/*

 * Copyright (c) 1999, 2019, 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.util.Collections;

import java.util.EnumSet;

import java.util.Map;

import java.util.Set;

import java.util.concurrent.ConcurrentHashMap;

import javax.lang.model.element.Modifier;

import com.sun.tools.javac.util.Assert;

import com.sun.tools.javac.util.StringUtils;

/** Access flags and other modifiers for Java classes and members.

 *

 *  <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 Flags {

    private Flags() {} // uninstantiable

    public static String toString(long flags) {

        StringBuilder buf = new StringBuilder();

        String sep = "";

        for (Flag flag : asFlagSet(flags)) {

            buf.append(sep);

            buf.append(flag);

            sep = " ";

        }

        return buf.toString();

    }

    public static EnumSet<Flag> asFlagSet(long flags) {

        EnumSet<Flag> flagSet = EnumSet.noneOf(Flag.class);

        for (Flag flag : Flag.values()) {

            if ((flags & flag.value) != 0) {

                flagSet.add(flag);

                flags &= ~flag.value;

            }

        }

        Assert.check(flags == 0);

        return flagSet;

    }

    /* Standard Java flags.

     */

    public static final int PUBLIC       = 1;

    public static final int PRIVATE      = 1<<1;

    public static final int PROTECTED    = 1<<2;

    public static final int STATIC       = 1<<3;

    public static final int FINAL        = 1<<4;

    public static final int SYNCHRONIZED = 1<<5;

    public static final int VOLATILE     = 1<<6;

    public static final int TRANSIENT    = 1<<7;

    public static final int NATIVE       = 1<<8;

    public static final int INTERFACE    = 1<<9;

    public static final int ABSTRACT     = 1<<10;

    public static final int STRICTFP     = 1<<11;

    /* Flag that marks a symbol synthetic, added in classfile v49.0. */

    public static final int SYNTHETIC    = 1<<12;

    /** Flag that marks attribute interfaces, added in classfile v49.0. */

    public static final int ANNOTATION   = 1<<13;

    /** An enumeration type or an enumeration constant, added in

     *  classfile v49.0. */

    public static final int ENUM         = 1<<14;

    /** Added in SE8, represents constructs implicitly declared in source. */

    public static final int MANDATED     = 1<<15;

    public static final int StandardFlags = 0x0fff;

    // Because the following access flags are overloaded with other

    // bit positions, we translate them when reading and writing class

    // files into unique bits positions: ACC_SYNTHETIC <-> SYNTHETIC,

    // for example.

    public static final int ACC_SUPER    = 0x0020;

    public static final int ACC_BRIDGE   = 0x0040;

    public static final int ACC_VARARGS  = 0x0080;

    public static final int ACC_MODULE   = 0x8000;

    /*****************************************

     * Internal compiler flags (no bits in the lower 16).

     *****************************************/

    /** Flag is set if symbol is deprecated.  See also DEPRECATED_REMOVAL.

     */

    public static final int DEPRECATED   = 1<<17;

    /** Flag is set for a variable symbol if the variable's definition

     *  has an initializer part.

     */

    public static final int HASINIT          = 1<<18;

    /** Flag is set for compiler-generated anonymous method symbols

     *  that `own' an initializer block.

     */

    public static final int BLOCK            = 1<<20;

    /** Flag bit 21 is available. (used earlier to tag compiler-generated abstract methods that implement

     *  an interface method (Miranda methods)).

     */

    /** Flag is set for nested classes that do not access instance members

     *  or `this' of an outer class and therefore don't need to be passed

     *  a this$n reference.  This value is currently set only for anonymous

     *  classes in superclass constructor calls.

     *  todo: use this value for optimizing away this$n parameters in

     *  other cases.

     */

    public static final int NOOUTERTHIS  = 1<<22;

    /** Flag is set for package symbols if a package has a member or

     *  directory and therefore exists.

     */

    public static final int EXISTS           = 1<<23;

    /** Flag is set for compiler-generated compound classes

     *  representing multiple variable bounds

     */

    public static final int COMPOUND     = 1<<24;

    /** Flag is set for class symbols if a class file was found for this class.

     */

    public static final int CLASS_SEEN   = 1<<25;

    /** Flag is set for class symbols if a source file was found for this

     *  class.

     */

    public static final int SOURCE_SEEN  = 1<<26;

    /* State flags (are reset during compilation).

     */

    /** Flag for class symbols is set and later re-set as a lock in

     *  Enter to detect cycles in the superclass/superinterface

     *  relations.  Similarly for constructor call cycle detection in

     *  Attr.

     */

    public static final int LOCKED           = 1<<27;

    /** Flag for class symbols is set and later re-set to indicate that a class

     *  has been entered but has not yet been attributed.

     */

    public static final int UNATTRIBUTED = 1<<28;

    /** Flag for synthesized default constructors of anonymous classes.

     */

    public static final int ANONCONSTR   = 1<<29;

    /** Flag for class symbols to indicate it has been checked and found

     *  acyclic.

     */

    public static final int ACYCLIC          = 1<<30;

    /** Flag that marks bridge methods.

     */

    public static final long BRIDGE          = 1L<<31;

    /** Flag that marks formal parameters.

     */

    public static final long PARAMETER   = 1L<<33;

    /** Flag that marks varargs methods.

     */

    public static final long VARARGS   = 1L<<34;

    /** Flag for annotation type symbols to indicate it has been

     *  checked and found acyclic.

     */

    public static final long ACYCLIC_ANN      = 1L<<35;

    /** Flag that marks a generated default constructor.

     */

    public static final long GENERATEDCONSTR   = 1L<<36;

    /** Flag that marks a hypothetical method that need not really be

     *  generated in the binary, but is present in the symbol table to

     *  simplify checking for erasure clashes - also used for 292 poly sig methods.

     */

    public static final long HYPOTHETICAL   = 1L<<37;

    /**

     * Flag that marks an internal proprietary class.

     */

    public static final long PROPRIETARY = 1L<<38;

    /**

     * Flag that marks a multi-catch parameter.

     */

    public static final long UNION = 1L<<39;

    // Flag bit (1L << 40) is available.

    /**

     * Flag that marks an 'effectively final' local variable.

     */

    public static final long EFFECTIVELY_FINAL = 1L<<41;

    /**

     * Flag that marks non-override equivalent methods with the same signature.

     */

    public static final long CLASH = 1L<<42;

    /**

     * Flag that marks either a default method or an interface containing default methods.

     */

    public static final long DEFAULT = 1L<<43;

    /**

     * Flag that marks class as auxiliary, ie a non-public class following

     * the public class in a source file, that could block implicit compilation.

     */

    public static final long AUXILIARY = 1L<<44;

    /**

     * Flag that marks that a symbol is not available in the current profile

     */

    public static final long NOT_IN_PROFILE = 1L<<45;

    /**

     * Flag that indicates that an override error has been detected by Check.

     */

    public static final long BAD_OVERRIDE = 1L<<45;

    /**

     * Flag that indicates a signature polymorphic method (292).

     */

    public static final long SIGNATURE_POLYMORPHIC = 1L<<46;

    /**

     * Flag that indicates that an inference variable is used in a 'throws' clause.

     */

    public static final long THROWS = 1L<<47;

    /**

     * Flag that marks potentially ambiguous overloads

     */

    public static final long POTENTIALLY_AMBIGUOUS = 1L<<48;

    /**

     * Flag that marks a synthetic method body for a lambda expression

     */

    public static final long LAMBDA_METHOD = 1L<<49;

    /**

     * Flag to control recursion in TransTypes

     */

    public static final long TYPE_TRANSLATED = 1L<<50;

    /**

     * Flag to indicate class symbol is for module-info

     */

    public static final long MODULE = 1L<<51;

    /**

     * Flag to indicate the given ModuleSymbol is an automatic module.

     */

    /**

     * Flag to indicate the given ModuleSymbol is a system module.

     */

    public static final long SYSTEM_MODULE = 1L<<53;

    /**

     * Flag to indicate the given symbol has a @Deprecated annotation.

     */

    public static final long DEPRECATED_ANNOTATION = 1L<<54;

    /**

     * Flag to indicate the given symbol has been deprecated and marked for removal.

     */

    public static final long DEPRECATED_REMOVAL = 1L<<55;

    /**

     */

    /**

     * Flag for synthesized default constructors of anonymous classes that have an enclosing expression.

     */

    public static final long ANONCONSTR_BASED = 1L<<57;

    /**

     * Flag that marks finalize block as body-only, should not be copied into catch clauses.

     * Used to implement try-with-resources.

     */

    public static final long BODY_ONLY_FINALIZE = 1L<<17; //blocks only

    /**

     */

    /** Modifier masks.

     */

    public static final int

        AccessFlags           = PUBLIC | PROTECTED | PRIVATE,

        LocalClassFlags       = FINAL | ABSTRACT | STRICTFP | ENUM | SYNTHETIC,

        MemberClassFlags      = LocalClassFlags | INTERFACE | AccessFlags,

        ClassFlags            = LocalClassFlags | INTERFACE | PUBLIC | ANNOTATION,

        InterfaceVarFlags     = FINAL | STATIC | PUBLIC,

        VarFlags              = AccessFlags | FINAL | STATIC |

                                VOLATILE | TRANSIENT | ENUM,

        ConstructorFlags      = AccessFlags,

        InterfaceMethodFlags  = ABSTRACT | PUBLIC,

        MethodFlags           = AccessFlags | ABSTRACT | STATIC | NATIVE |

                                SYNCHRONIZED | FINAL | STRICTFP;

    public static final long

        ExtendedStandardFlags       = (long)StandardFlags | DEFAULT,

        ModifierFlags               = ((long)StandardFlags & ~INTERFACE) | DEFAULT,

        InterfaceMethodMask         = ABSTRACT | PRIVATE | STATIC | PUBLIC | STRICTFP | DEFAULT,

        AnnotationTypeElementMask   = ABSTRACT | PUBLIC,

        LocalVarFlags               = FINAL | PARAMETER,

        ReceiverParamFlags          = PARAMETER;

    public static Set<Modifier> asModifierSet(long flags) {

        Set<Modifier> modifiers = modifierSets.get(flags);

        if (modifiers == null) {

            modifiers = java.util.EnumSet.noneOf(Modifier.class);

            if (0 != (flags & PUBLIC))    modifiers.add(Modifier.PUBLIC);

            if (0 != (flags & PROTECTED)) modifiers.add(Modifier.PROTECTED);

            if (0 != (flags & PRIVATE))   modifiers.add(Modifier.PRIVATE);

            if (0 != (flags & ABSTRACT))  modifiers.add(Modifier.ABSTRACT);

            if (0 != (flags & STATIC))    modifiers.add(Modifier.STATIC);

            if (0 != (flags & FINAL))     modifiers.add(Modifier.FINAL);

            if (0 != (flags & TRANSIENT)) modifiers.add(Modifier.TRANSIENT);

            if (0 != (flags & VOLATILE))  modifiers.add(Modifier.VOLATILE);

            if (0 != (flags & SYNCHRONIZED))

                                          modifiers.add(Modifier.SYNCHRONIZED);

            if (0 != (flags & NATIVE))    modifiers.add(Modifier.NATIVE);

            if (0 != (flags & STRICTFP))  modifiers.add(Modifier.STRICTFP);

            if (0 != (flags & DEFAULT))   modifiers.add(Modifier.DEFAULT);

            modifiers = Collections.unmodifiableSet(modifiers);

            modifierSets.put(flags, modifiers);

        }

        return modifiers;

    }

    // Cache of modifier sets.

    private static final Map<Long, Set<Modifier>> modifierSets = new ConcurrentHashMap<>(64);

    public static boolean isStatic(Symbol symbol) {

        return (symbol.flags() & STATIC) != 0;

    }

    public static boolean isEnum(Symbol symbol) {

        return (symbol.flags() & ENUM) != 0;

    }

    public static boolean isConstant(Symbol.VarSymbol symbol) {

        return symbol.getConstValue() != null;

    }

    public enum Flag {

        PUBLIC(Flags.PUBLIC),

        PRIVATE(Flags.PRIVATE),

        PROTECTED(Flags.PROTECTED),

        STATIC(Flags.STATIC),

        FINAL(Flags.FINAL),

        SYNCHRONIZED(Flags.SYNCHRONIZED),

        VOLATILE(Flags.VOLATILE),

        TRANSIENT(Flags.TRANSIENT),

        NATIVE(Flags.NATIVE),

        INTERFACE(Flags.INTERFACE),

        ABSTRACT(Flags.ABSTRACT),

        DEFAULT(Flags.DEFAULT),

        STRICTFP(Flags.STRICTFP),

        BRIDGE(Flags.BRIDGE),

        SYNTHETIC(Flags.SYNTHETIC),

        ANNOTATION(Flags.ANNOTATION),

        DEPRECATED(Flags.DEPRECATED),

        HASINIT(Flags.HASINIT),

        BLOCK(Flags.BLOCK),

        ENUM(Flags.ENUM),

        MANDATED(Flags.MANDATED),

        NOOUTERTHIS(Flags.NOOUTERTHIS),

        EXISTS(Flags.EXISTS),

        COMPOUND(Flags.COMPOUND),

        CLASS_SEEN(Flags.CLASS_SEEN),

        SOURCE_SEEN(Flags.SOURCE_SEEN),

        LOCKED(Flags.LOCKED),

        UNATTRIBUTED(Flags.UNATTRIBUTED),

        ANONCONSTR(Flags.ANONCONSTR),

        ACYCLIC(Flags.ACYCLIC),

        PARAMETER(Flags.PARAMETER),

        VARARGS(Flags.VARARGS),

        ACYCLIC_ANN(Flags.ACYCLIC_ANN),

        GENERATEDCONSTR(Flags.GENERATEDCONSTR),

        HYPOTHETICAL(Flags.HYPOTHETICAL),

        PROPRIETARY(Flags.PROPRIETARY),

        UNION(Flags.UNION),

        EFFECTIVELY_FINAL(Flags.EFFECTIVELY_FINAL),

        CLASH(Flags.CLASH),

        AUXILIARY(Flags.AUXILIARY),

        NOT_IN_PROFILE(Flags.NOT_IN_PROFILE),

        BAD_OVERRIDE(Flags.BAD_OVERRIDE),

        SIGNATURE_POLYMORPHIC(Flags.SIGNATURE_POLYMORPHIC),

        THROWS(Flags.THROWS),

        LAMBDA_METHOD(Flags.LAMBDA_METHOD),

        TYPE_TRANSLATED(Flags.TYPE_TRANSLATED),

        MODULE(Flags.MODULE),

        AUTOMATIC_MODULE(Flags.AUTOMATIC_MODULE),

        SYSTEM_MODULE(Flags.SYSTEM_MODULE),

        DEPRECATED_ANNOTATION(Flags.DEPRECATED_ANNOTATION),

        DEPRECATED_REMOVAL(Flags.DEPRECATED_REMOVAL),

        HAS_RESOURCE(Flags.HAS_RESOURCE),

        POTENTIALLY_AMBIGUOUS(Flags.POTENTIALLY_AMBIGUOUS),

        ANONCONSTR_BASED(Flags.ANONCONSTR_BASED),

        Flag(long flag) {

            this.value = flag;

            this.lowercaseName = StringUtils.toLowerCase(name());

        }

        @Override

        public String toString() {

            return lowercaseName;

        }

        final long value;

        final String lowercaseName;

    }

}