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// Copyright 2021 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.
#ifndef LIB_DEVICE_WATCHER_CPP_DEVICE_WATCHER_H_
#define LIB_DEVICE_WATCHER_CPP_DEVICE_WATCHER_H_
#include <lib/zx/channel.h>
#include <lib/zx/status.h>
#include <memory>
#include <string_view>
#include <fbl/unique_fd.h>
namespace device_watcher {
// Waits for |file| to appear in |dir|, and opens it when it does.
zx_status_t WaitForFile(const fbl::unique_fd& dir, const char* file, fbl::unique_fd* out);
// Waits for a device with topological path |topo_path| to appear in |dir| then opens it.
// This works by opening each files in |dir| as fuchsia.device.Controller and calling
// GetTopologicalPath.
zx::status<zx::channel> WaitForDeviceTopologicalPath(const fbl::unique_fd& dir,
std::string_view topo_path);
// Waits for the relative |path| starting in |dir| to appear, and opens it.
zx_status_t RecursiveWaitForFile(const fbl::unique_fd& dir, const char* path, fbl::unique_fd* out);
// Waits for the absolute |path| to appear, and opens it.
// NOTE: This only works for paths starting with /dev/,
// otherwise it will return ZX_ERR_NOT_SUPPORTED.
zx_status_t RecursiveWaitForFile(const char* path, fbl::unique_fd* out);
// Waits for the relative |path| starting in |dir| to appear, and opens it in Read only mode.
zx_status_t RecursiveWaitForFileReadOnly(const fbl::unique_fd& dir, const char* path,
fbl::unique_fd* out);
// Waits for the absolute |path| to appear, and opens it as ReadOnly.
// NOTE: This only works for paths starting with /dev/,
// otherwise it will return ZX_ERR_NOT_SUPPORTED.
zx_status_t RecursiveWaitForFileReadOnly(const char* path, fbl::unique_fd* out);
// DirWatcher can be used to detect when a file has been removed from the filesystem.
//
// Example usage:
//
// std::unique_ptr<DirWatcher> watcher;
// zx_status_t status = DirWatcher::Create(dir_fd, &watcher);
// ...
// // Trigger removal of file here.
// ...
// status = watcher->WaitForRemoval(filename, deadline);
class DirWatcher {
public:
// |dir_fd| is the directory to watch.
static zx_status_t Create(fbl::unique_fd dir_fd, std::unique_ptr<DirWatcher>* out_dir_watcher);
// Users should call Create instead. This is public for make_unique.
// TODO(https://fxbug.dev/89042): this should be a `fidl::ClientEnd<fuchsia_io::DirectoryWatcher>`
// once LLCPP is in the SDK.
explicit DirWatcher(zx::channel client) : client_(std::move(client)) {}
// Returns ZX_OK if |filename| is removed from the directory before the given timeout elapses.
// If no filename is specified, this will wait for any file in the directory to be removed.
zx_status_t WaitForRemoval(std::string_view filename, zx::duration timeout);
private:
zx::channel client_;
};
} // namespace device_watcher
#endif // LIB_DEVICE_WATCHER_CPP_DEVICE_WATCHER_H_