From 3f619478f796eddbba6e39502fe941b285dd97b1 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 20:00:34 +0200 Subject: Adding upstream version 1:10.11.6. Signed-off-by: Daniel Baumann --- storage/innobase/include/dyn0buf.h | 442 +++++++++++++++++++++++++++++++++++++ 1 file changed, 442 insertions(+) create mode 100644 storage/innobase/include/dyn0buf.h (limited to 'storage/innobase/include/dyn0buf.h') diff --git a/storage/innobase/include/dyn0buf.h b/storage/innobase/include/dyn0buf.h new file mode 100644 index 00000000..06af4dcc --- /dev/null +++ b/storage/innobase/include/dyn0buf.h @@ -0,0 +1,442 @@ +/***************************************************************************** + +Copyright (c) 2013, 2016, Oracle and/or its affiliates. All Rights Reserved. +Copyright (c) 2018, 2022, MariaDB Corporation. + +This program is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free Software +Foundation; version 2 of the License. + +This program is distributed in the hope that it will be useful, but WITHOUT +ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS +FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. + +You should have received a copy of the GNU General Public License along with +this program; if not, write to the Free Software Foundation, Inc., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA + +*****************************************************************************/ + +/**************************************************//** +@file include/dyn0buf.h +The dynamically allocated buffer implementation + +Created 2013-03-16 Sunny Bains +*******************************************************/ + +#ifndef dyn0buf_h +#define dyn0buf_h + +#include "mem0mem.h" +#include "dyn0types.h" +#include "ilist.h" + + +/** Class that manages dynamic buffers. It uses a UT_LIST of +mtr_buf_t::block_t instances. We don't use STL containers in +order to avoid the overhead of heap calls. Using a custom memory +allocator doesn't solve the problem either because we have to get +the memory from somewhere. We can't use the block_t::m_data as the +backend for the custom allocator because we would like the data in +the blocks to be contiguous. */ +class mtr_buf_t { +public: + /** SIZE - sizeof(m_node) + sizeof(m_used) */ + enum { MAX_DATA_SIZE = DYN_ARRAY_DATA_SIZE + - sizeof(ilist_node<>) + sizeof(uint32_t) }; + + class block_t : public ilist_node<> { + public: + + block_t() + { + compile_time_assert(MAX_DATA_SIZE <= (2 << 15)); + init(); + } + + /** + Gets the number of used bytes in a block. + @return number of bytes used */ + ulint used() const + MY_ATTRIBUTE((warn_unused_result)) + { + return(static_cast(m_used & ~DYN_BLOCK_FULL_FLAG)); + } + + /** + Gets pointer to the start of data. + @return pointer to data */ + byte* start() + MY_ATTRIBUTE((warn_unused_result)) + { + return(m_data); + } + + /** + @return start of data - non const version */ + byte* begin() + MY_ATTRIBUTE((warn_unused_result)) + { + return(m_data); + } + + /** + @return end of used data - non const version */ + byte* end() + MY_ATTRIBUTE((warn_unused_result)) + { + return(begin() + m_used); + } + + /** + @return start of data - const version */ + const byte* begin() const + MY_ATTRIBUTE((warn_unused_result)) + { + return(m_data); + } + + /** + @return end of used data - const version */ + const byte* end() const + MY_ATTRIBUTE((warn_unused_result)) + { + return(begin() + m_used); + } + + private: + /** + @return pointer to start of reserved space */ + template + Type push(uint32_t size) + { + Type ptr = reinterpret_cast(end()); + + m_used += size; + ut_ad(m_used <= uint32_t(MAX_DATA_SIZE)); + + return(ptr); + } + + /** + Grow the stack. */ + void close(const byte* ptr) + { + /* Check that it is within bounds */ + ut_ad(ptr >= begin()); + ut_ad(ptr <= begin() + m_buf_end); + + /* We have done the boundary check above */ + m_used = uint32_t(ptr - begin()); + + ut_ad(m_used <= MAX_DATA_SIZE); + ut_d(m_buf_end = 0); + } + + /** + Initialise the block */ + void init() + { + m_used = 0; + ut_d(m_buf_end = 0); + ut_d(m_magic_n = DYN_BLOCK_MAGIC_N); + } + private: +#ifdef UNIV_DEBUG + /** If opened then this is the buffer end offset, else 0 */ + ulint m_buf_end; + + /** Magic number (DYN_BLOCK_MAGIC_N) */ + ulint m_magic_n; +#endif /* UNIV_DEBUG */ + + /** Storage */ + byte m_data[MAX_DATA_SIZE]; + + /** number of data bytes used in this block; + DYN_BLOCK_FULL_FLAG is set when the block becomes full */ + uint32_t m_used; + + friend class mtr_buf_t; + }; + + typedef sized_ilist list_t; + + /** Default constructor */ + mtr_buf_t() + : + m_heap(), + m_size() + { + push_back(&m_first_block); + } + + /** Destructor */ + ~mtr_buf_t() + { + erase(); + } + + /** Reset the buffer vector */ + void erase() + { + if (m_heap != NULL) { + mem_heap_free(m_heap); + m_heap = NULL; + + /* Initialise the list and add the first block. */ + m_list.clear(); + m_list.push_back(m_first_block); + } else { + m_first_block.init(); + ut_ad(m_list.size() == 1); + } + + m_size = 0; + } + + /** + Makes room on top and returns a pointer to a buffer in it. After + copying the elements, the caller must close the buffer using close(). + @param size in bytes of the buffer; MUST be <= MAX_DATA_SIZE! + @return pointer to the buffer */ + byte* open(ulint size) + MY_ATTRIBUTE((warn_unused_result)) + { + ut_ad(size > 0); + ut_ad(size <= MAX_DATA_SIZE); + + block_t* block; + + block = has_space(size) ? back() : add_block(); + + ut_ad(block->m_used <= MAX_DATA_SIZE); + ut_d(block->m_buf_end = block->m_used + size); + + return(block->end()); + } + + /** + Closes the buffer returned by open. + @param ptr end of used space */ + void close(const byte* ptr) + { + ut_ad(!m_list.empty()); + block_t* block = back(); + + m_size -= block->used(); + + block->close(ptr); + + m_size += block->used(); + } + + /** + Makes room on top and returns a pointer to the added element. + The caller must copy the element to the pointer returned. + @param size in bytes of the element + @return pointer to the element */ + template + Type push(uint32_t size) + { + ut_ad(size > 0); + ut_ad(size <= MAX_DATA_SIZE); + + block_t* block; + + block = has_space(size) ? back() : add_block(); + + m_size += size; + + /* See ISO C++03 14.2/4 for why "template" is required. */ + + return(block->template push(size)); + } + + /** + Pushes n bytes. + @param str string to write + @param len string length */ + void push(const byte* ptr, uint32_t len) + { + while (len > 0) { + uint32_t n_copied = std::min(len, + uint32_t(MAX_DATA_SIZE)); + ::memmove(push(n_copied), ptr, n_copied); + + ptr += n_copied; + len -= n_copied; + } + } + + /** + Returns a pointer to an element in the buffer. const version. + @param pos position of element in bytes from start + @return pointer to element */ + template + const Type at(ulint pos) const + { + block_t* block = const_cast( + const_cast(this)->find(pos)); + + return(reinterpret_cast(block->begin() + pos)); + } + + /** + Returns a pointer to an element in the buffer. non const version. + @param pos position of element in bytes from start + @return pointer to element */ + template + Type at(ulint pos) + { + block_t* block = const_cast(find(pos)); + + return(reinterpret_cast(block->begin() + pos)); + } + + /** + Returns the size of the total stored data. + @return data size in bytes */ + ulint size() const + MY_ATTRIBUTE((warn_unused_result)) + { +#ifdef UNIV_DEBUG + ulint total_size = 0; + + for (list_t::iterator it = m_list.begin(), end = m_list.end(); + it != end; ++it) { + total_size += it->used(); + } + + ut_ad(total_size == m_size); +#endif /* UNIV_DEBUG */ + return(m_size); + } + + /** + Iterate over each block and call the functor. + @return false if iteration was terminated. */ + template + bool for_each_block(const Functor& functor) const + { + for (list_t::iterator it = m_list.begin(), end = m_list.end(); + it != end; ++it) { + + if (!functor(&*it)) { + return false; + } + } + + return(true); + } + + /** + @return the first block */ + block_t* front() + MY_ATTRIBUTE((warn_unused_result)) + { + return &m_list.front(); + } + + /** + @return true if m_first_block block was not filled fully */ + bool is_small() const + MY_ATTRIBUTE((warn_unused_result)) + { + return(m_heap == NULL); + } + + /** @return whether the buffer is empty */ + bool empty() const { return !back()->m_used; } + +private: + // Disable copying + mtr_buf_t(const mtr_buf_t&); + mtr_buf_t& operator=(const mtr_buf_t&); + + /** + Add the block to the end of the list*/ + void push_back(block_t* block) + { + block->init(); + m_list.push_back(*block); + } + + /** @return the last block in the list */ + block_t* back() const + { + return &const_cast(m_list.back()); + } + + /* + @return true if request can be fullfilled */ + bool has_space(ulint size) const + { + return(back()->m_used + size <= MAX_DATA_SIZE); + } + + /* + @return true if request can be fullfilled */ + bool has_space(ulint size) + { + return(back()->m_used + size <= MAX_DATA_SIZE); + } + + /** Find the block that contains the pos. + @param pos absolute offset, it is updated to make it relative + to the block + @return the block containing the pos. */ + block_t* find(ulint& pos) + { + ut_ad(!m_list.empty()); + + for (list_t::iterator it = m_list.begin(), end = m_list.end(); + it != end; ++it) { + + if (pos < it->used()) { + ut_ad(it->used() >= pos); + + return &*it; + } + + pos -= it->used(); + } + + return NULL; + } + + /** + Allocate and add a new block to m_list */ + block_t* add_block() + { + block_t* block; + + if (m_heap == NULL) { + m_heap = mem_heap_create(sizeof(*block)); + } + + block = reinterpret_cast( + mem_heap_alloc(m_heap, sizeof(*block))); + + push_back(block); + + return(block); + } + +private: + /** Heap to use for memory allocation */ + mem_heap_t* m_heap; + + /** Allocated blocks */ + list_t m_list; + + /** Total size used by all blocks */ + ulint m_size; + + /** The default block, should always be the first element. This + is for backwards compatibility and to avoid an extra heap allocation + for small REDO log records */ + block_t m_first_block; +}; + +#endif /* dyn0buf_h */ -- cgit v1.2.3