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StringTemplate is a java template engine for generating source code, web pages, emails, or any other formatted text output. StringTemplate is particularly good at multi-targeted code generators, multiple site skins, and internationalization/localization. It evolved over years of effort developing jGuru.com. StringTemplate also powers the ANTLR 3 and 4 code generator. Its distinguishing characteristic is that unlike other engines, it strictly enforces model-view separation. Strict separation makes websites and code generators more flexible and maintainable; it also provides an excellent defense against malicious template authors.

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/*
 * [The "BSD license"]
 *  Copyright (c) 2011 Terence Parr
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.stringtemplate.v4;

import org.antlr.runtime.*;
import org.stringtemplate.v4.compiler.*;
import org.stringtemplate.v4.misc.*;

import java.io.*;
import java.net.*;

// TODO: caching?

/** A directory or directory tree full of templates and/or group files.
 *  We load files on-demand. Dir search path: current working dir then
 *  CLASSPATH (as a resource).  Do not look for templates outside of this dir
 *  subtree (except via imports).
 */
public class STGroupDir extends STGroup {
    public String groupDirName;
    public URL root;

    public STGroupDir(String dirName) { this(dirName, '<', '>'); }

    public STGroupDir(String dirName, char delimiterStartChar, char delimiterStopChar) {
        super(delimiterStartChar, delimiterStopChar);
        this.groupDirName = dirName;
		File dir = new File(dirName);
		if ( dir.exists() && dir.isDirectory() ) {
			// we found the directory and it'll be file based
			try {
				root = dir.toURI().toURL();
			}
			catch (MalformedURLException e) {
				throw new STException("can't load dir "+dirName, e);
			}
			if ( verbose ) System.out.println("STGroupDir("+dirName+") found at "+root);
		}
		else {
			ClassLoader cl = Thread.currentThread().getContextClassLoader();
			root = cl.getResource(dirName);
			if ( root==null ) {
				cl = this.getClass().getClassLoader();
				root = cl.getResource(dirName);
			}
			if ( verbose ) System.out.println("STGroupDir("+dirName+") found via CLASSPATH at "+root);
			if ( root==null ) {
				throw new IllegalArgumentException("No such directory: "+
													   dirName);
			}
		}
	}

	public STGroupDir(String dirName, String encoding) {
        this(dirName, encoding, '<', '>');
    }

    public STGroupDir(String dirName, String encoding,
                      char delimiterStartChar, char delimiterStopChar)
    {
        this(dirName, delimiterStartChar, delimiterStopChar);
        this.encoding = encoding;
    }

	public STGroupDir(URL root, String encoding,
					  char delimiterStartChar, char delimiterStopChar)
	{
		super(delimiterStartChar, delimiterStopChar);
		this.groupDirName = new File(root.getFile()).getName();
		this.root = root;
		this.encoding = encoding;
	}

	@Override
	public void importTemplates(Token fileNameToken) {
		String msg =
			"import illegal in group files embedded in STGroupDirs; "+
			"import "+fileNameToken.getText()+" in STGroupDir "+this.getName();
		throw new UnsupportedOperationException(msg);
	}

	/** Load a template from directory or group file.  Group file is given
	 *  precedence over directory with same name. {@code name} is always fully-qualified.
     */
	@Override
    protected CompiledST load(String name) {
		if ( verbose ) System.out.println("STGroupDir.load("+name+")");
        String parent = Misc.getParent(name); // must have parent; it's fully-qualified
		String prefix = Misc.getPrefix(name);
//    	if (parent.isEmpty()) {
//    		// no need to check for a group file as name has no parent
//            return loadTemplateFile("/", name+TEMPLATE_FILE_EXTENSION); // load t.st file
//    	}

        URL groupFileURL = null;
        try { // see if parent of template name is a group file
            groupFileURL = new URL(root+parent+GROUP_FILE_EXTENSION);
        }
        catch (MalformedURLException e) {
            errMgr.internalError(null, "bad URL: "+root+parent+GROUP_FILE_EXTENSION, e);
			return null;
        }

        InputStream is = null;
        try {
            is = groupFileURL.openStream();
        }
        catch (IOException ioe) {
            // must not be in a group file
			String unqualifiedName = Misc.getFileName(name);
            return loadTemplateFile(prefix, unqualifiedName+TEMPLATE_FILE_EXTENSION); // load t.st file
		}
        finally { // clean up
			try {
				if (is!=null ) is.close();
			}
			catch (IOException ioe) {
				errMgr.internalError(null, "can't close template file stream "+name, ioe);
			}
        }

        loadGroupFile(prefix, root+parent+GROUP_FILE_EXTENSION);
        return rawGetTemplate(name);
    }

	/** Load .st as relative file name relative to root by {@code prefix}. */
	public CompiledST loadTemplateFile(String prefix, String unqualifiedFileName) {
		if ( verbose ) System.out.println("loadTemplateFile("+unqualifiedFileName+") in groupdir "+
										  "from "+root+" prefix="+prefix);
		URL f = null;
		try {
			f = new URL(root+prefix+unqualifiedFileName);
		}
		catch (MalformedURLException me) {
			errMgr.runTimeError(null, null, ErrorType.INVALID_TEMPLATE_NAME,
								me, root + unqualifiedFileName);
			return null;
		}

		ANTLRInputStream fs;
		try {
			fs = new ANTLRInputStream(f.openStream(), encoding);
			fs.name = unqualifiedFileName;
		}
		catch (IOException ioe) {
			if ( verbose ) System.out.println(root+"/"+unqualifiedFileName+" doesn't exist");
			//errMgr.IOError(null, ErrorType.NO_SUCH_TEMPLATE, ioe, unqualifiedFileName);
			return null;
		}

		return loadTemplateFile(prefix, unqualifiedFileName, fs);
	}

	@Override
	public String getName() { return groupDirName; }
	@Override
	public String getFileName() { return root.getFile(); }
	@Override
	public URL getRootDirURL() { return root; }
}