gradle-master/subprojects/language-java/src/main/java/org/gradle/api/internal/tasks/compile/incremental/recomp/RecompilationSpecProvider.java
/*
 * Copyright 2019 the original author or 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 org.gradle.api.internal.tasks.compile.incremental.recomp;

import org.gradle.api.internal.tasks.compile.JavaCompileSpec;
import org.gradle.api.internal.tasks.compile.incremental.transaction.CompileTransaction;
import org.gradle.api.tasks.WorkResult;

/**
 * In a typical incremental recompilation, there're three steps:
 * First, examine the incremental change files to get the classes to be recompiled: {@link #provideRecompilationSpec(JavaCompileSpec, CurrentCompilation, PreviousCompilation)}
 * Second, initialize the recompilation (e.g. delete stale class files and narrow down the source files to be recompiled): {@link #initCompilationSpecAndTransaction(JavaCompileSpec, RecompilationSpec)}
 * Third, decorate the compilation result if necessary: {@link #decorateResult(RecompilationSpec, PreviousCompilationData, WorkResult)}, for example, notify whether current recompilation is full recompilation.
 */
public interface RecompilationSpecProvider {

    boolean isIncremental();

    RecompilationSpec provideRecompilationSpec(JavaCompileSpec spec, CurrentCompilation current, PreviousCompilation previous);

    CompileTransaction initCompilationSpecAndTransaction(JavaCompileSpec spec, RecompilationSpec recompilationSpec);

    default WorkResult decorateResult(RecompilationSpec recompilationSpec, PreviousCompilationData previousCompilationData, WorkResult workResult) {
        if (!recompilationSpec.isFullRebuildNeeded()) {
            return new DefaultIncrementalCompileResult(previousCompilationData, recompilationSpec, workResult);
        }
        return workResult;
    }
}
