[DeviceConfig] add an API to delete a property

Currently there is only a shell command to delete a property.
Adding an API to do the same.

BUG: 184001163
Test: atest android.provider.DeviceConfigTest
Test: atest CtsDeviceConfigTestCases
Test: atest com.android.server.testables.TestableDeviceConfigTest
Change-Id: I43d7177c509501efd65e32ab3ad000d17d6ffb6c

core/api/system-current.txt

@@ -9079,6 +9079,7 @@ package android.provider {
 
   public final class DeviceConfig {
     method @RequiresPermission(android.Manifest.permission.READ_DEVICE_CONFIG) public static void addOnPropertiesChangedListener(@NonNull String, @NonNull java.util.concurrent.Executor, @NonNull android.provider.DeviceConfig.OnPropertiesChangedListener);
+    method @RequiresPermission(android.Manifest.permission.WRITE_DEVICE_CONFIG) public static boolean deleteProperty(@NonNull String, @NonNull String);
     method @RequiresPermission(android.Manifest.permission.READ_DEVICE_CONFIG) public static boolean getBoolean(@NonNull String, @NonNull String, boolean);
     method @RequiresPermission(android.Manifest.permission.READ_DEVICE_CONFIG) public static float getFloat(@NonNull String, @NonNull String, float);
     method @RequiresPermission(android.Manifest.permission.READ_DEVICE_CONFIG) public static int getInt(@NonNull String, @NonNull String, int);

core/java/android/provider/DeviceConfig.java

@@ -794,7 +794,7 @@ public final class DeviceConfig {
     }
 
     /**
-     * Create a new property with the the provided name and value in the provided namespace, or
+     * Create a new property with the provided name and value in the provided namespace, or
      * update the value of such a property if it already exists. The same name can exist in multiple
      * namespaces and might have different values in any or all namespaces.
      * <p>
@@ -843,6 +843,22 @@ public final class DeviceConfig {
                 properties.mMap);
     }
 
+    /**
+     * Delete a property with the provided name and value in the provided namespace
+     *
+     * @param namespace   The namespace containing the property to create or update.
+     * @param name        The name of the property to create or update.
+     * @return True if the property was deleted or it did not exist in the first place.
+     * False if the storage implementation throws errors.
+     * @hide
+     */
+    @SystemApi
+    @RequiresPermission(WRITE_DEVICE_CONFIG)
+    public static boolean deleteProperty(@NonNull String namespace, @NonNull String name) {
+        ContentResolver contentResolver = ActivityThread.currentApplication().getContentResolver();
+        return Settings.Config.deleteString(contentResolver, namespace, name);
+    }
+
     /**
      * Reset properties to their default values by removing the underlying values.
      * <p>

core/java/android/provider/Settings.java

@@ -2770,6 +2770,7 @@ public final class Settings {
         // for the fast path of retrieving settings.
         private final String mCallGetCommand;
         private final String mCallSetCommand;
+        private final String mCallDeleteCommand;
         private final String mCallListCommand;
         private final String mCallSetAllCommand;
 
@@ -2781,17 +2782,19 @@ public final class Settings {
         private GenerationTracker mGenerationTracker;
 
         <T extends NameValueTable> NameValueCache(Uri uri, String getCommand,
-                String setCommand, ContentProviderHolder providerHolder, Class<T> callerClass) {
+                String setCommand, String deleteCommand, ContentProviderHolder providerHolder,
-            this(uri, getCommand, setCommand, null, null, providerHolder,
+                Class<T> callerClass) {
+            this(uri, getCommand, setCommand, deleteCommand, null, null, providerHolder,
                     callerClass);
         }
 
         private <T extends NameValueTable> NameValueCache(Uri uri, String getCommand,
-                String setCommand, String listCommand, String setAllCommand,
+                String setCommand, String deleteCommand, String listCommand, String setAllCommand,
                 ContentProviderHolder providerHolder, Class<T> callerClass) {
             mUri = uri;
             mCallGetCommand = getCommand;
             mCallSetCommand = setCommand;
+            mCallDeleteCommand = deleteCommand;
             mCallListCommand = listCommand;
             mCallSetAllCommand = setAllCommand;
             mProviderHolder = providerHolder;
@@ -2849,6 +2852,20 @@ public final class Settings {
             }
         }
 
+        public boolean deleteStringForUser(ContentResolver cr, String name, final int userHandle) {
+            try {
+                Bundle arg = new Bundle();
+                arg.putInt(CALL_METHOD_USER_KEY, userHandle);
+                IContentProvider cp = mProviderHolder.getProvider(cr);
+                cp.call(cr.getAttributionSource(),
+                        mProviderHolder.mUri.getAuthority(), mCallDeleteCommand, name, arg);
+            } catch (RemoteException e) {
+                Log.w(TAG, "Can't delete key " + name + " in " + mUri, e);
+                return false;
+            }
+            return true;
+        }
+
         @UnsupportedAppUsage
         public String getStringForUser(ContentResolver cr, String name, final int userHandle) {
             // Check if the target settings key is readable. Reject if the caller is not system and
@@ -3311,6 +3328,7 @@ public final class Settings {
                 CONTENT_URI,
                 CALL_METHOD_GET_SYSTEM,
                 CALL_METHOD_PUT_SYSTEM,
+                CALL_METHOD_DELETE_SYSTEM,
                 sProviderHolder,
                 System.class);
 
@@ -5631,6 +5649,7 @@ public final class Settings {
                 CONTENT_URI,
                 CALL_METHOD_GET_SECURE,
                 CALL_METHOD_PUT_SECURE,
+                CALL_METHOD_DELETE_SECURE,
                 sProviderHolder,
                 Secure.class);
 
@@ -15022,6 +15041,7 @@ public final class Settings {
                     CONTENT_URI,
                     CALL_METHOD_GET_GLOBAL,
                     CALL_METHOD_PUT_GLOBAL,
+                    CALL_METHOD_DELETE_GLOBAL,
                     sProviderHolder,
                     Global.class);
 
@@ -16564,6 +16584,7 @@ public final class Settings {
                 DeviceConfig.CONTENT_URI,
                 CALL_METHOD_GET_CONFIG,
                 CALL_METHOD_PUT_CONFIG,
+                CALL_METHOD_DELETE_CONFIG,
                 CALL_METHOD_LIST_CONFIG,
                 CALL_METHOD_SET_ALL_CONFIG,
                 sProviderHolder,
@@ -16672,6 +16693,26 @@ public final class Settings {
             throw new DeviceConfig.BadConfigException();
         }
 
+        /**
+         * Delete a name/value pair from the database for the specified namespace.
+         *
+         * @param resolver to access the database with.
+         * @param namespace to delete the name/value pair from.
+         * @param name to delete.
+         * @return true if the value was deleted, false on database errors. If the name/value pair
+         * did not exist, return True.
+         *
+         * @see #resetToDefaults(ContentResolver, int, String)
+         *
+         * @hide
+         */
+        @RequiresPermission(Manifest.permission.WRITE_DEVICE_CONFIG)
+        static boolean deleteString(@NonNull ContentResolver resolver, @NonNull String namespace,
+                @NonNull String name) {
+            return sNameValueCache.deleteStringForUser(resolver,
+                    createCompositeName(namespace, name), resolver.getUserId());
+        }
+
         /**
          * Reset the values to their defaults.
          * <p>

core/tests/coretests/src/android/provider/DeviceConfigTest.java

@@ -832,4 +832,80 @@ public class DeviceConfigTest {
         return compositeName.equals(result.getString(Settings.NameValueTable.VALUE));
     }
 
+    @Test
+    public void deleteProperty_nullNamespace() {
+        try {
+            DeviceConfig.deleteProperty(null, KEY);
+            Assert.fail("Null namespace should have resulted in an NPE.");
+        } catch (NullPointerException e) {
+            // expected
+        }
+    }
+
+    @Test
+    public void deleteProperty_nullName() {
+        try {
+            DeviceConfig.deleteProperty(NAMESPACE, null);
+            Assert.fail("Null name should have resulted in an NPE.");
+        } catch (NullPointerException e) {
+            // expected
+        }
+    }
+
+    @Test
+    public void deletePropertyString() {
+        final String value = "new_value";
+        final String default_value = "default";
+        DeviceConfig.setProperty(NAMESPACE, KEY, value, false);
+        DeviceConfig.deleteProperty(NAMESPACE, KEY);
+        final String result = DeviceConfig.getString(NAMESPACE, KEY, default_value);
+        assertThat(result).isEqualTo(default_value);
+    }
+
+    @Test
+    public void deletePropertyBoolean() {
+        final boolean value = true;
+        final boolean default_value = false;
+        DeviceConfig.setProperty(NAMESPACE, KEY, String.valueOf(value), false);
+        DeviceConfig.deleteProperty(NAMESPACE, KEY);
+        final boolean result = DeviceConfig.getBoolean(NAMESPACE, KEY, default_value);
+        assertThat(result).isEqualTo(default_value);
+    }
+
+    @Test
+    public void deletePropertyInt() {
+        final int value = 123;
+        final int default_value = 999;
+        DeviceConfig.setProperty(NAMESPACE, KEY, String.valueOf(value), false);
+        DeviceConfig.deleteProperty(NAMESPACE, KEY);
+        final int result = DeviceConfig.getInt(NAMESPACE, KEY, default_value);
+        assertThat(result).isEqualTo(default_value);
+    }
+
+    @Test
+    public void deletePropertyLong() {
+        final long value = 456789;
+        final long default_value = 123456;
+        DeviceConfig.setProperty(NAMESPACE, KEY, String.valueOf(value), false);
+        DeviceConfig.deleteProperty(NAMESPACE, KEY);
+        final long result = DeviceConfig.getLong(NAMESPACE, KEY, default_value);
+        assertThat(result).isEqualTo(default_value);
+    }
+
+    @Test
+    public void deletePropertyFloat() {
+        final float value = 456.789f;
+        final float default_value = 123.456f;
+        DeviceConfig.setProperty(NAMESPACE, KEY, String.valueOf(value), false);
+        DeviceConfig.deleteProperty(NAMESPACE, KEY);
+        final float result = DeviceConfig.getFloat(NAMESPACE, KEY, default_value);
+        assertThat(result).isEqualTo(default_value);
+    }
+
+    @Test
+    public void deleteProperty_empty() {
+        assertThat(DeviceConfig.deleteProperty(NAMESPACE, KEY)).isTrue();
+        final String result = DeviceConfig.getString(NAMESPACE, KEY, null);
+        assertThat(result).isNull();
+    }
 }

services/tests/mockingservicestests/src/com/android/server/testables/TestableDeviceConfig.java

@@ -100,6 +100,15 @@ public final class TestableDeviceConfig implements StaticMockFixture {
                 }
         ).when(() -> DeviceConfig.setProperty(anyString(), anyString(), anyString(), anyBoolean()));
 
+        doAnswer((Answer<Boolean>) invocationOnMock -> {
+                    String namespace = invocationOnMock.getArgument(0);
+                    String name = invocationOnMock.getArgument(1);
+                    mKeyValueMap.remove(getKey(namespace, name));
+                    invokeListeners(namespace, getProperties(namespace, name, null));
+                    return true;
+                }
+        ).when(() -> DeviceConfig.deleteProperty(anyString(), anyString()));
+
         doAnswer((Answer<Boolean>) invocationOnMock -> {
                     Properties properties = invocationOnMock.getArgument(0);
                     String namespace = properties.getNamespace();

services/tests/mockingservicestests/src/com/android/server/testables/TestableDeviceConfigTest.java

@@ -102,6 +102,20 @@ public class TestableDeviceConfigTest {
         assertThat(DeviceConfig.getProperty(sNamespace, newKey)).isEqualTo(newValue);
     }
 
+    @Test
+    public void deleteProperty() {
+        DeviceConfig.setProperty(sNamespace, sKey, sValue, false);
+        assertThat(DeviceConfig.getProperty(sNamespace, sKey)).isEqualTo(sValue);
+        DeviceConfig.deleteProperty(sNamespace, sKey);
+        assertThat(DeviceConfig.getProperty(sNamespace, sKey)).isNull();
+        String newNamespace = "namespace2";
+        String newValue = "value2";
+        DeviceConfig.setProperty(newNamespace, sKey, newValue, false);
+        assertThat(DeviceConfig.getProperty(newNamespace, sKey)).isEqualTo(newValue);
+        DeviceConfig.deleteProperty(newNamespace, sKey);
+        assertThat(DeviceConfig.getProperty(newNamespace, sKey)).isNull();
+    }
+
     @Test
     public void getProperties_empty() {
         String newKey = "key2";
@@ -189,6 +203,27 @@ public class TestableDeviceConfigTest {
         }
     }
 
+    @Test
+    public void testListener_deleteProperty() throws InterruptedException {
+        CountDownLatch countDownLatch = new CountDownLatch(1);
+
+        OnPropertiesChangedListener changeListener = (properties) -> {
+            assertThat(properties.getNamespace()).isEqualTo(sNamespace);
+            assertThat(properties.getKeyset()).containsExactly(sKey);
+            assertThat(properties.getString(sKey, "bogus_value")).isEqualTo("bogus_value");
+            assertThat(properties.getString("bogus_key", "bogus_value")).isEqualTo("bogus_value");
+            countDownLatch.countDown();
+        };
+        try {
+            DeviceConfig.addOnPropertiesChangedListener(sNamespace,
+                    ActivityThread.currentApplication().getMainExecutor(), changeListener);
+            DeviceConfig.deleteProperty(sNamespace, sKey);
+            assertThat(countDownLatch.await(
+                    WAIT_FOR_PROPERTY_CHANGE_TIMEOUT_MILLIS, TimeUnit.MILLISECONDS)).isTrue();
+        } finally {
+            DeviceConfig.removeOnPropertiesChangedListener(changeListener);
+        }
+    }
 }