/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package sample.preproc;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Vector;
import javassist.CannotCompileException;
import javassist.CtClass;
import javassist.ClassPool;
/**
* This is a preprocessor for Java source programs using annotated
* import declarations.
*
* <ul><pre>
* import <i>class-name</i> by <i>assistant-name</i> [(<i>arg1, arg2, ...</i>)]
* </pre></ul>
*
* <p>To process this annotation, run this class as follows:
*
* <ul><pre>
* java sample.preproc.Compiler sample.j
* </pre></ul>
*
* <p>This command produces <code>sample.java</code>, which only includes
* regular import declarations. Also, the Javassist program
* specified by <i>assistant-name</i> is executed so that it produces
* class files under the <code>./tmpjvst</code> directory. The class
* specified by <i>assistant-name</i> must implement
* <code>sample.preproc.Assistant</code>.
*
* @see sample.preproc.Assistant
*/
public class Compiler {
protected BufferedReader input;
protected BufferedWriter output;
protected ClassPool classPool;
/**
* Constructs a <code>Compiler</code> with a source file.
*
* @param inputname the name of the source file.
*/
public Compiler(String inputname) throws CannotCompileException {
try {
input = new BufferedReader(new FileReader(inputname));
}
catch (IOException e) {
throw new CannotCompileException("cannot open: " + inputname);
}
String outputname = getOutputFilename(inputname);
if (outputname.equals(inputname))
throw new CannotCompileException("invalid source name: "
+ inputname);
try {
output = new BufferedWriter(new FileWriter(outputname));
}
catch (IOException e) {
throw new CannotCompileException("cannot open: " + outputname);
}
classPool = ClassPool.getDefault();
}
/**
* Starts preprocessing.
*/
public void process() throws IOException, CannotCompileException {
int c;
CommentSkipper reader = new CommentSkipper(input, output);
while ((c = reader.read()) != -1) {
output.write(c);
if (c == 'p') {
if (skipPackage(reader))
break;
}
else if (c == 'i')
readImport(reader);
else if (c != ' ' && c != '\t' && c != '\n' && c != '\r')
break;
}
while ((c = input.read()) != -1)
output.write(c);
input.close();
output.close();
}
private boolean skipPackage(CommentSkipper reader) throws IOException {
int c;
c = reader.read();
output.write(c);
if (c != 'a')
return true;
while ((c = reader.read()) != -1) {
output.write(c);
if (c == ';')
break;
}
return false;
}
private void readImport(CommentSkipper reader)
throws IOException, CannotCompileException
{
int word[] = new int[5];
int c;
for (int i = 0; i < 5; ++i) {
word[i] = reader.read();
output.write(word[i]);
}
if (word[0] != 'm' || word[1] != 'p' || word[2] != 'o'
|| word[3] != 'r' || word[4] != 't')
return; // syntax error?
c = skipSpaces(reader, ' ');
StringBuffer classbuf = new StringBuffer();
while (c != ' ' && c != '\t' && c != '\n' && c != '\r'
&& c != ';' && c != -1) {
classbuf.append((char)c);
c = reader.read();
}
String importclass = classbuf.toString();
c = skipSpaces(reader, c);
if (c == ';') {
output.write(importclass);
output.write(';');
return;
}
if (c != 'b')
syntaxError(importclass);
reader.read(); // skip 'y'
StringBuffer assistant = new StringBuffer();
Vector args = new Vector();
c = readAssistant(reader, importclass, assistant, args);
c = skipSpaces(reader, c);
if (c != ';')
syntaxError(importclass);
runAssistant(importclass, assistant.toString(), args);
}
void syntaxError(String importclass) throws CannotCompileException {
throw new CannotCompileException("Syntax error. Cannot import "
+ importclass);
}
int readAssistant(CommentSkipper reader, String importclass,
StringBuffer assistant, Vector args)
throws IOException, CannotCompileException
{
int c = readArgument(reader, assistant);
c = skipSpaces(reader, c);
if (c == '(') {
do {
StringBuffer arg = new StringBuffer();
c = readArgument(reader, arg);
args.addElement(arg.toString());
c = skipSpaces(reader, c);
} while (c == ',');
if (c != ')')
syntaxError(importclass);
return reader.read();
}
return c;
}
int readArgument(CommentSkipper reader, StringBuffer buf)
throws IOException
{
int c = skipSpaces(reader, ' ');
while ('A' <= c && c <= 'Z' || 'a' <= c && c <= 'z'
|| '0' <= c && c <= '9' || c == '.' || c == '_') {
buf.append((char)c);
c = reader.read();
}
return c;
}
int skipSpaces(CommentSkipper reader, int c) throws IOException {
while (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
if (c == '\n' || c == '\r')
output.write(c);
c = reader.read();
}
return c;
}
/**
* Is invoked if this compiler encoutenrs:
*
* <ul><pre>
* import <i>class name</i> by <i>assistant</i> (<i>args1</i>, <i>args2</i>, ...);
* </pre></ul>
*
* @param classname class name
* @param assistantname assistant
* @param argv args1, args2, ...
*/
private void runAssistant(String importname, String assistantname,
Vector argv)
throws IOException, CannotCompileException
{
Class assistant;
Assistant a;
int s = argv.size();
String[] args = new String[s];
for (int i = 0; i < s; ++i)
args[i] = (String)argv.elementAt(i);
try {
assistant = Class.forName(assistantname);
}
catch (ClassNotFoundException e) {
throw new CannotCompileException("Cannot find " + assistantname);
}
try {
a = (Assistant)assistant.newInstance();
}
catch (Exception e) {
throw new CannotCompileException(e);
}
CtClass[] imports = a.assist(classPool, importname, args);
s = imports.length;
if (s < 1)
output.write(" java.lang.Object;");
else {
output.write(' ');
output.write(imports[0].getName());
output.write(';');
for (int i = 1; i < s; ++i) {
output.write(" import ");
output.write(imports[1].getName());
output.write(';');
}
}
}
private String getOutputFilename(String input) {
int i = input.lastIndexOf('.');
if (i < 0)
i = input.length();
return input.substring(0, i) + ".java";
}
public static void main(String[] args) {
if (args.length > 0)
try {
Compiler c = new Compiler(args[0]);
c.process();
}
catch (IOException e) {
System.err.println(e);
}
catch (CannotCompileException e) {
System.err.println(e);
}
else {
System.err.println("Javassist version " + CtClass.version);
System.err.println("No source file is specified.");
}
}
}
class CommentSkipper {
private BufferedReader input;
private BufferedWriter output;
public CommentSkipper(BufferedReader reader, BufferedWriter writer) {
input = reader;
output = writer;
}
public int read() throws IOException {
int c;
while ((c = input.read()) != -1)
if (c != '/')
return c;
else {
c = input.read();
if (c == '/')
skipCxxComments();
else if (c == '*')
skipCComments();
else
output.write('/');
}
return c;
}
private void skipCxxComments() throws IOException {
int c;
output.write("//");
while ((c = input.read()) != -1) {
output.write(c);
if (c == '\n' || c == '\r')
break;
}
}
private void skipCComments() throws IOException {
int c;
boolean star = false;
output.write("/*");
while ((c = input.read()) != -1) {
output.write(c);
if (c == '*')
star = true;
else if(star && c == '/')
break;
else
star = false;
}
}
}