Add cache for PackageManager.getPackageUid to improvement performance

Context: `PackageManager.getPackageUid` is IPC which could be slow. Add a map in BatteryDiffEntry to cache the data. The cache lifecycle would be the same as other cache in BatteryDiffEntry.

Test: manual
Bug: 304439237
Fix: 304439237
Change-Id: I98d9c8cfee24dd43e9a4037b1b61c8353bf1bcea

src/com/android/settings/fuelgauge/batteryusage/BatteryDiffEntry.java

@@ -45,6 +45,9 @@ public class BatteryDiffEntry {
     // Caches app label and icon to improve loading performance.
     static final Map<String, BatteryEntry.NameAndIcon> sResourceCache = new HashMap<>();
 
+    // Caches package name and uid to improve loading performance.
+    static final Map<String, Integer> sPackageNameAndUidCache = new HashMap<>();
+
     // Whether a specific item is valid to launch restriction page?
     @VisibleForTesting(otherwise = VisibleForTesting.PACKAGE_PRIVATE)
     static final Map<String, Boolean> sValidForRestriction = new HashMap<>();
@@ -289,10 +292,20 @@ public class BatteryDiffEntry {
             return false;
         }
 
-        final int uid = BatteryUtils.getInstance(mContext).getPackageUid(packageName);
+        final int uid = getPackageUid(packageName);
         return uid == BatteryUtils.UID_REMOVED_APPS || uid == BatteryUtils.UID_NULL;
     }
 
+    private int getPackageUid(String packageName) {
+        if (sPackageNameAndUidCache.containsKey(packageName)) {
+            return sPackageNameAndUidCache.get(packageName);
+        }
+
+        int uid = BatteryUtils.getInstance(mContext).getPackageUid(packageName);
+        sPackageNameAndUidCache.put(packageName, uid);
+        return uid;
+    }
+
     void loadLabelAndIcon() {
         if (mIsLoaded) {
             return;
@@ -498,10 +511,11 @@ public class BatteryDiffEntry {
         return builder.toString();
     }
 
-    /** Clears app icon and label cache data. */
+    /** Clears all cache data. */
     public static void clearCache() {
         sResourceCache.clear();
         sValidForRestriction.clear();
+        sPackageNameAndUidCache.clear();
     }
 
     private Drawable getBadgeIconForUser(Drawable icon) {

tests/robotests/src/com/android/settings/fuelgauge/batteryusage/BatteryDiffEntryTest.java

@@ -352,16 +352,18 @@ public final class BatteryDiffEntryTest {
     }
 
     @Test
-    public void testClearCache_clearDataForResourcesAndFlags() {
+    public void testClearCache_clearDataForAllCaches() {
         BatteryDiffEntry.sResourceCache.put(
                 "fake application key",
                 new BatteryEntry.NameAndIcon("app label", null, /* iconId= */ 0));
         BatteryDiffEntry.sValidForRestriction.put("fake application key", Boolean.valueOf(false));
+        BatteryDiffEntry.sPackageNameAndUidCache.put(PACKAGE_NAME, UID);
 
         BatteryDiffEntry.clearCache();
 
         assertThat(BatteryDiffEntry.sResourceCache).isEmpty();
         assertThat(BatteryDiffEntry.sValidForRestriction).isEmpty();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache).isEmpty();
     }
 
     @Test
@@ -445,7 +447,11 @@ public final class BatteryDiffEntryTest {
         final BatteryDiffEntry entry = createBatteryDiffEntry(10, new BatteryHistEntry(values));
 
         assertThat(entry.isSystemEntry()).isFalse();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.containsKey(PACKAGE_NAME)).isFalse();
         assertThat(entry.isUninstalledEntry()).isFalse();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.containsKey(PACKAGE_NAME)).isTrue();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.get(PACKAGE_NAME)).isEqualTo(UID);
+
     }
 
     @Test
@@ -457,7 +463,9 @@ public final class BatteryDiffEntryTest {
         final BatteryDiffEntry entry = createBatteryDiffEntry(10, new BatteryHistEntry(values));
 
         assertThat(entry.isSystemEntry()).isFalse();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.containsKey(PACKAGE_NAME)).isFalse();
         assertThat(entry.isUninstalledEntry()).isFalse();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.containsKey(PACKAGE_NAME)).isFalse();
     }
 
     @Test
@@ -469,7 +477,11 @@ public final class BatteryDiffEntryTest {
         final BatteryDiffEntry entry = createBatteryDiffEntry(10, new BatteryHistEntry(values));
 
         assertThat(entry.isSystemEntry()).isFalse();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.containsKey(UNINSTALLED_PACKAGE_NAME))
+                .isFalse();
         assertThat(entry.isUninstalledEntry()).isTrue();
+        assertThat(BatteryDiffEntry.sPackageNameAndUidCache.get(UNINSTALLED_PACKAGE_NAME))
+                .isEqualTo(BatteryUtils.UID_NULL);
     }
 
     @Test
@@ -590,7 +602,7 @@ public final class BatteryDiffEntryTest {
         final BatteryHistEntry batteryHistEntry = new BatteryHistEntry(values);
         doReturn(drawable).when(mMockPackageManager).getDefaultActivityIcon();
         doReturn(null).when(mMockPackageManager).getApplicationInfo("com.a.b.c", 0);
-        doReturn(new String[] {"com.a.b.c"}).when(mMockPackageManager).getPackagesForUid(1001);
+        doReturn(new String[]{"com.a.b.c"}).when(mMockPackageManager).getPackagesForUid(1001);
         return createBatteryDiffEntry(10, batteryHistEntry);
     }