shell: Extend shell as a log backend

Initial logger backend support added to shell.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

subsys/shell/shell_log_backend.c

@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) 2018 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <shell/shell_log_backend.h>
+#include <shell/shell.h>
+#include "shell_ops.h"
+#include <logging/log_ctrl.h>
+
+int shell_log_backend_output_func(u8_t *data, size_t length, void *ctx)
+{
+	shell_print_stream(ctx, data, length);
+	return length;
+}
+
+void shell_log_backend_enable(const struct shell_log_backend *backend,
+			      void *ctx, u32_t init_log_level)
+{
+	log_backend_enable(backend->backend, ctx, init_log_level);
+	log_output_ctx_set(backend->log_output, ctx);
+	backend->control_block->cnt = 0;
+	backend->control_block->state = SHELL_LOG_BACKEND_ENABLED;
+}
+
+static struct log_msg *msg_from_fifo(const struct shell_log_backend *backend)
+{
+	struct log_msg *msg = k_fifo_get(backend->fifo, K_NO_WAIT);
+
+	if (msg) {
+		atomic_dec(&backend->control_block->cnt);
+	}
+
+	return msg;
+}
+
+static void fifo_flush(const struct shell_log_backend *backend)
+{
+	struct log_msg *msg = msg_from_fifo(backend);
+
+	/* Flush log messages. */
+	while (msg) {
+		log_msg_put(msg);
+		msg = msg_from_fifo(backend);
+	}
+}
+
+static void msg_to_fifo(const struct shell *shell,
+			struct log_msg *msg)
+{
+	atomic_val_t cnt;
+
+	k_fifo_put(shell->log_backend->fifo, msg);
+
+	cnt = atomic_inc(&shell->log_backend->control_block->cnt);
+
+	/* If there is too much queued free the oldest one. */
+	if (cnt >= CONFIG_SHELL_MAX_LOG_MSG_BUFFERED) {
+		log_msg_put(msg_from_fifo(shell->log_backend));
+		if (IS_ENABLED(CONFIG_SHELL_STATS)) {
+			shell->stats->log_lost_cnt++;
+		}
+	}
+}
+
+void shell_log_backend_disable(const struct shell_log_backend *backend)
+{
+	fifo_flush(backend);
+	log_backend_disable(backend->backend);
+	backend->control_block->state = SHELL_LOG_BACKEND_DISABLED;
+}
+
+static void msg_process(const struct log_output *log_output,
+			struct log_msg *msg)
+{
+	u32_t flags = 0;
+
+	if (IS_ENABLED(CONFIG_SHELL)) {
+		flags |= LOG_OUTPUT_FLAG_COLORS;
+	}
+
+	if (IS_ENABLED(CONFIG_SHELL)) {
+		flags |= LOG_OUTPUT_FLAG_FORMAT_TIMESTAMP;
+	}
+
+	log_output_msg_process(log_output, msg, flags);
+	log_msg_put(msg);
+}
+
+bool shell_log_backend_process(const struct shell_log_backend *backend)
+{
+	const struct shell *shell =
+			(const struct shell *)backend->backend->cb->ctx;
+	struct log_msg *msg = msg_from_fifo(backend);
+
+	if (!msg) {
+		return false;
+	}
+
+	msg_process(shell->log_backend->log_output, msg);
+
+	return true;
+}
+
+static void put(const struct log_backend *const backend, struct log_msg *msg)
+{
+	const struct shell *shell = (const struct shell *)backend->cb->ctx;
+	struct k_poll_signal *signal;
+
+	log_msg_get(msg);
+
+	switch (shell->log_backend->control_block->state) {
+	case SHELL_LOG_BACKEND_ENABLED:
+		msg_to_fifo(shell, msg);
+
+		if (IS_ENABLED(CONFIG_MULTITHREADING)) {
+			signal = &shell->ctx->signals[SHELL_SIGNAL_LOG_MSG];
+			k_poll_signal(signal, 0);
+		}
+
+		break;
+
+	case SHELL_LOG_BACKEND_PANIC:
+		msg_process(shell->log_backend->log_output, msg);
+		break;
+
+	case SHELL_LOG_BACKEND_DISABLED:
+		/* fall through */
+		/* no break */
+	default:
+		/* Discard message. */
+		log_msg_put(msg);
+	}
+}
+
+static void panic(const struct log_backend *const backend)
+{
+	const struct shell *shell = (const struct shell *)backend->cb->ctx;
+	int err;
+
+	err = shell->iface->api->enable(shell->iface, true);
+
+	if (err == 0) {
+		shell->log_backend->control_block->state =
+							SHELL_LOG_BACKEND_PANIC;
+
+		/* Move to the start of next line. */
+		shell_multiline_data_calc(&shell->ctx->vt100_ctx.cons,
+						  shell->ctx->cmd_buff_pos,
+						  shell->ctx->cmd_buff_len);
+		shell_op_cursor_vert_move(shell, -1);
+		shell_op_cursor_horiz_move(shell,
+					   -shell->ctx->vt100_ctx.cons.cur_x);
+
+		while (shell_log_backend_process(shell->log_backend)) {
+			/* empty */
+		}
+	} else {
+		shell_log_backend_disable(shell->log_backend);
+	}
+}
+
+const struct log_backend_api log_backend_shell_api = {
+	.put = put,
+	.panic = panic
+};