278 lines
9.8 KiB
C++
278 lines
9.8 KiB
C++
//===- VirtualFileSystem.h - Virtual File System Layer ----------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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/// \file
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/// \brief Defines the virtual file system interface vfs::FileSystem.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H
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#define LLVM_CLANG_BASIC_VIRTUALFILESYSTEM_H
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#include "clang/Basic/LLVM.h"
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#include "llvm/ADT/IntrusiveRefCntPtr.h"
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#include "llvm/ADT/Optional.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/SourceMgr.h"
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#include "llvm/Support/raw_ostream.h"
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namespace llvm {
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class MemoryBuffer;
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}
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namespace clang {
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namespace vfs {
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/// \brief The result of a \p status operation.
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class Status {
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std::string Name;
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llvm::sys::fs::UniqueID UID;
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llvm::sys::TimeValue MTime;
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uint32_t User;
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uint32_t Group;
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uint64_t Size;
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llvm::sys::fs::file_type Type;
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llvm::sys::fs::perms Perms;
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public:
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bool IsVFSMapped; // FIXME: remove when files support multiple names
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public:
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Status() : Type(llvm::sys::fs::file_type::status_error) {}
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Status(const llvm::sys::fs::file_status &Status);
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Status(StringRef Name, StringRef RealName, llvm::sys::fs::UniqueID UID,
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llvm::sys::TimeValue MTime, uint32_t User, uint32_t Group,
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uint64_t Size, llvm::sys::fs::file_type Type,
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llvm::sys::fs::perms Perms);
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/// \brief Returns the name that should be used for this file or directory.
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StringRef getName() const { return Name; }
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void setName(StringRef N) { Name = N; }
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/// @name Status interface from llvm::sys::fs
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/// @{
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llvm::sys::fs::file_type getType() const { return Type; }
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llvm::sys::fs::perms getPermissions() const { return Perms; }
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llvm::sys::TimeValue getLastModificationTime() const { return MTime; }
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llvm::sys::fs::UniqueID getUniqueID() const { return UID; }
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uint32_t getUser() const { return User; }
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uint32_t getGroup() const { return Group; }
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uint64_t getSize() const { return Size; }
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void setType(llvm::sys::fs::file_type v) { Type = v; }
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void setPermissions(llvm::sys::fs::perms p) { Perms = p; }
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/// @}
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/// @name Status queries
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/// These are static queries in llvm::sys::fs.
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/// @{
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bool equivalent(const Status &Other) const;
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bool isDirectory() const;
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bool isRegularFile() const;
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bool isOther() const;
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bool isSymlink() const;
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bool isStatusKnown() const;
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bool exists() const;
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/// @}
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};
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/// \brief Represents an open file.
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class File {
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public:
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/// \brief Destroy the file after closing it (if open).
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/// Sub-classes should generally call close() inside their destructors. We
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/// cannot do that from the base class, since close is virtual.
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virtual ~File();
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/// \brief Get the status of the file.
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virtual llvm::ErrorOr<Status> status() = 0;
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/// \brief Get the contents of the file as a \p MemoryBuffer.
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virtual llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
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getBuffer(const Twine &Name, int64_t FileSize = -1,
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bool RequiresNullTerminator = true, bool IsVolatile = false) = 0;
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/// \brief Closes the file.
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virtual std::error_code close() = 0;
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/// \brief Sets the name to use for this file.
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virtual void setName(StringRef Name) = 0;
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};
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namespace detail {
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/// \brief An interface for virtual file systems to provide an iterator over the
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/// (non-recursive) contents of a directory.
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struct DirIterImpl {
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virtual ~DirIterImpl();
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/// \brief Sets \c CurrentEntry to the next entry in the directory on success,
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/// or returns a system-defined \c error_code.
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virtual std::error_code increment() = 0;
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Status CurrentEntry;
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};
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} // end namespace detail
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/// \brief An input iterator over the entries in a virtual path, similar to
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/// llvm::sys::fs::directory_iterator.
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class directory_iterator {
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std::shared_ptr<detail::DirIterImpl> Impl; // Input iterator semantics on copy
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public:
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directory_iterator(std::shared_ptr<detail::DirIterImpl> I) : Impl(I) {
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assert(Impl.get() != nullptr && "requires non-null implementation");
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if (!Impl->CurrentEntry.isStatusKnown())
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Impl.reset(); // Normalize the end iterator to Impl == nullptr.
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}
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/// \brief Construct an 'end' iterator.
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directory_iterator() { }
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/// \brief Equivalent to operator++, with an error code.
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directory_iterator &increment(std::error_code &EC) {
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assert(Impl && "attempting to increment past end");
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EC = Impl->increment();
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if (EC || !Impl->CurrentEntry.isStatusKnown())
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Impl.reset(); // Normalize the end iterator to Impl == nullptr.
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return *this;
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}
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const Status &operator*() const { return Impl->CurrentEntry; }
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const Status *operator->() const { return &Impl->CurrentEntry; }
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bool operator==(const directory_iterator &RHS) const {
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if (Impl && RHS.Impl)
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return Impl->CurrentEntry.equivalent(RHS.Impl->CurrentEntry);
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return !Impl && !RHS.Impl;
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}
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bool operator!=(const directory_iterator &RHS) const {
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return !(*this == RHS);
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}
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};
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class FileSystem;
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/// \brief An input iterator over the recursive contents of a virtual path,
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/// similar to llvm::sys::fs::recursive_directory_iterator.
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class recursive_directory_iterator {
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typedef std::stack<directory_iterator, std::vector<directory_iterator>>
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IterState;
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FileSystem *FS;
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std::shared_ptr<IterState> State; // Input iterator semantics on copy.
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public:
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recursive_directory_iterator(FileSystem &FS, const Twine &Path,
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std::error_code &EC);
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/// \brief Construct an 'end' iterator.
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recursive_directory_iterator() { }
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/// \brief Equivalent to operator++, with an error code.
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recursive_directory_iterator &increment(std::error_code &EC);
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const Status &operator*() const { return *State->top(); }
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const Status *operator->() const { return &*State->top(); }
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bool operator==(const recursive_directory_iterator &Other) const {
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return State == Other.State; // identity
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}
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bool operator!=(const recursive_directory_iterator &RHS) const {
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return !(*this == RHS);
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}
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};
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/// \brief The virtual file system interface.
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class FileSystem : public llvm::ThreadSafeRefCountedBase<FileSystem> {
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public:
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virtual ~FileSystem();
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/// \brief Get the status of the entry at \p Path, if one exists.
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virtual llvm::ErrorOr<Status> status(const Twine &Path) = 0;
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/// \brief Get a \p File object for the file at \p Path, if one exists.
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virtual llvm::ErrorOr<std::unique_ptr<File>>
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openFileForRead(const Twine &Path) = 0;
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/// This is a convenience method that opens a file, gets its content and then
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/// closes the file.
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llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
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getBufferForFile(const Twine &Name, int64_t FileSize = -1,
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bool RequiresNullTerminator = true, bool IsVolatile = false);
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/// \brief Get a directory_iterator for \p Dir.
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/// \note The 'end' iterator is directory_iterator().
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virtual directory_iterator dir_begin(const Twine &Dir,
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std::error_code &EC) = 0;
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};
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/// \brief Gets an \p vfs::FileSystem for the 'real' file system, as seen by
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/// the operating system.
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IntrusiveRefCntPtr<FileSystem> getRealFileSystem();
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/// \brief A file system that allows overlaying one \p AbstractFileSystem on top
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/// of another.
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///
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/// Consists of a stack of >=1 \p FileSystem objects, which are treated as being
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/// one merged file system. When there is a directory that exists in more than
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/// one file system, the \p OverlayFileSystem contains a directory containing
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/// the union of their contents. The attributes (permissions, etc.) of the
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/// top-most (most recently added) directory are used. When there is a file
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/// that exists in more than one file system, the file in the top-most file
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/// system overrides the other(s).
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class OverlayFileSystem : public FileSystem {
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typedef SmallVector<IntrusiveRefCntPtr<FileSystem>, 1> FileSystemList;
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/// \brief The stack of file systems, implemented as a list in order of
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/// their addition.
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FileSystemList FSList;
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public:
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OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> Base);
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/// \brief Pushes a file system on top of the stack.
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void pushOverlay(IntrusiveRefCntPtr<FileSystem> FS);
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llvm::ErrorOr<Status> status(const Twine &Path) override;
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llvm::ErrorOr<std::unique_ptr<File>>
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openFileForRead(const Twine &Path) override;
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directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
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typedef FileSystemList::reverse_iterator iterator;
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/// \brief Get an iterator pointing to the most recently added file system.
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iterator overlays_begin() { return FSList.rbegin(); }
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/// \brief Get an iterator pointing one-past the least recently added file
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/// system.
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iterator overlays_end() { return FSList.rend(); }
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};
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/// \brief Get a globally unique ID for a virtual file or directory.
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llvm::sys::fs::UniqueID getNextVirtualUniqueID();
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/// \brief Gets a \p FileSystem for a virtual file system described in YAML
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/// format.
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IntrusiveRefCntPtr<FileSystem>
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getVFSFromYAML(std::unique_ptr<llvm::MemoryBuffer> Buffer,
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llvm::SourceMgr::DiagHandlerTy DiagHandler,
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void *DiagContext = nullptr,
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IntrusiveRefCntPtr<FileSystem> ExternalFS = getRealFileSystem());
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struct YAMLVFSEntry {
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template <typename T1, typename T2> YAMLVFSEntry(T1 &&VPath, T2 &&RPath)
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: VPath(std::forward<T1>(VPath)), RPath(std::forward<T2>(RPath)) {}
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std::string VPath;
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std::string RPath;
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};
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class YAMLVFSWriter {
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std::vector<YAMLVFSEntry> Mappings;
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Optional<bool> IsCaseSensitive;
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public:
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YAMLVFSWriter() {}
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void addFileMapping(StringRef VirtualPath, StringRef RealPath);
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void setCaseSensitivity(bool CaseSensitive) {
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IsCaseSensitive = CaseSensitive;
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}
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void write(llvm::raw_ostream &OS);
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};
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} // end namespace vfs
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} // end namespace clang
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#endif
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