1 files changed, 194 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/latin/EditingUtil.java b/java/src/com/android/inputmethod/latin/EditingUtil.java
new file mode 100644
index 000000000..5133c60ca
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/EditingUtil.java
@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2009 Google Inc.
+ * 
+ * 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.latin;
+
+import java.util.regex.Pattern;
+
+import android.view.inputmethod.ExtractedText;
+import android.view.inputmethod.ExtractedTextRequest;
+import android.view.inputmethod.InputConnection;
+
+/**
+ * Utility methods to deal with editing text through an InputConnection.
+ */
+public class EditingUtil {
+    /**
+     * Number of characters we want to look back in order to identify the previous word
+     */
+    public static final int LOOKBACK_CHARACTER_NUM = 15;
+
+    private EditingUtil() {};
+
+    /**
+     * Append newText to the text field represented by connection.
+     * The new text becomes selected.
+     */
+    public static void appendText(InputConnection connection, String newText) {
+        if (connection == null) {
+            return;
+        }
+
+        // Commit the composing text
+        connection.finishComposingText();
+
+        // Add a space if the field already has text.
+        CharSequence charBeforeCursor = connection.getTextBeforeCursor(1, 0);
+        if (charBeforeCursor != null
+                && !charBeforeCursor.equals(" ")
+                && (charBeforeCursor.length() > 0)) {
+            newText = " " + newText;
+        }
+
+        connection.setComposingText(newText, 1);
+    }
+
+    private static int getCursorPosition(InputConnection connection) {
+        ExtractedText extracted = connection.getExtractedText(
+            new ExtractedTextRequest(), 0);
+        if (extracted == null) {
+          return -1;
+        }
+        return extracted.startOffset + extracted.selectionStart;
+    }
+
+    private static int getSelectionEnd(InputConnection connection) {
+        ExtractedText extracted = connection.getExtractedText(
+            new ExtractedTextRequest(), 0);
+        if (extracted == null) {
+          return -1;
+        }
+        return extracted.startOffset + extracted.selectionEnd;
+    }
+
+    /**
+     * @param connection connection to the current text field.
+     * @param sep characters which may separate words
+     * @return the word that surrounds the cursor, including up to one trailing
+     *   separator. For example, if the field contains "he|llo world", where |
+     *   represents the cursor, then "hello " will be returned.
+     */
+    public static String getWordAtCursor(
+            InputConnection connection, String separators) {
+        return getWordAtCursor(connection, separators, null);
+    }
+
+    /**
+     * @param connection connection to the current text field.
+     * @param sep characters which may separate words
+     * @return the word that surrounds the cursor, including up to one trailing
+     *   separator. For example, if the field contains "he|llo world", where |
+     *   represents the cursor, then "hello " will be returned.
+     */
+    public static String getWordAtCursor(
+        InputConnection connection, String separators, Range range) {
+        Range r = getWordRangeAtCursor(connection, separators, range);
+        return (r == null) ? null : r.word;
+    }
+
+    /**
+     * Removes the word surrounding the cursor. Parameters are identical to
+     * getWordAtCursor.
+     */
+    public static void deleteWordAtCursor(
+        InputConnection connection, String separators) {
+
+        Range range = getWordRangeAtCursor(connection, separators, null);
+        if (range == null) return;
+
+        connection.finishComposingText();
+        // Move cursor to beginning of word, to avoid crash when cursor is outside
+        // of valid range after deleting text.
+        int newCursor = getCursorPosition(connection) - range.charsBefore;
+        connection.setSelection(newCursor, newCursor);
+        connection.deleteSurroundingText(0, range.charsBefore + range.charsAfter);
+    }
+
+    /**
+     * Represents a range of text, relative to the current cursor position.
+     */
+    public static class Range {
+        /** Characters before selection start */
+        public int charsBefore;
+
+        /**
+         * Characters after selection start, including one trailing word
+         * separator.
+         */
+        public int charsAfter;
+
+        /** The actual characters that make up a word */
+        public String word;
+
+        public Range() {}
+
+        public Range(int charsBefore, int charsAfter, String word) {
+            if (charsBefore < 0 || charsAfter < 0) {
+                throw new IndexOutOfBoundsException();
+            }
+            this.charsBefore = charsBefore;
+            this.charsAfter = charsAfter;
+            this.word = word;
+        }
+    }
+
+    private static Range getWordRangeAtCursor(
+            InputConnection connection, String sep, Range range) {
+        if (connection == null || sep == null) {
+            return null;
+        }
+        CharSequence before = connection.getTextBeforeCursor(1000, 0);
+        CharSequence after = connection.getTextAfterCursor(1000, 0);
+        if (before == null || after == null) {
+            return null;
+        }
+
+        // Find first word separator before the cursor
+        int start = before.length();
+        while (start > 0 && !isWhitespace(before.charAt(start - 1), sep)) start--;
+
+        // Find last word separator after the cursor
+        int end = -1;
+        while (++end < after.length() && !isWhitespace(after.charAt(end), sep));
+
+        int cursor = getCursorPosition(connection);
+        if (start >= 0 && cursor + end <= after.length() + before.length()) {
+            String word = before.toString().substring(start, before.length())
+                    + after.toString().substring(0, end);
+
+            Range returnRange = range != null? range : new Range();
+            returnRange.charsBefore = before.length() - start;
+            returnRange.charsAfter = end;
+            returnRange.word = word;
+            return returnRange;
+        }
+
+        return null;
+    }
+
+    private static boolean isWhitespace(int code, String whitespace) {
+        return whitespace.contains(String.valueOf((char) code));
+    }
+
+    private static final Pattern spaceRegex = Pattern.compile("\\s+");
+
+    public static CharSequence getPreviousWord(InputConnection connection) {
+        //TODO: Should fix this. This could be slow!
+        CharSequence prev = connection.getTextBeforeCursor(LOOKBACK_CHARACTER_NUM, 0);
+        String[] w = spaceRegex.split(prev);
+        return (w.length >= 2) ? w[w.length-2] : null;
+    }
+}