7b1f433aed
Move the get() logic in fstream.cc into the file::dma_read_bulk()
fixing some issues:
- Fix the funny "alignment" calculation.
- Make sure the length is aligned too.
- Added new functions:
- dma_read(pos, len): returns a temporary_buffer with read data and
doesn't assume/require any alignment from either "pos"
or "len". Unlike dma_read_bulk() this function will
trim the resulting buffer to the requested size.
- dma_read_exactly(pos, len): does exactly what dma_read(pos, len) does but it
will also throw and exception if it failed to read
the required number of bytes (e.g. EOF is reached).
- Changed the names of parameters of dma_read(pos, buf, len) in order to emphasize
that they have to be aligned.
- Added a description to dma_read(pos, buf, len) to make it even more clear.
Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>
130 lines
4.4 KiB
C++
130 lines
4.4 KiB
C++
/*
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* This file is open source software, licensed to you under the terms
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* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
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* distributed with this work for additional information regarding copyright
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* ownership. You may not use this file except in compliance with the License.
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*
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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/*
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* Copyright (C) 2015 Cloudius Systems, Ltd.
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*/
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#include "fstream.hh"
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#include "align.hh"
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#include <malloc.h>
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#include <string.h>
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class file_data_source_impl : public data_source_impl {
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lw_shared_ptr<file> _file;
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uint64_t _pos;
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std::experimental::optional<size_t> _fsize;
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size_t _buffer_size;
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private:
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// Should be called only when _fsize is initialized
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future<temporary_buffer<char>> do_get() {
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using buf_type = temporary_buffer<char>;
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if (_pos >= _fsize.value()) {
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return make_ready_future<buf_type>(std::move(buf_type(0)));
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}
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return _file->dma_read_bulk<char>(_pos, _buffer_size).then(
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[this] (buf_type buf) {
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_pos += buf.size();
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return std::move(buf);
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});
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}
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public:
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file_data_source_impl(lw_shared_ptr<file> f, uint64_t pos, size_t buffer_size)
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: _file(std::move(f)), _pos(pos), _buffer_size(buffer_size) {}
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virtual future<temporary_buffer<char>> get() override {
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if (!_fsize){
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return _file->size().then(
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[this] (size_t fsize) {
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_fsize = fsize;
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return do_get();
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});
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}
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return do_get();
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}
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};
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class file_data_source : public data_source {
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public:
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file_data_source(lw_shared_ptr<file> f, uint64_t offset, size_t buffer_size)
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: data_source(std::make_unique<file_data_source_impl>(
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std::move(f), offset, buffer_size)) {}
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};
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input_stream<char> make_file_input_stream(
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lw_shared_ptr<file> f, uint64_t offset, size_t buffer_size) {
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return input_stream<char>(file_data_source(std::move(f), offset, buffer_size));
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}
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class file_data_sink_impl : public data_sink_impl {
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lw_shared_ptr<file> _file;
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size_t _buffer_size;
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uint64_t _pos = 0;
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public:
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file_data_sink_impl(lw_shared_ptr<file> f, size_t buffer_size)
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: _file(std::move(f)), _buffer_size(buffer_size) {}
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future<> put(net::packet data) { return make_ready_future<>(); }
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virtual temporary_buffer<char> allocate_buffer(size_t size) override {
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// buffers to dma_write must be aligned to 512 bytes.
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return temporary_buffer<char>::aligned(512, size);
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}
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virtual future<> put(temporary_buffer<char> buf) override {
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bool truncate = false;
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auto pos = _pos;
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_pos += buf.size();
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auto p = static_cast<const char*>(buf.get());
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size_t buf_size = buf.size();
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if ((buf.size() & 511) != 0) {
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// If buf size isn't aligned, copy its content into a new aligned buf.
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// This should only happen when the user calls output_stream::flush().
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auto tmp = allocate_buffer(align_up(buf.size(), 512UL));
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::memcpy(tmp.get_write(), buf.get(), buf.size());
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buf = std::move(tmp);
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p = buf.get();
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buf_size = buf.size();
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truncate = true;
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}
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return _file->dma_write(pos, p, buf_size).then(
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[this, buf = std::move(buf), truncate] (size_t size) {
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if (truncate) {
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return _file->truncate(_pos).then([this] {
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return _file->flush();
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});
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}
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return make_ready_future<>();
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});
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}
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future<> close() { return _file->flush(); }
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};
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class file_data_sink : public data_sink {
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public:
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file_data_sink(lw_shared_ptr<file> f, size_t buffer_size)
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: data_sink(std::make_unique<file_data_sink_impl>(
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std::move(f), buffer_size)) {}
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};
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output_stream<char> make_file_output_stream(lw_shared_ptr<file> f, size_t buffer_size) {
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return output_stream<char>(file_data_sink(std::move(f), buffer_size), buffer_size);
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}
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