refactor(api): refactor more api functions to use arena return

Currently having two separate memory strategies for API return values is
a bit unnecessary, and mostly a consequence of converting the hot spot
cases which needed it first. But there is really no downside to using
arena everywhere (which implies also directly using strings which are
allocated earlier or even statically, without copy).

There only restriction is we need to know the size of arrays in advance,
but this info can often be passed on from some earlier stage if it is
missing.

This collects some "small" cases. The more complex stuff will get a PR
each.

1 files changed, 42 insertions, 40 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index b1bfdd79e7..1453de30d4 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1351,14 +1351,13 @@ Integer nvim_get_color_by_name(String name)
 /// (e.g. 65535).
 ///
 /// @return Map of color names and RGB values.
-Dictionary nvim_get_color_map(void)
+Dictionary nvim_get_color_map(Arena *arena)
   FUNC_API_SINCE(1)
 {
-  Dictionary colors = ARRAY_DICT_INIT;
+  Dictionary colors = arena_dict(arena, ARRAY_SIZE(color_name_table));
 
   for (int i = 0; color_name_table[i].name != NULL; i++) {
-    PUT(colors, color_name_table[i].name,
-        INTEGER_OBJ(color_name_table[i].color));
+    PUT_C(colors, color_name_table[i].name, INTEGER_OBJ(color_name_table[i].color));
   }
   return colors;
 }
@@ -1438,16 +1437,16 @@ Object nvim_load_context(Dictionary dict, Error *err)
 /// "blocking" is true if Nvim is waiting for input.
 ///
 /// @returns Dictionary { "mode": String, "blocking": Boolean }
-Dictionary nvim_get_mode(void)
+Dictionary nvim_get_mode(Arena *arena)
   FUNC_API_SINCE(2) FUNC_API_FAST
 {
-  Dictionary rv = ARRAY_DICT_INIT;
-  char modestr[MODE_MAX_LENGTH];
+  Dictionary rv = arena_dict(arena, 2);
+  char *modestr = arena_alloc(arena, MODE_MAX_LENGTH, false);
   get_mode(modestr);
   bool blocked = input_blocking();
 
-  PUT(rv, "mode", CSTR_TO_OBJ(modestr));
-  PUT(rv, "blocking", BOOLEAN_OBJ(blocked));
+  PUT_C(rv, "mode", CSTR_AS_OBJ(modestr));
+  PUT_C(rv, "blocking", BOOLEAN_OBJ(blocked));
 
   return rv;
 }
@@ -1848,14 +1847,14 @@ Float nvim__id_float(Float flt)
 /// Gets internal stats.
 ///
 /// @return Map of various internal stats.
-Dictionary nvim__stats(void)
-{
-  Dictionary rv = ARRAY_DICT_INIT;
-  PUT(rv, "fsync", INTEGER_OBJ(g_stats.fsync));
-  PUT(rv, "log_skip", INTEGER_OBJ(g_stats.log_skip));
-  PUT(rv, "lua_refcount", INTEGER_OBJ(nlua_get_global_ref_count()));
-  PUT(rv, "redraw", INTEGER_OBJ(g_stats.redraw));
-  PUT(rv, "arena_alloc_count", INTEGER_OBJ((Integer)arena_alloc_count));
+Dictionary nvim__stats(Arena *arena)
+{
+  Dictionary rv = arena_dict(arena, 5);
+  PUT_C(rv, "fsync", INTEGER_OBJ(g_stats.fsync));
+  PUT_C(rv, "log_skip", INTEGER_OBJ(g_stats.log_skip));
+  PUT_C(rv, "lua_refcount", INTEGER_OBJ(nlua_get_global_ref_count()));
+  PUT_C(rv, "redraw", INTEGER_OBJ(g_stats.redraw));
+  PUT_C(rv, "arena_alloc_count", INTEGER_OBJ((Integer)arena_alloc_count));
   return rv;
 }
 
@@ -2151,7 +2150,7 @@ Array nvim_get_mark(String name, Dict(empty) *opts, Error *err)
 ///                     |Dictionary| with these keys:
 ///           - start: (number) Byte index (0-based) of first character that uses the highlight.
 ///           - group: (string) Name of highlight group.
-Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *err)
+Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Arena *arena, Error *err)
   FUNC_API_SINCE(8) FUNC_API_FAST
 {
   Dictionary result = ARRAY_DICT_INIT;
@@ -2260,58 +2259,61 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
                                      && global_stl_height() > 0)) ? Columns : wp->w_width;
   }
 
-  char buf[MAXPATHL];
+  result = arena_dict(arena, 3);
+  char *buf = arena_alloc(arena, MAXPATHL, false);
   stl_hlrec_t *hltab;
+  size_t hltab_len = 0;
 
   // Temporarily reset 'cursorbind' to prevent side effects from moving the cursor away and back.
   int p_crb_save = wp->w_p_crb;
   wp->w_p_crb = false;
 
-  int width = build_stl_str_hl(wp, buf, sizeof(buf), str.data, -1, 0, fillchar, maxwidth,
-                               opts->highlights ? &hltab : NULL, NULL,
+  int width = build_stl_str_hl(wp, buf, MAXPATHL, str.data, -1, 0, fillchar, maxwidth,
+                               opts->highlights ? &hltab : NULL, &hltab_len, NULL,
                                statuscol_lnum ? &statuscol : NULL);
 
-  PUT(result, "width", INTEGER_OBJ(width));
+  PUT_C(result, "width", INTEGER_OBJ(width));
 
   // Restore original value of 'cursorbind'
   wp->w_p_crb = p_crb_save;
 
   if (opts->highlights) {
-    Array hl_values = ARRAY_DICT_INIT;
-    const char *grpname;
+    Array hl_values = arena_array(arena, hltab_len + 1);
     char user_group[15];  // strlen("User") + strlen("2147483647") + NUL
 
     // If first character doesn't have a defined highlight,
     // add the default highlight at the beginning of the highlight list
     if (hltab->start == NULL || (hltab->start - buf) != 0) {
-      Dictionary hl_info = ARRAY_DICT_INIT;
-      grpname = get_default_stl_hl(opts->use_tabline ? NULL : wp, opts->use_winbar, stc_hl_id);
+      Dictionary hl_info = arena_dict(arena, 2);
+      const char *grpname = get_default_stl_hl(opts->use_tabline ? NULL : wp,
+                                               opts->use_winbar, stc_hl_id);
 
-      PUT(hl_info, "start", INTEGER_OBJ(0));
-      PUT(hl_info, "group", CSTR_TO_OBJ(grpname));
+      PUT_C(hl_info, "start", INTEGER_OBJ(0));
+      PUT_C(hl_info, "group", CSTR_AS_OBJ((char *)grpname));
 
-      ADD(hl_values, DICTIONARY_OBJ(hl_info));
+      ADD_C(hl_values, DICTIONARY_OBJ(hl_info));
     }
 
     for (stl_hlrec_t *sp = hltab; sp->start != NULL; sp++) {
-      Dictionary hl_info = ARRAY_DICT_INIT;
+      Dictionary hl_info = arena_dict(arena, 2);
 
-      PUT(hl_info, "start", INTEGER_OBJ(sp->start - buf));
+      PUT_C(hl_info, "start", INTEGER_OBJ(sp->start - buf));
 
+      const char *grpname;
       if (sp->userhl == 0) {
         grpname = get_default_stl_hl(opts->use_tabline ? NULL : wp, opts->use_winbar, stc_hl_id);
       } else if (sp->userhl < 0) {
         grpname = syn_id2name(-sp->userhl);
       } else {
         snprintf(user_group, sizeof(user_group), "User%d", sp->userhl);
-        grpname = user_group;
+        grpname = arena_memdupz(arena, user_group, strlen(user_group));
       }
-      PUT(hl_info, "group", CSTR_TO_OBJ(grpname));
-      ADD(hl_values, DICTIONARY_OBJ(hl_info));
+      PUT_C(hl_info, "group", CSTR_AS_OBJ((char *)grpname));
+      ADD_C(hl_values, DICTIONARY_OBJ(hl_info));
     }
-    PUT(result, "highlights", ARRAY_OBJ(hl_values));
+    PUT_C(result, "highlights", ARRAY_OBJ(hl_values));
   }
-  PUT(result, "str", CSTR_TO_OBJ(buf));
+  PUT_C(result, "str", CSTR_AS_OBJ(buf));
 
   return result;
 }
@@ -2336,15 +2338,15 @@ void nvim_error_event(uint64_t channel_id, Integer lvl, String data)
 /// @return Dictionary containing these keys:
 ///       - winid: (number) floating window id
 ///       - bufnr: (number) buffer id in floating window
-Dictionary nvim_complete_set(Integer index, Dict(complete_set) *opts)
+Dictionary nvim_complete_set(Integer index, Dict(complete_set) *opts, Arena *arena)
   FUNC_API_SINCE(12)
 {
-  Dictionary rv = ARRAY_DICT_INIT;
+  Dictionary rv = arena_dict(arena, 2);
   if (HAS_KEY(opts, complete_set, info)) {
     win_T *wp = pum_set_info((int)index, opts->info.data);
     if (wp) {
-      PUT(rv, "winid", WINDOW_OBJ(wp->handle));
-      PUT(rv, "bufnr", BUFFER_OBJ(wp->w_buffer->handle));
+      PUT_C(rv, "winid", WINDOW_OBJ(wp->handle));
+      PUT_C(rv, "bufnr", BUFFER_OBJ(wp->w_buffer->handle));
     }
   }
   return rv;