storage/nfs: optimize OpenFile()

src/input/plugins/NfsInputPlugin.cxx

@@ -31,6 +31,15 @@ public:
 				  NFS_MAX_BUFFERED,
 				  NFS_RESUME_AT) {}
 
+	NfsInputStream(NfsConnection &_connection, std::string_view _path,
+		       Mutex &_mutex) noexcept
+		:NfsFileReader(_connection, _path),
+		 AsyncInputStream(NfsFileReader::GetEventLoop(),
+				  NfsFileReader::GetAbsoluteUri(),
+				  _mutex,
+				  NFS_MAX_BUFFERED,
+				  NFS_RESUME_AT) {}
+
 	~NfsInputStream() override {
 		DeferClose();
 	}
@@ -225,3 +234,10 @@ const InputPlugin input_plugin_nfs = {
 	input_nfs_open,
 	nullptr
 };
+
+InputStreamPtr
+OpenNfsInputStream(NfsConnection &connection, std::string_view path,
+		   Mutex &mutex)
+{
+	return std::make_unique<NfsInputStream>(connection, path, mutex);
+}

src/input/plugins/NfsInputPlugin.hxx

@@ -1,9 +1,17 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 // Copyright The Music Player Daemon Project
 
-#ifndef MPD_INPUT_NFS_H
-#define MPD_INPUT_NFS_H
+#pragma once
+
+#include "input/Ptr.hxx"
+#include "thread/Mutex.hxx"
+
+#include <string_view>
+
+class NfsConnection;
 
 extern const struct InputPlugin input_plugin_nfs;
 
-#endif
+InputStreamPtr
+OpenNfsInputStream(NfsConnection &connection, std::string_view path,
+		   Mutex &mutex);

src/lib/nfs/FileReader.cxx

@@ -10,6 +10,8 @@
 
 #include <nfsc/libnfs.h> // for struct nfs_stat_64
 
+#include <fmt/core.h>
+
 #include <cassert>
 #include <cstring>
 #include <stdexcept>
@@ -18,16 +20,37 @@
 #include <fcntl.h>
 #include <sys/stat.h> // for S_ISREG()
 
+using std::string_view_literals::operator""sv;
+
 NfsFileReader::NfsFileReader() noexcept
 	:defer_open(nfs_get_event_loop(), BIND_THIS_METHOD(OnDeferredOpen))
 {
 }
 
+NfsFileReader::NfsFileReader(NfsConnection &_connection,
+			     std::string_view _path) noexcept
+	:state(State::DEFER),
+	 path(_path),
+	 connection(&_connection),
+	 defer_open(_connection.GetEventLoop(), BIND_THIS_METHOD(OnDeferredOpen))
+{
+	defer_open.Schedule();
+}
+
 NfsFileReader::~NfsFileReader() noexcept
 {
 	assert(state == State::INITIAL);
 }
 
+std::string
+NfsFileReader::GetAbsoluteUri() const noexcept
+{
+	return fmt::format("nfs://{}{}/{}"sv,
+			   connection != nullptr ? connection->GetServer() : server,
+			   connection != nullptr ? connection->GetExportName() : export_name,
+			   path);
+}
+
 void
 NfsFileReader::Close() noexcept
 {
@@ -293,12 +316,13 @@ NfsFileReader::OnDeferredOpen() noexcept
 {
 	assert(state == State::DEFER);
 
-	try {
-		connection = &nfs_get_connection(server, export_name);
-	} catch (...) {
-		OnNfsFileError(std::current_exception());
-		return;
-	}
+	if (connection == nullptr)
+		try {
+			connection = &nfs_get_connection(server, export_name);
+		} catch (...) {
+			OnNfsFileError(std::current_exception());
+			return;
+		}
 
 	connection->AddLease(*this);
 	state = State::MOUNT;

src/lib/nfs/FileReader.hxx

@@ -45,7 +45,7 @@ class NfsFileReader : NfsLease, NfsCallback {
 
 	std::string server, export_name, path;
 
-	NfsConnection *connection;
+	NfsConnection *connection = nullptr;
 
 	nfsfh *fh;
 
@@ -60,12 +60,17 @@ class NfsFileReader : NfsLease, NfsCallback {
 
 public:
 	NfsFileReader() noexcept;
+	explicit NfsFileReader(NfsConnection &_connection,
+			       std::string_view _path) noexcept;
 	~NfsFileReader() noexcept;
 
 	auto &GetEventLoop() const noexcept {
 		return defer_open.GetEventLoop();
 	}
 
+	[[nodiscard]] [[gnu::pure]]
+	std::string GetAbsoluteUri() const noexcept;
+
 	void Close() noexcept;
 	void DeferClose() noexcept;
 

src/storage/plugins/NfsStorage.cxx

@@ -12,6 +12,7 @@
 #include "lib/nfs/Connection.hxx"
 #include "lib/nfs/Glue.hxx"
 #include "input/InputStream.hxx"
+#include "input/plugins/NfsInputPlugin.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "thread/Mutex.hxx"
 #include "thread/Cond.hxx"
@@ -252,9 +253,9 @@ NfsStorage::MapToRelativeUTF8(std::string_view uri_utf8) const noexcept
 InputStreamPtr
 NfsStorage::OpenFile(std::string_view uri_utf8, Mutex &_mutex)
 {
-	// TODO create NfsInputStream directly
-	auto uri = MapUTF8(uri_utf8);
-	return InputStream::Open(uri.c_str(), _mutex);
+	WaitConnected();
+
+	return OpenNfsInputStream(*connection, uri_utf8, _mutex);
 }
 
 static void