    public void findOrCreate_notInTransactionThrows() {
+        RealmPermissions realmPermissions = realm.getPermissions();
+        try {
+            realmPermissions.findOrCreate("foo");
+            fail();
+        } catch (IllegalStateException ignored) {
+        }
+
+        ClassPermissions classPermissions = realm.getPermissions(ClassPermissions.class);
+        try {
+            classPermissions.findOrCreate("foo");
+            fail();
+        } catch (IllegalStateException ignored) {
+        }
+    }
+
+    @Test
+    public void findOrCreate_nullThrows() {
+        realm.beginTransaction();
+        RealmPermissions realmPermissions = realm.getPermissions();
+        try {
+            //noinspection ConstantConditions
+            realmPermissions.findOrCreate(null);
+            fail();
+        } catch (IllegalArgumentException ignored) {
+        }
+
+        ClassPermissions classPermissions = realm.getPermissions(ClassPermissions.class);
+        try {
+            //noinspection ConstantConditions
+            classPermissions.findOrCreate(null);
+            fail();
+        } catch (IllegalArgumentException ignored) {
+        }
+    }
+
+    @Test
+    public void findOrCreate_createRole() {
+        realm.beginTransaction();
+        assertNull(realm.where(Role.class).equalTo("name", "role1").findFirst());
+        assertNull(realm.where(Role.class).equalTo("name", "role2").findFirst());
+
+        // Realm permissions
+        RealmPermissions realmPermissions = realm.getPermissions();
+        Permission p = realmPermissions.findOrCreate("role1");
+        assertEquals("role1", p.getRole().getName());
+        assertTrue(p.getRole().getMembers().isEmpty());
+
+        // Class permissions
+        ClassPermissions classPermissions = realm.getPermissions(ClassPermissions.class);
+        p = classPermissions.findOrCreate("role2");
+        assertEquals("role2", p.getRole().getName());
+        assertTrue(p.getRole().getMembers().isEmpty());
+    }
+
+    @Test
+    public void findOrCreate_createPermission() {
+        realm.beginTransaction();
+        realm.createObject(Role.class, "role1");
+
+        RealmPermissions realmPermissions = realm.getPermissions();
+        assertEquals(1, realmPermissions.getPermissions().size());
+        Permission p = realmPermissions.findOrCreate("role1");
+        assertNoAccess(p);
+        assertEquals("role1", p.getRole().getName());
+        assertEquals(2, realmPermissions.getPermissions().size());
+        assertTrue(p.equals(realmPermissions.getPermissions().last()));
+
+        // Class permissions
+        ClassPermissions classPermissions = realm.getPermissions(ClassPermissions.class);
+        assertEquals(1, classPermissions.getPermissions().size());
+        p = classPermissions.findOrCreate("role2");
+        assertNoAccess(p);
+        assertEquals("role2", p.getRole().getName());
+        assertEquals(2, classPermissions.getPermissions().size());
+        assertTrue(p.equals(classPermissions.getPermissions().last()));
+    }
+
+    @Test
+    public void findOrCreate_findExistingPermission() {
+        realm.beginTransaction();
+
+        RealmPermissions realmPermissions = realm.getPermissions();
+        Permission p = realmPermissions.findOrCreate("everyone");
+        assertFullAccess(p);
+        assertEquals("everyone", p.getRole().getName());
+
+        ClassPermissions classPermissions = realm.getPermissions(ClassPermissions.class);
+        p = classPermissions.findOrCreate("everyone");
+        assertFullAccess(p);
+        assertEquals("everyone", p.getRole().getName());
+    }
+
+
     private void assertFullAccess(RealmPrivileges privileges) {
         assertTrue(privileges.canRead());
         assertTrue(privileges.canUpdate());

realm/realm-library/src/main/java/io/realm/internal/sync/PermissionHelper.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2018 Realm Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.realm.internal.sync;
+
+import io.realm.Realm;
+import io.realm.RealmList;
+import io.realm.RealmObject;
+import io.realm.internal.annotations.ObjectServer;
+import io.realm.sync.permissions.Permission;
+import io.realm.sync.permissions.Role;
+
+/**
+ * Helper class for working with fine-grained permissions
+ */
+@ObjectServer
+public class PermissionHelper {
+
+    /**
+     * Finds or creates the permission object for a given role. Creating objects if they cannot
+     * be found.
+     *
+     * @param container RealmObject containg the permission objects
+     * @param permissions the list of permissions
+     * @param roleName the role to search for
+     * @return
+     */
+    public static Permission findOrCreatePermissionForRole(RealmObject container, RealmList<Permission> permissions, String roleName) {
+        if (!container.isManaged()) {
+            throw new IllegalStateException("'findOrCreate()' can only be called on managed objects.");
+        }
+        Realm realm = container.getRealm();
+        if (!realm.isInTransaction()) {
+            throw new IllegalStateException("'findOrCreate()' can only be called inside a write transaction.");
+        }
+
+        // Find existing permission object or create new one
+        Permission permission = permissions.where().equalTo("role.name", roleName).findFirst();
+        if (permission == null) {
+
+            // Find existing role or create new one
+            Role role = realm.where(Role.class).equalTo("name", roleName).findFirst();
+            if (role == null) {
+                role = realm.createObject(Role.class, roleName);
+            }
+
+            permission = realm.copyToRealm(new Permission.Builder(role).noPrivileges().build());
+            permissions.add(permission);
+        }
+
+        return permission;
+    }
+}

realm/realm-library/src/main/java/io/realm/sync/permissions/ClassPermissions.java

@@ -23,6 +23,7 @@
 import io.realm.annotations.RealmClass;
 import io.realm.annotations.Required;
 import io.realm.internal.annotations.ObjectServer;
+import io.realm.internal.sync.PermissionHelper;
 
 /**
  * Class describing all permissions related to a given Realm model class. These permissions will
@@ -61,6 +62,7 @@ public ClassPermissions() {
      * @param clazz class to create permissions.
      */
     public ClassPermissions(Class<? extends RealmModel> clazz) {
+        //noinspection ConstantConditions
         if (clazz == null) {
             throw new IllegalArgumentException("Non-null 'clazz' required.");
         }
@@ -89,4 +91,26 @@ public String getName() {
     public RealmList<Permission> getPermissions() {
         return permissions;
     }
+
+    /**
+     * Finds the permissions associated with a given {@link Role}. If either the role or the permission
+     * object doesn't exists, it will be created.
+     * <p>
+     * If the {@link Permission} object is created because one didn't exist already, it will be
+     * created with all privileges disabled.
+     * <p>
+     * If the the {@link Role} object is created because one didn't exists, it will be created
+     * with no members.
+     *
+     * @param roleName name of the role to find.
+     * @return permission object for the given role.
+     * @throws IllegalStateException if this object is not managed by Realm.
+     * @throws IllegalStateException if this method is not called inside a write transaction.
+     * @throws IllegalArgumentException if a {@code null} or empty
+     */
+    public Permission findOrCreate(String roleName) {
+        // Error handling done in the helper class
+        return PermissionHelper.findOrCreatePermissionForRole(this, permissions, roleName);
+    }
+
 }

realm/realm-library/src/main/java/io/realm/sync/permissions/RealmPermissions.java

@@ -15,11 +15,13 @@
  */
 package io.realm.sync.permissions;
 
+import io.realm.Realm;
 import io.realm.RealmList;
 import io.realm.RealmObject;
 import io.realm.annotations.PrimaryKey;
 import io.realm.annotations.RealmClass;
 import io.realm.internal.annotations.ObjectServer;
+import io.realm.internal.sync.PermissionHelper;
 
 /**
  * Class describing all permissions related to a given Realm. Permissions attached to this class
@@ -48,4 +50,25 @@ public RealmPermissions() {
     public RealmList<Permission> getPermissions() {
         return permissions;
     }
+
+    /**
+     * Finds the permissions associated with a given {@link Role}. If either the role or the permission
+     * object doesn't exists, it will be created.
+     * <p>
+     * If the {@link Permission} object is created because one didn't exist already, it will be
+     * created with all privileges disabled.
+     * <p>
+     * If the role {@link Role} object is created because one didn't exists, it will be created
+     * with no members.
+     *
+     * @param roleName name of the role to find.
+     * @return permission object for the given role.
+     * @throws IllegalStateException if this object is not managed by Realm.
+     * @throws IllegalStateException if this method is not called inside a write transaction.
+     * @throws IllegalArgumentException if a {@code null} or empty
+     */
+    public Permission findOrCreate(String roleName) {
+        // Error handling done in the helper class
+        return PermissionHelper.findOrCreatePermissionForRole(this, permissions, roleName);
+    }
 }