/***** BEGIN LICENSE BLOCK *****
 * Version: CPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Common Public
 * License Version 1.0 (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.eclipse.org/legal/cpl-v10.html
 *
 * 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.
 *
 * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2002-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
 * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
 * 
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package org.jruby.parser;

import java.io.Reader;
import java.io.StringReader;

import org.jruby.Ruby;
import org.jruby.RubyFile;
import org.jruby.ast.Node;
import org.jruby.lexer.yacc.LexerSource;
import org.jruby.lexer.yacc.SyntaxException;
import org.jruby.runtime.DynamicScope;
import org.jruby.runtime.ThreadContext;
import org.jruby.util.collections.SinglyLinkedList;

/**
 * Serves as a simple facade for all the parsing magic.
 */
public class Parser {
    private final Ruby runtime;

    public Parser(Ruby runtime) {
        this.runtime = runtime;
    }

    public Node parse(String file, String content, DynamicScope blockScope, int lineNumber) {
        return parse(file, new StringReader(content), blockScope, lineNumber);
    }

    public Node parse(String file, Reader content, DynamicScope blockScope, int lineNumber) {
        RubyParserConfiguration configuration = new RubyParserConfiguration(); 
        SinglyLinkedList cref = runtime.getObject().getCRef();
        ThreadContext tc = runtime.getCurrentContext();

        // We only need to pass in current scope if we are evaluating as a block (which
        // is only done for evals).  We need to pass this in so that we can appropriately scope
        // down to captured scopes when we are parsing.
        if (blockScope != null) {
            configuration.parseAsBlock(blockScope);
        }
        
        DefaultRubyParser parser = null;
        RubyParserResult result = null;
        try {
            parser = RubyParserPool.getInstance().borrowParser();
            parser.setWarnings(runtime.getWarnings());
            tc.setCRef(cref);
            LexerSource lexerSource = LexerSource.getSource(file, content, lineNumber);
            result = parser.parse(configuration, lexerSource);
            if (result.isEndSeen()) {
                org.jruby.runtime.builtin.IRubyObject verbose = runtime.getVerbose();
                runtime.setVerbose(runtime.getNil());
            	runtime.defineGlobalConstant("DATA", new RubyFile(runtime, file, content));
                runtime.setVerbose(verbose);
            	result.setEndSeen(false);
            }
        } catch (SyntaxException e) {
            StringBuffer buffer = new StringBuffer(100);
            buffer.append(e.getPosition().getFile()).append(':');
            buffer.append(e.getPosition().getEndLine()).append(": ");
            buffer.append(e.getMessage());
            throw runtime.newSyntaxError(buffer.toString());
        } finally {
            RubyParserPool.getInstance().returnParser(parser);
            tc.unsetCRef();
        }
        
        // If variables were added then we may need to grow the dynamic scope to match the static
        // one.
        // FIXME: Make this so we only need to check this for blockScope != null.  We cannot
        // currently since we create the DynamicScope for a LocalStaticScope before parse begins.
        // Refactoring should make this fixable.
        if (result.getScope() != null) {
            result.getScope().growIfNeeded();
        }

        // FIXME: We should move this into ParserSupport.addRootNode since actual parser should do this.
        result.addAppendBeginNodes();
        return result.getAST();
    }
}
