[textformat]: added missing newline when a message opens. (#245)

* [textformat]: added missing newline when a message opens.

* Added tostring() support to Lua that prints to text format.

Also fixed a gnarly bug that this exposed.

BUILD

@@ -656,6 +656,7 @@ cc_library(
     ],
     deps = [
         ":reflection",
+        ":textformat",
         ":upb",
         "@lua//:liblua",
     ],

tests/bindings/lua/test_upb.lua

@@ -458,6 +458,11 @@ function test_foo()
   assert_error_match("lupb.array expected", function () set.file = 1 end)
 
   set = upb.decode(FileDescriptorSet, descriptor)
+
+  -- Test that we can at least call this without crashing.
+  set_textformat = tostring(set)
+
+  -- print(set_textformat)
   assert_equal(#set.file, 1)
   assert_equal(set.file[1].name, "google/protobuf/descriptor.proto")
 end

upb/bindings/lua/msg.c

@@ -13,6 +13,7 @@
 #include "lauxlib.h"
 #include "upb/bindings/lua/upb.h"
 #include "upb/reflection.h"
+#include "upb/textencode.h"
 
 #include "upb/port_def.inc"
 
@@ -887,9 +888,41 @@ static int lupb_msg_newindex(lua_State *L) {
   return 1;
 }
 
+/**
+ * lupb_msg_tostring()
+ *
+ * Handles:
+ *   tostring(msg)
+ *   print(msg)
+ *   etc.
+ */
+static int lupb_msg_tostring(lua_State *L) {
+  upb_msg *msg = lupb_msg_check(L, 1);
+  const upb_msgdef *m;
+  char buf[1024];
+  size_t size;
+
+  lua_getiuservalue(L, 1, LUPB_MSGDEF_INDEX);
+  m = lupb_msgdef_check(L, -1);
+
+  size = upb_textencode(msg, m, NULL, 0, buf, sizeof(buf));
+
+  if (size < sizeof(buf)) {
+    lua_pushlstring(L, buf, size);
+  } else {
+    char *ptr = malloc(size + 1);
+    upb_textencode(msg, m, NULL, 0, ptr, size + 1);
+    lua_pushlstring(L, ptr, size);
+    free(ptr);
+  }
+
+  return 1;
+}
+
 static const struct luaL_Reg lupb_msg_mm[] = {
   {"__index", lupb_msg_index},
   {"__newindex", lupb_msg_newindex},
+  {"__tostring", lupb_msg_tostring},
   {NULL, NULL}
 };
 

upb/reflection.c

@@ -82,7 +82,7 @@ bool upb_msg_has(const upb_msg *msg, const upb_fielddef *f) {
     return *oneofcase(msg, field) == field->number;
   } else if (field->presence > 0) {
     uint32_t hasbit = field->presence;
-    return *PTR_AT(msg, hasbit / 8, char) | (1 << (hasbit % 8));
+    return *PTR_AT(msg, hasbit / 8, char) & (1 << (hasbit % 8));
   } else {
     UPB_ASSERT(field->descriptortype == UPB_DESCRIPTOR_TYPE_MESSAGE ||
                field->descriptortype == UPB_DESCRIPTOR_TYPE_GROUP);

upb/textencode.c

@@ -21,8 +21,6 @@ typedef struct {
 
 static void txtenc_msg(txtenc *e, const upb_msg *msg, const upb_msgdef *m);
 
-#define CHK(x) do { if (!(x)) { return false; } } while(0)
-
 static void txtenc_putbytes(txtenc *e, const void *data, size_t len) {
   size_t have = e->end - e->ptr;
   if (UPB_LIKELY(have >= len)) {
@@ -159,6 +157,7 @@ static void txtenc_field(txtenc *e, upb_msgval val, const upb_fielddef *f) {
       break;
     case UPB_TYPE_MESSAGE:
       txtenc_putstr(e, "{");
+      txtenc_endfield(e);
       e->indent_depth++;
       txtenc_msg(e, val.msg_val, upb_fielddef_msgsubdef(f));
       e->indent_depth--;
@@ -224,6 +223,8 @@ static void txtenc_map(txtenc *e, const upb_map *map, const upb_fielddef *f) {
   }
 }
 
+#define CHK(x) do { if (!(x)) { return false; } } while(0)
+
 static const char *txtenc_parsevarint(const char *ptr, const char *limit,
                                       uint64_t *val) {
   uint8_t byte;
@@ -333,6 +334,8 @@ static const char *txtenc_unknown(txtenc *e, const char *ptr, const char *end,
   return groupnum == -1 ? ptr : NULL;
 }
 
+#undef CHK
+
 static void txtenc_msg(txtenc *e, const upb_msg *msg,
                        const upb_msgdef *m) {
   size_t iter = UPB_MSG_BEGIN;
@@ -389,5 +392,3 @@ size_t upb_textencode(const upb_msg *msg, const upb_msgdef *m,
   txtenc_msg(&e, msg, m);
   return txtenc_nullz(&e, size);
 }
-
-#undef CHK