Add CursorAnchorInfoCompatWrapper for KitKat and older platforms

Change-Id: Ia26c783ebefd7b928d623a598792b7ba32d89a80

java/src/com/android/inputmethod/compat/CursorAnchorInfoCompatWrapper.java

+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.compat;
+
+import android.graphics.Matrix;
+import android.graphics.RectF;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+
+import java.lang.reflect.Method;
+
+@UsedForTesting
+public final class CursorAnchorInfoCompatWrapper {
+    // Note that CursorAnchorInfo has been introduced in API level XX (Build.VERSION_CODE.LXX).
+    private static Class<?> getCursorAnchorInfoClass() {
+        try {
+            return Class.forName("android.view.inputmethod.CursorAnchorInfo");
+        } catch (ClassNotFoundException e) {
+            return null;
+        }
+    }
+    private static final Class<?> CLASS;
+    private static final Method METHOD_GET_CHARACTER_RECT;
+    private static final Method METHOD_GET_CHARACTER_RECT_FLAGS;
+    private static final Method METHOD_GET_COMPOSING_TEXT;
+    private static final Method METHOD_GET_COMPOSING_TEXT_START;
+    private static final Method METHOD_GET_MATRIX;
+    static {
+        CLASS = getCursorAnchorInfoClass();
+        METHOD_GET_CHARACTER_RECT = CompatUtils.getMethod(CLASS, "getCharacterRect", int.class);
+        METHOD_GET_CHARACTER_RECT_FLAGS = CompatUtils.getMethod(CLASS, "getCharacterRectFlags",
+                int.class);
+        METHOD_GET_COMPOSING_TEXT = CompatUtils.getMethod(CLASS, "getComposingText");
+        METHOD_GET_COMPOSING_TEXT_START = CompatUtils.getMethod(CLASS, "getComposingTextStart");
+        METHOD_GET_MATRIX = CompatUtils.getMethod(CLASS, "getMatrix");
+    }
+
+    @UsedForTesting
+    public static boolean isAvailable() {
+        return CLASS != null;
+    }
+
+    public static final int CHARACTER_RECT_TYPE_MASK = 0x0f;
+
+    /**
+     * Type for {@link #CHARACTER_RECT_TYPE_MASK}: the editor did not specify any type of this
+     * character. Editor authors should not use this flag.
+     */
+    public static final int CHARACTER_RECT_TYPE_UNSPECIFIED = 0;
+
+    /**
+     * Type for {@link #CHARACTER_RECT_TYPE_MASK}: the character is entirely visible.
+     */
+    public static final int CHARACTER_RECT_TYPE_FULLY_VISIBLE = 1;
+
+    /**
+     * Type for {@link #CHARACTER_RECT_TYPE_MASK}: some area of the character is invisible.
+     */
+    public static final int CHARACTER_RECT_TYPE_PARTIALLY_VISIBLE = 2;
+
+    /**
+     * Type for {@link #CHARACTER_RECT_TYPE_MASK}: the character is entirely invisible.
+     */
+    public static final int CHARACTER_RECT_TYPE_INVISIBLE = 3;
+
+    /**
+     * Type for {@link #CHARACTER_RECT_TYPE_MASK}: the editor gave up to calculate the rectangle
+     * for this character. Input method authors should ignore the returned rectangle.
+     */
+    public static final int CHARACTER_RECT_TYPE_NOT_FEASIBLE = 4;
+
+    private Object mInstance;
+
+    private CursorAnchorInfoCompatWrapper(final Object instance) {
+        mInstance = instance;
+    }
+
+    @UsedForTesting
+    public static CursorAnchorInfoCompatWrapper fromObject(final Object instance) {
+        if (!isAvailable()) {
+            return new CursorAnchorInfoCompatWrapper(null);
+        }
+        return new CursorAnchorInfoCompatWrapper(instance);
+    }
+
+    private static final class FakeHolder {
+        static CursorAnchorInfoCompatWrapper sInstance = new CursorAnchorInfoCompatWrapper(null);
+    }
+
+    @UsedForTesting
+    public static CursorAnchorInfoCompatWrapper getFake() {
+        return FakeHolder.sInstance;
+    }
+
+    public CharSequence getComposingText() {
+        return (CharSequence) CompatUtils.invoke(mInstance, null, METHOD_GET_COMPOSING_TEXT);
+    }
+
+    private static int COMPOSING_TEXT_START_DEFAULT = -1;
+    public int getComposingTextStart() {
+        if (mInstance == null || METHOD_GET_COMPOSING_TEXT_START == null) {
+            return COMPOSING_TEXT_START_DEFAULT;
+        }
+        return (int) CompatUtils.invoke(mInstance, null, METHOD_GET_COMPOSING_TEXT_START);
+    }
+
+    public Matrix getMatrix() {
+        return (Matrix) CompatUtils.invoke(mInstance, null, METHOD_GET_MATRIX);
+    }
+
+    public RectF getCharacterRect(final int index) {
+        return (RectF) CompatUtils.invoke(mInstance, null, METHOD_GET_CHARACTER_RECT, index);
+    }
+
+    public int getCharacterRectFlags(final int index) {
+        if (mInstance == null || METHOD_GET_CHARACTER_RECT_FLAGS == null) {
+            return CHARACTER_RECT_TYPE_UNSPECIFIED;
+        }
+        return (int) CompatUtils.invoke(mInstance, null, METHOD_GET_CHARACTER_RECT_FLAGS, index);
+    }
+}