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| 1 // Copyright 2013 The Chromium Authors. All rights reserved. | 1 // Copyright 2013 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef SQL_RECOVERY_H_ | 5 #ifndef SQL_RECOVERY_H_ |
| 6 #define SQL_RECOVERY_H_ | 6 #define SQL_RECOVERY_H_ |
| 7 | 7 |
| 8 #include "base/basictypes.h" | 8 #include "base/basictypes.h" |
| 9 | 9 |
| 10 #include "sql/connection.h" | 10 #include "sql/connection.h" |
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| 86 // database states are not well-understood without further | 86 // database states are not well-understood without further |
| 87 // diagnostics. Abandon recovery but do not raze the original | 87 // diagnostics. Abandon recovery but do not raze the original |
| 88 // database. | 88 // database. |
| 89 // NOTE(shess): Only call this when adding recovery support. In the | 89 // NOTE(shess): Only call this when adding recovery support. In the |
| 90 // steady state, all databases should progress to recovered or razed. | 90 // steady state, all databases should progress to recovered or razed. |
| 91 static void Rollback(scoped_ptr<Recovery> r); | 91 static void Rollback(scoped_ptr<Recovery> r); |
| 92 | 92 |
| 93 // Handle to the temporary recovery database. | 93 // Handle to the temporary recovery database. |
| 94 sql::Connection* db() { return &recover_db_; } | 94 sql::Connection* db() { return &recover_db_; } |
| 95 | 95 |
| 96 // Attempt to recover the named table from the corrupt database into | |
| 97 // the recovery database using a temporary recover virtual table. | |
| 98 // The virtual table schema is derived from the named table's schema | |
| 99 // in database [main]. Data is copied using INSERT OR REPLACE, so | |
| 100 // duplicates overwrite each other. | |
| 101 // | |
| 102 // |extend_columns| allows recovering tables which have excess | |
| 103 // columns relative to the target schema. The recover virtual table | |
| 104 // treats more data than specified as a sign of corruption. | |
| 105 // | |
| 106 // Returns true if all operations succeeded, with the number of rows | |
| 107 // recovered in |*rows_recovered|. | |
| 108 // | |
| 109 // NOTE(shess): Due to a flaw in the recovery virtual table, at this | |
| 110 // time this code injects the DEFAULT value of the target table in | |
| 111 // locations where the recovery table returns NULL. This is not | |
| 112 // entirely correct, because it happens both when there is a short | |
| 113 // row (correct) but also where there is an actual NULL value | |
| 114 // (incorrect). | |
| 115 // | |
| 116 // TODO(shess): Flag for INSERT OR REPLACE vs IGNORE. | |
| 117 // TODO(shess): Handle extended table names. | |
| 118 bool AutoRecoverTable(const char* table_name, | |
| 119 size_t extend_columns, | |
| 120 size_t* rows_recovered); | |
| 121 | |
| 122 // Setup a recover virtual table at temp.recover_meta, reading from | |
| 123 // corrupt.meta. Returns true if created. | |
| 124 // TODO(shess): Perhaps integrate into Begin(). | |
| 125 // TODO(shess): Add helpers to fetch additional items from the meta | |
| 126 // table as needed. | |
| 127 bool SetupMeta(); | |
| 128 | |
| 129 // Fetch the version number from temp.recover_meta. Returns false | |
| 130 // if the query fails, or if there is no version row. Otherwise | |
| 131 // returns true, with the version in |*version_number|. | |
| 132 // | |
| 133 // Only valid to call after successful SetupMeta(). | |
| 134 bool GetMetaVersionNumber(int* version_number); | |
| 135 | |
| 136 private: | 96 private: |
| 137 explicit Recovery(Connection* connection); | 97 explicit Recovery(Connection* connection); |
| 138 | 98 |
| 139 // Setup the recovery database handle for Begin(). Returns false in | 99 // Setup the recovery database handle for Begin(). Returns false in |
| 140 // case anything failed. | 100 // case anything failed. |
| 141 bool Init(const base::FilePath& db_path) WARN_UNUSED_RESULT; | 101 bool Init(const base::FilePath& db_path) WARN_UNUSED_RESULT; |
| 142 | 102 |
| 143 // Copy the recovered database over the original database. | 103 // Copy the recovered database over the original database. |
| 144 bool Backup() WARN_UNUSED_RESULT; | 104 bool Backup() WARN_UNUSED_RESULT; |
| 145 | 105 |
| 146 // Close the recovery database, and poison the original handle. | 106 // Close the recovery database, and poison the original handle. |
| 147 // |raze| controls whether the original database is razed or just | 107 // |raze| controls whether the original database is razed or just |
| 148 // poisoned. | 108 // poisoned. |
| 149 enum Disposition { | 109 enum Disposition { |
| 150 RAZE_AND_POISON, | 110 RAZE_AND_POISON, |
| 151 POISON, | 111 POISON, |
| 152 }; | 112 }; |
| 153 void Shutdown(Disposition raze); | 113 void Shutdown(Disposition raze); |
| 154 | 114 |
| 155 Connection* db_; // Original database connection. | 115 Connection* db_; // Original database connection. |
| 156 Connection recover_db_; // Recovery connection. | 116 Connection recover_db_; // Recovery connection. |
| 157 | 117 |
| 158 DISALLOW_COPY_AND_ASSIGN(Recovery); | 118 DISALLOW_COPY_AND_ASSIGN(Recovery); |
| 159 }; | 119 }; |
| 160 | 120 |
| 161 } // namespace sql | 121 } // namespace sql |
| 162 | 122 |
| 163 #endif // SQL_RECOVERY_H_ | 123 #endif // SQL_RECOVERY_H_ |
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