156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson/* 256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Copyright (C) 2010 Google Inc. 356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * 456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Licensed under the Apache License, Version 2.0 (the "License"); 556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * you may not use this file except in compliance with the License. 656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * You may obtain a copy of the License at 756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * 856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * http://www.apache.org/licenses/LICENSE-2.0 956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * 1056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Unless required by applicable law or agreed to in writing, software 1156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * distributed under the License is distributed on an "AS IS" BASIS, 1256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 1356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * See the License for the specific language governing permissions and 1456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * limitations under the License. 1556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson */ 1656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 1756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonpackage com.google.clearsilver.jsilver.syntax; 1856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 1956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.autoescape.EscapeMode; 2056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.exceptions.JSilverBadSyntaxException; 2156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.exceptions.JSilverIOException; 2256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.syntax.lexer.Lexer; 2356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.syntax.lexer.LexerException; 2456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.syntax.node.Start; 2556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.syntax.node.Switch; 2656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.syntax.parser.Parser; 2756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport com.google.clearsilver.jsilver.syntax.parser.ParserException; 2856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 2956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport java.io.IOException; 3056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport java.io.PushbackReader; 3156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport java.io.Reader; 3256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonimport java.util.Arrays; 3356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 3456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson/** 3556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Parses a JSilver text template into an abstract syntax tree (AST). 3656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <p/> 3756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Acts as a facade around SableCC generated code. The simplest way to process the resulting tree is 3856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * to use a visitor by extending 3956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * {@link com.google.clearsilver.jsilver.syntax.analysis.DepthFirstAdapter} and passing it to 4056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * {@link Start#apply(com.google.clearsilver.jsilver.syntax.node.Switch)}. 4156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <p/> 4256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <h3>Example:</h3> 4356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * 4456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <pre> 4556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * SyntaxTreeBuilder builder = new SyntaxTreeBuilder(); 4656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Start tree = builder.parse(myTemplate, "some-template.cs"); 4756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * // Dump out the tree 4856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * tree.apply(new SyntaxTreeDumper(System.out)); 4956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * </pre> 5056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * 5156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson */ 5256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodsonpublic class SyntaxTreeBuilder { 5356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 5456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson public SyntaxTreeBuilder() {} 5556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 5656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson /** 5756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Size of buffer in PushbackReader... needs to be large enough to parse CS opening tag and push 5856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * back if it is not valid. e.g. "<?csX" : not a tag, so pushback. 5956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson */ 6056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson private static final int PUSHBACK_SIZE = "<?cs ".length(); 6156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 6256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson /** 6356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Syntax tree optimizers, declared in the order they must be applied: 6456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <ol> 6556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <li>Type resultion makes the abstract tree concrete and must come first. 6656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <li>Sequence optimization simplifies the tree and should come before most other optimizations. 6756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <li>Inline rewriting to remove data nodes from 'inline' sections. This should come before any 6856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * optimization of variables. 6956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * <li>Var optimization simplifies complex var expressions and must come after both type 7056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * resolution and sequence optimization. 7156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * </ol> 7256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson */ 7356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson protected final Switch typeResolver = new TypeResolver(); 7456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson protected final Switch sequenceOptimizer = new SequenceOptimizer(); 7556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson protected final Switch inlineRewriter = new InlineRewriter(); 7656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson protected final Switch varOptimizer = new VarOptimizer(Arrays.asList("html", "js", "url")); 7756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 7856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson /** 7956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * Perform any additional processing on the tree. EscapeMode and templateName are required by 8056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * AutoEscaper. 8156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * 8256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * @param root The AST to post process. 8356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * @param escapeMode The escaping mode to apply to the given AST. If this is not 8456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * EscapeMode.ESCAPE_NONE, AutoEscaper will be called on the AST. 8556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * @param templateName The name of template being processed. Passed to AutoEscaper, which uses it 8656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * when displaying error messages. 8756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson */ 8856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson protected void process(Start root, EscapeMode escapeMode, String templateName) { 8956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson root.apply(typeResolver); 9056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson root.apply(sequenceOptimizer); 9156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson root.apply(inlineRewriter); 9256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson // Temporarily disabled ('cos it doesn't quite work) 9356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson // root.apply(varOptimizer); 9456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 9556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson if (!escapeMode.equals(EscapeMode.ESCAPE_NONE)) { 9656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson // AutoEscaper contains per-AST context like HTML parser object. 9756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson // Therefore, instantiating a new AutoEscaper each time. 9856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson root.apply(new AutoEscaper(escapeMode, templateName)); 9956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } 10056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } 10156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 10256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson /** 10356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * @param templateName Used for meaningful error messages. 10456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson * @param escapeMode Run {@link AutoEscaper} on the abstract syntax tree created from template. 10556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson */ 10656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson public TemplateSyntaxTree parse(Reader input, String templateName, EscapeMode escapeMode) 10756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson throws JSilverIOException, JSilverBadSyntaxException { 10856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson try { 10956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson PushbackReader pushbackReader = new PushbackReader(input, PUSHBACK_SIZE); 11056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson Lexer lexer = new Lexer(pushbackReader); 11156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson Parser parser = new Parser(lexer); 11256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson Start root = parser.parse(); 11356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson process(root, escapeMode, templateName); 11456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson return new TemplateSyntaxTree(root); 11556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } catch (IOException exception) { 11656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson throw new JSilverIOException(exception); 11756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } catch (ParserException exception) { 11856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson throw new JSilverBadSyntaxException(exception.getMessage(), exception.getToken().getText(), 11956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson templateName, exception.getToken().getLine(), exception.getToken().getPos(), exception); 12056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } catch (LexerException exception) { 12156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson throw new JSilverBadSyntaxException(exception.getMessage(), null, templateName, 12256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson JSilverBadSyntaxException.UNKNOWN_POSITION, JSilverBadSyntaxException.UNKNOWN_POSITION, 12356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson exception); 12456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } 12556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson } 12656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson} 127