110 lines
2.8 KiB
C++
110 lines
2.8 KiB
C++
/*
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* Copyright (c) 2019, 2022, Oracle and/or its affiliates.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2.0,
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* as published by the Free Software Foundation.
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*
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* This program is also distributed with certain software (including
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* but not limited to OpenSSL) that is licensed under separate terms,
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* as designated in a particular file or component or in included license
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* documentation. The authors of MySQL hereby grant you an additional
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* permission to link the program and your derivative works with the
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* separately licensed software that they have included with MySQL.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License, version 2.0, for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#pragma once
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#include <assert.h>
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#include <cassert>
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#include <cstdint>
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#include <vector>
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// NOLINT(build/include_subdir)
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#include "encoding_pool.h"
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namespace protocol {
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class Encoding_buffer final {
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public:
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constexpr static uint32_t k_page_size = 4096;
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public:
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explicit Encoding_buffer(Encoding_pool *local_pool)
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: m_local_pool(local_pool) {
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assert(k_page_size == local_pool->get_page_size());
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m_front = m_current = m_local_pool->alloc_page();
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}
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~Encoding_buffer() {
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remove_page_list(m_front);
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m_front = m_current = nullptr;
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}
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Page *get_next_page() {
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auto page = m_local_pool->alloc_page();
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m_current->m_next_page = page;
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m_current = page;
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return m_current;
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}
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void remove_page_list(Page *page) {
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while (page) {
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auto page_to_delete = page;
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page = page_to_delete->m_next_page;
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m_local_pool->release_page(page_to_delete);
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}
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}
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template <uint32_t size> void ensure_buffer_size() {
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static_assert(size < k_page_size,
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"Page size might be too small to put those data in.");
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if (!m_current->is_at_least(size))
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get_next_page();
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}
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bool ensure_buffer_size(const uint32_t size) {
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if (!m_current->is_at_least(size)) {
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get_next_page();
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// Page size limits the number of bytes that
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// user can acquire in single call
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assert(m_current->is_at_least(size));
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return true;
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}
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return false;
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}
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inline bool is_empty() const {
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auto page = m_front;
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while (page) {
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if (page->get_used_bytes() > 0)
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return false;
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page = page->m_next_page;
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}
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return true;
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}
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Page *m_front;
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Page *m_current;
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private:
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Encoding_pool *const m_local_pool;
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};
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} // namespace protocol
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