ContextCompatHelper.kt

/*
 * 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.window.layout.util

import android.app.Activity
import android.content.Context
import android.content.ContextWrapper
import android.graphics.Rect
import android.inputmethodservice.InputMethodService
import android.os.Build
import android.view.WindowManager
import androidx.annotation.DoNotInline
import androidx.annotation.RequiresApi
import androidx.annotation.UiContext
import androidx.core.view.WindowInsetsCompat
import androidx.window.layout.WindowMetrics

internal object ContextCompatHelper {
    /**
     * Given a [UiContext], check if it is a [ContextWrapper]. If so, we need to unwrap it and
     * return the actual [UiContext] within.
     */
    @UiContext
    internal fun unwrapUiContext(@UiContext context: Context): Context {
        var iterator = context

        while (iterator is ContextWrapper) {
            if (iterator is Activity) {
                // Activities are always ContextWrappers
                return iterator
            } else if (iterator is InputMethodService) {
                // InputMethodService are always ContextWrappers
                return iterator
            } else if (iterator.baseContext == null) {
                return iterator
            }

            iterator = iterator.baseContext
        }

        // TODO(b/259148796): This code path is not needed for APIs R and above. However, that is
        //  not clear and also not enforced anywhere. Once we move to version-based implementations,
        //  this ambiguity will no longer exist. Again for clarity, on APIs before R, UiContexts are
        //  Activities or InputMethodServices, so we should never reach this point.
        throw IllegalArgumentException("Context $context is not a UiContext")
    }
}

@RequiresApi(Build.VERSION_CODES.N)
internal object ContextCompatHelperApi24 {
    fun isInMultiWindowMode(activity: Activity): Boolean {
        return activity.isInMultiWindowMode
    }
}

@RequiresApi(Build.VERSION_CODES.R)
internal object ContextCompatHelperApi30 {

    fun currentWindowMetrics(@UiContext context: Context): WindowMetrics {
        val wm = context.getSystemService(WindowManager::class.java)
        val insets = WindowInsetsCompat.toWindowInsetsCompat(wm.currentWindowMetrics.windowInsets)
        return WindowMetrics(wm.currentWindowMetrics.bounds, insets)
    }

    fun currentWindowBounds(@UiContext context: Context): Rect {
        val wm = context.getSystemService(WindowManager::class.java)
        return wm.currentWindowMetrics.bounds
    }

    fun maximumWindowBounds(@UiContext context: Context): Rect {
        val wm = context.getSystemService(WindowManager::class.java)
        return wm.maximumWindowMetrics.bounds
    }

    /**
     * Computes the [WindowInsetsCompat] for platforms above [Build.VERSION_CODES.R], inclusive.
     * @DoNotInline required for implementation-specific class method to prevent it from being
     * inlined.
     *
     * @see androidx.window.layout.WindowMetrics.getWindowInsets
     */
    @DoNotInline
    fun currentWindowInsets(@UiContext context: Context): WindowInsetsCompat {
        val platformInsets = context.getSystemService(WindowManager::class.java)
            .currentWindowMetrics.windowInsets
        return WindowInsetsCompat.toWindowInsetsCompat(platformInsets)
    }
}