From 759d095548e7135bbfeb68ac6b0a21857af49527 Mon Sep 17 00:00:00 2001
From: Laytan Laats <laytanlaats@hotmail.com>
Date: Sat, 23 Dec 2023 18:52:53 +0100
Subject: [PATCH] encoding/cbor: ignore struct fields with `cbor:"-"`

---
 core/encoding/cbor/marshal.odin              | 37 ++++++++++++++------
 core/encoding/cbor/unmarshal.odin            |  4 +++
 tests/core/encoding/cbor/test_core_cbor.odin |  3 ++
 3 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/core/encoding/cbor/marshal.odin b/core/encoding/cbor/marshal.odin
index 898371adf..deb7ba020 100644
--- a/core/encoding/cbor/marshal.odin
+++ b/core/encoding/cbor/marshal.odin
@@ -422,7 +422,13 @@ marshal_into_encoder :: proc(e: Encoder, v: any) -> (err: Marshal_Error) {
 		case Tag: return err_conv(_encode_tag(e, vv))
 		}
 
-		err_conv(_encode_u16(e, u16(len(info.names)), .Map)) or_return
+		field_name :: #force_inline proc(info: runtime.Type_Info_Struct, i: int) -> string {
+			if cbor_name := string(reflect.struct_tag_get(reflect.Struct_Tag(info.tags[i]), "cbor")); cbor_name != "" {
+				return cbor_name
+			} else {
+				return info.names[i]
+			}
+		}
 
 		marshal_entry :: #force_inline proc(e: Encoder, info: runtime.Type_Info_Struct, v: any, name: string, i: int) -> Marshal_Error {
 			err_conv(_encode_text(e, name)) or_return
@@ -448,13 +454,14 @@ marshal_into_encoder :: proc(e: Encoder, v: any) -> (err: Marshal_Error) {
 
 			return marshal_into(e, field_any)
 		}
-
-		field_name :: #force_inline proc(info: runtime.Type_Info_Struct, i: int) -> string {
-			if cbor_name := string(reflect.struct_tag_get(reflect.Struct_Tag(info.tags[i]), "cbor")); cbor_name != "" {
-				return cbor_name
-			} else {
-				return info.names[i]
+		
+		n: u64; {
+			for _, i in info.names {
+				if field_name(info, i) != "-" {
+					n += 1
+				}
 			}
+			err_conv(_encode_u64(e, n, .Map)) or_return
 		}
 
 		if .Deterministic_Map_Sorting in e.flags {
@@ -462,11 +469,16 @@ marshal_into_encoder :: proc(e: Encoder, v: any) -> (err: Marshal_Error) {
 				name:  string,
 				field: int,
 			}
-			entries := make([dynamic]Name, 0, len(info.names), context.temp_allocator) or_return
+			entries := make([dynamic]Name, 0, n, context.temp_allocator) or_return
 			defer delete(entries)
 
 			for name, i in info.names {
-				append(&entries, Name{field_name(info, i), i}) or_return
+				fname := field_name(info, i)
+				if fname == "-" {
+					continue
+				}
+
+				append(&entries, Name{fname, i}) or_return
 			}
 
 			// Sort lexicographic on the bytes of the key.
@@ -479,7 +491,12 @@ marshal_into_encoder :: proc(e: Encoder, v: any) -> (err: Marshal_Error) {
 			}
 		} else {
 			for name, i in info.names {
-				marshal_entry(e, info, v, field_name(info, i), i) or_return
+				fname := field_name(info, i)
+				if fname == "-" {
+					continue
+				}
+
+				marshal_entry(e, info, v, fname, i) or_return
 			}
 		}
 		return
diff --git a/core/encoding/cbor/unmarshal.odin b/core/encoding/cbor/unmarshal.odin
index ae7f97c98..9ad25a38d 100644
--- a/core/encoding/cbor/unmarshal.odin
+++ b/core/encoding/cbor/unmarshal.odin
@@ -650,6 +650,10 @@ _unmarshal_map :: proc(d: Decoder, v: any, ti: ^reflect.Type_Info, hdr: Header,
 			{
 				for field, field_idx in fields {
 					tag_value := string(reflect.struct_tag_get(field.tag, "cbor"))
+					if tag_value == "-" {
+						continue
+					}
+
 					if key == tag_value {
 						use_field_idx = field_idx
 						break
diff --git a/tests/core/encoding/cbor/test_core_cbor.odin b/tests/core/encoding/cbor/test_core_cbor.odin
index 0fb8b521f..daf31c277 100644
--- a/tests/core/encoding/cbor/test_core_cbor.odin
+++ b/tests/core/encoding/cbor/test_core_cbor.odin
@@ -130,6 +130,7 @@ Foo :: struct {
 	small_onetwenty: i128,
 	biggest: big.Int,
 	smallest: big.Int,
+	ignore_this: ^Foo `cbor:"-"`,
 }
 
 FooBar :: enum {
@@ -189,6 +190,7 @@ test_marshalling :: proc(t: ^testing.T) {
 			smallie = cbor.Negative_U64(max(u64)),
 			onetwenty = i128(12345),
 			small_onetwenty = -i128(max(u64)),
+			ignore_this = &Foo{},
 		}
 
 		big.atoi(&f.biggest, "1234567891011121314151617181920")
@@ -343,6 +345,7 @@ test_marshalling :: proc(t: ^testing.T) {
 		ev(t, backf.smallie, f.smallie)
 		ev(t, backf.onetwenty, f.onetwenty)
 		ev(t, backf.small_onetwenty, f.small_onetwenty)
+		ev(t, backf.ignore_this, nil)
 		
 		s_equals, s_err := big.equals(&backf.smallest, &f.smallest)
 		ev(t, s_err, nil)