| /* |
| * Copyright 2019 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.ui.tooling.preview |
| |
| import android.util.Log |
| import androidx.compose.Composer |
| import java.lang.reflect.Method |
| import java.lang.reflect.Modifier |
| import kotlin.math.ceil |
| import kotlin.reflect.KClass |
| import kotlin.reflect.KParameter |
| import kotlin.reflect.jvm.isAccessible |
| |
| /** |
| * Returns true if the [methodTypes] and [actualTypes] are compatible. This means that every |
| * `actualTypes[n]` are assignable to `methodTypes[n]`. |
| */ |
| private fun compatibleTypes(methodTypes: Array<Class<*>>, actualTypes: Array<Class<*>>): Boolean = |
| methodTypes.size == actualTypes.size && |
| methodTypes.mapIndexed { index, clazz -> clazz.isAssignableFrom(actualTypes[index]) } |
| .all { it } |
| |
| /** |
| * Same as [Class#getDeclaredMethod] but it accounts for compatible types so the signature does |
| * not need to exactly match. This allows finding method calls that use subclasses as parameters |
| * instead of the exact types. |
| */ |
| private fun Class<*>.getDeclaredCompatibleMethod(methodName: String, vararg args: Class<*>): |
| Method { |
| val actualTypes: Array<Class<*>> = arrayOf(*args) |
| return declaredMethods.firstOrNull { |
| methodName == it.name && compatibleTypes(it.parameterTypes, actualTypes) |
| } ?: throw NoSuchMethodException("$methodName not found") |
| } |
| |
| private inline fun <reified T> T.dup(count: Int): Array<T> { |
| return (0..count).map { this }.toTypedArray() |
| } |
| |
| /** |
| * Find the given method by name. If the method has parameters, this function will try to find |
| * the version that accepts default parameters. |
| */ |
| private fun Class<*>.findComposableMethod(methodName: String, vararg args: Any?): Method { |
| val method = try { |
| // without defaults |
| val changedParams = changedParamCount(args.size, 0) |
| getDeclaredCompatibleMethod( |
| methodName, |
| *args.mapNotNull { it?.javaClass }.toTypedArray(), |
| Composer::class.java, // composer param |
| Int::class.java, // key param |
| *Int::class.java.dup(changedParams) // changed params |
| ) |
| } catch (e: ReflectiveOperationException) { |
| try { |
| declaredMethods.find { it.name == methodName } |
| } catch (e: ReflectiveOperationException) { |
| null |
| } |
| } ?: throw NoSuchMethodException("$name.$methodName") |
| |
| return method |
| } |
| |
| /** |
| * Returns the default value for the [Class] type. This will be 0 for numeric types, false for |
| * boolean, '0' for char and null for object references. |
| */ |
| private fun Class<*>.getDefaultValue(): Any? = when (name) { |
| "int" -> 0.toInt() |
| "short" -> 0.toShort() |
| "byte" -> 0.toByte() |
| "long" -> 0.toLong() |
| "double" -> 0.toDouble() |
| "float" -> 0.toFloat() |
| "boolean" -> false |
| "char" -> '0' |
| else -> null |
| } |
| |
| /** |
| * Calls the method on the given [instance]. If the method accepts default values, this function |
| * will call it with the correct options set. |
| */ |
| private fun Method.invokeComposableMethod( |
| instance: Any?, |
| composer: Composer<*>, |
| vararg args: Any? |
| ): Any? { |
| val composerIndex = parameterTypes.indexOfLast { it == Composer::class.java } |
| val realParams = composerIndex |
| val thisParams = if (instance != null) 1 else 0 |
| val changedParams = changedParamCount(realParams, thisParams) |
| val totalParamsWithoutDefaults = realParams + |
| 1 + // composer |
| 1 + // key |
| changedParams |
| val totalParams = parameterTypes.size |
| val isDefault = totalParams != totalParamsWithoutDefaults |
| val defaultParams = if (isDefault) |
| defaultParamCount(realParams) |
| else |
| 0 |
| |
| check( |
| realParams + |
| 1 + // composer |
| 1 + // key |
| changedParams + |
| defaultParams == |
| totalParams |
| ) |
| |
| val keyIndex = composerIndex + 1 |
| val changedStartIndex = keyIndex + 1 |
| val defaultStartIndex = changedStartIndex + changedParams |
| |
| val arguments = Array(totalParams) { idx -> |
| when (idx) { |
| // pass in "empty" value for all real parameters since we will be using defaults. |
| in 0 until realParams -> args.getOrElse(idx) { parameterTypes[idx].getDefaultValue() } |
| // the composer is the first synthetic parameter |
| composerIndex -> composer |
| // since this is the root we don't need to be anything unique. 0 should suffice. |
| keyIndex -> 0 |
| // changed parameters should be 0 to indicate "uncertain" |
| in changedStartIndex until defaultStartIndex -> 0 |
| // Default values mask, all parameters set to use defaults |
| in defaultStartIndex until totalParams -> 0b111111111111111111111.toInt() |
| else -> error("Unexpected index") |
| } |
| } |
| return invoke(instance, *arguments) |
| } |
| |
| private const val SLOTS_PER_INT = 15 |
| private const val BITS_PER_INT = 31 |
| |
| private fun changedParamCount(realValueParams: Int, thisParams: Int): Int { |
| if (realValueParams == 0) return 1 |
| val totalParams = realValueParams + thisParams |
| return ceil( |
| totalParams.toDouble() / SLOTS_PER_INT.toDouble() |
| ).toInt() |
| } |
| |
| private fun defaultParamCount(realValueParams: Int): Int { |
| return ceil( |
| realValueParams.toDouble() / BITS_PER_INT.toDouble() |
| ).toInt() |
| } |
| |
| /** |
| * Invokes the given [methodName] belonging to the given [className] via reflection. The |
| * [methodName] is expected to be a Composable function. |
| * This method [args] will be forwarded to the Composable function. |
| */ |
| internal fun invokeComposableViaReflection( |
| className: String, |
| methodName: String, |
| composer: Composer<*>, |
| vararg args: Any? |
| ) { |
| try { |
| val composableClass = Class.forName(className) |
| |
| val method = composableClass.findComposableMethod(methodName, *args) |
| method.isAccessible = true |
| |
| if (Modifier.isStatic(method.modifiers)) { |
| // This is a top level or static method |
| method.invokeComposableMethod(null, composer, *args) |
| } else { |
| // The method is part of a class. We try to instantiate the class with an empty |
| // constructor. |
| val instance = composableClass.getConstructor().newInstance() |
| method.invokeComposableMethod(instance, composer, *args) |
| } |
| } catch (e: ReflectiveOperationException) { |
| throw ClassNotFoundException("Composable Method '$className.$methodName' not found", e) |
| } |
| } |
| |
| /** |
| * Tries to find the [KClass] of the [PreviewParameterProvider] corresponding to the given FQN. |
| */ |
| internal fun String.asPreviewProviderClass(): KClass<out PreviewParameterProvider<*>>? { |
| try { |
| @Suppress("UNCHECKED_CAST") |
| return Class.forName(this).kotlin as? KClass<out PreviewParameterProvider<*>> |
| } catch (e: ClassNotFoundException) { |
| Log.e("PreviewProvider", "Unable to find provider '$this'", e) |
| return null |
| } |
| } |
| |
| /** |
| * Returns an array with some values of a [PreviewParameterProvider]. If the given provider class |
| * is `null`, returns an empty array. Otherwise, if the given `parameterProviderIndex` is a valid |
| * index, returns a single-element array containing the value corresponding to that particular |
| * index in the provider's sequence. Finally, returns an array with all the values of the |
| * provider's sequence if `parameterProviderIndex` is invalid, e.g. negative. |
| */ |
| internal fun getPreviewProviderParameters( |
| parameterProviderClass: KClass<out PreviewParameterProvider<*>>?, |
| parameterProviderIndex: Int |
| ): Array<Any?> { |
| if (parameterProviderClass != null) { |
| try { |
| val constructor = parameterProviderClass.constructors |
| .singleOrNull { it.parameters.all(KParameter::isOptional) } |
| ?.apply { |
| isAccessible = true |
| } |
| ?: throw IllegalArgumentException( |
| "PreviewParameterProvider constructor can not" + |
| " have parameters" |
| ) |
| val params = constructor.callBy(emptyMap()) |
| if (parameterProviderIndex < 0) { |
| return params.values.toArray(params.count) |
| } |
| return arrayOf(params.values.elementAt(parameterProviderIndex)) |
| } catch (e: KotlinReflectionNotSupportedError) { |
| // kotlin-reflect runtime dependency not found. Suggest adding it. |
| throw IllegalStateException( |
| "Deploying Compose Previews with PreviewParameterProvider " + |
| "arguments requires adding a dependency to the kotlin-reflect library.\n" + |
| "Consider adding 'debugImplementation " + |
| "\"org.jetbrains.kotlin:kotlin-reflect:\$kotlin_version\"' " + |
| "to the module's build.gradle." |
| ) |
| } |
| } else { |
| return emptyArray() |
| } |
| } |
| |
| private fun Sequence<Any?>.toArray(size: Int): Array<Any?> { |
| val iter = iterator() |
| return Array(size) { iter.next() } |
| } |