Coverage Report

Created: 2021-08-24 07:12

/Users/buildslave/jenkins/workspace/coverage/llvm-project/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/DirectoryEntry.h"
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#include "clang/Basic/FileEntry.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/PointerUnion.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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/// 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 set of files that bypass the maps and uniquing.  They can have
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  /// conflicting filenames.
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  SmallVector<std::unique_ptr<FileEntry>, 0> BypassFileEntries;
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  /// A cache that maps paths to directory entries (either real or
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  /// virtual) we have looked up, or an error that occurred when we looked up
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  /// the directory.
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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<llvm::ErrorOr<DirectoryEntry &>, llvm::BumpPtrAllocator>
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  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, or an error that occurred when we looked up
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  /// the file.
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  ///
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  /// \see SeenDirEntries
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  llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>, llvm::BumpPtrAllocator>
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      SeenFileEntries;
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  /// A mirror of SeenFileEntries to give fake answers for getBypassFile().
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  ///
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  /// Don't bother hooking up a BumpPtrAllocator. This should be rarely used,
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  /// and only on error paths.
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  std::unique_ptr<llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>>>
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      SeenBypassFileEntries;
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  /// The file entry for stdin, if it has been accessed through the FileManager.
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  Optional<FileEntryRef> STDIN;
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  /// The canonical names of files and directories .
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  llvm::DenseMap<const void *, llvm::StringRef> CanonicalNames;
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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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  // Caching.
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  std::unique_ptr<FileSystemStatCache> StatCache;
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  std::error_code getStatValue(StringRef Path, llvm::vfs::Status &Status,
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                               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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  /// Returns the number of unique real file entries cached by the file manager.
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  size_t getNumUniqueRealFiles() const { return UniqueRealFiles.size(); }
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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 a \c std::error_code if there was an error reading the
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  /// directory. On success, returns the reference to the directory entry
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  /// together with the exact path that was used to access a file by a
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  /// particular call to getDirectoryRef.
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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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  llvm::Expected<DirectoryEntryRef> getDirectoryRef(StringRef DirName,
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                                                    bool CacheFailure = true);
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  /// Get a \c DirectoryEntryRef if it exists, without doing anything on error.
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  llvm::Optional<DirectoryEntryRef>
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  getOptionalDirectoryRef(StringRef DirName, bool CacheFailure = true) {
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    return llvm::expectedToOptional(getDirectoryRef(DirName, CacheFailure));
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  }
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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 function is deprecated and will be removed at some point in the
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  /// future, new clients should use
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  ///  \c getDirectoryRef.
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  ///
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  /// This returns a \c std::error_code if there was an error reading the
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  /// directory. If there is no error, the DirectoryEntry is guaranteed to be
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  /// non-NULL.
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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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  llvm::ErrorOr<const DirectoryEntry *>
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  getDirectory(StringRef DirName, 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 function is deprecated and will be removed at some point in the
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  /// future, new clients should use
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  ///  \c getFileRef.
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  ///
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  /// This returns a \c std::error_code if there was an error loading the file.
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  /// If there is no error, the FileEntry is guaranteed to be non-NULL.
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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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  llvm::ErrorOr<const FileEntry *>
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  getFile(StringRef Filename, bool OpenFile = false, bool CacheFailure = true);
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  /// Lookup, cache, and verify the specified file (real or virtual). Return the
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  /// reference to the file entry together with the exact path that was used to
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  /// access a file by a particular call to getFileRef. If the underlying VFS is
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  /// a redirecting VFS that uses external file names, the returned FileEntryRef
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  /// will use the external name instead of the filename that was passed to this
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  /// method.
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  ///
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  /// This returns a \c std::error_code if there was an error loading the file,
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  /// or a \c FileEntryRef otherwise.
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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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  llvm::Expected<FileEntryRef> getFileRef(StringRef Filename,
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                                          bool OpenFile = false,
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                                          bool CacheFailure = true);
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  /// Get the FileEntryRef for stdin, returning an error if stdin cannot be
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  /// read.
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  ///
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  /// This reads and caches stdin before returning. Subsequent calls return the
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  /// same file entry, and a reference to the cached input is returned by calls
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  /// to getBufferForFile.
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  llvm::Expected<FileEntryRef> getSTDIN();
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  /// Get a FileEntryRef if it exists, without doing anything on error.
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  llvm::Optional<FileEntryRef> getOptionalFileRef(StringRef Filename,
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                                                  bool OpenFile = false,
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                                                  bool CacheFailure = true) {
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    return llvm::expectedToOptional(
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        getFileRef(Filename, OpenFile, CacheFailure));
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  }
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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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  void setVirtualFileSystem(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
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    this->FS = std::move(FS);
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  }
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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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  FileEntryRef getVirtualFileRef(StringRef Filename, off_t Size,
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                                 time_t ModificationTime);
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  const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
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                                  time_t ModificationTime);
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  /// Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual
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  /// file entry, to access the real file.  The returned FileEntry will have
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  /// the same filename as FE but a different identity and its own stat.
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  ///
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  /// This should be used only for rare error recovery paths because it
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  /// bypasses all mapping and uniquing, blindly creating a new FileEntry.
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  /// There is no attempt to deduplicate these; if you bypass the same file
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  /// twice, you get two new file entries.
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  llvm::Optional<FileEntryRef> getBypassFile(FileEntryRef VFE);
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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 RequiresNullTerminator = 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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                   bool RequiresNullTerminator = true) {
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    return getBufferForFileImpl(Filename, /*FileSize=*/-1, isVolatile,
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                                RequiresNullTerminator);
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  }
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private:
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  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
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  getBufferForFileImpl(StringRef Filename, int64_t FileSize, bool isVolatile,
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                       bool RequiresNullTerminator);
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public:
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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 a \c std::error_code describing an error, if there was one
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  std::error_code getNoncachedStatValue(StringRef Path,
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                                        llvm::vfs::Status &Result);
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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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  /// 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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  /// Retrieve the canonical name for a given file.
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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 FileEntry *File);
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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