Files
clang-p2996/lldb/source/Host/common/FileCache.cpp
Adrian Prantl 0642cd768b [lldb] Turn lldb_private::Status into a value type. (#106163)
This patch removes all of the Set.* methods from Status.

This cleanup is part of a series of patches that make it harder use the
anti-pattern of keeping a long-lives Status object around and updating
it while dropping any errors it contains on the floor.

This patch is largely NFC, the more interesting next steps this enables
is to:
1. remove Status.Clear()
2. assert that Status::operator=() never overwrites an error
3. remove Status::operator=()

Note that step (2) will bring 90% of the benefits for users, and step
(3) will dramatically clean up the error handling code in various
places. In the end my goal is to convert all APIs that are of the form

`    ResultTy DoFoo(Status& error)
`
to

`    llvm::Expected<ResultTy> DoFoo()
`
How to read this patch?

The interesting changes are in Status.h and Status.cpp, all other
changes are mostly

` perl -pi -e 's/\.SetErrorString/ = Status::FromErrorString/g' $(git
grep -l SetErrorString lldb/source)
`
plus the occasional manual cleanup.
2024-08-27 10:59:31 -07:00

118 lines
3.5 KiB
C++

//===-- FileCache.cpp -----------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "lldb/Host/FileCache.h"
#include "lldb/Host/File.h"
#include "lldb/Host/FileSystem.h"
using namespace lldb;
using namespace lldb_private;
FileCache *FileCache::m_instance = nullptr;
FileCache &FileCache::GetInstance() {
if (m_instance == nullptr)
m_instance = new FileCache();
return *m_instance;
}
lldb::user_id_t FileCache::OpenFile(const FileSpec &file_spec,
File::OpenOptions flags, uint32_t mode,
Status &error) {
if (!file_spec) {
error = Status::FromErrorString("empty path");
return UINT64_MAX;
}
auto file = FileSystem::Instance().Open(file_spec, flags, mode);
if (!file) {
error = file.takeError();
return UINT64_MAX;
}
lldb::user_id_t fd = file.get()->GetDescriptor();
m_cache[fd] = std::move(file.get());
return fd;
}
bool FileCache::CloseFile(lldb::user_id_t fd, Status &error) {
if (fd == UINT64_MAX) {
error = Status::FromErrorString("invalid file descriptor");
return false;
}
FDToFileMap::iterator pos = m_cache.find(fd);
if (pos == m_cache.end()) {
error = Status::FromErrorStringWithFormat(
"invalid host file descriptor %" PRIu64, fd);
return false;
}
FileUP &file_up = pos->second;
if (!file_up) {
error = Status::FromErrorString("invalid host backing file");
return false;
}
error = file_up->Close();
m_cache.erase(pos);
return error.Success();
}
uint64_t FileCache::WriteFile(lldb::user_id_t fd, uint64_t offset,
const void *src, uint64_t src_len,
Status &error) {
if (fd == UINT64_MAX) {
error = Status::FromErrorString("invalid file descriptor");
return UINT64_MAX;
}
FDToFileMap::iterator pos = m_cache.find(fd);
if (pos == m_cache.end()) {
error = Status::FromErrorStringWithFormat(
"invalid host file descriptor %" PRIu64, fd);
return false;
}
FileUP &file_up = pos->second;
if (!file_up) {
error = Status::FromErrorString("invalid host backing file");
return UINT64_MAX;
}
if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
error.Fail())
return UINT64_MAX;
size_t bytes_written = src_len;
error = file_up->Write(src, bytes_written);
if (error.Fail())
return UINT64_MAX;
return bytes_written;
}
uint64_t FileCache::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst,
uint64_t dst_len, Status &error) {
if (fd == UINT64_MAX) {
error = Status::FromErrorString("invalid file descriptor");
return UINT64_MAX;
}
FDToFileMap::iterator pos = m_cache.find(fd);
if (pos == m_cache.end()) {
error = Status::FromErrorStringWithFormat(
"invalid host file descriptor %" PRIu64, fd);
return false;
}
FileUP &file_up = pos->second;
if (!file_up) {
error = Status::FromErrorString("invalid host backing file");
return UINT64_MAX;
}
if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
error.Fail())
return UINT64_MAX;
size_t bytes_read = dst_len;
error = file_up->Read(dst, bytes_read);
if (error.Fail())
return UINT64_MAX;
return bytes_read;
}