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diff --git a/storage/innobase/mem/mem0mem.cc b/storage/innobase/mem/mem0mem.cc
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+++ b/storage/innobase/mem/mem0mem.cc
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+/*****************************************************************************
+
+Copyright (c) 1994, 2014, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2017, 2020, 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 mem/mem0mem.cc
+The memory management
+
+Created 6/9/1994 Heikki Tuuri
+*************************************************************************/
+
+#include "mem0mem.h"
+#include "buf0buf.h"
+#include "srv0srv.h"
+#include <stdarg.h>
+
+/**********************************************************************//**
+Concatenate two strings and return the result, using a memory heap.
+@return own: the result */
+char*
+mem_heap_strcat(
+/*============*/
+	mem_heap_t*	heap,	/*!< in: memory heap where string is allocated */
+	const char*	s1,	/*!< in: string 1 */
+	const char*	s2)	/*!< in: string 2 */
+{
+	char*	s;
+	ulint	s1_len = strlen(s1);
+	ulint	s2_len = strlen(s2);
+
+	s = static_cast<char*>(mem_heap_alloc(heap, s1_len + s2_len + 1));
+
+	memcpy(s, s1, s1_len);
+	memcpy(s + s1_len, s2, s2_len);
+
+	s[s1_len + s2_len] = '\0';
+
+	return(s);
+}
+
+
+/****************************************************************//**
+Helper function for mem_heap_printf.
+@return length of formatted string, including terminating NUL */
+static
+ulint
+mem_heap_printf_low(
+/*================*/
+	char*		buf,	/*!< in/out: buffer to store formatted string
+				in, or NULL to just calculate length */
+	const char*	format,	/*!< in: format string */
+	va_list		ap)	/*!< in: arguments */
+{
+	ulint 		len = 0;
+
+	while (*format) {
+
+		/* Does this format specifier have the 'l' length modifier. */
+		ibool	is_long = FALSE;
+
+		/* Length of one parameter. */
+		size_t	plen;
+
+		if (*format++ != '%') {
+			/* Non-format character. */
+
+			len++;
+
+			if (buf) {
+				*buf++ = *(format - 1);
+			}
+
+			continue;
+		}
+
+		if (*format == 'l') {
+			is_long = TRUE;
+			format++;
+		}
+
+		switch (*format++) {
+		case 's':
+			/* string */
+			{
+				char*	s = va_arg(ap, char*);
+
+				/* "%ls" is a non-sensical format specifier. */
+				ut_a(!is_long);
+
+				plen = strlen(s);
+				len += plen;
+
+				if (buf) {
+					memcpy(buf, s, plen);
+					buf += plen;
+				}
+			}
+
+			break;
+
+		case 'u':
+			/* unsigned int */
+			{
+				char		tmp[32];
+				unsigned long	val;
+
+				/* We only support 'long' values for now. */
+				ut_a(is_long);
+
+				val = va_arg(ap, unsigned long);
+
+				plen = size_t(sprintf(tmp, "%lu", val));
+				len += plen;
+
+				if (buf) {
+					memcpy(buf, tmp, plen);
+					buf += plen;
+				}
+			}
+
+			break;
+
+		case '%':
+
+			/* "%l%" is a non-sensical format specifier. */
+			ut_a(!is_long);
+
+			len++;
+
+			if (buf) {
+				*buf++ = '%';
+			}
+
+			break;
+
+		default:
+			ut_error;
+		}
+	}
+
+	/* For the NUL character. */
+	len++;
+
+	if (buf) {
+		*buf = '\0';
+	}
+
+	return(len);
+}
+
+/****************************************************************//**
+A simple sprintf replacement that dynamically allocates the space for the
+formatted string from the given heap. This supports a very limited set of
+the printf syntax: types 's' and 'u' and length modifier 'l' (which is
+required for the 'u' type).
+@return heap-allocated formatted string */
+char*
+mem_heap_printf(
+/*============*/
+	mem_heap_t*	heap,	/*!< in: memory heap */
+	const char*	format,	/*!< in: format string */
+	...)
+{
+	va_list		ap;
+	char*		str;
+	ulint 		len;
+
+	/* Calculate length of string */
+	len = 0;
+	va_start(ap, format);
+	len = mem_heap_printf_low(NULL, format, ap);
+	va_end(ap);
+
+	/* Now create it for real. */
+	str = static_cast<char*>(mem_heap_alloc(heap, len));
+	va_start(ap, format);
+	mem_heap_printf_low(str, format, ap);
+	va_end(ap);
+
+	return(str);
+}
+
+#ifdef UNIV_DEBUG
+/** Validates the contents of a memory heap.
+Checks a memory heap for consistency, prints the contents if any error
+is detected. A fatal error is logged if an error is detected.
+@param[in]	heap	Memory heap to validate. */
+void
+mem_heap_validate(
+	const mem_heap_t*	heap)
+{
+	ulint	size = 0;
+
+	for (const mem_block_t* block = heap;
+		block != NULL;
+		block = UT_LIST_GET_NEXT(list, block)) {
+
+		switch (block->type) {
+		case MEM_HEAP_DYNAMIC:
+			break;
+		case MEM_HEAP_BUFFER:
+		case MEM_HEAP_BUFFER | MEM_HEAP_BTR_SEARCH:
+			ut_ad(block->len <= srv_page_size);
+			break;
+		default:
+			ut_error;
+		}
+
+		size += block->len;
+	}
+
+	ut_ad(size == heap->total_size);
+}
+
+/** Copy the tail of a string.
+@param[in,out]	dst	destination buffer
+@param[in]	src	string whose tail to copy
+@param[in]	size	size of dst buffer, in bytes, including NUL terminator
+@return strlen(src) */
+static void ut_strlcpy_rev(char* dst, const char* src, ulint size)
+{
+	size_t src_size = strlen(src), n = std::min(src_size, size - 1);
+	memcpy(dst, src + src_size - n, n + 1);
+}
+#endif /* UNIV_DEBUG */
+
+/***************************************************************//**
+Creates a memory heap block where data can be allocated.
+@return own: memory heap block, NULL if did not succeed (only possible
+for MEM_HEAP_BTR_SEARCH type heaps) */
+mem_block_t*
+mem_heap_create_block_func(
+/*=======================*/
+	mem_heap_t*	heap,	/*!< in: memory heap or NULL if first block
+				should be created */
+	ulint		n,	/*!< in: number of bytes needed for user data */
+#ifdef UNIV_DEBUG
+	const char*	file_name,/*!< in: file name where created */
+	unsigned	line,	/*!< in: line where created */
+#endif /* UNIV_DEBUG */
+	ulint		type)	/*!< in: type of heap: MEM_HEAP_DYNAMIC or
+				MEM_HEAP_BUFFER */
+{
+	buf_block_t*	buf_block = NULL;
+	mem_block_t*	block;
+	ulint		len;
+
+	ut_ad((type == MEM_HEAP_DYNAMIC) || (type == MEM_HEAP_BUFFER)
+	      || (type == MEM_HEAP_BUFFER + MEM_HEAP_BTR_SEARCH));
+
+	if (heap != NULL) {
+		ut_d(mem_heap_validate(heap));
+	}
+
+	/* In dynamic allocation, calculate the size: block header + data. */
+	len = MEM_BLOCK_HEADER_SIZE + MEM_SPACE_NEEDED(n);
+
+	if (type == MEM_HEAP_DYNAMIC || len < srv_page_size / 2) {
+
+		ut_ad(type == MEM_HEAP_DYNAMIC || n <= MEM_MAX_ALLOC_IN_BUF);
+
+		block = static_cast<mem_block_t*>(ut_malloc_nokey(len));
+	} else {
+		len = srv_page_size;
+
+		if ((type & MEM_HEAP_BTR_SEARCH) && heap) {
+			/* We cannot allocate the block from the
+			buffer pool, but must get the free block from
+			the heap header free block field */
+
+			buf_block = static_cast<buf_block_t*>(heap->free_block);
+			heap->free_block = NULL;
+
+			if (UNIV_UNLIKELY(!buf_block)) {
+
+				return(NULL);
+			}
+		} else {
+			buf_block = buf_block_alloc();
+		}
+
+		block = (mem_block_t*) buf_block->frame;
+	}
+
+	if (block == NULL) {
+		ib::fatal() << "Unable to allocate memory of size "
+			<< len << ".";
+	}
+
+	block->buf_block = buf_block;
+	block->free_block = NULL;
+
+	ut_d(ut_strlcpy_rev(block->file_name, file_name,
+			    sizeof(block->file_name)));
+	ut_d(block->line = line);
+
+	mem_block_set_len(block, len);
+	mem_block_set_type(block, type);
+	mem_block_set_free(block, MEM_BLOCK_HEADER_SIZE);
+	mem_block_set_start(block, MEM_BLOCK_HEADER_SIZE);
+
+	if (UNIV_UNLIKELY(heap == NULL)) {
+		/* This is the first block of the heap. The field
+		total_size should be initialized here */
+		block->total_size = len;
+	} else {
+		/* Not the first allocation for the heap. This block's
+		total_length field should be set to undefined. */
+		ut_d(block->total_size = ULINT_UNDEFINED);
+		MEM_UNDEFINED(&block->total_size, sizeof block->total_size);
+
+		heap->total_size += len;
+	}
+
+	/* Poison all available memory. Individual chunks will be unpoisoned on
+	every mem_heap_alloc() call. */
+	compile_time_assert(MEM_BLOCK_HEADER_SIZE >= sizeof *block);
+	MEM_NOACCESS(block + 1, len - sizeof *block);
+
+	ut_ad((ulint)MEM_BLOCK_HEADER_SIZE < len);
+
+	return(block);
+}
+
+/***************************************************************//**
+Adds a new block to a memory heap.
+@return created block, NULL if did not succeed (only possible for
+MEM_HEAP_BTR_SEARCH type heaps) */
+mem_block_t*
+mem_heap_add_block(
+/*===============*/
+	mem_heap_t*	heap,	/*!< in: memory heap */
+	ulint		n)	/*!< in: number of bytes user needs */
+{
+	mem_block_t*	block;
+	mem_block_t*	new_block;
+	ulint		new_size;
+
+	block = UT_LIST_GET_LAST(heap->base);
+
+	/* We have to allocate a new block. The size is always at least
+	doubled until the standard size is reached. After that the size
+	stays the same, except in cases where the caller needs more space. */
+
+	new_size = 2 * mem_block_get_len(block);
+
+	if (heap->type != MEM_HEAP_DYNAMIC) {
+		/* From the buffer pool we allocate buffer frames */
+		ut_a(n <= MEM_MAX_ALLOC_IN_BUF);
+
+		if (new_size > MEM_MAX_ALLOC_IN_BUF) {
+			new_size = MEM_MAX_ALLOC_IN_BUF;
+		}
+	} else if (new_size > MEM_BLOCK_STANDARD_SIZE) {
+
+		new_size = MEM_BLOCK_STANDARD_SIZE;
+	}
+
+	if (new_size < n) {
+		new_size = n;
+	}
+
+	new_block = mem_heap_create_block(heap, new_size, heap->type,
+					  heap->file_name, heap->line);
+	if (new_block == NULL) {
+
+		return(NULL);
+	}
+
+	/* Add the new block as the last block */
+
+	UT_LIST_INSERT_AFTER(heap->base, block, new_block);
+
+	return(new_block);
+}
+
+/******************************************************************//**
+Frees a block from a memory heap. */
+void
+mem_heap_block_free(
+/*================*/
+	mem_heap_t*	heap,	/*!< in: heap */
+	mem_block_t*	block)	/*!< in: block to free */
+{
+	ulint		type;
+	ulint		len;
+	buf_block_t*	buf_block;
+
+	buf_block = static_cast<buf_block_t*>(block->buf_block);
+
+	UT_LIST_REMOVE(heap->base, block);
+
+	ut_ad(heap->total_size >= block->len);
+	heap->total_size -= block->len;
+
+	type = heap->type;
+	len = block->len;
+
+	if (type == MEM_HEAP_DYNAMIC || len < srv_page_size / 2) {
+		ut_ad(!buf_block);
+		ut_free(block);
+	} else {
+		ut_ad(type & MEM_HEAP_BUFFER);
+		buf_block_free(buf_block);
+	}
+}
+
+/******************************************************************//**
+Frees the free_block field from a memory heap. */
+void
+mem_heap_free_block_free(
+/*=====================*/
+	mem_heap_t*	heap)	/*!< in: heap */
+{
+	if (UNIV_LIKELY_NULL(heap->free_block)) {
+
+		buf_block_free(static_cast<buf_block_t*>(heap->free_block));
+
+		heap->free_block = NULL;
+	}
+}