clang  17.0.0git
FileSystemStatCache.h
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1 //===- FileSystemStatCache.h - Caching for 'stat' calls ---------*- 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 /// Defines the FileSystemStatCache interface.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_BASIC_FILESYSTEMSTATCACHE_H
15 #define LLVM_CLANG_BASIC_FILESYSTEMSTATCACHE_H
16 
17 #include "clang/Basic/LLVM.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/Support/Allocator.h"
21 #include "llvm/Support/FileSystem.h"
22 #include "llvm/Support/VirtualFileSystem.h"
23 #include <cstdint>
24 #include <ctime>
25 #include <memory>
26 #include <optional>
27 #include <string>
28 #include <utility>
29 
30 namespace clang {
31 
32 /// Abstract interface for introducing a FileManager cache for 'stat'
33 /// system calls, which is used by precompiled and pretokenized headers to
34 /// improve performance.
36  virtual void anchor();
37 
38 public:
39  virtual ~FileSystemStatCache() = default;
40 
41  /// Get the 'stat' information for the specified path, using the cache
42  /// to accelerate it if possible.
43  ///
44  /// \returns \c true if the path does not exist or \c false if it exists.
45  ///
46  /// If isFile is true, then this lookup should only return success for files
47  /// (not directories). If it is false this lookup should only return
48  /// success for directories (not files). On a successful file lookup, the
49  /// implementation can optionally fill in \p F with a valid \p File object and
50  /// the client guarantees that it will close it.
51  static std::error_code
52  get(StringRef Path, llvm::vfs::Status &Status, bool isFile,
53  std::unique_ptr<llvm::vfs::File> *F,
54  FileSystemStatCache *Cache, llvm::vfs::FileSystem &FS);
55 
56 protected:
57  // FIXME: The pointer here is a non-owning/optional reference to the
58  // unique_ptr. std::optional<unique_ptr<vfs::File>&> might be nicer, but
59  // Optional needs some work to support references so this isn't possible yet.
60  virtual std::error_code getStat(StringRef Path, llvm::vfs::Status &Status,
61  bool isFile,
62  std::unique_ptr<llvm::vfs::File> *F,
63  llvm::vfs::FileSystem &FS) = 0;
64 };
65 
66 /// A stat "cache" that can be used by FileManager to keep
67 /// track of the results of stat() calls that occur throughout the
68 /// execution of the front end.
70 public:
71  /// The set of stat() calls that have been seen.
72  llvm::StringMap<llvm::vfs::Status, llvm::BumpPtrAllocator> StatCalls;
73 
74  using iterator =
75  llvm::StringMap<llvm::vfs::Status,
76  llvm::BumpPtrAllocator>::const_iterator;
77 
78  iterator begin() const { return StatCalls.begin(); }
79  iterator end() const { return StatCalls.end(); }
80 
81  std::error_code getStat(StringRef Path, llvm::vfs::Status &Status,
82  bool isFile,
83  std::unique_ptr<llvm::vfs::File> *F,
84  llvm::vfs::FileSystem &FS) override;
85 };
86 
87 } // namespace clang
88 
89 #endif // LLVM_CLANG_BASIC_FILESYSTEMSTATCACHE_H
clang::FileSystemStatCache
Abstract interface for introducing a FileManager cache for 'stat' system calls, which is used by prec...
Definition: FileSystemStatCache.h:35
clang::MemorizeStatCalls
A stat "cache" that can be used by FileManager to keep track of the results of stat() calls that occu...
Definition: FileSystemStatCache.h:69
clang::MemorizeStatCalls::begin
iterator begin() const
Definition: FileSystemStatCache.h:78
clang::FileSystemStatCache::getStat
virtual std::error_code getStat(StringRef Path, llvm::vfs::Status &Status, bool isFile, std::unique_ptr< llvm::vfs::File > *F, llvm::vfs::FileSystem &FS)=0
clang::FileSystemStatCache::get
static std::error_code get(StringRef Path, llvm::vfs::Status &Status, bool isFile, std::unique_ptr< llvm::vfs::File > *F, FileSystemStatCache *Cache, llvm::vfs::FileSystem &FS)
Get the 'stat' information for the specified path, using the cache to accelerate it if possible.
Definition: FileSystemStatCache.cpp:34
clang::MemorizeStatCalls::end
iterator end() const
Definition: FileSystemStatCache.h:79
Cache
TypePropertyCache< Private > Cache
Definition: Type.cpp:3973
clang::FileSystemStatCache::~FileSystemStatCache
virtual ~FileSystemStatCache()=default
LLVM.h
clang::MemorizeStatCalls::StatCalls
llvm::StringMap< llvm::vfs::Status, llvm::BumpPtrAllocator > StatCalls
The set of stat() calls that have been seen.
Definition: FileSystemStatCache.h:72
clang::MemorizeStatCalls::iterator
llvm::StringMap< llvm::vfs::Status, llvm::BumpPtrAllocator >::const_iterator iterator
Definition: FileSystemStatCache.h:76
clang
Definition: CalledOnceCheck.h:17
clang::MemorizeStatCalls::getStat
std::error_code getStat(StringRef Path, llvm::vfs::Status &Status, bool isFile, std::unique_ptr< llvm::vfs::File > *F, llvm::vfs::FileSystem &FS) override
Definition: FileSystemStatCache.cpp:102