1 files changed, 43 insertions, 1 deletions
diff --git a/java/src/com/android/inputmethod/latin/RichInputConnection.java b/java/src/com/android/inputmethod/latin/RichInputConnection.java
index 37e1dbb69..43b9ba7a9 100644
--- a/java/src/com/android/inputmethod/latin/RichInputConnection.java
+++ b/java/src/com/android/inputmethod/latin/RichInputConnection.java
@@ -192,7 +192,19 @@ public class RichInputConnection {
     public int getCursorCapsMode(final int inputType) {
         mIC = mParent.getCurrentInputConnection();
         if (null == mIC) return Constants.TextUtils.CAP_MODE_OFF;
-        return mIC.getCursorCapsMode(inputType);
+        if (!TextUtils.isEmpty(mComposingText)) return Constants.TextUtils.CAP_MODE_OFF;
+        // TODO: this will generally work, but there may be cases where the buffer contains SOME
+        // information but not enough to determine the caps mode accurately. This may happen after
+        // heavy pressing of delete, for example DEFAULT_TEXT_CACHE_SIZE - 5 times or so.
+        // getCapsMode should be updated to be able to return a "not enough info" result so that
+        // we can get more context only when needed.
+        if (TextUtils.isEmpty(mCommittedTextBeforeComposingText) && 0 != mCurrentCursorPosition) {
+            mCommittedTextBeforeComposingText.append(
+                    getTextBeforeCursor(DEFAULT_TEXT_CACHE_SIZE, 0));
+        }
+        // This never calls InputConnection#getCapsMode - in fact, it's a static method that
+        // never blocks or initiates IPC.
+        return StringUtils.getCapsMode(mCommittedTextBeforeComposingText, inputType);
     }
 
     public CharSequence getTextBeforeCursor(final int i, final int j) {
@@ -629,4 +641,34 @@ public class RichInputConnection {
         commitText(" " + textBeforeCursor.subSequence(0, 1), 1);
         return true;
     }
+
+    /**
+     * Heuristic to determine if this is an expected update of the cursor.
+     *
+     * Sometimes updates to the cursor position are late because of their asynchronous nature.
+     * This method tries to determine if this update is one, based on the values of the cursor
+     * position in the update, and the currently expected position of the cursor according to
+     * LatinIME's internal accounting. If this is not a belated expected update, then it should
+     * mean that the user moved the cursor explicitly.
+     * This is quite robust, but of course it's not perfect. In particular, it will fail in the
+     * case we get an update A, the user types in N characters so as to move the cursor to A+N but
+     * we don't get those, and then the user places the cursor between A and A+N, and we get only
+     * this update and not the ones in-between. This is almost impossible to achieve even trying
+     * very very hard.
+     *
+     * @param oldSelStart The value of the old cursor position in the update.
+     * @param newSelStart The value of the new cursor position in the update.
+     * @return whether this is a belated expected update or not.
+     */
+    public boolean isBelatedExpectedUpdate(final int oldSelStart, final int newSelStart) {
+        // If this is an update that arrives at our expected position, it's a belated update.
+        if (newSelStart == mCurrentCursorPosition) return true;
+        // If this is an update that moves the cursor from our expected position, it must be
+        // an explicit move.
+        if (oldSelStart == mCurrentCursorPosition) return false;
+        // The following returns true if newSelStart is between oldSelStart and
+        // mCurrentCursorPosition. We assume that if the updated position is between the old
+        // position and the expected position, then it must be a belated update.
+        return (newSelStart - oldSelStart) * (mCurrentCursorPosition - newSelStart) >= 0;
+    }
 }