/*
 * Copyright (c) 1999, 2016, 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 com.sun.tools.javac.code;

import java.io.IOException;
import java.nio.file.Path;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;

import javax.lang.model.SourceVersion;
import javax.tools.JavaFileManager;
import javax.tools.JavaFileManager.Location;
import javax.tools.JavaFileObject;
import javax.tools.JavaFileObject.Kind;
import javax.tools.StandardJavaFileManager;
import javax.tools.StandardLocation;

import com.sun.tools.javac.code.Scope.WriteableScope;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.Completer;
import com.sun.tools.javac.code.Symbol.CompletionFailure;
import com.sun.tools.javac.code.Symbol.ModuleSymbol;
import com.sun.tools.javac.code.Symbol.PackageSymbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.comp.Annotate;
import com.sun.tools.javac.file.JRTIndex;
import com.sun.tools.javac.file.JavacFileManager;
import com.sun.tools.javac.jvm.ClassReader;
import com.sun.tools.javac.jvm.Profile;
import com.sun.tools.javac.main.Option;
import com.sun.tools.javac.platform.PlatformDescription;
import com.sun.tools.javac.util.*;

import static javax.tools.StandardLocation.*;

import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Kinds.Kind.*;

import com.sun.tools.javac.util.Dependencies.CompletionCause;

 This class provides operations to locate class definitions
 from the source and class files on the paths provided to javac.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 *  This class provides operations to locate class definitions
 *  from the source and class files on the paths provided to javac.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class ClassFinder {
    
The context key for the class finder. /** The context key for the class finder. */
    protected static final Context.Key<ClassFinder> classFinderKey = new Context.Key<>();

    ClassReader reader;

    private final Annotate annotate;

    
Switch: verbose output.
/** Switch: verbose output.
     */
    boolean verbose;

    
Switch: cache completion failures unless -XDdev is used
/**
     * Switch: cache completion failures unless -XDdev is used
     */
    private boolean cacheCompletionFailure;

    
Switch: prefer source files instead of newer when both source
and class are available
/**
     * Switch: prefer source files instead of newer when both source
     * and class are available
     **/
    protected boolean preferSource;

    
Switch: Search classpath and sourcepath for classes before the
bootclasspath
/**
     * Switch: Search classpath and sourcepath for classes before the
     * bootclasspath
     */
    protected boolean userPathsFirst;

    
Switch: should read OTHER classfiles (.sig files) from PLATFORM_CLASS_PATH.
/**
     * Switch: should read OTHER classfiles (.sig files) from PLATFORM_CLASS_PATH.
     */
    private boolean allowSigFiles;

    
The log to use for verbose output
/** The log to use for verbose output
     */
    final Log log;

    
The symbol table. /** The symbol table. */
    Symtab syms;

    
The name table. /** The name table. */
    final Names names;

    
Force a completion failure on this name
/** Force a completion failure on this name
     */
    final Name completionFailureName;

    
Access to files
/** Access to files
     */
    private final JavaFileManager fileManager;

    
Dependency tracker
/** Dependency tracker
     */
    private final Dependencies dependencies;

    
Factory for diagnostics
/** Factory for diagnostics
     */
    JCDiagnostic.Factory diagFactory;

    
Can be reassigned from outside:
 the completer to be used for ".java" files. If this remains unassigned
 ".java" files will not be loaded.
/** Can be reassigned from outside:
     *  the completer to be used for ".java" files. If this remains unassigned
     *  ".java" files will not be loaded.
     */
    public Completer sourceCompleter = Completer.NULL_COMPLETER;

    
The path name of the class file currently being read.
/** The path name of the class file currently being read.
     */
    protected JavaFileObject currentClassFile = null;

    
The class or method currently being read.
/** The class or method currently being read.
     */
    protected Symbol currentOwner = null;

    
The currently selected profile.
/**
     * The currently selected profile.
     */
    private final Profile profile;

    
Use direct access to the JRTIndex to access the temporary
replacement for the info that used to be in ct.sym.
In time, this will go away and be replaced by the module system.
/**
     * Use direct access to the JRTIndex to access the temporary
     * replacement for the info that used to be in ct.sym.
     * In time, this will go away and be replaced by the module system.
     */
    private final JRTIndex jrtIndex;

    
Completer that delegates to the complete-method of this class.
/**
     * Completer that delegates to the complete-method of this class.
     */
    private final Completer thisCompleter = this::complete;

    public Completer getCompleter() {
        return thisCompleter;
    }

    
Get the ClassFinder instance for this invocation. /** Get the ClassFinder instance for this invocation. */
    public static ClassFinder instance(Context context) {
        ClassFinder instance = context.get(classFinderKey);
        if (instance == null)
            instance = new ClassFinder(context);
        return instance;
    }

    
Construct a new class finder. /** Construct a new class finder. */
    protected ClassFinder(Context context) {
        context.put(classFinderKey, this);
        reader = ClassReader.instance(context);
        names = Names.instance(context);
        syms = Symtab.instance(context);
        fileManager = context.get(JavaFileManager.class);
        dependencies = Dependencies.instance(context);
        if (fileManager == null)
            throw new AssertionError("FileManager initialization error");
        diagFactory = JCDiagnostic.Factory.instance(context);

        log = Log.instance(context);
        annotate = Annotate.instance(context);

        Options options = Options.instance(context);
        verbose = options.isSet(Option.VERBOSE);
        cacheCompletionFailure = options.isUnset("dev");
        preferSource = "source".equals(options.get("-Xprefer"));
        userPathsFirst = options.isSet(Option.XXUSERPATHSFIRST);
        allowSigFiles = context.get(PlatformDescription.class) != null;

        completionFailureName =
            options.isSet("failcomplete")
            ? names.fromString(options.get("failcomplete"))
            : null;

        // Temporary, until more info is available from the module system.
        boolean useCtProps;
        JavaFileManager fm = context.get(JavaFileManager.class);
        if (fm instanceof JavacFileManager) {
            JavacFileManager jfm = (JavacFileManager) fm;
            useCtProps = jfm.isDefaultBootClassPath() && jfm.isSymbolFileEnabled();
        } else if (fm.getClass().getName().equals("com.sun.tools.sjavac.comp.SmartFileManager")) {
            useCtProps = !options.isSet("ignore.symbol.file");
        } else {
            useCtProps = false;
        }
        jrtIndex = useCtProps && JRTIndex.isAvailable() ? JRTIndex.getSharedInstance() : null;

        profile = Profile.instance(context);
    }


/************************************************************************
 * Temporary ct.sym replacement
 *
 * The following code is a temporary substitute for the ct.sym mechanism
 * used in JDK 6 thru JDK 8.
 * This mechanism will eventually be superseded by the Jigsaw module system.
 ***********************************************************************/

    
Returns any extra flags for a class symbol.
This information used to be provided using private annotations
in the class file in ct.sym; in time, this information will be
available from the module system.
/**
     * Returns any extra flags for a class symbol.
     * This information used to be provided using private annotations
     * in the class file in ct.sym; in time, this information will be
     * available from the module system.
     */
    long getSupplementaryFlags(ClassSymbol c) {
        if (jrtIndex == null || !jrtIndex.isInJRT(c.classfile) || c.name == names.module_info) {
            return 0;
        }

        if (supplementaryFlags == null) {
            supplementaryFlags = new HashMap<>();
        }

        Long flags = supplementaryFlags.get(c.packge());
        if (flags == null) {
            long newFlags = 0;
            try {
                JRTIndex.CtSym ctSym = jrtIndex.getCtSym(c.packge().flatName());
                Profile minProfile = Profile.DEFAULT;
                if (ctSym.proprietary)
                    newFlags |= PROPRIETARY;
                if (ctSym.minProfile != null)
                    minProfile = Profile.lookup(ctSym.minProfile);
                if (profile != Profile.DEFAULT && minProfile.value > profile.value) {
                    newFlags |= NOT_IN_PROFILE;
                }
            } catch (IOException ignore) {
            }
            supplementaryFlags.put(c.packge(), flags = newFlags);
        }
        return flags;
    }

    private Map<PackageSymbol, Long> supplementaryFlags;

/************************************************************************
 * Loading Classes
 ***********************************************************************/

    
Completion for classes to be loaded. Before a class is loaded
 we make sure its enclosing class (if any) is loaded.
/** Completion for classes to be loaded. Before a class is loaded
     *  we make sure its enclosing class (if any) is loaded.
     */
    private void complete(Symbol sym) throws CompletionFailure {
        if (sym.kind == TYP) {
            try {
                ClassSymbol c = (ClassSymbol) sym;
                dependencies.push(c, CompletionCause.CLASS_READER);
                annotate.blockAnnotations();
                c.members_field = new Scope.ErrorScope(c); // make sure it's always defined
                completeOwners(c.owner);
                completeEnclosing(c);
                fillIn(c);
            } finally {
                annotate.unblockAnnotationsNoFlush();
                dependencies.pop();
            }
        } else if (sym.kind == PCK) {
            PackageSymbol p = (PackageSymbol)sym;
            try {
                fillIn(p);
            } catch (IOException ex) {
                throw new CompletionFailure(sym, ex.getLocalizedMessage()).initCause(ex);
            }
        }
        if (!reader.filling)
            annotate.flush(); // finish attaching annotations
    }

    
complete up through the enclosing package. /** complete up through the enclosing package. */
    private void completeOwners(Symbol o) {
        if (o.kind != PCK) completeOwners(o.owner);
        o.complete();
    }

    
Tries to complete lexically enclosing classes if c looks like a
nested class.  This is similar to completeOwners but handles
the situation when a nested class is accessed directly as it is
possible with the Tree API or javax.lang.model.*.
/**
     * Tries to complete lexically enclosing classes if c looks like a
     * nested class.  This is similar to completeOwners but handles
     * the situation when a nested class is accessed directly as it is
     * possible with the Tree API or javax.lang.model.*.
     */
    private void completeEnclosing(ClassSymbol c) {
        if (c.owner.kind == PCK) {
            Symbol owner = c.owner;
            for (Name name : Convert.enclosingCandidates(Convert.shortName(c.name))) {
                Symbol encl = owner.members().findFirst(name);
                if (encl == null)
                    encl = syms.getClass(c.packge().modle, TypeSymbol.formFlatName(name, owner));
                if (encl != null)
                    encl.complete();
            }
        }
    }

    
Fill in definition of class `c' from corresponding class or
 source file.
/** Fill in definition of class `c' from corresponding class or
     *  source file.
     */
    void fillIn(ClassSymbol c) {
        if (completionFailureName == c.fullname) {
            throw new CompletionFailure(c, "user-selected completion failure by class name");
        }
        currentOwner = c;
        JavaFileObject classfile = c.classfile;
        if (classfile != null) {
            JavaFileObject previousClassFile = currentClassFile;
            try {
                if (reader.filling) {
                    Assert.error("Filling " + classfile.toUri() + " during " + previousClassFile);
                }
                currentClassFile = classfile;
                if (verbose) {
                    log.printVerbose("loading", currentClassFile.getName());
                }
                if (classfile.getKind() == JavaFileObject.Kind.CLASS ||
                    classfile.getKind() == JavaFileObject.Kind.OTHER) {
                    reader.readClassFile(c);
                    c.flags_field |= getSupplementaryFlags(c);
                } else {
                    if (!sourceCompleter.isTerminal()) {
                        sourceCompleter.complete(c);
                    } else {
                        throw new IllegalStateException("Source completer required to read "
                                                        + classfile.toUri());
                    }
                }
            } finally {
                currentClassFile = previousClassFile;
            }
        } else {
            throw classFileNotFound(c);
        }
    }
    // where
        private CompletionFailure classFileNotFound(ClassSymbol c) {
            JCDiagnostic diag =
                diagFactory.fragment("class.file.not.found", c.flatname);
            return newCompletionFailure(c, diag);
        }
        
Static factory for CompletionFailure objects.
 In practice, only one can be used at a time, so we share one
 to reduce the expense of allocating new exception objects.
/** Static factory for CompletionFailure objects.
         *  In practice, only one can be used at a time, so we share one
         *  to reduce the expense of allocating new exception objects.
         */
        private CompletionFailure newCompletionFailure(TypeSymbol c,
                                                       JCDiagnostic diag) {
            if (!cacheCompletionFailure) {
                // log.warning("proc.messager",
                //             Log.getLocalizedString("class.file.not.found", c.flatname));
                // c.debug.printStackTrace();
                return new CompletionFailure(c, diag);
            } else {
                CompletionFailure result = cachedCompletionFailure;
                result.sym = c;
                result.diag = diag;
                return result;
            }
        }
        private final CompletionFailure cachedCompletionFailure =
            new CompletionFailure(null, (JCDiagnostic) null);
        {
            cachedCompletionFailure.setStackTrace(new StackTraceElement[0]);
        }


    
Load a toplevel class with given fully qualified name
 The class is entered into `classes' only if load was successful.
/** Load a toplevel class with given fully qualified name
     *  The class is entered into `classes' only if load was successful.
     */
    public ClassSymbol loadClass(ModuleSymbol msym, Name flatname) throws CompletionFailure {
        Assert.checkNonNull(msym);
        Name packageName = Convert.packagePart(flatname);
        PackageSymbol ps = syms.lookupPackage(msym, packageName);

        Assert.checkNonNull(ps.modle, () -> "msym=" + msym + "; flatName=" + flatname);

        boolean absent = syms.getClass(ps.modle, flatname) == null;
        ClassSymbol c = syms.enterClass(ps.modle, flatname);

        if (c.members_field == null) {
            try {
                c.complete();
            } catch (CompletionFailure ex) {
                if (absent) syms.removeClass(ps.modle, flatname);
                throw ex;
            }
        }
        return c;
    }

/************************************************************************
 * Loading Packages
 ***********************************************************************/

    
Include class corresponding to given class file in package,
 unless (1) we already have one the same kind (.class or .java), or
        (2) we have one of the other kind, and the given class file
            is older.
/** Include class corresponding to given class file in package,
     *  unless (1) we already have one the same kind (.class or .java), or
     *         (2) we have one of the other kind, and the given class file
     *             is older.
     */
    protected void includeClassFile(PackageSymbol p, JavaFileObject file) {
        if ((p.flags_field & EXISTS) == 0)
            for (Symbol q = p; q != null && q.kind == PCK; q = q.owner)
                q.flags_field |= EXISTS;
        JavaFileObject.Kind kind = file.getKind();
        int seen;
        if (kind == JavaFileObject.Kind.CLASS || kind == JavaFileObject.Kind.OTHER)
            seen = CLASS_SEEN;
        else
            seen = SOURCE_SEEN;
        String binaryName = fileManager.inferBinaryName(currentLoc, file);
        int lastDot = binaryName.lastIndexOf(".");
        Name classname = names.fromString(binaryName.substring(lastDot + 1));
        boolean isPkgInfo = classname == names.package_info;
        ClassSymbol c = isPkgInfo
            ? p.package_info
            : (ClassSymbol) p.members_field.findFirst(classname);
        if (c == null) {
            c = syms.enterClass(p.modle, classname, p);
            if (c.classfile == null) // only update the file if's it's newly created
                c.classfile = file;
            if (isPkgInfo) {
                p.package_info = c;
            } else {
                if (c.owner == p)  // it might be an inner class
                    p.members_field.enter(c);
            }
        } else if (!preferCurrent && c.classfile != null && (c.flags_field & seen) == 0) {
            // if c.classfile == null, we are currently compiling this class
            // and no further action is necessary.
            // if (c.flags_field & seen) != 0, we have already encountered
            // a file of the same kind; again no further action is necessary.
            if ((c.flags_field & (CLASS_SEEN | SOURCE_SEEN)) != 0)
                c.classfile = preferredFileObject(file, c.classfile);
        }
        c.flags_field |= seen;
    }

    
Implement policy to choose to derive information from a source
 file or a class file when both are present.  May be overridden
 by subclasses.
/** Implement policy to choose to derive information from a source
     *  file or a class file when both are present.  May be overridden
     *  by subclasses.
     */
    protected JavaFileObject preferredFileObject(JavaFileObject a,
                                           JavaFileObject b) {

        if (preferSource)
            return (a.getKind() == JavaFileObject.Kind.SOURCE) ? a : b;
        else {
            long adate = a.getLastModified();
            long bdate = b.getLastModified();
            // 6449326: policy for bad lastModifiedTime in ClassReader
            //assert adate >= 0 && bdate >= 0;
            return (adate > bdate) ? a : b;
        }
    }

    
specifies types of files to be read when filling in a package symbol
/**
     * specifies types of files to be read when filling in a package symbol
     */
    // Note: overridden by JavadocClassFinder
    protected EnumSet<JavaFileObject.Kind> getPackageFileKinds() {
        return EnumSet.of(JavaFileObject.Kind.CLASS, JavaFileObject.Kind.SOURCE);
    }

    
this is used to support javadoc
/**
     * this is used to support javadoc
     */
    protected void extraFileActions(PackageSymbol pack, JavaFileObject fe) {
    }

    protected Location currentLoc; // FIXME

    private boolean verbosePath = true;

    // Set to true when the currently selected file should be kept
    private boolean preferCurrent;

    
Load directory of package into members scope.
/** Load directory of package into members scope.
     */
    private void fillIn(PackageSymbol p) throws IOException {
        if (p.members_field == null)
            p.members_field = WriteableScope.create(p);

        ModuleSymbol msym = p.modle;

        Assert.checkNonNull(msym, p::toString);

        msym.complete();

        if (msym == syms.noModule) {
            preferCurrent = false;
            if (userPathsFirst) {
                scanUserPaths(p, true);
                preferCurrent = true;
                scanPlatformPath(p);
            } else {
                scanPlatformPath(p);
                scanUserPaths(p, true);
            }
        } else if (msym.classLocation == StandardLocation.CLASS_PATH) {
            scanUserPaths(p, msym.sourceLocation == StandardLocation.SOURCE_PATH);
        } else {
            scanModulePaths(p, msym);
        }
    }

    // TODO: for now, this is a much simplified form of scanUserPaths
    // and (deliberately) does not default sourcepath to classpath.
    // But, we need to think about retaining existing behavior for
    // -classpath and -sourcepath for single module mode.
    // One plausible solution is to detect if the module's sourceLocation
    // is the same as the module's classLocation.
    private void scanModulePaths(PackageSymbol p, ModuleSymbol msym) throws IOException {
        Set<JavaFileObject.Kind> kinds = getPackageFileKinds();

        Set<JavaFileObject.Kind> classKinds = EnumSet.copyOf(kinds);
        classKinds.remove(JavaFileObject.Kind.SOURCE);
        boolean wantClassFiles = !classKinds.isEmpty();

        Set<JavaFileObject.Kind> sourceKinds = EnumSet.copyOf(kinds);
        sourceKinds.remove(JavaFileObject.Kind.CLASS);
        boolean wantSourceFiles = !sourceKinds.isEmpty();

        String packageName = p.fullname.toString();

        Location classLocn = msym.classLocation;
        Location sourceLocn = msym.sourceLocation;
        Location patchLocn = msym.patchLocation;
        Location patchOutLocn = msym.patchOutputLocation;

        boolean prevPreferCurrent = preferCurrent;

        try {
            preferCurrent = false;
            if (wantClassFiles && (patchOutLocn != null)) {
                fillIn(p, patchOutLocn,
                       list(patchOutLocn,
                            p,
                            packageName,
                            classKinds));
            }
            if ((wantClassFiles || wantSourceFiles) && (patchLocn != null)) {
                Set<JavaFileObject.Kind> combined = EnumSet.noneOf(JavaFileObject.Kind.class);
                combined.addAll(classKinds);
                combined.addAll(sourceKinds);
                fillIn(p, patchLocn,
                       list(patchLocn,
                            p,
                            packageName,
                            combined));
            }
            preferCurrent = true;
            if (wantClassFiles && (classLocn != null)) {
                fillIn(p, classLocn,
                       list(classLocn,
                            p,
                            packageName,
                            classKinds));
            }
            if (wantSourceFiles && (sourceLocn != null)) {
                fillIn(p, sourceLocn,
                       list(sourceLocn,
                            p,
                            packageName,
                            sourceKinds));
            }
        } finally {
            preferCurrent = prevPreferCurrent;
        }
    }

    
Scans class path and source path for files in given package.
/**
     * Scans class path and source path for files in given package.
     */
    private void scanUserPaths(PackageSymbol p, boolean includeSourcePath) throws IOException {
        Set<JavaFileObject.Kind> kinds = getPackageFileKinds();

        Set<JavaFileObject.Kind> classKinds = EnumSet.copyOf(kinds);
        classKinds.remove(JavaFileObject.Kind.SOURCE);
        boolean wantClassFiles = !classKinds.isEmpty();

        Set<JavaFileObject.Kind> sourceKinds = EnumSet.copyOf(kinds);
        sourceKinds.remove(JavaFileObject.Kind.CLASS);
        boolean wantSourceFiles = !sourceKinds.isEmpty();

        boolean haveSourcePath = includeSourcePath && fileManager.hasLocation(SOURCE_PATH);

        if (verbose && verbosePath) {
            if (fileManager instanceof StandardJavaFileManager) {
                StandardJavaFileManager fm = (StandardJavaFileManager)fileManager;
                if (haveSourcePath && wantSourceFiles) {
                    List<Path> path = List.nil();
                    for (Path sourcePath : fm.getLocationAsPaths(SOURCE_PATH)) {
                        path = path.prepend(sourcePath);
                    }
                    log.printVerbose("sourcepath", path.reverse().toString());
                } else if (wantSourceFiles) {
                    List<Path> path = List.nil();
                    for (Path classPath : fm.getLocationAsPaths(CLASS_PATH)) {
                        path = path.prepend(classPath);
                    }
                    log.printVerbose("sourcepath", path.reverse().toString());
                }
                if (wantClassFiles) {
                    List<Path> path = List.nil();
                    for (Path platformPath : fm.getLocationAsPaths(PLATFORM_CLASS_PATH)) {
                        path = path.prepend(platformPath);
                    }
                    for (Path classPath : fm.getLocationAsPaths(CLASS_PATH)) {
                        path = path.prepend(classPath);
                    }
                    log.printVerbose("classpath",  path.reverse().toString());
                }
            }
        }

        String packageName = p.fullname.toString();
        if (wantSourceFiles && !haveSourcePath) {
            fillIn(p, CLASS_PATH,
                   list(CLASS_PATH,
                        p,
                        packageName,
                        kinds));
        } else {
            if (wantClassFiles)
                fillIn(p, CLASS_PATH,
                       list(CLASS_PATH,
                            p,
                            packageName,
                            classKinds));
            if (wantSourceFiles)
                fillIn(p, SOURCE_PATH,
                       list(SOURCE_PATH,
                            p,
                            packageName,
                            sourceKinds));
        }
    }

    
Scans platform class path for files in given package.
/**
     * Scans platform class path for files in given package.
     */
    private void scanPlatformPath(PackageSymbol p) throws IOException {
        fillIn(p, PLATFORM_CLASS_PATH,
               list(PLATFORM_CLASS_PATH,
                    p,
                    p.fullname.toString(),
                    allowSigFiles ? EnumSet.of(JavaFileObject.Kind.CLASS,
                                               JavaFileObject.Kind.OTHER)
                                  : EnumSet.of(JavaFileObject.Kind.CLASS)));
    }
    // where
        @SuppressWarnings("fallthrough")
        private void fillIn(PackageSymbol p,
                            Location location,
                            Iterable<JavaFileObject> files)
        {
            currentLoc = location;
            for (JavaFileObject fo : files) {
                switch (fo.getKind()) {
                case OTHER:
                    if (!isSigFile(location, fo)) {
                        extraFileActions(p, fo);
                        break;
                    }
                    //intentional fall-through:
                case CLASS:
                case SOURCE: {
                    // TODO pass binaryName to includeClassFile
                    String binaryName = fileManager.inferBinaryName(currentLoc, fo);
                    String simpleName = binaryName.substring(binaryName.lastIndexOf(".") + 1);
                    if (SourceVersion.isIdentifier(simpleName) ||
                        simpleName.equals("package-info"))
                        includeClassFile(p, fo);
                    break;
                }
                default:
                    extraFileActions(p, fo);
                    break;
                }
            }
        }

        boolean isSigFile(Location location, JavaFileObject fo) {
            return location == PLATFORM_CLASS_PATH &&
                   allowSigFiles &&
                   fo.getName().endsWith(".sig");
        }

        Iterable<JavaFileObject> list(Location location,
                                      PackageSymbol p,
                                      String packageName,
                                      Set<Kind> kinds) throws IOException {
            Iterable<JavaFileObject> listed = fileManager.list(location,
                                                               packageName,
                                                               EnumSet.allOf(Kind.class),
                                                               false);
            return () -> new Iterator<JavaFileObject>() {
                private final Iterator<JavaFileObject> original = listed.iterator();
                private JavaFileObject next;
                @Override
                public boolean hasNext() {
                    if (next == null) {
                        while (original.hasNext()) {
                            JavaFileObject fo = original.next();

                            if (fo.getKind() != Kind.CLASS &&
                                fo.getKind() != Kind.SOURCE &&
                                !isSigFile(currentLoc, fo)) {
                                p.flags_field |= Flags.HAS_RESOURCE;
                            }

                            if (kinds.contains(fo.getKind())) {
                                next = fo;
                                break;
                            }
                        }
                    }
                    return next != null;
                }

                @Override
                public JavaFileObject next() {
                    if (!hasNext())
                        throw new NoSuchElementException();
                    JavaFileObject result = next;
                    next = null;
                    return result;
                }

            };
        }

    
Used for bad class definition files, such as bad .class files or
for .java files with unexpected package or class names.
/**
     * Used for bad class definition files, such as bad .class files or
     * for .java files with unexpected package or class names.
     */
    public static class BadClassFile extends CompletionFailure {
        private static final long serialVersionUID = 0;

        public BadClassFile(TypeSymbol sym, JavaFileObject file, JCDiagnostic diag,
                JCDiagnostic.Factory diagFactory) {
            super(sym, createBadClassFileDiagnostic(file, diag, diagFactory));
        }
        // where
        private static JCDiagnostic createBadClassFileDiagnostic(
                JavaFileObject file, JCDiagnostic diag, JCDiagnostic.Factory diagFactory) {
            String key = (file.getKind() == JavaFileObject.Kind.SOURCE
                        ? "bad.source.file.header" : "bad.class.file.header");
            return diagFactory.fragment(key, file, diag);
        }
    }

    public static class BadEnclosingMethodAttr extends BadClassFile {
        private static final long serialVersionUID = 0;

        public BadEnclosingMethodAttr(TypeSymbol sym, JavaFileObject file, JCDiagnostic diag,
                JCDiagnostic.Factory diagFactory) {
            super(sym, file, diag, diagFactory);
        }
    }
}