/*

 * Copyright (c) 1999, 2011, 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.tree;

import com.sun.source.tree.Tree;

import com.sun.tools.javac.comp.AttrContext;

import com.sun.tools.javac.comp.Env;

import java.util.Map;

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

import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;

import com.sun.tools.javac.code.*;

import com.sun.tools.javac.tree.JCTree.*;

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

/** Utility class containing inspector methods for trees.

 *

 *  <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 TreeInfo {

    protected static final Context.Key<TreeInfo> treeInfoKey =

        new Context.Key<TreeInfo>();

    public static TreeInfo instance(Context context) {

        TreeInfo instance = context.get(treeInfoKey);

        if (instance == null)

            instance = new TreeInfo(context);

        return instance;

    }

    /** The names of all operators.

     */

    private Name[] opname = new Name[JCTree.MOD - JCTree.POS + 1];

    private TreeInfo(Context context) {

        context.put(treeInfoKey, this);

        Names names = Names.instance(context);

        opname[JCTree.POS     - JCTree.POS] = names.fromString("+");

        opname[JCTree.NEG     - JCTree.POS] = names.hyphen;

        opname[JCTree.NOT     - JCTree.POS] = names.fromString("!");

        opname[JCTree.COMPL   - JCTree.POS] = names.fromString("~");

        opname[JCTree.PREINC  - JCTree.POS] = names.fromString("++");

        opname[JCTree.PREDEC  - JCTree.POS] = names.fromString("--");

        opname[JCTree.POSTINC - JCTree.POS] = names.fromString("++");

        opname[JCTree.POSTDEC - JCTree.POS] = names.fromString("--");

        opname[JCTree.NULLCHK - JCTree.POS] = names.fromString("<*nullchk*>");

        opname[JCTree.OR      - JCTree.POS] = names.fromString("||");

        opname[JCTree.AND     - JCTree.POS] = names.fromString("&&");

        opname[JCTree.EQ      - JCTree.POS] = names.fromString("==");

        opname[JCTree.NE      - JCTree.POS] = names.fromString("!=");

        opname[JCTree.LT      - JCTree.POS] = names.fromString("<");

        opname[JCTree.GT      - JCTree.POS] = names.fromString(">");

        opname[JCTree.LE      - JCTree.POS] = names.fromString("<=");

        opname[JCTree.GE      - JCTree.POS] = names.fromString(">=");

        opname[JCTree.BITOR   - JCTree.POS] = names.fromString("|");

        opname[JCTree.BITXOR  - JCTree.POS] = names.fromString("^");

        opname[JCTree.BITAND  - JCTree.POS] = names.fromString("&");

        opname[JCTree.SL      - JCTree.POS] = names.fromString("<<");

        opname[JCTree.SR      - JCTree.POS] = names.fromString(">>");

        opname[JCTree.USR     - JCTree.POS] = names.fromString(">>>");

        opname[JCTree.PLUS    - JCTree.POS] = names.fromString("+");

        opname[JCTree.MINUS   - JCTree.POS] = names.hyphen;

        opname[JCTree.MUL     - JCTree.POS] = names.asterisk;

        opname[JCTree.DIV     - JCTree.POS] = names.slash;

        opname[JCTree.MOD     - JCTree.POS] = names.fromString("%");

    }

    /** Return name of operator with given tree tag.

     */

    public Name operatorName(int tag) {

        return opname[tag - JCTree.POS];

    }

    /** Is tree a constructor declaration?

     */

    public static boolean isConstructor(JCTree tree) {

        if (tree.getTag() == JCTree.METHODDEF) {

            Name name = ((JCMethodDecl) tree).name;

            return name == name.table.names.init;

        } else {

            return false;

        }

    }

    /** Is there a constructor declaration in the given list of trees?

     */

    public static boolean hasConstructors(List<JCTree> trees) {

        for (List<JCTree> l = trees; l.nonEmpty(); l = l.tail)

            if (isConstructor(l.head)) return true;

        return false;

    }

    public static boolean isMultiCatch(JCCatch catchClause) {

        return catchClause.param.vartype.getTag() == JCTree.TYPEDISJUNCTION;

    }

    /** Is statement an initializer for a synthetic field?

     */

    public static boolean isSyntheticInit(JCTree stat) {

        if (stat.getTag() == JCTree.EXEC) {

            JCExpressionStatement exec = (JCExpressionStatement)stat;

            if (exec.expr.getTag() == JCTree.ASSIGN) {

                JCAssign assign = (JCAssign)exec.expr;

                if (assign.lhs.getTag() == JCTree.SELECT) {

                    JCFieldAccess select = (JCFieldAccess)assign.lhs;

                    if (select.sym != null &&

                        (select.sym.flags() & SYNTHETIC) != 0) {

                        Name selected = name(select.selected);

                        if (selected != null && selected == selected.table.names._this)

                            return true;

                    }

                }

            }

        }

        return false;

    }

    /** If the expression is a method call, return the method name, null

     *  otherwise. */

    public static Name calledMethodName(JCTree tree) {

        if (tree.getTag() == JCTree.EXEC) {

            JCExpressionStatement exec = (JCExpressionStatement)tree;

            if (exec.expr.getTag() == JCTree.APPLY) {

                Name mname = TreeInfo.name(((JCMethodInvocation) exec.expr).meth);

                return mname;

            }

        }

        return null;

    }

    /** Is this a call to this or super?

     */

    public static boolean isSelfCall(JCTree tree) {

        Name name = calledMethodName(tree);

        if (name != null) {

            Names names = name.table.names;

            return name==names._this || name==names._super;

        } else {

            return false;

        }

    }

    /** Is this a call to super?

     */

    public static boolean isSuperCall(JCTree tree) {

        Name name = calledMethodName(tree);

        if (name != null) {

            Names names = name.table.names;

            return name==names._super;

        } else {

            return false;

        }

    }

    /** Is this a constructor whose first (non-synthetic) statement is not

     *  of the form this(...)?

     */

    public static boolean isInitialConstructor(JCTree tree) {

        JCMethodInvocation app = firstConstructorCall(tree);

        if (app == null) return false;

        Name meth = name(app.meth);

        return meth == null || meth != meth.table.names._this;

    }

    /** Return the first call in a constructor definition. */

    public static JCMethodInvocation firstConstructorCall(JCTree tree) {

        if (tree.getTag() != JCTree.METHODDEF) return null;

        JCMethodDecl md = (JCMethodDecl) tree;

        Names names = md.name.table.names;

        if (md.name != names.init) return null;

        if (md.body == null) return null;

        List<JCStatement> stats = md.body.stats;

        // Synthetic initializations can appear before the super call.

        while (stats.nonEmpty() && isSyntheticInit(stats.head))

            stats = stats.tail;

        if (stats.isEmpty()) return null;

        if (stats.head.getTag() != JCTree.EXEC) return null;

        JCExpressionStatement exec = (JCExpressionStatement) stats.head;

        if (exec.expr.getTag() != JCTree.APPLY) return null;

        return (JCMethodInvocation)exec.expr;

    }

    /** Return true if a tree represents a diamond new expr. */

    public static boolean isDiamond(JCTree tree) {

        switch(tree.getTag()) {

            case JCTree.TYPEAPPLY: return ((JCTypeApply)tree).getTypeArguments().isEmpty();

            case JCTree.NEWCLASS: return isDiamond(((JCNewClass)tree).clazz);

            default: return false;

        }

    }

    /** Return true if a tree represents the null literal. */

    public static boolean isNull(JCTree tree) {

        if (tree.getTag() != JCTree.LITERAL)

            return false;

        JCLiteral lit = (JCLiteral) tree;

        return (lit.typetag == TypeTags.BOT);

    }

    /** The position of the first statement in a block, or the position of

     *  the block itself if it is empty.

     */

    public static int firstStatPos(JCTree tree) {

        if (tree.getTag() == JCTree.BLOCK && ((JCBlock) tree).stats.nonEmpty())

            return ((JCBlock) tree).stats.head.pos;

        else

            return tree.pos;

    }

    /** The end position of given tree, if it is a block with

     *  defined endpos.

     */

    public static int endPos(JCTree tree) {

        if (tree.getTag() == JCTree.BLOCK && ((JCBlock) tree).endpos != Position.NOPOS)

            return ((JCBlock) tree).endpos;

        else if (tree.getTag() == JCTree.SYNCHRONIZED)

            return endPos(((JCSynchronized) tree).body);

        else if (tree.getTag() == JCTree.TRY) {

            JCTry t = (JCTry) tree;

            return endPos((t.finalizer != null)

                          ? t.finalizer

                          : t.catchers.last().body);

        } else

            return tree.pos;

    }

    /** Get the start position for a tree node.  The start position is

     * defined to be the position of the first character of the first

     * token of the node's source text.

     * @param tree  The tree node

     */

    public static int getStartPos(JCTree tree) {

        if (tree == null)

            return Position.NOPOS;

        switch(tree.getTag()) {

        case(JCTree.APPLY):

            return getStartPos(((JCMethodInvocation) tree).meth);

        case(JCTree.ASSIGN):

            return getStartPos(((JCAssign) tree).lhs);

        case(JCTree.BITOR_ASG): case(JCTree.BITXOR_ASG): case(JCTree.BITAND_ASG):

        case(JCTree.SL_ASG): case(JCTree.SR_ASG): case(JCTree.USR_ASG):

        case(JCTree.PLUS_ASG): case(JCTree.MINUS_ASG): case(JCTree.MUL_ASG):

        case(JCTree.DIV_ASG): case(JCTree.MOD_ASG):

            return getStartPos(((JCAssignOp) tree).lhs);

        case(JCTree.OR): case(JCTree.AND): case(JCTree.BITOR):

        case(JCTree.BITXOR): case(JCTree.BITAND): case(JCTree.EQ):

        case(JCTree.NE): case(JCTree.LT): case(JCTree.GT):

        case(JCTree.LE): case(JCTree.GE): case(JCTree.SL):

        case(JCTree.SR): case(JCTree.USR): case(JCTree.PLUS):

        case(JCTree.MINUS): case(JCTree.MUL): case(JCTree.DIV):

        case(JCTree.MOD):

            return getStartPos(((JCBinary) tree).lhs);

        case(JCTree.CLASSDEF): {

            JCClassDecl node = (JCClassDecl)tree;

            if (node.mods.pos != Position.NOPOS)

                return node.mods.pos;

            break;

        }

        case(JCTree.CONDEXPR):

            return getStartPos(((JCConditional) tree).cond);

        case(JCTree.EXEC):

            return getStartPos(((JCExpressionStatement) tree).expr);

        case(JCTree.INDEXED):

            return getStartPos(((JCArrayAccess) tree).indexed);

        case(JCTree.METHODDEF): {

            JCMethodDecl node = (JCMethodDecl)tree;

            if (node.mods.pos != Position.NOPOS)

                return node.mods.pos;

            if (node.typarams.nonEmpty()) // List.nil() used for no typarams

                return getStartPos(node.typarams.head);

            return node.restype == null ? node.pos : getStartPos(node.restype);

        }

        case(JCTree.SELECT):

            return getStartPos(((JCFieldAccess) tree).selected);

        case(JCTree.TYPEAPPLY):

            return getStartPos(((JCTypeApply) tree).clazz);

        case(JCTree.TYPEARRAY):

            return getStartPos(((JCArrayTypeTree) tree).elemtype);

        case(JCTree.TYPETEST):

            return getStartPos(((JCInstanceOf) tree).expr);

        case(JCTree.POSTINC):

        case(JCTree.POSTDEC):

            return getStartPos(((JCUnary) tree).arg);

        case(JCTree.NEWCLASS): {

            JCNewClass node = (JCNewClass)tree;

            if (node.encl != null)

                return getStartPos(node.encl);

            break;

        }

        case(JCTree.VARDEF): {

            JCVariableDecl node = (JCVariableDecl)tree;

            if (node.mods.pos != Position.NOPOS) {

                return node.mods.pos;

            } else {

                return getStartPos(node.vartype);

            }

        }

        case(JCTree.ERRONEOUS): {

            JCErroneous node = (JCErroneous)tree;

            if (node.errs != null && node.errs.nonEmpty())

                return getStartPos(node.errs.head);

        }

        }

        return tree.pos;

    }

    /** The end position of given tree, given  a table of end positions generated by the parser

     */

    public static int getEndPos(JCTree tree, Map<JCTree, Integer> endPositions) {

        if (tree == null)

            return Position.NOPOS;

        if (endPositions == null) {

            // fall back on limited info in the tree

            return endPos(tree);

        }

        Integer mapPos = endPositions.get(tree);

        if (mapPos != null)

            return mapPos;

        switch(tree.getTag()) {

        case(JCTree.BITOR_ASG): case(JCTree.BITXOR_ASG): case(JCTree.BITAND_ASG):

        case(JCTree.SL_ASG): case(JCTree.SR_ASG): case(JCTree.USR_ASG):

        case(JCTree.PLUS_ASG): case(JCTree.MINUS_ASG): case(JCTree.MUL_ASG):

        case(JCTree.DIV_ASG): case(JCTree.MOD_ASG):

            return getEndPos(((JCAssignOp) tree).rhs, endPositions);

        case(JCTree.OR): case(JCTree.AND): case(JCTree.BITOR):

        case(JCTree.BITXOR): case(JCTree.BITAND): case(JCTree.EQ):

        case(JCTree.NE): case(JCTree.LT): case(JCTree.GT):

        case(JCTree.LE): case(JCTree.GE): case(JCTree.SL):

        case(JCTree.SR): case(JCTree.USR): case(JCTree.PLUS):

        case(JCTree.MINUS): case(JCTree.MUL): case(JCTree.DIV):

        case(JCTree.MOD):

            return getEndPos(((JCBinary) tree).rhs, endPositions);

        case(JCTree.CASE):

            return getEndPos(((JCCase) tree).stats.last(), endPositions);

        case(JCTree.CATCH):

            return getEndPos(((JCCatch) tree).body, endPositions);

        case(JCTree.CONDEXPR):

            return getEndPos(((JCConditional) tree).falsepart, endPositions);

        case(JCTree.FORLOOP):

            return getEndPos(((JCForLoop) tree).body, endPositions);

        case(JCTree.FOREACHLOOP):

            return getEndPos(((JCEnhancedForLoop) tree).body, endPositions);

        case(JCTree.IF): {

            JCIf node = (JCIf)tree;

            if (node.elsepart == null) {

                return getEndPos(node.thenpart, endPositions);

            } else {

                return getEndPos(node.elsepart, endPositions);

            }

        }

        case(JCTree.LABELLED):

            return getEndPos(((JCLabeledStatement) tree).body, endPositions);

        case(JCTree.MODIFIERS):

            return getEndPos(((JCModifiers) tree).annotations.last(), endPositions);

        case(JCTree.SYNCHRONIZED):

            return getEndPos(((JCSynchronized) tree).body, endPositions);

        case(JCTree.TOPLEVEL):

            return getEndPos(((JCCompilationUnit) tree).defs.last(), endPositions);

        case(JCTree.TRY): {

            JCTry node = (JCTry)tree;

            if (node.finalizer != null) {

                return getEndPos(node.finalizer, endPositions);

            } else if (!node.catchers.isEmpty()) {

                return getEndPos(node.catchers.last(), endPositions);

            } else {

                return getEndPos(node.body, endPositions);

            }

        }

        case(JCTree.WILDCARD):

            return getEndPos(((JCWildcard) tree).inner, endPositions);

        case(JCTree.TYPECAST):

            return getEndPos(((JCTypeCast) tree).expr, endPositions);

        case(JCTree.TYPETEST):

            return getEndPos(((JCInstanceOf) tree).clazz, endPositions);

        case(JCTree.POS):

        case(JCTree.NEG):

        case(JCTree.NOT):

        case(JCTree.COMPL):

        case(JCTree.PREINC):

        case(JCTree.PREDEC):

            return getEndPos(((JCUnary) tree).arg, endPositions);

        case(JCTree.WHILELOOP):

            return getEndPos(((JCWhileLoop) tree).body, endPositions);

        case(JCTree.ERRONEOUS): {

            JCErroneous node = (JCErroneous)tree;

            if (node.errs != null && node.errs.nonEmpty())

                return getEndPos(node.errs.last(), endPositions);

        }

        }

        return Position.NOPOS;

    }

    /** A DiagnosticPosition with the preferred position set to the

     *  end position of given tree, if it is a block with

     *  defined endpos.

     */

    public static DiagnosticPosition diagEndPos(final JCTree tree) {

        final int endPos = TreeInfo.endPos(tree);

        return new DiagnosticPosition() {

            public JCTree getTree() { return tree; }

            public int getStartPosition() { return TreeInfo.getStartPos(tree); }

            public int getPreferredPosition() { return endPos; }

            public int getEndPosition(Map<JCTree, Integer> endPosTable) {

                return TreeInfo.getEndPos(tree, endPosTable);

            }

        };

    }

    /** The position of the finalizer of given try/synchronized statement.

     */

    public static int finalizerPos(JCTree tree) {

        if (tree.getTag() == JCTree.TRY) {

            JCTry t = (JCTry) tree;

            return firstStatPos(t.finalizer);

        } else if (tree.getTag() == JCTree.SYNCHRONIZED) {

            return endPos(((JCSynchronized) tree).body);

        } else {

            throw new AssertionError();

        }

    }

    /** Find the position for reporting an error about a symbol, where

     *  that symbol is defined somewhere in the given tree. */

    public static int positionFor(final Symbol sym, final JCTree tree) {

        JCTree decl = declarationFor(sym, tree);

        return ((decl != null) ? decl : tree).pos;

    }

    /** Find the position for reporting an error about a symbol, where

     *  that symbol is defined somewhere in the given tree. */

    public static DiagnosticPosition diagnosticPositionFor(final Symbol sym, final JCTree tree) {

        JCTree decl = declarationFor(sym, tree);

        return ((decl != null) ? decl : tree).pos();

    }

    /** Find the declaration for a symbol, where

     *  that symbol is defined somewhere in the given tree. */

    public static JCTree declarationFor(final Symbol sym, final JCTree tree) {

        class DeclScanner extends TreeScanner {

            JCTree result = null;

            public void scan(JCTree tree) {

                if (tree!=null && result==null)

                    tree.accept(this);

            }

            public void visitTopLevel(JCCompilationUnit that) {

                if (that.packge == sym) result = that;

                else super.visitTopLevel(that);

            }

            public void visitClassDef(JCClassDecl that) {

                if (that.sym == sym) result = that;

                else super.visitClassDef(that);

            }

            public void visitMethodDef(JCMethodDecl that) {

                if (that.sym == sym) result = that;

                else super.visitMethodDef(that);

            }

            public void visitVarDef(JCVariableDecl that) {

                if (that.sym == sym) result = that;

                else super.visitVarDef(that);

            }

            public void visitTypeParameter(JCTypeParameter that) {

                if (that.type != null && that.type.tsym == sym) result = that;

                else super.visitTypeParameter(that);

            }

        }

        DeclScanner s = new DeclScanner();

        tree.accept(s);

        return s.result;

    }

    public static Env<AttrContext> scopeFor(JCTree node, JCCompilationUnit unit) {

        return scopeFor(pathFor(node, unit));

    }

    public static Env<AttrContext> scopeFor(List<JCTree> path) {

        // TODO: not implemented yet

        throw new UnsupportedOperationException("not implemented yet");

    }

    public static List<JCTree> pathFor(final JCTree node, final JCCompilationUnit unit) {

        class Result extends Error {

            static final long serialVersionUID = -5942088234594905625L;

            List<JCTree> path;

            Result(List<JCTree> path) {

                this.path = path;

            }

        }

        class PathFinder extends TreeScanner {