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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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