[sql] Static helper to delete database and all associated files.

sql/connection.cc

 // Copyright (c) 2012 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/connection.h"
 
 #include <string.h>
 
 #include "base/files/file_path.h"
 #include "base/file_util.h"
@@ skipping 341 matching lines @@
   CloseInternal(true);
 
   // Mark the database so that future API calls fail appropriately,
   // but don't DCHECK (because after calling this function they are
   // expected to fail).
   poisoned_ = true;
 
   return result;
 }
 
+// TODO(shess): To the extent possible, figure out the optimal
+// ordering for these deletes which will prevent other connections
+// from seeing odd behavior.  For instance, it may be necessary to
+// manually lock the main database file in a SQLite-compatible fashion
+// (to prevent other processes from opening it), then delete the
+// journal files, then delete the main database file.  Another option
+// might be to lock the main database file and poison the header with
+// junk to prevent other processes from opening it successfully (like
+// Gears "SQLite poison 3" trick).
+//
+// static
+bool Connection::Delete(const base::FilePath& path) {
+  base::ThreadRestrictions::AssertIOAllowed();
+
+  base::FilePath journal_path(path.value() + FILE_PATH_LITERAL("-journal"));
+  base::FilePath wal_path(path.value() + FILE_PATH_LITERAL("-wal"));
+
+  file_util::Delete(journal_path, false);
+  file_util::Delete(wal_path, false);
+  file_util::Delete(path, false);
+
+  return !file_util::PathExists(journal_path) &&
+      !file_util::PathExists(wal_path) &&
+      !file_util::PathExists(path);
+}
+
 bool Connection::BeginTransaction() {
   if (needs_rollback_) {
     DCHECK_GT(transaction_nesting_, 0);
 
     // When we're going to rollback, fail on this begin and don't actually
     // mark us as entering the nested transaction.
     return false;
   }
 
   bool success = true;
@@ skipping 431 matching lines @@
   }
 
   // Best effort to put things back as they were before.
   const char kNoWritableSchema[] = "PRAGMA writable_schema = OFF";
   ignore_result(Execute(kNoWritableSchema));
 
   return ret;
 }
 
 }  // namespace sql