Clear applied layout overlay if new layout overlay is null.

Need to allow resetting of key character map by setting overlay
map to null. This is required when moving from a IME setting
that has a KCM to another IME setting that has none.

Test: atest KeyboardLayoutChangeTest
Bug: 20805588
Change-Id: I62dc65970b61628486aff698a8ab8ccb31c109d6

3 files changed, 16 insertions, 1 deletions

diff --git a/include/input/KeyCharacterMap.h b/include/input/KeyCharacterMap.h
index 867a08955c..b5e6f65e48 100644
--- a/include/input/KeyCharacterMap.h
+++ b/include/input/KeyCharacterMap.h
@@ -87,6 +87,9 @@ public:
     /* Combines this key character map with the provided overlay. */
     void combine(const KeyCharacterMap& overlay);
 
+    /* Clears already applied layout overlay */
+    void clearLayoutOverlay();
+
     /* Gets the keyboard type. */
     KeyboardType getKeyboardType() const;
 
diff --git a/libs/input/KeyCharacterMap.cpp b/libs/input/KeyCharacterMap.cpp
index fa5c41f657..6bfac40932 100644
--- a/libs/input/KeyCharacterMap.cpp
+++ b/libs/input/KeyCharacterMap.cpp
@@ -255,6 +255,13 @@ void KeyCharacterMap::combine(const KeyCharacterMap& overlay) {
     mLayoutOverlayApplied = true;
 }
 
+void KeyCharacterMap::clearLayoutOverlay() {
+    if (mLayoutOverlayApplied) {
+        reloadBaseFromFile();
+        mLayoutOverlayApplied = false;
+    }
+}
+
 KeyCharacterMap::KeyboardType KeyCharacterMap::getKeyboardType() const {
     return mType;
 }
diff --git a/services/inputflinger/reader/EventHub.cpp b/services/inputflinger/reader/EventHub.cpp
index b214750443..43b67cae8b 100644
--- a/services/inputflinger/reader/EventHub.cpp
+++ b/services/inputflinger/reader/EventHub.cpp
@@ -1416,12 +1416,17 @@ const std::shared_ptr<KeyCharacterMap> EventHub::getKeyCharacterMap(int32_t devi
     return nullptr;
 }
 
+// If provided map is null, it will reset key character map to default KCM.
 bool EventHub::setKeyboardLayoutOverlay(int32_t deviceId, std::shared_ptr<KeyCharacterMap> map) {
     std::scoped_lock _l(mLock);
     Device* device = getDeviceLocked(deviceId);
-    if (device == nullptr || map == nullptr || device->keyMap.keyCharacterMap == nullptr) {
+    if (device == nullptr || device->keyMap.keyCharacterMap == nullptr) {
         return false;
     }
+    if (map == nullptr) {
+        device->keyMap.keyCharacterMap->clearLayoutOverlay();
+        return true;
+    }
     device->keyMap.keyCharacterMap->combine(*map);
     return true;
 }