[sql] Allow restricting database to user read access.

sql/connection.h

 // 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.
 
 #ifndef SQL_CONNECTION_H_
 #define SQL_CONNECTION_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 98 matching lines @@
   // transaition (requires another access to the DB) and because we don't
   // actually need it.
   //
   // Exclusive mode means that the database is not unlocked at the end of each
   // transaction, which means there may be less time spent initializing the
   // next transaction because it doesn't have to re-aquire locks.
   //
   // This must be called before Open() to have an effect.
   void set_exclusive_locking() { exclusive_locking_ = true; }
 
+  // Call to cause Open() to restrict access permissions of the
+  // database file to only the owner.
+  // TODO(shess): Currently only supported on OS_POSIX.

[Ilya Sherman, 2013/07/16 22:35:52]

nit: Mebbe clarify that this is a no-op on other platforms?

[Scott Hess - ex-Googler, 2013/07/17 00:25:37]

Done.

+  void set_restrict_to_user() { restrict_to_user_ = true; }
+
   // Set an error-handling callback.  On errors, the error number (and
   // statement, if available) will be passed to the callback.
   //
   // If no callback is set, the default action is to crash in debug
   // mode or return failure in release mode.
   typedef base::Callback<void(int, Statement*)> ErrorCallback;
   void set_error_callback(const ErrorCallback& callback) {
     error_callback_ = callback;
   }
   bool has_error_callback() const {
@@ skipping 345 matching lines @@
 
   // The actual sqlite database. Will be NULL before Init has been called or if
   // Init resulted in an error.
   sqlite3* db_;
 
   // Parameters we'll configure in sqlite before doing anything else. Zero means
   // use the default value.
   int page_size_;
   int cache_size_;
   bool exclusive_locking_;
+  bool restrict_to_user_;
 
   // All cached statements. Keeping a reference to these statements means that
   // they'll remain active.
   typedef std::map<StatementID, scoped_refptr<StatementRef> >
       CachedStatementMap;
   CachedStatementMap statement_cache_;
 
   // A list of all StatementRefs we've given out. Each ref must register with
   // us when it's created or destroyed. This allows us to potentially close
   // any open statements when we encounter an error.
@@ skipping 22 matching lines @@
 
   // Tag for auxiliary histograms.
   std::string histogram_tag_;
 
   DISALLOW_COPY_AND_ASSIGN(Connection);
 };
 
 }  // namespace sql
 
 #endif  // SQL_CONNECTION_H_