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| 1 | +// Copyright 2022 The Bazel Authors. All rights reserved. |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +package com.google.devtools.build.runfiles; |
| 16 | + |
| 17 | +import java.io.IOException; |
| 18 | +import java.io.PrintWriter; |
| 19 | +import java.util.ArrayDeque; |
| 20 | +import java.util.Deque; |
| 21 | +import java.util.Set; |
| 22 | +import javax.annotation.processing.AbstractProcessor; |
| 23 | +import javax.annotation.processing.RoundEnvironment; |
| 24 | +import javax.annotation.processing.SupportedAnnotationTypes; |
| 25 | +import javax.annotation.processing.SupportedOptions; |
| 26 | +import javax.lang.model.SourceVersion; |
| 27 | +import javax.lang.model.element.Element; |
| 28 | +import javax.lang.model.element.TypeElement; |
| 29 | +import javax.tools.Diagnostic.Kind; |
| 30 | + |
| 31 | +/** Processor for {@link AutoBazelRepository}. */ |
| 32 | +@SupportedAnnotationTypes("com.google.devtools.build.runfiles.AutoBazelRepository") |
| 33 | +@SupportedOptions(AutoBazelRepositoryProcessor.BAZEL_REPOSITORY_OPTION) |
| 34 | +public final class AutoBazelRepositoryProcessor extends AbstractProcessor { |
| 35 | + |
| 36 | + static final String BAZEL_REPOSITORY_OPTION = "bazel.repository"; |
| 37 | + |
| 38 | + @Override |
| 39 | + public SourceVersion getSupportedSourceVersion() { |
| 40 | + return SourceVersion.latestSupported(); |
| 41 | + } |
| 42 | + |
| 43 | + @Override |
| 44 | + public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) { |
| 45 | + annotations.stream() |
| 46 | + .flatMap(element -> roundEnv.getElementsAnnotatedWith(element).stream()) |
| 47 | + .map(element -> (TypeElement) element) |
| 48 | + .forEach(this::emitClass); |
| 49 | + return false; |
| 50 | + } |
| 51 | + |
| 52 | + private void emitClass(TypeElement annotatedClass) { |
| 53 | + // This option is always provided by the Java rule implementations. |
| 54 | + if (!processingEnv.getOptions().containsKey(BAZEL_REPOSITORY_OPTION)) { |
| 55 | + processingEnv |
| 56 | + .getMessager() |
| 57 | + .printMessage( |
| 58 | + Kind.ERROR, |
| 59 | + String.format( |
| 60 | + "The %1$s annotation processor option is not set. To use this annotation" |
| 61 | + + " processor, provide the canonical repository name of the current target as" |
| 62 | + + " the value of the -A%1$s flag.", |
| 63 | + BAZEL_REPOSITORY_OPTION), |
| 64 | + annotatedClass); |
| 65 | + return; |
| 66 | + } |
| 67 | + String repositoryName = processingEnv.getOptions().get(BAZEL_REPOSITORY_OPTION); |
| 68 | + if (repositoryName == null) { |
| 69 | + // javac translates '-Abazel.repository=' into a null value. |
| 70 | + // https://github.com/openjdk/jdk/blob/7a49c9baa1d4ad7df90e7ca626ec48ba76881822/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#L651 |
| 71 | + repositoryName = ""; |
| 72 | + } |
| 73 | + |
| 74 | + // For a nested class Outer.Middle.Inner, generate a class with simple name |
| 75 | + // AutoBazelRepository_Outer_Middle_Inner. |
| 76 | + // Note: There can be collisions when local classes are involved, but since the definition of a |
| 77 | + // class depends only on the containing Bazel target, this does not result in ambiguity. |
| 78 | + Deque<String> classNameSegments = new ArrayDeque<>(); |
| 79 | + Element element = annotatedClass; |
| 80 | + while (element instanceof TypeElement) { |
| 81 | + classNameSegments.addFirst(element.getSimpleName().toString()); |
| 82 | + element = element.getEnclosingElement(); |
| 83 | + } |
| 84 | + classNameSegments.addFirst("AutoBazelRepository"); |
| 85 | + String generatedClassSimpleName = String.join("_", classNameSegments); |
| 86 | + |
| 87 | + String generatedClassPackage = |
| 88 | + processingEnv.getElementUtils().getPackageOf(annotatedClass).getQualifiedName().toString(); |
| 89 | + |
| 90 | + String generatedClassName = |
| 91 | + generatedClassPackage.isEmpty() |
| 92 | + ? generatedClassSimpleName |
| 93 | + : generatedClassPackage + "." + generatedClassSimpleName; |
| 94 | + |
| 95 | + try (PrintWriter out = |
| 96 | + new PrintWriter( |
| 97 | + processingEnv.getFiler().createSourceFile(generatedClassName).openWriter())) { |
| 98 | + if (!generatedClassPackage.isEmpty()) { |
| 99 | + // This annotation may exist on a class which is at the root package |
| 100 | + out.printf("package %s;\n", generatedClassPackage); |
| 101 | + } |
| 102 | + out.printf("\n"); |
| 103 | + out.printf("class %s {\n", generatedClassSimpleName); |
| 104 | + out.printf(" /**\n"); |
| 105 | + out.printf(" * The canonical name of the repository containing the Bazel target that\n"); |
| 106 | + out.printf(" * compiled {@link %s}.\n", annotatedClass.getQualifiedName().toString()); |
| 107 | + out.printf(" */\n"); |
| 108 | + out.printf(" static final String NAME = \"%s\";\n", repositoryName); |
| 109 | + out.printf("\n"); |
| 110 | + out.printf(" private %s() {}\n", generatedClassSimpleName); |
| 111 | + out.printf("}\n"); |
| 112 | + } catch (IOException e) { |
| 113 | + processingEnv |
| 114 | + .getMessager() |
| 115 | + .printMessage( |
| 116 | + Kind.ERROR, |
| 117 | + String.format("Failed to generate %s: %s", generatedClassName, e.getMessage()), |
| 118 | + annotatedClass); |
| 119 | + } |
| 120 | + } |
| 121 | +} |
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