Drizzled Public API Documentation

rename_table.cc
1 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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4  * Copyright (C) 2009 Sun Microsystems, Inc.
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19  */
20 
21 #include <config.h>
22 #include <drizzled/show.h>
23 #include <drizzled/lock.h>
24 #include <drizzled/session.h>
25 #include <drizzled/statement/rename_table.h>
26 #include <drizzled/pthread_globals.h>
27 #include <drizzled/plugin/storage_engine.h>
28 #include <drizzled/transaction_services.h>
29 #include <drizzled/sql_lex.h>
30 #include <drizzled/table/cache.h>
31 #include <drizzled/catalog/instance.h>
32 
33 namespace drizzled {
34 
36 {
37  TableList *first_table= (TableList *) lex().select_lex.table_list.first;
38  TableList *all_tables= lex().query_tables;
39  assert(first_table == all_tables && first_table != 0);
40  TableList *table;
41 
42  if (session().inTransaction())
43  {
44  my_error(ER_TRANSACTIONAL_DDL_NOT_SUPPORTED, MYF(0));
45  return true;
46  }
47 
48  for (table= first_table; table; table= table->next_local->next_local)
49  {
50  TableList old_list, new_list;
51  /*
52  we do not need initialize old_list and new_list because we will
53  come table[0] and table->next[0] there
54  */
55  old_list= table[0];
56  new_list= table->next_local[0];
57  }
58 
59  if (renameTables(first_table))
60  {
61  return true;
62  }
63 
64  return false;
65 }
66 
67 bool statement::RenameTable::renameTables(TableList *table_list)
68 {
69  bool error= true;
70  TableList *ren_table= NULL;
71 
72  /*
73  Avoid problems with a rename on a table that we have locked or
74  if the user is trying to to do this in a transcation context
75  */
76  if (session().inTransaction())
77  {
78  my_message(ER_LOCK_OR_ACTIVE_TRANSACTION, ER(ER_LOCK_OR_ACTIVE_TRANSACTION), MYF(0));
79  return true;
80  }
81 
82  if (session().wait_if_global_read_lock(false, true))
83  return true;
84 
85  {
86  boost::mutex::scoped_lock scopedLock(table::Cache::mutex()); /* Rename table lock for exclusive access */
87 
88  if (not session().lock_table_names_exclusively(table_list))
89  {
90  error= false;
91  ren_table= renameTablesInList(table_list, false);
92 
93  if (ren_table)
94  {
95  /* Rename didn't succeed; rename back the tables in reverse order */
96  TableList *table;
97 
98  /* Reverse the table list */
99  table_list= reverseTableList(table_list);
100 
101  /* Find the last renamed table */
102  for (table= table_list;
103  table->next_local != ren_table;
104  table= table->next_local->next_local)
105  { /* do nothing */ }
106 
107  table= table->next_local->next_local; // Skip error table
108 
109  /* Revert to old names */
110  renameTablesInList(table, true);
111  error= true;
112  }
113 
114  table_list->unlock_table_names();
115  }
116  }
117 
118  /* Lets hope this doesn't fail as the result will be messy */
119  if (not error)
120  {
121  TransactionServices::rawStatement(session(), *session().getQueryString(), *session().schema());
122  session().my_ok();
123  }
124 
125  session().startWaitingGlobalReadLock();
126 
127  return error;
128 }
129 
130 TableList *statement::RenameTable::reverseTableList(TableList *table_list)
131 {
132  TableList *prev= NULL;
133 
134  while (table_list)
135  {
136  TableList *next= table_list->next_local;
137  table_list->next_local= prev;
138  prev= table_list;
139  table_list= next;
140  }
141  return prev;
142 }
143 
144 bool statement::RenameTable::rename(TableList *ren_table,
145  const char *new_db,
146  const char *new_table_name,
147  bool skip_error)
148 {
149  bool rc= true;
150  const char *new_alias, *old_alias;
151 
152  {
153  old_alias= ren_table->getTableName();
154  new_alias= new_table_name;
155  }
156 
157  plugin::StorageEngine *engine= NULL;
158  message::table::shared_ptr table_message;
159 
160  identifier::Table old_identifier(session().catalog().identifier(),
161  ren_table->getSchemaName(),
162  old_alias,
163  message::Table::STANDARD);
164 
165  if (not (table_message= plugin::StorageEngine::getTableMessage(session(), old_identifier)))
166  {
167  my_error(ER_TABLE_UNKNOWN, old_identifier);
168  return true;
169  }
170 
171  engine= plugin::StorageEngine::findByName(session(), table_message->engine().name());
172 
173  identifier::Table new_identifier(session().catalog().identifier(),
174  new_db, new_alias, message::Table::STANDARD);
175  if (plugin::StorageEngine::doesTableExist(session(), new_identifier))
176  {
177  my_error(ER_TABLE_EXISTS_ERROR, new_identifier);
178  return 1; // This can't be skipped
179  }
180 
181  rc= rename_table(session(), engine, old_identifier, new_identifier);
182  if (rc && ! skip_error)
183  return true;
184 
185  return false;
186 }
187 
188 TableList *statement::RenameTable::renameTablesInList(TableList *table_list,
189  bool skip_error)
190 {
191  TableList *ren_table, *new_table;
192 
193  for (ren_table= table_list; ren_table; ren_table= new_table->next_local)
194  {
195  new_table= ren_table->next_local;
196  if (rename(ren_table, new_table->getSchemaName(), new_table->getTableName(), skip_error))
197  return ren_table;
198  }
199  return 0;
200 }
201 
202 } /* namespace drizzled */