DetachedSong, db/LightSong, db/simple/Song: use std::chrono::system_clock::time_point

src/db/LightSong.hxx

@@ -24,8 +24,7 @@
 #include "Compiler.h"
 
 #include <string>
-
-#include <time.h>
+#include <chrono>
 
 struct Tag;
 
@@ -62,7 +61,11 @@ struct LightSong {
 	 */
 	const Tag *tag;
 
-	time_t mtime;
+	/**
+	 * The time stamp of the last file modification.  A negative
+	 * value means that this is unknown/unavailable.
+	 */
+	std::chrono::system_clock::time_point mtime;
 
 	/**
 	 * Start of this sub-song within the file.

src/db/plugins/ProxyDatabasePlugin.cxx

@@ -197,7 +197,11 @@ ProxySong::ProxySong(const mpd_song *song)
 	uri = mpd_song_get_uri(song);
 	real_uri = nullptr;
 	tag = &tag2;
-	mtime = mpd_song_get_last_modified(song);
+
+	const auto _mtime = mpd_song_get_last_modified(song);
+	mtime = _mtime > 0
+		? std::chrono::system_clock::from_time_t(_mtime)
+		: std::chrono::system_clock::time_point::min();
 
 #if LIBMPDCLIENT_CHECK_VERSION(2,3,0)
 	start_time = SongTime::FromS(mpd_song_get_start(song));

src/db/plugins/simple/Song.cxx

@@ -29,7 +29,7 @@
 #include <string.h>
 
 inline Song::Song(const char *_uri, size_t uri_length, Directory &_parent)
-	:parent(&_parent), mtime(0),
+	:parent(&_parent), mtime(std::chrono::system_clock::time_point::min()),
 	 start_time(SongTime::zero()), end_time(SongTime::zero())
 {
 	memcpy(uri, _uri, uri_length + 1);

src/db/plugins/simple/Song.hxx

@@ -70,7 +70,11 @@ struct Song {
 	 */
 	Directory *const parent;
 
-	time_t mtime;
+	/**
+	 * The time stamp of the last file modification.  A negative
+	 * value means that this is unknown/unavailable.
+	 */
+	std::chrono::system_clock::time_point mtime;
 
 	/**
 	 * Start of this sub-song within the file.

src/db/plugins/upnp/UpnpDatabasePlugin.cxx

@@ -63,7 +63,7 @@ public:
 		uri = uri2.c_str();
 		real_uri = real_uri2.c_str();
 		tag = &tag2;
-		mtime = 0;
+		mtime = std::chrono::system_clock::time_point::min();
 		start_time = end_time = SongTime::zero();
 	}
 };
@@ -314,7 +314,7 @@ visitSong(const UPnPDirObject &meta, const char *path,
 	song.uri = path;
 	song.real_uri = meta.url.c_str();
 	song.tag = &meta.tag;
-	song.mtime = 0;
+	song.mtime = std::chrono::system_clock::time_point::min();
 	song.start_time = song.end_time = SongTime::zero();
 
 	if (selection.Match(song))

src/db/update/Container.cxx

@@ -107,7 +107,7 @@ UpdateWalk::UpdateContainerFile(Directory &directory,
 						   *contdir);
 
 			// shouldn't be necessary but it's there..
-			song->mtime = std::chrono::system_clock::to_time_t(info.mtime);
+			song->mtime = info.mtime;
 
 			FormatDefault(update_domain, "added %s/%s",
 				      contdir->GetPath(), song->uri);

src/db/update/UpdateSong.cxx

@@ -51,9 +51,7 @@ UpdateWalk::UpdateSongFile2(Directory &directory,
 		return;
 	}
 
-	if (!(song != nullptr &&
-	      std::chrono::system_clock::to_time_t(info.mtime) == song->mtime &&
-	      !walk_discard) &&
+	if (!(song != nullptr && info.mtime == song->mtime && !walk_discard) &&
 	    UpdateContainerFile(directory, name, suffix, info)) {
 		if (song != nullptr)
 			editor.LockDeleteSong(directory, song);
@@ -80,7 +78,7 @@ UpdateWalk::UpdateSongFile2(Directory &directory,
 		modified = true;
 		FormatDefault(update_domain, "added %s/%s",
 			      directory.GetPath(), name);
-	} else if (std::chrono::system_clock::to_time_t(info.mtime) != song->mtime || walk_discard) {
+	} else if (info.mtime != song->mtime || walk_discard) {
 		FormatDefault(update_domain, "updating %s/%s",
 			      directory.GetPath(), name);
 		if (!song->UpdateFile(storage)) {