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Initial implementation of virtual file system

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This adds the minimum virtual file system support to start migrating
FileManager onto the VFS.

Originally discussed here:
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-February/035188.html

Differential Revision: http://llvm-reviews.chandlerc.com/D2745

llvm-svn: 201618
This commit is contained in:
Ben Langmuir
2014-02-19 00:10:30 +00:00
parent 064eaba99c
commit 090610d37a
16 changed files with 423 additions and 107 deletions
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44
clang/lib/Basic/FileSystemStatCache.cpp
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@@ -12,7 +12,7 @@
//===----------------------------------------------------------------------===//
#include "clang/Basic/FileSystemStatCache.h"
#include "llvm/Support/FileSystem.h"
#include "clang/Basic/VirtualFileSystem.h"
#include "llvm/Support/Path.h"
// FIXME: This is terrible, we need this for ::close.
@@ -30,13 +30,13 @@ using namespace clang;
void FileSystemStatCache::anchor() { }
static void copyStatusToFileData(const llvm::sys::fs::file_status &Status,
static void copyStatusToFileData(const vfs::Status &Status,
FileData &Data) {
Data.Size = Status.getSize();
Data.ModTime = Status.getLastModificationTime().toEpochTime();
Data.UniqueID = Status.getUniqueID();
Data.IsDirectory = is_directory(Status);
Data.IsNamedPipe = Status.type() == llvm::sys::fs::file_type::fifo_file;
Data.IsDirectory = Status.isDirectory();
Data.IsNamedPipe = Status.getType() == llvm::sys::fs::file_type::fifo_file;
Data.InPCH = false;
}
@@ -50,22 +50,23 @@ static void copyStatusToFileData(const llvm::sys::fs::file_status &Status,
/// implementation can optionally fill in FileDescriptor with a valid
/// descriptor and the client guarantees that it will close it.
bool FileSystemStatCache::get(const char *Path, FileData &Data, bool isFile,
int *FileDescriptor, FileSystemStatCache *Cache) {
vfs::File **F, FileSystemStatCache *Cache,
vfs::FileSystem &FS) {
LookupResult R;
bool isForDir = !isFile;
// If we have a cache, use it to resolve the stat query.
if (Cache)
R = Cache->getStat(Path, Data, isFile, FileDescriptor);
else if (isForDir || !FileDescriptor) {
R = Cache->getStat(Path, Data, isFile, F, FS);
else if (isForDir || !F) {
// If this is a directory or a file descriptor is not needed and we have
// no cache, just go to the file system.
llvm::sys::fs::file_status Status;
if (llvm::sys::fs::status(Path, Status)) {
llvm::ErrorOr<vfs::Status> Status = FS.status(Path);
if (!Status) {
R = CacheMissing;
} else {
R = CacheExists;
copyStatusToFileData(Status, Data);
copyStatusToFileData(*Status, Data);
}
} else {
// Otherwise, we have to go to the filesystem. We can always just use
@@ -75,7 +76,8 @@ bool FileSystemStatCache::get(const char *Path, FileData &Data, bool isFile,
//
// Because of this, check to see if the file exists with 'open'. If the
// open succeeds, use fstat to get the stat info.
llvm::error_code EC = llvm::sys::fs::openFileForRead(Path, *FileDescriptor);
llvm::OwningPtr<vfs::File> OwnedFile;
llvm::error_code EC = FS.openFileForRead(Path, OwnedFile);
if (EC) {
// If the open fails, our "stat" fails.
@@ -84,16 +86,16 @@ bool FileSystemStatCache::get(const char *Path, FileData &Data, bool isFile,
// Otherwise, the open succeeded. Do an fstat to get the information
// about the file. We'll end up returning the open file descriptor to the
// client to do what they please with it.
llvm::sys::fs::file_status Status;
if (!llvm::sys::fs::status(*FileDescriptor, Status)) {
llvm::ErrorOr<vfs::Status> Status = OwnedFile->status();
if (Status) {
R = CacheExists;
copyStatusToFileData(Status, Data);
copyStatusToFileData(*Status, Data);
*F = OwnedFile.take();
} else {
// fstat rarely fails. If it does, claim the initial open didn't
// succeed.
R = CacheMissing;
::close(*FileDescriptor);
*FileDescriptor = -1;
*F = 0;
}
}
}
@@ -105,9 +107,9 @@ bool FileSystemStatCache::get(const char *Path, FileData &Data, bool isFile,
// demands.
if (Data.IsDirectory != isForDir) {
// If not, close the file if opened.
if (FileDescriptor && *FileDescriptor != -1) {
::close(*FileDescriptor);
*FileDescriptor = -1;
if (F && *F) {
(*F)->close();
*F = 0;
}
return true;
@@ -118,8 +120,8 @@ bool FileSystemStatCache::get(const char *Path, FileData &Data, bool isFile,
MemorizeStatCalls::LookupResult
MemorizeStatCalls::getStat(const char *Path, FileData &Data, bool isFile,
int *FileDescriptor) {
LookupResult Result = statChained(Path, Data, isFile, FileDescriptor);
vfs::File **F, vfs::FileSystem &FS) {
LookupResult Result = statChained(Path, Data, isFile, F, FS);
// Do not cache failed stats, it is easy to construct common inconsistent
// situations if we do, and they are not important for PCH performance (which