[sql] Prevent recovery against a closed database.

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 <stddef.h>
 
 #include "base/files/file_path.h"
 #include "base/format_macros.h"
@@ skipping 90 matching lines @@
   return false;
 #else
   return true;
 #endif
 }
 
 // static
 scoped_ptr<Recovery> Recovery::Begin(
     Connection* connection,
     const base::FilePath& db_path) {
+  // Recovery is likely to be used in error handling.  Since recovery changes
+  // the state of the handle, protect against multiple layers attempting the
+  // same recovery.
+  if (!connection->is_open()) {
+    // Warn about API mis-use.
+    DLOG_IF(FATAL, !connection->poisoned_)
+        << "Illegal to recover with closed database";
+    return scoped_ptr<Recovery>();
+  }
+
   scoped_ptr<Recovery> r(new Recovery(connection));
   if (!r->Init(db_path)) {
     // TODO(shess): Should Init() failure result in Raze()?
     r->Shutdown(POISON);
     return scoped_ptr<Recovery>();
   }
 
   return r;
 }
 
@@ skipping 406 matching lines @@
     }
     return false;
   }
 
   RecordRecoveryEvent(RECOVERY_SUCCESS_META_VERSION);
   *version = recovery_version.ColumnInt(0);
   return true;
 }
 
 }  // namespace sql