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