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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.
#include "chrome/browser/ash/fileapi/copy_from_fd.h"
#include "base/posix/eintr_wrapper.h"
#include "base/task/thread_pool.h"
#include "base/threading/scoped_blocking_call.h"
#include "content/public/browser/browser_thread.h"
#include "net/base/io_buffer.h"
namespace ash {
namespace {
int ReadFromScopedFDOffTheIOThread(int fd,
scoped_refptr<net::IOBuffer> buffer) {
base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
base::BlockingType::MAY_BLOCK);
char* ptr = buffer->data();
int len = buffer->size();
ssize_t n = HANDLE_EINTR(read(fd, ptr, len));
return (n >= 0) ? static_cast<int>(n)
: static_cast<int>(net::Error::ERR_FAILED);
}
class FromFDCopier {
public:
FromFDCopier(base::ScopedFD src_scoped_fd,
std::unique_ptr<storage::FileStreamWriter> dst_fs_writer,
storage::FlushPolicy dst_flush_policy,
CopyFromFileDescriptorCallback callback);
void CallRead();
private:
// For the "int result" arguments: If negative, it's a net error code. If
// non-negative, it's the number of bytes read.
void OnRead(int result);
void CallWrite(int result);
void MaybeFlush(int result);
void Finish(int result);
static constexpr size_t kBufferLen = 65536;
base::ScopedFD scoped_fd_;
std::unique_ptr<storage::FileStreamWriter> fs_writer_;
storage::FlushPolicy dst_flush_policy_;
CopyFromFileDescriptorCallback callback_;
scoped_refptr<net::IOBuffer> buffer_;
scoped_refptr<net::DrainableIOBuffer> drainable_buffer_;
};
FromFDCopier::FromFDCopier(
base::ScopedFD src_scoped_fd,
std::unique_ptr<storage::FileStreamWriter> dst_fs_writer,
storage::FlushPolicy dst_flush_policy,
CopyFromFileDescriptorCallback callback)
: scoped_fd_(std::move(src_scoped_fd)),
fs_writer_(std::move(dst_fs_writer)),
dst_flush_policy_(dst_flush_policy),
callback_(std::move(callback)),
buffer_(base::MakeRefCounted<net::IOBufferWithSize>(kBufferLen)) {}
void FromFDCopier::CallRead() {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
base::ThreadPool::PostTaskAndReplyWithResult(
FROM_HERE, {base::MayBlock()},
base::BindOnce(&ReadFromScopedFDOffTheIOThread, scoped_fd_.get(),
buffer_),
base::BindOnce(&FromFDCopier::OnRead,
// base::Unretained is safe because |this| isn't deleted
// until Finish is called.
base::Unretained(this)));
}
void FromFDCopier::OnRead(int result) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
CHECK(!drainable_buffer_);
if (result <= 0) {
MaybeFlush(result);
return;
}
drainable_buffer_ = base::MakeRefCounted<net::DrainableIOBuffer>(
buffer_, static_cast<size_t>(result));
CallWrite(0);
}
void FromFDCopier::CallWrite(int result) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
CHECK(drainable_buffer_);
while (true) {
if (result < 0) {
MaybeFlush(result);
return;
}
drainable_buffer_->DidConsume(result);
if (drainable_buffer_->BytesRemaining() <= 0) {
drainable_buffer_.reset();
CallRead();
return;
}
result = fs_writer_->Write(
drainable_buffer_.get(), drainable_buffer_->BytesRemaining(),
base::BindOnce(&FromFDCopier::CallWrite,
// base::Unretained is safe because |this|
// isn't deleted until Finish is called.
base::Unretained(this)));
if (result == net::ERR_IO_PENDING) { // The write was asynchronous.
return;
}
}
}
void FromFDCopier::MaybeFlush(int result) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
if ((result >= 0) &&
(dst_flush_policy_ == storage::FlushPolicy::FLUSH_ON_COMPLETION)) {
result = fs_writer_->Flush(
storage::FlushMode::kEndOfFile,
base::BindOnce(&FromFDCopier::Finish,
// base::Unretained is safe because |this|
// isn't deleted until Finish is called.
base::Unretained(this)));
if (result == net::ERR_IO_PENDING) { // The flush was asynchronous.
return;
}
}
Finish(result);
}
void FromFDCopier::Finish(int result) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
std::move(callback_).Run(
std::move(scoped_fd_), std::move(fs_writer_),
(result >= 0) ? net::OK : static_cast<net::Error>(result));
delete this;
}
} // namespace
void CopyFromFileDescriptor(
base::ScopedFD src_scoped_fd,
std::unique_ptr<storage::FileStreamWriter> dst_fs_writer,
storage::FlushPolicy dst_flush_policy,
CopyFromFileDescriptorCallback callback) {
DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
if (!callback) {
return;
} else if (!src_scoped_fd.is_valid() || !dst_fs_writer) {
std::move(callback).Run(std::move(src_scoped_fd), std::move(dst_fs_writer),
net::Error::ERR_INVALID_ARGUMENT);
return;
}
// This new-ly created object is deleted in FromFDCopier::Finish.
FromFDCopier* copier =
new FromFDCopier(std::move(src_scoped_fd), std::move(dst_fs_writer),
dst_flush_policy, std::move(callback));
copier->CallRead();
}
} // namespace ash
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