LombokFileObjects.java

/*
 * Copyright (C) 2010-2011 The Project Lombok Authors.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package lombok.javac.apt;

import java.lang.reflect.Method;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.tools.JavaFileManager;
import javax.tools.JavaFileObject;
import javax.tools.JavaFileObject.Kind;

import lombok.core.DiagnosticsReceiver;

//Can't use SimpleJavaFileObject so we copy/paste most of its content here, because javac doesn't follow the interface,
//and casts to its own BaseFileObject type. D'oh!
final class LombokFileObjects {
	enum Compiler {
		JAVAC6 {
			private Method decoderMethod = null;
			private final AtomicBoolean decoderIsSet = new AtomicBoolean();
			
			@Override public JavaFileObject wrap(LombokFileObject fileObject) {
				return new Javac6BaseFileObjectWrapper(fileObject);
			}
			
			@Override public Method getDecoderMethod() {
				synchronized (decoderIsSet) {
					if (decoderIsSet.get()) return decoderMethod;
					decoderMethod = getDecoderMethod("com.sun.tools.javac.util.BaseFileObject");
					decoderIsSet.set(true);
					return decoderMethod;
				}
			}
		},
		JAVAC7 {
			private Method decoderMethod = null;
			private final AtomicBoolean decoderIsSet = new AtomicBoolean();
			
			@Override public JavaFileObject wrap(LombokFileObject fileObject) {
				return new Javac7BaseFileObjectWrapper(fileObject);
			}
			
			@Override public Method getDecoderMethod() {
				synchronized (decoderIsSet) {
					if (decoderIsSet.get()) return decoderMethod;
					decoderMethod = getDecoderMethod("com.sun.tools.javac.file.BaseFileObject");
					decoderIsSet.set(true);
					return decoderMethod;
				}
			}
		};
		
		static Method getDecoderMethod(String className) {
			Method m = null;
			try {
				m = Class.forName(className).getDeclaredMethod("getDecoder", boolean.class);
				m.setAccessible(true);
			} catch (NoSuchMethodException e) {
				// Intentional fallthrough - getDecoder(boolean) is not always present.
			} catch (ClassNotFoundException e) {
				// Intentional fallthrough - getDecoder(boolean) is not always present.
			}
			return m;
		}
		
		abstract JavaFileObject wrap(LombokFileObject fileObject);
		abstract Method getDecoderMethod();
	}
	
	private LombokFileObjects() {}
	
	static Compiler getCompiler(JavaFileManager jfm) {
		String jfmClassName = jfm != null ? jfm.getClass().getName() : "null";
		if (jfmClassName.equals("com.sun.tools.javac.util.DefaultFileManager")) return Compiler.JAVAC6;
		if (jfmClassName.equals("com.sun.tools.javac.util.JavacFileManager")) return Compiler.JAVAC6;
		if (jfmClassName.equals("com.sun.tools.javac.file.JavacFileManager")) return Compiler.JAVAC7;
		try {
			if (Class.forName("com.sun.tools.javac.file.BaseFileObject") == null) throw new NullPointerException();
			return Compiler.JAVAC7;
		} catch (Exception e) {}
		try {
			if (Class.forName("com.sun.tools.javac.util.BaseFileObject") == null) throw new NullPointerException();
			return Compiler.JAVAC6;
		} catch (Exception e) {}
		return null;
	}
	
	static JavaFileObject createEmpty(Compiler compiler, String name, Kind kind) {
		return compiler.wrap(new EmptyLombokFileObject(name, kind));
	}
	
	static JavaFileObject createIntercepting(Compiler compiler, JavaFileObject delegate, String fileName, DiagnosticsReceiver diagnostics) {
		return compiler.wrap(new InterceptingJavaFileObject(delegate, fileName, diagnostics, compiler.getDecoderMethod()));
	}
}