1 // Copyright 2011 Google Inc. All Rights Reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef NINJA_LEXER_H_ 16 #define NINJA_LEXER_H_ 17 18 #include "string_piece.h" 19 20 // Windows may #define ERROR. 21 #ifdef ERROR 22 #undef ERROR 23 #endif 24 25 struct EvalString; 26 27 struct Lexer { LexerLexer28 Lexer() {} 29 /// Helper ctor useful for tests. 30 explicit Lexer(const char* input); 31 32 enum Token { 33 ERROR, 34 BUILD, 35 COLON, 36 DEFAULT, 37 EQUALS, 38 IDENT, 39 INCLUDE, 40 INDENT, 41 NEWLINE, 42 PIPE, 43 PIPE2, 44 PIPEAT, 45 POOL, 46 RULE, 47 SUBNINJA, 48 TEOF, 49 }; 50 51 /// Return a human-readable form of a token, used in error messages. 52 static const char* TokenName(Token t); 53 54 /// Return a human-readable token hint, used in error messages. 55 static const char* TokenErrorHint(Token expected); 56 57 /// If the last token read was an ERROR token, provide more info 58 /// or the empty string. 59 std::string DescribeLastError(); 60 61 /// Start parsing some input. 62 void Start(StringPiece filename, StringPiece input); 63 64 /// Read a Token from the Token enum. 65 Token ReadToken(); 66 67 /// Rewind to the last read Token. 68 void UnreadToken(); 69 70 /// If the next token is \a token, read it and return true. 71 bool PeekToken(Token token); 72 73 /// Read a simple identifier (a rule or variable name). 74 /// Returns false if a name can't be read. 75 bool ReadIdent(std::string* out); 76 77 /// Read a path (complete with $escapes). 78 /// Returns false only on error, returned path may be empty if a delimiter 79 /// (space, newline) is hit. ReadPathLexer80 bool ReadPath(EvalString* path, std::string* err) { 81 return ReadEvalString(path, true, err); 82 } 83 84 /// Read the value side of a var = value line (complete with $escapes). 85 /// Returns false only on error. ReadVarValueLexer86 bool ReadVarValue(EvalString* value, std::string* err) { 87 return ReadEvalString(value, false, err); 88 } 89 90 /// Construct an error message with context. 91 bool Error(const std::string& message, std::string* err); 92 93 private: 94 /// Skip past whitespace (called after each read token/ident/etc.). 95 void EatWhitespace(); 96 97 /// Read a $-escaped string. 98 bool ReadEvalString(EvalString* eval, bool path, std::string* err); 99 100 StringPiece filename_; 101 StringPiece input_; 102 const char* ofs_; 103 const char* last_token_; 104 }; 105 106 #endif // NINJA_LEXER_H_ 107