zircon/system/ulib/fs/include/fs/tracked-remote-dir.h

// 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.

#pragma once

#include <fbl/macros.h>
#include <fbl/string.h>
#include <fs/pseudo-dir.h>
#include <fs/remote-dir.h>
#include <lib/async/cpp/wait.h>

#include "pseudo-dir.h"
#include "vnode.h"

namespace fs {

// A remote directory which automatically removes itself once the remote channel
// being tracked is closed.
//
// This class is thread-compatible.
class TrackedRemoteDir : public RemoteDir {
public:
    // Create a directory which is accessed remotely through |remote|.
    TrackedRemoteDir(zx::channel remote);

    // Adds |this| as an entry to |container| with the label |name|.
    //
    // Begins monitoring |remote| (provided at construction-time) for |PEER_CLOSED|.
    // When this signal is activated, the |name| entry is removed from |container|.
    //
    // Returns |ZX_ERR_BAD_STATE| if this directory is already tracked.
    // Returns an error if an entry named |name| cannot be added to |container|.
    // Returns an error if the underlying handle cannot be monitored for peer closed.
    zx_status_t AddAsTrackedEntry(async_dispatcher_t* dispatcher,
                                  PseudoDir* container, fbl::String name);

private:
    void HandleClose(async_dispatcher_t* dispatcher, async::WaitBase* wait,
                     zx_status_t status, const zx_packet_signal_t* signal);
    bool IsTracked() const;

    async::WaitMethod<TrackedRemoteDir, &TrackedRemoteDir::HandleClose> tracker_;
    fbl::String name_;
    PseudoDir* container_;
};

} // namespace fs