1 files changed, 126 insertions, 0 deletions
diff --git a/storage/innobase/row/row0ext.cc b/storage/innobase/row/row0ext.cc
new file mode 100644
index 00000000000..8d4da9f034b
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+++ b/storage/innobase/row/row0ext.cc
@@ -0,0 +1,126 @@
+/*****************************************************************************
+
+Copyright (c) 2006, 2011, Oracle and/or its affiliates. All Rights Reserved.
+
+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, Suite 500, Boston, MA 02110-1335 USA
+
+*****************************************************************************/
+
+/**************************************************//**
+@file row/row0ext.cc
+Caching of externally stored column prefixes
+
+Created September 2006 Marko Makela
+*******************************************************/
+
+#include "row0ext.h"
+
+#ifdef UNIV_NONINL
+#include "row0ext.ic"
+#endif
+
+#include "btr0cur.h"
+
+/********************************************************************//**
+Fills the column prefix cache of an externally stored column. */
+static
+void
+row_ext_cache_fill(
+/*===============*/
+	row_ext_t*	ext,	/*!< in/out: column prefix cache */
+	ulint		i,	/*!< in: index of ext->ext[] */
+	ulint		zip_size,/*!< compressed page size in bytes, or 0 */
+	const dfield_t*	dfield)	/*!< in: data field */
+{
+	const byte*	field	= static_cast<const byte*>(
+					dfield_get_data(dfield));
+	ulint		f_len	= dfield_get_len(dfield);
+	byte*		buf	= ext->buf + i * ext->max_len;
+
+	ut_ad(ext->max_len > 0);
+	ut_ad(i < ext->n_ext);
+	ut_ad(dfield_is_ext(dfield));
+	ut_a(f_len >= BTR_EXTERN_FIELD_REF_SIZE);
+
+	if (UNIV_UNLIKELY(!memcmp(field_ref_zero,
+				  field + f_len - BTR_EXTERN_FIELD_REF_SIZE,
+				  BTR_EXTERN_FIELD_REF_SIZE))) {
+		/* The BLOB pointer is not set: we cannot fetch it */
+		ext->len[i] = 0;
+	} else {
+		/* Fetch at most ext->max_len of the column.
+		The column should be non-empty.  However,
+		trx_rollback_or_clean_all_recovered() may try to
+		access a half-deleted BLOB if the server previously
+		crashed during the execution of
+		btr_free_externally_stored_field(). */
+		ext->len[i] = btr_copy_externally_stored_field_prefix(
+			buf, ext->max_len, zip_size, field, f_len);
+	}
+}
+
+/********************************************************************//**
+Creates a cache of column prefixes of externally stored columns.
+@return	own: column prefix cache */
+UNIV_INTERN
+row_ext_t*
+row_ext_create(
+/*===========*/
+	ulint		n_ext,	/*!< in: number of externally stored columns */
+	const ulint*	ext,	/*!< in: col_no's of externally stored columns
+				in the InnoDB table object, as reported by
+				dict_col_get_no(); NOT relative to the records
+				in the clustered index */
+	ulint		flags,	/*!< in: table->flags */
+	const dtuple_t*	tuple,	/*!< in: data tuple containing the field
+				references of the externally stored
+				columns; must be indexed by col_no;
+				the clustered index record must be
+				covered by a lock or a page latch
+				to prevent deletion (rollback or purge). */
+	mem_heap_t*	heap)	/*!< in: heap where created */
+{
+	ulint		i;
+	ulint		zip_size = dict_tf_get_zip_size(flags);
+
+	row_ext_t*	ret;
+
+	ret = static_cast<row_ext_t*>(
+		mem_heap_alloc(heap,
+			       (sizeof *ret) + (n_ext - 1) * sizeof ret->len));
+
+	ut_ad(ut_is_2pow(zip_size));
+	ut_ad(zip_size <= UNIV_ZIP_SIZE_MAX);
+
+	ret->n_ext = n_ext;
+	ret->ext = ext;
+	ret->max_len = DICT_MAX_FIELD_LEN_BY_FORMAT_FLAG(flags);
+
+	ret->buf = static_cast<byte*>(
+		mem_heap_alloc(heap, n_ext * ret->max_len));
+
+#ifdef UNIV_DEBUG
+	memset(ret->buf, 0xaa, n_ext * ret->max_len);
+	UNIV_MEM_ALLOC(ret->buf, n_ext * ret->max_len);
+#endif
+
+	/* Fetch the BLOB prefixes */
+	for (i = 0; i < n_ext; i++) {
+		const dfield_t*	dfield;
+
+		dfield = dtuple_get_nth_field(tuple, ext[i]);
+		row_ext_cache_fill(ret, i, zip_size, dfield);
+	}
+
+	return(ret);
+}