RAIIObjectsForParser.h revision 200583 
1//===--- RAIIObjectsForParser.h - RAII helpers for the parser ---*- 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// This file defines and implements the some simple RAII objects that are used
11// by the parser to manage bits in recursion.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_PARSE_RAII_OBJECTS_FOR_PARSER_H
16#define LLVM_CLANG_PARSE_RAII_OBJECTS_FOR_PARSER_H
17
18#include "clang/Parse/ParseDiagnostic.h"
19
20namespace clang {
21  // TODO: move ParsingDeclRAIIObject here.
22  // TODO: move ParsingClassDefinition here.
23  // TODO: move TentativeParsingAction here.
24
25
26  /// ExtensionRAIIObject - This saves the state of extension warnings when
27  /// constructed and disables them.  When destructed, it restores them back to
28  /// the way they used to be.  This is used to handle __extension__ in the
29  /// parser.
30  class ExtensionRAIIObject {
31    void operator=(const ExtensionRAIIObject &);     // DO NOT IMPLEMENT
32    ExtensionRAIIObject(const ExtensionRAIIObject&); // DO NOT IMPLEMENT
33    Diagnostic &Diags;
34  public:
35    ExtensionRAIIObject(Diagnostic &diags) : Diags(diags) {
36      Diags.IncrementAllExtensionsSilenced();
37    }
38
39    ~ExtensionRAIIObject() {
40      Diags.DecrementAllExtensionsSilenced();
41    }
42  };
43
44  /// ColonProtectionRAIIObject - This sets the Parser::ColonIsSacred bool and
45  /// restores it when destroyed.  This says that "foo:" should not be
46  /// considered a possible typo for "foo::" for error recovery purposes.
47  class ColonProtectionRAIIObject {
48    Parser &P;
49    bool OldVal;
50  public:
51    ColonProtectionRAIIObject(Parser &p, bool Value = true)
52      : P(p), OldVal(P.ColonIsSacred) {
53      P.ColonIsSacred = Value;
54    }
55
56    /// restore - This can be used to restore the state early, before the dtor
57    /// is run.
58    void restore() {
59      P.ColonIsSacred = OldVal;
60    }
61
62    ~ColonProtectionRAIIObject() {
63      restore();
64    }
65  };
66
67  /// \brief RAII object that makes '>' behave either as an operator
68  /// or as the closing angle bracket for a template argument list.
69  class GreaterThanIsOperatorScope {
70    bool &GreaterThanIsOperator;
71    bool OldGreaterThanIsOperator;
72  public:
73    GreaterThanIsOperatorScope(bool &GTIO, bool Val)
74    : GreaterThanIsOperator(GTIO), OldGreaterThanIsOperator(GTIO) {
75      GreaterThanIsOperator = Val;
76    }
77
78    ~GreaterThanIsOperatorScope() {
79      GreaterThanIsOperator = OldGreaterThanIsOperator;
80    }
81  };
82
83} // end namespace clang
84
85#endif
86