From 3fa28af449d2dab6abcff9049ef4c29d30367db3 Mon Sep 17 00:00:00 2001
From: Nikolas Havrikov <havrikov@google.com>
Date: Tue, 25 Oct 2022 09:45:42 +0200
Subject: Replace HashMap with ArrayMap in AppsFilterImpl

This saves memory in the system_server.
Additionally, this CL replaces iterators with for loops using
valueAt() to save further memory.

Test: adb shell am dumpheap `adb shell pidof system_server`
Test: then use ahat to manually inspect: http://screen/3dVis7RNst2SJp8
Bug: 254230758
Change-Id: Iada8859e7c04f6dde2d7d1fbc0ab730d6e035770
---
 .../java/com/android/server/pm/AppsFilterImpl.java | 25 ++++++++++++----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/services/core/java/com/android/server/pm/AppsFilterImpl.java b/services/core/java/com/android/server/pm/AppsFilterImpl.java
index 4c21195e2890..e5b8372ea7b3 100644
--- a/services/core/java/com/android/server/pm/AppsFilterImpl.java
+++ b/services/core/java/com/android/server/pm/AppsFilterImpl.java
@@ -71,11 +71,8 @@ import com.android.server.utils.Watcher;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
-import java.util.Set;
 
 /**
  * Implementation of the methods that update the internal structures of AppsFilter. Because of the
@@ -103,7 +100,7 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
      */
     @GuardedBy("mQueryableViaUsesPermissionLock")
     @NonNull
-    private HashMap<String, Set<Integer>> mPermissionToUids;
+    private final ArrayMap<String, ArraySet<Integer>> mPermissionToUids;
 
     /**
      * A cache that maps parsed {@link android.R.styleable#AndroidManifestUsesPermission
@@ -113,7 +110,7 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
      */
     @GuardedBy("mQueryableViaUsesPermissionLock")
     @NonNull
-    private HashMap<String, Set<Integer>> mUsesPermissionToUids;
+    private final ArrayMap<String, ArraySet<Integer>> mUsesPermissionToUids;
 
     /**
      * Ensures an observer is in the list, exactly once. The observer cannot be null.  The
@@ -215,8 +212,8 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
         mProtectedBroadcasts = new WatchedArrayList<>();
         mProtectedBroadcastsSnapshot = new SnapshotCache.Auto<>(
                 mProtectedBroadcasts, mProtectedBroadcasts, "AppsFilter.mProtectedBroadcasts");
-        mPermissionToUids = new HashMap<>();
-        mUsesPermissionToUids = new HashMap<>();
+        mPermissionToUids = new ArrayMap<>();
+        mUsesPermissionToUids = new ArrayMap<>();
 
         mSnapshot = new SnapshotCache<AppsFilterSnapshot>(this, this) {
             @Override
@@ -578,7 +575,10 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
                     // Lookup in the mPermissionToUids cache if installed packages have
                     // defined this permission.
                     if (mPermissionToUids.containsKey(usesPermissionName)) {
-                        for (int targetAppId : mPermissionToUids.get(usesPermissionName)) {
+                        final ArraySet<Integer> permissionDefiners =
+                                mPermissionToUids.get(usesPermissionName);
+                        for (int j = 0; j < permissionDefiners.size(); j++) {
+                            final int targetAppId = permissionDefiners.valueAt(j);
                             if (targetAppId != newPkgSetting.getAppId()) {
                                 mQueryableViaUsesPermission.add(newPkgSetting.getAppId(),
                                         targetAppId);
@@ -588,7 +588,7 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
                     // Record in mUsesPermissionToUids that a permission was requested
                     // by a new package
                     if (!mUsesPermissionToUids.containsKey(usesPermissionName)) {
-                        mUsesPermissionToUids.put(usesPermissionName, new HashSet<>());
+                        mUsesPermissionToUids.put(usesPermissionName, new ArraySet<>());
                     }
                     mUsesPermissionToUids.get(usesPermissionName).add(newPkgSetting.getAppId());
                 }
@@ -602,7 +602,10 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
                     // Lookup in the mUsesPermissionToUids cache if installed packages have
                     // requested this permission.
                     if (mUsesPermissionToUids.containsKey(permissionName)) {
-                        for (int queryingAppId : mUsesPermissionToUids.get(permissionName)) {
+                        final ArraySet<Integer> permissionUsers = mUsesPermissionToUids.get(
+                                permissionName);
+                        for (int j = 0; j < permissionUsers.size(); j++) {
+                            final int queryingAppId = permissionUsers.valueAt(j);
                             if (queryingAppId != newPkgSetting.getAppId()) {
                                 mQueryableViaUsesPermission.add(queryingAppId,
                                         newPkgSetting.getAppId());
@@ -611,7 +614,7 @@ public final class AppsFilterImpl extends AppsFilterLocked implements Watchable,
                     }
                     // Record in mPermissionToUids that a permission was defined by a new package
                     if (!mPermissionToUids.containsKey(permissionName)) {
-                        mPermissionToUids.put(permissionName, new HashSet<>());
+                        mPermissionToUids.put(permissionName, new ArraySet<>());
                     }
                     mPermissionToUids.get(permissionName).add(newPkgSetting.getAppId());
                 }
-- 
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