services/preferences/tracked/interceptable_pref_filter.cc

// Copyright 2014 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 "services/preferences/tracked/interceptable_pref_filter.h"

#include <utility>

#include "base/bind.h"
#include "base/callback_helpers.h"

InterceptablePrefFilter::InterceptablePrefFilter() {}
InterceptablePrefFilter::~InterceptablePrefFilter() {}

void InterceptablePrefFilter::FilterOnLoad(
    const PostFilterOnLoadCallback& post_filter_on_load_callback,
    std::unique_ptr<base::DictionaryValue> pref_store_contents) {
  if (filter_on_load_interceptor_.is_null()) {
    FinalizeFilterOnLoad(post_filter_on_load_callback,
                         std::move(pref_store_contents), false);
  } else {
    // Note, in practice (in the implementation as it was in May 2014) it would
    // be okay to pass an unretained |this| pointer below, but in order to avoid
    // having to augment the API everywhere to explicitly enforce the ownership
    // model as it happens to currently be: make the relationship simpler by
    // weakly binding the FinalizeFilterOnLoadCallback below to |this|.
    const FinalizeFilterOnLoadCallback finalize_filter_on_load(
        base::Bind(&InterceptablePrefFilter::FinalizeFilterOnLoad, AsWeakPtr(),
                   post_filter_on_load_callback));
    base::ResetAndReturn(&filter_on_load_interceptor_)
        .Run(finalize_filter_on_load, std::move(pref_store_contents));
  }
}

void InterceptablePrefFilter::InterceptNextFilterOnLoad(
    const FilterOnLoadInterceptor& filter_on_load_interceptor) {
  DCHECK(filter_on_load_interceptor_.is_null());
  filter_on_load_interceptor_ = filter_on_load_interceptor;
}