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llvm-project/clang/lib/Basic/VirtualFileSystem.cpp

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//===- VirtualFileSystem.cpp - Virtual File System Layer --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// This file implements the VirtualFileSystem interface.
//===----------------------------------------------------------------------===//
#include "clang/Basic/VirtualFileSystem.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Atomic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/YAMLParser.h"
using namespace clang;
using namespace clang::vfs;
using namespace llvm;
using llvm::sys::fs::file_status;
using llvm::sys::fs::file_type;
using llvm::sys::fs::perms;
using llvm::sys::fs::UniqueID;
Status::Status(const file_status &Status)
: UID(Status.getUniqueID()), MTime(Status.getLastModificationTime()),
User(Status.getUser()), Group(Status.getGroup()), Size(Status.getSize()),
Type(Status.type()), Perms(Status.permissions()) {}
Status::Status(StringRef Name, StringRef ExternalName, UniqueID UID,
sys::TimeValue MTime, uint32_t User, uint32_t Group,
uint64_t Size, file_type Type, perms Perms)
: Name(Name), ExternalName(ExternalName), UID(UID), MTime(MTime),
User(User), Group(Group), Size(Size), Type(Type), Perms(Perms) {}
bool Status::equivalent(const Status &Other) const {
return getUniqueID() == Other.getUniqueID();
}
bool Status::isDirectory() const {
return Type == file_type::directory_file;
}
bool Status::isRegularFile() const {
return Type == file_type::regular_file;
}
bool Status::isOther() const {
return exists() && !isRegularFile() && !isDirectory() && !isSymlink();
}
bool Status::isSymlink() const {
return Type == file_type::symlink_file;
}
bool Status::isStatusKnown() const {
return Type != file_type::status_error;
}
bool Status::exists() const {
return isStatusKnown() && Type != file_type::file_not_found;
}
File::~File() {}
FileSystem::~FileSystem() {}
error_code FileSystem::getBufferForFile(const llvm::Twine &Name,
OwningPtr<MemoryBuffer> &Result,
int64_t FileSize,
bool RequiresNullTerminator) {
llvm::OwningPtr<File> F;
if (error_code EC = openFileForRead(Name, F))
return EC;
error_code EC = F->getBuffer(Name, Result, FileSize, RequiresNullTerminator);
return EC;
}
//===-----------------------------------------------------------------------===/
// RealFileSystem implementation
//===-----------------------------------------------------------------------===/
/// \brief Wrapper around a raw file descriptor.
class RealFile : public File {
int FD;
friend class RealFileSystem;
RealFile(int FD) : FD(FD) {
assert(FD >= 0 && "Invalid or inactive file descriptor");
}
public:
~RealFile();
ErrorOr<Status> status() LLVM_OVERRIDE;
error_code getBuffer(const Twine &Name, OwningPtr<MemoryBuffer> &Result,
int64_t FileSize = -1,
bool RequiresNullTerminator = true) LLVM_OVERRIDE;
error_code close() LLVM_OVERRIDE;
};
RealFile::~RealFile() { close(); }
ErrorOr<Status> RealFile::status() {
assert(FD != -1 && "cannot stat closed file");
file_status RealStatus;
if (error_code EC = sys::fs::status(FD, RealStatus))
return EC;
return Status(RealStatus);
}
error_code RealFile::getBuffer(const Twine &Name,
OwningPtr<MemoryBuffer> &Result,
int64_t FileSize, bool RequiresNullTerminator) {
assert(FD != -1 && "cannot get buffer for closed file");
return MemoryBuffer::getOpenFile(FD, Name.str().c_str(), Result, FileSize,
RequiresNullTerminator);
}
// FIXME: This is terrible, we need this for ::close.
#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include <unistd.h>
#include <sys/uio.h>
#else
#include <io.h>
#ifndef S_ISFIFO
#define S_ISFIFO(x) (0)
#endif
#endif
error_code RealFile::close() {
if (::close(FD))
return error_code(errno, system_category());
FD = -1;
return error_code::success();
}
/// \brief The file system according to your operating system.
class RealFileSystem : public FileSystem {
public:
ErrorOr<Status> status(const Twine &Path) LLVM_OVERRIDE;
error_code openFileForRead(const Twine &Path,
OwningPtr<File> &Result) LLVM_OVERRIDE;
};
ErrorOr<Status> RealFileSystem::status(const Twine &Path) {
sys::fs::file_status RealStatus;
if (error_code EC = sys::fs::status(Path, RealStatus))
return EC;
Status Result(RealStatus);
Result.setName(Path.str());
Result.setExternalName(Path.str());
return Result;
}
error_code RealFileSystem::openFileForRead(const Twine &Name,
OwningPtr<File> &Result) {
int FD;
if (error_code EC = sys::fs::openFileForRead(Name, FD))
return EC;
Result.reset(new RealFile(FD));
return error_code::success();
}
IntrusiveRefCntPtr<FileSystem> vfs::getRealFileSystem() {
static IntrusiveRefCntPtr<FileSystem> FS = new RealFileSystem();
return FS;
}
//===-----------------------------------------------------------------------===/
// OverlayFileSystem implementation
//===-----------------------------------------------------------------------===/
OverlayFileSystem::OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> BaseFS) {
pushOverlay(BaseFS);
}
void OverlayFileSystem::pushOverlay(IntrusiveRefCntPtr<FileSystem> FS) {
FSList.push_back(FS);
}
ErrorOr<Status> OverlayFileSystem::status(const Twine &Path) {
// FIXME: handle symlinks that cross file systems
for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
ErrorOr<Status> Status = (*I)->status(Path);
if (Status || Status.getError() != errc::no_such_file_or_directory)
return Status;
}
return error_code(errc::no_such_file_or_directory, system_category());
}
error_code OverlayFileSystem::openFileForRead(const llvm::Twine &Path,
OwningPtr<File> &Result) {
// FIXME: handle symlinks that cross file systems
for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
error_code EC = (*I)->openFileForRead(Path, Result);
if (!EC || EC != errc::no_such_file_or_directory)
return EC;
}
return error_code(errc::no_such_file_or_directory, system_category());
}
//===-----------------------------------------------------------------------===/
// VFSFromYAML implementation
//===-----------------------------------------------------------------------===/
// Allow DenseMap<StringRef, ...>. This is useful below because we know all the
// strings are literals and will outlive the map, and there is no reason to
// store them.
namespace llvm {
template<>
struct DenseMapInfo<StringRef> {
// This assumes that "" will never be a valid key.
static inline StringRef getEmptyKey() { return StringRef(""); }
static inline StringRef getTombstoneKey() { return StringRef(); }
static unsigned getHashValue(StringRef Val) { return HashString(Val); }
static bool isEqual(StringRef LHS, StringRef RHS) { return LHS == RHS; }
};
}
namespace {
enum EntryKind {
EK_Directory,
EK_File
};
/// \brief A single file or directory in the VFS.
class Entry {
EntryKind Kind;
std::string Name;
public:
virtual ~Entry();
#if LLVM_HAS_RVALUE_REFERENCES
Entry(EntryKind K, std::string Name) : Kind(K), Name(std::move(Name)) {}
#endif
Entry(EntryKind K, StringRef Name) : Kind(K), Name(Name) {}
StringRef getName() const { return Name; }
EntryKind getKind() const { return Kind; }
};
class DirectoryEntry : public Entry {
std::vector<Entry *> Contents;
Status S;
public:
virtual ~DirectoryEntry();
#if LLVM_HAS_RVALUE_REFERENCES
DirectoryEntry(std::string Name, std::vector<Entry *> Contents, Status S)
: Entry(EK_Directory, std::move(Name)), Contents(std::move(Contents)),
S(std::move(S)) {}
#endif
DirectoryEntry(StringRef Name, ArrayRef<Entry *> Contents, const Status &S)
: Entry(EK_Directory, Name), Contents(Contents), S(S) {}
Status getStatus() { return S; }
typedef std::vector<Entry *>::iterator iterator;
iterator contents_begin() { return Contents.begin(); }
iterator contents_end() { return Contents.end(); }
static bool classof(const Entry *E) { return E->getKind() == EK_Directory; }
};
class FileEntry : public Entry {
std::string ExternalContentsPath;
public:
#if LLVM_HAS_RVALUE_REFERENCES
FileEntry(std::string Name, std::string ExternalContentsPath)
: Entry(EK_File, std::move(Name)),
ExternalContentsPath(std::move(ExternalContentsPath)) {}
#endif
FileEntry(StringRef Name, StringRef ExternalContentsPath)
: Entry(EK_File, Name), ExternalContentsPath(ExternalContentsPath) {}
StringRef getExternalContentsPath() const { return ExternalContentsPath; }
static bool classof(const Entry *E) { return E->getKind() == EK_File; }
};
/// \brief A virtual file system parsed from a YAML file.
///
/// Currently, this class allows creating virtual directories and mapping
/// virtual file paths to existing external files, available in \c ExternalFS.
///
/// The basic structure of the parsed file is:
/// \verbatim
/// {
/// 'version': <version number>,
/// <optional configuration>
/// 'roots': [
/// <directory entries>
/// ]
/// }
/// \endverbatim
///
/// All configuration options are optional.
/// 'case-sensitive': <boolean, default=true>
///
/// Virtual directories are represented as
/// \verbatim
/// {
/// 'type': 'directory',
/// 'name': <string>,
/// 'contents': [ <file or directory entries> ]
/// }
/// \endverbatim
///
/// The default attributes for virtual directories are:
/// \verbatim
/// MTime = now() when created
/// Perms = 0777
/// User = Group = 0
/// Size = 0
/// UniqueID = unspecified unique value
/// \endverbatim
///
/// Re-mapped files are represented as
/// \verbatim
/// {
/// 'type': 'file',
/// 'name': <string>,
/// 'external-contents': <path to external file>)
/// }
/// \endverbatim
///
/// and inherit their attributes from the external contents.
///
/// In both cases, the 'name' field must be a single path component (containing
/// no separators).
class VFSFromYAML : public vfs::FileSystem {
std::vector<Entry *> Roots; ///< The root(s) of the virtual file system.
/// \brief The file system to use for external references.
IntrusiveRefCntPtr<FileSystem> ExternalFS;
/// @name Configuration
/// @{
/// \brief Whether to perform case-sensitive comparisons.
///
/// Currently, case-insensitive matching only works correctly with ASCII.
bool CaseSensitive; ///< Whether to perform case-sensitive comparisons.
/// @}
friend class VFSFromYAMLParser;
private:
VFSFromYAML(IntrusiveRefCntPtr<FileSystem> ExternalFS)
: ExternalFS(ExternalFS), CaseSensitive(true) {}
/// \brief Looks up \p Path in \c Roots.
ErrorOr<Entry *> lookupPath(const Twine &Path);
/// \brief Looks up the path <tt>[Start, End)</tt> in \p From, possibly
/// recursing into the contents of \p From if it is a directory.
ErrorOr<Entry *> lookupPath(sys::path::const_iterator Start,
sys::path::const_iterator End, Entry *From);
public:
~VFSFromYAML();
/// \brief Parses \p Buffer, which is expected to be in YAML format and
/// returns a virtual file system representing its contents.
///
/// Takes ownership of \p Buffer.
static VFSFromYAML *create(MemoryBuffer *Buffer,
SourceMgr::DiagHandlerTy DiagHandler,
IntrusiveRefCntPtr<FileSystem> ExternalFS);
ErrorOr<Status> status(const Twine &Path) LLVM_OVERRIDE;
error_code openFileForRead(const Twine &Path,
OwningPtr<File> &Result) LLVM_OVERRIDE;
};
/// \brief A helper class to hold the common YAML parsing state.
class VFSFromYAMLParser {
yaml::Stream &Stream;
void error(yaml::Node *N, const Twine &Msg) {
Stream.printError(N, Msg);
}
// false on error
bool parseScalarString(yaml::Node *N, StringRef &Result,
SmallVectorImpl<char> &Storage) {
yaml::ScalarNode *S = dyn_cast<yaml::ScalarNode>(N);
if (!S) {
error(N, "expected string");
return false;
}
Result = S->getValue(Storage);
return true;
}
// false on error
bool parseScalarBool(yaml::Node *N, bool &Result) {
SmallString<5> Storage;
StringRef Value;
if (!parseScalarString(N, Value, Storage))
return false;
if (Value.equals_lower("true") || Value.equals_lower("on") ||
Value.equals_lower("yes") || Value == "1") {
Result = true;
return true;
} else if (Value.equals_lower("false") || Value.equals_lower("off") ||
Value.equals_lower("no") || Value == "0") {
Result = false;
return true;
}
error(N, "expected boolean value");
return false;
}
struct KeyStatus {
KeyStatus(bool Required=false) : Required(Required), Seen(false) {}
bool Required;
bool Seen;
};
typedef std::pair<StringRef, KeyStatus> KeyStatusPair;
// false on error
bool checkDuplicateOrUnknownKey(yaml::Node *KeyNode, StringRef Key,
DenseMap<StringRef, KeyStatus> &Keys) {
if (!Keys.count(Key)) {
error(KeyNode, "unknown key");
return false;
}
KeyStatus &S = Keys[Key];
if (S.Seen) {
error(KeyNode, Twine("duplicate key '") + Key + "'");
return false;
}
S.Seen = true;
return true;
}
// false on error
bool checkMissingKeys(yaml::Node *Obj, DenseMap<StringRef, KeyStatus> &Keys) {
for (DenseMap<StringRef, KeyStatus>::iterator I = Keys.begin(),
E = Keys.end();
I != E; ++I) {
if (I->second.Required && !I->second.Seen) {
error(Obj, Twine("missing key '") + I->first + "'");
return false;
}
}
return true;
}
Entry *parseEntry(yaml::Node *N) {
yaml::MappingNode *M = dyn_cast<yaml::MappingNode>(N);
if (!M) {
error(N, "expected mapping node for file or directory entry");
return NULL;
}
KeyStatusPair Fields[] = {
KeyStatusPair("name", true),
KeyStatusPair("type", true),
KeyStatusPair("contents", false),
KeyStatusPair("external-contents", false)
};
DenseMap<StringRef, KeyStatus> Keys(
&Fields[0], Fields + sizeof(Fields)/sizeof(Fields[0]));
bool HasContents = false; // external or otherwise
std::vector<Entry *> EntryArrayContents;
std::string ExternalContentsPath;
std::string Name;
EntryKind Kind;
for (yaml::MappingNode::iterator I = M->begin(), E = M->end(); I != E;
++I) {
StringRef Key;
// Reuse the buffer for key and value, since we don't look at key after
// parsing value.
SmallString<256> Buffer;
if (!parseScalarString(I->getKey(), Key, Buffer))
return NULL;
if (!checkDuplicateOrUnknownKey(I->getKey(), Key, Keys))
return NULL;
StringRef Value;
if (Key == "name") {
if (!parseScalarString(I->getValue(), Value, Buffer))
return NULL;
Name = Value;
if (sys::path::has_parent_path(Name)) {
error(I->getValue(), "unexpected path separator in name");
return NULL;
}
} else if (Key == "type") {
if (!parseScalarString(I->getValue(), Value, Buffer))
return NULL;
if (Value == "file")
Kind = EK_File;
else if (Value == "directory")
Kind = EK_Directory;
else {
error(I->getValue(), "unknown value for 'type'");
return NULL;
}
} else if (Key == "contents") {
if (HasContents) {
error(I->getKey(),
"entry already has 'contents' or 'external-contents'");
return NULL;
}
HasContents = true;
yaml::SequenceNode *Contents =
dyn_cast<yaml::SequenceNode>(I->getValue());
if (!Contents) {
// FIXME: this is only for directories, what about files?
error(I->getValue(), "expected array");
return NULL;
}
for (yaml::SequenceNode::iterator I = Contents->begin(),
E = Contents->end();
I != E; ++I) {
if (Entry *E = parseEntry(&*I))
EntryArrayContents.push_back(E);
else
return NULL;
}
} else if (Key == "external-contents") {
if (HasContents) {
error(I->getKey(),
"entry already has 'contents' or 'external-contents'");
return NULL;
}
HasContents = true;
if (!parseScalarString(I->getValue(), Value, Buffer))
return NULL;
ExternalContentsPath = Value;
} else {
llvm_unreachable("key missing from Keys");
}
}
if (Stream.failed())
return NULL;
// check for missing keys
if (!HasContents) {
error(N, "missing key 'contents' or 'external-contents'");
return NULL;
}
if (!checkMissingKeys(N, Keys))
return NULL;
switch (Kind) {
case EK_File:
return new FileEntry(llvm_move(Name), llvm_move(ExternalContentsPath));
case EK_Directory:
return new DirectoryEntry(
llvm_move(Name), llvm_move(EntryArrayContents),
Status("", "", getNextVirtualUniqueID(), sys::TimeValue::now(), 0, 0,
0, file_type::directory_file, sys::fs::all_all));
}
llvm_unreachable("unknown EntryKind in switch");
}
public:
VFSFromYAMLParser(yaml::Stream &S) : Stream(S) {}
// false on error
bool parse(yaml::Node *Root, VFSFromYAML *FS) {
yaml::MappingNode *Top = dyn_cast<yaml::MappingNode>(Root);
if (!Top) {
error(Root, "expected mapping node");
return false;
}
KeyStatusPair Fields[] = {
KeyStatusPair("version", true),
KeyStatusPair("case-sensitive", false),
KeyStatusPair("roots", true),
};
DenseMap<StringRef, KeyStatus> Keys(
&Fields[0], Fields + sizeof(Fields)/sizeof(Fields[0]));
// Parse configuration and 'roots'
for (yaml::MappingNode::iterator I = Top->begin(), E = Top->end(); I != E;
++I) {
SmallString<10> KeyBuffer;
StringRef Key;
if (!parseScalarString(I->getKey(), Key, KeyBuffer))
return false;
if (!checkDuplicateOrUnknownKey(I->getKey(), Key, Keys))
return false;
if (Key == "roots") {
yaml::SequenceNode *Roots = dyn_cast<yaml::SequenceNode>(I->getValue());
if (!Roots) {
error(I->getValue(), "expected array");
return false;
}
for (yaml::SequenceNode::iterator I = Roots->begin(), E = Roots->end();
I != E; ++I) {
if (Entry *E = parseEntry(&*I))
FS->Roots.push_back(E);
else
return false;
}
} else if (Key == "version") {
StringRef VersionString;
SmallString<4> Storage;
if (!parseScalarString(I->getValue(), VersionString, Storage))
return false;
int Version;
if (VersionString.getAsInteger<int>(10, Version)) {
error(I->getValue(), "expected integer");
return false;
}
if (Version < 0) {
error(I->getValue(), "invalid version number");
return false;
}
if (Version != 0) {
error(I->getValue(), "version mismatch, expected 0");
return false;
}
} else if (Key == "case-sensitive") {
if (!parseScalarBool(I->getValue(), FS->CaseSensitive))
return false;
} else {
llvm_unreachable("key missing from Keys");
}
}
if (Stream.failed())
return false;
if (!checkMissingKeys(Top, Keys))
return false;
return true;
}
};
} // end of anonymous namespace
Entry::~Entry() {}
DirectoryEntry::~DirectoryEntry() { llvm::DeleteContainerPointers(Contents); }
VFSFromYAML::~VFSFromYAML() { llvm::DeleteContainerPointers(Roots); }
VFSFromYAML *VFSFromYAML::create(MemoryBuffer *Buffer,
SourceMgr::DiagHandlerTy DiagHandler,
IntrusiveRefCntPtr<FileSystem> ExternalFS) {
SourceMgr SM;
yaml::Stream Stream(Buffer, SM);
SM.setDiagHandler(DiagHandler);
yaml::document_iterator DI = Stream.begin();
yaml::Node *Root = DI->getRoot();
if (DI == Stream.end() || !Root) {
SM.PrintMessage(SMLoc(), SourceMgr::DK_Error, "expected root node");
return NULL;
}
VFSFromYAMLParser P(Stream);
OwningPtr<VFSFromYAML> FS(new VFSFromYAML(ExternalFS));
if (!P.parse(Root, FS.get()))
return NULL;
return FS.take();
}
ErrorOr<Entry *> VFSFromYAML::lookupPath(const Twine &Path_) {
SmallVector<char, 256> Storage;
StringRef Path = Path_.toNullTerminatedStringRef(Storage);
if (Path.empty())
return error_code(errc::invalid_argument, system_category());
sys::path::const_iterator Start = sys::path::begin(Path);
sys::path::const_iterator End = sys::path::end(Path);
for (std::vector<Entry *>::iterator I = Roots.begin(), E = Roots.end();
I != E; ++I) {
ErrorOr<Entry *> Result = lookupPath(Start, End, *I);
if (Result || Result.getError() != errc::no_such_file_or_directory)
return Result;
}
return error_code(errc::no_such_file_or_directory, system_category());
}
ErrorOr<Entry *> VFSFromYAML::lookupPath(sys::path::const_iterator Start,
sys::path::const_iterator End,
Entry *From) {
// FIXME: handle . and ..
if (CaseSensitive ? !Start->equals(From->getName())
: !Start->equals_lower(From->getName()))
// failure to match
return error_code(errc::no_such_file_or_directory, system_category());
++Start;
if (Start == End) {
// Match!
return From;
}
DirectoryEntry *DE = dyn_cast<DirectoryEntry>(From);
if (!DE)
return error_code(errc::not_a_directory, system_category());
for (DirectoryEntry::iterator I = DE->contents_begin(),
E = DE->contents_end();
I != E; ++I) {
ErrorOr<Entry *> Result = lookupPath(Start, End, *I);
if (Result || Result.getError() != errc::no_such_file_or_directory)
return Result;
}
return error_code(errc::no_such_file_or_directory, system_category());
}
ErrorOr<Status> VFSFromYAML::status(const Twine &Path) {
ErrorOr<Entry *> Result = lookupPath(Path);
if (!Result)
return Result.getError();
std::string PathStr(Path.str());
if (FileEntry *F = dyn_cast<FileEntry>(*Result)) {
ErrorOr<Status> S = ExternalFS->status(F->getExternalContentsPath());
if (S) {
assert(S->getName() == S->getExternalName() &&
S->getName() == F->getExternalContentsPath());
S->setName(PathStr);
}
return S;
} else { // directory
DirectoryEntry *DE = cast<DirectoryEntry>(*Result);
Status S = DE->getStatus();
S.setName(PathStr);
S.setExternalName(PathStr);
return S;
}
}
error_code VFSFromYAML::openFileForRead(const Twine &Path,
OwningPtr<vfs::File> &Result) {
ErrorOr<Entry *> E = lookupPath(Path);
if (!E)
return E.getError();
FileEntry *F = dyn_cast<FileEntry>(*E);
if (!F) // FIXME: errc::not_a_file?
return error_code(errc::invalid_argument, system_category());
return ExternalFS->openFileForRead(Path, Result);
}
IntrusiveRefCntPtr<FileSystem>
vfs::getVFSFromYAML(MemoryBuffer *Buffer, SourceMgr::DiagHandlerTy DiagHandler,
IntrusiveRefCntPtr<FileSystem> ExternalFS) {
return VFSFromYAML::create(Buffer, DiagHandler, ExternalFS);
}
UniqueID vfs::getNextVirtualUniqueID() {
static volatile sys::cas_flag UID = 0;
sys::cas_flag ID = llvm::sys::AtomicIncrement(&UID);
// The following assumes that uint64_t max will never collide with a real
// dev_t value from the OS.
return UniqueID(std::numeric_limits<uint64_t>::max(), ID);
}
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