1 files changed, 170 insertions, 0 deletions
diff --git a/load.go b/load.go
new file mode 100644
index 0000000..1fbd2ca
--- /dev/null
+++ b/load.go
@@ -0,0 +1,170 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"google.golang.org/protobuf/encoding/protojson"
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/proto"
+)
+
+func LoadPB(pb proto.Message) error {
+	return ReLoad(pb)
+}
+
+// uses the version to die. This is needed because loading binary
+// protobuf files with rearranged messages is indeterminate
+func ReLoad(pb proto.Message) error {
+	fullname, err := GetFilename(pb)
+	if (fullname == "") || (err != nil) {
+		panic("config.LoadPB() got blank filename = ''")
+	}
+	// this code needs work
+	newver, pbver, err := VersionCheckFile(pb, fullname)
+	if errors.Is(err, os.ErrNotExist) {
+		//
+		err = SaveToFilename(pb, fullname)
+		return err
+	}
+	if errors.Is(err, VersionMismatch) || (newver != pbver) {
+		fmt.Println("")
+		fmt.Printf("VERSION new '%s' != cur PB '%s'\n", newver, pbver)
+		fmt.Println("")
+		fmt.Println("Your protobuf file is old and can not be loaded")
+		fmt.Println("your application must decide how to handle this (delete or fix)")
+		fmt.Println("always die here. application is broken")
+		fmt.Println("You must delete or convert the file", fullname)
+		fmt.Println("")
+		// probably should ALWAYS PANIC HERE
+		// upon further study, always die here is better than not
+		s := fmt.Sprintf("protobuf version wrong. delete or fix %s", fullname)
+		panic(s)
+	}
+	if err != nil {
+		// return to let the application figure this out
+		return err
+	}
+	return nil
+}
+
+func LoadFromFilename(pb proto.Message, fullname string) error {
+	if strings.HasSuffix(fullname, ".text") {
+		return loadTEXT(pb, fullname)
+	}
+	if strings.HasSuffix(fullname, ".json") {
+		return loadJSON(pb, fullname)
+	}
+	if strings.HasSuffix(fullname, ".pb") {
+		return loadPB(pb, fullname)
+	}
+
+	return fmt.Errorf("unknown filetype '%s'", fullname)
+}
+
+func loadPB(pb proto.Message, fullname string) error {
+	data, err := loadFile(fullname)
+	if err != nil {
+		// set pb.Filename that was attempted
+		return err
+	}
+
+	if err = proto.Unmarshal(data, pb); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func loadTEXT(pb proto.Message, fullname string) error {
+	var data []byte
+	var err error
+	SetFilename(pb, fullname)
+	if data, err = loadFile(fullname); err != nil {
+		return err
+	}
+
+	// don't even bother with Marshal()
+	if data == nil {
+		return ErrEmpty // file is empty
+	}
+
+	// Unmarshal()
+	if err = prototext.Unmarshal(data, pb); err != nil {
+		return ErrMarshal
+	}
+
+	if fn, err := GetFilename(pb); err != nil {
+		if fn != fullname {
+			SetFilename(pb, fullname)
+		}
+	}
+	return nil
+}
+
+// json files are backup Marshal() data in case .text Unmarshal() fails
+// they always should have the ".text" filename in them
+func loadJSON(pb proto.Message, fullname string) error {
+	var data []byte
+	var err error
+	if data, err = loadFile(fullname); err != nil {
+		return err
+	}
+
+	// don't even bother with Marshal()
+	if data == nil {
+		return ErrEmpty // file is empty
+	}
+
+	// Unmarshal()
+	if err = protojson.Unmarshal(data, pb); err != nil {
+		return ErrMarshal
+	}
+
+	if fn, err := GetFilename(pb); err != nil {
+		if fn != fullname {
+			SetFilename(pb, fullname)
+		}
+	}
+	return nil
+}
+
+func loadFile(fullname string) ([]byte, error) {
+	data, err := os.ReadFile(fullname)
+	if errors.Is(err, os.ErrNotExist) {
+		// if file does not exist, just return nil. this
+		return nil, err
+	}
+	if err != nil {
+		return nil, err
+	}
+	if len(data) == 0 {
+		return data, ErrEmpty
+	}
+	return data, nil
+}
+
+/* left this here to remind myself just how dumb I can be
+
+// dumb but simple to read logic
+func missingConfig(fullname string) error {
+	data1, err1 := os.ReadFile(fullname)
+	if !errors.Is(err1, os.ErrNotExist) {
+		return err1
+	}
+
+	data2, err2 := os.ReadFile(fullname + ".json")
+	if !errors.Is(err2, os.ErrNotExist) {
+		return err2
+	}
+	if errors.Is(err1, os.ErrNotExist) && errors.Is(err2, os.ErrNotExist) {
+		return os.ErrNotExist
+	}
+	if (len(data1) == 0) && (len(data2) == 0) {
+		return ErrEmpty
+	}
+	return nil
+}
+*/