src/jdk/nashorn/internal/runtime/Context.java

Fri, 13 Sep 2013 16:45:11 +0530

author
sundar
date
Fri, 13 Sep 2013 16:45:11 +0530
changeset 552
8b0914b25430
parent 541
c3b6ce7b74bf
child 587
7272ec90f2c6
permissions
-rw-r--r--

8024619: JDBC java.sql.DriverManager is not usable from JS script
Reviewed-by: jlaskey, lagergren, attila

     1 /*
     2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.  Oracle designates this
     8  * particular file as subject to the "Classpath" exception as provided
     9  * by Oracle in the LICENSE file that accompanied this code.
    10  *
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    14  * version 2 for more details (a copy is included in the LICENSE file that
    15  * accompanied this code).
    16  *
    17  * You should have received a copy of the GNU General Public License version
    18  * 2 along with this work; if not, write to the Free Software Foundation,
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    20  *
    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    22  * or visit www.oracle.com if you need additional information or have any
    23  * questions.
    24  */
    26 package jdk.nashorn.internal.runtime;
    28 import static jdk.nashorn.internal.codegen.CompilerConstants.RUN_SCRIPT;
    29 import static jdk.nashorn.internal.codegen.CompilerConstants.STRICT_MODE;
    30 import static jdk.nashorn.internal.lookup.Lookup.MH;
    31 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
    32 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
    34 import java.io.File;
    35 import java.io.IOException;
    36 import java.io.PrintWriter;
    37 import java.lang.invoke.MethodHandle;
    38 import java.lang.invoke.MethodHandles;
    39 import java.lang.reflect.Modifier;
    40 import java.util.concurrent.atomic.AtomicLong;
    41 import java.net.MalformedURLException;
    42 import java.net.URL;
    43 import java.security.AccessControlContext;
    44 import java.security.AccessController;
    45 import java.security.CodeSigner;
    46 import java.security.CodeSource;
    47 import java.security.Permissions;
    48 import java.security.PrivilegedAction;
    49 import java.security.ProtectionDomain;
    50 import java.util.Map;
    52 import jdk.internal.org.objectweb.asm.ClassReader;
    53 import jdk.internal.org.objectweb.asm.util.CheckClassAdapter;
    54 import jdk.nashorn.api.scripting.ScriptObjectMirror;
    55 import jdk.nashorn.internal.codegen.Compiler;
    56 import jdk.nashorn.internal.codegen.ObjectClassGenerator;
    57 import jdk.nashorn.internal.ir.FunctionNode;
    58 import jdk.nashorn.internal.ir.debug.ASTWriter;
    59 import jdk.nashorn.internal.ir.debug.PrintVisitor;
    60 import jdk.nashorn.internal.objects.Global;
    61 import jdk.nashorn.internal.parser.Parser;
    62 import jdk.nashorn.internal.runtime.options.Options;
    64 /**
    65  * This class manages the global state of execution. Context is immutable.
    66  */
    67 public final class Context {
    68     // nashorn specific security runtime access permission names
    69     /**
    70      * Permission needed to pass arbitrary nashorn command line options when creating Context.
    71      */
    72     public static final String NASHORN_SET_CONFIG      = "nashorn.setConfig";
    74     /**
    75      * Permission needed to create Nashorn Context instance.
    76      */
    77     public static final String NASHORN_CREATE_CONTEXT  = "nashorn.createContext";
    79     /**
    80      * Permission needed to create Nashorn Global instance.
    81      */
    82     public static final String NASHORN_CREATE_GLOBAL   = "nashorn.createGlobal";
    84     /**
    85      * Permission to get current Nashorn Context from thread local storage.
    86      */
    87     public static final String NASHORN_GET_CONTEXT     = "nashorn.getContext";
    89     /**
    90      * Permission to use Java reflection/jsr292 from script code.
    91      */
    92     public static final String NASHORN_JAVA_REFLECTION = "nashorn.JavaReflection";
    94     /* Force DebuggerSupport to be loaded. */
    95     static {
    96         DebuggerSupport.FORCELOAD = true;
    97     }
    99     /**
   100      * ContextCodeInstaller that has the privilege of installing classes in the Context.
   101      * Can only be instantiated from inside the context and is opaque to other classes
   102      */
   103     public static class ContextCodeInstaller implements CodeInstaller<ScriptEnvironment> {
   104         private final Context      context;
   105         private final ScriptLoader loader;
   106         private final CodeSource   codeSource;
   108         private ContextCodeInstaller(final Context context, final ScriptLoader loader, final CodeSource codeSource) {
   109             this.context    = context;
   110             this.loader     = loader;
   111             this.codeSource = codeSource;
   112         }
   114         /**
   115          * Return the context for this installer
   116          * @return ScriptEnvironment
   117          */
   118         @Override
   119         public ScriptEnvironment getOwner() {
   120             return context.env;
   121         }
   123         @Override
   124         public Class<?> install(final String className, final byte[] bytecode) {
   125             return loader.installClass(className, bytecode, codeSource);
   126         }
   128         @Override
   129         public void verify(final byte[] code) {
   130             context.verify(code);
   131         }
   133         @Override
   134         public long getUniqueScriptId() {
   135             return context.getUniqueScriptId();
   136         }
   137     }
   139     /** Is Context global debug mode enabled ? */
   140     public static final boolean DEBUG = Options.getBooleanProperty("nashorn.debug");
   142     private static final ThreadLocal<ScriptObject> currentGlobal = new ThreadLocal<>();
   144     /**
   145      * Get the current global scope
   146      * @return the current global scope
   147      */
   148     public static ScriptObject getGlobal() {
   149         // This class in a package.access protected package.
   150         // Trusted code only can call this method.
   151         return getGlobalTrusted();
   152     }
   154     /**
   155      * Set the current global scope
   156      * @param global the global scope
   157      */
   158     public static void setGlobal(final ScriptObject global) {
   159         if (global != null && !(global instanceof Global)) {
   160             throw new IllegalArgumentException("global is not an instance of Global!");
   161         }
   163         setGlobalTrusted(global);
   164     }
   166     /**
   167      * Get context of the current global
   168      * @return current global scope's context.
   169      */
   170     public static Context getContext() {
   171         final SecurityManager sm = System.getSecurityManager();
   172         if (sm != null) {
   173             sm.checkPermission(new RuntimePermission(NASHORN_GET_CONTEXT));
   174         }
   175         return getContextTrusted();
   176     }
   178     /**
   179      * Get current context's error writer
   180      *
   181      * @return error writer of the current context
   182      */
   183     public static PrintWriter getCurrentErr() {
   184         final ScriptObject global = getGlobalTrusted();
   185         return (global != null)? global.getContext().getErr() : new PrintWriter(System.err);
   186     }
   188     /**
   189      * Output text to this Context's error stream
   190      * @param str text to write
   191      */
   192     public static void err(final String str) {
   193         err(str, true);
   194     }
   196     /**
   197      * Output text to this Context's error stream, optionally with
   198      * a newline afterwards
   199      *
   200      * @param str  text to write
   201      * @param crlf write a carriage return/new line after text
   202      */
   203     @SuppressWarnings("resource")
   204     public static void err(final String str, final boolean crlf) {
   205         final PrintWriter err = Context.getCurrentErr();
   206         if (err != null) {
   207             if (crlf) {
   208                 err.println(str);
   209             } else {
   210                 err.print(str);
   211             }
   212         }
   213     }
   215     /** Current environment. */
   216     private final ScriptEnvironment env;
   218     /** is this context in strict mode? Cached from env. as this is used heavily. */
   219     final boolean _strict;
   221     /** class loader to resolve classes from script. */
   222     private final ClassLoader  appLoader;
   224     /** Class loader to load classes from -classpath option, if set. */
   225     private final ClassLoader  classPathLoader;
   227     /** Class loader to load classes compiled from scripts. */
   228     private final ScriptLoader scriptLoader;
   230     /** Current error manager. */
   231     private final ErrorManager errors;
   233     /** Unique id for script. Used only when --loader-per-compile=false */
   234     private final AtomicLong uniqueScriptId;
   236     private static final ClassLoader myLoader = Context.class.getClassLoader();
   237     private static final StructureLoader sharedLoader;
   239     /*package-private*/ ClassLoader getSharedLoader() {
   240         return sharedLoader;
   241     }
   243     private static AccessControlContext createNoPermAccCtxt() {
   244         return new AccessControlContext(new ProtectionDomain[] { new ProtectionDomain(null, new Permissions()) });
   245     }
   247     private static AccessControlContext createPermAccCtxt(final String permName) {
   248         final Permissions perms = new Permissions();
   249         perms.add(new RuntimePermission(permName));
   250         return new AccessControlContext(new ProtectionDomain[] { new ProtectionDomain(null, perms) });
   251     }
   253     private static final AccessControlContext NO_PERMISSIONS_ACC_CTXT = createNoPermAccCtxt();
   254     private static final AccessControlContext CREATE_LOADER_ACC_CTXT  = createPermAccCtxt("createClassLoader");
   255     private static final AccessControlContext CREATE_GLOBAL_ACC_CTXT  = createPermAccCtxt(NASHORN_CREATE_GLOBAL);
   257     static {
   258         sharedLoader = AccessController.doPrivileged(new PrivilegedAction<StructureLoader>() {
   259             @Override
   260             public StructureLoader run() {
   261                 return new StructureLoader(myLoader);
   262             }
   263         }, CREATE_LOADER_ACC_CTXT);
   264     }
   266     /**
   267      * ThrowErrorManager that throws ParserException upon error conditions.
   268      */
   269     public static class ThrowErrorManager extends ErrorManager {
   270         @Override
   271         public void error(final String message) {
   272             throw new ParserException(message);
   273         }
   275         @Override
   276         public void error(final ParserException e) {
   277             throw e;
   278         }
   279     }
   281     /**
   282      * Constructor
   283      *
   284      * @param options options from command line or Context creator
   285      * @param errors  error manger
   286      * @param appLoader application class loader
   287      */
   288     public Context(final Options options, final ErrorManager errors, final ClassLoader appLoader) {
   289         this(options, errors, new PrintWriter(System.out, true), new PrintWriter(System.err, true), appLoader);
   290     }
   292     /**
   293      * Constructor
   294      *
   295      * @param options options from command line or Context creator
   296      * @param errors  error manger
   297      * @param out     output writer for this Context
   298      * @param err     error writer for this Context
   299      * @param appLoader application class loader
   300      */
   301     public Context(final Options options, final ErrorManager errors, final PrintWriter out, final PrintWriter err, final ClassLoader appLoader) {
   302         final SecurityManager sm = System.getSecurityManager();
   303         if (sm != null) {
   304             sm.checkPermission(new RuntimePermission(NASHORN_CREATE_CONTEXT));
   305         }
   307         this.env       = new ScriptEnvironment(options, out, err);
   308         this._strict   = env._strict;
   309         this.appLoader = appLoader;
   310         if (env._loader_per_compile) {
   311             this.scriptLoader = null;
   312             this.uniqueScriptId = null;
   313         } else {
   314             this.scriptLoader = createNewLoader();
   315             this.uniqueScriptId = new AtomicLong();
   316         }
   317         this.errors    = errors;
   319         // if user passed -classpath option, make a class loader with that and set it as
   320         // thread context class loader so that script can access classes from that path.
   321         final String classPath = options.getString("classpath");
   322         if (! env._compile_only && classPath != null && !classPath.isEmpty()) {
   323             // make sure that caller can create a class loader.
   324             if (sm != null) {
   325                 sm.checkPermission(new RuntimePermission("createClassLoader"));
   326             }
   327             this.classPathLoader = NashornLoader.createClassLoader(classPath);
   328         } else {
   329             this.classPathLoader = null;
   330         }
   332         // print version info if asked.
   333         if (env._version) {
   334             getErr().println("nashorn " + Version.version());
   335         }
   337         if (env._fullversion) {
   338             getErr().println("nashorn full version " + Version.fullVersion());
   339         }
   340     }
   342     /**
   343      * Get the error manager for this context
   344      * @return error manger
   345      */
   346     public ErrorManager getErrorManager() {
   347         return errors;
   348     }
   350     /**
   351      * Get the script environment for this context
   352      * @return script environment
   353      */
   354     public ScriptEnvironment getEnv() {
   355         return env;
   356     }
   358     /**
   359      * Get the output stream for this context
   360      * @return output print writer
   361      */
   362     public PrintWriter getOut() {
   363         return env.getOut();
   364     }
   366     /**
   367      * Get the error stream for this context
   368      * @return error print writer
   369      */
   370     public PrintWriter getErr() {
   371         return env.getErr();
   372     }
   374     /**
   375      * Get the PropertyMap of the current global scope
   376      * @return the property map of the current global scope
   377      */
   378     public static PropertyMap getGlobalMap() {
   379         return Context.getGlobalTrusted().getMap();
   380     }
   382     /**
   383      * Compile a top level script.
   384      *
   385      * @param source the source
   386      * @param scope  the scope
   387      *
   388      * @return top level function for script
   389      */
   390     public ScriptFunction compileScript(final Source source, final ScriptObject scope) {
   391         return compileScript(source, scope, this.errors);
   392     }
   394     /**
   395      * Entry point for {@code eval}
   396      *
   397      * @param initialScope The scope of this eval call
   398      * @param string       Evaluated code as a String
   399      * @param callThis     "this" to be passed to the evaluated code
   400      * @param location     location of the eval call
   401      * @param strict       is this {@code eval} call from a strict mode code?
   402      *
   403      * @return the return value of the {@code eval}
   404      */
   405     public Object eval(final ScriptObject initialScope, final String string, final Object callThis, final Object location, final boolean strict) {
   406         final String  file       = (location == UNDEFINED || location == null) ? "<eval>" : location.toString();
   407         final Source  source     = new Source(file, string);
   408         final boolean directEval = location != UNDEFINED; // is this direct 'eval' call or indirectly invoked eval?
   409         final ScriptObject global = Context.getGlobalTrusted();
   411         ScriptObject scope = initialScope;
   413         // ECMA section 10.1.1 point 2 says eval code is strict if it begins
   414         // with "use strict" directive or eval direct call itself is made
   415         // from from strict mode code. We are passed with caller's strict mode.
   416         boolean strictFlag = directEval && strict;
   418         Class<?> clazz = null;
   419         try {
   420             clazz = compile(source, new ThrowErrorManager(), strictFlag);
   421         } catch (final ParserException e) {
   422             e.throwAsEcmaException(global);
   423             return null;
   424         }
   426         if (!strictFlag) {
   427             // We need to get strict mode flag from compiled class. This is
   428             // because eval code may start with "use strict" directive.
   429             try {
   430                 strictFlag = clazz.getField(STRICT_MODE.symbolName()).getBoolean(null);
   431             } catch (final NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
   432                 //ignored
   433                 strictFlag = false;
   434             }
   435         }
   437         // In strict mode, eval does not instantiate variables and functions
   438         // in the caller's environment. A new environment is created!
   439         if (strictFlag) {
   440             // Create a new scope object
   441             final ScriptObject strictEvalScope = ((GlobalObject)global).newObject();
   443             // bless it as a "scope"
   444             strictEvalScope.setIsScope();
   446             // set given scope to be it's proto so that eval can still
   447             // access caller environment vars in the new environment.
   448             strictEvalScope.setProto(scope);
   449             scope = strictEvalScope;
   450         }
   452         ScriptFunction func = getRunScriptFunction(clazz, scope);
   453         Object evalThis;
   454         if (directEval) {
   455             evalThis = (callThis instanceof ScriptObject || strictFlag) ? callThis : global;
   456         } else {
   457             evalThis = global;
   458         }
   460         return ScriptRuntime.apply(func, evalThis);
   461     }
   463     private static Source loadInternal(final String srcStr, final String prefix, final String resourcePath) {
   464         if (srcStr.startsWith(prefix)) {
   465             final String resource = resourcePath + srcStr.substring(prefix.length());
   466             // NOTE: even sandbox scripts should be able to load scripts in nashorn: scheme
   467             // These scripts are always available and are loaded from nashorn.jar's resources.
   468             return AccessController.doPrivileged(
   469                     new PrivilegedAction<Source>() {
   470                         @Override
   471                         public Source run() {
   472                             try {
   473                                 final URL resURL = Context.class.getResource(resource);
   474                                 return (resURL != null)? new Source(srcStr, resURL) : null;
   475                             } catch (final IOException exp) {
   476                                 return null;
   477                             }
   478                         }
   479                     });
   480         }
   482         return null;
   483     }
   485     /**
   486      * Implementation of {@code load} Nashorn extension. Load a script file from a source
   487      * expression
   488      *
   489      * @param scope  the scope
   490      * @param from   source expression for script
   491      *
   492      * @return return value for load call (undefined)
   493      *
   494      * @throws IOException if source cannot be found or loaded
   495      */
   496     public Object load(final ScriptObject scope, final Object from) throws IOException {
   497         final Object src = (from instanceof ConsString)?  from.toString() : from;
   498         Source source = null;
   500         // load accepts a String (which could be a URL or a file name), a File, a URL
   501         // or a ScriptObject that has "name" and "source" (string valued) properties.
   502         if (src instanceof String) {
   503             final String srcStr = (String)src;
   504             final File file = new File(srcStr);
   505             if (srcStr.indexOf(':') != -1) {
   506                 if ((source = loadInternal(srcStr, "nashorn:", "resources/")) == null &&
   507                     (source = loadInternal(srcStr, "fx:", "resources/fx/")) == null) {
   508                     URL url;
   509                     try {
   510                         //check for malformed url. if malformed, it may still be a valid file
   511                         url = new URL(srcStr);
   512                     } catch (final MalformedURLException e) {
   513                         url = file.toURI().toURL();
   514                     }
   515                     source = new Source(url.toString(), url);
   516                 }
   517             } else if (file.isFile()) {
   518                 source = new Source(srcStr, file);
   519             }
   520         } else if (src instanceof File && ((File)src).isFile()) {
   521             final File file = (File)src;
   522             source = new Source(file.getName(), file);
   523         } else if (src instanceof URL) {
   524             final URL url = (URL)src;
   525             source = new Source(url.toString(), url);
   526         } else if (src instanceof ScriptObject) {
   527             final ScriptObject sobj = (ScriptObject)src;
   528             if (sobj.has("script") && sobj.has("name")) {
   529                 final String script = JSType.toString(sobj.get("script"));
   530                 final String name   = JSType.toString(sobj.get("name"));
   531                 source = new Source(name, script);
   532             }
   533         } else if (src instanceof Map) {
   534             final Map<?,?> map = (Map<?,?>)src;
   535             if (map.containsKey("script") && map.containsKey("name")) {
   536                 final String script = JSType.toString(map.get("script"));
   537                 final String name   = JSType.toString(map.get("name"));
   538                 source = new Source(name, script);
   539             }
   540         }
   542         if (source != null) {
   543             return evaluateSource(source, scope, scope);
   544         }
   546         throw typeError("cant.load.script", ScriptRuntime.safeToString(from));
   547     }
   549     /**
   550      * Implementation of {@code loadWithNewGlobal} Nashorn extension. Load a script file from a source
   551      * expression, after creating a new global scope.
   552      *
   553      * @param from source expression for script
   554      * @param args (optional) arguments to be passed to the loaded script
   555      *
   556      * @return return value for load call (undefined)
   557      *
   558      * @throws IOException if source cannot be found or loaded
   559      */
   560     public Object loadWithNewGlobal(final Object from, final Object...args) throws IOException {
   561         final ScriptObject oldGlobal = getGlobalTrusted();
   562         final ScriptObject newGlobal = AccessController.doPrivileged(new PrivilegedAction<ScriptObject>() {
   563            @Override
   564            public ScriptObject run() {
   565                try {
   566                    return newGlobal();
   567                } catch (final RuntimeException e) {
   568                    if (Context.DEBUG) {
   569                        e.printStackTrace();
   570                    }
   571                    throw e;
   572                }
   573            }
   574         }, CREATE_GLOBAL_ACC_CTXT);
   575         // initialize newly created Global instance
   576         initGlobal(newGlobal);
   577         setGlobalTrusted(newGlobal);
   579         final Object[] wrapped = args == null? ScriptRuntime.EMPTY_ARRAY :  ScriptObjectMirror.wrapArray(args, oldGlobal);
   580         newGlobal.put("arguments", ((GlobalObject)newGlobal).wrapAsObject(wrapped), env._strict);
   582         try {
   583             // wrap objects from newGlobal's world as mirrors - but if result
   584             // is from oldGlobal's world, unwrap it!
   585             return ScriptObjectMirror.unwrap(ScriptObjectMirror.wrap(load(newGlobal, from), newGlobal), oldGlobal);
   586         } finally {
   587             setGlobalTrusted(oldGlobal);
   588         }
   589     }
   591     /**
   592      * Load or get a structure class. Structure class names are based on the number of parameter fields
   593      * and {@link AccessorProperty} fields in them. Structure classes are used to represent ScriptObjects
   594      *
   595      * @see ObjectClassGenerator
   596      * @see AccessorProperty
   597      * @see ScriptObject
   598      *
   599      * @param fullName  full name of class, e.g. jdk.nashorn.internal.objects.JO2P1 contains 2 fields and 1 parameter.
   600      *
   601      * @return the {@code Class<?>} for this structure
   602      *
   603      * @throws ClassNotFoundException if structure class cannot be resolved
   604      */
   605     public static Class<?> forStructureClass(final String fullName) throws ClassNotFoundException {
   606         if (System.getSecurityManager() != null && !StructureLoader.isStructureClass(fullName)) {
   607             throw new ClassNotFoundException(fullName);
   608         }
   609         return Class.forName(fullName, true, sharedLoader);
   610     }
   612     /**
   613      * Checks that the given package can be accessed from no permissions context.
   614      *
   615      * @param fullName fully qualified package name
   616      * @throw SecurityException if not accessible
   617      */
   618     public static void checkPackageAccess(final String fullName) {
   619         final int index = fullName.lastIndexOf('.');
   620         if (index != -1) {
   621             final SecurityManager sm = System.getSecurityManager();
   622             if (sm != null) {
   623                 AccessController.doPrivileged(new PrivilegedAction<Void>() {
   624                     @Override
   625                     public Void run() {
   626                         sm.checkPackageAccess(fullName.substring(0, index));
   627                         return null;
   628                     }
   629                 }, NO_PERMISSIONS_ACC_CTXT);
   630             }
   631         }
   632     }
   634     /**
   635      * Checks that the given package can be accessed from no permissions context.
   636      *
   637      * @param fullName fully qualified package name
   638      * @return true if package is accessible, false otherwise
   639      */
   640     public static boolean isAccessiblePackage(final String fullName) {
   641         try {
   642             checkPackageAccess(fullName);
   643             return true;
   644         } catch (final SecurityException se) {
   645             return false;
   646         }
   647     }
   649     /**
   650      * Checks that the given Class is public and it can be accessed from no permissions context.
   651      *
   652      * @param clazz Class object to check
   653      * @return true if Class is accessible, false otherwise
   654      */
   655     public static boolean isAccessibleClass(final Class<?> clazz) {
   656         return Modifier.isPublic(clazz.getModifiers()) && Context.isAccessiblePackage(clazz.getName());
   657     }
   659     /**
   660      * Lookup a Java class. This is used for JSR-223 stuff linking in from
   661      * {@code jdk.nashorn.internal.objects.NativeJava} and {@code jdk.nashorn.internal.runtime.NativeJavaPackage}
   662      *
   663      * @param fullName full name of class to load
   664      *
   665      * @return the {@code Class<?>} for the name
   666      *
   667      * @throws ClassNotFoundException if class cannot be resolved
   668      */
   669     public Class<?> findClass(final String fullName) throws ClassNotFoundException {
   670         // check package access as soon as possible!
   671         checkPackageAccess(fullName);
   673         // try the script -classpath loader, if that is set
   674         if (classPathLoader != null) {
   675             try {
   676                 return Class.forName(fullName, true, classPathLoader);
   677             } catch (final ClassNotFoundException ignored) {
   678                 // ignore, continue search
   679             }
   680         }
   682         // Try finding using the "app" loader.
   683         return Class.forName(fullName, true, appLoader);
   684     }
   686     /**
   687      * Hook to print stack trace for a {@link Throwable} that occurred during
   688      * execution
   689      *
   690      * @param t throwable for which to dump stack
   691      */
   692     public static void printStackTrace(final Throwable t) {
   693         if (Context.DEBUG) {
   694             t.printStackTrace(Context.getCurrentErr());
   695         }
   696     }
   698     /**
   699      * Verify generated bytecode before emission. This is called back from the
   700      * {@link ObjectClassGenerator} or the {@link Compiler}. If the "--verify-code" parameter
   701      * hasn't been given, this is a nop
   702      *
   703      * Note that verification may load classes -- we don't want to do that unless
   704      * user specified verify option. We check it here even though caller
   705      * may have already checked that flag
   706      *
   707      * @param bytecode bytecode to verify
   708      */
   709     public void verify(final byte[] bytecode) {
   710         if (env._verify_code) {
   711             // No verification when security manager is around as verifier
   712             // may load further classes - which should be avoided.
   713             if (System.getSecurityManager() == null) {
   714                 CheckClassAdapter.verify(new ClassReader(bytecode), sharedLoader, false, new PrintWriter(System.err, true));
   715             }
   716         }
   717     }
   719     /**
   720      * Create and initialize a new global scope object.
   721      *
   722      * @return the initialized global scope object.
   723      */
   724     public ScriptObject createGlobal() {
   725         return initGlobal(newGlobal());
   726     }
   728     /**
   729      * Create a new uninitialized global scope object
   730      * @return the global script object
   731      */
   732     public ScriptObject newGlobal() {
   733         return new Global(this);
   734     }
   736     /**
   737      * Initialize given global scope object.
   738      *
   739      * @param global the global
   740      * @return the initialized global scope object.
   741      */
   742     public ScriptObject initGlobal(final ScriptObject global) {
   743         if (! (global instanceof GlobalObject)) {
   744             throw new IllegalArgumentException("not a global object!");
   745         }
   747         // Need only minimal global object, if we are just compiling.
   748         if (!env._compile_only) {
   749             final ScriptObject oldGlobal = Context.getGlobalTrusted();
   750             try {
   751                 Context.setGlobalTrusted(global);
   752                 // initialize global scope with builtin global objects
   753                 ((GlobalObject)global).initBuiltinObjects();
   754             } finally {
   755                 Context.setGlobalTrusted(oldGlobal);
   756             }
   757         }
   759         return global;
   760     }
   762     /**
   763      * Trusted variants - package-private
   764      */
   766     /**
   767      * Return the current global scope
   768      * @return current global scope
   769      */
   770     static ScriptObject getGlobalTrusted() {
   771         return currentGlobal.get();
   772     }
   774     /**
   775      * Set the current global scope
   776      */
   777     static void setGlobalTrusted(ScriptObject global) {
   778          currentGlobal.set(global);
   779     }
   781     /**
   782      * Return the current global's context
   783      * @return current global's context
   784      */
   785     static Context getContextTrusted() {
   786         return Context.getGlobalTrusted().getContext();
   787     }
   789     /**
   790      * Try to infer Context instance from the Class. If we cannot,
   791      * then get it from the thread local variable.
   792      *
   793      * @param clazz the class
   794      * @return context
   795      */
   796     static Context fromClass(final Class<?> clazz) {
   797         final ClassLoader loader = clazz.getClassLoader();
   799         if (loader instanceof ScriptLoader) {
   800             return ((ScriptLoader)loader).getContext();
   801         }
   803         return Context.getContextTrusted();
   804     }
   806     private Object evaluateSource(final Source source, final ScriptObject scope, final ScriptObject thiz) {
   807         ScriptFunction script = null;
   809         try {
   810             script = compileScript(source, scope, new Context.ThrowErrorManager());
   811         } catch (final ParserException e) {
   812             e.throwAsEcmaException();
   813         }
   815         return ScriptRuntime.apply(script, thiz);
   816     }
   818     private static ScriptFunction getRunScriptFunction(final Class<?> script, final ScriptObject scope) {
   819         if (script == null) {
   820             return null;
   821         }
   823         // Get run method - the entry point to the script
   824         final MethodHandle runMethodHandle =
   825                 MH.findStatic(
   826                     MethodHandles.lookup(),
   827                     script,
   828                     RUN_SCRIPT.symbolName(),
   829                     MH.type(
   830                         Object.class,
   831                         ScriptFunction.class,
   832                         Object.class));
   834         boolean strict;
   836         try {
   837             strict = script.getField(STRICT_MODE.symbolName()).getBoolean(null);
   838         } catch (final NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
   839             strict = false;
   840         }
   842         // Package as a JavaScript function and pass function back to shell.
   843         return ((GlobalObject)Context.getGlobalTrusted()).newScriptFunction(RUN_SCRIPT.symbolName(), runMethodHandle, scope, strict);
   844     }
   846     private ScriptFunction compileScript(final Source source, final ScriptObject scope, final ErrorManager errMan) {
   847         return getRunScriptFunction(compile(source, errMan, this._strict), scope);
   848     }
   850     private synchronized Class<?> compile(final Source source, final ErrorManager errMan, final boolean strict) {
   851         // start with no errors, no warnings.
   852         errMan.reset();
   854         GlobalObject global = null;
   855         Class<?> script;
   857         if (env._class_cache_size > 0) {
   858             global = (GlobalObject)Context.getGlobalTrusted();
   859             script = global.findCachedClass(source);
   860             if (script != null) {
   861                 Compiler.LOG.fine("Code cache hit for ", source, " avoiding recompile.");
   862                 return script;
   863             }
   864         }
   866         final FunctionNode functionNode = new Parser(env, source, errMan, strict).parse();
   867         if (errors.hasErrors()) {
   868             return null;
   869         }
   871         if (env._print_ast) {
   872             getErr().println(new ASTWriter(functionNode));
   873         }
   875         if (env._print_parse) {
   876             getErr().println(new PrintVisitor(functionNode));
   877         }
   879         if (env._parse_only) {
   880             return null;
   881         }
   883         final URL          url    = source.getURL();
   884         final ScriptLoader loader = env._loader_per_compile ? createNewLoader() : scriptLoader;
   885         final CodeSource   cs     = url == null ? null : new CodeSource(url, (CodeSigner[])null);
   886         final CodeInstaller<ScriptEnvironment> installer = new ContextCodeInstaller(this, loader, cs);
   888         final Compiler compiler = new Compiler(installer, strict);
   890         final FunctionNode newFunctionNode = compiler.compile(functionNode);
   891         script = compiler.install(newFunctionNode);
   893         if (global != null) {
   894             global.cacheClass(source, script);
   895         }
   897         return script;
   898     }
   900     private ScriptLoader createNewLoader() {
   901         return AccessController.doPrivileged(
   902              new PrivilegedAction<ScriptLoader>() {
   903                 @Override
   904                 public ScriptLoader run() {
   905                     return new ScriptLoader(appLoader, Context.this);
   906                 }
   907              }, CREATE_LOADER_ACC_CTXT);
   908     }
   910     private long getUniqueScriptId() {
   911         return uniqueScriptId.getAndIncrement();
   912     }
   913 }

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