clang  14.0.0git
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 <string>
27 #include <utility>
28 
29 namespace clang {
30 
31 /// Abstract interface for introducing a FileManager cache for 'stat'
32 /// system calls, which is used by precompiled and pretokenized headers to
33 /// improve performance.
35  virtual void anchor();
36 
37 public:
38  virtual ~FileSystemStatCache() = default;
39 
40  /// Get the 'stat' information for the specified path, using the cache
41  /// to accelerate it if possible.
42  ///
43  /// \returns \c true if the path does not exist or \c false if it exists.
44  ///
45  /// If isFile is true, then this lookup should only return success for files
46  /// (not directories). If it is false this lookup should only return
47  /// success for directories (not files). On a successful file lookup, the
48  /// implementation can optionally fill in \p F with a valid \p File object and
49  /// the client guarantees that it will close it.
50  static std::error_code
51  get(StringRef Path, llvm::vfs::Status &Status, bool isFile,
52  std::unique_ptr<llvm::vfs::File> *F,
53  FileSystemStatCache *Cache, llvm::vfs::FileSystem &FS);
54 
55 protected:
56  // FIXME: The pointer here is a non-owning/optional reference to the
57  // unique_ptr. Optional<unique_ptr<vfs::File>&> might be nicer, but
58  // Optional needs some work to support references so this isn't possible yet.
59  virtual std::error_code getStat(StringRef Path, llvm::vfs::Status &Status,
60  bool isFile,
61  std::unique_ptr<llvm::vfs::File> *F,
62  llvm::vfs::FileSystem &FS) = 0;
63 };
64 
65 /// A stat "cache" that can be used by FileManager to keep
66 /// track of the results of stat() calls that occur throughout the
67 /// execution of the front end.
69 public:
70  /// The set of stat() calls that have been seen.
71  llvm::StringMap<llvm::vfs::Status, llvm::BumpPtrAllocator> StatCalls;
72 
73  using iterator =
74  llvm::StringMap<llvm::vfs::Status,
75  llvm::BumpPtrAllocator>::const_iterator;
76 
77  iterator begin() const { return StatCalls.begin(); }
78  iterator end() const { return StatCalls.end(); }
79 
80  std::error_code getStat(StringRef Path, llvm::vfs::Status &Status,
81  bool isFile,
82  std::unique_ptr<llvm::vfs::File> *F,
83  llvm::vfs::FileSystem &FS) override;
84 };
85 
86 } // namespace clang
87 
88 #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:34
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:68
clang::MemorizeStatCalls::begin
iterator begin() const
Definition: FileSystemStatCache.h:77
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:78
Cache
TypePropertyCache< Private > Cache
Definition: Type.cpp:3822
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:71
clang::MemorizeStatCalls::iterator
llvm::StringMap< llvm::vfs::Status, llvm::BumpPtrAllocator >::const_iterator iterator
Definition: FileSystemStatCache.h:75
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