[sql] Use recover virtual table in sql::Recovery.

sql/recovery.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sql/recovery.h"
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/sparse_histogram.h"
 #include "sql/connection.h"
@@ skipping 54 matching lines @@
   // within the transaction context, because it would potentially
   // preserve any in-flight changes.  Unfortunately, any attach-based
   // system could not handle that.  A system which manually queried
   // one database and stored to the other possibly could, but would be
   // more complicated.
   db_->RollbackAllTransactions();
 
   if (!recover_db_.OpenTemporary())
     return false;
 
+  // TODO(shess): Figure out a story for USE_SYSTEM_SQLITE.  The
+  // virtual table implementation relies on SQLite internals for some
+  // types and functions, which could be copied inline to make it
+  // standalone.  Or an alternate implementation could try to read
+  // through errors entirely at the SQLite level.
+  //
+  // For now, defer to the caller.  The setup will succeed, but the
+  // later CREATE VIRTUAL TABLE call will fail, at which point the
+  // caller can fire Unrecoverable().
+#if !defined(USE_SYSTEM_SQLITE)
+  int rc = recoverVtableInit(recover_db_.db_);

[erikwright (departed), 2013/07/26 17:56:57]

Any compelling reason for sqlite to not always initialize this module for every
database?

[Scott Hess - ex-Googler, 2013/07/26 18:04:08]

Having SQLite initialize it would make it available to web content.  In the
abstract that's not a problem, but for now it felt like a line I didn't want to
cross.

+  if (rc != SQLITE_OK) {
+    LOG(ERROR) << "Failed to initialize recover module: "
+               << recover_db_.GetErrorMessage();
+    return false;
+  }
+#endif
+
   // Turn on |SQLITE_RecoveryMode| for the handle, which allows
   // reading certain broken databases.
   if (!recover_db_.Execute("PRAGMA writable_schema=1"))
     return false;
 
   if (!recover_db_.AttachDatabase(db_path, "corrupt"))
     return false;
 
   return true;
 }
@@ skipping 95 matching lines @@
   recover_db_.Close();
   if (raze == RAZE_AND_POISON) {
     db_->RazeAndClose();
   } else if (raze == POISON) {
     db_->Poison();
   }
   db_ = NULL;
 }
 
 }  // namespace sql