ExpressionParser.java revision 4ba16229a40e9758db86d4fb1df5119fdcb8aa2a 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.databinding.tool;
18
19import org.antlr.v4.runtime.ANTLRInputStream;
20import org.antlr.v4.runtime.BaseErrorListener;
21import org.antlr.v4.runtime.CommonTokenStream;
22import org.antlr.v4.runtime.ParserRuleContext;
23import org.antlr.v4.runtime.RecognitionException;
24import org.antlr.v4.runtime.Recognizer;
25import org.antlr.v4.runtime.Token;
26import org.antlr.v4.runtime.misc.Nullable;
27import org.antlr.v4.runtime.tree.ErrorNode;
28import org.antlr.v4.runtime.tree.ParseTreeListener;
29import org.antlr.v4.runtime.tree.TerminalNode;
30
31import android.databinding.parser.BindingExpressionLexer;
32import android.databinding.parser.BindingExpressionParser;
33import android.databinding.tool.expr.Expr;
34import android.databinding.tool.expr.ExprModel;
35import android.databinding.tool.processing.ErrorMessages;
36import android.databinding.tool.store.Location;
37import android.databinding.tool.util.L;
38import android.databinding.tool.util.Preconditions;
39
40import java.util.ArrayList;
41import java.util.List;
42
43public class ExpressionParser {
44    final ExprModel mModel;
45    final ExpressionVisitor visitor;
46
47    public ExpressionParser(ExprModel model) {
48        mModel = model;
49        visitor = new ExpressionVisitor(mModel);
50    }
51
52    public Expr parse(String input, @Nullable Location locationInFile) {
53        ANTLRInputStream inputStream = new ANTLRInputStream(input);
54        BindingExpressionLexer lexer = new BindingExpressionLexer(inputStream);
55        CommonTokenStream tokenStream = new CommonTokenStream(lexer);
56        final BindingExpressionParser parser = new BindingExpressionParser(tokenStream);
57        parser.addErrorListener(new BaseErrorListener() {
58            @Override
59            public <T extends Token> void syntaxError(Recognizer<T, ?> recognizer,
60                    @Nullable T offendingSymbol, int line, int charPositionInLine, String msg,
61                    @Nullable RecognitionException e) {
62                L.e(ErrorMessages.SYNTAX_ERROR, msg);
63            }
64        });
65        BindingExpressionParser.BindingSyntaxContext root = parser.bindingSyntax();
66        try {
67            mModel.setCurrentLocationInFile(locationInFile);
68            visitor.setParseTreeListener(new ParseTreeListener() {
69                List<ParserRuleContext> mStack = new ArrayList<ParserRuleContext>();
70                @Override
71                public void visitTerminal(TerminalNode node) {
72                }
73
74                @Override
75                public void visitErrorNode(ErrorNode node) {
76                }
77
78                @Override
79                public void enterEveryRule(ParserRuleContext ctx) {
80                    mStack.add(ctx);
81                    mModel.setCurrentParserContext(ctx);
82                }
83
84                @Override
85                public void exitEveryRule(ParserRuleContext ctx) {
86                    Preconditions.check(ctx == mStack.get(mStack.size() - 1),
87                            "Inconsistent exit from context. Received %s, expecting %s",
88                            ctx.toInfoString(parser),
89                            mStack.get(mStack.size() - 1).toInfoString(parser));
90                    mStack.remove(mStack.size() - 1);
91                    if (mStack.size() > 0) {
92                        mModel.setCurrentParserContext(mStack.get(mStack.size() - 1));
93                    } else {
94                        mModel.setCurrentParserContext(null);
95                    }
96                }
97            });
98            return root.accept(visitor);
99        } finally {
100            mModel.setCurrentLocationInFile(null);
101        }
102    }
103
104    public ExprModel getModel() {
105        return mModel;
106    }
107}
108