FileCollector.h revision 360784 
1//===-- FileCollector.h -----------------------------------------*- 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#ifndef LLVM_SUPPORT_FILE_COLLECTOR_H
10#define LLVM_SUPPORT_FILE_COLLECTOR_H
11
12#include "llvm/ADT/SmallVector.h"
13#include "llvm/ADT/StringMap.h"
14#include "llvm/ADT/StringSet.h"
15#include "llvm/ADT/Twine.h"
16#include "llvm/Support/VirtualFileSystem.h"
17
18#include <mutex>
19
20namespace llvm {
21
22/// Collects files into a directory and generates a mapping that can be used by
23/// the VFS.
24class FileCollector {
25public:
26  FileCollector(std::string Root, std::string OverlayRoot);
27
28  void addFile(const Twine &file);
29
30  /// Write the yaml mapping (for the VFS) to the given file.
31  std::error_code writeMapping(StringRef mapping_file);
32
33  /// Copy the files into the root directory.
34  ///
35  /// When StopOnError is true (the default) we abort as soon as one file
36  /// cannot be copied. This is relatively common, for example when a file was
37  /// removed after it was added to the mapping.
38  std::error_code copyFiles(bool StopOnError = true);
39
40  /// Create a VFS that collects all the paths that might be looked at by the
41  /// file system accesses.
42  static IntrusiveRefCntPtr<vfs::FileSystem>
43  createCollectorVFS(IntrusiveRefCntPtr<vfs::FileSystem> BaseFS,
44                     std::shared_ptr<FileCollector> Collector);
45
46private:
47  void addFileImpl(StringRef SrcPath);
48
49  bool markAsSeen(StringRef Path) {
50    if (Path.empty())
51      return false;
52    return Seen.insert(Path).second;
53  }
54
55  bool getRealPath(StringRef SrcPath, SmallVectorImpl<char> &Result);
56
57  void addFileToMapping(StringRef VirtualPath, StringRef RealPath) {
58    VFSWriter.addFileMapping(VirtualPath, RealPath);
59  }
60
61protected:
62  /// Synchronizes adding files.
63  std::mutex Mutex;
64
65  /// The root directory where files are copied.
66  std::string Root;
67
68  /// The root directory where the VFS overlay lives.
69  std::string OverlayRoot;
70
71  /// Tracks already seen files so they can be skipped.
72  StringSet<> Seen;
73
74  /// The yaml mapping writer.
75  vfs::YAMLVFSWriter VFSWriter;
76
77  /// Caches RealPath calls when resolving symlinks.
78  StringMap<std::string> SymlinkMap;
79};
80
81} // end namespace llvm
82
83#endif // LLVM_SUPPORT_FILE_COLLECTOR_H
84