Implement controller to disable transcoding cache

This is to provide users with control over whether to disable
transcoding cache or not.

By default we keep the transcoding cache enabled.

The controller resides within the Media transcoding settings under
Developer Options.

Test: Manual. Unit tests added.
Bug: 185246580
Change-Id: I5cc85e4a254c87b5c84c32a303e8294c918748c2

res/xml/transcode_settings.xml

@@ -40,4 +40,9 @@
         android:key="transcode_notification"
         android:title="@string/transcode_notification"
         settings:controller="com.android.settings.development.transcode.TranscodeNotificationPreferenceController" />
+
+    <SwitchPreference
+        android:key="transcode_disable_cache"
+        android:title="@string/transcode_disable_cache"
+        settings:controller="com.android.settings.development.transcode.TranscodeDisableCachePreferenceController" />
 </PreferenceScreen>

src/com/android/settings/development/transcode/TranscodeDisableCachePreferenceController.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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 com.android.settings.development.transcode;
+
+import android.content.Context;
+import android.os.SystemProperties;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.settings.core.TogglePreferenceController;
+
+/**
+ * The controller (in the Media transcoding settings) indicating the user's preference to disable
+ * the cache for transcoding.
+ */
+public class TranscodeDisableCachePreferenceController extends TogglePreferenceController {
+    @VisibleForTesting
+    static final String TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY =
+            "persist.sys.fuse.disable_transcode_cache";
+
+    public TranscodeDisableCachePreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+    }
+
+    @Override
+    public boolean isChecked() {
+        return SystemProperties.getBoolean(TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY, false);
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        SystemProperties.set(TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY, String.valueOf(isChecked));
+        return true;
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+}

tests/unit/src/com/android/settings/development/transcode/TranscodeDefaultOptionPreferenceControllerTest.java

@@ -70,7 +70,7 @@ public class TranscodeDefaultOptionPreferenceControllerTest {
     }
 
     @Test
-    public void getAvailabilityStatus_shouldReturn_isAvailable() {
+    public void getAvailabilityStatus_shouldReturnAVAILABLE() {
         assertThat(mUnderTest.getAvailabilityStatus()).isEqualTo(
                 BasePreferenceController.AVAILABLE);
     }

tests/unit/src/com/android/settings/development/transcode/TranscodeDisableCachePreferenceControllerTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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 com.android.settings.development.transcode;
+
+import static com.android.settings.development.transcode.TranscodeDisableCachePreferenceController.TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.os.SystemProperties;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import com.android.settings.core.BasePreferenceController;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class TranscodeDisableCachePreferenceControllerTest {
+
+    private TranscodeUserControlPreferenceController mUnderTest;
+
+    @Before
+    public void setUp() {
+        Context context = ApplicationProvider.getApplicationContext();
+        mUnderTest = new TranscodeUserControlPreferenceController(context, "some_key");
+    }
+
+    @Test
+    public void isChecked_whenSysPropSet_shouldReturnTrue() {
+        SystemProperties.set(TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY, "true");
+        assertThat(mUnderTest.isChecked()).isTrue();
+    }
+
+    @Test
+    public void isChecked_whenSysPropUnset_shouldReturnFalse() {
+        SystemProperties.set(TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY, "false");
+        assertThat(mUnderTest.isChecked()).isFalse();
+    }
+
+    @Test
+    public void setChecked_withTrue_shouldSetSysProp() {
+        mUnderTest.setChecked(true);
+        assertThat(
+                SystemProperties.getBoolean(TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY, false)).isTrue();
+    }
+
+    @Test
+    public void setChecked_withFalse_shouldUnsetSysProp() {
+        mUnderTest.setChecked(false);
+        assertThat(
+                SystemProperties.getBoolean(TRANSCODE_DISABLE_CACHE_SYS_PROP_KEY, true)).isFalse();
+    }
+
+    @Test
+    public void getAvailabilityStatus_shouldReturnAVAILABLE() {
+        assertThat(mUnderTest.getAvailabilityStatus()).isEqualTo(
+                BasePreferenceController.AVAILABLE);
+    }
+}

tests/unit/src/com/android/settings/development/transcode/TranscodeNotificationPreferenceControllerTest.java

@@ -69,7 +69,7 @@ public class TranscodeNotificationPreferenceControllerTest {
     }
 
     @Test
-    public void getAvailabilityStatus_shouldReturn_isAvailable() {
+    public void getAvailabilityStatus_shouldReturnAVAILABLE() {
         assertThat(mUnderTest.getAvailabilityStatus()).isEqualTo(
                 BasePreferenceController.AVAILABLE);
     }

tests/unit/src/com/android/settings/development/transcode/TranscodeUserControlPreferenceControllerTest.java

@@ -70,7 +70,7 @@ public class TranscodeUserControlPreferenceControllerTest {
     }
 
     @Test
-    public void getAvailabilityStatus_shouldReturn_isAvailable() {
+    public void getAvailabilityStatus_shouldReturnAVAILABLE() {
         assertThat(mUnderTest.getAvailabilityStatus()).isEqualTo(
                 BasePreferenceController.AVAILABLE);
     }