| /* |
| * Copyright (C) 2018 The Dagger Authors. |
| * |
| * 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 dagger.internal.codegen.writing; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.collect.Iterables.getLast; |
| import static com.google.common.collect.Iterables.getOnlyElement; |
| import static com.squareup.javapoet.MethodSpec.methodBuilder; |
| import static com.squareup.javapoet.TypeSpec.classBuilder; |
| import static dagger.internal.codegen.extension.DaggerStreams.toImmutableList; |
| import static dagger.internal.codegen.javapoet.AnnotationSpecs.Suppression.UNCHECKED; |
| import static dagger.internal.codegen.javapoet.AnnotationSpecs.suppressWarnings; |
| import static dagger.internal.codegen.javapoet.TypeNames.providerOf; |
| import static javax.lang.model.element.Modifier.FINAL; |
| import static javax.lang.model.element.Modifier.PRIVATE; |
| import static javax.lang.model.element.Modifier.PUBLIC; |
| import static javax.lang.model.element.Modifier.STATIC; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.collect.Lists; |
| import com.squareup.javapoet.ClassName; |
| import com.squareup.javapoet.CodeBlock; |
| import com.squareup.javapoet.MethodSpec; |
| import com.squareup.javapoet.TypeName; |
| import com.squareup.javapoet.TypeSpec; |
| import com.squareup.javapoet.TypeVariableName; |
| import dagger.internal.codegen.base.UniqueNameSet; |
| import dagger.internal.codegen.binding.ContributionBinding; |
| import dagger.internal.codegen.javapoet.CodeBlocks; |
| import dagger.internal.codegen.langmodel.DaggerTypes; |
| import dagger.internal.codegen.writing.ComponentImplementation.ShardImplementation; |
| import dagger.internal.codegen.writing.FrameworkFieldInitializer.FrameworkInstanceCreationExpression; |
| import dagger.spi.model.BindingKind; |
| import dagger.spi.model.Key; |
| import java.util.HashMap; |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| import java.util.TreeMap; |
| import javax.inject.Inject; |
| |
| /** |
| * Keeps track of all provider expression requests for a component. |
| * |
| * <p>The provider expression request will be satisfied by a single generated {@code Provider} class |
| * that can provide instances for all types by switching on an id. |
| */ |
| @PerComponentImplementation |
| final class SwitchingProviders { |
| /** |
| * Each switch size is fixed at 100 cases each and put in its own method. This is to limit the |
| * size of the methods so that we don't reach the "huge" method size limit for Android that will |
| * prevent it from being AOT compiled in some versions of Android (b/77652521). This generally |
| * starts to happen around 1500 cases, but we are choosing 100 to be safe. |
| */ |
| // TODO(bcorso): Include a proguard_spec in the Dagger library to prevent inlining these methods? |
| // TODO(ronshapiro): Consider making this configurable via a flag. |
| private static final int MAX_CASES_PER_SWITCH = 100; |
| |
| private static final long MAX_CASES_PER_CLASS = MAX_CASES_PER_SWITCH * MAX_CASES_PER_SWITCH; |
| private static final TypeVariableName T = TypeVariableName.get("T"); |
| |
| /** |
| * Maps a {@link Key} to an instance of a {@link SwitchingProviderBuilder}. Each group of {@code |
| * MAX_CASES_PER_CLASS} keys will share the same instance. |
| */ |
| private final Map<Key, SwitchingProviderBuilder> switchingProviderBuilders = |
| new LinkedHashMap<>(); |
| |
| private final ShardImplementation shardImplementation; |
| private final DaggerTypes types; |
| private final UniqueNameSet switchingProviderNames = new UniqueNameSet(); |
| |
| @Inject |
| SwitchingProviders(ComponentImplementation componentImplementation, DaggerTypes types) { |
| // Currently, the SwitchingProviders types are only added to the componentShard. |
| this.shardImplementation = checkNotNull(componentImplementation).getComponentShard(); |
| this.types = checkNotNull(types); |
| } |
| |
| /** Returns the framework instance creation expression for an inner switching provider class. */ |
| FrameworkInstanceCreationExpression newFrameworkInstanceCreationExpression( |
| ContributionBinding binding, RequestRepresentation unscopedInstanceRequestRepresentation) { |
| return new FrameworkInstanceCreationExpression() { |
| @Override |
| public CodeBlock creationExpression() { |
| return switchingProviderBuilders |
| .computeIfAbsent(binding.key(), key -> getSwitchingProviderBuilder()) |
| .getNewInstanceCodeBlock(binding, unscopedInstanceRequestRepresentation); |
| } |
| }; |
| } |
| |
| private SwitchingProviderBuilder getSwitchingProviderBuilder() { |
| if (switchingProviderBuilders.size() % MAX_CASES_PER_CLASS == 0) { |
| String name = switchingProviderNames.getUniqueName("SwitchingProvider"); |
| SwitchingProviderBuilder switchingProviderBuilder = |
| new SwitchingProviderBuilder(shardImplementation.name().nestedClass(name)); |
| shardImplementation.addTypeSupplier(switchingProviderBuilder::build); |
| return switchingProviderBuilder; |
| } |
| return getLast(switchingProviderBuilders.values()); |
| } |
| |
| // TODO(bcorso): Consider just merging this class with SwitchingProviders. |
| private final class SwitchingProviderBuilder { |
| // Keep the switch cases ordered by switch id. The switch Ids are assigned in pre-order |
| // traversal, but the switch cases are assigned in post-order traversal of the binding graph. |
| private final Map<Integer, CodeBlock> switchCases = new TreeMap<>(); |
| private final Map<Key, Integer> switchIds = new HashMap<>(); |
| private final ClassName switchingProviderType; |
| |
| SwitchingProviderBuilder(ClassName switchingProviderType) { |
| this.switchingProviderType = checkNotNull(switchingProviderType); |
| } |
| |
| private CodeBlock getNewInstanceCodeBlock( |
| ContributionBinding binding, RequestRepresentation unscopedInstanceRequestRepresentation) { |
| Key key = binding.key(); |
| if (!switchIds.containsKey(key)) { |
| int switchId = switchIds.size(); |
| switchIds.put(key, switchId); |
| switchCases.put( |
| switchId, createSwitchCaseCodeBlock(key, unscopedInstanceRequestRepresentation)); |
| } |
| return CodeBlock.of( |
| "new $T<$L>($L, $L)", |
| switchingProviderType, |
| // Add the type parameter explicitly when the binding is scoped because Java can't resolve |
| // the type when wrapped. For example, the following will error: |
| // fooProvider = DoubleCheck.provider(new SwitchingProvider<>(1)); |
| (binding.scope().isPresent() || binding.kind().equals(BindingKind.ASSISTED_FACTORY)) |
| ? CodeBlock.of( |
| "$T", types.accessibleType(binding.contributedType(), switchingProviderType)) |
| : "", |
| shardImplementation.componentFieldsByImplementation().values().stream() |
| .map(field -> CodeBlock.of("$N", field)) |
| .collect(CodeBlocks.toParametersCodeBlock()), |
| switchIds.get(key)); |
| } |
| |
| private CodeBlock createSwitchCaseCodeBlock( |
| Key key, RequestRepresentation unscopedInstanceRequestRepresentation) { |
| // TODO(bcorso): Try to delay calling getDependencyExpression() until we are writing out the |
| // SwitchingProvider because calling it here makes FrameworkFieldInitializer think there's a |
| // cycle when initializing SwitchingProviders which adds an uncessary DelegateFactory. |
| CodeBlock instanceCodeBlock = |
| unscopedInstanceRequestRepresentation |
| .getDependencyExpression(switchingProviderType) |
| .box(types) |
| .codeBlock(); |
| |
| return CodeBlock.builder() |
| // TODO(bcorso): Is there something else more useful than the key? |
| .add("case $L: // $L \n", switchIds.get(key), key) |
| .addStatement("return ($T) $L", T, instanceCodeBlock) |
| .build(); |
| } |
| |
| private TypeSpec build() { |
| TypeSpec.Builder builder = |
| classBuilder(switchingProviderType) |
| .addModifiers(PRIVATE, FINAL, STATIC) |
| .addTypeVariable(T) |
| .addSuperinterface(providerOf(T)) |
| .addMethods(getMethods()); |
| |
| // The SwitchingProvider constructor lists all component parameters first and switch id last. |
| MethodSpec.Builder constructor = MethodSpec.constructorBuilder(); |
| shardImplementation |
| .componentFieldsByImplementation() |
| .values() |
| .forEach( |
| field -> { |
| builder.addField(field); |
| constructor.addParameter(field.type, field.name); |
| constructor.addStatement("this.$1N = $1N", field); |
| }); |
| builder.addField(TypeName.INT, "id", PRIVATE, FINAL); |
| constructor.addParameter(TypeName.INT, "id").addStatement("this.id = id"); |
| |
| return builder.addMethod(constructor.build()).build(); |
| } |
| |
| private ImmutableList<MethodSpec> getMethods() { |
| ImmutableList<CodeBlock> switchCodeBlockPartitions = switchCodeBlockPartitions(); |
| if (switchCodeBlockPartitions.size() == 1) { |
| // There are less than MAX_CASES_PER_SWITCH cases, so no need for extra get methods. |
| return ImmutableList.of( |
| methodBuilder("get") |
| .addModifiers(PUBLIC) |
| .addAnnotation(suppressWarnings(UNCHECKED)) |
| .addAnnotation(Override.class) |
| .returns(T) |
| .addCode(getOnlyElement(switchCodeBlockPartitions)) |
| .build()); |
| } |
| |
| // This is the main public "get" method that will route to private getter methods. |
| MethodSpec.Builder routerMethod = |
| methodBuilder("get") |
| .addModifiers(PUBLIC) |
| .addAnnotation(Override.class) |
| .returns(T) |
| .beginControlFlow("switch (id / $L)", MAX_CASES_PER_SWITCH); |
| |
| ImmutableList.Builder<MethodSpec> getMethods = ImmutableList.builder(); |
| for (int i = 0; i < switchCodeBlockPartitions.size(); i++) { |
| MethodSpec method = |
| methodBuilder("get" + i) |
| .addModifiers(PRIVATE) |
| .addAnnotation(suppressWarnings(UNCHECKED)) |
| .returns(T) |
| .addCode(switchCodeBlockPartitions.get(i)) |
| .build(); |
| getMethods.add(method); |
| routerMethod.addStatement("case $L: return $N()", i, method); |
| } |
| |
| routerMethod.addStatement("default: throw new $T(id)", AssertionError.class).endControlFlow(); |
| |
| return getMethods.add(routerMethod.build()).build(); |
| } |
| |
| private ImmutableList<CodeBlock> switchCodeBlockPartitions() { |
| return Lists.partition(ImmutableList.copyOf(switchCases.values()), MAX_CASES_PER_SWITCH) |
| .stream() |
| .map( |
| partitionCases -> |
| CodeBlock.builder() |
| .beginControlFlow("switch (id)") |
| .add(CodeBlocks.concat(partitionCases)) |
| .addStatement("default: throw new $T(id)", AssertionError.class) |
| .endControlFlow() |
| .build()) |
| .collect(toImmutableList()); |
| } |
| } |
| } |