server/telnet: simplify telnet_input function

running complexity on this file tells that:
NOTE: proc telnet_input in file telnet_server.c line 576
	nesting depth reached level 8
==>	*seriously consider rewriting the procedure*.
Complexity Scores
Score | ln-ct | nc-lns| file-name(line): proc-name
  319     272     226   src/server/telnet_server.c(576): telnet_input
total nc-lns      226

so try to reduce the complexity score of telnet_input function

Change-Id: I64ecb0c54da83c27a343f2a1df99fc8f9484572a
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6440
Tested-by: jenkins
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

diff --git a/src/server/telnet_server.c b/src/server/telnet_server.c
index 36b017c58ebb2916d81ad42b7ca0e5b6c5eca4e4..13fbc3fda61fe0d42acc5b6873cc72085233ac01 100644 (file)
--- a/src/server/telnet_server.c
+++ b/src/server/telnet_server.c
@@ -320,6 +320,32 @@ static void telnet_history_down(struct connection *connection)
        telnet_history_go(connection, next_history);
 }
 
+static void telnet_history_add(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       /* save only non-blank not repeating lines in the history */
+       char *prev_line = t_con->history[(t_con->current_history > 0) ?
+                       t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
+
+       if (*t_con->line && (!prev_line || strcmp(t_con->line, prev_line))) {
+               /* if the history slot is already taken, free it */
+               free(t_con->history[t_con->next_history]);
+
+               /* add line to history */
+               t_con->history[t_con->next_history] = strdup(t_con->line);
+
+               /* wrap history at TELNET_LINE_HISTORY_SIZE */
+               t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
+
+               /* current history line starts at the new entry */
+               t_con->current_history = t_con->next_history;
+
+               free(t_con->history[t_con->current_history]);
+               t_con->history[t_con->current_history] = strdup("");
+       }
+}
+
 static int telnet_history_print(struct connection *connection)
 {
        struct telnet_connection *tc;
@@ -423,6 +449,137 @@ static bool telnet_insert(struct connection *connection, const void *data, size_
        return true;
 }
 
+static void telnet_delete_character(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       if (t_con->line_cursor == 0)
+               return;
+
+       if (t_con->line_cursor != t_con->line_size) {
+               size_t i;
+               telnet_write(connection, "\b", 1);
+               t_con->line_cursor--;
+               t_con->line_size--;
+               memmove(t_con->line + t_con->line_cursor,
+                               t_con->line + t_con->line_cursor + 1,
+                               t_con->line_size -
+                               t_con->line_cursor);
+
+               telnet_write(connection,
+                               t_con->line + t_con->line_cursor,
+                               t_con->line_size -
+                               t_con->line_cursor);
+               telnet_write(connection, " \b", 2);
+               for (i = t_con->line_cursor; i < t_con->line_size; i++)
+                       telnet_write(connection, "\b", 1);
+       } else {
+               t_con->line_size--;
+               t_con->line_cursor--;
+               /* back space: move the 'printer' head one char
+                * back, overwrite with space, move back again */
+               telnet_write(connection, "\b \b", 3);
+       }
+}
+
+static void telnet_remove_character(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       if (t_con->line_cursor < t_con->line_size) {
+               size_t i;
+               t_con->line_size--;
+               /* remove char from line buffer */
+               memmove(t_con->line + t_con->line_cursor,
+                               t_con->line + t_con->line_cursor + 1,
+                               t_con->line_size - t_con->line_cursor);
+
+               /* print remainder of buffer */
+               telnet_write(connection, t_con->line + t_con->line_cursor,
+                               t_con->line_size - t_con->line_cursor);
+               /* overwrite last char with whitespace */
+               telnet_write(connection, " \b", 2);
+
+               /* move back to cursor position*/
+               for (i = t_con->line_cursor; i < t_con->line_size; i++)
+                       telnet_write(connection, "\b", 1);
+       }
+}
+
+static int telnet_exec_line(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+       struct command_context *command_context = connection->cmd_ctx;
+       int retval;
+
+       telnet_write(connection, "\r\n\x00", 3);
+
+       if (strcmp(t_con->line, "history") == 0) {
+               retval = telnet_history_print(connection);
+
+               if (retval != ERROR_OK)
+                       return retval;
+
+               return ERROR_OK;
+       }
+
+       telnet_history_add(connection);
+
+       t_con->line_size = 0;
+
+       /* to suppress prompt in log callback during command execution */
+       t_con->prompt_visible = false;
+
+       if (strcmp(t_con->line, "shutdown") == 0)
+               telnet_save_history(t_con);
+
+       retval = command_run_line(command_context, t_con->line);
+
+       t_con->line_cursor = 0;
+       t_con->prompt_visible = true;
+
+       if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
+               return ERROR_SERVER_REMOTE_CLOSED;
+
+       /* the prompt is always placed at the line beginning */
+       telnet_write(connection, "\r", 1);
+
+       retval = telnet_prompt(connection);
+       if (retval == ERROR_SERVER_REMOTE_CLOSED)
+               return ERROR_SERVER_REMOTE_CLOSED;
+
+       return ERROR_OK;
+}
+
+static void telnet_cut_line_to_end(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       /* FIXME: currently this function does not save to clipboard */
+
+       if (t_con->line_cursor < t_con->line_size) {
+               /* overwrite with space, until end of line, move back */
+               for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+                       telnet_write(connection, " ", 1);
+               for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+                       telnet_write(connection, "\b", 1);
+               t_con->line[t_con->line_cursor] = '\0';
+               t_con->line_size = t_con->line_cursor;
+       }
+}
+
+static void telnet_interrupt(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       /* print '^C' at line end, and display a new command prompt */
+       telnet_move_cursor(connection, t_con->line_size);
+       telnet_write(connection, "^C\n\r", 4);
+       t_con->line_cursor = 0;
+       t_con->line_size = 0;
+       telnet_prompt(connection);
+}
+
 static void telnet_auto_complete(struct connection *connection)
 {
        struct telnet_connection *t_con = connection->priv;
@@ -591,7 +748,6 @@ static int telnet_input(struct connection *connection)
        unsigned char buffer[TELNET_BUFFER_SIZE];
        unsigned char *buf_p;
        struct telnet_connection *t_con = connection->priv;
-       struct command_context *command_context = connection->cmd_ctx;
 
        bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
 
@@ -630,108 +786,20 @@ static int telnet_input(struct connection *connection)
                                                        }
                                                        t_con->line[t_con->line_size] = 0;
 
-                                                       telnet_write(connection, "\r\n\x00", 3);
-
-                                                       if (strcmp(t_con->line, "history") == 0) {
-                                                               retval = telnet_history_print(connection);
-
-                                                               if (retval != ERROR_OK)
-                                                                       return retval;
-
-                                                               continue;
-                                                       }
-
-                                                       /* save only non-blank not repeating lines in the history */
-                                                       char *prev_line = t_con->history[(t_con->current_history > 0) ?
-                                                                       t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
-                                                       if (*t_con->line && (!prev_line ||
-                                                                       strcmp(t_con->line, prev_line))) {
-                                                               /* if the history slot is already taken, free it */
-                                                               free(t_con->history[t_con->next_history]);
-
-                                                               /* add line to history */
-                                                               t_con->history[t_con->next_history] = strdup(t_con->line);
-
-                                                               /* wrap history at TELNET_LINE_HISTORY_SIZE */
-                                                               t_con->next_history = (t_con->next_history + 1) %
-                                                                               TELNET_LINE_HISTORY_SIZE;
-
-                                                               /* current history line starts at the new entry */
-                                                               t_con->current_history =
-                                                                               t_con->next_history;
-
-                                                               free(t_con->history[t_con->current_history]);
-                                                               t_con->history[t_con->current_history] = strdup("");
-                                                       }
-
-                                                       t_con->line_size = 0;
-
-                                                       /* to suppress prompt in log callback during command execution */
-                                                       t_con->prompt_visible = false;
-
-                                                       if (strcmp(t_con->line, "shutdown") == 0)
-                                                               telnet_save_history(t_con);
-
-                                                       retval = command_run_line(command_context, t_con->line);
-
-                                                       t_con->line_cursor = 0;
-                                                       t_con->prompt_visible = true;
-
-                                                       if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
-                                                               return ERROR_SERVER_REMOTE_CLOSED;
-
-                                                       /* the prompt is always * placed at the line beginning */
-                                                       telnet_write(connection, "\r", 1);
-
-                                                       retval = telnet_prompt(connection);
-                                                       if (retval == ERROR_SERVER_REMOTE_CLOSED)
-                                                               return ERROR_SERVER_REMOTE_CLOSED;
-
+                                                       retval = telnet_exec_line(connection);
+                                                       if (retval != ERROR_OK)
+                                                               return retval;
                                                } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) {       /* delete character */
-                                                       if (t_con->line_cursor > 0) {
-                                                               if (t_con->line_cursor != t_con->line_size) {
-                                                                       size_t i;
-                                                                       telnet_write(connection, "\b", 1);
-                                                                       t_con->line_cursor--;
-                                                                       t_con->line_size--;
-                                                                       memmove(t_con->line + t_con->line_cursor,
-                                                                                       t_con->line + t_con->line_cursor + 1,
-                                                                                       t_con->line_size -
-                                                                                       t_con->line_cursor);
-
-                                                                       telnet_write(connection,
-                                                                                       t_con->line + t_con->line_cursor,
-                                                                                       t_con->line_size -
-                                                                                       t_con->line_cursor);
-                                                                       telnet_write(connection, " \b", 2);
-                                                                       for (i = t_con->line_cursor; i < t_con->line_size; i++)
-                                                                               telnet_write(connection, "\b", 1);
-                                                               } else {
-                                                                       t_con->line_size--;
-                                                                       t_con->line_cursor--;
-                                                                       /* back space: move the 'printer' head one char
-                                                                        * back, overwrite with space, move back again */
-                                                                       telnet_write(connection, "\b \b", 3);
-                                                               }
-                                                       }
+                                                       telnet_delete_character(connection);
                                                } else if (*buf_p == 0x15) {    /* clear line */
                                                        telnet_clear_line(connection, t_con);
                                                } else if (*buf_p == CTRL('B')) {       /* cursor left */
-                                                       if (t_con->line_cursor > 0) {
-                                                               telnet_write(connection, "\b", 1);
-                                                               t_con->line_cursor--;
-                                                       }
+                                                       telnet_move_cursor(connection, t_con->line_cursor - 1);
                                                        t_con->state = TELNET_STATE_DATA;
                                                } else if (*buf_p == CTRL('C')) {       /* interrupt */
-                                                       /* print '^C' at line end, and display a new command prompt */
-                                                       telnet_move_cursor(connection, t_con->line_size);
-                                                       telnet_write(connection, "^C\n\r", 4);
-                                                       t_con->line_cursor = 0;
-                                                       t_con->line_size = 0;
-                                                       telnet_prompt(connection);
+                                                       telnet_interrupt(connection);
                                                } else if (*buf_p == CTRL('F')) {       /* cursor right */
-                                                       if (t_con->line_cursor < t_con->line_size)
-                                                               telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
+                                                       telnet_move_cursor(connection, t_con->line_cursor + 1);
                                                        t_con->state = TELNET_STATE_DATA;
                                                } else if (*buf_p == CTRL('P')) {       /* cursor up */
                                                        telnet_history_up(connection);
@@ -742,15 +810,7 @@ static int telnet_input(struct connection *connection)
                                                } else if (*buf_p == CTRL('E')) {       /* move the cursor to the end of the line */
                                                        telnet_move_cursor(connection, t_con->line_size);
                                                } else if (*buf_p == CTRL('K')) {       /* kill line to end */
-                                                       if (t_con->line_cursor < t_con->line_size) {
-                                                               /* overwrite with space, until end of line, move back */
-                                                               for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
-                                                                       telnet_write(connection, " ", 1);
-                                                               for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
-                                                                       telnet_write(connection, "\b", 1);
-                                                               t_con->line[t_con->line_cursor] = '\0';
-                                                               t_con->line_size = t_con->line_cursor;
-                                                       }
+                                                       telnet_cut_line_to_end(connection);
                                                } else if (*buf_p == '\t') {
                                                        telnet_auto_complete(connection);
                                                } else {
@@ -788,15 +848,10 @@ static int telnet_input(struct connection *connection)
                        case TELNET_STATE_ESCAPE:
                                if (t_con->last_escape == '[') {
                                        if (*buf_p == 'D') {    /* cursor left */
-                                               if (t_con->line_cursor > 0) {
-                                                       telnet_write(connection, "\b", 1);
-                                                       t_con->line_cursor--;
-                                               }
+                                               telnet_move_cursor(connection, t_con->line_cursor - 1);
                                                t_con->state = TELNET_STATE_DATA;
                                        } else if (*buf_p == 'C') {     /* cursor right */
-                                               if (t_con->line_cursor < t_con->line_size)
-                                                       telnet_write(connection,
-                                                                       t_con->line + t_con->line_cursor++, 1);
+                                               telnet_move_cursor(connection, t_con->line_cursor + 1);
                                                t_con->state = TELNET_STATE_DATA;
                                        } else if (*buf_p == 'A') {     /* cursor up */
                                                telnet_history_up(connection);
@@ -816,25 +871,7 @@ static int telnet_input(struct connection *connection)
                                } else if (t_con->last_escape == '3') {
                                        /* Remove character */
                                        if (*buf_p == '~') {
-                                               if (t_con->line_cursor < t_con->line_size) {
-                                                       size_t i;
-                                                       t_con->line_size--;
-                                                       /* remove char from line buffer */
-                                                       memmove(t_con->line + t_con->line_cursor,
-                                                                       t_con->line + t_con->line_cursor + 1,
-                                                                       t_con->line_size - t_con->line_cursor);
-
-                                                       /* print remainder of buffer */
-                                                       telnet_write(connection, t_con->line + t_con->line_cursor,
-                                                                       t_con->line_size - t_con->line_cursor);
-                                                       /* overwrite last char with whitespace */
-                                                       telnet_write(connection, " \b", 2);
-
-                                                       /* move back to cursor position*/
-                                                       for (i = t_con->line_cursor; i < t_con->line_size; i++)
-                                                               telnet_write(connection, "\b", 1);
-                                               }
-
+                                               telnet_remove_character(connection);
                                                t_con->state = TELNET_STATE_DATA;
                                        } else
                                                t_con->state = TELNET_STATE_DATA;