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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "chrome/browser/ash/file_system_provider/content_cache/local_fd.h"
#include "base/files/file_error_or.h"
#include "base/logging.h"
namespace ash::file_system_provider {
namespace {
base::FileErrorOr<std::unique_ptr<base::File>> WriteBytesBlocking(
std::unique_ptr<base::File> file,
const base::FilePath& path,
scoped_refptr<net::IOBuffer> buffer,
int64_t offset,
int length) {
VLOG(2) << "WriteBytesBlocking: {path = '" << path.value() << "', offset = '"
<< offset << "', length = '" << length << "'}";
if (!file) {
file = std::make_unique<base::File>(
path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_WRITE);
}
if (file->Write(offset, buffer->data(), length) != length) {
PLOG(ERROR) << "Failed to write bytes to file";
return base::unexpected(base::File::FILE_ERROR_FAILED);
}
return file;
}
FileErrorOrFileAndBytesRead ReadBytesBlocking(
std::unique_ptr<base::File> file,
const base::FilePath& path,
scoped_refptr<net::IOBuffer> buffer,
int64_t offset,
int length) {
if (!file) {
file = std::make_unique<base::File>(
path, base::File::FLAG_OPEN | base::File::FLAG_READ);
}
int bytes_read = file->Read(offset, buffer->data(), length);
if (bytes_read < 0) {
PLOG(ERROR) << "Failed to read bytes from file";
return base::unexpected(base::File::FILE_ERROR_FAILED);
}
VLOG(2) << "ReadBytesBlocking: {bytes_read = '" << bytes_read
<< "', file.GetLength = '" << file->GetLength() << "', offset = '"
<< offset << "', length = '" << length << "'}";
return std::make_pair(std::move(file), bytes_read);
}
} // namespace
LocalFD::LocalFD(
const base::FilePath& file_path,
scoped_refptr<base::SequencedTaskRunner> blocking_task_runner)
: file_path_(file_path), blocking_task_runner_(blocking_task_runner) {
VLOG(2) << "LocalFD instance created {file_path = '" << file_path_ << "'}";
}
LocalFD::~LocalFD() {
DCHECK(!in_progress_operation_)
<< "Operation still pending when FD destroyed";
VLOG(2) << "LocalFD instance destroyed {file_path = '" << file_path_
<< "'}";
if (file_) {
CloseFile();
}
}
void LocalFD::WriteBytes(
scoped_refptr<net::IOBuffer> buffer,
int64_t offset,
int length,
base::OnceCallback<void(base::File::Error)> callback) {
if (in_progress_operation_) {
std::move(callback).Run(base::File::FILE_ERROR_INVALID_OPERATION);
return;
}
in_progress_operation_ = true;
if (read_only_) {
// In the event we've only ever read from this file but we're now writing to
// the file, let's close the existing FD and instead start a new one that
// opens for write.
CloseFile();
}
read_only_ = false;
blocking_task_runner_->PostTaskAndReplyWithResult(
FROM_HERE,
base::BindOnce(&WriteBytesBlocking, std::move(file_), file_path_, buffer,
offset, length),
base::BindOnce(&LocalFD::OnBytesWritten, weak_ptr_factory_.GetWeakPtr(),
std::move(callback)));
}
void LocalFD::OnBytesWritten(
base::OnceCallback<void(base::File::Error)> callback,
FileErrorOrFile error_or_file) {
base::File::Error result = error_or_file.error_or(base::File::FILE_OK);
if (result == base::File::FILE_OK) {
CloseOrCacheFile(std::move(error_or_file.value()));
}
std::move(callback).Run(result);
}
void LocalFD::ReadBytes(scoped_refptr<net::IOBuffer> buffer,
int64_t offset,
int length,
FileErrorOrBytesReadCallback callback) {
if (in_progress_operation_) {
std::move(callback).Run(base::unexpected(base::File::FILE_ERROR_IN_USE));
return;
}
in_progress_operation_ = true;
blocking_task_runner_->PostTaskAndReplyWithResult(
FROM_HERE,
base::BindOnce(&ReadBytesBlocking, std::move(file_), file_path_, buffer,
offset, length),
base::BindOnce(&LocalFD::OnBytesRead, weak_ptr_factory_.GetWeakPtr(),
std::move(callback)));
}
void LocalFD::OnBytesRead(
FileErrorOrBytesReadCallback callback,
FileErrorOrFileAndBytesRead error_or_file_and_bytes_read) {
base::File::Error result =
error_or_file_and_bytes_read.error_or(base::File::FILE_OK);
if (result != base::File::FILE_OK) {
std::move(callback).Run(base::unexpected(result));
return;
}
auto [file, bytes_read] = std::move(error_or_file_and_bytes_read.value());
CloseOrCacheFile(std::move(file));
std::move(callback).Run(bytes_read);
}
void LocalFD::CloseOrCacheFile(std::unique_ptr<base::File> file) {
in_progress_operation_ = false;
if (!close_closure_.is_null()) {
VLOG(2) << "File closed whilst reading/writing, closing FD";
CloseFile();
} else {
VLOG(2) << "Caching FD for next operation";
file_ = std::move(file);
}
}
void LocalFD::Close(base::OnceClosure close_closure) {
DCHECK(close_closure_.is_null());
close_closure_ = std::move(close_closure);
if (in_progress_operation_) {
VLOG(2) << "FD is currently open, scheduling close";
return;
}
VLOG(2) << "Directly closing FD";
CloseFile();
}
void LocalFD::CloseFile() {
if (close_closure_) {
std::move(close_closure_).Run();
}
blocking_task_runner_->DeleteSoon(FROM_HERE, std::move(file_));
}
} // namespace ash::file_system_provider
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