1 /*
2  * Copyright (C) 2012 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.inputmethod.latin;
18 
19 import android.inputmethodservice.InputMethodService;
20 import android.os.Build;
21 import android.os.Bundle;
22 import android.os.SystemClock;
23 import android.text.SpannableStringBuilder;
24 import android.text.TextUtils;
25 import android.text.style.CharacterStyle;
26 import android.util.Log;
27 import android.view.KeyEvent;
28 import android.view.inputmethod.CompletionInfo;
29 import android.view.inputmethod.CorrectionInfo;
30 import android.view.inputmethod.ExtractedText;
31 import android.view.inputmethod.ExtractedTextRequest;
32 import android.view.inputmethod.InputConnection;
33 import android.view.inputmethod.InputMethodManager;
34 
35 import com.android.inputmethod.compat.InputConnectionCompatUtils;
36 import com.android.inputmethod.latin.common.Constants;
37 import com.android.inputmethod.latin.common.UnicodeSurrogate;
38 import com.android.inputmethod.latin.common.StringUtils;
39 import com.android.inputmethod.latin.inputlogic.PrivateCommandPerformer;
40 import com.android.inputmethod.latin.settings.SpacingAndPunctuations;
41 import com.android.inputmethod.latin.utils.CapsModeUtils;
42 import com.android.inputmethod.latin.utils.DebugLogUtils;
43 import com.android.inputmethod.latin.utils.NgramContextUtils;
44 import com.android.inputmethod.latin.utils.ScriptUtils;
45 import com.android.inputmethod.latin.utils.SpannableStringUtils;
46 import com.android.inputmethod.latin.utils.StatsUtils;
47 import com.android.inputmethod.latin.utils.TextRange;
48 
49 import java.util.concurrent.TimeUnit;
50 
51 import javax.annotation.Nonnull;
52 import javax.annotation.Nullable;
53 
54 /**
55  * Enrichment class for InputConnection to simplify interaction and add functionality.
56  *
57  * This class serves as a wrapper to be able to simply add hooks to any calls to the underlying
58  * InputConnection. It also keeps track of a number of things to avoid having to call upon IPC
59  * all the time to find out what text is in the buffer, when we need it to determine caps mode
60  * for example.
61  */
62 public final class RichInputConnection implements PrivateCommandPerformer {
63     private static final String TAG = "RichInputConnection";
64     private static final boolean DBG = false;
65     private static final boolean DEBUG_PREVIOUS_TEXT = false;
66     private static final boolean DEBUG_BATCH_NESTING = false;
67     private static final int NUM_CHARS_TO_GET_BEFORE_CURSOR = 40;
68     private static final int NUM_CHARS_TO_GET_AFTER_CURSOR = 40;
69     private static final int INVALID_CURSOR_POSITION = -1;
70 
71     /**
72      * The amount of time a {@link #reloadTextCache} call needs to take for the keyboard to enter
73      * the {@link #hasSlowInputConnection} state.
74      */
75     private static final long SLOW_INPUT_CONNECTION_ON_FULL_RELOAD_MS = 1000;
76     /**
77      * The amount of time a {@link #getTextBeforeCursor} or {@link #getTextAfterCursor} call needs
78      * to take for the keyboard to enter the {@link #hasSlowInputConnection} state.
79      */
80     private static final long SLOW_INPUT_CONNECTION_ON_PARTIAL_RELOAD_MS = 200;
81 
82     private static final int OPERATION_GET_TEXT_BEFORE_CURSOR = 0;
83     private static final int OPERATION_GET_TEXT_AFTER_CURSOR = 1;
84     private static final int OPERATION_GET_WORD_RANGE_AT_CURSOR = 2;
85     private static final int OPERATION_RELOAD_TEXT_CACHE = 3;
86     private static final String[] OPERATION_NAMES = new String[] {
87             "GET_TEXT_BEFORE_CURSOR",
88             "GET_TEXT_AFTER_CURSOR",
89             "GET_WORD_RANGE_AT_CURSOR",
90             "RELOAD_TEXT_CACHE"};
91 
92     /**
93      * The amount of time the keyboard will persist in the {@link #hasSlowInputConnection} state
94      * after observing a slow InputConnection event.
95      */
96     private static final long SLOW_INPUTCONNECTION_PERSIST_MS = TimeUnit.MINUTES.toMillis(10);
97 
98     /**
99      * This variable contains an expected value for the selection start position. This is where the
100      * cursor or selection start may end up after all the keyboard-triggered updates have passed. We
101      * keep this to compare it to the actual selection start to guess whether the move was caused by
102      * a keyboard command or not.
103      * It's not really the selection start position: the selection start may not be there yet, and
104      * in some cases, it may never arrive there.
105      */
106     private int mExpectedSelStart = INVALID_CURSOR_POSITION; // in chars, not code points
107     /**
108      * The expected selection end.  Only differs from mExpectedSelStart if a non-empty selection is
109      * expected.  The same caveats as mExpectedSelStart apply.
110      */
111     private int mExpectedSelEnd = INVALID_CURSOR_POSITION; // in chars, not code points
112     /**
113      * This contains the committed text immediately preceding the cursor and the composing
114      * text, if any. It is refreshed when the cursor moves by calling upon the TextView.
115      */
116     private final StringBuilder mCommittedTextBeforeComposingText = new StringBuilder();
117     /**
118      * This contains the currently composing text, as LatinIME thinks the TextView is seeing it.
119      */
120     private final StringBuilder mComposingText = new StringBuilder();
121 
122     /**
123      * This variable is a temporary object used in {@link #commitText(CharSequence,int)}
124      * to avoid object creation.
125      */
126     private SpannableStringBuilder mTempObjectForCommitText = new SpannableStringBuilder();
127 
128     private final InputMethodService mParent;
129     private InputConnection mIC;
130     private int mNestLevel;
131 
132     /**
133      * The timestamp of the last slow InputConnection operation
134      */
135     private long mLastSlowInputConnectionTime = -SLOW_INPUTCONNECTION_PERSIST_MS;
136 
RichInputConnection(final InputMethodService parent)137     public RichInputConnection(final InputMethodService parent) {
138         mParent = parent;
139         mIC = null;
140         mNestLevel = 0;
141     }
142 
isConnected()143     public boolean isConnected() {
144         return mIC != null;
145     }
146 
147     /**
148      * Returns whether or not the underlying InputConnection is slow. When true, we want to avoid
149      * calling InputConnection methods that trigger an IPC round-trip (e.g., getTextAfterCursor).
150      */
hasSlowInputConnection()151     public boolean hasSlowInputConnection() {
152         return (SystemClock.uptimeMillis() - mLastSlowInputConnectionTime)
153                         <= SLOW_INPUTCONNECTION_PERSIST_MS;
154     }
155 
onStartInput()156     public void onStartInput() {
157         mLastSlowInputConnectionTime = -SLOW_INPUTCONNECTION_PERSIST_MS;
158     }
159 
checkConsistencyForDebug()160     private void checkConsistencyForDebug() {
161         final ExtractedTextRequest r = new ExtractedTextRequest();
162         r.hintMaxChars = 0;
163         r.hintMaxLines = 0;
164         r.token = 1;
165         r.flags = 0;
166         final ExtractedText et = mIC.getExtractedText(r, 0);
167         final CharSequence beforeCursor = getTextBeforeCursor(Constants.EDITOR_CONTENTS_CACHE_SIZE,
168                 0);
169         final StringBuilder internal = new StringBuilder(mCommittedTextBeforeComposingText)
170                 .append(mComposingText);
171         if (null == et || null == beforeCursor) return;
172         final int actualLength = Math.min(beforeCursor.length(), internal.length());
173         if (internal.length() > actualLength) {
174             internal.delete(0, internal.length() - actualLength);
175         }
176         final String reference = (beforeCursor.length() <= actualLength) ? beforeCursor.toString()
177                 : beforeCursor.subSequence(beforeCursor.length() - actualLength,
178                         beforeCursor.length()).toString();
179         if (et.selectionStart != mExpectedSelStart
180                 || !(reference.equals(internal.toString()))) {
181             final String context = "Expected selection start = " + mExpectedSelStart
182                     + "\nActual selection start = " + et.selectionStart
183                     + "\nExpected text = " + internal.length() + " " + internal
184                     + "\nActual text = " + reference.length() + " " + reference;
185             ((LatinIME)mParent).debugDumpStateAndCrashWithException(context);
186         } else {
187             Log.e(TAG, DebugLogUtils.getStackTrace(2));
188             Log.e(TAG, "Exp <> Actual : " + mExpectedSelStart + " <> " + et.selectionStart);
189         }
190     }
191 
beginBatchEdit()192     public void beginBatchEdit() {
193         if (++mNestLevel == 1) {
194             mIC = mParent.getCurrentInputConnection();
195             if (isConnected()) {
196                 mIC.beginBatchEdit();
197             }
198         } else {
199             if (DBG) {
200                 throw new RuntimeException("Nest level too deep");
201             }
202             Log.e(TAG, "Nest level too deep : " + mNestLevel);
203         }
204         if (DEBUG_BATCH_NESTING) checkBatchEdit();
205         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
206     }
207 
endBatchEdit()208     public void endBatchEdit() {
209         if (mNestLevel <= 0) Log.e(TAG, "Batch edit not in progress!"); // TODO: exception instead
210         if (--mNestLevel == 0 && isConnected()) {
211             mIC.endBatchEdit();
212         }
213         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
214     }
215 
216     /**
217      * Reset the cached text and retrieve it again from the editor.
218      *
219      * This should be called when the cursor moved. It's possible that we can't connect to
220      * the application when doing this; notably, this happens sometimes during rotation, probably
221      * because of a race condition in the framework. In this case, we just can't retrieve the
222      * data, so we empty the cache and note that we don't know the new cursor position, and we
223      * return false so that the caller knows about this and can retry later.
224      *
225      * @param newSelStart the new position of the selection start, as received from the system.
226      * @param newSelEnd the new position of the selection end, as received from the system.
227      * @param shouldFinishComposition whether we should finish the composition in progress.
228      * @return true if we were able to connect to the editor successfully, false otherwise. When
229      *   this method returns false, the caches could not be correctly refreshed so they were only
230      *   reset: the caller should try again later to return to normal operation.
231      */
resetCachesUponCursorMoveAndReturnSuccess(final int newSelStart, final int newSelEnd, final boolean shouldFinishComposition)232     public boolean resetCachesUponCursorMoveAndReturnSuccess(final int newSelStart,
233             final int newSelEnd, final boolean shouldFinishComposition) {
234         mExpectedSelStart = newSelStart;
235         mExpectedSelEnd = newSelEnd;
236         mComposingText.setLength(0);
237         final boolean didReloadTextSuccessfully = reloadTextCache();
238         if (!didReloadTextSuccessfully) {
239             Log.d(TAG, "Will try to retrieve text later.");
240             return false;
241         }
242         if (isConnected() && shouldFinishComposition) {
243             mIC.finishComposingText();
244         }
245         return true;
246     }
247 
248     /**
249      * Reload the cached text from the InputConnection.
250      *
251      * @return true if successful
252      */
reloadTextCache()253     private boolean reloadTextCache() {
254         mCommittedTextBeforeComposingText.setLength(0);
255         mIC = mParent.getCurrentInputConnection();
256         // Call upon the inputconnection directly since our own method is using the cache, and
257         // we want to refresh it.
258         final CharSequence textBeforeCursor = getTextBeforeCursorAndDetectLaggyConnection(
259                 OPERATION_RELOAD_TEXT_CACHE,
260                 SLOW_INPUT_CONNECTION_ON_FULL_RELOAD_MS,
261                 Constants.EDITOR_CONTENTS_CACHE_SIZE,
262                 0 /* flags */);
263         if (null == textBeforeCursor) {
264             // For some reason the app thinks we are not connected to it. This looks like a
265             // framework bug... Fall back to ground state and return false.
266             mExpectedSelStart = INVALID_CURSOR_POSITION;
267             mExpectedSelEnd = INVALID_CURSOR_POSITION;
268             Log.e(TAG, "Unable to connect to the editor to retrieve text.");
269             return false;
270         }
271         mCommittedTextBeforeComposingText.append(textBeforeCursor);
272         return true;
273     }
274 
checkBatchEdit()275     private void checkBatchEdit() {
276         if (mNestLevel != 1) {
277             // TODO: exception instead
278             Log.e(TAG, "Batch edit level incorrect : " + mNestLevel);
279             Log.e(TAG, DebugLogUtils.getStackTrace(4));
280         }
281     }
282 
finishComposingText()283     public void finishComposingText() {
284         if (DEBUG_BATCH_NESTING) checkBatchEdit();
285         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
286         // TODO: this is not correct! The cursor is not necessarily after the composing text.
287         // In the practice right now this is only called when input ends so it will be reset so
288         // it works, but it's wrong and should be fixed.
289         mCommittedTextBeforeComposingText.append(mComposingText);
290         mComposingText.setLength(0);
291         if (isConnected()) {
292             mIC.finishComposingText();
293         }
294     }
295 
296     /**
297      * Calls {@link InputConnection#commitText(CharSequence, int)}.
298      *
299      * @param text The text to commit. This may include styles.
300      * @param newCursorPosition The new cursor position around the text.
301      */
commitText(final CharSequence text, final int newCursorPosition)302     public void commitText(final CharSequence text, final int newCursorPosition) {
303         if (DEBUG_BATCH_NESTING) checkBatchEdit();
304         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
305         mCommittedTextBeforeComposingText.append(text);
306         // TODO: the following is exceedingly error-prone. Right now when the cursor is in the
307         // middle of the composing word mComposingText only holds the part of the composing text
308         // that is before the cursor, so this actually works, but it's terribly confusing. Fix this.
309         mExpectedSelStart += text.length() - mComposingText.length();
310         mExpectedSelEnd = mExpectedSelStart;
311         mComposingText.setLength(0);
312         if (isConnected()) {
313             mTempObjectForCommitText.clear();
314             mTempObjectForCommitText.append(text);
315             final CharacterStyle[] spans = mTempObjectForCommitText.getSpans(
316                     0, text.length(), CharacterStyle.class);
317             for (final CharacterStyle span : spans) {
318                 final int spanStart = mTempObjectForCommitText.getSpanStart(span);
319                 final int spanEnd = mTempObjectForCommitText.getSpanEnd(span);
320                 final int spanFlags = mTempObjectForCommitText.getSpanFlags(span);
321                 // We have to adjust the end of the span to include an additional character.
322                 // This is to avoid splitting a unicode surrogate pair.
323                 // See com.android.inputmethod.latin.common.Constants.UnicodeSurrogate
324                 // See https://b.corp.google.com/issues/19255233
325                 if (0 < spanEnd && spanEnd < mTempObjectForCommitText.length()) {
326                     final char spanEndChar = mTempObjectForCommitText.charAt(spanEnd - 1);
327                     final char nextChar = mTempObjectForCommitText.charAt(spanEnd);
328                     if (UnicodeSurrogate.isLowSurrogate(spanEndChar)
329                             && UnicodeSurrogate.isHighSurrogate(nextChar)) {
330                         mTempObjectForCommitText.setSpan(span, spanStart, spanEnd + 1, spanFlags);
331                     }
332                 }
333             }
334             mIC.commitText(mTempObjectForCommitText, newCursorPosition);
335         }
336     }
337 
338     @Nullable
getSelectedText(final int flags)339     public CharSequence getSelectedText(final int flags) {
340         return isConnected() ?  mIC.getSelectedText(flags) : null;
341     }
342 
canDeleteCharacters()343     public boolean canDeleteCharacters() {
344         return mExpectedSelStart > 0;
345     }
346 
347     /**
348      * Gets the caps modes we should be in after this specific string.
349      *
350      * This returns a bit set of TextUtils#CAP_MODE_*, masked by the inputType argument.
351      * This method also supports faking an additional space after the string passed in argument,
352      * to support cases where a space will be added automatically, like in phantom space
353      * state for example.
354      * Note that for English, we are using American typography rules (which are not specific to
355      * American English, it's just the most common set of rules for English).
356      *
357      * @param inputType a mask of the caps modes to test for.
358      * @param spacingAndPunctuations the values of the settings to use for locale and separators.
359      * @param hasSpaceBefore if we should consider there should be a space after the string.
360      * @return the caps modes that should be on as a set of bits
361      */
getCursorCapsMode(final int inputType, final SpacingAndPunctuations spacingAndPunctuations, final boolean hasSpaceBefore)362     public int getCursorCapsMode(final int inputType,
363             final SpacingAndPunctuations spacingAndPunctuations, final boolean hasSpaceBefore) {
364         mIC = mParent.getCurrentInputConnection();
365         if (!isConnected()) {
366             return Constants.TextUtils.CAP_MODE_OFF;
367         }
368         if (!TextUtils.isEmpty(mComposingText)) {
369             if (hasSpaceBefore) {
370                 // If we have some composing text and a space before, then we should have
371                 // MODE_CHARACTERS and MODE_WORDS on.
372                 return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS) & inputType;
373             }
374             // We have some composing text - we should be in MODE_CHARACTERS only.
375             return TextUtils.CAP_MODE_CHARACTERS & inputType;
376         }
377         // TODO: this will generally work, but there may be cases where the buffer contains SOME
378         // information but not enough to determine the caps mode accurately. This may happen after
379         // heavy pressing of delete, for example DEFAULT_TEXT_CACHE_SIZE - 5 times or so.
380         // getCapsMode should be updated to be able to return a "not enough info" result so that
381         // we can get more context only when needed.
382         if (TextUtils.isEmpty(mCommittedTextBeforeComposingText) && 0 != mExpectedSelStart) {
383             if (!reloadTextCache()) {
384                 Log.w(TAG, "Unable to connect to the editor. "
385                         + "Setting caps mode without knowing text.");
386             }
387         }
388         // This never calls InputConnection#getCapsMode - in fact, it's a static method that
389         // never blocks or initiates IPC.
390         // TODO: don't call #toString() here. Instead, all accesses to
391         // mCommittedTextBeforeComposingText should be done on the main thread.
392         return CapsModeUtils.getCapsMode(mCommittedTextBeforeComposingText.toString(), inputType,
393                 spacingAndPunctuations, hasSpaceBefore);
394     }
395 
getCodePointBeforeCursor()396     public int getCodePointBeforeCursor() {
397         final int length = mCommittedTextBeforeComposingText.length();
398         if (length < 1) return Constants.NOT_A_CODE;
399         return Character.codePointBefore(mCommittedTextBeforeComposingText, length);
400     }
401 
getTextBeforeCursor(final int n, final int flags)402     public CharSequence getTextBeforeCursor(final int n, final int flags) {
403         final int cachedLength =
404                 mCommittedTextBeforeComposingText.length() + mComposingText.length();
405         // If we have enough characters to satisfy the request, or if we have all characters in
406         // the text field, then we can return the cached version right away.
407         // However, if we don't have an expected cursor position, then we should always
408         // go fetch the cache again (as it happens, INVALID_CURSOR_POSITION < 0, so we need to
409         // test for this explicitly)
410         if (INVALID_CURSOR_POSITION != mExpectedSelStart
411                 && (cachedLength >= n || cachedLength >= mExpectedSelStart)) {
412             final StringBuilder s = new StringBuilder(mCommittedTextBeforeComposingText);
413             // We call #toString() here to create a temporary object.
414             // In some situations, this method is called on a worker thread, and it's possible
415             // the main thread touches the contents of mComposingText while this worker thread
416             // is suspended, because mComposingText is a StringBuilder. This may lead to crashes,
417             // so we call #toString() on it. That will result in the return value being strictly
418             // speaking wrong, but since this is used for basing bigram probability off, and
419             // it's only going to matter for one getSuggestions call, it's fine in the practice.
420             s.append(mComposingText.toString());
421             if (s.length() > n) {
422                 s.delete(0, s.length() - n);
423             }
424             return s;
425         }
426         return getTextBeforeCursorAndDetectLaggyConnection(
427                 OPERATION_GET_TEXT_BEFORE_CURSOR,
428                 SLOW_INPUT_CONNECTION_ON_PARTIAL_RELOAD_MS,
429                 n, flags);
430     }
431 
getTextBeforeCursorAndDetectLaggyConnection( final int operation, final long timeout, final int n, final int flags)432     private CharSequence getTextBeforeCursorAndDetectLaggyConnection(
433             final int operation, final long timeout, final int n, final int flags) {
434         mIC = mParent.getCurrentInputConnection();
435         if (!isConnected()) {
436             return null;
437         }
438         final long startTime = SystemClock.uptimeMillis();
439         final CharSequence result = mIC.getTextBeforeCursor(n, flags);
440         detectLaggyConnection(operation, timeout, startTime);
441         return result;
442     }
443 
getTextAfterCursor(final int n, final int flags)444     public CharSequence getTextAfterCursor(final int n, final int flags) {
445         return getTextAfterCursorAndDetectLaggyConnection(
446                 OPERATION_GET_TEXT_AFTER_CURSOR,
447                 SLOW_INPUT_CONNECTION_ON_PARTIAL_RELOAD_MS,
448                 n, flags);
449     }
450 
getTextAfterCursorAndDetectLaggyConnection( final int operation, final long timeout, final int n, final int flags)451     private CharSequence getTextAfterCursorAndDetectLaggyConnection(
452             final int operation, final long timeout, final int n, final int flags) {
453         mIC = mParent.getCurrentInputConnection();
454         if (!isConnected()) {
455             return null;
456         }
457         final long startTime = SystemClock.uptimeMillis();
458         final CharSequence result = mIC.getTextAfterCursor(n, flags);
459         detectLaggyConnection(operation, timeout, startTime);
460         return result;
461     }
462 
detectLaggyConnection(final int operation, final long timeout, final long startTime)463     private void detectLaggyConnection(final int operation, final long timeout, final long startTime) {
464         final long duration = SystemClock.uptimeMillis() - startTime;
465         if (duration >= timeout) {
466             final String operationName = OPERATION_NAMES[operation];
467             Log.w(TAG, "Slow InputConnection: " + operationName + " took " + duration + " ms.");
468             StatsUtils.onInputConnectionLaggy(operation, duration);
469             mLastSlowInputConnectionTime = SystemClock.uptimeMillis();
470         }
471     }
472 
deleteTextBeforeCursor(final int beforeLength)473     public void deleteTextBeforeCursor(final int beforeLength) {
474         if (DEBUG_BATCH_NESTING) checkBatchEdit();
475         // TODO: the following is incorrect if the cursor is not immediately after the composition.
476         // Right now we never come here in this case because we reset the composing state before we
477         // come here in this case, but we need to fix this.
478         final int remainingChars = mComposingText.length() - beforeLength;
479         if (remainingChars >= 0) {
480             mComposingText.setLength(remainingChars);
481         } else {
482             mComposingText.setLength(0);
483             // Never cut under 0
484             final int len = Math.max(mCommittedTextBeforeComposingText.length()
485                     + remainingChars, 0);
486             mCommittedTextBeforeComposingText.setLength(len);
487         }
488         if (mExpectedSelStart > beforeLength) {
489             mExpectedSelStart -= beforeLength;
490             mExpectedSelEnd -= beforeLength;
491         } else {
492             // There are fewer characters before the cursor in the buffer than we are being asked to
493             // delete. Only delete what is there, and update the end with the amount deleted.
494             mExpectedSelEnd -= mExpectedSelStart;
495             mExpectedSelStart = 0;
496         }
497         if (isConnected()) {
498             mIC.deleteSurroundingText(beforeLength, 0);
499         }
500         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
501     }
502 
performEditorAction(final int actionId)503     public void performEditorAction(final int actionId) {
504         mIC = mParent.getCurrentInputConnection();
505         if (isConnected()) {
506             mIC.performEditorAction(actionId);
507         }
508     }
509 
sendKeyEvent(final KeyEvent keyEvent)510     public void sendKeyEvent(final KeyEvent keyEvent) {
511         if (DEBUG_BATCH_NESTING) checkBatchEdit();
512         if (keyEvent.getAction() == KeyEvent.ACTION_DOWN) {
513             if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
514             // This method is only called for enter or backspace when speaking to old applications
515             // (target SDK <= 15 (Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)), or for digits.
516             // When talking to new applications we never use this method because it's inherently
517             // racy and has unpredictable results, but for backward compatibility we continue
518             // sending the key events for only Enter and Backspace because some applications
519             // mistakenly catch them to do some stuff.
520             switch (keyEvent.getKeyCode()) {
521             case KeyEvent.KEYCODE_ENTER:
522                 mCommittedTextBeforeComposingText.append("\n");
523                 mExpectedSelStart += 1;
524                 mExpectedSelEnd = mExpectedSelStart;
525                 break;
526             case KeyEvent.KEYCODE_DEL:
527                 if (0 == mComposingText.length()) {
528                     if (mCommittedTextBeforeComposingText.length() > 0) {
529                         mCommittedTextBeforeComposingText.delete(
530                                 mCommittedTextBeforeComposingText.length() - 1,
531                                 mCommittedTextBeforeComposingText.length());
532                     }
533                 } else {
534                     mComposingText.delete(mComposingText.length() - 1, mComposingText.length());
535                 }
536                 if (mExpectedSelStart > 0 && mExpectedSelStart == mExpectedSelEnd) {
537                     // TODO: Handle surrogate pairs.
538                     mExpectedSelStart -= 1;
539                 }
540                 mExpectedSelEnd = mExpectedSelStart;
541                 break;
542             case KeyEvent.KEYCODE_UNKNOWN:
543                 if (null != keyEvent.getCharacters()) {
544                     mCommittedTextBeforeComposingText.append(keyEvent.getCharacters());
545                     mExpectedSelStart += keyEvent.getCharacters().length();
546                     mExpectedSelEnd = mExpectedSelStart;
547                 }
548                 break;
549             default:
550                 final String text = StringUtils.newSingleCodePointString(keyEvent.getUnicodeChar());
551                 mCommittedTextBeforeComposingText.append(text);
552                 mExpectedSelStart += text.length();
553                 mExpectedSelEnd = mExpectedSelStart;
554                 break;
555             }
556         }
557         if (isConnected()) {
558             mIC.sendKeyEvent(keyEvent);
559         }
560     }
561 
setComposingRegion(final int start, final int end)562     public void setComposingRegion(final int start, final int end) {
563         if (DEBUG_BATCH_NESTING) checkBatchEdit();
564         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
565         final CharSequence textBeforeCursor =
566                 getTextBeforeCursor(Constants.EDITOR_CONTENTS_CACHE_SIZE + (end - start), 0);
567         mCommittedTextBeforeComposingText.setLength(0);
568         if (!TextUtils.isEmpty(textBeforeCursor)) {
569             // The cursor is not necessarily at the end of the composing text, but we have its
570             // position in mExpectedSelStart and mExpectedSelEnd. In this case we want the start
571             // of the text, so we should use mExpectedSelStart. In other words, the composing
572             // text starts (mExpectedSelStart - start) characters before the end of textBeforeCursor
573             final int indexOfStartOfComposingText =
574                     Math.max(textBeforeCursor.length() - (mExpectedSelStart - start), 0);
575             mComposingText.append(textBeforeCursor.subSequence(indexOfStartOfComposingText,
576                     textBeforeCursor.length()));
577             mCommittedTextBeforeComposingText.append(
578                     textBeforeCursor.subSequence(0, indexOfStartOfComposingText));
579         }
580         if (isConnected()) {
581             mIC.setComposingRegion(start, end);
582         }
583     }
584 
setComposingText(final CharSequence text, final int newCursorPosition)585     public void setComposingText(final CharSequence text, final int newCursorPosition) {
586         if (DEBUG_BATCH_NESTING) checkBatchEdit();
587         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
588         mExpectedSelStart += text.length() - mComposingText.length();
589         mExpectedSelEnd = mExpectedSelStart;
590         mComposingText.setLength(0);
591         mComposingText.append(text);
592         // TODO: support values of newCursorPosition != 1. At this time, this is never called with
593         // newCursorPosition != 1.
594         if (isConnected()) {
595             mIC.setComposingText(text, newCursorPosition);
596         }
597         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
598     }
599 
600     /**
601      * Set the selection of the text editor.
602      *
603      * Calls through to {@link InputConnection#setSelection(int, int)}.
604      *
605      * @param start the character index where the selection should start.
606      * @param end the character index where the selection should end.
607      * @return Returns true on success, false on failure: either the input connection is no longer
608      * valid when setting the selection or when retrieving the text cache at that point, or
609      * invalid arguments were passed.
610      */
setSelection(final int start, final int end)611     public boolean setSelection(final int start, final int end) {
612         if (DEBUG_BATCH_NESTING) checkBatchEdit();
613         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
614         if (start < 0 || end < 0) {
615             return false;
616         }
617         mExpectedSelStart = start;
618         mExpectedSelEnd = end;
619         if (isConnected()) {
620             final boolean isIcValid = mIC.setSelection(start, end);
621             if (!isIcValid) {
622                 return false;
623             }
624         }
625         return reloadTextCache();
626     }
627 
commitCorrection(final CorrectionInfo correctionInfo)628     public void commitCorrection(final CorrectionInfo correctionInfo) {
629         if (DEBUG_BATCH_NESTING) checkBatchEdit();
630         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
631         // This has no effect on the text field and does not change its content. It only makes
632         // TextView flash the text for a second based on indices contained in the argument.
633         if (isConnected()) {
634             mIC.commitCorrection(correctionInfo);
635         }
636         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
637     }
638 
commitCompletion(final CompletionInfo completionInfo)639     public void commitCompletion(final CompletionInfo completionInfo) {
640         if (DEBUG_BATCH_NESTING) checkBatchEdit();
641         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
642         CharSequence text = completionInfo.getText();
643         // text should never be null, but just in case, it's better to insert nothing than to crash
644         if (null == text) text = "";
645         mCommittedTextBeforeComposingText.append(text);
646         mExpectedSelStart += text.length() - mComposingText.length();
647         mExpectedSelEnd = mExpectedSelStart;
648         mComposingText.setLength(0);
649         if (isConnected()) {
650             mIC.commitCompletion(completionInfo);
651         }
652         if (DEBUG_PREVIOUS_TEXT) checkConsistencyForDebug();
653     }
654 
655     @SuppressWarnings("unused")
656     @Nonnull
getNgramContextFromNthPreviousWord( final SpacingAndPunctuations spacingAndPunctuations, final int n)657     public NgramContext getNgramContextFromNthPreviousWord(
658             final SpacingAndPunctuations spacingAndPunctuations, final int n) {
659         mIC = mParent.getCurrentInputConnection();
660         if (!isConnected()) {
661             return NgramContext.EMPTY_PREV_WORDS_INFO;
662         }
663         final CharSequence prev = getTextBeforeCursor(NUM_CHARS_TO_GET_BEFORE_CURSOR, 0);
664         if (DEBUG_PREVIOUS_TEXT && null != prev) {
665             final int checkLength = NUM_CHARS_TO_GET_BEFORE_CURSOR - 1;
666             final String reference = prev.length() <= checkLength ? prev.toString()
667                     : prev.subSequence(prev.length() - checkLength, prev.length()).toString();
668             // TODO: right now the following works because mComposingText holds the part of the
669             // composing text that is before the cursor, but this is very confusing. We should
670             // fix it.
671             final StringBuilder internal = new StringBuilder()
672                     .append(mCommittedTextBeforeComposingText).append(mComposingText);
673             if (internal.length() > checkLength) {
674                 internal.delete(0, internal.length() - checkLength);
675                 if (!(reference.equals(internal.toString()))) {
676                     final String context =
677                             "Expected text = " + internal + "\nActual text = " + reference;
678                     ((LatinIME)mParent).debugDumpStateAndCrashWithException(context);
679                 }
680             }
681         }
682         return NgramContextUtils.getNgramContextFromNthPreviousWord(
683                 prev, spacingAndPunctuations, n);
684     }
685 
isPartOfCompositionForScript(final int codePoint, final SpacingAndPunctuations spacingAndPunctuations, final int scriptId)686     private static boolean isPartOfCompositionForScript(final int codePoint,
687             final SpacingAndPunctuations spacingAndPunctuations, final int scriptId) {
688         // We always consider word connectors part of compositions.
689         return spacingAndPunctuations.isWordConnector(codePoint)
690                 // Otherwise, it's part of composition if it's part of script and not a separator.
691                 || (!spacingAndPunctuations.isWordSeparator(codePoint)
692                         && ScriptUtils.isLetterPartOfScript(codePoint, scriptId));
693     }
694 
695     /**
696      * Returns the text surrounding the cursor.
697      *
698      * @param spacingAndPunctuations the rules for spacing and punctuation
699      * @param scriptId the script we consider to be writing words, as one of ScriptUtils.SCRIPT_*
700      * @return a range containing the text surrounding the cursor
701      */
getWordRangeAtCursor(final SpacingAndPunctuations spacingAndPunctuations, final int scriptId)702     public TextRange getWordRangeAtCursor(final SpacingAndPunctuations spacingAndPunctuations,
703             final int scriptId) {
704         mIC = mParent.getCurrentInputConnection();
705         if (!isConnected()) {
706             return null;
707         }
708         final CharSequence before = getTextBeforeCursorAndDetectLaggyConnection(
709                 OPERATION_GET_WORD_RANGE_AT_CURSOR,
710                 SLOW_INPUT_CONNECTION_ON_PARTIAL_RELOAD_MS,
711                 NUM_CHARS_TO_GET_BEFORE_CURSOR,
712                 InputConnection.GET_TEXT_WITH_STYLES);
713         final CharSequence after = getTextAfterCursorAndDetectLaggyConnection(
714                 OPERATION_GET_WORD_RANGE_AT_CURSOR,
715                 SLOW_INPUT_CONNECTION_ON_PARTIAL_RELOAD_MS,
716                 NUM_CHARS_TO_GET_AFTER_CURSOR,
717                 InputConnection.GET_TEXT_WITH_STYLES);
718         if (before == null || after == null) {
719             return null;
720         }
721 
722         // Going backward, find the first breaking point (separator)
723         int startIndexInBefore = before.length();
724         while (startIndexInBefore > 0) {
725             final int codePoint = Character.codePointBefore(before, startIndexInBefore);
726             if (!isPartOfCompositionForScript(codePoint, spacingAndPunctuations, scriptId)) {
727                 break;
728             }
729             --startIndexInBefore;
730             if (Character.isSupplementaryCodePoint(codePoint)) {
731                 --startIndexInBefore;
732             }
733         }
734 
735         // Find last word separator after the cursor
736         int endIndexInAfter = -1;
737         while (++endIndexInAfter < after.length()) {
738             final int codePoint = Character.codePointAt(after, endIndexInAfter);
739             if (!isPartOfCompositionForScript(codePoint, spacingAndPunctuations, scriptId)) {
740                 break;
741             }
742             if (Character.isSupplementaryCodePoint(codePoint)) {
743                 ++endIndexInAfter;
744             }
745         }
746 
747         final boolean hasUrlSpans =
748                 SpannableStringUtils.hasUrlSpans(before, startIndexInBefore, before.length())
749                 || SpannableStringUtils.hasUrlSpans(after, 0, endIndexInAfter);
750         // We don't use TextUtils#concat because it copies all spans without respect to their
751         // nature. If the text includes a PARAGRAPH span and it has been split, then
752         // TextUtils#concat will crash when it tries to concat both sides of it.
753         return new TextRange(
754                 SpannableStringUtils.concatWithNonParagraphSuggestionSpansOnly(before, after),
755                         startIndexInBefore, before.length() + endIndexInAfter, before.length(),
756                         hasUrlSpans);
757     }
758 
isCursorTouchingWord(final SpacingAndPunctuations spacingAndPunctuations, boolean checkTextAfter)759     public boolean isCursorTouchingWord(final SpacingAndPunctuations spacingAndPunctuations,
760             boolean checkTextAfter) {
761         if (checkTextAfter && isCursorFollowedByWordCharacter(spacingAndPunctuations)) {
762             // If what's after the cursor is a word character, then we're touching a word.
763             return true;
764         }
765         final String textBeforeCursor = mCommittedTextBeforeComposingText.toString();
766         int indexOfCodePointInJavaChars = textBeforeCursor.length();
767         int consideredCodePoint = 0 == indexOfCodePointInJavaChars ? Constants.NOT_A_CODE
768                 : textBeforeCursor.codePointBefore(indexOfCodePointInJavaChars);
769         // Search for the first non word-connector char
770         if (spacingAndPunctuations.isWordConnector(consideredCodePoint)) {
771             indexOfCodePointInJavaChars -= Character.charCount(consideredCodePoint);
772             consideredCodePoint = 0 == indexOfCodePointInJavaChars ? Constants.NOT_A_CODE
773                     : textBeforeCursor.codePointBefore(indexOfCodePointInJavaChars);
774         }
775         return !(Constants.NOT_A_CODE == consideredCodePoint
776                 || spacingAndPunctuations.isWordSeparator(consideredCodePoint)
777                 || spacingAndPunctuations.isWordConnector(consideredCodePoint));
778     }
779 
isCursorFollowedByWordCharacter( final SpacingAndPunctuations spacingAndPunctuations)780     public boolean isCursorFollowedByWordCharacter(
781             final SpacingAndPunctuations spacingAndPunctuations) {
782         final CharSequence after = getTextAfterCursor(1, 0);
783         if (TextUtils.isEmpty(after)) {
784             return false;
785         }
786         final int codePointAfterCursor = Character.codePointAt(after, 0);
787         if (spacingAndPunctuations.isWordSeparator(codePointAfterCursor)
788                 || spacingAndPunctuations.isWordConnector(codePointAfterCursor)) {
789             return false;
790         }
791         return true;
792     }
793 
removeTrailingSpace()794     public void removeTrailingSpace() {
795         if (DEBUG_BATCH_NESTING) checkBatchEdit();
796         final int codePointBeforeCursor = getCodePointBeforeCursor();
797         if (Constants.CODE_SPACE == codePointBeforeCursor) {
798             deleteTextBeforeCursor(1);
799         }
800     }
801 
sameAsTextBeforeCursor(final CharSequence text)802     public boolean sameAsTextBeforeCursor(final CharSequence text) {
803         final CharSequence beforeText = getTextBeforeCursor(text.length(), 0);
804         return TextUtils.equals(text, beforeText);
805     }
806 
revertDoubleSpacePeriod(final SpacingAndPunctuations spacingAndPunctuations)807     public boolean revertDoubleSpacePeriod(final SpacingAndPunctuations spacingAndPunctuations) {
808         if (DEBUG_BATCH_NESTING) checkBatchEdit();
809         // Here we test whether we indeed have a period and a space before us. This should not
810         // be needed, but it's there just in case something went wrong.
811         final CharSequence textBeforeCursor = getTextBeforeCursor(2, 0);
812         if (!TextUtils.equals(spacingAndPunctuations.mSentenceSeparatorAndSpace,
813                 textBeforeCursor)) {
814             // Theoretically we should not be coming here if there isn't ". " before the
815             // cursor, but the application may be changing the text while we are typing, so
816             // anything goes. We should not crash.
817             Log.d(TAG, "Tried to revert double-space combo but we didn't find \""
818                     + spacingAndPunctuations.mSentenceSeparatorAndSpace
819                     + "\" just before the cursor.");
820             return false;
821         }
822         // Double-space results in ". ". A backspace to cancel this should result in a single
823         // space in the text field, so we replace ". " with a single space.
824         deleteTextBeforeCursor(2);
825         final String singleSpace = " ";
826         commitText(singleSpace, 1);
827         return true;
828     }
829 
revertSwapPunctuation()830     public boolean revertSwapPunctuation() {
831         if (DEBUG_BATCH_NESTING) checkBatchEdit();
832         // Here we test whether we indeed have a space and something else before us. This should not
833         // be needed, but it's there just in case something went wrong.
834         final CharSequence textBeforeCursor = getTextBeforeCursor(2, 0);
835         // NOTE: This does not work with surrogate pairs. Hopefully when the keyboard is able to
836         // enter surrogate pairs this code will have been removed.
837         if (TextUtils.isEmpty(textBeforeCursor)
838                 || (Constants.CODE_SPACE != textBeforeCursor.charAt(1))) {
839             // We may only come here if the application is changing the text while we are typing.
840             // This is quite a broken case, but not logically impossible, so we shouldn't crash,
841             // but some debugging log may be in order.
842             Log.d(TAG, "Tried to revert a swap of punctuation but we didn't "
843                     + "find a space just before the cursor.");
844             return false;
845         }
846         deleteTextBeforeCursor(2);
847         final String text = " " + textBeforeCursor.subSequence(0, 1);
848         commitText(text, 1);
849         return true;
850     }
851 
852     /**
853      * Heuristic to determine if this is an expected update of the cursor.
854      *
855      * Sometimes updates to the cursor position are late because of their asynchronous nature.
856      * This method tries to determine if this update is one, based on the values of the cursor
857      * position in the update, and the currently expected position of the cursor according to
858      * LatinIME's internal accounting. If this is not a belated expected update, then it should
859      * mean that the user moved the cursor explicitly.
860      * This is quite robust, but of course it's not perfect. In particular, it will fail in the
861      * case we get an update A, the user types in N characters so as to move the cursor to A+N but
862      * we don't get those, and then the user places the cursor between A and A+N, and we get only
863      * this update and not the ones in-between. This is almost impossible to achieve even trying
864      * very very hard.
865      *
866      * @param oldSelStart The value of the old selection in the update.
867      * @param newSelStart The value of the new selection in the update.
868      * @param oldSelEnd The value of the old selection end in the update.
869      * @param newSelEnd The value of the new selection end in the update.
870      * @return whether this is a belated expected update or not.
871      */
isBelatedExpectedUpdate(final int oldSelStart, final int newSelStart, final int oldSelEnd, final int newSelEnd)872     public boolean isBelatedExpectedUpdate(final int oldSelStart, final int newSelStart,
873             final int oldSelEnd, final int newSelEnd) {
874         // This update is "belated" if we are expecting it. That is, mExpectedSelStart and
875         // mExpectedSelEnd match the new values that the TextView is updating TO.
876         if (mExpectedSelStart == newSelStart && mExpectedSelEnd == newSelEnd) return true;
877         // This update is not belated if mExpectedSelStart and mExpectedSelEnd match the old
878         // values, and one of newSelStart or newSelEnd is updated to a different value. In this
879         // case, it is likely that something other than the IME has moved the selection endpoint
880         // to the new value.
881         if (mExpectedSelStart == oldSelStart && mExpectedSelEnd == oldSelEnd
882                 && (oldSelStart != newSelStart || oldSelEnd != newSelEnd)) return false;
883         // If neither of the above two cases hold, then the system may be having trouble keeping up
884         // with updates. If 1) the selection is a cursor, 2) newSelStart is between oldSelStart
885         // and mExpectedSelStart, and 3) newSelEnd is between oldSelEnd and mExpectedSelEnd, then
886         // assume a belated update.
887         return (newSelStart == newSelEnd)
888                 && (newSelStart - oldSelStart) * (mExpectedSelStart - newSelStart) >= 0
889                 && (newSelEnd - oldSelEnd) * (mExpectedSelEnd - newSelEnd) >= 0;
890     }
891 
892     /**
893      * Looks at the text just before the cursor to find out if it looks like a URL.
894      *
895      * The weakest point here is, if we don't have enough text bufferized, we may fail to realize
896      * we are in URL situation, but other places in this class have the same limitation and it
897      * does not matter too much in the practice.
898      */
textBeforeCursorLooksLikeURL()899     public boolean textBeforeCursorLooksLikeURL() {
900         return StringUtils.lastPartLooksLikeURL(mCommittedTextBeforeComposingText);
901     }
902 
903     /**
904      * Looks at the text just before the cursor to find out if we are inside a double quote.
905      *
906      * As with #textBeforeCursorLooksLikeURL, this is dependent on how much text we have cached.
907      * However this won't be a concrete problem in most situations, as the cache is almost always
908      * long enough for this use.
909      */
isInsideDoubleQuoteOrAfterDigit()910     public boolean isInsideDoubleQuoteOrAfterDigit() {
911         return StringUtils.isInsideDoubleQuoteOrAfterDigit(mCommittedTextBeforeComposingText);
912     }
913 
914     /**
915      * Try to get the text from the editor to expose lies the framework may have been
916      * telling us. Concretely, when the device rotates and when the keyboard reopens in the same
917      * text field after having been closed with the back key, the frameworks tells us about where
918      * the cursor used to be initially in the editor at the time it first received the focus; this
919      * may be completely different from the place it is upon rotation. Since we don't have any
920      * means to get the real value, try at least to ask the text view for some characters and
921      * detect the most damaging cases: when the cursor position is declared to be much smaller
922      * than it really is.
923      */
tryFixLyingCursorPosition()924     public void tryFixLyingCursorPosition() {
925         mIC = mParent.getCurrentInputConnection();
926         final CharSequence textBeforeCursor = getTextBeforeCursor(
927                 Constants.EDITOR_CONTENTS_CACHE_SIZE, 0);
928         final CharSequence selectedText = isConnected() ? mIC.getSelectedText(0 /* flags */) : null;
929         if (null == textBeforeCursor ||
930                 (!TextUtils.isEmpty(selectedText) && mExpectedSelEnd == mExpectedSelStart)) {
931             // If textBeforeCursor is null, we have no idea what kind of text field we have or if
932             // thinking about the "cursor position" actually makes any sense. In this case we
933             // remember a meaningless cursor position. Contrast this with an empty string, which is
934             // valid and should mean the cursor is at the start of the text.
935             // Also, if we expect we don't have a selection but we DO have non-empty selected text,
936             // then the framework lied to us about the cursor position. In this case, we should just
937             // revert to the most basic behavior possible for the next action (backspace in
938             // particular comes to mind), so we remember a meaningless cursor position which should
939             // result in degraded behavior from the next input.
940             // Interestingly, in either case, chances are any action the user takes next will result
941             // in a call to onUpdateSelection, which should set things right.
942             mExpectedSelStart = mExpectedSelEnd = Constants.NOT_A_CURSOR_POSITION;
943         } else {
944             final int textLength = textBeforeCursor.length();
945             if (textLength < Constants.EDITOR_CONTENTS_CACHE_SIZE
946                     && (textLength > mExpectedSelStart
947                             ||  mExpectedSelStart < Constants.EDITOR_CONTENTS_CACHE_SIZE)) {
948                 // It should not be possible to have only one of those variables be
949                 // NOT_A_CURSOR_POSITION, so if they are equal, either the selection is zero-sized
950                 // (simple cursor, no selection) or there is no cursor/we don't know its pos
951                 final boolean wasEqual = mExpectedSelStart == mExpectedSelEnd;
952                 mExpectedSelStart = textLength;
953                 // We can't figure out the value of mLastSelectionEnd :(
954                 // But at least if it's smaller than mLastSelectionStart something is wrong,
955                 // and if they used to be equal we also don't want to make it look like there is a
956                 // selection.
957                 if (wasEqual || mExpectedSelStart > mExpectedSelEnd) {
958                     mExpectedSelEnd = mExpectedSelStart;
959                 }
960             }
961         }
962     }
963 
964     @Override
performPrivateCommand(final String action, final Bundle data)965     public boolean performPrivateCommand(final String action, final Bundle data) {
966         mIC = mParent.getCurrentInputConnection();
967         if (!isConnected()) {
968             return false;
969         }
970         return mIC.performPrivateCommand(action, data);
971     }
972 
getExpectedSelectionStart()973     public int getExpectedSelectionStart() {
974         return mExpectedSelStart;
975     }
976 
getExpectedSelectionEnd()977     public int getExpectedSelectionEnd() {
978         return mExpectedSelEnd;
979     }
980 
981     /**
982      * @return whether there is a selection currently active.
983      */
hasSelection()984     public boolean hasSelection() {
985         return mExpectedSelEnd != mExpectedSelStart;
986     }
987 
isCursorPositionKnown()988     public boolean isCursorPositionKnown() {
989         return INVALID_CURSOR_POSITION != mExpectedSelStart;
990     }
991 
992     /**
993      * Work around a bug that was present before Jelly Bean upon rotation.
994      *
995      * Before Jelly Bean, there is a bug where setComposingRegion and other committing
996      * functions on the input connection get ignored until the cursor moves. This method works
997      * around the bug by wiggling the cursor first, which reactivates the connection and has
998      * the subsequent methods work, then restoring it to its original position.
999      *
1000      * On platforms on which this method is not present, this is a no-op.
1001      */
maybeMoveTheCursorAroundAndRestoreToWorkaroundABug()1002     public void maybeMoveTheCursorAroundAndRestoreToWorkaroundABug() {
1003         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
1004             if (mExpectedSelStart > 0) {
1005                 mIC.setSelection(mExpectedSelStart - 1, mExpectedSelStart - 1);
1006             } else {
1007                 mIC.setSelection(mExpectedSelStart + 1, mExpectedSelStart + 1);
1008             }
1009             mIC.setSelection(mExpectedSelStart, mExpectedSelEnd);
1010         }
1011     }
1012 
1013     /**
1014      * Requests the editor to call back {@link InputMethodManager#updateCursorAnchorInfo}.
1015      * @param enableMonitor {@code true} to request the editor to call back the method whenever the
1016      * cursor/anchor position is changed.
1017      * @param requestImmediateCallback {@code true} to request the editor to call back the method
1018      * as soon as possible to notify the current cursor/anchor position to the input method.
1019      * @return {@code true} if the request is accepted. Returns {@code false} otherwise, which
1020      * includes "not implemented" or "rejected" or "temporarily unavailable" or whatever which
1021      * prevents the application from fulfilling the request. (TODO: Improve the API when it turns
1022      * out that we actually need more detailed error codes)
1023      */
requestCursorUpdates(final boolean enableMonitor, final boolean requestImmediateCallback)1024     public boolean requestCursorUpdates(final boolean enableMonitor,
1025             final boolean requestImmediateCallback) {
1026         mIC = mParent.getCurrentInputConnection();
1027         if (!isConnected()) {
1028             return false;
1029         }
1030         return InputConnectionCompatUtils.requestCursorUpdates(
1031                 mIC, enableMonitor, requestImmediateCallback);
1032     }
1033 }
1034