| // Copyright 2016 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; |
| |
| import com.google.devtools.build.android.desugar.io.CoreLibraryRewriter; |
| import com.google.devtools.build.android.desugar.io.IndexedInputs; |
| import com.google.devtools.build.android.desugar.io.InputFileProvider; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import javax.annotation.Nullable; |
| import org.objectweb.asm.ClassReader; |
| |
| class ClassReaderFactory { |
| private final IndexedInputs indexedInputs; |
| private final CoreLibraryRewriter rewriter; |
| |
| public ClassReaderFactory(IndexedInputs indexedInputs, CoreLibraryRewriter rewriter) { |
| this.rewriter = rewriter; |
| this.indexedInputs = indexedInputs; |
| } |
| |
| /** |
| * Returns a reader for the given/internal/Class$Name if the class is defined in the wrapped input |
| * and {@code null} otherwise. For simplicity this method turns checked into runtime exceptions |
| * under the assumption that all classes have already been read once when this method is called. |
| */ |
| @Nullable |
| public ClassReader readIfKnown(String internalClassName) { |
| String filename = rewriter.unprefix(internalClassName) + ".class"; |
| InputFileProvider inputFileProvider = indexedInputs.getInputFileProvider(filename); |
| |
| if (inputFileProvider != null) { |
| try (InputStream bytecode = inputFileProvider.getInputStream(filename)) { |
| // ClassReader doesn't take ownership and instead eagerly reads the stream's contents |
| return rewriter.reader(bytecode); |
| } catch (IOException e) { |
| // We should've already read through all files in the Jar once at this point, so we don't |
| // expect failures reading some files a second time. |
| throw new IllegalStateException("Couldn't load " + internalClassName, e); |
| } |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Returns {@code true} if the given given/internal/Class$Name is defined in the wrapped input. |
| */ |
| public boolean isKnown(String internalClassName) { |
| String filename = rewriter.unprefix(internalClassName) + ".class"; |
| return indexedInputs.getInputFileProvider(filename) != null; |
| } |
| } |