opensim/OpenSim/Region/ScriptEngine/XMREngine/MMRScriptCompile.cs

/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 CONTRIBUTORS 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.
 */

/**
 * @brief Compile a script to produce a ScriptObjCode object
 */

using System;
using System.IO;
using System.IO.Compression;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;

namespace OpenSim.Region.ScriptEngine.XMREngine
{
    public partial class XMRInstance
    {
        /**
         * @brief Compile a script to produce a ScriptObjCode object
         * @returns object code pointer or null if compile error
         *          also can throw compile error exception
         */
        public ScriptObjCode Compile ()
        {
            bool oldObjFile = false;
            Stream objFileStream = null;
            StreamWriter asmFileWriter = null;
            string envar = null;
            string sourceHash = null;
            TextWriter saveSource = null;

            string asmFileName = GetScriptFileName (m_ScriptObjCodeKey + ".xmrasm");
            string lslFileName = GetScriptFileName (m_ScriptObjCodeKey + ".lsl");
            string objFileName = GetScriptFileName (m_ScriptObjCodeKey + ".xmrobj");
            string tmpFileName = GetScriptFileName (m_ScriptObjCodeKey + ".xmrtmp");

            /*
             * If we already have an object file, don't bother compiling.
             */
            if (!m_ForceRecomp && File.Exists (objFileName)) {
                objFileStream = File.OpenRead (objFileName);
                oldObjFile = true;
            } else {

                /*
                 * If source file empty, try to read from asset server.
                 */
                if (EmptySource (m_SourceCode)) {
                    m_SourceCode = FetchSource (m_CameFrom);
                }

                /*
                 * Maybe write script source to a file for debugging.
                 */
                envar = Environment.GetEnvironmentVariable ("MMRScriptCompileSaveSource");
                if ((envar != null) && ((envar[0] & 1) != 0)) {
                    m_log.Debug ("[XMREngine]: MMRScriptCompileSaveSource: saving to " + lslFileName);
                    saveSource = File.CreateText (lslFileName);
                }

                /*
                 * Parse source string into tokens.
                 */
                TokenBegin tokenBegin;
                try {
                    tokenBegin = TokenBegin.Construct(m_CameFrom, saveSource, ErrorHandler, m_SourceCode, out sourceHash);
                } finally {
                    if (saveSource != null) saveSource.Close ();
                }
                if (tokenBegin == null) {
                    m_log.Debug ("[XMREngine]: parsing errors on " + m_ScriptObjCodeKey);
                    return null;
                }

                /*
                 * Create object file one way or another.
                 */
                try {
                    objFileStream = File.Create (tmpFileName);

                    /*
                     * Create abstract syntax tree from raw tokens.
                     */
                    TokenScript tokenScript = ScriptReduce.Reduce(tokenBegin);
                    if (tokenScript == null) {
                        m_log.Warn ("[XMREngine]: reduction errors on " + m_ScriptObjCodeKey + " (" + m_CameFrom + ")");
                        PrintCompilerErrors ();
                        return null;
                    }

                    /*
                     * Compile abstract syntax tree to write object file.
                     */
                    BinaryWriter objFileWriter = new BinaryWriter (objFileStream);
                    bool ok = ScriptCodeGen.CodeGen(tokenScript, objFileWriter, sourceHash);
                    if (!ok) {
                        m_log.Warn ("[XMREngine]: compile error on " + m_ScriptObjCodeKey + " (" + m_CameFrom + ")");
                        PrintCompilerErrors ();
                        objFileStream.Close ();
                        return null;
                    }
                    objFileStream.Close ();

                    /*
                     * File has been completely written.
                     * If there is an old one laying around, delete it now.
                     * Then re-open the new file for reading from the beginning.
                     */
                    if (File.Exists (objFileName)) {
                        File.Replace (tmpFileName, objFileName, null);
                    } else {
                        File.Move (tmpFileName, objFileName);
                    }
                    objFileStream = File.OpenRead (objFileName);
                } finally {

                    /*
                     * In case something went wrong writing temp file, delete it.
                     */
                    try {
                        File.Delete (tmpFileName);
                    } catch {
                    }
                }

                /*
                 * Since we just wrote the .xmrobj file, maybe save disassembly.
                 */
                envar = Environment.GetEnvironmentVariable ("MMRScriptCompileSaveILGen");
                if ((envar != null) && ((envar[0] & 1) != 0)) {
                    m_log.Debug ("[XMREngine]: MMRScriptCompileSaveILGen: saving to " + asmFileName);
                    asmFileWriter = File.CreateText (asmFileName);
                }
            }

            /*
             * Read object file to create ScriptObjCode object.
             * Maybe also write disassembly to a file for debugging.
             */
            BinaryReader objFileReader = new BinaryReader (objFileStream);
            ScriptObjCode scriptObjCode = null;
            try {
                scriptObjCode = new ScriptObjCode (objFileReader, asmFileWriter, null);
                if (scriptObjCode != null) {
                    scriptObjCode.fileDateUtc = File.GetLastWriteTimeUtc (objFileName);
                }
            } finally {
                objFileReader.Close ();
                if (asmFileWriter != null) {
                    asmFileWriter.Flush ();
                    asmFileWriter.Close ();
                }
            }

            /*
             * Maybe an old object file has reached its expiration date.
             */
            if (oldObjFile && (scriptObjCode != null) && scriptObjCode.IsExpired ()) {
                m_log.Debug ("[XMREngine]: expiration reached on " + m_ScriptObjCodeKey + ", reloading");
                m_ForceRecomp = true;
                scriptObjCode = Compile ();
            }

            return scriptObjCode;
        }

        private void PrintCompilerErrors ()
        {
            m_log.Info ("[XMREngine]: - " + m_Part.GetWorldPosition () + " " + m_DescName);
            foreach (string error in m_CompilerErrors) {
                m_log.Info ("[XMREngine]: - " + error);
            }
        }

        /**
         * @brief Check for empty source, allowing for a first line of //... script engine selector.
         */
        public static bool EmptySource (string source)
        {
            int len = source.Length;
            bool skipeol = false;
            for (int i = 0; i < len; i ++) {
                char c = source[i];
                skipeol &= c != '\n';
                skipeol |= (c == '/') && (i + 1 < len) && (source[i+1] == '/');
                if ((c > ' ') && !skipeol) return false;
            }
            return true;
        }
    }
}