//===--- FileManager.h - File System Probing and Caching --------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Defines the clang::FileManager interface and associated types.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_BASIC_FILEMANAGER_H
#define LLVM_CLANG_BASIC_FILEMANAGER_H
#include "clang/Basic/DirectoryEntry.h"
#include "clang/Basic/FileEntry.h"
#include "clang/Basic/FileSystemOptions.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/VirtualFileSystem.h"
#include <ctime>
#include <map>
#include <memory>
#include <string>
namespace llvm {
class MemoryBuffer;
} // end namespace llvm
namespace clang {
class FileSystemStatCache;
/// Implements support for file system lookup, file system caching,
/// and directory search management.
///
/// This also handles more advanced properties, such as uniquing files based
/// on "inode", so that a file with two names (e.g. symlinked) will be treated
/// as a single file.
///
class FileManager : public RefCountedBase<FileManager> {
IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS;
FileSystemOptions FileSystemOpts;
llvm::SpecificBumpPtrAllocator<FileEntry> FilesAlloc;
llvm::SpecificBumpPtrAllocator<DirectoryEntry> DirsAlloc;
/// Cache for existing real directories.
llvm::DenseMap<llvm::sys::fs::UniqueID, DirectoryEntry *> UniqueRealDirs;
/// Cache for existing real files.
llvm::DenseMap<llvm::sys::fs::UniqueID, FileEntry *> UniqueRealFiles;
/// The virtual directories that we have allocated.
///
/// For each virtual file (e.g. foo/bar/baz.cpp), we add all of its parent
/// directories (foo/ and foo/bar/) here.
SmallVector<DirectoryEntry *, 4> VirtualDirectoryEntries;
/// The virtual files that we have allocated.
SmallVector<FileEntry *, 4> VirtualFileEntries;
/// A set of files that bypass the maps and uniquing. They can have
/// conflicting filenames.
SmallVector<FileEntry *, 0> BypassFileEntries;
/// A cache that maps paths to directory entries (either real or
/// virtual) we have looked up, or an error that occurred when we looked up
/// the directory.
///
/// The actual Entries for real directories/files are
/// owned by UniqueRealDirs/UniqueRealFiles above, while the Entries
/// for virtual directories/files are owned by
/// VirtualDirectoryEntries/VirtualFileEntries above.
///
llvm::StringMap<llvm::ErrorOr<DirectoryEntry &>, llvm::BumpPtrAllocator>
SeenDirEntries;
/// A cache that maps paths to file entries (either real or
/// virtual) we have looked up, or an error that occurred when we looked up
/// the file.
///
/// \see SeenDirEntries
llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>, llvm::BumpPtrAllocator>
SeenFileEntries;
/// A mirror of SeenFileEntries to give fake answers for getBypassFile().
///
/// Don't bother hooking up a BumpPtrAllocator. This should be rarely used,
/// and only on error paths.
std::unique_ptr<llvm::StringMap<llvm::ErrorOr<FileEntryRef::MapValue>>>
SeenBypassFileEntries;
/// The file entry for stdin, if it has been accessed through the FileManager.
OptionalFileEntryRef STDIN;
/// The canonical names of files and directories .
llvm::DenseMap<const void *, llvm::StringRef> CanonicalNames;
/// Storage for canonical names that we have computed.
llvm::BumpPtrAllocator CanonicalNameStorage;
/// Each FileEntry we create is assigned a unique ID #.
///
unsigned NextFileUID;
// Caching.
std::unique_ptr<FileSystemStatCache> StatCache;
std::error_code getStatValue(StringRef Path, llvm::vfs::Status &Status,
bool isFile,
std::unique_ptr<llvm::vfs::File> *F);
/// Add all ancestors of the given path (pointing to either a file
/// or a directory) as virtual directories.
void addAncestorsAsVirtualDirs(StringRef Path);
/// Fills the RealPathName in file entry.
void fillRealPathName(FileEntry *UFE, llvm::StringRef FileName);
public:
/// Construct a file manager, optionally with a custom VFS.
///
/// \param FS if non-null, the VFS to use. Otherwise uses
/// llvm::vfs::getRealFileSystem().
FileManager(const FileSystemOptions &FileSystemOpts,
IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = nullptr);
~FileManager();
/// Installs the provided FileSystemStatCache object within
/// the FileManager.
///
/// Ownership of this object is transferred to the FileManager.
///
/// \param statCache the new stat cache to install. Ownership of this
/// object is transferred to the FileManager.
void setStatCache(std::unique_ptr<FileSystemStatCache> statCache);
/// Removes the FileSystemStatCache object from the manager.
void clearStatCache();
/// Returns the number of unique real file entries cached by the file manager.
size_t getNumUniqueRealFiles() const { return UniqueRealFiles.size(); }
/// Lookup, cache, and verify the specified directory (real or
/// virtual).
///
/// This returns a \c std::error_code if there was an error reading the
/// directory. On success, returns the reference to the directory entry
/// together with the exact path that was used to access a file by a
/// particular call to getDirectoryRef.
///
/// \param CacheFailure If true and the file does not exist, we'll cache
/// the failure to find this file.
llvm::Expected<DirectoryEntryRef> getDirectoryRef(StringRef DirName,
bool CacheFailure = true);
/// Get a \c DirectoryEntryRef if it exists, without doing anything on error.
OptionalDirectoryEntryRef getOptionalDirectoryRef(StringRef DirName,
bool CacheFailure = true) {
return llvm::expectedToOptional(getDirectoryRef(DirName, CacheFailure));
}
/// Lookup, cache, and verify the specified directory (real or
/// virtual).
///
/// This function is deprecated and will be removed at some point in the
/// future, new clients should use
/// \c getDirectoryRef.
///
/// This returns a \c std::error_code if there was an error reading the
/// directory. If there is no error, the DirectoryEntry is guaranteed to be
/// non-NULL.
///
/// \param CacheFailure If true and the file does not exist, we'll cache
/// the failure to find this file.
llvm::ErrorOr<const DirectoryEntry *>
getDirectory(StringRef DirName, bool CacheFailure = true);
/// Lookup, cache, and verify the specified file (real or
/// virtual).
///
/// This function is deprecated and will be removed at some point in the
/// future, new clients should use
/// \c getFileRef.
///
/// This returns a \c std::error_code if there was an error loading the file.
/// If there is no error, the FileEntry is guaranteed to be non-NULL.
///
/// \param OpenFile if true and the file exists, it will be opened.
///
/// \param CacheFailure If true and the file does not exist, we'll cache
/// the failure to find this file.
llvm::ErrorOr<const FileEntry *>
getFile(StringRef Filename, bool OpenFile = false, bool CacheFailure = true);
/// Lookup, cache, and verify the specified file (real or virtual). Return the
/// reference to the file entry together with the exact path that was used to
/// access a file by a particular call to getFileRef. If the underlying VFS is
/// a redirecting VFS that uses external file names, the returned FileEntryRef
/// will use the external name instead of the filename that was passed to this
/// method.
///
/// This returns a \c std::error_code if there was an error loading the file,
/// or a \c FileEntryRef otherwise.
///
/// \param OpenFile if true and the file exists, it will be opened.
///
/// \param CacheFailure If true and the file does not exist, we'll cache
/// the failure to find this file.
llvm::Expected<FileEntryRef> getFileRef(StringRef Filename,
bool OpenFile = false,
bool CacheFailure = true);
/// Get the FileEntryRef for stdin, returning an error if stdin cannot be
/// read.
///
/// This reads and caches stdin before returning. Subsequent calls return the
/// same file entry, and a reference to the cached input is returned by calls
/// to getBufferForFile.
llvm::Expected<FileEntryRef> getSTDIN();
/// Get a FileEntryRef if it exists, without doing anything on error.
OptionalFileEntryRef getOptionalFileRef(StringRef Filename,
bool OpenFile = false,
bool CacheFailure = true) {
return llvm::expectedToOptional(
getFileRef(Filename, OpenFile, CacheFailure));
}
/// Returns the current file system options
FileSystemOptions &getFileSystemOpts() { return FileSystemOpts; }
const FileSystemOptions &getFileSystemOpts() const { return FileSystemOpts; }
llvm::vfs::FileSystem &getVirtualFileSystem() const { return *FS; }
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>
getVirtualFileSystemPtr() const {
return FS;
}
void setVirtualFileSystem(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
this->FS = std::move(FS);
}
/// Retrieve a file entry for a "virtual" file that acts as
/// if there were a file with the given name on disk.
///
/// The file itself is not accessed.
FileEntryRef getVirtualFileRef(StringRef Filename, off_t Size,
time_t ModificationTime);
const FileEntry *getVirtualFile(StringRef Filename, off_t Size,
time_t ModificationTime);
/// Retrieve a FileEntry that bypasses VFE, which is expected to be a virtual
/// file entry, to access the real file. The returned FileEntry will have
/// the same filename as FE but a different identity and its own stat.
///
/// This should be used only for rare error recovery paths because it
/// bypasses all mapping and uniquing, blindly creating a new FileEntry.
/// There is no attempt to deduplicate these; if you bypass the same file
/// twice, you get two new file entries.
OptionalFileEntryRef getBypassFile(FileEntryRef VFE);
/// Open the specified file as a MemoryBuffer, returning a new
/// MemoryBuffer if successful, otherwise returning null.
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBufferForFile(const FileEntry *Entry, bool isVolatile = false,
bool RequiresNullTerminator = true);
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBufferForFile(StringRef Filename, bool isVolatile = false,
bool RequiresNullTerminator = true) {
return getBufferForFileImpl(Filename, /*FileSize=*/-1, isVolatile,
RequiresNullTerminator);
}
private:
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBufferForFileImpl(StringRef Filename, int64_t FileSize, bool isVolatile,
bool RequiresNullTerminator);
public:
/// Get the 'stat' information for the given \p Path.
///
/// If the path is relative, it will be resolved against the WorkingDir of the
/// FileManager's FileSystemOptions.
///
/// \returns a \c std::error_code describing an error, if there was one
std::error_code getNoncachedStatValue(StringRef Path,
llvm::vfs::Status &Result);
/// If path is not absolute and FileSystemOptions set the working
/// directory, the path is modified to be relative to the given
/// working directory.
/// \returns true if \c path changed.
bool FixupRelativePath(SmallVectorImpl<char> &path) const;
/// Makes \c Path absolute taking into account FileSystemOptions and the
/// working directory option.
/// \returns true if \c Path changed to absolute.
bool makeAbsolutePath(SmallVectorImpl<char> &Path) const;
/// Produce an array mapping from the unique IDs assigned to each
/// file to the corresponding FileEntry pointer.
void GetUniqueIDMapping(
SmallVectorImpl<const FileEntry *> &UIDToFiles) const;
/// Retrieve the canonical name for a given directory.
///
/// This is a very expensive operation, despite its results being cached,
/// and should only be used when the physical layout of the file system is
/// required, which is (almost) never.
StringRef getCanonicalName(const DirectoryEntry *Dir);
/// Retrieve the canonical name for a given file.
///
/// This is a very expensive operation, despite its results being cached,
/// and should only be used when the physical layout of the file system is
/// required, which is (almost) never.
StringRef getCanonicalName(const FileEntry *File);
void PrintStats() const;
};
} // end namespace clang
#endif // LLVM_CLANG_BASIC_FILEMANAGER_H