From c3d6c3b553a2b1ca474f6726b36d8adec9744a3e Mon Sep 17 00:00:00 2001
From: saji <champ189@umn.edu>
Date: Fri, 30 Jun 2023 07:18:15 -0500
Subject: [PATCH] use custom error and panic on invariant violation

---
 skylab/skylab.go                | 12 ++++++------
 skylab/skylab_gen.go            | 11 +++++------
 skylab/templates/golang.go.tmpl |  9 ++++-----
 3 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/skylab/skylab.go b/skylab/skylab.go
index 41e457b..a76b4ea 100644
--- a/skylab/skylab.go
+++ b/skylab/skylab.go
@@ -41,11 +41,11 @@ func float32FromBytes(b []byte, bigEndian bool) (f float32) {
 
 // Packet is any Skylab-generated packet.
 type Packet interface {
-	MarshalPacket() ([]byte, error)
-	UnmarshalPacket(p []byte) error
-	CANId() (uint32, error)
-	Size() uint
-	String() string
+	Marshaler
+	Unmarshaler
+	Ider
+	Sizer
+	fmt.Stringer // to get the name
 }
 
 // Marshaler is a packet that can be marshalled into bytes.
@@ -164,7 +164,7 @@ func (e *BusEvent) UnmarshalMsg(b []byte) ([]byte, error) {
 // generator since we can use the switch/case thing since it's the fastest
 
 type UnknownIdError struct {
-	id uint64
+	id uint32
 }
 
 func (e *UnknownIdError) Error() string {
diff --git a/skylab/skylab_gen.go b/skylab/skylab_gen.go
index 9b5fb12..894d990 100644
--- a/skylab/skylab_gen.go
+++ b/skylab/skylab_gen.go
@@ -1,9 +1,8 @@
-// generated by gen_skylab.go at 2023-06-28 08:15:54.687487803 -0500 CDT m=+0.002619032 DO NOT EDIT!
+// generated by gen_skylab.go at 2023-06-30 07:17:44.496220436 -0500 CDT m=+0.002737106 DO NOT EDIT!
 
 package skylab
 
 import (
-	"errors"
 	"encoding/binary"
 	"encoding/json"
 )
@@ -236,7 +235,7 @@ var idMap = map[uint32]bool{
 // If the CAN ID is unknown, it will return an error.
 func FromCanFrame(id uint32, data []byte) (Packet, error) {
 	if !idMap[id] {
-		return nil, &UnknownIdError{ uint64(id) }
+		return nil, &UnknownIdError{ id }
 	}
 	switch id {
 	case 0x10:
@@ -576,13 +575,13 @@ func FromCanFrame(id uint32, data []byte) (Packet, error) {
 		return res, nil
 	}
 
-	return nil, errors.New("failed to match Id, something is really wrong")
+	panic("This should never happen. CAN ID didn't match but was in ID map")
 }
 
 
 func FromJson (id uint32, raw []byte) (Packet, error) {
 	if !idMap[id] {
-		return nil, errors.New("unknown id")
+		return nil, &UnknownIdError{ id }
 	}
 	switch id {
 	case 0x10:
@@ -922,7 +921,7 @@ func FromJson (id uint32, raw []byte) (Packet, error) {
 		return res, err
 	}
 
-	return nil, errors.New("failed to match id")
+	panic("This should never happen. CAN ID didn't match but was in ID map")
 }
 
 
diff --git a/skylab/templates/golang.go.tmpl b/skylab/templates/golang.go.tmpl
index 5f781c9..5254aa1 100644
--- a/skylab/templates/golang.go.tmpl
+++ b/skylab/templates/golang.go.tmpl
@@ -84,7 +84,6 @@ func (p *{{$structName}}) String() string {
 package skylab
 
 import (
-	"errors"
 	"encoding/binary"
 	"encoding/json"
 )
@@ -114,7 +113,7 @@ var idMap = map[uint32]bool{
 // If the CAN ID is unknown, it will return an error.
 func FromCanFrame(id uint32, data []byte) (Packet, error) {
 	if !idMap[id] {
-		return nil, &UnknownIdError{ uint64(id) }
+		return nil, &UnknownIdError{ id }
 	}
 	switch id {
 {{- range $p := .Packets }}
@@ -133,13 +132,13 @@ func FromCanFrame(id uint32, data []byte) (Packet, error) {
 {{- end}}
 	}
 
-	return nil, errors.New("failed to match Id, something is really wrong")
+	panic("This should never happen. CAN ID didn't match but was in ID map")
 }
 
 
 func FromJson (id uint32, raw []byte) (Packet, error) {
 	if !idMap[id] {
-		return nil, errors.New("unknown id")
+		return nil, &UnknownIdError{ id }
 	}
 	switch id {
 {{- range $p := .Packets }}
@@ -158,7 +157,7 @@ func FromJson (id uint32, raw []byte) (Packet, error) {
 {{- end }}
 	}
 
-	return nil, errors.New("failed to match id")
+	panic("This should never happen. CAN ID didn't match but was in ID map")
 }
 
 {{range .Packets -}}