initial commit

1 files changed, 87 insertions, 0 deletions

diff --git a/server/data.go b/server/data.go
new file mode 100644
index 0000000..b7ed280
--- /dev/null
+++ b/server/data.go
@@ -0,0 +1,87 @@
+package server
+
+import (
+	"os"
+	"encoding/binary"
+	"git.citrons.xyz/metronode/phony"
+)
+
+var dataManager struct {
+	phony.Inbox
+	errHand interface {
+		OnSaveError(from phony.Actor, err error)
+		OnLoadError(from phony.Actor, err error)
+	}
+}
+
+type atomicWriter struct {
+	from phony.Actor
+	name string
+	tmpFile *os.File
+}
+
+func createAtomic(from phony.Actor, name string) (atomicWriter, error) {
+	os.Mkdir("world", 0777)
+	f, err := os.CreateTemp("world", "*.tmp")
+	if err != nil {
+		dataManager.errHand.OnSaveError(from, err)
+		return atomicWriter {}, err
+	}
+	return atomicWriter {from, name, f}, nil
+}
+
+func (f atomicWriter) Write(b []byte) (n int, err error) {
+	return f.tmpFile.Write(b)
+}
+
+func (f atomicWriter) Close() error {
+	if f.tmpFile == nil {
+		return nil
+	}
+	dataManager.Act(f.from, func() {
+		err := f.tmpFile.Close()
+		if err != nil {
+			dataManager.errHand.OnSaveError(&dataManager, err)
+			return
+		}
+		err = os.Rename(f.tmpFile.Name(), f.name)
+		if err != nil {
+			dataManager.errHand.OnSaveError(&dataManager, err)
+		}
+	})
+	return nil
+}
+
+func saveDataFile[T any](from phony.Actor, name string, data T) {
+	f, err := createAtomic(from, "world/" + name + ".bin")
+	if err != nil {
+		dataManager.errHand.OnSaveError(from, err)
+		return
+	}
+	defer f.Close()
+	err = binary.Write(f, binary.BigEndian, data)
+	if err != nil {
+		dataManager.errHand.OnSaveError(from, err)
+	}
+}
+
+func loadDataFile[T any](
+		from phony.Actor, name string, reply func(data T, ok bool)) {
+	dataManager.Act(from, func() {
+		f, err := os.Open("world/" + name + ".bin")
+		if err != nil {
+			if !os.IsNotExist(err) {
+				dataManager.errHand.OnLoadError(&dataManager, err)
+			}
+			return
+		}
+		defer f.Close()
+		var data T
+		err = binary.Read(f, binary.BigEndian, &data)
+		if err != nil {
+			dataManager.errHand.OnLoadError(&dataManager, err)
+		}
+		from.Act(nil, func() {reply(data, err == nil)})
+	})
+}
+