1 //===--- FormatTokenLexer.h - Format C++ code ----------------*- C++ ----*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file contains FormatTokenLexer, which tokenizes a source file
11 /// into a token stream suitable for ClangFormat.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_LIB_FORMAT_FORMATTOKENLEXER_H
16 #define LLVM_CLANG_LIB_FORMAT_FORMATTOKENLEXER_H
17 
18 #include "Encoding.h"
19 #include "FormatToken.h"
20 #include "clang/Basic/LangOptions.h"
21 #include "clang/Basic/SourceLocation.h"
22 #include "clang/Basic/SourceManager.h"
23 #include "clang/Format/Format.h"
24 #include "llvm/ADT/MapVector.h"
25 #include "llvm/ADT/StringSet.h"
26 #include "llvm/Support/Regex.h"
27 
28 #include <stack>
29 
30 namespace clang {
31 namespace format {
32 
33 enum LexerState {
34   NORMAL,
35   TEMPLATE_STRING,
36   TOKEN_STASHED,
37 };
38 
39 class FormatTokenLexer {
40 public:
41   FormatTokenLexer(const SourceManager &SourceMgr, FileID ID, unsigned Column,
42                    const FormatStyle &Style, encoding::Encoding Encoding,
43                    llvm::SpecificBumpPtrAllocator<FormatToken> &Allocator,
44                    IdentifierTable &IdentTable);
45 
46   ArrayRef<FormatToken *> lex();
47 
48   const AdditionalKeywords &getKeywords() { return Keywords; }
49 
50 private:
51   void tryMergePreviousTokens();
52 
53   bool tryMergeLessLess();
54   bool tryMergeNSStringLiteral();
55   bool tryMergeJSPrivateIdentifier();
56   bool tryMergeCSharpStringLiteral();
57   bool tryMergeCSharpKeywordVariables();
58   bool tryMergeNullishCoalescingEqual();
59   bool tryTransformCSharpForEach();
60   bool tryMergeForEach();
61   bool tryTransformTryUsageForC();
62 
63   bool tryMergeTokens(ArrayRef<tok::TokenKind> Kinds, TokenType NewType);
64 
65   // Returns \c true if \p Tok can only be followed by an operand in JavaScript.
66   bool precedesOperand(FormatToken *Tok);
67 
68   bool canPrecedeRegexLiteral(FormatToken *Prev);
69 
70   // Tries to parse a JavaScript Regex literal starting at the current token,
71   // if that begins with a slash and is in a location where JavaScript allows
72   // regex literals. Changes the current token to a regex literal and updates
73   // its text if successful.
74   void tryParseJSRegexLiteral();
75 
76   // Handles JavaScript template strings.
77   //
78   // JavaScript template strings use backticks ('`') as delimiters, and allow
79   // embedding expressions nested in ${expr-here}. Template strings can be
80   // nested recursively, i.e. expressions can contain template strings in turn.
81   //
82   // The code below parses starting from a backtick, up to a closing backtick or
83   // an opening ${. It also maintains a stack of lexing contexts to handle
84   // nested template parts by balancing curly braces.
85   void handleTemplateStrings();
86 
87   void handleCSharpVerbatimAndInterpolatedStrings();
88 
89   void tryParsePythonComment();
90 
91   bool tryMerge_TMacro();
92 
93   bool tryMergeConflictMarkers();
94 
95   FormatToken *getStashedToken();
96 
97   FormatToken *getNextToken();
98 
99   FormatToken *FormatTok;
100   bool IsFirstToken;
101   std::stack<LexerState> StateStack;
102   unsigned Column;
103   unsigned TrailingWhitespace;
104   std::unique_ptr<Lexer> Lex;
105   LangOptions LangOpts;
106   const SourceManager &SourceMgr;
107   FileID ID;
108   const FormatStyle &Style;
109   IdentifierTable &IdentTable;
110   AdditionalKeywords Keywords;
111   encoding::Encoding Encoding;
112   llvm::SpecificBumpPtrAllocator<FormatToken> &Allocator;
113   // Index (in 'Tokens') of the last token that starts a new line.
114   unsigned FirstInLineIndex;
115   SmallVector<FormatToken *, 16> Tokens;
116 
117   llvm::SmallMapVector<IdentifierInfo *, TokenType, 8> Macros;
118 
119   bool FormattingDisabled;
120 
121   llvm::Regex MacroBlockBeginRegex;
122   llvm::Regex MacroBlockEndRegex;
123 
124   // Targets that may appear inside a C# attribute.
125   static const llvm::StringSet<> CSharpAttributeTargets;
126 
127   void readRawToken(FormatToken &Tok);
128 
129   void resetLexer(unsigned Offset);
130 };
131 
132 } // namespace format
133 } // namespace clang
134 
135 #endif
136