/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Basic/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. |
34 | | class FileSystemStatCache { |
35 | | virtual void anchor(); |
36 | | |
37 | | public: |
38 | 14 | 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. |
68 | | class MemorizeStatCalls : public FileSystemStatCache { |
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 | 0 | iterator begin() const { return StatCalls.begin(); } |
78 | 0 | 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 |