URLSpanCache.kt

/*
 * Copyright 2023 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.compose.ui.text.platform

import android.text.style.URLSpan
import androidx.compose.ui.text.ExperimentalTextApi
import androidx.compose.ui.text.InternalTextApi
import androidx.compose.ui.text.UrlAnnotation
import java.util.WeakHashMap

/**
 * This class converts [UrlAnnotation]s to [URLSpan]s, ensuring that the same instance of [URLSpan]
 * will be returned for every instance of [UrlAnnotation]. This is required for [URLSpan]s (and
 * any ClickableSpan) to be handled correctly by accessibility services, which require every
 * ClickableSpan to have a stable ID across reads from the accessibility node. A11y services convert
 * these spans to parcelable ones, then look them up later using their ID. Since the ID is a hidden
 * property, the only way to satisfy this constraint is to actually use the same [URLSpan] instance
 * every time.
 *
 * See b/253292081.
 */
// "URL" violates naming guidelines, but that is intentional to match the platform API.
@Suppress("AcronymName")
@OptIn(ExperimentalTextApi::class)
@InternalTextApi
class URLSpanCache {
    private val spansByAnnotation = WeakHashMap<UrlAnnotation, URLSpan>()

    @Suppress("AcronymName")
    fun toURLSpan(urlAnnotation: UrlAnnotation): URLSpan =
        spansByAnnotation.getOrPut(urlAnnotation) { URLSpan(urlAnnotation.url) }
}