From e14bda80851a137214ab2991e73e5a80ca9e2517 Mon Sep 17 00:00:00 2001
From: Yohei Yukawa <yukawa@google.com>
Date: Fri, 28 Dec 2018 13:21:52 -0800
Subject: [PATCH] Avoid unnecessary File.delete() for nonexistent directory

This is a follow up CL to my previous CL [1], which aimed to delete
/data/system/inputmethod/ when it's empty.

One thing I overlooked was the case where the directory does not exist
already.  In that case, further trying to delete such a nonexistent
directory simply failed hence resulted in outputting the following
error message to logcat.

  Failed to delete the empty parent directory /data/system/inputmethod

With this CL, the existence of /data/system/inputmethod/ will be
checked first to see if there is anything to clean up in the first
place.

[1]: I2307b5e4edf7b90d2fc03138f233d6051f80cf90
      b1a3fdb99f5c577227fe80298f01bfbeb01322ad

Bug: 121223050
Test: Manually verified as follows
  1. Build and flash aosp_taimen-userdebug into taimen
  2. Wait until the device fully boots up
  3. adb reboot  # to avoid Bug 121259290
  4. adb root
  5. adb shell cat /data/system/inputmethod/subtypes.xml
      -> make sure the content looks as follows:
         <subtypes>
           <imi id="com.android.inputmethod.latin/.LatinIME">
             <subtype ....>
             <subtype ....>
           </imi/>
         </subtypes>
  6. Open AOSP Keyboard settings
  7. Go to "Appearance & Layouts" -> "Custom input styles"
  8. Remove all layouts
  9. adb shell cat /data/system/inputmethod/subtypes.xml
      -> make sure the file no longer exists
 10. adb shell ls /data/system/inputmethod
      -> make sure the directory no longer exists
 11. adb reboot
 12. adb logcat -s InputMethodManagerService:*
      -> no error message about /data/system/inputmethod
Change-Id: I0428a1ec6300ef346503c53928ddbcf5bb38aab0
---
 .../server/inputmethod/InputMethodManagerService.java     | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
index ad0886145496a..99979c18b5201 100644
--- a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
+++ b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
@@ -4237,11 +4237,15 @@ public class InputMethodManagerService extends IInputMethodManager.Stub
                 ArrayMap<String, List<InputMethodSubtype>> allSubtypes, AtomicFile subtypesFile,
                 ArrayMap<String, InputMethodInfo> methodMap) {
             if (allSubtypes.isEmpty()) {
+                final File parentDir = subtypesFile.getBaseFile().getParentFile();
+                if (parentDir == null || !parentDir.exists()) {
+                    // Even the parent directory doesn't exist.  There is nothing to clean up.
+                    return;
+                }
                 if (subtypesFile.exists()) {
                     subtypesFile.delete();
                 }
-                final File parentDir = subtypesFile.getBaseFile().getParentFile();
-                if (parentDir != null && FileUtils.listFilesOrEmpty(parentDir).length == 0) {
+                if (FileUtils.listFilesOrEmpty(parentDir).length == 0) {
                     if (!parentDir.delete()) {
                         Slog.e(TAG, "Failed to delete the empty parent directory " + parentDir);
                     }