Read font attributes from buffer.

minikin::Font::typeface() is expensive because it will open the font file.
Font attribute getters should avoid calling it.

Bug: 188201287
Test: atest UpdatableSystemFontTest
Test: atest CtsGraphicsTestCases:FontTest
Test: atest CtsGraphicsTestCases:SystemFontsTest
Change-Id: Ic8554f6dfacbe27ddfea6b375633c96bced2cc09

tests/UpdatableSystemFontTest/Android.bp

@@ -27,6 +27,7 @@ android_test {
     libs: ["android.test.runner"],
     static_libs: [
         "androidx.test.ext.junit",
+        "androidx.test.uiautomator_uiautomator",
         "compatibility-device-util-axt",
         "platform-test-annotations",
         "truth-prebuilt",

tests/UpdatableSystemFontTest/EmojiRenderingTestApp/AndroidManifest.xml

@@ -19,5 +19,6 @@
     package="com.android.emojirenderingtestapp">
     <application>
         <activity android:name=".EmojiRenderingTestActivity"/>
+        <activity android:name=".GetAvailableFontsTestActivity"/>
     </application>
 </manifest>

tests/UpdatableSystemFontTest/EmojiRenderingTestApp/src/com/android/emojirenderingtestapp/GetAvailableFontsTestActivity.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.emojirenderingtestapp;
+
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
+
+import android.app.Activity;
+import android.graphics.fonts.Font;
+import android.graphics.fonts.SystemFonts;
+import android.os.Bundle;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+public class GetAvailableFontsTestActivity extends Activity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        String emojiFontPath = "<Not found>";
+        for (Font font : SystemFonts.getAvailableFonts()) {
+            // Calls font attribute getters to make sure that they don't open font files.
+            font.getAxes();
+            font.getFile();
+            font.getLocaleList();
+            font.getStyle();
+            font.getTtcIndex();
+            if ("NotoColorEmoji.ttf".equals(font.getFile().getName())) {
+                emojiFontPath = font.getFile().getAbsolutePath();
+            }
+        }
+        LinearLayout container = new LinearLayout(this);
+        container.setOrientation(LinearLayout.VERTICAL);
+        TextView textView = new TextView(this);
+        textView.setText(emojiFontPath);
+        container.addView(textView, new LinearLayout.LayoutParams(MATCH_PARENT, WRAP_CONTENT));
+        setContentView(container);
+    }
+}

tests/UpdatableSystemFontTest/src/com/android/updatablesystemfont/UpdatableSystemFontTest.java

@@ -40,6 +40,9 @@ import android.util.Pair;
 import androidx.annotation.Nullable;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.uiautomator.By;
+import androidx.test.uiautomator.UiDevice;
+import androidx.test.uiautomator.Until;
 
 import com.android.compatibility.common.util.StreamUtil;
 import com.android.compatibility.common.util.SystemUtil;
@@ -101,6 +104,9 @@ public class UpdatableSystemFontTest {
             EMOJI_RENDERING_TEST_APP_ID + "/.EmojiRenderingTestActivity";
     private static final long ACTIVITY_TIMEOUT_MILLIS = SECONDS.toMillis(10);
 
+    private static final String GET_AVAILABLE_FONTS_TEST_ACTIVITY =
+            EMOJI_RENDERING_TEST_APP_ID + "/.GetAvailableFontsTestActivity";
+
     private static final Pattern PATTERN_FONT_FILES = Pattern.compile("\\.(ttf|otf|ttc|otc)$");
     private static final Pattern PATTERN_TMP_FILES = Pattern.compile("^/data/local/tmp/");
     private static final Pattern PATTERN_DATA_FONT_FILES = Pattern.compile("^/data/fonts/files/");
@@ -109,6 +115,7 @@ public class UpdatableSystemFontTest {
 
     private String mKeyId;
     private FontManager mFontManager;
+    private UiDevice mUiDevice;
 
     @Before
     public void setUp() throws Exception {
@@ -120,6 +127,7 @@ public class UpdatableSystemFontTest {
         mKeyId = insertCert(CERT_PATH);
         mFontManager = context.getSystemService(FontManager.class);
         expectCommandToSucceed("cmd font clear");
+        mUiDevice = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation());
     }
 
     @After
@@ -287,6 +295,19 @@ public class UpdatableSystemFontTest {
         assertThat(countMatch(openFiles, patternEmojiVPlus1)).isEqualTo(0);
     }
 
+    @Test
+    public void getAvailableFonts() throws Exception {
+        String fontPath = getFontPath(NOTO_COLOR_EMOJI_POSTSCRIPT_NAME);
+        startActivity(EMOJI_RENDERING_TEST_APP_ID, GET_AVAILABLE_FONTS_TEST_ACTIVITY);
+        // GET_AVAILABLE_FONTS_TEST_ACTIVITY shows the NotoColorEmoji path it got.
+        mUiDevice.wait(
+                Until.findObject(By.pkg(EMOJI_RENDERING_TEST_APP_ID).text(fontPath)),
+                ACTIVITY_TIMEOUT_MILLIS);
+        // The font file should not be opened just by querying the path using
+        // SystemFont.getAvailableFonts().
+        assertThat(isFileOpenedBy(fontPath, EMOJI_RENDERING_TEST_APP_ID)).isFalse();
+    }
+
     private static String insertCert(String certPath) throws Exception {
         Pair<String, String> result;
         try (InputStream is = new FileInputStream(certPath)) {