Add history/line-edit function to Ctrl-t command string input

Ctrl-t r/R/x/y commands require string input. To reduce the hassle of
repeatedly entering this information, I apply readline functions
(line-editing and history) to the string input.

Now tio have two histories: one for the line input-mode and one for the
ctrl-t command's string input.

And the following changes are made to the line input:
- Add prompts.
  "> ": line input-mode, ">> " Ctrl-t string input.
- Omits duplicate lines from the history.

To implement the above functionality, we will modify the readline
functions to use the multi-instance style.

src/readline.c

@@ -19,85 +19,133 @@
  * 02110-1301, USA.
  */
 
+#include "readline.h"
 #include "print.h"
 #include "misc.h"
+#include <assert.h>
 
 #define RL_LINE_LENGTH_MAX PATH_MAX
-#define RL_HISTORY_MAX 1000
 
-static char rl_line[RL_LINE_LENGTH_MAX] = {};
-static char *rl_history[RL_HISTORY_MAX];
-static int rl_history_count = 0;
-static int rl_history_index = 0;
-static int rl_line_length = 0;
-static int rl_cursor_pos = 0;
-static int rl_escape = 0;
+typedef struct readline_s
+{
+    char line[RL_LINE_LENGTH_MAX];
+    char *history[RL_HISTORY_MAX];
+    char prompt[RL_PROMPT_LENGTH_MAX];
+    int prompt_length;
+    int history_count;
+    int history_index;
+    int line_length;
+    int cursor_pos;
+    int escape;
+} readline_t;
 
-static void print_line(const char *string, int cursor_pos)
+void print_line(readline_t *rl)
 {
     clear_line();
-    print("%s", string);
+    print("%s%s", rl->prompt, rl->line);
     print("\r"); // Move the cursor back to the beginning
-    for (int i = 0; i < cursor_pos; ++i)
+    for (int i = 0; i < rl->prompt_length + rl->cursor_pos; ++i)
     {
         print("\x1b[C"); // Move the cursor right
     }
 }
 
-void readline_init(void)
+readline_t *readline_create(void)
 {
-    rl_history_count = 0;
-    rl_history_index = 0;
+    readline_t *rl = malloc(sizeof(readline_t));
+    if (rl == NULL)
+        return NULL;
+
+    readline_reinit(rl);
+    return rl;
+}
+
+void readline_reinit(readline_t *rl)
+{
+    assert(rl != NULL);
+
+    rl->prompt[0] = '\0';
+    rl->prompt_length = 0;
+
+    rl->history_count = 0;
+    rl->history_index = 0;
 
     for (int i = 0; i < RL_HISTORY_MAX; ++i)
     {
-        rl_history[i] = NULL;
+        rl->history[i] = NULL;
     }
 
-    rl_line[0] = 0;
-    rl_line_length = 0;
-    rl_cursor_pos = 0;
-    rl_escape = 0;
+    rl->line[0] = 0;
+    rl->line_length = 0;
+    rl->cursor_pos = 0;
+    rl->escape = 0;
 }
 
-char * readline_get(void)
+void readline_set_prompt(readline_t *rl, const char *prompt)
 {
-    return rl_line;
+    strncpy(rl->prompt, prompt, RL_PROMPT_LENGTH_MAX - 1);
+    rl->prompt[RL_PROMPT_LENGTH_MAX - 1] = '\0';
+    rl->prompt_length = strlen(rl->prompt);
 }
 
-static void readline_input_char(char input_char)
+char * readline_get(readline_t *rl)
 {
-    if (rl_line_length < RL_LINE_LENGTH_MAX - 1)
+    assert(rl != NULL);
+    return rl->line;
+}
+
+void readline_prompt_for_input(readline_t *rl)
+{
+    assert(rl != NULL);
+
+    rl->line[0] = 0;
+    rl->line_length = 0;
+    rl->cursor_pos = 0;
+    rl->escape = 0;
+    print_line(rl);
+}
+
+static void readline_input_char(readline_t *rl, char input_char)
+{
+    assert(rl != NULL);
+
+    if (rl->line_length < RL_LINE_LENGTH_MAX - 1)
     {
-        memmove(&rl_line[rl_cursor_pos + 1], &rl_line[rl_cursor_pos], rl_line_length - rl_cursor_pos);
-        rl_line[rl_cursor_pos] = input_char;
-        rl_line_length++;
-        rl_cursor_pos++;
-        rl_line[rl_line_length] = '\0';
-        print_line(rl_line, rl_cursor_pos);
+        memmove(&rl->line[rl->cursor_pos + 1], &rl->line[rl->cursor_pos], rl->line_length - rl->cursor_pos);
+        rl->line[rl->cursor_pos] = input_char;
+        rl->line_length++;
+        rl->cursor_pos++;
+        rl->line[rl->line_length] = '\0';
+        print_line(rl);
     }
-    rl_escape = 0;
+    rl->escape = 0;
 }
 
-static void readline_input_cr(void)
+static void readline_input_cr(readline_t *rl)
 {
-    if (rl_line_length > 0)
+    rl->line[rl->line_length] = '\0';
+
+    if (rl->line_length > 0)
     {
-        // Save to history
-        if (rl_history_count < RL_HISTORY_MAX)
+        // Different line only
+        if (rl->history_count == 0 ||
+            (rl->history_count > 0 && strncmp(rl->history[rl->history_count - 1], rl->line, rl->line_length) != 0))
         {
-            rl_history[rl_history_count] = strndup(rl_line, rl_line_length);
-            rl_history_count++;
-        }
-        else
-        {
-            free(rl_history[0]);
-            memmove(&rl_history[0], &rl_history[1], (RL_HISTORY_MAX - 1) * sizeof(char*));
-            rl_history[RL_HISTORY_MAX - 1] = strndup(rl_line, rl_line_length);
+            // Save to history
+            if (rl->history_count < RL_HISTORY_MAX)
+            {
+                rl->history[rl->history_count] = strndup(rl->line, rl->line_length);
+                rl->history_count++;
+            }
+            else
+            {
+                free(rl->history[0]);
+                memmove(&rl->history[0], &rl->history[1], (RL_HISTORY_MAX - 1) * sizeof(char*));
+                rl->history[RL_HISTORY_MAX - 1] = strndup(rl->line, rl->line_length);
+            }
         }
     }
 
-    rl_line[rl_line_length] = '\0';
     if (option.local_echo == false)
     {
         clear_line();
@@ -107,170 +155,171 @@ static void readline_input_cr(void)
         print("\r\n");
     }
 
-    rl_line_length = 0;
-    rl_cursor_pos = 0;
-    rl_history_index = rl_history_count;
-    rl_escape = 0;
+    rl->line_length = 0;
+    rl->cursor_pos = 0;
+    rl->history_index = rl->history_count;
+    rl->escape = 0;
 }
 
-static void readline_input_bs(void)
+static void readline_input_bs(readline_t *rl)
 {
-    if (rl_cursor_pos > 0)
+    if (rl->cursor_pos > 0)
     {
-        memmove(&rl_line[rl_cursor_pos - 1], &rl_line[rl_cursor_pos], rl_line_length - rl_cursor_pos);
-        rl_line_length--;
-        rl_cursor_pos--;
-        rl_line[rl_line_length] = '\0';
-        print_line(rl_line, rl_cursor_pos);
+        memmove(&rl->line[rl->cursor_pos - 1], &rl->line[rl->cursor_pos], rl->line_length - rl->cursor_pos);
+        rl->line_length--;
+        rl->cursor_pos--;
+        rl->line[rl->line_length] = '\0';
+        print_line(rl);
     }
-    rl_escape = 0;
+    rl->escape = 0;
 }
 
-static void readline_input_escape(void)
+static void readline_input_escape(readline_t *rl)
 {
-    rl_escape = 1;
+    rl->escape = 1;
 }
 
-static void readline_input_left_bracket(void)
+static void readline_input_left_bracket(readline_t *rl)
 {
-    if (rl_escape == 1)
+    if (rl->escape == 1)
     {
-        rl_escape = 2;
+        rl->escape = 2;
     }
     else
     {
-        rl_escape = 0;
+        readline_input_char(rl, '[');
+        rl->escape = 0;
     }
 }
 
-static void readline_input_A(void)
+static void readline_input_A(readline_t *rl)
 {
-    if (rl_escape == 2)
+    if (rl->escape == 2)
     {
         // Up arrow
-        if (rl_history_index > 0)
+        if (rl->history_index > 0)
         {
-            rl_history_index--;
-            strncpy(rl_line, rl_history[rl_history_index], RL_LINE_LENGTH_MAX-1);
-            rl_line_length = strlen(rl_line);
-            rl_cursor_pos = rl_line_length;
-            print_line(rl_line, rl_cursor_pos);
+            rl->history_index--;
+            strncpy(rl->line, rl->history[rl->history_index], RL_LINE_LENGTH_MAX-1);
+            rl->line_length = strlen(rl->line);
+            rl->cursor_pos = rl->line_length;
+            print_line(rl);
         }
     }
     else
     {
-        readline_input_char('A');
+        readline_input_char(rl, 'A');
     }
 
-    rl_escape = 0;
+    rl->escape = 0;
 }
 
-static void readline_input_B(void)
+static void readline_input_B(readline_t *rl)
 {
-    if (rl_escape == 2)
+    if (rl->escape == 2)
     {
         // Down arrow
-        if (rl_history_index < rl_history_count - 1)
+        if (rl->history_index < rl->history_count - 1)
         {
-            rl_history_index++;
-            strncpy(rl_line, rl_history[rl_history_index], RL_LINE_LENGTH_MAX-1);
-            rl_line_length = strlen(rl_line);
-            rl_cursor_pos = rl_line_length;
-            print_line(rl_line, rl_cursor_pos);
+            rl->history_index++;
+            strncpy(rl->line, rl->history[rl->history_index], RL_LINE_LENGTH_MAX-1);
+            rl->line_length = strlen(rl->line);
+            rl->cursor_pos = rl->line_length;
+            print_line(rl);
         }
-        else if (rl_history_index == rl_history_count - 1)
+        else if (rl->history_index == rl->history_count - 1)
         {
-            rl_history_index++;
-            rl_line_length = 0;
-            rl_cursor_pos = 0;
-            rl_line[rl_line_length] = '\0';
-            print_line(rl_line, rl_cursor_pos);
+            rl->history_index++;
+            rl->line_length = 0;
+            rl->cursor_pos = 0;
+            rl->line[rl->line_length] = '\0';
+            print_line(rl);
         }
     }
     else
     {
-        readline_input_char('B');
+        readline_input_char(rl, 'B');
     }
 
-    rl_escape = 0;
+    rl->escape = 0;
 }
 
-static void readline_input_C(void)
+static void readline_input_C(readline_t *rl)
 {
-    if (rl_escape == 2)
+    if (rl->escape == 2)
     {
         // Right arrow
-        if (rl_cursor_pos < rl_line_length)
+        if (rl->cursor_pos < rl->line_length)
         {
-            rl_cursor_pos++;
+            rl->cursor_pos++;
             print("\x1b[C");
         }
     }
     else
     {
-        readline_input_char('C');
+        readline_input_char(rl, 'C');
     }
 
-    rl_escape = 0;
+    rl->escape = 0;
 }
 
-static void readline_input_D(void)
+static void readline_input_D(readline_t *rl)
 {
-    if (rl_escape == 2)
+    if (rl->escape == 2)
     {
         // Left arrow
-        if (rl_cursor_pos > 0)
+        if (rl->cursor_pos > 0)
         {
-            rl_cursor_pos--;
+            rl->cursor_pos--;
             print("\b");
         }
     }
     else
     {
-        readline_input_char('D');
+        readline_input_char(rl, 'D');
     }
 
-    rl_escape = 0;
+    rl->escape = 0;
 }
 
-void readline_input(char input_char)
+void readline_input(readline_t *rl, char input_char)
 {
     switch (input_char)
     {
         case '\r': // Carriage return
-            readline_input_cr();
+            readline_input_cr(rl);
             break;
 
         case 127: // Backspace
-            readline_input_bs();
+            readline_input_bs(rl);
             break;
 
         case 27: // Escape
-            readline_input_escape();
+            readline_input_escape(rl);
             break;
 
         case '[':
-            readline_input_left_bracket();
+            readline_input_left_bracket(rl);
             break;
 
         case 'A':
-            readline_input_A();
+            readline_input_A(rl);
             break;
 
         case 'B':
-            readline_input_B();
+            readline_input_B(rl);
             break;
 
         case 'C':
-            readline_input_C();
+            readline_input_C(rl);
             break;
 
         case 'D':
-            readline_input_D();
+            readline_input_D(rl);
             break;
 
         default:
-            readline_input_char(input_char);
+            readline_input_char(rl, input_char);
             break;
     }
 }

src/readline.h

@@ -21,6 +21,14 @@
 
 #pragma once
 
-void readline_init(void);
-void readline_input(char input_char);
-char * readline_get(void);
+#define RL_HISTORY_MAX 1000
+#define RL_PROMPT_LENGTH_MAX 16
+
+typedef struct readline_s readline_t;
+
+readline_t *readline_create(void);
+void readline_reinit(readline_t *rl);
+void readline_set_prompt(readline_t *rl, const char *prompt);
+void readline_prompt_for_input(readline_t *rl);
+void readline_input(readline_t *rl, char input_char);
+char *readline_get(readline_t *rl);

src/tty.c

@@ -185,6 +185,8 @@ static int pipefd[2];
 static pthread_mutex_t mutex_input_ready = PTHREAD_MUTEX_INITIALIZER;
 static char line[PATH_MAX];
 static size_t listing_device_name_length_max = 0;
+static readline_t *readline_ctx = NULL;
+static readline_t *subcmd_readline_ctx = NULL;
 
 static void optional_local_echo(char c)
 {
@@ -589,31 +591,25 @@ static void tty_line_poke(int fd, int mask, tty_line_mode_t mode, unsigned int d
     }
 }
 
-static int tio_readln(void)
+static int tio_subcmd_readln(const char *title_prompt)
 {
-    char *p = line;
+    tio_printf_raw("%s\r\n", title_prompt);
+    readline_prompt_for_input(subcmd_readline_ctx);
 
-    /* Read line, accept BS and DEL as rubout characters */
-    for (p = line ; p < &line[PATH_MAX-1]; )
+    /* Read line with line edit and history. */
+    char c;
+    while (true)
     {
-        if (read(pipefd[0], p, 1) > 0)
+        if (read(pipefd[0], &c, 1) > 0)
         {
-            if (*p == 0x08 || *p == 0x7f)
-            {
-                if (p > line)
-                {
-                    write(STDOUT_FILENO, "\b \b", 3);
-                    p--;
-                }
-                continue;
-            }
-            write(STDOUT_FILENO, p, 1);
-            if (*p == '\r') break;
-            p++;
+            readline_input(subcmd_readline_ctx, c);
+            if (c == '\r') break;
         }
     }
-    *p = 0;
-    return (p - line);
+    strncpy(line, readline_get(subcmd_readline_ctx), PATH_MAX - 1);
+    line[PATH_MAX - 1] = 0;
+
+    return strlen(line);
 }
 
 void tty_output_mode_set(output_mode_t mode)
@@ -727,8 +723,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
                 {
                     case KEY_0:
                         tio_printf("Send file with XMODEM-1K");
-                        tio_printf_raw("Enter file name: ");
-                        if (tio_readln())
+                        if (tio_subcmd_readln("Enter file name: "))
                         {
                             int ret;
 
@@ -741,8 +736,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
 
                     case KEY_1:
                         tio_printf("Send file with XMODEM-CRC");
-                        tio_printf_raw("Enter file name: ");
-                        if (tio_readln())
+                        if (tio_subcmd_readln("Enter file name: "))
                         {
                             int ret;
 
@@ -755,8 +749,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
 
                     case KEY_2:
                         tio_printf("Receive file with XMODEM-CRC");
-                        tio_printf_raw("Enter file name: ");
-                        if (tio_readln())
+                        if (tio_subcmd_readln("Enter file name: "))
                         {
                             int ret;
 
@@ -769,8 +762,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
 
                     case KEY_3:
                         tio_printf("Send file with XMODEM-SUM");
-                        tio_printf_raw("Enter file name: ");
-                        if (tio_readln())
+                        if (tio_subcmd_readln("Enter file name: "))
                         {
                             int ret;
 
@@ -783,8 +775,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
 
                     case KEY_4:
                         tio_printf("Receive file with XMODEM-SUM");
-                        tio_printf_raw("Enter file name: ");
-                        if (tio_readln())
+                        if (tio_subcmd_readln("Enter file name: "))
                         {
                             int ret;
 
@@ -1087,8 +1078,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
             case KEY_R:
                 /* Run script */
                 tio_printf("Run Lua script");
-                tio_printf_raw("Enter file name: ");
-                if (tio_readln())
+                if (tio_subcmd_readln("Enter file name: "))
                 {
                     clear_line();
                     script_run(device_fd, line);
@@ -1103,8 +1093,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
             case KEY_SHIFT_R:
                 /* Execute shell command */
                 tio_printf("Execute shell command with I/O redirected to device");
-                tio_printf_raw("Enter command: ");
-                if (tio_readln())
+                if (tio_subcmd_readln("Enter command: "))
                     execute_shell_command(device_fd, line);
                 break;
 
@@ -1163,8 +1152,7 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
 
             case KEY_Y:
                 tio_printf("Send file with YMODEM");
-                tio_printf_raw("Enter file name: ");
-                if (tio_readln())
+                if (tio_subcmd_readln("Enter file name: "))
                 {
                     int ret;
 
@@ -2718,7 +2706,15 @@ int tty_connect(void)
     }
 
     // Initialize readline like history
-    readline_init();
+    readline_ctx = readline_create();
+    subcmd_readline_ctx = readline_create();
+    if (readline_ctx == NULL || subcmd_readline_ctx == NULL)
+    {
+        tio_error_printf("Could not allocate readline buffer.");
+        exit(EXIT_FAILURE);
+    }
+    readline_set_prompt(readline_ctx, "> ");
+    readline_set_prompt(subcmd_readline_ctx, ">> ");
 
     /* Input loop */
     while (true)
@@ -2972,15 +2968,15 @@ int tty_connect(void)
                                     if (input_char == '\r')
                                     {
                                         // Carriage return
-                                        readline_input(input_char);
+                                        readline_input(readline_ctx, input_char);
 
                                         // Write current line to tty device
-                                        char *rl_line = readline_get();
+                                        char *rl_line = readline_get(readline_ctx);
                                         tty_write(device_fd, rl_line, strlen(rl_line));
                                     }
                                     else
                                     {
-                                        readline_input(input_char);
+                                        readline_input(readline_ctx, input_char);
                                         forward = false;
                                     }
                                     break;