UnwrappedLineParser.h revision 249423 
1//===--- UnwrappedLineParser.h - Format C++ code ----------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9///
10/// \file
11/// \brief This file contains the declaration of the UnwrappedLineParser,
12/// which turns a stream of tokens into UnwrappedLines.
13///
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
17#define LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
18
19#include "clang/Basic/IdentifierTable.h"
20#include "clang/Basic/SourceManager.h"
21#include "clang/Format/Format.h"
22#include "clang/Lex/Lexer.h"
23#include <list>
24
25namespace clang {
26
27class DiagnosticsEngine;
28
29namespace format {
30
31/// \brief A wrapper around a \c Token storing information about the
32/// whitespace characters preceeding it.
33struct FormatToken {
34  FormatToken()
35      : NewlinesBefore(0), HasUnescapedNewline(false), WhiteSpaceLength(0),
36        LastNewlineOffset(0), TokenLength(0), IsFirst(false),
37        MustBreakBefore(false) {}
38
39  /// \brief The \c Token.
40  Token Tok;
41
42  /// \brief The number of newlines immediately before the \c Token.
43  ///
44  /// This can be used to determine what the user wrote in the original code
45  /// and thereby e.g. leave an empty line between two function definitions.
46  unsigned NewlinesBefore;
47
48  /// \brief Whether there is at least one unescaped newline before the \c
49  /// Token.
50  bool HasUnescapedNewline;
51
52  /// \brief The location of the start of the whitespace immediately preceeding
53  /// the \c Token.
54  ///
55  /// Used together with \c WhiteSpaceLength to create a \c Replacement.
56  SourceLocation WhiteSpaceStart;
57
58  /// \brief The length in characters of the whitespace immediately preceeding
59  /// the \c Token.
60  unsigned WhiteSpaceLength;
61
62  /// \brief The offset just past the last '\n' in this token's leading
63  /// whitespace (relative to \c WhiteSpaceStart). 0 if there is no '\n'.
64  unsigned LastNewlineOffset;
65
66  /// \brief The length of the non-whitespace parts of the token. This is
67  /// necessary because we need to handle escaped newlines that are stored
68  /// with the token.
69  unsigned TokenLength;
70
71  /// \brief Indicates that this is the first token.
72  bool IsFirst;
73
74  /// \brief Whether there must be a line break before this token.
75  ///
76  /// This happens for example when a preprocessor directive ended directly
77  /// before the token.
78  bool MustBreakBefore;
79};
80
81/// \brief An unwrapped line is a sequence of \c Token, that we would like to
82/// put on a single line if there was no column limit.
83///
84/// This is used as a main interface between the \c UnwrappedLineParser and the
85/// \c UnwrappedLineFormatter. The key property is that changing the formatting
86/// within an unwrapped line does not affect any other unwrapped lines.
87struct UnwrappedLine {
88  UnwrappedLine() : Level(0), InPPDirective(false), MustBeDeclaration(false) {
89  }
90
91  // FIXME: Don't use std::list here.
92  /// \brief The \c Tokens comprising this \c UnwrappedLine.
93  std::list<FormatToken> Tokens;
94
95  /// \brief The indent level of the \c UnwrappedLine.
96  unsigned Level;
97
98  /// \brief Whether this \c UnwrappedLine is part of a preprocessor directive.
99  bool InPPDirective;
100
101  bool MustBeDeclaration;
102};
103
104class UnwrappedLineConsumer {
105public:
106  virtual ~UnwrappedLineConsumer() {
107  }
108  virtual void consumeUnwrappedLine(const UnwrappedLine &Line) = 0;
109};
110
111class FormatTokenSource {
112public:
113  virtual ~FormatTokenSource() {
114  }
115  virtual FormatToken getNextToken() = 0;
116};
117
118class UnwrappedLineParser {
119public:
120  UnwrappedLineParser(clang::DiagnosticsEngine &Diag, const FormatStyle &Style,
121                      FormatTokenSource &Tokens,
122                      UnwrappedLineConsumer &Callback);
123
124  /// Returns true in case of a structural error.
125  bool parse();
126
127private:
128  bool parseFile();
129  bool parseLevel(bool HasOpeningBrace);
130  bool parseBlock(bool MustBeDeclaration, unsigned AddLevels = 1);
131  void parsePPDirective();
132  void parsePPDefine();
133  void parsePPUnknown();
134  void parseStructuralElement();
135  void parseBracedList();
136  void parseReturn();
137  void parseParens();
138  void parseIfThenElse();
139  void parseForOrWhileLoop();
140  void parseDoWhile();
141  void parseLabel();
142  void parseCaseLabel();
143  void parseSwitch();
144  void parseNamespace();
145  void parseAccessSpecifier();
146  void parseEnum();
147  void parseRecord();
148  void parseObjCProtocolList();
149  void parseObjCUntilAtEnd();
150  void parseObjCInterfaceOrImplementation();
151  void parseObjCProtocol();
152  void addUnwrappedLine();
153  bool eof() const;
154  void nextToken();
155  void readToken();
156  void flushComments(bool NewlineBeforeNext);
157  void pushToken(const FormatToken &Tok);
158
159  // FIXME: We are constantly running into bugs where Line.Level is incorrectly
160  // subtracted from beyond 0. Introduce a method to subtract from Line.Level
161  // and use that everywhere in the Parser.
162  OwningPtr<UnwrappedLine> Line;
163
164  // Comments are sorted into unwrapped lines by whether they are in the same
165  // line as the previous token, or not. If not, they belong to the next token.
166  // Since the next token might already be in a new unwrapped line, we need to
167  // store the comments belonging to that token.
168  SmallVector<FormatToken, 1> CommentsBeforeNextToken;
169  FormatToken FormatTok;
170  bool MustBreakBeforeNextToken;
171
172  // The parsed lines. Only added to through \c CurrentLines.
173  std::vector<UnwrappedLine> Lines;
174
175  // Preprocessor directives are parsed out-of-order from other unwrapped lines.
176  // Thus, we need to keep a list of preprocessor directives to be reported
177  // after an unwarpped line that has been started was finished.
178  std::vector<UnwrappedLine> PreprocessorDirectives;
179
180  // New unwrapped lines are added via CurrentLines.
181  // Usually points to \c &Lines. While parsing a preprocessor directive when
182  // there is an unfinished previous unwrapped line, will point to
183  // \c &PreprocessorDirectives.
184  std::vector<UnwrappedLine> *CurrentLines;
185
186  // We store for each line whether it must be a declaration depending on
187  // whether we are in a compound statement or not.
188  std::vector<bool> DeclarationScopeStack;
189
190  clang::DiagnosticsEngine &Diag;
191  const FormatStyle &Style;
192  FormatTokenSource *Tokens;
193  UnwrappedLineConsumer &Callback;
194
195  friend class ScopedLineState;
196};
197
198} // end namespace format
199} // end namespace clang
200
201#endif // LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
202