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/*-
* Copyright (c) 2014-2015 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __metadata_turtle --
* Return if a key's value should be taken from the turtle file.
*/
static int
__metadata_turtle(const char *key)
{
switch (key[0]) {
case 'f':
if (strcmp(key, WT_METAFILE_URI) == 0)
return (1);
break;
case 'W':
if (strcmp(key, "WiredTiger version") == 0)
return (1);
if (strcmp(key, "WiredTiger version string") == 0)
return (1);
break;
}
return (0);
}
/*
* __wt_metadata_open --
* Opens the metadata file, sets session->meta_dhandle.
*/
int
__wt_metadata_open(WT_SESSION_IMPL *session)
{
WT_BTREE *btree;
if (session->meta_dhandle != NULL)
return (0);
WT_RET(__wt_session_get_btree(session, WT_METAFILE_URI, NULL, NULL, 0));
session->meta_dhandle = session->dhandle;
WT_ASSERT(session, session->meta_dhandle != NULL);
/*
* Set special flags for the metadata file: eviction (the metadata file
* is in-memory and never evicted), logging (the metadata file is always
* logged if possible).
*
* Test flags before setting them so updates can't race in subsequent
* opens (the first update is safe because it's single-threaded from
* wiredtiger_open).
*/
btree = S2BT(session);
if (!F_ISSET(btree, WT_BTREE_IN_MEMORY))
F_SET(btree, WT_BTREE_IN_MEMORY);
if (!F_ISSET(btree, WT_BTREE_NO_EVICTION))
F_SET(btree, WT_BTREE_NO_EVICTION);
if (F_ISSET(btree, WT_BTREE_NO_LOGGING))
F_CLR(btree, WT_BTREE_NO_LOGGING);
/* The metadata handle doesn't need to stay locked -- release it. */
return (__wt_session_release_btree(session));
}
/*
* __wt_metadata_cursor --
* Opens a cursor on the metadata.
*/
int
__wt_metadata_cursor(
WT_SESSION_IMPL *session, const char *config, WT_CURSOR **cursorp)
{
WT_DATA_HANDLE *saved_dhandle;
WT_DECL_RET;
int is_dead;
const char *cfg[] =
{ WT_CONFIG_BASE(session, WT_SESSION_open_cursor), config, NULL };
saved_dhandle = session->dhandle;
WT_ERR(__wt_metadata_open(session));
session->dhandle = session->meta_dhandle;
/*
* We use the metadata a lot, so we have a handle cached; lock it and
* increment the in-use counter once the cursor is open.
*/
WT_ERR(__wt_session_lock_dhandle(session, 0, &is_dead));
/* The metadata should never be closed. */
WT_ASSERT(session, !is_dead);
WT_ERR(__wt_curfile_create(session, NULL, cfg, 0, 0, cursorp));
__wt_cursor_dhandle_incr_use(session);
/* Restore the caller's btree. */
err: session->dhandle = saved_dhandle;
return (ret);
}
/*
* __wt_metadata_insert --
* Insert a row into the metadata.
*/
int
__wt_metadata_insert(
WT_SESSION_IMPL *session, const char *key, const char *value)
{
WT_CURSOR *cursor;
WT_DECL_RET;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Insert: key: %s, value: %s, tracking: %s, %s" "turtle",
key, value, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
WT_RET_MSG(session, EINVAL,
"%s: insert not supported on the turtle file", key);
WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
cursor->set_key(cursor, key);
cursor->set_value(cursor, value);
WT_ERR(cursor->insert(cursor));
if (WT_META_TRACKING(session))
WT_ERR(__wt_meta_track_insert(session, key));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
/*
* __wt_metadata_update --
* Update a row in the metadata.
*/
int
__wt_metadata_update(
WT_SESSION_IMPL *session, const char *key, const char *value)
{
WT_CURSOR *cursor;
WT_DECL_RET;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Update: key: %s, value: %s, tracking: %s, %s" "turtle",
key, value, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
return (__wt_turtle_update(session, key, value));
if (WT_META_TRACKING(session))
WT_RET(__wt_meta_track_update(session, key));
WT_RET(__wt_metadata_cursor(session, "overwrite", &cursor));
cursor->set_key(cursor, key);
cursor->set_value(cursor, value);
WT_ERR(cursor->insert(cursor));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
/*
* __wt_metadata_remove --
* Remove a row from the metadata.
*/
int
__wt_metadata_remove(WT_SESSION_IMPL *session, const char *key)
{
WT_CURSOR *cursor;
WT_DECL_RET;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Remove: key: %s, tracking: %s, %s" "turtle",
key, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
WT_RET_MSG(session, EINVAL,
"%s: remove not supported on the turtle file", key);
WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
cursor->set_key(cursor, key);
WT_ERR(cursor->search(cursor));
if (WT_META_TRACKING(session))
WT_ERR(__wt_meta_track_update(session, key));
WT_ERR(cursor->remove(cursor));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
/*
* __wt_metadata_search --
* Return a copied row from the metadata.
* The caller is responsible for freeing the allocated memory.
*/
int
__wt_metadata_search(
WT_SESSION_IMPL *session, const char *key, char **valuep)
{
WT_CURSOR *cursor;
WT_DECL_RET;
const char *value;
*valuep = NULL;
WT_RET(__wt_verbose(session, WT_VERB_METADATA,
"Search: key: %s, tracking: %s, %s" "turtle",
key, WT_META_TRACKING(session) ? "true" : "false",
__metadata_turtle(key) ? "" : "not "));
if (__metadata_turtle(key))
return (__wt_turtle_read(session, key, valuep));
WT_RET(__wt_metadata_cursor(session, NULL, &cursor));
cursor->set_key(cursor, key);
WT_ERR(cursor->search(cursor));
WT_ERR(cursor->get_value(cursor, &value));
WT_ERR(__wt_strdup(session, value, valuep));
err: WT_TRET(cursor->close(cursor));
return (ret);
}
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