/*

 * Copyright (c) 2001, 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.jvm;

import java.util.*;

import com.sun.tools.javac.resources.CompilerProperties.Warnings;

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

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

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

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

import com.sun.tools.javac.tree.EndPosTable;

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

/** This class contains the CharacterRangeTable for some method

 *  and the hashtable for mapping trees or lists of trees to their

 *  ending positions.

 *

 *  <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 CRTable

implements CRTFlags {

    private final boolean crtDebug = false;

    /** The list of CRTable entries.

     */

    private ListBuffer<CRTEntry> entries = new ListBuffer<>();

    /** The hashtable for source positions.

     */

    private Map<Object,SourceRange> positions = new HashMap<>();

    /** The object for ending positions stored in the parser.

     */

    private EndPosTable endPosTable;

    /** The tree of the method this table is intended for.

     *  We should traverse this tree to get source ranges.

     */

    JCTree.JCMethodDecl methodTree;

    /** Constructor

     */

    public CRTable(JCTree.JCMethodDecl tree, EndPosTable endPosTable) {

        this.methodTree = tree;

        this.endPosTable = endPosTable;

    }

    /** Create a new CRTEntry and add it to the entries.

     *  @param tree     The tree or the list of trees for which

     *                  we are storing the code pointers.

     *  @param flags    The set of flags designating type of the entry.

     *  @param startPc  The starting code position.

     *  @param endPc    The ending code position.

     */

    public void put(Object tree, int flags, int startPc, int endPc) {

        entries.append(new CRTEntry(tree, flags, startPc, endPc));

    }

    /** Compute source positions and write CRT to the databuf.

     *  @param databuf  The buffer to write bytecodes to.

     */

    public int writeCRT(ByteBuffer databuf, Position.LineMap lineMap, Log log) {

        int crtEntries = 0;

        // compute source positions for the method

        new SourceComputer().csp(methodTree);

        for (List<CRTEntry> l = entries.toList(); l.nonEmpty(); l = l.tail) {

            CRTEntry entry = l.head;

            // eliminate entries that do not produce bytecodes:

            // for example, empty blocks and statements

            if (entry.startPc == entry.endPc)

                continue;

            SourceRange pos = positions.get(entry.tree);

            Assert.checkNonNull(pos, "CRT: tree source positions are undefined");

            if ((pos.startPos == Position.NOPOS) || (pos.endPos == Position.NOPOS))

                continue;

            if (crtDebug) {

                System.out.println("Tree: " + entry.tree + ", type:" + getTypes(entry.flags));

                System.out.print("Start: pos = " + pos.startPos + ", pc = " + entry.startPc);

            }

            // encode startPos into line/column representation

            int startPos = encodePosition(pos.startPos, lineMap, log);

            if (startPos == Position.NOPOS)

                continue;

            if (crtDebug) {

                System.out.print("End:   pos = " + pos.endPos + ", pc = " + (entry.endPc - 1));

            }

            // encode endPos into line/column representation

            int endPos = encodePosition(pos.endPos, lineMap, log);

            if (endPos == Position.NOPOS)

                continue;

            // write attribute

            databuf.appendChar(entry.startPc);

            // 'endPc - 1' because endPc actually points to start of the next command

            databuf.appendChar(entry.endPc - 1);

            databuf.appendInt(startPos);

            databuf.appendInt(endPos);

            databuf.appendChar(entry.flags);

            crtEntries++;

        }

        return crtEntries;

    }

    /** Return the number of the entries.

     */

    public int length() {

        return entries.length();

    }

    /** Return string describing flags enabled.

     */

    private String getTypes(int flags) {

        String types = "";

        if ((flags & CRT_STATEMENT)       != 0) types += " CRT_STATEMENT";

        if ((flags & CRT_BLOCK)           != 0) types += " CRT_BLOCK";

        if ((flags & CRT_ASSIGNMENT)      != 0) types += " CRT_ASSIGNMENT";

        if ((flags & CRT_FLOW_CONTROLLER) != 0) types += " CRT_FLOW_CONTROLLER";

        if ((flags & CRT_FLOW_TARGET)     != 0) types += " CRT_FLOW_TARGET";

        if ((flags & CRT_INVOKE)          != 0) types += " CRT_INVOKE";

        if ((flags & CRT_CREATE)          != 0) types += " CRT_CREATE";

        if ((flags & CRT_BRANCH_TRUE)     != 0) types += " CRT_BRANCH_TRUE";

        if ((flags & CRT_BRANCH_FALSE)    != 0) types += " CRT_BRANCH_FALSE";

        return types;

    }

    /** Source file positions in CRT are integers in the format:

     *  {@literal line-number << LINESHIFT + column-number }

     */

     private int encodePosition(int pos, Position.LineMap lineMap, Log log) {

         int line = lineMap.getLineNumber(pos);

         int col = lineMap.getColumnNumber(pos);

         int new_pos = Position.encodePosition(line, col);

         if (crtDebug) {

             System.out.println(", line = " + line + ", column = " + col +

                                ", new_pos = " + new_pos);

         }

         if (new_pos == Position.NOPOS)

             log.warning(pos, Warnings.PositionOverflow(line));

        return new_pos;

     }

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

 * Traversal methods

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

    /**

     *  This class contains methods to compute source positions for trees.

     *  Extends Tree.Visitor to traverse the abstract syntax tree.

     */

    class SourceComputer extends JCTree.Visitor {

        /** The result of the tree traversal methods.

         */

        SourceRange result;

        /** Visitor method: compute source positions for a single node.

         */

        public SourceRange csp(JCTree tree) {

            if (tree == null) return null;

            tree.accept(this);

            if (result != null) {

                positions.put(tree, result);

            }

            return result;

        }

        /** Visitor method: compute source positions for a list of nodes.

         */

        public SourceRange csp(List<? extends JCTree> trees) {

            if ((trees == null) || !(trees.nonEmpty())) return null;

            SourceRange list_sr = new SourceRange();

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

                list_sr.mergeWith(csp(l.head));

            }

            positions.put(trees, list_sr);

            return list_sr;

        }

        /**  Visitor method: compute source positions for

         *    a list of case blocks of switch statements.

         */

        public SourceRange cspCases(List<JCCase> trees) {

            if ((trees == null) || !(trees.nonEmpty())) return null;

            SourceRange list_sr = new SourceRange();

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

                list_sr.mergeWith(csp(l.head));

            }

            positions.put(trees, list_sr);

            return list_sr;

        }

        /**  Visitor method: compute source positions for

         *   a list of catch clauses in try statements.

         */

        public SourceRange cspCatchers(List<JCCatch> trees) {

            if ((trees == null) || !(trees.nonEmpty())) return null;

            SourceRange list_sr = new SourceRange();

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

                list_sr.mergeWith(csp(l.head));

            }

            positions.put(trees, list_sr);

            return list_sr;

        }

        public void visitMethodDef(JCMethodDecl tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitVarDef(JCVariableDecl tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            csp(tree.vartype);

            sr.mergeWith(csp(tree.init));

            result = sr;

        }

        public void visitSkip(JCSkip tree) {

            // endPos is the same as startPos for the empty statement

            SourceRange sr = new SourceRange(startPos(tree), startPos(tree));

            result = sr;

        }

        public void visitBlock(JCBlock tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            csp(tree.stats);    // doesn't compare because block's ending position is defined

            result = sr;

        }

        public void visitDoLoop(JCDoWhileLoop tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.body));

            sr.mergeWith(csp(tree.cond));

            result = sr;

        }

        public void visitWhileLoop(JCWhileLoop tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.cond));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitForLoop(JCForLoop tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.init));

            sr.mergeWith(csp(tree.cond));

            sr.mergeWith(csp(tree.step));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitForeachLoop(JCEnhancedForLoop tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.var));

            sr.mergeWith(csp(tree.expr));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitLabelled(JCLabeledStatement tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitSwitch(JCSwitch tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.selector));

            sr.mergeWith(cspCases(tree.cases));

            result = sr;

        }

        @Override

        public void visitSwitchExpression(JCSwitchExpression tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.selector));

            sr.mergeWith(cspCases(tree.cases));

            result = sr;

        }

        public void visitCase(JCCase tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.pats));

            sr.mergeWith(csp(tree.stats));

            result = sr;

        }

        public void visitSynchronized(JCSynchronized tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.lock));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitTry(JCTry tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.resources));

            sr.mergeWith(csp(tree.body));

            sr.mergeWith(cspCatchers(tree.catchers));

            sr.mergeWith(csp(tree.finalizer));

            result = sr;

        }

        public void visitCatch(JCCatch tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.param));

            sr.mergeWith(csp(tree.body));

            result = sr;

        }

        public void visitConditional(JCConditional tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.cond));

            sr.mergeWith(csp(tree.truepart));

            sr.mergeWith(csp(tree.falsepart));

            result = sr;

        }

        public void visitIf(JCIf tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.cond));

            sr.mergeWith(csp(tree.thenpart));

            sr.mergeWith(csp(tree.elsepart));

            result = sr;

        }

        public void visitExec(JCExpressionStatement tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.expr));

            result = sr;

        }

        public void visitBreak(JCBreak tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            result = sr;

        }

        public void visitYield(JCYield tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            result = sr;

        }

        public void visitContinue(JCContinue tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            result = sr;

        }

        public void visitReturn(JCReturn tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.expr));

            result = sr;

        }

        public void visitThrow(JCThrow tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.expr));

            result = sr;

        }

        public void visitAssert(JCAssert tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.cond));

            sr.mergeWith(csp(tree.detail));

            result = sr;

        }

        public void visitApply(JCMethodInvocation tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.meth));

            sr.mergeWith(csp(tree.args));

            result = sr;

        }

        public void visitNewClass(JCNewClass tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.encl));

            sr.mergeWith(csp(tree.clazz));

            sr.mergeWith(csp(tree.args));

            sr.mergeWith(csp(tree.def));

            result = sr;

        }

        public void visitNewArray(JCNewArray tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.elemtype));

            sr.mergeWith(csp(tree.dims));

            sr.mergeWith(csp(tree.elems));

            result = sr;

        }

        public void visitParens(JCParens tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.expr));

            result = sr;

        }

        public void visitAssign(JCAssign tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.lhs));

            sr.mergeWith(csp(tree.rhs));

            result = sr;

        }

        public void visitAssignop(JCAssignOp tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.lhs));

            sr.mergeWith(csp(tree.rhs));

            result = sr;

        }

        public void visitUnary(JCUnary tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.arg));

            result = sr;

        }

        public void visitBinary(JCBinary tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.lhs));

            sr.mergeWith(csp(tree.rhs));

            result = sr;

        }

        public void visitTypeCast(JCTypeCast tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.clazz));

            sr.mergeWith(csp(tree.expr));

            result = sr;

        }

        public void visitTypeTest(JCInstanceOf tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.expr));

            result = sr;

        }

        public void visitIndexed(JCArrayAccess tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.indexed));

            sr.mergeWith(csp(tree.index));

            result = sr;

        }

        public void visitSelect(JCFieldAccess tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.selected));

            result = sr;

        }

        public void visitIdent(JCIdent tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            result = sr;

        }

        public void visitLiteral(JCLiteral tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            result = sr;

        }

        public void visitTypeIdent(JCPrimitiveTypeTree tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            result = sr;

        }

        public void visitTypeArray(JCArrayTypeTree tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.elemtype));

            result = sr;

        }

        public void visitTypeApply(JCTypeApply tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));

            sr.mergeWith(csp(tree.clazz));

            sr.mergeWith(csp(tree.arguments));

            result = sr;

        }

        @Override

        public void visitLetExpr(LetExpr tree) {

            SourceRange sr = new SourceRange(startPos(tree), endPos(tree));