Allow defining replacement key events in keymap

Currently keyboard maps allow to assign character sequences to key
events and allow specifying a so-called "fallback" key events that are
re-injected into input stream if target application indicates that it
was not able to handle the original key event. Unfortunately there is no
way to perform substitution before handing the event to applicationis.

This change adds a new keymap keyword "replace" that allows users query
"replacement" actions for key (if any), with the intent that such
replacement happens early in the event handling process.

Bug: 24504154

Change-Id: I3e6a2476c856524171df00ad22ff56f2018c1278

1 files changed, 8 insertions, 0 deletions

diff --git a/include/input/KeyCharacterMap.h b/include/input/KeyCharacterMap.h
index e70666a..3f0914b 100644
--- a/include/input/KeyCharacterMap.h
+++ b/include/input/KeyCharacterMap.h
@@ -124,6 +124,11 @@ public:
      * the mapping in some way. */
     status_t mapKey(int32_t scanCode, int32_t usageCode, int32_t* outKeyCode) const;
 
+    /* Tries to find a replacement key code for a given key code and meta state
+     * in character map. */
+    void tryRemapKey(int32_t scanCode, int32_t metaState,
+            int32_t* outKeyCode, int32_t* outMetaState) const;
+
 #if HAVE_ANDROID_OS
     /* Reads a key map from a parcel. */
     static sp<KeyCharacterMap> readFromParcel(Parcel* parcel);
@@ -151,6 +156,9 @@ private:
 
         /* The fallback keycode if the key is not handled. */
         int32_t fallbackKeyCode;
+
+        /* The replacement keycode if the key has to be replaced outright. */
+        int32_t replacementKeyCode;
     };
 
     struct Key {