From 2fe2dbca530fba05e4b10ee5f088ffbdd9f4bdd2 Mon Sep 17 00:00:00 2001
From: Yohei Yukawa <yukawa@google.com>
Date: Wed, 19 Dec 2018 14:12:35 -0800
Subject: [PATCH] Let the absence of subtype.xml mean there is no additional
 subtype

Historically, we have always created a stub subtype.xml for each user
even when there is no additional subtype.  Instead of having such a
stub XML files, no subtype will be represented by the absence of
subtype.xml with this CL.

If there has already been such a stub XML, it will be deleted
automatically when
InputMethodFileManager#writeAdditionalInputMethodSubtypes() gets
called next time.  Note that this method is called from
InputMethodManagerService#onFinishPackageChangesInternal(), which is
called when some IME package is updated.

This is completely about how internal data is persisted.  There should
be no developer-visible behavior change.

Fix: 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
Change-Id: If06e1b5967443157d1a7606190d721ae8983be08
---
 .../InputMethodManagerService.java            | 21 ++++++++++++-------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
index 47c5f492a7e09..597d81ffab5c6 100644
--- a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
+++ b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
@@ -4304,14 +4304,8 @@ public class InputMethodManagerService extends IInputMethodManager.Stub
             }
             final File subtypeFile = new File(inputMethodDir, ADDITIONAL_SUBTYPES_FILE_NAME);
             mAdditionalInputMethodSubtypeFile = new AtomicFile(subtypeFile, "input-subtypes");
-            if (!subtypeFile.exists()) {
-                // If "subtypes.xml" doesn't exist, create a blank file.
-                writeAdditionalInputMethodSubtypes(
-                        mAdditionalSubtypesMap, mAdditionalInputMethodSubtypeFile, methodMap);
-            } else {
-                readAdditionalInputMethodSubtypes(
-                        mAdditionalSubtypesMap, mAdditionalInputMethodSubtypeFile);
-            }
+            readAdditionalInputMethodSubtypes(mAdditionalSubtypesMap,
+                    mAdditionalInputMethodSubtypeFile);
         }
 
         private void deleteAllInputMethodSubtypes(String imiId) {
@@ -4351,6 +4345,13 @@ public class InputMethodManagerService extends IInputMethodManager.Stub
         private static void writeAdditionalInputMethodSubtypes(
                 ArrayMap<String, List<InputMethodSubtype>> allSubtypes, AtomicFile subtypesFile,
                 ArrayMap<String, InputMethodInfo> methodMap) {
+            if (allSubtypes.isEmpty()) {
+                if (subtypesFile.exists()) {
+                    subtypesFile.delete();
+                }
+                return;
+            }
+
             // Safety net for the case that this function is called before methodMap is set.
             final boolean isSetMethodMap = methodMap != null && methodMap.size() > 0;
             FileOutputStream fos = null;
@@ -4407,6 +4408,10 @@ public class InputMethodManagerService extends IInputMethodManager.Stub
                 ArrayMap<String, List<InputMethodSubtype>> allSubtypes, AtomicFile subtypesFile) {
             if (allSubtypes == null || subtypesFile == null) return;
             allSubtypes.clear();
+            if (!subtypesFile.exists()) {
+                // Not having the file means there is no additional subtype.
+                return;
+            }
             try (final FileInputStream fis = subtypesFile.openRead()) {
                 final XmlPullParser parser = Xml.newPullParser();
                 parser.setInput(fis, StandardCharsets.UTF_8.name());