com.threerings.presents.tools.GenTask Maven / Gradle / Ivy
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//
// $Id$
//
// Narya library - tools for developing networked games
// Copyright (C) 2002-2012 Three Rings Design, Inc., All Rights Reserved
// http://code.google.com/p/narya/
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package com.threerings.presents.tools;
import static com.google.common.base.Charsets.UTF_8;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.tools.ant.AntClassLoader;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.FileSet;
import org.apache.tools.ant.types.Reference;
import org.apache.tools.ant.util.ClasspathUtils;
import com.google.common.base.Splitter;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.google.common.io.Files;
import com.samskivert.io.StreamUtil;
import com.samskivert.mustache.Mustache;
public abstract class GenTask extends Task
{
/**
* Adds a nested <fileset> element which enumerates service declaration source files.
*/
public void addFileset (FileSet set)
{
_filesets.add(set);
}
/**
* Configures us with a header file that we'll prepend to all
* generated source files.
*/
public void setHeader (File header)
{
try {
_header = StreamUtil.toString(new FileReader(header));
} catch (IOException ioe) {
System.err.println("Unabled to load header '" + header + ": " +
ioe.getMessage());
}
}
/** Configures our classpath which we'll use to load service classes. */
public void setClasspathref (Reference pathref)
{
_cloader = ClasspathUtils.getClassLoaderForPath(getProject(), pathref);
// set the parent of the classloader to be the classloader used to load this task, rather
// than the classloader used to load Ant, so that we have access to Narya classes like
// TransportHint
((AntClassLoader)_cloader).setParent(getClass().getClassLoader());
}
/**
* Fails the build if generation would change files rather than generating
* code.
*/
public void setChecking (boolean checking)
{
_checking = checking;
}
/**
* Performs the actual work of the task.
*/
@Override
public void execute ()
{
if (_checking) {
log("Only checking if generation would change files", Project.MSG_VERBOSE);
}
for (FileSet fs : _filesets) {
DirectoryScanner ds = fs.getDirectoryScanner(getProject());
File fromDir = fs.getDir(getProject());
String[] srcFiles = ds.getIncludedFiles();
for (String srcFile : srcFiles) {
File source = new File(fromDir, srcFile);
try {
processClass(source, loadClass(source));
} catch (Exception e) {
throw new BuildException(e);
}
}
}
if (_checking && !_modifiedPaths.isEmpty()) {
throw new BuildException("Generation would produce changes!");
}
}
protected void writeTemplate (String templatePath, String outputPath, Object... data)
throws IOException
{
writeTemplate(templatePath, outputPath, createMap(data));
}
protected void writeTemplate (String templatePath, String outputPath, Map data)
throws IOException
{
String output = mergeTemplate(templatePath, data);
if (_header != null) {
output = convertEols(_header) + output;
}
writeFile(outputPath, output);
}
protected void writeFile (String outputPath, String output) throws IOException
{
File dest = new File(outputPath);
if (dest.exists()) {
if (wouldProduceSameFile(output, dest)) {
log("Skipping '" + outputPath + "' as it hasn't changed", Project.MSG_VERBOSE);
return;
}
} else if (!dest.getParentFile().exists() && !dest.getParentFile().mkdirs()) {
throw new BuildException("Unable to create directory for '" + dest.getAbsolutePath() + "'");
}
_modifiedPaths.add(outputPath);
if (_checking) {
log("Generating '" + outputPath + "' would have produced changes!", Project.MSG_ERR);
return;
}
log("Writing file " + outputPath, Project.MSG_VERBOSE);
new PrintWriter(dest, "UTF-8").append(output).close();
}
/**
* Returns true if the given string has the same content as the file, sans svn prop lines.
*/
protected boolean wouldProduceSameFile (String generated, File existing)
throws IOException
{
Iterator generatedLines = Splitter.on(EOL).split(generated).iterator();
for (String prev : Files.readLines(existing, UTF_8)) {
if (!generatedLines.hasNext()) {
return false;
}
String cur = generatedLines.next();
if (!prev.equals(cur) && !(prev.startsWith("// $Id") && cur.startsWith("// $Id"))) {
return false;
}
}
// If the generated output ends with a newline, it'll have one more next from the splitter
// that reading the file doesn't produce.
if (generatedLines.hasNext()) {
return generatedLines.next().equals("") && !generatedLines.hasNext();
}
return true;
}
/**
* Merges the specified template using the supplied mapping of keys to objects.
*
* @param data a series of key, value pairs where the keys must be strings and the values can
* be any object.
*/
protected String mergeTemplate (String template, Object... data)
throws IOException
{
return mergeTemplate(template, createMap(data));
}
/**
* Merges the specified template using the supplied mapping of string keys to objects.
*
* @return a string containing the merged text.
*/
protected String mergeTemplate (String template, Map data)
throws IOException
{
Reader reader =
new InputStreamReader(getClass().getClassLoader().getResourceAsStream(template), UTF_8);
return convertEols(Mustache.compiler().escapeHTML(false).compile(reader).execute(data));
}
protected Map createMap (Object... data)
{
Map ctx = Maps.newHashMap();
for (int ii = 0; ii < data.length; ii += 2) {
ctx.put((String)data[ii], data[ii+1]);
}
return ctx;
}
/**
* Process a class found from the given source file that was on the filesets given to this
* task.
*/
protected abstract void processClass (File source, Class klass)
throws Exception;
protected Class loadClass (File source)
{
// load up the file and determine it's package and classname
String name;
try {
name = GenUtil.readClassName(source);
} catch (Exception e) {
throw new BuildException("Failed to parse " + source, e);
}
return loadClass(name);
}
protected Class loadClass (String name)
{
if (_cloader == null) {
throw new BuildException("This task requires a 'classpathref' attribute " +
"to be set to the project's classpath.");
}
try {
return _cloader.loadClass(name);
} catch (ClassNotFoundException cnfe) {
throw new BuildException(
"Failed to load " + name + ". Be sure to set the 'classpathref' attribute to a " +
"classpath that contains your project's presents classes.", cnfe);
}
}
protected String convertEols (String str)
{
return str.replace("\n", EOL);
}
protected static String EOL = System.getProperty("line.separator");
/** A list of filesets that contain java source to be processed. */
protected List _filesets = Lists.newArrayList();
/** Used to do our own classpath business. */
protected ClassLoader _cloader;
/** A header to put on all generated source files. */
protected String _header;
protected boolean _checking;
protected Set _modifiedPaths = Sets.newHashSet();
}