Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/clang/include/clang/Basic/FileManager.h
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//===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// Defines the clang::FileManager interface and associated types.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
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#define LLVM_CLANG_BASIC_FILEMANAGER_H
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#include "clang/Basic/FileSystemOptions.h"
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#include "clang/Basic/LLVM.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/IntrusiveRefCntPtr.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/Allocator.h"
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#include "llvm/Support/ErrorOr.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/VirtualFileSystem.h"
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#include <ctime>
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#include <map>
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#include <memory>
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#include <string>
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namespace llvm {
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class MemoryBuffer;
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} // end namespace llvm
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namespace clang {
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class FileSystemStatCache;
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/// Cached information about one directory (either on disk or in
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/// the virtual file system).
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class DirectoryEntry {
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  friend class FileManager;
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  StringRef Name; // Name of the directory.
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public:
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4.80M
  StringRef getName() const { return Name; }
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};
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/// Cached information about one file (either on disk
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/// or in the virtual file system).
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///
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/// If the 'File' member is valid, then this FileEntry has an open file
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/// descriptor for the file.
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class FileEntry {
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  friend class FileManager;
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  StringRef Name;             // Name of the file.
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  std::string RealPathName;   // Real path to the file; could be empty.
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  off_t Size;                 // File size in bytes.
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  time_t ModTime;             // Modification time of file.
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  const DirectoryEntry *Dir;  // Directory file lives in.
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  unsigned UID;               // A unique (small) ID for the file.
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  llvm::sys::fs::UniqueID UniqueID;
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  bool IsNamedPipe;
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  bool IsValid;               // Is this \c FileEntry initialized and valid?
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  /// The open file, if it is owned by the \p FileEntry.
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  mutable std::unique_ptr<llvm::vfs::File> File;
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public:
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  FileEntry()
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      : UniqueID(0, 0), IsNamedPipe(false), IsValid(false)
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613k
  {}
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  FileEntry(const FileEntry &) = delete;
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  FileEntry &operator=(const FileEntry &) = delete;
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  StringRef getName() const { return Name; }
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2.00M
  StringRef tryGetRealPathName() const { return RealPathName; }
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615k
  bool isValid() const { return IsValid; }
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5.27M
  off_t getSize() const { return Size; }
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8.72M
  unsigned getUID() const { return UID; }
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  const llvm::sys::fs::UniqueID &getUniqueID() const { return UniqueID; }
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3.04M
  time_t getModificationTime() const { return ModTime; }
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  /// Return the directory the file lives in.
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  const DirectoryEntry *getDir() const { return Dir; }
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  bool operator<(const FileEntry &RHS) const { return UniqueID < RHS.UniqueID; }
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  /// Check whether the file is a named pipe (and thus can't be opened by
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  /// the native FileManager methods).
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  bool isNamedPipe() const { return IsNamedPipe; }
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  void closeFile() const {
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    File.reset(); // rely on destructor to close File
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  }
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  // Only for use in tests to see if deferred opens are happening, rather than
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  // relying on RealPathName being empty.
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  bool isOpenForTests() const { return File != nullptr; }
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};
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/// Implements support for file system lookup, file system caching,
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/// and directory search management.
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///
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/// This also handles more advanced properties, such as uniquing files based
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/// on "inode", so that a file with two names (e.g. symlinked) will be treated
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/// as a single file.
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///
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class FileManager : public RefCountedBase<FileManager> {
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  IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
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  FileSystemOptions FileSystemOpts;
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  /// Cache for existing real directories.
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  std::map<llvm::sys::fs::UniqueID, DirectoryEntry> UniqueRealDirs;
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  /// Cache for existing real files.
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  std::map<llvm::sys::fs::UniqueID, FileEntry> UniqueRealFiles;
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  /// The virtual directories that we have allocated.
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  ///
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  /// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
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  /// directories (foo/ and foo/bar/) here.
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  SmallVector<std::unique_ptr<DirectoryEntry>, 4> VirtualDirectoryEntries;
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  /// The virtual files that we have allocated.
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  SmallVector<std::unique_ptr<FileEntry>, 4> VirtualFileEntries;
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  /// A cache that maps paths to directory entries (either real or
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  /// virtual) we have looked up
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  ///
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  /// The actual Entries for real directories/files are
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  /// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
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  /// for virtual directories/files are owned by
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  /// VirtualDirectoryEntries/VirtualFileEntries above.
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  ///
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  llvm::StringMap<DirectoryEntry*, llvm::BumpPtrAllocator> SeenDirEntries;
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  /// A cache that maps paths to file entries (either real or
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  /// virtual) we have looked up.
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  ///
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  /// \see SeenDirEntries
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  llvm::StringMap<FileEntry*, llvm::BumpPtrAllocator> SeenFileEntries;
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  /// The canonical names of directories.
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  llvm::DenseMap<const DirectoryEntry *, llvm::StringRef> CanonicalDirNames;
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  /// Storage for canonical names that we have computed.
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  llvm::BumpPtrAllocator CanonicalNameStorage;
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  /// Each FileEntry we create is assigned a unique ID #.
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  ///
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  unsigned NextFileUID;
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  // Statistics.
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  unsigned NumDirLookups, NumFileLookups;
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  unsigned NumDirCacheMisses, NumFileCacheMisses;
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  // Caching.
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  std::unique_ptr<FileSystemStatCache> StatCache;
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  bool getStatValue(StringRef Path, llvm::vfs::Status &Status, bool isFile,
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                    std::unique_ptr<llvm::vfs::File> *F);
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  /// Add all ancestors of the given path (pointing to either a file
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  /// or a directory) as virtual directories.
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  void addAncestorsAsVirtualDirs(StringRef Path);
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  /// Fills the RealPathName in file entry.
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  void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
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public:
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  /// Construct a file manager, optionally with a custom VFS.
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  ///
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  /// \param FS if non-null, the VFS to use.  Otherwise uses
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  /// llvm::vfs::getRealFileSystem().
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  FileManager(const FileSystemOptions &FileSystemOpts,
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              IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
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  ~FileManager();
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  /// Installs the provided FileSystemStatCache object within
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  /// the FileManager.
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  ///
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  /// Ownership of this object is transferred to the FileManager.
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  ///
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  /// \param statCache the new stat cache to install. Ownership of this
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  /// object is transferred to the FileManager.
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  void setStatCache(std::unique_ptr<FileSystemStatCache> statCache);
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  /// Removes the FileSystemStatCache object from the manager.
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  void clearStatCache();
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  /// Lookup, cache, and verify the specified directory (real or
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  /// virtual).
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  ///
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  /// This returns NULL if the directory doesn't exist.
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  ///
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  /// \param CacheFailure If true and the file does not exist, we'll cache
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  /// the failure to find this file.
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  const DirectoryEntry *getDirectory(StringRef DirName,
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                                     bool CacheFailure = true);
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  /// Lookup, cache, and verify the specified file (real or
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  /// virtual).
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  ///
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  /// This returns NULL if the file doesn't exist.
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  ///
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  /// \param OpenFile if true and the file exists, it will be opened.
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  ///
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  /// \param CacheFailure If true and the file does not exist, we'll cache
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  /// the failure to find this file.
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  const FileEntry *getFile(StringRef Filename, bool OpenFile = false,
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                           bool CacheFailure = true);
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  /// Returns the current file system options
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  FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
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  const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
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  llvm::vfs::FileSystem &getVirtualFileSystem() const { return *FS; }
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  /// Retrieve a file entry for a "virtual" file that acts as
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  /// if there were a file with the given name on disk.
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  ///
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  /// The file itself is not accessed.
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  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
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                                  time_t ModificationTime);
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  /// Open the specified file as a MemoryBuffer, returning a new
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  /// MemoryBuffer if successful, otherwise returning null.
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  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
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  getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
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                   bool ShouldCloseOpenFile = true);
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  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
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  getBufferForFile(StringRef Filename, bool isVolatile = false);
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  /// Get the 'stat' information for the given \p Path.
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  ///
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  /// If the path is relative, it will be resolved against the WorkingDir of the
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  /// FileManager's FileSystemOptions.
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  ///
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  /// \returns false on success, true on error.
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  bool getNoncachedStatValue(StringRef Path, llvm::vfs::Status &Result);
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  /// Remove the real file \p Entry from the cache.
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  void invalidateCache(const FileEntry *Entry);
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  /// If path is not absolute and FileSystemOptions set the working
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  /// directory, the path is modified to be relative to the given
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  /// working directory.
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  /// \returns true if \c path changed.
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  bool FixupRelativePath(SmallVectorImpl<char> &path) const;
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  /// Makes \c Path absolute taking into account FileSystemOptions and the
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  /// working directory option.
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  /// \returns true if \c Path changed to absolute.
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  bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
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  /// Produce an array mapping from the unique IDs assigned to each
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  /// file to the corresponding FileEntry pointer.
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  void GetUniqueIDMapping(
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                    SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
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  /// Modifies the size and modification time of a previously created
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  /// FileEntry. Use with caution.
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  static void modifyFileEntry(FileEntry *File, off_t Size,
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                              time_t ModificationTime);
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  /// Retrieve the canonical name for a given directory.
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  ///
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  /// This is a very expensive operation, despite its results being cached,
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  /// and should only be used when the physical layout of the file system is
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  /// required, which is (almost) never.
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  StringRef getCanonicalName(const DirectoryEntry *Dir);
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  void PrintStats() const;
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};
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} // end namespace clang
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#endif // LLVM_CLANG_BASIC_FILEMANAGER_H