[sql] Recover Favicons v5 databases, with more recovery automation.

An entirely automated recovery system runs afoul of questions about
whether the corrupt database's schema can be trusted.
sql::Recovery::AutoRecoverTable() uses a schema created by the caller
to construct the recovery virtual table and then copies the data over.

sql::Recovery::SetupMeta() and GetMetaVersionNumber() simplify
accessing meta-table info in the corrupt database.

sql::test::IntegrityCheck() and CorruptSizeInHeader() helpers to
simplify common testing operations.

Rewrite ThumbnailDatabase v6 and v7 recovery code and tests using
these changes, and add a v5 recovery path.  Additionally handle
deprecated versions.

BUG=240396,109482

Review URL: https://codereview.chromium.org/50493012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235492 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 17 insertions, 0 deletions

diff --git a/sql/test/test_helpers.h b/sql/test/test_helpers.h
index 330f59a..b9d5e9b 100644
--- a/sql/test/test_helpers.h
+++ b/sql/test/test_helpers.h
@@ -5,6 +5,8 @@
 #ifndef SQL_TEST_TEST_HELPERS_H_
 #define SQL_TEST_TEST_HELPERS_H_
 
+#include <string>
+
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 
@@ -21,6 +23,16 @@ class Connection;
 namespace sql {
 namespace test {
 
+// SQLite stores the database size in the header, and if the actual
+// OS-derived size is smaller, the database is considered corrupt.
+// [This case is actually a common form of corruption in the wild.]
+// This helper sets the in-header size to one page larger than the
+// actual file size.  The resulting file will return SQLITE_CORRUPT
+// for most operations unless PRAGMA writable_schema is turned ON.
+//
+// Returns false if any error occurs accessing the file.
+bool CorruptSizeInHeader(const base::FilePath& db_path) WARN_UNUSED_RESULT;
+
 // Return the number of tables in sqlite_master.
 size_t CountSQLTables(sql::Connection* db) WARN_UNUSED_RESULT;
 
@@ -43,6 +55,11 @@ bool CountTableRows(sql::Connection* db, const char* table, size_t* count);
 bool CreateDatabaseFromSQL(const base::FilePath& db_path,
                            const base::FilePath& sql_path) WARN_UNUSED_RESULT;
 
+// Return the results of running "PRAGMA integrity_check" on |db|.
+// TODO(shess): sql::Connection::IntegrityCheck() is basically the
+// same, but not as convenient for testing.  Maybe combine.
+std::string IntegrityCheck(sql::Connection* db) WARN_UNUSED_RESULT;
+
 }  // namespace test
 }  // namespace sql