diff options
Diffstat (limited to 'java/com/google/devtools/build/android/desugar/io/IndexedInputs.java')
-rw-r--r-- | java/com/google/devtools/build/android/desugar/io/IndexedInputs.java | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/java/com/google/devtools/build/android/desugar/io/IndexedInputs.java b/java/com/google/devtools/build/android/desugar/io/IndexedInputs.java new file mode 100644 index 0000000..8ce4b62 --- /dev/null +++ b/java/com/google/devtools/build/android/desugar/io/IndexedInputs.java @@ -0,0 +1,94 @@ +// Copyright 2017 The Bazel Authors. All rights reserved. +// +// 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 com.google.devtools.build.android.desugar.io; + +import static com.google.common.base.Preconditions.checkArgument; +import static com.google.common.base.Preconditions.checkState; + +import com.google.common.collect.ImmutableMap; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import javax.annotation.CheckReturnValue; +import javax.annotation.Nullable; + +/** + * Opens the given list of input files and compute an index of all classes in them, to avoid + * scanning all inputs over and over for each class to load. An indexed inputs can have a parent + * that is firstly used when a file name is searched. + */ +public class IndexedInputs { + + private final ImmutableMap<String, InputFileProvider> inputFiles; + + /** + * Parent {@link IndexedInputs} to use before to search a file name into this {@link + * IndexedInputs}. + */ + @Nullable + private final IndexedInputs parent; + + /** Index a list of input files without a parent {@link IndexedInputs}. */ + public IndexedInputs(List<InputFileProvider> inputProviders) { + this.parent = null; + this.inputFiles = indexInputs(inputProviders); + } + + /** + * Create a new {@link IndexedInputs} with input files previously indexed and with a parent {@link + * IndexedInputs}. + */ + private IndexedInputs( + ImmutableMap<String, InputFileProvider> inputFiles, IndexedInputs parentIndexedInputs) { + this.parent = parentIndexedInputs; + this.inputFiles = inputFiles; + } + + /** + * Create a new {@link IndexedInputs} with input files already indexed and with a parent {@link + * IndexedInputs}. + */ + @CheckReturnValue + public IndexedInputs withParent(IndexedInputs parent) { + checkState(this.parent == null); + return new IndexedInputs(this.inputFiles, parent); + } + + @Nullable + public InputFileProvider getInputFileProvider(String filename) { + checkArgument(filename.endsWith(".class")); + + if (parent != null) { + InputFileProvider inputFileProvider = parent.getInputFileProvider(filename); + if (inputFileProvider != null) { + return inputFileProvider; + } + } + + return inputFiles.get(filename); + } + + private ImmutableMap<String, InputFileProvider> indexInputs( + List<InputFileProvider> inputProviders) { + Map<String, InputFileProvider> indexedInputs = new HashMap<>(); + for (InputFileProvider inputProvider : inputProviders) { + for (String relativePath : inputProvider) { + if (relativePath.endsWith(".class") && !indexedInputs.containsKey(relativePath)) { + indexedInputs.put(relativePath, inputProvider); + } + } + } + return ImmutableMap.copyOf(indexedInputs); + } +} |