/*
* Copyright (c) 2015, 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 jdk.jshell;
import com.sun.tools.javac.code.Source;
import com.sun.tools.javac.parser.Scanner;
import com.sun.tools.javac.parser.ScannerFactory;
import com.sun.tools.javac.parser.Tokens.Token;
import com.sun.tools.javac.parser.Tokens.TokenKind;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.JCDiagnostic;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticFlag;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
import com.sun.tools.javac.util.Log;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.EnumMap;
import java.util.Iterator;
import jdk.jshell.SourceCodeAnalysis.Completeness;
import com.sun.source.tree.Tree;
import static jdk.jshell.CompletenessAnalyzer.TK.*;
import jdk.jshell.TaskFactory.ParseTask;
import java.util.List;
import java.util.function.Function;
import java.util.function.Supplier;
/**
* Low level scanner to determine completeness of input.
* @author Robert Field
*/
class CompletenessAnalyzer {
private final ScannerFactory scannerFactory;
private final JShell proc;
private static Completeness error() {
return Completeness.UNKNOWN; // For breakpointing
}
static class CaInfo {
CaInfo(Completeness status, int unitEndPos) {
this.status = status;
this.unitEndPos = unitEndPos;
}
final int unitEndPos;
final Completeness status;
}
CompletenessAnalyzer(JShell proc) {
this.proc = proc;
Context context = new Context();
Log log = CaLog.createLog(context);
context.put(Log.class, log);
context.put(Source.class, Source.JDK1_9);
scannerFactory = ScannerFactory.instance(context);
}
CaInfo scan(String s) {
try {
Parser parser = new Parser(
() -> new Matched(scannerFactory.newScanner(s, false)),
() -> proc.taskFactory.new ParseTask(s));
Completeness stat = parser.parseUnit();
int endPos = stat == Completeness.UNKNOWN
? s.length()
: parser.endPos();
return new CaInfo(stat, endPos);
} catch (SyntaxException ex) {
return new CaInfo(error(), s.length());
}
}
@SuppressWarnings("serial") // serialVersionUID intentionally omitted
private static class SyntaxException extends RuntimeException {
}
private static void die() {
throw new SyntaxException();
}
/**
* Subclass of Log used by compiler API to die on error and ignore
* other messages
*/
private static class CaLog extends Log {
private static CaLog createLog(Context context) {
PrintWriter pw = new PrintWriter(new StringWriter());
CaLog log = new CaLog(context, pw);
context.put(logKey, log);
return log;
}
private CaLog(Context context, PrintWriter pw) {
super(context, pw);
}
@Override
public void error(String key, Object... args) {
die();
}
@Override
public void error(DiagnosticPosition pos, String key, Object... args) {
die();
}
@Override
public void error(DiagnosticFlag flag, DiagnosticPosition pos, String key, Object... args) {
die();
}
@Override
public void error(int pos, String key, Object... args) {
die();
}
@Override
public void error(DiagnosticFlag flag, int pos, String key, Object... args) {
die();
}
@Override
public void report(JCDiagnostic diagnostic) {
// Ignore
}
}
// Location position kinds -- a token is ...
private static final int XEXPR = 0b1; // OK in expression (not first)
private static final int XDECL = 0b10; // OK in declaration (not first)
private static final int XSTMT = 0b100; // OK in statement framework (not first)
private static final int XEXPR1o = 0b1000; // OK first in expression
private static final int XDECL1o = 0b10000; // OK first in declaration
private static final int XSTMT1o = 0b100000; // OK first or only in statement framework
private static final int XEXPR1 = XEXPR1o | XEXPR; // OK in expression (anywhere)
private static final int XDECL1 = XDECL1o | XDECL; // OK in declaration (anywhere)
private static final int XSTMT1 = XSTMT1o | XSTMT; // OK in statement framework (anywhere)
private static final int XANY1 = XEXPR1o | XDECL1o | XSTMT1o; // Mask: first in statement, declaration, or expression
private static final int XTERM = 0b100000000; // Can terminate (last before EOF)
private static final int XSTART = 0b1000000000; // Boundary, must be XTERM before
private static final int XERRO = 0b10000000000; // Is an error
private static final int XBRACESNEEDED = 0b100000000000; // Expect {ANY} LBRACE
/**
* An extension of the compiler's TokenKind which adds our combined/processed
* kinds. Also associates each TK with a union of acceptable kinds of code
* position it can occupy. For example: IDENTIFER is XEXPR1|XDECL1|XTERM,
* meaning it can occur in expressions or declarations (but not in the
* framework of a statement and that can be the final (terminating) token
* in a snippet.
* <P>
* There must be a TK defined for each compiler TokenKind, an exception
* will
* be thrown if a TokenKind is defined and a corresponding TK is not. Add a
* new TK in the appropriate category. If it is like an existing category
* (e.g. a new modifier or type this may be all that is needed. If it
* is bracketing or modifies the acceptable positions of other tokens,
* please closely examine the needed changes to this scanner.
*/
static enum TK {
// Special
EOF(TokenKind.EOF, 0), //
ERROR(TokenKind.ERROR, XERRO), //
IDENTIFIER(TokenKind.IDENTIFIER, XEXPR1|XDECL1|XTERM), //
UNDERSCORE(TokenKind.UNDERSCORE, XERRO), // _
CLASS(TokenKind.CLASS, XEXPR|XDECL1|XBRACESNEEDED), // class decl (MAPPED: DOTCLASS)
MONKEYS_AT(TokenKind.MONKEYS_AT, XEXPR|XDECL1), // @
IMPORT(TokenKind.IMPORT, XDECL1|XSTART), // import -- consider declaration
SEMI(TokenKind.SEMI, XSTMT1|XTERM|XSTART), // ;
// Shouldn't see -- error
PACKAGE(TokenKind.PACKAGE, XERRO), // package
CONST(TokenKind.CONST, XERRO), // reserved keyword -- const
GOTO(TokenKind.GOTO, XERRO), // reserved keyword -- goto
CUSTOM(TokenKind.CUSTOM, XERRO), // No uses
// Declarations
ENUM(TokenKind.ENUM, XDECL1|XBRACESNEEDED), // enum
IMPLEMENTS(TokenKind.IMPLEMENTS, XDECL), // implements
INTERFACE(TokenKind.INTERFACE, XDECL1|XBRACESNEEDED), // interface
THROWS(TokenKind.THROWS, XDECL|XBRACESNEEDED), // throws
// Primarive type names
BOOLEAN(TokenKind.BOOLEAN, XEXPR1|XDECL1), // boolean
BYTE(TokenKind.BYTE, XEXPR1|XDECL1), // byte
CHAR(TokenKind.CHAR, XEXPR1|XDECL1), // char
DOUBLE(TokenKind.DOUBLE, XEXPR1|XDECL1), // double
FLOAT(TokenKind.FLOAT, XEXPR1|XDECL1), // float
INT(TokenKind.INT, XEXPR1|XDECL1), // int
LONG(TokenKind.LONG, XEXPR1|XDECL1), // long
SHORT(TokenKind.SHORT, XEXPR1|XDECL1), // short
VOID(TokenKind.VOID, XEXPR1|XDECL1), // void
// Modifiers keywords
ABSTRACT(TokenKind.ABSTRACT, XDECL1), // abstract
FINAL(TokenKind.FINAL, XDECL1), // final
NATIVE(TokenKind.NATIVE, XDECL1), // native
STATIC(TokenKind.STATIC, XDECL1), // static
STRICTFP(TokenKind.STRICTFP, XDECL1), // strictfp
PRIVATE(TokenKind.PRIVATE, XDECL1), // private
PROTECTED(TokenKind.PROTECTED, XDECL1), // protected
PUBLIC(TokenKind.PUBLIC, XDECL1), // public
TRANSIENT(TokenKind.TRANSIENT, XDECL1), // transient
VOLATILE(TokenKind.VOLATILE, XDECL1), // volatile
// Declarations and type parameters (thus expressions)
EXTENDS(TokenKind.EXTENDS, XEXPR|XDECL), // extends
COMMA(TokenKind.COMMA, XEXPR|XDECL), // ,
AMP(TokenKind.AMP, XEXPR|XDECL), // &
GT(TokenKind.GT, XEXPR|XDECL), // >
LT(TokenKind.LT, XEXPR|XDECL1), // <
LTLT(TokenKind.LTLT, XEXPR|XDECL1), // <<
GTGT(TokenKind.GTGT, XEXPR|XDECL), // >>
GTGTGT(TokenKind.GTGTGT, XEXPR|XDECL), // >>>
QUES(TokenKind.QUES, XEXPR|XDECL), // ?
DOT(TokenKind.DOT, XEXPR|XDECL), // .
STAR(TokenKind.STAR, XEXPR), // * (MAPPED: DOTSTAR)
// Statement keywords
ASSERT(TokenKind.ASSERT, XSTMT1|XSTART), // assert
BREAK(TokenKind.BREAK, XSTMT1|XTERM|XSTART), // break
CATCH(TokenKind.CATCH, XSTMT1|XSTART), // catch
CONTINUE(TokenKind.CONTINUE, XSTMT1|XTERM|XSTART), // continue
DO(TokenKind.DO, XSTMT1|XSTART), // do
ELSE(TokenKind.ELSE, XSTMT1|XTERM|XSTART), // else
FINALLY(TokenKind.FINALLY, XSTMT1|XSTART), // finally
FOR(TokenKind.FOR, XSTMT1|XSTART), // for
IF(TokenKind.IF, XSTMT1|XSTART), // if
RETURN(TokenKind.RETURN, XSTMT1|XTERM|XSTART), // return
SWITCH(TokenKind.SWITCH, XSTMT1|XSTART), // switch
SYNCHRONIZED(TokenKind.SYNCHRONIZED, XSTMT1|XDECL), // synchronized
THROW(TokenKind.THROW, XSTMT1|XSTART), // throw
TRY(TokenKind.TRY, XSTMT1|XSTART), // try
WHILE(TokenKind.WHILE, XSTMT1|XSTART), // while
// Statement keywords that we shouldn't see -- inside braces
CASE(TokenKind.CASE, XSTMT|XSTART), // case
DEFAULT(TokenKind.DEFAULT, XSTMT|XSTART), // default method, default case -- neither we should see
// Expressions (can terminate)
INTLITERAL(TokenKind.INTLITERAL, XEXPR1|XTERM), //
LONGLITERAL(TokenKind.LONGLITERAL, XEXPR1|XTERM), //
FLOATLITERAL(TokenKind.FLOATLITERAL, XEXPR1|XTERM), //
DOUBLELITERAL(TokenKind.DOUBLELITERAL, XEXPR1|XTERM), //
CHARLITERAL(TokenKind.CHARLITERAL, XEXPR1|XTERM), //
STRINGLITERAL(TokenKind.STRINGLITERAL, XEXPR1|XTERM), //
TRUE(TokenKind.TRUE, XEXPR1|XTERM), // true
FALSE(TokenKind.FALSE, XEXPR1|XTERM), // false
NULL(TokenKind.NULL, XEXPR1|XTERM), // null
THIS(TokenKind.THIS, XEXPR1|XTERM), // this -- shouldn't see
// Expressions maybe terminate //TODO handle these case separately
PLUSPLUS(TokenKind.PLUSPLUS, XEXPR1|XTERM), // ++
SUBSUB(TokenKind.SUBSUB, XEXPR1|XTERM), // --
// Expressions cannot terminate
INSTANCEOF(TokenKind.INSTANCEOF, XEXPR), // instanceof
NEW(TokenKind.NEW, XEXPR1), // new (MAPPED: COLCOLNEW)
SUPER(TokenKind.SUPER, XEXPR1|XDECL), // super -- shouldn't see as rec. But in type parameters
ARROW(TokenKind.ARROW, XEXPR), // ->
COLCOL(TokenKind.COLCOL, XEXPR), // ::
LPAREN(TokenKind.LPAREN, XEXPR), // (
RPAREN(TokenKind.RPAREN, XEXPR), // )
LBRACE(TokenKind.LBRACE, XEXPR), // {
RBRACE(TokenKind.RBRACE, XEXPR), // }
LBRACKET(TokenKind.LBRACKET, XEXPR), // [
RBRACKET(TokenKind.RBRACKET, XEXPR), // ]
ELLIPSIS(TokenKind.ELLIPSIS, XEXPR), // ...
EQ(TokenKind.EQ, XEXPR), // =
BANG(TokenKind.BANG, XEXPR1), // !
TILDE(TokenKind.TILDE, XEXPR1), // ~
COLON(TokenKind.COLON, XEXPR|XTERM), // :
EQEQ(TokenKind.EQEQ, XEXPR), // ==
LTEQ(TokenKind.LTEQ, XEXPR), // <=
GTEQ(TokenKind.GTEQ, XEXPR), // >=
BANGEQ(TokenKind.BANGEQ, XEXPR), // !=
AMPAMP(TokenKind.AMPAMP, XEXPR), // &&
BARBAR(TokenKind.BARBAR, XEXPR), // ||
PLUS(TokenKind.PLUS, XEXPR1), // +
SUB(TokenKind.SUB, XEXPR1), // -
SLASH(TokenKind.SLASH, XEXPR), // /
BAR(TokenKind.BAR, XEXPR), // |
CARET(TokenKind.CARET, XEXPR), // ^
PERCENT(TokenKind.PERCENT, XEXPR), // %
PLUSEQ(TokenKind.PLUSEQ, XEXPR), // +=
SUBEQ(TokenKind.SUBEQ, XEXPR), // -=
STAREQ(TokenKind.STAREQ, XEXPR), // *=
SLASHEQ(TokenKind.SLASHEQ, XEXPR), // /=
AMPEQ(TokenKind.AMPEQ, XEXPR), // &=
BAREQ(TokenKind.BAREQ, XEXPR), // |=
CARETEQ(TokenKind.CARETEQ, XEXPR), // ^=
PERCENTEQ(TokenKind.PERCENTEQ, XEXPR), // %=
LTLTEQ(TokenKind.LTLTEQ, XEXPR), // <<=
GTGTEQ(TokenKind.GTGTEQ, XEXPR), // >>=
GTGTGTEQ(TokenKind.GTGTGTEQ, XEXPR), // >>>=
// combined/processed kinds
UNMATCHED(XERRO),
PARENS(XEXPR1|XDECL|XSTMT|XTERM),
BRACKETS(XEXPR|XDECL|XTERM),
BRACES(XSTMT1|XEXPR|XTERM),
DOTSTAR(XDECL|XTERM), // import foo.*
COLCOLNEW(XEXPR|XTERM), // :: new
DOTCLASS(XEXPR|XTERM), // class decl and .class
;
static final EnumMap<TokenKind,TK> tokenKindToTKMap = new EnumMap<>(TokenKind.class);
final TokenKind tokenKind;
final int belongs;
Function<TK,TK> mapping;
TK(int b) {
this(null, b);
}
TK(TokenKind tokenKind, int b) {
this.tokenKind = tokenKind;
this.belongs = b;
this.mapping = null;
}
private static TK tokenKindToTK(TK prev, TokenKind kind) {
TK tk = tokenKindToTKMap.get(kind);
if (tk == null) {
System.err.printf("No corresponding %s for %s: %s\n",
TK.class.getCanonicalName(),
TokenKind.class.getCanonicalName(),
kind);
throw new InternalError("No corresponding TK for TokenKind: " + kind);
}
return tk.mapping != null
? tk.mapping.apply(prev)
: tk;
}
boolean isOkToTerminate() {
return (belongs & XTERM) != 0;
}
boolean isExpression() {
return (belongs & XEXPR) != 0;
}
boolean isDeclaration() {
return (belongs & XDECL) != 0;
}
boolean isError() {
return (belongs & XERRO) != 0;
}
boolean isStart() {
return (belongs & XSTART) != 0;
}
boolean isBracesNeeded() {
return (belongs & XBRACESNEEDED) != 0;
}
/**
* After construction, check that all compiler TokenKind values have
* corresponding TK values.
*/
static {
for (TK tk : TK.values()) {
if (tk.tokenKind != null) {
tokenKindToTKMap.put(tk.tokenKind, tk);
}
}
for (TokenKind kind : TokenKind.values()) {
tokenKindToTK(null, kind); // assure they can be retrieved without error
}
// Mappings of disambiguated contexts
STAR.mapping = prev -> prev == DOT ? DOTSTAR : STAR;
NEW.mapping = prev -> prev == COLCOL ? COLCOLNEW : NEW;
CLASS.mapping = prev -> prev == DOT ? DOTCLASS : CLASS;
}
}
/**
* A completeness scanner token.
*/
private static class CT {
/** The token kind */
public final TK kind;
/** The end position of this token */
public final int endPos;
/** The error message **/
public final String message;
private CT(TK tk, Token tok, String msg) {
this.kind = tk;
this.endPos = tok.endPos;
this.message = msg;
//throw new InternalError(msg); /* for debugging */
}
private CT(TK tk, Token tok) {
this.kind = tk;
this.endPos = tok.endPos;
this.message = null;
}
private CT(TK tk, int endPos) {
this.kind = tk;
this.endPos = endPos;
this.message = null;
}
}
/**
* Look for matching tokens (like parens) and other special cases, like "new"
*/
private static class Matched implements Iterator<CT> {
private final Scanner scanner;
private Token current;
private CT prevCT;
private CT currentCT;
private final Deque<Token> stack = new ArrayDeque<>();
Matched(Scanner scanner) {
this.scanner = scanner;
advance();
prevCT = currentCT = new CT(SEMI, 0); // So is valid for testing
}
@Override
public boolean hasNext() {
return currentCT.kind != EOF;
}
private Token advance() {
Token prev = current;
scanner.nextToken();
current = scanner.token();
return prev;
}
@Override
public CT next() {
prevCT = currentCT;
currentCT = nextCT();
return currentCT;
}
private CT match(TK tk, TokenKind open) {
Token tok = advance();
db("match desired-tk=%s, open=%s, seen-tok=%s", tk, open, tok.kind);
if (stack.isEmpty()) {
return new CT(ERROR, tok, "Encountered '" + tok + "' with no opening '" + open + "'");
}
Token p = stack.pop();
if (p.kind != open) {
return new CT(ERROR, tok, "No match for '" + p + "' instead encountered '" + tok + "'");
}
return new CT(tk, tok);
}
private void db(String format, Object ... args) {
// System.err.printf(format, args);
// System.err.printf(" -- stack(");
// if (stack.isEmpty()) {
//
// } else {
// for (Token tok : stack) {
// System.err.printf("%s ", tok.kind);
// }
// }
// System.err.printf(") current=%s / currentCT=%s\n", current.kind, currentCT.kind);
}
/**
* @return the next scanner token
*/
private CT nextCT() {
// TODO Annotations?
TK prevTK = currentCT.kind;
while (true) {
db("nextCT");
CT ct;
switch (current.kind) {
case EOF:
db("eof");
if (stack.isEmpty()) {
ct = new CT(EOF, current);
} else {
TokenKind unmatched = stack.pop().kind;
stack.clear(); // So we will get EOF next time
ct = new CT(UNMATCHED, current, "Unmatched " + unmatched);
}
break;
case LPAREN:
case LBRACE:
case LBRACKET:
stack.push(advance());
prevTK = SEMI; // new start
continue;
case RPAREN:
ct = match(PARENS, TokenKind.LPAREN);
break;
case RBRACE:
ct = match(BRACES, TokenKind.LBRACE);
break;
case RBRACKET:
ct = match(BRACKETS, TokenKind.LBRACKET);
break;
default:
ct = new CT(TK.tokenKindToTK(prevTK, current.kind), advance());
break;
}
// Detect an error if we are at starting position and the last
// token wasn't a terminating one. Special case: within braces,
// comma can proceed semicolon, e.g. the values list in enum
if (ct.kind.isStart() && !prevTK.isOkToTerminate() && prevTK != COMMA) {
return new CT(ERROR, current, "No '" + prevTK + "' before '" + ct.kind + "'");
}
if (stack.isEmpty() || ct.kind.isError()) {
return ct;
}
prevTK = ct.kind;
}
}
}
/**
* Fuzzy parser based on token kinds
*/
private static class Parser {
private final Supplier<Matched> matchedFactory;
private final Supplier<ParseTask> parseFactory;
private Matched in;
private CT token;
private Completeness checkResult;
Parser(Supplier<Matched> matchedFactory, Supplier<ParseTask> parseFactory) {
this.matchedFactory = matchedFactory;
this.parseFactory = parseFactory;
resetInput();
}
final void resetInput() {
this.in = matchedFactory.get();
nextToken();
}
final void nextToken() {
in.next();
token = in.currentCT;
}
boolean shouldAbort(TK tk) {
if (token.kind == tk) {
nextToken();
return false;
}
switch (token.kind) {
case EOF:
checkResult = ((tk == SEMI) && in.prevCT.kind.isOkToTerminate())
? Completeness.COMPLETE_WITH_SEMI
: Completeness.DEFINITELY_INCOMPLETE;
return true;
case UNMATCHED:
checkResult = Completeness.DEFINITELY_INCOMPLETE;
return true;
default:
checkResult = error();
return true;
}
}
Completeness lastly(TK tk) {
if (shouldAbort(tk)) return checkResult;
return Completeness.COMPLETE;
}
Completeness optionalFinalSemi() {
if (!shouldAbort(SEMI)) return Completeness.COMPLETE;
if (checkResult == Completeness.COMPLETE_WITH_SEMI) return Completeness.COMPLETE;
return checkResult;
}
boolean shouldAbort(Completeness flags) {
checkResult = flags;
return flags != Completeness.COMPLETE;
}
public int endPos() {
return in.prevCT.endPos;
}
public Completeness parseUnit() {
//System.err.printf("%s: belongs %o XANY1 %o\n", token.kind, token.kind.belongs, token.kind.belongs & XANY1);
switch (token.kind.belongs & XANY1) {
case XEXPR1o:
return parseExpressionOptionalSemi();
case XSTMT1o: {
Completeness stat = parseSimpleStatement();
return stat==null? error() : stat;
}
case XDECL1o:
return parseDeclaration();
case XSTMT1o | XDECL1o:
case XEXPR1o | XDECL1o:
return disambiguateDeclarationVsExpression();
case 0:
if ((token.kind.belongs & XERRO) != 0) {
return parseExpressionStatement(); // Let this gen the status
}
return error();
default:
throw new InternalError("Case not covered " + token.kind.belongs + " in " + token.kind);
}
}
public Completeness parseDeclaration() {
boolean isImport = token.kind == IMPORT;
boolean isBracesNeeded = false;
while (token.kind.isDeclaration()) {
isBracesNeeded |= token.kind.isBracesNeeded();
nextToken();
}
switch (token.kind) {
case EQ:
nextToken();
return parseExpressionStatement();
case BRACES:
case SEMI:
nextToken();
return Completeness.COMPLETE;
case UNMATCHED:
nextToken();
return Completeness.DEFINITELY_INCOMPLETE;
case EOF:
switch (in.prevCT.kind) {
case BRACES:
case SEMI:
return Completeness.COMPLETE;
case IDENTIFIER:
return isBracesNeeded
? Completeness.DEFINITELY_INCOMPLETE
: Completeness.COMPLETE_WITH_SEMI;
case BRACKETS:
return Completeness.COMPLETE_WITH_SEMI;
case DOTSTAR:
if (isImport) {
return Completeness.COMPLETE_WITH_SEMI;
} else {
return Completeness.UNKNOWN;
}
default:
return Completeness.DEFINITELY_INCOMPLETE;
}
default:
return error();
}
}
public Completeness disambiguateDeclarationVsExpression() {
// String folding messes up position information.
ParseTask pt = parseFactory.get();
List<? extends Tree> units = pt.units();
if (units.isEmpty()) {
return error();
}
Tree unitTree = units.get(0);
switch (unitTree.getKind()) {
case EXPRESSION_STATEMENT:
return parseExpressionOptionalSemi();
case LABELED_STATEMENT:
if (shouldAbort(IDENTIFIER)) return checkResult;
if (shouldAbort(COLON)) return checkResult;
return parseStatement();
case VARIABLE:
case IMPORT:
case CLASS:
case ENUM:
case ANNOTATION_TYPE:
case INTERFACE:
case METHOD:
return parseDeclaration();
default:
return error();
}
}
public Completeness parseExpressionStatement() {
if (shouldAbort(parseExpression())) return checkResult;
return lastly(SEMI);
}
public Completeness parseExpressionOptionalSemi() {
if (shouldAbort(parseExpression())) return checkResult;
return optionalFinalSemi();
}
public Completeness parseExpression() {
while (token.kind.isExpression())
nextToken();
return Completeness.COMPLETE;
}
public Completeness parseStatement() {
Completeness stat = parseSimpleStatement();
if (stat == null) {
return parseExpressionStatement();
}
return stat;
}
/**
* Statement = Block | IF ParExpression Statement [ELSE Statement] | FOR
* "(" ForInitOpt ";" [Expression] ";" ForUpdateOpt ")" Statement | FOR
* "(" FormalParameter : Expression ")" Statement | WHILE ParExpression
* Statement | DO Statement WHILE ParExpression ";" | TRY Block (
* Catches | [Catches] FinallyPart ) | TRY "(" ResourceSpecification
* ";"opt ")" Block [Catches] [FinallyPart] | SWITCH ParExpression "{"
* SwitchBlockStatementGroups "}" | SYNCHRONIZED ParExpression Block |
* RETURN [Expression] ";" | THROW Expression ";" | BREAK [Ident] ";" |
* CONTINUE [Ident] ";" | ASSERT Expression [ ":" Expression ] ";" | ";"
*/
public Completeness parseSimpleStatement() {
switch (token.kind) {
case BRACES:
return lastly(BRACES);
case IF: {
nextToken();
if (shouldAbort(PARENS)) return checkResult;
Completeness thenpart = parseStatement();
if (shouldAbort(thenpart)) return thenpart;
if (token.kind == ELSE) {
nextToken();
return parseStatement();
}
return thenpart;
}
case FOR: {
nextToken();
if (shouldAbort(PARENS)) return checkResult;
if (shouldAbort(parseStatement())) return checkResult;
return Completeness.COMPLETE;
}
case WHILE: {
nextToken();
if (shouldAbort(PARENS)) return error();
return parseStatement();
}
case DO: {
nextToken();
switch (parseStatement()) {
case DEFINITELY_INCOMPLETE:
case CONSIDERED_INCOMPLETE:
case COMPLETE_WITH_SEMI:
return Completeness.DEFINITELY_INCOMPLETE;
case UNKNOWN:
return error();
case COMPLETE:
break;
}
if (shouldAbort(WHILE)) return checkResult;
if (shouldAbort(PARENS)) return checkResult;
return lastly(SEMI);
}
case TRY: {
boolean hasResources = false;
nextToken();
if (token.kind == PARENS) {
nextToken();
hasResources = true;
}
if (shouldAbort(BRACES)) return checkResult;
if (token.kind == CATCH || token.kind == FINALLY) {
while (token.kind == CATCH) {
if (shouldAbort(CATCH)) return checkResult;
if (shouldAbort(PARENS)) return checkResult;
if (shouldAbort(BRACES)) return checkResult;
}
if (token.kind == FINALLY) {
if (shouldAbort(FINALLY)) return checkResult;
if (shouldAbort(BRACES)) return checkResult;
}
} else if (!hasResources) {
if (token.kind == EOF) {
return Completeness.DEFINITELY_INCOMPLETE;
} else {
return error();
}
}
return Completeness.COMPLETE;
}
case SWITCH: {
nextToken();
if (shouldAbort(PARENS)) return checkResult;
return lastly(BRACES);
}
case SYNCHRONIZED: {
nextToken();
if (shouldAbort(PARENS)) return checkResult;
return lastly(BRACES);
}
case THROW: {
nextToken();
if (shouldAbort(parseExpression())) return checkResult;
return lastly(SEMI);
}
case SEMI:
return lastly(SEMI);
case ASSERT:
nextToken();
// Crude expression parsing just happily eats the optional colon
return parseExpressionStatement();
case RETURN:
case BREAK:
case CONTINUE:
nextToken();
return parseExpressionStatement();
// What are these doing here?
case ELSE:
case FINALLY:
case CATCH:
return error();
case EOF:
return Completeness.CONSIDERED_INCOMPLETE;
default:
return null;
}
}
}
}