WIP.

upb/legacy_msg_reflection.c

@@ -211,15 +211,6 @@ bool upb_array_set(upb_array *arr, size_t i, upb_msgval val) {
 
 /** upb_map *******************************************************************/
 
-struct upb_map {
-  upb_fieldtype_t key_type;
-  upb_fieldtype_t val_type;
-  /* We may want to optimize this to use inttable where possible, for greater
-   * efficiency and lower memory footprint. */
-  upb_strtable strtab;
-  upb_arena *arena;
-};
-
 static void upb_map_tokey(upb_fieldtype_t type, upb_msgval *key,
                           const char **out_key, size_t *out_len) {
   switch (type) {

upb/legacy_msg_reflection.h

@@ -7,9 +7,6 @@
 
 #include "upb/port_def.inc"
 
-struct upb_map;
-typedef struct upb_map upb_map;
-
 struct upb_mapiter;
 typedef struct upb_mapiter upb_mapiter;
 

upb/msg.h

@@ -11,6 +11,8 @@
 
 #include <stdint.h>
 #include <string.h>
+
+#include "upb/table.int.h"
 #include "upb/upb.h"
 
 #ifdef __cplusplus
@@ -55,6 +57,19 @@ typedef struct {
   upb_arena *arena;
 } upb_array;
 
+/* Our internal representation for maps. */
+typedef struct {
+  /* First element must be upb_array so code like parser/serializer can treat
+   * map fields as array. */
+  upb_array array;
+
+  /* A side index whose values are indexes into the array. May be NULL. */
+  union {
+    upb_strtable *strtab;
+    upb_inttable *inttab;
+  } table;
+} upb_map;
+
 upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a);
 upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a);
 

upbc/generator.cc

@@ -368,8 +368,10 @@ void GenerateMessageInHeader(const protobuf::Descriptor* message, Output& output
         GetSizeInit(layout.GetOneofCaseOffset(oneof)));
   }
 
-  for (auto field : FieldNumberOrder(message)) {
+  // Generate const methods.
 
+  for (auto field : FieldNumberOrder(message)) {
+    // Generate hazzer (if any).
     if (layout.HasHasbit(field)) {
       output(
           "UPB_INLINE bool $0_has_$1(const $0 *msg) { "
@@ -384,6 +386,7 @@ void GenerateMessageInHeader(const protobuf::Descriptor* message, Output& output
           field->number());
     }
 
+    // Generate getter.
     if (field->is_repeated()) {
       output(
           "UPB_INLINE $0 const* $1_$2(const $1 *msg, size_t *len) { "
@@ -409,8 +412,15 @@ void GenerateMessageInHeader(const protobuf::Descriptor* message, Output& output
 
   output("\n");
 
+  // Generate mutable methods.
+
   for (auto field : FieldNumberOrder(message)) {
-    if (field->is_repeated()) {
+    if (message->options().map_entry() && field->name() == "key") {
+      // Emit nothing, map keys cannot be changed directly.  Users must use
+      // the mutators of the map itself.
+    } else if (field->is_map()) {
+      // TODO(haberman): add map-based mutators.
+    } else if (field->is_repeated()) {
       output(
           "UPB_INLINE $0* $1_mutable_$2($1 *msg, size_t *len) {\n"
           "  return ($0*)_upb_array_mutable_accessor(msg, $3, len);\n"
@@ -453,6 +463,7 @@ void GenerateMessageInHeader(const protobuf::Descriptor* message, Output& output
             UpbType(field));
       }
     } else {
+      // Non-repeated field.
       output("UPB_INLINE void $0_set_$1($0 *msg, $2 value) {\n", msgname,
              field->name(), CType(field));
       if (field->containing_oneof()) {