/*
* Copyright (C) 2011 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 android.widget;
import android.content.Context;
import android.text.Editable;
import android.text.Selection;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.method.WordIterator;
import android.text.style.SpellCheckSpan;
import android.text.style.SuggestionSpan;
import android.view.textservice.SpellCheckerSession;
import android.view.textservice.SpellCheckerSession.SpellCheckerSessionListener;
import android.view.textservice.SuggestionsInfo;
import android.view.textservice.TextInfo;
import android.view.textservice.TextServicesManager;
import com.android.internal.util.ArrayUtils;
import java.text.BreakIterator;
import java.util.Locale;
/**
* Helper class for TextView. Bridge between the TextView and the Dictionnary service.
*
* @hide
*/
public class SpellChecker implements SpellCheckerSessionListener {
// No more than this number of words will be parsed on each iteration to ensure a minimum
// lock of the UI thread
public static final int MAX_NUMBER_OF_WORDS = 50;
// Rough estimate, such that the word iterator interval usually does not need to be shifted
public static final int AVERAGE_WORD_LENGTH = 7;
// When parsing, use a character window of that size. Will be shifted if needed
public static final int WORD_ITERATOR_INTERVAL = AVERAGE_WORD_LENGTH * MAX_NUMBER_OF_WORDS;
// Pause between each spell check to keep the UI smooth
private final static int SPELL_PAUSE_DURATION = 400; // milliseconds
private final TextView mTextView;
SpellCheckerSession mSpellCheckerSession;
final int mCookie;
// Paired arrays for the (id, spellCheckSpan) pair. A negative id means the associated
// SpellCheckSpan has been recycled and can be-reused.
// Contains null SpellCheckSpans after index mLength.
private int[] mIds;
private SpellCheckSpan[] mSpellCheckSpans;
// The mLength first elements of the above arrays have been initialized
private int mLength;
// Parsers on chunck of text, cutting text into words that will be checked
private SpellParser[] mSpellParsers = new SpellParser[0];
private int mSpanSequenceCounter = 0;
private Locale mCurrentLocale;
// Shared by all SpellParsers. Cannot be shared with TextView since it may be used
// concurrently due to the asynchronous nature of onGetSuggestions.
private WordIterator mWordIterator;
private TextServicesManager mTextServicesManager;
private Runnable mSpellRunnable;
public SpellChecker(TextView textView) {
mTextView = textView;
// Arbitrary: these arrays will automatically double their sizes on demand
final int size = ArrayUtils.idealObjectArraySize(1);
mIds = new int[size];
mSpellCheckSpans = new SpellCheckSpan[size];
setLocale(mTextView.getTextServicesLocale());
mCookie = hashCode();
}
private void resetSession() {
closeSession();
mTextServicesManager = (TextServicesManager) mTextView.getContext().
getSystemService(Context.TEXT_SERVICES_MANAGER_SERVICE);
if (!mTextServicesManager.isSpellCheckerEnabled()) {
mSpellCheckerSession = null;
} else {
mSpellCheckerSession = mTextServicesManager.newSpellCheckerSession(
null /* Bundle not currently used by the textServicesManager */,
mCurrentLocale, this,
false /* means any available languages from current spell checker */);
}
// Restore SpellCheckSpans in pool
for (int i = 0; i < mLength; i++) {
mSpellCheckSpans[i].setSpellCheckInProgress(false);
mIds[i] = -1;
}
mLength = 0;
// Remove existing misspelled SuggestionSpans
mTextView.removeMisspelledSpans((Editable) mTextView.getText());
// This class is the listener for locale change: warn other locale-aware objects
mTextView.onLocaleChanged();
}
private void setLocale(Locale locale) {
mCurrentLocale = locale;
resetSession();
// Change SpellParsers' wordIterator locale
mWordIterator = new WordIterator(locale);
// This class is the listener for locale change: warn other locale-aware objects
mTextView.onLocaleChanged();
}
/**
* @return true if a spell checker session has successfully been created. Returns false if not,
* for instance when spell checking has been disabled in settings.
*/
private boolean isSessionActive() {
return mSpellCheckerSession != null;
}
public void closeSession() {
if (mSpellCheckerSession != null) {
mSpellCheckerSession.close();
}
final int length = mSpellParsers.length;
for (int i = 0; i < length; i++) {
mSpellParsers[i].finish();
}
if (mSpellRunnable != null) {
mTextView.removeCallbacks(mSpellRunnable);
}
}
private int nextSpellCheckSpanIndex() {
for (int i = 0; i < mLength; i++) {
if (mIds[i] < 0) return i;
}
if (mLength == mSpellCheckSpans.length) {
final int newSize = mLength * 2;
int[] newIds = new int[newSize];
SpellCheckSpan[] newSpellCheckSpans = new SpellCheckSpan[newSize];
System.arraycopy(mIds, 0, newIds, 0, mLength);
System.arraycopy(mSpellCheckSpans, 0, newSpellCheckSpans, 0, mLength);
mIds = newIds;
mSpellCheckSpans = newSpellCheckSpans;
}
mSpellCheckSpans[mLength] = new SpellCheckSpan();
mLength++;
return mLength - 1;
}
private void addSpellCheckSpan(Editable editable, int start, int end) {
final int index = nextSpellCheckSpanIndex();
editable.setSpan(mSpellCheckSpans[index], start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
mIds[index] = mSpanSequenceCounter++;
}
public void removeSpellCheckSpan(SpellCheckSpan spellCheckSpan) {
for (int i = 0; i < mLength; i++) {
if (mSpellCheckSpans[i] == spellCheckSpan) {
mSpellCheckSpans[i].setSpellCheckInProgress(false);
mIds[i] = -1;
return;
}
}
}
public void onSelectionChanged() {
spellCheck();
}
public void spellCheck(int start, int end) {
final Locale locale = mTextView.getTextServicesLocale();
if (mCurrentLocale == null || (!(mCurrentLocale.equals(locale)))) {
setLocale(locale);
// Re-check the entire text
start = 0;
end = mTextView.getText().length();
} else {
final boolean spellCheckerActivated = mTextServicesManager.isSpellCheckerEnabled();
if (isSessionActive() != spellCheckerActivated) {
// Spell checker has been turned of or off since last spellCheck
resetSession();
}
}
if (!isSessionActive()) return;
final int length = mSpellParsers.length;
for (int i = 0; i < length; i++) {
final SpellParser spellParser = mSpellParsers[i];
if (spellParser.isFinished()) {
spellParser.init(start, end);
spellParser.parse();
return;
}
}
// No available parser found in pool, create a new one
SpellParser[] newSpellParsers = new SpellParser[length + 1];
System.arraycopy(mSpellParsers, 0, newSpellParsers, 0, length);
mSpellParsers = newSpellParsers;
SpellParser spellParser = new SpellParser();
mSpellParsers[length] = spellParser;
spellParser.init(start, end);
spellParser.parse();
}
private void spellCheck() {
if (mSpellCheckerSession == null) return;
Editable editable = (Editable) mTextView.getText();
final int selectionStart = Selection.getSelectionStart(editable);
final int selectionEnd = Selection.getSelectionEnd(editable);
TextInfo[] textInfos = new TextInfo[mLength];
int textInfosCount = 0;
for (int i = 0; i < mLength; i++) {
final SpellCheckSpan spellCheckSpan = mSpellCheckSpans[i];
if (spellCheckSpan.isSpellCheckInProgress()) continue;
final int start = editable.getSpanStart(spellCheckSpan);
final int end = editable.getSpanEnd(spellCheckSpan);
// Do not check this word if the user is currently editing it
if (start >= 0 && end > start && (selectionEnd < start || selectionStart > end)) {
final String word = (editable instanceof SpannableStringBuilder) ?
((SpannableStringBuilder) editable).substring(start, end) :
editable.subSequence(start, end).toString();
spellCheckSpan.setSpellCheckInProgress(true);
textInfos[textInfosCount++] = new TextInfo(word, mCookie, mIds[i]);
}
}
if (textInfosCount > 0) {
if (textInfosCount < textInfos.length) {
TextInfo[] textInfosCopy = new TextInfo[textInfosCount];
System.arraycopy(textInfos, 0, textInfosCopy, 0, textInfosCount);
textInfos = textInfosCopy;
}
mSpellCheckerSession.getSuggestions(textInfos, SuggestionSpan.SUGGESTIONS_MAX_SIZE,
false /* TODO Set sequentialWords to true for initial spell check */);
}
}
@Override
public void onGetSuggestions(SuggestionsInfo[] results) {
Editable editable = (Editable) mTextView.getText();
for (int i = 0; i < results.length; i++) {
SuggestionsInfo suggestionsInfo = results[i];
if (suggestionsInfo.getCookie() != mCookie) continue;
final int sequenceNumber = suggestionsInfo.getSequence();
for (int j = 0; j < mLength; j++) {
if (sequenceNumber == mIds[j]) {
final int attributes = suggestionsInfo.getSuggestionsAttributes();
boolean isInDictionary =
((attributes & SuggestionsInfo.RESULT_ATTR_IN_THE_DICTIONARY) > 0);
boolean looksLikeTypo =
((attributes & SuggestionsInfo.RESULT_ATTR_LOOKS_LIKE_TYPO) > 0);
SpellCheckSpan spellCheckSpan = mSpellCheckSpans[j];
if (!isInDictionary && looksLikeTypo) {
createMisspelledSuggestionSpan(editable, suggestionsInfo, spellCheckSpan);
}
editable.removeSpan(spellCheckSpan);
break;
}
}
}
scheduleNewSpellCheck();
}
private void scheduleNewSpellCheck() {
if (mSpellRunnable == null) {
mSpellRunnable = new Runnable() {
@Override
public void run() {
final int length = mSpellParsers.length;
for (int i = 0; i < length; i++) {
final SpellParser spellParser = mSpellParsers[i];
if (!spellParser.isFinished()) {
spellParser.parse();
break; // run one spell parser at a time to bound running time
}
}
}
};
} else {
mTextView.removeCallbacks(mSpellRunnable);
}
mTextView.postDelayed(mSpellRunnable, SPELL_PAUSE_DURATION);
}
private void createMisspelledSuggestionSpan(Editable editable, SuggestionsInfo suggestionsInfo,
SpellCheckSpan spellCheckSpan) {
final int start = editable.getSpanStart(spellCheckSpan);
final int end = editable.getSpanEnd(spellCheckSpan);
if (start < 0 || end <= start) return; // span was removed in the meantime
// Other suggestion spans may exist on that region, with identical suggestions, filter
// them out to avoid duplicates.
SuggestionSpan[] suggestionSpans = editable.getSpans(start, end, SuggestionSpan.class);
final int length = suggestionSpans.length;
for (int i = 0; i < length; i++) {
final int spanStart = editable.getSpanStart(suggestionSpans[i]);
final int spanEnd = editable.getSpanEnd(suggestionSpans[i]);
if (spanStart != start || spanEnd != end) {
// Nulled (to avoid new array allocation) if not on that exact same region
suggestionSpans[i] = null;
}
}
final int suggestionsCount = suggestionsInfo.getSuggestionsCount();
String[] suggestions;
if (suggestionsCount <= 0) {
// A negative suggestion count is possible
suggestions = ArrayUtils.emptyArray(String.class);
} else {
int numberOfSuggestions = 0;
suggestions = new String[suggestionsCount];
for (int i = 0; i < suggestionsCount; i++) {
final String spellSuggestion = suggestionsInfo.getSuggestionAt(i);
if (spellSuggestion == null) break;
boolean suggestionFound = false;
for (int j = 0; j < length && !suggestionFound; j++) {
if (suggestionSpans[j] == null) break;
String[] suggests = suggestionSpans[j].getSuggestions();
for (int k = 0; k < suggests.length; k++) {
if (spellSuggestion.equals(suggests[k])) {
// The suggestion is already provided by an other SuggestionSpan
suggestionFound = true;
break;
}
}
}
if (!suggestionFound) {
suggestions[numberOfSuggestions++] = spellSuggestion;
}
}
if (numberOfSuggestions != suggestionsCount) {
String[] newSuggestions = new String[numberOfSuggestions];
System.arraycopy(suggestions, 0, newSuggestions, 0, numberOfSuggestions);
suggestions = newSuggestions;
}
}
SuggestionSpan suggestionSpan = new SuggestionSpan(mTextView.getContext(), suggestions,
SuggestionSpan.FLAG_EASY_CORRECT | SuggestionSpan.FLAG_MISSPELLED);
editable.setSpan(suggestionSpan, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
mTextView.invalidateRegion(start, end, false /* No cursor involved */);
}
private class SpellParser {
private Object mRange = new Object();
public void init(int start, int end) {
((Editable) mTextView.getText()).setSpan(mRange, start, end,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
public void finish() {
((Editable) mTextView.getText()).removeSpan(mRange);
}
public boolean isFinished() {
return ((Editable) mTextView.getText()).getSpanStart(mRange) < 0;
}
public void parse() {
Editable editable = (Editable) mTextView.getText();
// Iterate over the newly added text and schedule new SpellCheckSpans
final int start = editable.getSpanStart(mRange);
final int end = editable.getSpanEnd(mRange);
int wordIteratorWindowEnd = Math.min(end, start + WORD_ITERATOR_INTERVAL);
mWordIterator.setCharSequence(editable, start, wordIteratorWindowEnd);
// Move back to the beginning of the current word, if any
int wordStart = mWordIterator.preceding(start);
int wordEnd;
if (wordStart == BreakIterator.DONE) {
wordEnd = mWordIterator.following(start);
if (wordEnd != BreakIterator.DONE) {
wordStart = mWordIterator.getBeginning(wordEnd);
}
} else {
wordEnd = mWordIterator.getEnd(wordStart);
}
if (wordEnd == BreakIterator.DONE) {
editable.removeSpan(mRange);
return;
}
// We need to expand by one character because we want to include the spans that
// end/start at position start/end respectively.
SpellCheckSpan[] spellCheckSpans = editable.getSpans(start - 1, end + 1,
SpellCheckSpan.class);
SuggestionSpan[] suggestionSpans = editable.getSpans(start - 1, end + 1,
SuggestionSpan.class);
int wordCount = 0;
boolean scheduleOtherSpellCheck = false;
while (wordStart <= end) {
if (wordEnd >= start && wordEnd > wordStart) {
if (wordCount >= MAX_NUMBER_OF_WORDS) {
scheduleOtherSpellCheck = true;
break;
}
// A new word has been created across the interval boundaries with this edit.
// Previous spans (ended on start / started on end) removed, not valid anymore
if (wordStart < start && wordEnd > start) {
removeSpansAt(editable, start, spellCheckSpans);
removeSpansAt(editable, start, suggestionSpans);
}
if (wordStart < end && wordEnd > end) {
removeSpansAt(editable, end, spellCheckSpans);
removeSpansAt(editable, end, suggestionSpans);
}
// Do not create new boundary spans if they already exist
boolean createSpellCheckSpan = true;
if (wordEnd == start) {
for (int i = 0; i < spellCheckSpans.length; i++) {
final int spanEnd = editable.getSpanEnd(spellCheckSpans[i]);
if (spanEnd == start) {
createSpellCheckSpan = false;
break;
}
}
}
if (wordStart == end) {
for (int i = 0; i < spellCheckSpans.length; i++) {
final int spanStart = editable.getSpanStart(spellCheckSpans[i]);
if (spanStart == end) {
createSpellCheckSpan = false;
break;
}
}
}
if (createSpellCheckSpan) {
addSpellCheckSpan(editable, wordStart, wordEnd);
}
wordCount++;
}
// iterate word by word
int originalWordEnd = wordEnd;
wordEnd = mWordIterator.following(wordEnd);
if ((wordIteratorWindowEnd < end) &&
(wordEnd == BreakIterator.DONE || wordEnd >= wordIteratorWindowEnd)) {
wordIteratorWindowEnd = Math.min(end, originalWordEnd + WORD_ITERATOR_INTERVAL);
mWordIterator.setCharSequence(editable, originalWordEnd, wordIteratorWindowEnd);
wordEnd = mWordIterator.following(originalWordEnd);
}
if (wordEnd == BreakIterator.DONE) break;
wordStart = mWordIterator.getBeginning(wordEnd);
if (wordStart == BreakIterator.DONE) {
break;
}
}
if (scheduleOtherSpellCheck) {
editable.setSpan(mRange, wordStart, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
} else {
editable.removeSpan(mRange);
}
spellCheck();
}
private <T> void removeSpansAt(Editable editable, int offset, T[] spans) {
final int length = spans.length;
for (int i = 0; i < length; i++) {
final T span = spans[i];
final int start = editable.getSpanStart(span);
if (start > offset) continue;
final int end = editable.getSpanEnd(span);
if (end < offset) continue;
editable.removeSpan(span);
}
}
}
}