pe: cap shell refresh rate at 30 FPS

README.md

@@ -15,7 +15,6 @@ Most of the code is in `ports/sh` and is shared between the platforms.
 **TODO list**
 
 Bugs to fix:
-- Don't refresh screen at every low-level console print
 - Fix not world switching during filesystem accesses (very unstable)
 
 Python features:
@@ -25,6 +24,8 @@ Python features:
 - Interrupt with AC/ON
 
 UI:
+- Shell escapes: move cursor, history
+- Better input system in the shell
 - Use [JustUI](/Lephenixnoir/JustUI) to get a file browser (already available)
 - Add an option for fixed-width font which also sets $COLUMNS properly so that
   MicroPython paginates (requires better getenv/setenv support in fxlib)

ports/sh/Makefile

@@ -15,6 +15,7 @@ SRC_C = \
     ports/sh/keymap.c \
     ports/sh/modgint.c \
     ports/sh/mphalport.c \
+    ports/sh/shell.c \
     shared/readline/readline.c \
     shared/runtime/gchelper_generic.c \
     shared/runtime/pyexec.c \

ports/sh/main.c

@@ -13,7 +13,9 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
+
 #include "console.h"
+#include "shell.h"
 
 //=== Console-based standard streams ===//
 
@@ -33,33 +35,15 @@ fs_descriptor_type_t stdouterr_type = {
 
 //=== Main function ===//
 
-static console_t *cons = NULL;
-
-void pe_draw(void)
-{
-    dclear(C_WHITE);
-#ifdef FX9860G
-    int rows = 8;
-    console_render(1, 1, cons, DWIDTH-2, rows);
-#else
-    dprint(3, 3, C_BLACK, "PythonExtra, very much WIP :)");
-    dline(2, 16, DWIDTH-3, 16, C_BLACK);
-    int rows = 12;
-    console_render(3, 20, cons, DWIDTH-6, rows);
-    int y = 20 + PE_CONSOLE_LINE_SPACING * rows;
-    dline(2, y, DWIDTH-3, y, C_BLACK);
-#endif
-    dupdate();
-}
-
 int main(int argc, char **argv)
 {
+    pe_shell_init();
+
     /* Set up standard streams */
-    cons = console_create(8192);
     close(STDOUT_FILENO);
     close(STDERR_FILENO);
-    open_generic(&stdouterr_type, cons, STDOUT_FILENO);
-    open_generic(&stdouterr_type, cons, STDERR_FILENO);
+    open_generic(&stdouterr_type, pe_shell_console, STDOUT_FILENO);
+    open_generic(&stdouterr_type, pe_shell_console, STDERR_FILENO);
 
     /* Initialize MicroPython */
     #define HEAP_SIZE 32768
@@ -86,11 +70,10 @@ int main(int argc, char **argv)
     // Start a normal REPL; will exit when ctrl-D is entered on a blank line.
     pyexec_friendly_repl();
 
-    console_destroy(cons);
-
     // Deinitialise the runtime.
     gc_sweep_all();
     mp_deinit();
+    pe_shell_deinit();
     return 0;
 }
 

ports/sh/modgint.c

@@ -2,6 +2,7 @@
 #include "py/objtuple.h"
 #include <gint/display.h>
 #include <gint/keyboard.h>
+#include "shell.h"
 
 #define FUN_0(NAME) \
     MP_DEFINE_CONST_FUN_OBJ_0(modgint_ ## NAME ## _obj, modgint_ ## NAME)
@@ -121,6 +122,7 @@ STATIC mp_obj_t modgint_dclear(mp_obj_t arg1)
 
 STATIC mp_obj_t modgint_dupdate(void)
 {
+    pe_shell_graphics_mode();
     dupdate();
     return mp_const_none;
 }

ports/sh/mphalport.c

@@ -4,11 +4,13 @@
 #include "../../shared/readline/readline.h"
 
 #include "keymap.h"
+#include "shell.h"
 #include <gint/display.h>
 #include <gint/keyboard.h>
 
 // Receive single character, blocking until one is available.
-int mp_hal_stdin_rx_chr(void) {
+int mp_hal_stdin_rx_chr(void)
+{
     while(1) {
         key_event_t ev = getkey();
         int key = ev.key;
@@ -44,10 +46,10 @@ int mp_hal_stdin_rx_chr(void) {
 }
 
 // Send the string of given length.
-void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) {
+void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len)
+{
     int r = write(STDOUT_FILENO, str, len);
     (void)r;
 
-    extern void pe_draw(void);
-    pe_draw();
+    pe_shell_schedule_update();
 }

ports/sh/shell.c

@@ -0,0 +1,63 @@
+#include "shell.h"
+#include <gint/timer.h>
+#include <gint/display.h>
+
+/* The global terminal. */
+console_t *pe_shell_console;
+/* Timer handle for the refresh clock. */
+static int pe_shell_timer = -1;
+/* Whether there is new shell data to be shown on the next frame. */
+static bool pe_shell_update = true;
+
+static void pe_shell_draw(void)
+{
+    dclear(C_WHITE);
+
+#ifdef FX9860G
+    int rows = 8;
+    console_render(1, 1, pe_shell_console, DWIDTH-2, rows);
+#else
+    dprint(3, 3, C_BLACK, "PythonExtra, very much WIP :)");
+    dline(2, 16, DWIDTH-3, 16, C_BLACK);
+    int rows = 12;
+    console_render(3, 20, pe_shell_console, DWIDTH-6, rows);
+    int y = 20 + PE_CONSOLE_LINE_SPACING * rows;
+    dline(2, y, DWIDTH-3, y, C_BLACK);
+#endif
+
+    dupdate();
+}
+
+static int pe_shell_timer_handler(void)
+{
+    if(pe_shell_update) {
+        pe_shell_draw();
+        pe_shell_update = false;
+    }
+    return TIMER_CONTINUE;
+}
+
+void pe_shell_schedule_update(void)
+{
+    pe_shell_update = true;
+}
+
+void pe_shell_graphics_mode(void)
+{
+    pe_shell_update = false;
+}
+
+void pe_shell_init(void)
+{
+    pe_shell_console = console_create(8192);
+
+    pe_shell_timer = timer_configure(TIMER_ANY, 1000000 / PE_SHELL_FPS,
+        GINT_CALL(pe_shell_timer_handler));
+    timer_start(pe_shell_timer);
+}
+
+void pe_shell_deinit(void)
+{
+    timer_stop(pe_shell_timer);
+    console_destroy(pe_shell_console);
+}

ports/sh/shell.h

@@ -0,0 +1,46 @@
+// pe.shell: Shell integration
+//
+// This header covers application-integration aspects of the shell. For the
+// implementation of the console itself (input, escape sequences, etc). see
+// <console.h> instead.
+//
+// The shell consists of a terminal-emulating `console_t` along with some input
+// UI. During execution, the shell is redrawn only (1) when new data is printed
+// or requested, and (2) a fixed refresh timer hits. Condition 1 avoids
+// needless updates for non-printing programs, while condition 2 prevents
+// performance issues for sequences that print one character at a time (which
+// is quite common even within MicroPython builtins).
+//
+// If the built-in function gint.dupdate() is used, the shell also hands over
+// display updates to "graphics mode", where only manual dupdate() calls push
+// the VRAM. Switching to graphics mode cancels any scheduled shell updates.
+// Graphics mode is exited once a new shell update is explicity scheduled,
+// typically by a call to print() or input().
+//---
+
+#ifndef __PYTHONEXTRA_SHELL_H
+#define __PYTHONEXTRA_SHELL_H
+
+#include "console.h"
+
+/* Shell frame frequency, ie. cap on the number of shell redraws per second. */
+#define PE_SHELL_FPS 30
+
+/* The terminal. */
+extern console_t *pe_shell_console;
+
+/* Schedule a redraw of the shell interface at the next shell frame. This is
+   called whenever data is printed into the shell or input() is used. The
+   scheduled redraw might be canceled by switching to graphics mode before the
+   frame timer fires. */
+void pe_shell_schedule_update(void);
+
+/* Switch to graphics mode. This cancels pending shell updates. */
+void pe_shell_graphics_mode(void);
+
+//=== Internal functions ===//
+
+void pe_shell_init(void);
+void pe_shell_deinit(void);
+
+#endif /* __PYTHONEXTRA_SHELL_H */