| /* |
| * 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.compose.runtime.reflect |
| |
| import androidx.compose.runtime.Composer |
| import androidx.compose.runtime.internal.SLOTS_PER_INT |
| import java.lang.reflect.Method |
| import java.lang.reflect.Modifier |
| import java.lang.reflect.Parameter |
| import kotlin.math.ceil |
| |
| private inline fun <reified T> T.dup(count: Int): Array<T> { |
| return (0 until count).map { this }.toTypedArray() |
| } |
| |
| /** |
| * Find the given @Composable method by name. |
| */ |
| @Throws(NoSuchMethodException::class) |
| fun Class<*>.getDeclaredComposableMethod(methodName: String, vararg args: Class<*>): Method { |
| val changedParams = changedParamCount(args.size, 0) |
| val method = try { |
| // without defaults |
| getDeclaredMethod( |
| methodName, |
| *args, |
| Composer::class.java, // composer param |
| *Int::class.java.dup(changedParams) // changed params |
| ) |
| } catch (e: ReflectiveOperationException) { |
| val defaultParams = defaultParamCount(args.size) |
| try { |
| getDeclaredMethod( |
| methodName, |
| *args, |
| Composer::class.java, // composer param |
| *Int::class.java.dup(changedParams), // changed param |
| *Int::class.java.dup(defaultParams) // default param |
| ) |
| } catch (e2: 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 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.toChar() |
| else -> null |
| } |
| |
| /** |
| * Structure intended to be used exclusively by [getComposableInfo]. |
| */ |
| private data class ComposableInfo( |
| val isComposable: Boolean, |
| val realParamsCount: Int, |
| val changedParams: Int, |
| val defaultParams: Int |
| ) |
| |
| /** |
| * Checks whether the method is Composable function and returns result along with the real |
| * parameters count and changed parameter count (if composable) and packed in a structure. |
| */ |
| private fun Method.getComposableInfo(): ComposableInfo { |
| val realParamsCount = parameterTypes.indexOfLast { it == Composer::class.java } |
| if (realParamsCount == -1) { |
| return ComposableInfo(false, parameterTypes.size, 0, 0) |
| } |
| val thisParams = if (Modifier.isStatic(this.modifiers)) 0 else 1 |
| val changedParams = changedParamCount(realParamsCount, thisParams) |
| val totalParamsWithoutDefaults = realParamsCount + |
| 1 + // composer |
| changedParams |
| val totalParams = parameterTypes.size |
| val isDefault = totalParams != totalParamsWithoutDefaults |
| val defaultParams = if (isDefault) |
| defaultParamCount(realParamsCount) |
| else |
| 0 |
| return ComposableInfo( |
| totalParamsWithoutDefaults + defaultParams == totalParams, |
| realParamsCount, |
| changedParams, |
| defaultParams |
| ) |
| } |
| |
| /** |
| * Calls the Composable method on the given [instance]. If the method accepts default values, this |
| * function will call it with the correct options set. |
| */ |
| @Suppress("BanUncheckedReflection", "ListIterator") |
| fun Method.invokeComposable( |
| composer: Composer, |
| instance: Any?, |
| vararg args: Any? |
| ): Any? { |
| val (isComposable, realParamsCount, changedParams, defaultParams) = getComposableInfo() |
| |
| check(isComposable) |
| |
| val totalParams = parameterTypes.size |
| val changedStartIndex = realParamsCount + 1 |
| val defaultStartIndex = changedStartIndex + changedParams |
| |
| val defaultsMasks = Array(defaultParams) { index -> |
| val start = index * BITS_PER_INT |
| val end = minOf(start + BITS_PER_INT, realParamsCount) |
| val useDefault = |
| (start until end).map { if (it >= args.size || args[it] == null) 1 else 0 } |
| val mask = useDefault.foldIndexed(0) { i, mask, default -> mask or (default shl i) } |
| mask |
| } |
| |
| val arguments = Array(totalParams) { idx -> |
| when (idx) { |
| // pass in "empty" value for all real parameters since we will be using defaults. |
| in 0 until realParamsCount -> args.getOrElse(idx) { |
| parameterTypes[idx].getDefaultValue() |
| } |
| // the composer is the first synthetic parameter |
| realParamsCount -> composer |
| // since this is the root we don't need to be anything unique. 0 should suffice. |
| // changed parameters should be 0 to indicate "uncertain" |
| changedStartIndex -> 1 |
| in changedStartIndex + 1 until defaultStartIndex -> 0 |
| // Default values mask, all parameters set to use defaults |
| in defaultStartIndex until totalParams -> defaultsMasks[idx - defaultStartIndex] |
| else -> error("Unexpected index") |
| } |
| } |
| return invoke(instance, *arguments) |
| } |
| |
| 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() |
| } |
| |
| /** |
| * Returns true if the method is a Composable function and false otherwise. |
| */ |
| val Method.isComposable: Boolean |
| get() = getComposableInfo().isComposable |
| |
| /** |
| * Returns real parameters count for the method, it returns the actual parameters count for the |
| * usual methods and for Composable functions it excludes the utility Compose-specific parameters |
| * from counting. |
| */ |
| val Method.realParametersCount: Int |
| get() { |
| val (isComposable, realParametersCount, _, _) = getComposableInfo() |
| if (isComposable) { |
| return realParametersCount |
| } |
| return parameterTypes.size |
| } |
| |
| /** |
| * Returns real parameters for the method, it returns the actual parameters for the usual methods |
| * and for Composable functions it excludes the utility Compose-specific parameters. |
| */ |
| val Method.realParameters: Array<out Parameter> |
| @Suppress("ClassVerificationFailure", "NewApi") |
| get() { |
| val (isComposable, realParametersCount, _, _) = getComposableInfo() |
| if (isComposable) { |
| return parameters.copyOfRange(0, realParametersCount) |
| } |
| return parameters |
| } |