UnprecomputeTextOnModificationSpannable.java
/*
* Copyright 2022 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 androidx.emoji2.text;
import android.os.Build;
import android.text.PrecomputedText;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.Spanned;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.core.text.PrecomputedTextCompat;
import java.util.stream.IntStream;
/**
* Spannable that will delegate to a passed spannable for all query operations without allocation.
*
* If delegating to a PrecomputedText, the delegate will be swapped for a SpannableString prior
* to any modifications.
*/
class UnprecomputeTextOnModificationSpannable implements Spannable {
/**
* True when mDelegate is safe to write, otherwise mDelegate will need wrapped before mutation
*/
private boolean mSafeToWrite = false;
@NonNull
private Spannable mDelegate;
UnprecomputeTextOnModificationSpannable(@NonNull Spannable delegate) {
mDelegate = delegate;
}
UnprecomputeTextOnModificationSpannable(@NonNull Spanned delegate) {
mDelegate = new SpannableString(delegate);
}
UnprecomputeTextOnModificationSpannable(@NonNull CharSequence delegate) {
mDelegate = new SpannableString(delegate);
}
private void ensureSafeWrites() {
Spannable old = mDelegate;
if (!mSafeToWrite && precomputedTextDetector().isPrecomputedText(old)) {
mDelegate = new SpannableString(old);
}
mSafeToWrite = true;
}
Spannable getUnwrappedSpannable() {
return mDelegate;
}
@Override
public void setSpan(Object o, int i, int i1, int i2) {
ensureSafeWrites();
mDelegate.setSpan(o, i, i1, i2);
}
@Override
public void removeSpan(Object o) {
ensureSafeWrites();
mDelegate.removeSpan(o);
}
@Override
public <T> T[] getSpans(int i, int i1, Class<T> aClass) {
return mDelegate.getSpans(i, i1, aClass);
}
@Override
public int getSpanStart(Object o) {
return mDelegate.getSpanStart(o);
}
@Override
public int getSpanEnd(Object o) {
return mDelegate.getSpanEnd(o);
}
@Override
public int getSpanFlags(Object o) {
return mDelegate.getSpanFlags(o);
}
@Override
public int nextSpanTransition(int i, int i1, Class aClass) {
return mDelegate.nextSpanTransition(i, i1, aClass);
}
@Override
public int length() {
return mDelegate.length();
}
@Override
public char charAt(int i) {
return mDelegate.charAt(i);
}
@NonNull
@Override
public CharSequence subSequence(int i, int i1) {
return mDelegate.subSequence(i, i1);
}
@NonNull
@Override
public String toString() {
return mDelegate.toString();
}
@RequiresApi(api = Build.VERSION_CODES.N)
@NonNull
@Override
public IntStream chars() {
return CharSequenceHelper_API24.chars(mDelegate);
}
@RequiresApi(api = Build.VERSION_CODES.N)
@NonNull
@Override
public IntStream codePoints() {
return CharSequenceHelper_API24.codePoints(mDelegate);
}
@RequiresApi(24)
private static class CharSequenceHelper_API24 {
private CharSequenceHelper_API24() {
// not constructable
}
static IntStream codePoints(CharSequence charSequence) {
return charSequence.codePoints();
}
static IntStream chars(CharSequence charSequence) {
return charSequence.chars();
}
}
static PrecomputedTextDetector precomputedTextDetector() {
return (Build.VERSION.SDK_INT < Build.VERSION_CODES.P)
? new PrecomputedTextDetector() : new PrecomputedTextDetector_28();
}
static class PrecomputedTextDetector {
boolean isPrecomputedText(CharSequence text) {
return text instanceof PrecomputedTextCompat;
}
}
@RequiresApi(28)
static class PrecomputedTextDetector_28 extends PrecomputedTextDetector {
@Override
boolean isPrecomputedText(CharSequence text) {
return text instanceof PrecomputedText || text instanceof PrecomputedTextCompat;
}
}
}