subsys : shell : Added API changing prompt

1. Added API to change shell prompt in runtime.
2. Added prompt buffer length configuration in Kconfig.

Signed-off-by: Jakub Rzeszutko <jakub.rzeszutko@nordicsemi.no>

include/shell/shell.h

@@ -349,7 +349,7 @@ extern const struct log_backend_api log_backend_shell_api;
  * @brief Shell instance internals.
  */
 struct shell {
-	const char *const name; /*!< Terminal name. */
+	char *const prompt; /*!< shell prompt. */
 
 	const struct shell_transport *iface; /*!< Transport interface.*/
 	struct shell_ctx *ctx; /*!< Internal context.*/
@@ -375,16 +375,17 @@ struct shell {
  * @brief Macro for defining a shell instance.
  *
  * @param[in] _name             Instance name.
- * @param[in] shell_prefix      Shell prefix string.
+ * @param[in] _prompt           Shell prompt string.
  * @param[in] transport_iface   Pointer to the transport interface.
  * @param[in] newline_ch        New line character - only allowed values are
  *				'\\n' or '\\r'.
  * @param[in] log_queue_size    Logger processing queue size.
  */
-#define SHELL_DEFINE(_name, shell_prefix, transport_iface,		     \
+#define SHELL_DEFINE(_name, _prompt, transport_iface,			     \
 		  newline_ch, log_queue_size)				     \
 	static const struct shell _name;				     \
 	static struct shell_ctx UTIL_CAT(_name, _ctx);			     \
+	static char _name##prompt[CONFIG_SHELL_PROMPT_LENGTH + 1] = _prompt; \
 	static u8_t _name##_out_buffer[CONFIG_SHELL_PRINTF_BUFF_SIZE];	     \
 	SHELL_LOG_BACKEND_DEFINE(_name, _name##_out_buffer,		     \
 					 CONFIG_SHELL_PRINTF_BUFF_SIZE);     \
@@ -397,7 +398,7 @@ struct shell {
 	static K_THREAD_STACK_DEFINE(_name##_stack, CONFIG_SHELL_STACK_SIZE);\
 	static struct k_thread _name##_thread;				     \
 	static const struct shell _name = {				     \
-		.name = shell_prefix,					     \
+		.prompt = _name##prompt,				     \
 		.iface = transport_iface,				     \
 		.ctx = &UTIL_CAT(_name, _ctx),				     \
 		.history = SHELL_HISTORY_PTR(_name),			     \
@@ -528,6 +529,17 @@ static inline bool shell_help_requested(const struct shell *shell)
 void shell_help_print(const struct shell *shell,
 		      const struct shell_getopt_option *opt, size_t opt_len);
 
+/*
+ * @brief Change displayed shell prompt.
+ *
+ * @param[in] shell	Pointer to the shell instance.
+ * @param[in] prompt	New shell prompt.
+ *
+ * @return 0		success
+ * @return -1		new string is too long
+ */
+int shell_prompt_change(const struct shell *shell, char *prompt);
+
 /*
  * @brief Prints help if request and prints error message on wrong argument
  *	  count.

subsys/shell/Kconfig

@@ -67,6 +67,12 @@ config SHELL_BACKSPACE_MODE_DELETE
 	  Some terminals send code: 0x08 (backspace) other 0x7F (delete). When
 	  this option is set shell will expect 0x7F for backspace key.
 
+config SHELL_PROMPT_LENGTH
+	int "Maximum prompt length"
+	default 16
+	help
+	  Maximum length of prompt name in bytes.
+
 config SHELL_CMD_BUFF_SIZE
 	int "Shell command buffer size"
 	default 256

subsys/shell/shell.c

@@ -234,7 +234,7 @@ static void shell_state_set(const struct shell *shell, enum shell_state state)
 
 	if (state == SHELL_STATE_ACTIVE) {
 		shell_cmd_buffer_clear(shell);
-		shell_fprintf(shell, SHELL_INFO, "%s", shell->name);
+		shell_fprintf(shell, SHELL_INFO, "%s", shell->prompt);
 	}
 }
 
@@ -598,7 +598,7 @@ static void tab_options_print(const struct shell *shell,
 		idx++;
 	}
 
-	shell_fprintf(shell, SHELL_INFO, "\r\n%s", shell->name);
+	shell_fprintf(shell, SHELL_INFO, "\r\n%s", shell->prompt);
 	shell_fprintf(shell, SHELL_NORMAL, "%s", shell->ctx->cmd_buff);
 
 	shell_op_cursor_position_synchronize(shell);
@@ -718,7 +718,7 @@ static void metakeys_handle(const struct shell *shell, char data)
 	case SHELL_VT100_ASCII_CTRL_L: /* CTRL + L */
 		SHELL_VT100_CMD(shell, SHELL_VT100_CURSORHOME);
 		SHELL_VT100_CMD(shell, SHELL_VT100_CLEARSCREEN);
-		shell_fprintf(shell, SHELL_INFO, "%s", shell->name);
+		shell_fprintf(shell, SHELL_INFO, "%s", shell->prompt);
 		if (flag_echo_is_set(shell)) {
 			shell_fprintf(shell, SHELL_NORMAL, "%s",
 				      shell->ctx->cmd_buff);
@@ -1116,7 +1116,7 @@ static void shell_current_command_erase(const struct shell *shell)
 
 static void shell_current_command_print(const struct shell *shell)
 {
-	shell_fprintf(shell, SHELL_INFO, "%s", shell->name);
+	shell_fprintf(shell, SHELL_INFO, "%s", shell->prompt);
 
 	if (flag_echo_is_set(shell)) {
 		shell_fprintf(shell, SHELL_NORMAL, "%s", shell->ctx->cmd_buff);
@@ -1145,7 +1145,7 @@ static int shell_instance_init(const struct shell *shell, const void *p_config,
 			       bool use_colors)
 {
 	assert(shell);
-	assert(shell->ctx && shell->iface && shell->name);
+	assert(shell->ctx && shell->iface && shell->prompt);
 	assert((shell->newline_char == '\n') || (shell->newline_char == '\r'));
 
 	int err;
@@ -1174,7 +1174,7 @@ static int shell_instance_init(const struct shell *shell, const void *p_config,
 	shell->ctx->state = SHELL_STATE_INITIALIZED;
 	shell->ctx->vt100_ctx.cons.terminal_wid = SHELL_DEFAULT_TERMINAL_WIDTH;
 	shell->ctx->vt100_ctx.cons.terminal_hei = SHELL_DEFAULT_TERMINAL_HEIGHT;
-	shell->ctx->vt100_ctx.cons.name_len = shell_strlen(shell->name);
+	shell->ctx->vt100_ctx.cons.name_len = shell_strlen(shell->prompt);
 	shell->ctx->internal.flags.use_colors =
 					IS_ENABLED(CONFIG_SHELL_VT100_COLORS);
 
@@ -1268,7 +1268,7 @@ int shell_init(const struct shell *shell, const void *transport_config,
 static int shell_instance_uninit(const struct shell *shell)
 {
 	assert(shell);
-	assert(shell->ctx && shell->iface && shell->name);
+	assert(shell->ctx && shell->iface && shell->prompt);
 	int err;
 
 	if (flag_processing_is_set(shell)) {
@@ -1307,7 +1307,7 @@ int shell_uninit(const struct shell *shell)
 int shell_start(const struct shell *shell)
 {
 	assert(shell);
-	assert(shell->ctx && shell->iface && shell->name);
+	assert(shell->ctx && shell->iface && shell->prompt);
 	int err;
 
 	if (shell->ctx->state != SHELL_STATE_INITIALIZED) {
@@ -1663,6 +1663,21 @@ void shell_help_print(const struct shell *shell,
 	help_subcmd_print(shell);
 }
 
+int shell_prompt_change(const struct shell *shell, char *prompt)
+{
+
+	size_t len = shell_strlen(prompt);
+
+	assert(shell);
+	assert(prompt);
+
+	if (len <= CONFIG_SHELL_PROMPT_LENGTH) {
+		memcpy(shell->prompt, prompt, len + 1); /* +1 for '\0' */
+		return 0;
+	}
+	return -1;
+}
+
 bool shell_cmd_precheck(const struct shell *shell,
 			bool arg_cnt_ok,
 			const struct shell_getopt_option *opt,

subsys/shell/shell_ops.c

@@ -29,14 +29,14 @@ void shell_op_cursor_horiz_move(const struct shell *shell, s32_t delta)
  */
 static inline bool full_line_cmd(const struct shell *shell)
 {
-	return ((shell->ctx->cmd_buff_len + shell_strlen(shell->name))
+	return ((shell->ctx->cmd_buff_len + shell_strlen(shell->prompt))
 			% shell->ctx->vt100_ctx.cons.terminal_wid == 0);
 }
 
 /* Function returns true if cursor is at beginning of an empty line. */
 bool shell_cursor_in_empty_line(const struct shell *shell)
 {
-	return ((shell->ctx->cmd_buff_pos + shell_strlen(shell->name))
+	return ((shell->ctx->cmd_buff_pos + shell_strlen(shell->prompt))
 			% shell->ctx->vt100_ctx.cons.terminal_wid == 0);
 }