llvm/clang/include/clang/Tooling/DependencyScanning/DependencyScanningFilesystem.h

//===- DependencyScanningFilesystem.h - clang-scan-deps fs ===---*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_TOOLING_DEPENDENCYSCANNING_DEPENDENCYSCANNINGFILESYSTEM_H
#define LLVM_CLANG_TOOLING_DEPENDENCYSCANNING_DEPENDENCYSCANNINGFILESYSTEM_H

#include "clang/Basic/LLVM.h"
#include "clang/Lex/DependencyDirectivesScanner.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/VirtualFileSystem.h"
#include <mutex>
#include <optional>

namespace clang {
namespace tooling {
namespace dependencies {

DependencyDirectivesTy;

/// Contents and directive tokens of a cached file entry. Single instance can
/// be shared between multiple entries.
struct CachedFileContents { … };

/// An in-memory representation of a file system entity that is of interest to
/// the dependency scanning filesystem.
///
/// It represents one of the following:
/// - opened file with contents and a stat value,
/// - opened file with contents, directive tokens and a stat value,
/// - directory entry with its stat value,
/// - filesystem error.
///
/// Single instance of this class can be shared across different filenames (e.g.
/// a regular file and a symlink). For this reason the status filename is empty
/// and is only materialized by \c EntryRef that knows the requested filename.
class CachedFileSystemEntry { … };

CachedRealPath;

/// This class is a shared cache, that caches the 'stat' and 'open' calls to the
/// underlying real file system, and the scanned preprocessor directives of
/// files.
///
/// It is sharded based on the hash of the key to reduce the lock contention for
/// the worker threads.
class DependencyScanningFilesystemSharedCache { … };

/// This class is a local cache, that caches the 'stat' and 'open' calls to the
/// underlying real file system.
class DependencyScanningFilesystemLocalCache { … };

/// Reference to a CachedFileSystemEntry.
/// If the underlying entry is an opened file, this wrapper returns the file
/// contents and the scanned preprocessor directives.
class EntryRef { … };

/// A virtual file system optimized for the dependency discovery.
///
/// It is primarily designed to work with source files whose contents was
/// preprocessed to remove any tokens that are unlikely to affect the dependency
/// computation.
///
/// This is not a thread safe VFS. A single instance is meant to be used only in
/// one thread. Multiple instances are allowed to service multiple threads
/// running in parallel.
class DependencyScanningWorkerFilesystem
    : public llvm::RTTIExtends<DependencyScanningWorkerFilesystem,
                               llvm::vfs::ProxyFileSystem> { … };

} // end namespace dependencies
} // end namespace tooling
} // end namespace clang

#endif // LLVM_CLANG_TOOLING_DEPENDENCYSCANNING_DEPENDENCYSCANNINGFILESYSTEM_H