blob: f2a82385826bade5176a0ec6d6cb93f0c1f15006 [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 <trace/event.h>
#include "src/ledger/bin/app/page_usage_listener.h"
#include "src/ledger/bin/app/types.h"
#include "src/ledger/bin/storage/public/types.h"
#include "src/lib/fxl/memory/weak_ptr.h"
namespace ledger {
// A notifier for |PageUsageListener|.
// Given information about when internal and external page connections open and
// close, |PageConnectionNotifier| calls the corresponding methods from
// |PageUsageListener|. The |PageUsageListener| given in the constructor should
// outlive this object.
class PageConnectionNotifier {
PageConnectionNotifier(std::string ledger_name, storage::PageId page_id,
PageUsageListener* page_usage_listener);
// Registers a new external page request.
void RegisterExternalRequest();
// Unregisters all active external page requests. This can be because all
// active connections were closed, or because of failure to bind the requests.
void UnregisterExternalRequests();
// Registers a new internal page request, and returns a token. The internal
// request is unregistered when the token is destructed.
ExpiringToken NewInternalRequestToken();
// Sets the on_empty callback, to be called every time this object becomes
// empty.
void set_on_empty(fit::closure on_empty_callback);
// Checks and returns whether there are no active external or internal
// requests.
bool IsEmpty();
// Checks whether this object is empty, and if it is and the on_empty callback
// is set, calls it.
void CheckEmpty();
const std::string ledger_name_;
const storage::PageId page_id_;
PageUsageListener* page_usage_listener_;
// Stores whether the page was opened by an external request but did not yet
// send a corresponding OnPageUnused. The OnPageUnused notification is sent as
// soon as all internal and external requests to the page are done.
bool must_notify_on_page_unused_ = false;
// Stores whether the page is currently opened by an external request.
bool has_external_requests_ = false;
// Stores the number of active internal requests.
ssize_t internal_request_count_ = 0;
fit::closure on_empty_callback_;
// Must be the last member.
fxl::WeakPtrFactory<PageConnectionNotifier> weak_factory_;
} // namespace ledger