db/Interface: GetUpdateStamp() returns std::chrono::system_clock::time_point

src/Stats.cxx

@@ -28,6 +28,7 @@
 #include "db/Stats.hxx"
 #include "system/Clock.hxx"
 #include "Log.hxx"
+#include "util/ChronoUtil.hxx"
 
 #include <chrono>
 
@@ -101,10 +102,10 @@ db_stats_print(Response &r, const Database &db)
 		 stats.song_count,
 		 total_duration_s);
 
-	const time_t update_stamp = db.GetUpdateStamp();
-	if (update_stamp > 0)
+	const auto update_stamp = db.GetUpdateStamp();
+	if (!IsNegative(update_stamp))
 		r.Format("db_update: %lu\n",
-			 (unsigned long)update_stamp);
+			 (unsigned long)std::chrono::system_clock::to_time_t(update_stamp));
 }
 
 #endif

src/db/Interface.hxx

@@ -24,7 +24,7 @@
 #include "tag/Type.h"
 #include "Compiler.h"
 
-#include <time.h>
+#include <chrono>
 
 struct DatabasePlugin;
 struct DatabaseStats;
@@ -129,10 +129,10 @@ public:
 
 	/**
 	 * Returns the time stamp of the last database update.
-	 * Returns 0 if that is not not known/available.
+	 * Returns a negative value if that is not not known/available.
 	 */
 	gcc_pure
-	virtual time_t GetUpdateStamp() const = 0;
+	virtual std::chrono::system_clock::time_point GetUpdateStamp() const = 0;
 };
 
 #endif

src/db/plugins/ProxyDatabasePlugin.cxx

@@ -89,7 +89,7 @@ class ProxyDatabase final : public Database, SocketMonitor, IdleMonitor {
 	struct mpd_connection *connection;
 
 	/* this is mutable because GetStats() must be "const" */
-	mutable time_t update_stamp;
+	mutable std::chrono::system_clock::time_point update_stamp;
 
 	/**
 	 * The libmpdclient idle mask that was removed from the other
@@ -128,7 +128,7 @@ public:
 
 	unsigned Update(const char *uri_utf8, bool discard) override;
 
-	time_t GetUpdateStamp() const override {
+	std::chrono::system_clock::time_point GetUpdateStamp() const override {
 		return update_stamp;
 	}
 
@@ -347,7 +347,7 @@ ProxyDatabase::Create(EventLoop &loop, DatabaseListener &listener,
 void
 ProxyDatabase::Open()
 {
-	update_stamp = 0;
+	update_stamp = std::chrono::system_clock::time_point::min();
 
 	try {
 		Connect();
@@ -818,7 +818,7 @@ ProxyDatabase::GetStats(const DatabaseSelection &selection) const
 	if (stats2 == nullptr)
 		ThrowError(connection);
 
-	update_stamp = (time_t)mpd_stats_get_db_update_time(stats2);
+	update_stamp = std::chrono::system_clock::from_time_t(mpd_stats_get_db_update_time(stats2));
 
 	DatabaseStats stats;
 	stats.song_count = mpd_stats_get_number_of_songs(stats2);

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -157,7 +157,7 @@ SimpleDatabase::Load()
 
 	FileInfo fi;
 	if (GetFileInfo(path, fi))
-		mtime = std::chrono::system_clock::to_time_t(fi.GetModificationTime());
+		mtime = fi.GetModificationTime();
 }
 
 void
@@ -166,7 +166,7 @@ SimpleDatabase::Open()
 	assert(prefixed_light_song == nullptr);
 
 	root = Directory::NewRoot();
-	mtime = 0;
+	mtime = std::chrono::system_clock::time_point::min();
 
 #ifndef NDEBUG
 	borrowed_song_count = 0;
@@ -358,7 +358,7 @@ SimpleDatabase::Save()
 
 	FileInfo fi;
 	if (GetFileInfo(path, fi))
-		mtime = std::chrono::system_clock::to_time_t(fi.GetModificationTime());
+		mtime = fi.GetModificationTime();
 }
 
 void

src/db/plugins/simple/SimpleDatabasePlugin.hxx

@@ -50,7 +50,7 @@ class SimpleDatabase : public Database {
 
 	Directory *root;
 
-	time_t mtime;
+	std::chrono::system_clock::time_point mtime;
 
 	/**
 	 * A buffer for GetSong() when prefixing the #LightSong
@@ -88,7 +88,7 @@ public:
 	 * Returns true if there is a valid database file on the disk.
 	 */
 	bool FileExists() const {
-		return mtime > 0;
+		return mtime >= std::chrono::system_clock::time_point(std::chrono::system_clock::duration::zero());
 	}
 
 	/**
@@ -125,7 +125,7 @@ public:
 
 	DatabaseStats GetStats(const DatabaseSelection &selection) const override;
 
-	time_t GetUpdateStamp() const override {
+	std::chrono::system_clock::time_point GetUpdateStamp() const override {
 		return mtime;
 	}
 

src/db/plugins/upnp/UpnpDatabasePlugin.cxx

@@ -94,8 +94,8 @@ public:
 
 	DatabaseStats GetStats(const DatabaseSelection &selection) const override;
 
-	time_t GetUpdateStamp() const override {
-		return 0;
+	std::chrono::system_clock::time_point GetUpdateStamp() const override {
+		return std::chrono::system_clock::time_point::min();
 	}
 
 private: