Cache subtype lists reasonably.

This will spare a lot of IPC for Latin IME at the cost of very little
retained memory.
This improves the loading by potentially a lot - between 15 and 30%
when the layout is cached (which should now be the case almost every
time), and half that if it's not. More importantly, it makes the
load time less sensitive to high device load, which is one of the
sore points.

Bug: 8689779
Change-Id: I2e07736f1a92c38eed0e203bc690761a181da8b9

1 files changed, 33 insertions, 9 deletions

diff --git a/java/src/com/android/inputmethod/latin/RichInputMethodManager.java b/java/src/com/android/inputmethod/latin/RichInputMethodManager.java
index 94513e635..86f75635d 100644
--- a/java/src/com/android/inputmethod/latin/RichInputMethodManager.java
+++ b/java/src/com/android/inputmethod/latin/RichInputMethodManager.java
@@ -30,6 +30,7 @@ import android.view.inputmethod.InputMethodSubtype;
 import com.android.inputmethod.compat.InputMethodManagerCompatWrapper;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 
 /**
@@ -46,6 +47,10 @@ public final class RichInputMethodManager {
 
     private InputMethodManagerCompatWrapper mImmWrapper;
     private InputMethodInfo mInputMethodInfoOfThisIme;
+    final HashMap<InputMethodInfo, List<InputMethodSubtype>>
+            mSubtypeListCacheWithImplicitlySelectedSubtypes = CollectionUtils.newHashMap();
+    final HashMap<InputMethodInfo, List<InputMethodSubtype>>
+            mSubtypeListCacheWithoutImplicitlySelectedSubtypes = CollectionUtils.newHashMap();
 
     private static final int INDEX_NOT_FOUND = -1;
 
@@ -102,8 +107,8 @@ public final class RichInputMethodManager {
 
     public List<InputMethodSubtype> getMyEnabledInputMethodSubtypeList(
             boolean allowsImplicitlySelectedSubtypes) {
-        return mImmWrapper.mImm.getEnabledInputMethodSubtypeList(
-                mInputMethodInfoOfThisIme, allowsImplicitlySelectedSubtypes);
+        return getEnabledInputMethodSubtypeList(mInputMethodInfoOfThisIme,
+                allowsImplicitlySelectedSubtypes);
     }
 
     public boolean switchToNextInputMethod(final IBinder token, final boolean onlyCurrentIme) {
@@ -151,8 +156,8 @@ public final class RichInputMethodManager {
             return false;
         }
         final InputMethodInfo nextImi = getNextNonAuxiliaryIme(currentIndex, enabledImis);
-        final List<InputMethodSubtype> enabledSubtypes = imm.getEnabledInputMethodSubtypeList(
-                nextImi, true /* allowsImplicitlySelectedSubtypes */);
+        final List<InputMethodSubtype> enabledSubtypes = getEnabledInputMethodSubtypeList(nextImi,
+                true /* allowsImplicitlySelectedSubtypes */);
         if (enabledSubtypes.isEmpty()) {
             // The next IME has no subtype.
             imm.setInputMethod(token, nextImi.getId());
@@ -227,9 +232,8 @@ public final class RichInputMethodManager {
 
     public boolean checkIfSubtypeBelongsToImeAndEnabled(final InputMethodInfo imi,
             final InputMethodSubtype subtype) {
-        return checkIfSubtypeBelongsToList(
-                subtype, mImmWrapper.mImm.getEnabledInputMethodSubtypeList(
-                        imi, true /* allowsImplicitlySelectedSubtypes */));
+        return checkIfSubtypeBelongsToList(subtype, getEnabledInputMethodSubtypeList(imi,
+                true /* allowsImplicitlySelectedSubtypes */));
     }
 
     private static boolean checkIfSubtypeBelongsToList(final InputMethodSubtype subtype,
@@ -290,8 +294,7 @@ public final class RichInputMethodManager {
         for (InputMethodInfo imi : imiList) {
             // We can return true immediately after we find two or more filtered IMEs.
             if (filteredImisCount > 1) return true;
-            final List<InputMethodSubtype> subtypes =
-                    mImmWrapper.mImm.getEnabledInputMethodSubtypeList(imi, true);
+            final List<InputMethodSubtype> subtypes = getEnabledInputMethodSubtypeList(imi, true);
             // IMEs that have no subtypes should be counted.
             if (subtypes.isEmpty()) {
                 ++filteredImisCount;
@@ -354,5 +357,26 @@ public final class RichInputMethodManager {
     public void setAdditionalInputMethodSubtypes(final InputMethodSubtype[] subtypes) {
         mImmWrapper.mImm.setAdditionalInputMethodSubtypes(
                 mInputMethodInfoOfThisIme.getId(), subtypes);
+        // Clear the cache so that we go read the subtypes again next time.
+        clearSubtypeCaches();
+    }
+
+    private List<InputMethodSubtype> getEnabledInputMethodSubtypeList(final InputMethodInfo imi,
+            final boolean allowsImplicitlySelectedSubtypes) {
+        final HashMap<InputMethodInfo, List<InputMethodSubtype>> cache =
+                allowsImplicitlySelectedSubtypes
+                ? mSubtypeListCacheWithImplicitlySelectedSubtypes
+                : mSubtypeListCacheWithoutImplicitlySelectedSubtypes;
+        final List<InputMethodSubtype> cachedList = cache.get(imi);
+        if (null != cachedList) return cachedList;
+        final List<InputMethodSubtype> result = mImmWrapper.mImm.getEnabledInputMethodSubtypeList(
+                imi, allowsImplicitlySelectedSubtypes);
+        cache.put(imi, result);
+        return result;
+    }
+
+    public void clearSubtypeCaches() {
+        mSubtypeListCacheWithImplicitlySelectedSubtypes.clear();
+        mSubtypeListCacheWithoutImplicitlySelectedSubtypes.clear();
     }
 }