/*

 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.nashorn.internal.runtime;

import static jdk.nashorn.internal.codegen.CompilerConstants.CONSTANTS;

import static jdk.nashorn.internal.codegen.CompilerConstants.CREATE_PROGRAM_FUNCTION;

import static jdk.nashorn.internal.codegen.CompilerConstants.SOURCE;

import static jdk.nashorn.internal.codegen.CompilerConstants.STRICT_MODE;

import static jdk.nashorn.internal.runtime.CodeStore.newCodeStore;

import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;

import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

import static jdk.nashorn.internal.runtime.Source.sourceFor;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodType;

import java.lang.invoke.SwitchPoint;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.SoftReference;

import java.lang.reflect.Field;

import java.lang.reflect.Modifier;

import java.net.MalformedURLException;

import java.net.URL;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.CodeSigner;

import java.security.CodeSource;

import java.security.Permissions;

import java.security.PrivilegedAction;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.security.ProtectionDomain;

import java.util.Collection;

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.concurrent.atomic.AtomicLong;

import java.util.function.Consumer;

import java.util.function.Supplier;

import java.util.logging.Level;

import javax.script.ScriptEngine;

import jdk.internal.org.objectweb.asm.ClassReader;

import jdk.internal.org.objectweb.asm.util.CheckClassAdapter;

import jdk.nashorn.api.scripting.ClassFilter;

import jdk.nashorn.api.scripting.ScriptObjectMirror;

import jdk.nashorn.internal.codegen.Compiler;

import jdk.nashorn.internal.codegen.Compiler.CompilationPhases;

import jdk.nashorn.internal.codegen.ObjectClassGenerator;

import jdk.nashorn.internal.ir.FunctionNode;

import jdk.nashorn.internal.ir.debug.ASTWriter;

import jdk.nashorn.internal.ir.debug.PrintVisitor;

import jdk.nashorn.internal.lookup.MethodHandleFactory;

import jdk.nashorn.internal.objects.Global;

import jdk.nashorn.internal.parser.Parser;

import jdk.nashorn.internal.runtime.events.RuntimeEvent;

import jdk.nashorn.internal.runtime.logging.DebugLogger;

import jdk.nashorn.internal.runtime.logging.Loggable;

import jdk.nashorn.internal.runtime.logging.Logger;

import jdk.nashorn.internal.runtime.options.LoggingOption.LoggerInfo;

import jdk.nashorn.internal.runtime.options.Options;

/**

 * This class manages the global state of execution. Context is immutable.

 */

public final class Context {

    // nashorn specific security runtime access permission names

    /**

     * Permission needed to pass arbitrary nashorn command line options when creating Context.

     */

    public static final String NASHORN_SET_CONFIG      = "nashorn.setConfig";

    /**

     * Permission needed to create Nashorn Context instance.

     */

    public static final String NASHORN_CREATE_CONTEXT  = "nashorn.createContext";

    /**

     * Permission needed to create Nashorn Global instance.

     */

    public static final String NASHORN_CREATE_GLOBAL   = "nashorn.createGlobal";

    /**

     * Permission to get current Nashorn Context from thread local storage.

     */

    public static final String NASHORN_GET_CONTEXT     = "nashorn.getContext";

    /**

     * Permission to use Java reflection/jsr292 from script code.

     */

    public static final String NASHORN_JAVA_REFLECTION = "nashorn.JavaReflection";

    /**

     * Permission to enable nashorn debug mode.

     */

    public static final String NASHORN_DEBUG_MODE = "nashorn.debugMode";

    // nashorn load psuedo URL prefixes

    private static final String LOAD_CLASSPATH = "classpath:";

    private static final String LOAD_FX = "fx:";

    private static final String LOAD_NASHORN = "nashorn:";

    private static MethodHandles.Lookup LOOKUP = MethodHandles.lookup();

    private static MethodType CREATE_PROGRAM_FUNCTION_TYPE = MethodType.methodType(ScriptFunction.class, ScriptObject.class);

    /**

     * Keeps track of which builtin prototypes and properties have been relinked

     * Currently we are conservative and associate the name of a builtin class with all

     * its properties, so it's enough to invalidate a property to break all assumptions

     * about a prototype. This can be changed to a more fine grained approach, but no one

     * ever needs this, given the very rare occurance of swapping out only parts of

     * a builtin v.s. the entire builtin object

     */

    private final Map<String, SwitchPoint> builtinSwitchPoints = new HashMap<>();

    /* Force DebuggerSupport to be loaded. */

    static {

        DebuggerSupport.FORCELOAD = true;

    }

    /**

     * ContextCodeInstaller that has the privilege of installing classes in the Context.

     * Can only be instantiated from inside the context and is opaque to other classes

     */

    public static class ContextCodeInstaller implements CodeInstaller<ScriptEnvironment> {

        private final Context      context;

        private final ScriptLoader loader;

        private final CodeSource   codeSource;

        private ContextCodeInstaller(final Context context, final ScriptLoader loader, final CodeSource codeSource) {

            this.context    = context;

            this.loader     = loader;

            this.codeSource = codeSource;

        }

        /**

         * Return the context for this installer

         * @return ScriptEnvironment

         */

        @Override

        public ScriptEnvironment getOwner() {

            return context.env;

        }

        @Override

        public Class<?> install(final String className, final byte[] bytecode) {

            final String   binaryName = Compiler.binaryName(className);

            return loader.installClass(binaryName, bytecode, codeSource);

        }

        @Override

        public void initialize(final Collection<Class<?>> classes, final Source source, final Object[] constants) {

            try {

                AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {

                    @Override

                    public Void run() throws Exception {

                        for (final Class<?> clazz : classes) {

                            //use reflection to write source and constants table to installed classes

                            final Field sourceField = clazz.getDeclaredField(SOURCE.symbolName());

                            sourceField.setAccessible(true);

                            sourceField.set(null, source);

                            final Field constantsField = clazz.getDeclaredField(CONSTANTS.symbolName());

                            constantsField.setAccessible(true);

                            constantsField.set(null, constants);

                        }

                        return null;

                    }

                });

            } catch (final PrivilegedActionException e) {

                throw new RuntimeException(e);

            }

        }

        @Override

        public void verify(final byte[] code) {

            context.verify(code);

        }

        @Override

        public long getUniqueScriptId() {

            return context.getUniqueScriptId();

        }

        @Override

        public void storeScript(final String cacheKey, final Source source, final String mainClassName,

                                final Map<String,byte[]> classBytes, final Map<Integer, FunctionInitializer> initializers,

                                final Object[] constants, final int compilationId) {

            if (context.codeStore != null) {

                context.codeStore.store(cacheKey, source, mainClassName, classBytes, initializers, constants, compilationId);

            }

        }

        @Override

        public StoredScript loadScript(final Source source, final String functionKey) {

            if (context.codeStore != null) {

                return context.codeStore.load(source, functionKey);

            }

            return null;

        }

    }

    /** Is Context global debug mode enabled ? */

    public static final boolean DEBUG = Options.getBooleanProperty("nashorn.debug");

    private static final ThreadLocal<Global> currentGlobal = new ThreadLocal<>();

    // in-memory cache for loaded classes

    private ClassCache classCache;

    // persistent code store

    private CodeStore codeStore;

    /**

     * Get the current global scope

     * @return the current global scope

     */

    public static Global getGlobal() {

        // This class in a package.access protected package.

        // Trusted code only can call this method.

        return currentGlobal.get();

    }

    /**

     * Set the current global scope

     * @param global the global scope

     */

    public static void setGlobal(final ScriptObject global) {

        if (global != null && !(global instanceof Global)) {

            throw new IllegalArgumentException("not a global!");

        }

        setGlobal((Global)global);

    }

    /**

     * Set the current global scope

     * @param global the global scope

     */

    public static void setGlobal(final Global global) {

        // This class in a package.access protected package.

        // Trusted code only can call this method.

        assert getGlobal() != global;

        //same code can be cached between globals, then we need to invalidate method handle constants

        if (global != null) {

            Global.getConstants().invalidateAll();

        }

        currentGlobal.set(global);

    }

    /**

     * Get context of the current global

     * @return current global scope's context.

     */

    public static Context getContext() {

        final SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(new RuntimePermission(NASHORN_GET_CONTEXT));

        }

        return getContextTrusted();

    }

    /**

     * Get current context's error writer

     *

     * @return error writer of the current context

     */

    public static PrintWriter getCurrentErr() {

        final ScriptObject global = getGlobal();

        return (global != null)? global.getContext().getErr() : new PrintWriter(System.err);

    }

    /**

     * Output text to this Context's error stream

     * @param str text to write

     */

    public static void err(final String str) {

        err(str, true);

    }

    /**

     * Output text to this Context's error stream, optionally with

     * a newline afterwards

     *

     * @param str  text to write

     * @param crlf write a carriage return/new line after text

     */

    public static void err(final String str, final boolean crlf) {

        final PrintWriter err = Context.getCurrentErr();

        if (err != null) {

            if (crlf) {

                err.println(str);

            } else {

                err.print(str);

            }

        }

    }

    /** Current environment. */

    private final ScriptEnvironment env;

    /** is this context in strict mode? Cached from env. as this is used heavily. */

    final boolean _strict;

    /** class loader to resolve classes from script. */

    private final ClassLoader  appLoader;

    /** Class loader to load classes from -classpath option, if set. */

    private final ClassLoader  classPathLoader;

    /** Class loader to load classes compiled from scripts. */

    private final ScriptLoader scriptLoader;

    /** Current error manager. */

    private final ErrorManager errors;

    /** Unique id for script. Used only when --loader-per-compile=false */

    private final AtomicLong uniqueScriptId;

    /** Optional class filter to use for Java classes. Can be null. */

    private final ClassFilter classFilter;

    private static final ClassLoader myLoader = Context.class.getClassLoader();

    private static final StructureLoader sharedLoader;

    /*package-private*/ @SuppressWarnings("static-method")

    ClassLoader getSharedLoader() {

        return sharedLoader;

    }

    private static AccessControlContext createNoPermAccCtxt() {

        return new AccessControlContext(new ProtectionDomain[] { new ProtectionDomain(null, new Permissions()) });

    }

    private static AccessControlContext createPermAccCtxt(final String permName) {

        final Permissions perms = new Permissions();

        perms.add(new RuntimePermission(permName));

        return new AccessControlContext(new ProtectionDomain[] { new ProtectionDomain(null, perms) });

    }

    private static final AccessControlContext NO_PERMISSIONS_ACC_CTXT = createNoPermAccCtxt();

    private static final AccessControlContext CREATE_LOADER_ACC_CTXT  = createPermAccCtxt("createClassLoader");

    private static final AccessControlContext CREATE_GLOBAL_ACC_CTXT  = createPermAccCtxt(NASHORN_CREATE_GLOBAL);

    static {

        sharedLoader = AccessController.doPrivileged(new PrivilegedAction<StructureLoader>() {

            @Override

            public StructureLoader run() {

                return new StructureLoader(myLoader);

            }

        }, CREATE_LOADER_ACC_CTXT);

    }

    /**

     * ThrowErrorManager that throws ParserException upon error conditions.

     */

    public static class ThrowErrorManager extends ErrorManager {

        @Override

        public void error(final String message) {

            throw new ParserException(message);

        }

        @Override

        public void error(final ParserException e) {

            throw e;

        }

    }

    /**

     * Constructor

     *

     * @param options options from command line or Context creator

     * @param errors  error manger

     * @param appLoader application class loader

     */

    public Context(final Options options, final ErrorManager errors, final ClassLoader appLoader) {

        this(options, errors, appLoader, (ClassFilter)null);

    }

    /**

     * Constructor

     *

     * @param options options from command line or Context creator

     * @param errors  error manger

     * @param appLoader application class loader

     * @param classFilter class filter to use

     */

    public Context(final Options options, final ErrorManager errors, final ClassLoader appLoader, final ClassFilter classFilter) {

        this(options, errors, new PrintWriter(System.out, true), new PrintWriter(System.err, true), appLoader, classFilter);

    }

    /**

     * Constructor

     *

     * @param options options from command line or Context creator

     * @param errors  error manger

     * @param out     output writer for this Context

     * @param err     error writer for this Context

     * @param appLoader application class loader

     */

    public Context(final Options options, final ErrorManager errors, final PrintWriter out, final PrintWriter err, final ClassLoader appLoader) {

        this(options, errors, out, err, appLoader, (ClassFilter)null);

    }

    /**

     * Constructor

     *

     * @param options options from command line or Context creator

     * @param errors  error manger

     * @param out     output writer for this Context

     * @param err     error writer for this Context

     * @param appLoader application class loader

     * @param classFilter class filter to use

     */

    public Context(final Options options, final ErrorManager errors, final PrintWriter out, final PrintWriter err, final ClassLoader appLoader, final ClassFilter classFilter) {

        final SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(new RuntimePermission(NASHORN_CREATE_CONTEXT));

        }

        this.classFilter = classFilter;

        this.env       = new ScriptEnvironment(options, out, err);

        this._strict   = env._strict;

        this.appLoader = appLoader;

        if (env._loader_per_compile) {

            this.scriptLoader = null;

            this.uniqueScriptId = null;

        } else {

            this.scriptLoader = createNewLoader();

            this.uniqueScriptId = new AtomicLong();

        }

        this.errors    = errors;

        // if user passed -classpath option, make a class loader with that and set it as

        // thread context class loader so that script can access classes from that path.

        final String classPath = options.getString("classpath");

        if (!env._compile_only && classPath != null && !classPath.isEmpty()) {

            // make sure that caller can create a class loader.

            if (sm != null) {

                sm.checkPermission(new RuntimePermission("createClassLoader"));

            }

            this.classPathLoader = NashornLoader.createClassLoader(classPath);

        } else {

            this.classPathLoader = null;

        }

        final int cacheSize = env._class_cache_size;

        if (cacheSize > 0) {

            classCache = new ClassCache(cacheSize);

        }

        if (env._persistent_cache) {

            try {

                codeStore = newCodeStore(this);

            } catch (final IOException e) {

                throw new RuntimeException("Error initializing code cache", e);

            }

        }

        // print version info if asked.

        if (env._version) {

            getErr().println("nashorn " + Version.version());

        }

        if (env._fullversion) {

            getErr().println("nashorn full version " + Version.fullVersion());

        }

        initLoggers();

    }