pretty.java

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/*
 * Copyright 1999-2006 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.tools.javac.tree;

import java.io.*;
import java.util.*;

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

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

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

/** Prints out a tree as an indented Java source program.
 *
 *  <p><b>This is NOT part of any API supported by Sun Microsystems.  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 Pretty extends JCTree.Visitor {

    public Pretty(Writer out, boolean sourceOutput) {
        this.out = out;
        this.sourceOutput = sourceOutput;
    }

    /** Set when we are producing source output.  If we're not
     *  producing source output, we can sometimes give more detail in
     *  the output even though that detail would not be valid java
     *  soruce.
     */
    private final boolean sourceOutput;

    /** The output stream on which trees are printed.
     */
    Writer out;

    /** Indentation width (can be reassigned from outside).
     */
    public int width = 4;

    /** The current left margin.
     */
    int lmargin = 0;

    /** The enclosing class name.
     */
    Name enclClassName;

    /** A hashtable mapping trees to their documentation comments
     *  (can be null)
     */
    Map<JCTree, String> docComments = null;

    /** Align code to be indented to left margin.
     */
    void align() throws IOException {
        for (int i = 0; i < lmargin; i++) out.write(" ");
    }

    /** Increase left margin by indentation width.
     */
    void indent() {
        lmargin = lmargin + width;
    }

    /** Decrease left margin by indentation width.
     */
    void undent() {
        lmargin = lmargin - width;
    }

    /** Enter a new precedence level. Emit a `(' if new precedence level
     *  is less than precedence level so far.
     *  @param contextPrec    The precedence level in force so far.
     *  @param ownPrec        The new precedence level.
     */
    void open(int contextPrec, int ownPrec) throws IOException {
        if (ownPrec < contextPrec) out.write("(");
    }

    /** Leave precedence level. Emit a `(' if inner precedence level
     *  is less than precedence level we revert to.
     *  @param contextPrec    The precedence level we revert to.
     *  @param ownPrec        The inner precedence level.
     */
    void close(int contextPrec, int ownPrec) throws IOException {
        if (ownPrec < contextPrec) out.write(")");
    }

    /** Print string, replacing all non-ascii character with unicode escapes.
     */
    public void print(Object s) throws IOException {
        out.write(Convert.escapeUnicode(s.toString()));
    }

    /** Print new line.
     */
    public void println() throws IOException {
        out.write(lineSep);
    }

    String lineSep = System.getProperty("line.separator");

    /**************************************************************************
     * Traversal methods
     *************************************************************************/

    /** Exception to propogate IOException through visitXXX methods */
    private static class UncheckedIOException extends Error {
	static final long serialVersionUID = -4032692679158424751L;
        UncheckedIOException(IOException e) {
            super(e.getMessage(), e);
        }
    }

    /** Visitor argument: the current precedence level.
     */
    int prec;

    /** Visitor method: print expression tree.
     *  @param prec  The current precedence level.
     */
    public void printExpr(JCTree tree, int prec) throws IOException {
        int prevPrec = this.prec;
        try {
            this.prec = prec;
            if (tree == null) print("/*missing*/");
            else {
                tree.accept(this);
            }
        } catch (UncheckedIOException ex) {
            IOException e = new IOException(ex.getMessage());
            e.initCause(ex);
            throw e;
        } finally {
            this.prec = prevPrec;
        }
    }

    /** Derived visitor method: print expression tree at minimum precedence level
     *  for expression.
     */
    public void printExpr(JCTree tree) throws IOException {
        printExpr(tree, TreeInfo.noPrec);
    }

    /** Derived visitor method: print statement tree.
     */
    public void printStat(JCTree tree) throws IOException {
        printExpr(tree, TreeInfo.notExpression);
    }

    /** Derived visitor method: print list of expression trees, separated by given string.
     *  @param sep the separator string
     */
    public <T extends JCTree> void printExprs(List<T> trees, String sep) throws IOException {
        if (trees.nonEmpty()) {
            printExpr(trees.head);
            for (List<T> l = trees.tail; l.nonEmpty(); l = l.tail) {
                print(sep);
                printExpr(l.head);
            }
        }
    }

    /** Derived visitor method: print list of expression trees, separated by commas.
     */
    public <T extends JCTree> void printExprs(List<T> trees) throws IOException {
        printExprs(trees, ", ");
    }

    /** Derived visitor method: print list of statements, each on a separate line.
     */
    public void printStats(List<? extends JCTree> trees) throws IOException {
        for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail) {
            align();
            printStat(l.head);
            println();
        }
    }

    /** Print a set of modifiers.
     */
    public void printFlags(long flags) throws IOException {
        if ((flags & SYNTHETIC) != 0) print("/*synthetic*/ ");
        print(TreeInfo.flagNames(flags));
        if ((flags & StandardFlags) != 0) print(" ");
        if ((flags & ANNOTATION) != 0) print("@");
    }

    public void printAnnotations(List<JCAnnotation> trees) throws IOException {
        for (List<JCAnnotation> l = trees; l.nonEmpty(); l = l.tail) {
            printStat(l.head);
            println();
            align();
        }
    }

    /** Print documentation comment, if it exists
     *  @param tree    The tree for which a documentation comment should be printed.
     */
    public void printDocComment(JCTree tree) throws IOException {
        if (docComments != null) {
            String dc = docComments.get(tree);
            if (dc != null) {
                print("/**"); println();
                int pos = 0;
                int endpos = lineEndPos(dc, pos);
                while (pos < dc.length()) {
                    align();
                    print(" *");
                    if (pos < dc.length() && dc.charAt(pos) > ' ') print(" ");
                    print(dc.substring(pos, endpos)); println();
                    pos = endpos + 1;
                    endpos = lineEndPos(dc, pos);
                }
                align(); print(" */"); println();
                align();
            }
        }
    }
//where
    static int lineEndPos(String s, int start) {
        int pos = s.indexOf('\n', start);
        if (pos < 0) pos = s.length();
        return pos;
    }

    /** If type parameter list is non-empty, print it enclosed in "<...>" brackets.
     */
    public void printTypeParameters(List<JCTypeParameter> trees) throws IOException {
        if (trees.nonEmpty()) {
            print("<");
            printExprs(trees);
            print(">");
        }
    }

    /** Print a block.
     */
    public void printBlock(List<? extends JCTree> stats) throws IOException {
        print("{");
        println();
        indent();
        printStats(stats);
        undent();
        align();
        print("}");
    }

    /** Print a block.
     */
    public void printEnumBody(List<JCTree> stats) throws IOException {
        print("{");
        println();
        indent();
        boolean first = true;
        for (List<JCTree> l = stats; l.nonEmpty(); l = l.tail) {
            if (isEnumerator(l.head)) {
                if (!first) {
                    print(",");
                    println();
                }
                align();
                printStat(l.head);
                first = false;
            }
        }
        print(";");
        println();
        for (List<JCTree> l = stats; l.nonEmpty(); l = l.tail) {
            if (!isEnumerator(l.head)) {
                align();
                printStat(l.head);
                println();
            }
        }
        undent();
        align();
        print("}");
    }

    /** Is the given tree an enumerator definition? */
    boolean isEnumerator(JCTree t) {
        return t.getTag() == JCTree.VARDEF && (((JCVariableDecl) t).mods.flags & ENUM) != 0;
    }

    /** Print unit consisting of package clause and import statements in toplevel,
     *  followed by class definition. if class definition == null,
     *  print all definitions in toplevel.
     *  @param tree     The toplevel tree
     *  @param cdef     The class definition, which is assumed to be part of the
     *                  toplevel tree.
     */
    public void printUnit(JCCompilationUnit tree, JCClassDecl cdef) throws IOException {
        docComments = tree.docComments;
        printDocComment(tree);
        if (tree.pid != null) {
            print("package ");
            printExpr(tree.pid);
            print(";");
            println();
        }
        boolean firstImport = true;
        for (List<JCTree> l = tree.defs;
        l.nonEmpty() && (cdef == null || l.head.getTag() == JCTree.IMPORT);
        l = l.tail) {
            if (l.head.getTag() == JCTree.IMPORT) {
                JCImport imp = (JCImport)l.head;
                Name name = TreeInfo.name(imp.qualid);
                if (name == name.table.asterisk ||
                        cdef == null ||
                        isUsed(TreeInfo.symbol(imp.qualid), cdef)) {
                    if (firstImport) {
                        firstImport = false;
                        println();
                    }
                    printStat(imp);
                }
            } else {
                printStat(l.head);
            }
        }
        if (cdef != null) {
            printStat(cdef);
            println();
        }
    }
    // where
    boolean isUsed(final Symbol t, JCTree cdef) {
        class UsedVisitor extends TreeScanner {
            public void scan(JCTree tree) {
                if (tree!=null && !result) tree.accept(this);
            }
            boolean result = false;
            public void visitIdent(JCIdent tree) {
                if (tree.sym == t) result = true;
            }
        }
        UsedVisitor v = new UsedVisitor();
        v.scan(cdef);
        return v.result;
    }

    /**************************************************************************
     * Visitor methods
     *************************************************************************/

    public void visitTopLevel(JCCompilationUnit tree) {
        try {
            printUnit(tree, null);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    public void visitImport(JCImport tree) {
        try {
            print("import ");
            if (tree.staticImport) print("static ");
            printExpr(tree.qualid);
            print(";");
            println();
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }

    public void visitClassDef(JCClassDecl tree) {
        try {
            println(); align();
            printDocComment(tree);
            printAnnotations(tree.mods.annotations);
            printFlags(tree.mods.flags & ~INTERFACE);
            Name enclClassNamePrev = enclClassName;
            enclClassName = tree.name;
            if ((tree.mods.flags & INTERFACE) != 0) {
                print("interface " + tree.name);
                printTypeParameters(tree.typarams);
                if (tree.implementing.nonEmpty()) {
                    print(" extends ");