web: buffer player info and flush on state change

Constant calls from Wasm to JS to replace unchanged elements in the DOM
is not very efficient.

1 files changed, 93 insertions, 7 deletions

diff --git a/web/web_ui.c b/web/web_ui.c
index 7ac4182..070b898 100644
--- a/web/web_ui.c
+++ b/web/web_ui.c
@@ -12,6 +12,90 @@
 
 #include <emscripten/emscripten.h>
 
+struct player_info {
+	char *name, *rem, *sugg;
+	double avg;
+};
+
+struct player_info buffered_info[2], flushed_info[2];
+
+static inline void buffer_str(char *str, char **buffer, char *flushed)
+{
+	if (str == *buffer || (str && *buffer && !strcmp(str, *buffer)))
+		return;
+
+	if (*buffer && *buffer != flushed)
+		free(*buffer);
+
+	*buffer = str ? strdup(str) : NULL;
+}
+
+void ui_set_player_name(int pn, char *str)
+{
+	buffer_str(str, &buffered_info[pn-1].name, flushed_info[pn-1].name);
+}
+
+void ui_set_player_rem(int pn, char *str)
+{
+	buffer_str(str, &buffered_info[pn-1].rem, flushed_info[pn-1].rem);
+}
+
+void ui_set_player_sugg(int pn, char *str)
+{
+	buffer_str(str, &buffered_info[pn-1].sugg, flushed_info[pn-1].sugg);
+}
+
+void ui_set_player_avg(int pn, double avg)
+{
+	buffered_info[pn-1].avg = avg;
+}
+
+static inline bool buffered_str_changed(char *buffered, char *flushed)
+{
+	return (!buffered != !flushed) ||
+		(buffered && flushed && strcmp(buffered, flushed));
+}
+
+static inline void free_flushed_str(char *flushed, char *buffered)
+{
+	if (flushed && flushed != buffered)
+		free(flushed);
+}
+
+void ui_flush_player_info(int pn)
+{
+	if (buffered_str_changed(buffered_info[pn-1].name,
+			flushed_info[pn-1].name))
+		EM_ASM({updatePlayerName($0, $1)}, pn, buffered_info[pn-1].name);
+
+	if (buffered_str_changed(buffered_info[pn-1].rem,
+			flushed_info[pn-1].rem))
+		EM_ASM({updatePlayerRem($0, $1)}, pn, buffered_info[pn-1].rem);
+
+	if (buffered_str_changed(buffered_info[pn-1].sugg,
+			flushed_info[pn-1].sugg))
+		EM_ASM({updatePlayerSugg($0, $1)}, pn, buffered_info[pn-1].sugg);
+
+	if (buffered_info[pn-1].avg != flushed_info[pn-1].avg)
+		EM_ASM({updatePlayerAvg($0, $1)}, pn, buffered_info[pn-1].avg);
+
+	free_flushed_str(flushed_info[pn-1].name, buffered_info[pn-1].name);
+	free_flushed_str(flushed_info[pn-1].rem, buffered_info[pn-1].rem);
+	free_flushed_str(flushed_info[pn-1].sugg, buffered_info[pn-1].sugg);
+	flushed_info[pn-1] = buffered_info[pn-1];
+}
+
+void ui_flush()
+{
+	ui_flush_player_info(1);
+	ui_flush_player_info(2);
+}
+
+void update_player_name(int pn, char *str)
+{
+	ui_set_player_name(pn, str);
+}
+
 void update_player_sugg(int pn, int rem)
 {
 	char str[15] = {0}, *p = str;
@@ -25,13 +109,13 @@ void update_player_sugg(int pn, int rem)
 		}
 	}
 
-	EM_ASM({updatePlayerSugg($0, $1)}, pn, str);
+	ui_set_player_sugg(pn, str);
 }
 
 void update_player_avg(int pn, int n_darts)
 {
 	struct leg *l = state->legs[pn-1];
-	EM_ASM({updatePlayerAvg($0, $1)}, pn,
+	ui_set_player_avg(pn,
 		l->n_visits ?
 			(l->rem > 0 ? ((double)(l->start - l->rem) / l->n_visits) :
 				((double)l->start / (((l->n_visits - 1) * 3) + n_darts) * 3)) :
@@ -88,17 +172,17 @@ void update_player_rem(int pn, int rem)
 	else
 		sprintf(str, "%d", rem);
 
-	EM_ASM({updatePlayerRem($0, $1)}, pn, str);
+	ui_set_player_rem(pn, str);
 	if (pn == 1 || state->mode != M_PVC)
 		update_player_sugg(pn, rem);
 }
 
 void clear_player_info(int pn)
 {
-	EM_ASM({updatePlayerName($0, $1)}, pn, "");
-	EM_ASM({updatePlayerRem($0, $1)}, pn, "");
-	EM_ASM({updatePlayerSugg($0, $1)}, pn, "");
-	EM_ASM({updatePlayerAvg($0, $1)}, pn, 0);
+	ui_set_player_name(pn, "");
+	ui_set_player_rem(pn, "");
+	ui_set_player_sugg(pn, "");
+	ui_set_player_avg(pn, 0);
 }
 
 EMSCRIPTEN_KEEPALIVE
@@ -116,6 +200,8 @@ void draw_boat_throwing(int pts, char *str, double x, double y)
 	EM_ASM({setPromptInput($0)}, pts_str);
 	EM_ASM({promptMsgR($0)}, str);
 	free(str);
+
+	ui_flush_player_info(2); // FIXME bot hard-coded as player 2
 }
 
 bool is_key_active(char *k)