statement wrappers have been deprecated

It’s a lot of fun removing old code; it’s less fun when removing that old code breaks lots of things.  That’s what happened when bug 589032 was checked in to mozilla-central last week. We had deprecated mozIStorageStatementWrapper over a year ago; bug 589032 removed mozIStorageStatementWrapper in favor of using mozIStorageStatement directly.

As there have been a couple reports of breakage (which likely means there’s a lot more breakage pending), and I have claimed in the bug that fixing said breakage is a straightforward process, here’s the quick-n-dirty guide to doing so. (Warning: may contain bugs or be incomplete. Please note any oversights in the comments.)

Code that created wrappers:

var wrapper = new Components.Constructor("@mozilla.org/storage/statement-wrapper;1",
                                         Ci.mozIStorageStatementWrapper,
                                         "initialize");
function createStatement(db, aSQL) {
  return new wrapper(db.createStatement(aSQL));
}

or perhaps:

var wrapper = Cc["@mozilla.org/storage/statement-wrapper;1"]
                .createInstance(Ci.mozIStorageStatementWrapper);
wrapper.initialize(statement);

should be replaced with:

function createStatement(db, aSQL) {
  return db.createStatement(aSQL);
}

Of course, that’s almost not worth having a separate function for. :)

Nearly all of the methods that you were calling on the wrapper remain unchanged, with the exception of:

foo = wrapped_stmt.execute();

That should be replaced with:

foo = stmt.executeStep();

Statements have an execute() method, but it does something slightly different than the wrapper’s execute() method.

Finally, where you finalize your statements (you are finalizing your statements, right?):

wrapped_stmt.statement.finalize();

is now simply:

statement.finalize();

As I said earlier, please note any omissions or errors in the comments!

3 comments

  1. If there’s a bug for this change, please be sure it has the dev-doc-needed keyword so we can ensure that it’s documented.

  2. Serge Gautherie

    Checking https://hg.mozilla.org/mozilla-central/rev/5371c239bbf6,
    it looks like execute() calls are unchanged,
    and executeStep() replaces step() rather.
    This needs to be clarified.