blob: 2b7b3a12cac5f97896e8f6b076acb92159875713 [file] [log] [blame]
// Copyright 2019 The Fuchsia 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 <lib/fit/function.h>
#include <map>
#include <vector>
#include "peridot/lib/convert/convert.h"
#include "src/ledger/bin/storage/public/types.h"
namespace ledger {
// Stores whether a given page is busy or available. After |MarkPageBusy| has
// been called, all calls to |OnPageAvailable| will be delayed until a call to
// |MarkPageAvailable|. By default, all pages are available.
class PageAvailabilityManager {
// Marks the page as busy and delays calling the callback in
// |OnPageAvailable| for this page. It is an error to call this method for a
// page that is already busy.
void MarkPageBusy(convert::ExtendedStringView page_id);
// Marks the page as available and calls any pending callbacks from
// |OnPageAvailable| for this page.
void MarkPageAvailable(convert::ExtendedStringView page_id);
// If the page is available calls the given callback directly. Otherwise,
// the callback is registered util the page becomes available.
void OnPageAvailable(convert::ExtendedStringView page_id,
fit::closure on_page_available);
// Checks whether there are no busy pages.
bool IsEmpty();
void set_on_empty(fit::closure on_empty_callback);
// Checks if the object is empty; if it is empty and on_empty callback_ is
// set, calls on_empty_callback_.
void CheckEmpty();
// For each busy page, stores the list of pending callbacks.
std::map<storage::PageId, std::vector<fit::closure>> busy_pages_;
fit::closure on_empty_callback_;
} // namespace ledger