Rename config module to settings

components/settings/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+  SRCS "settings.c"
+  INCLUDE_DIRS "."
+  REQUIRES fatal nvs_flash
+)

components/settings/settings.c

@@ -0,0 +1,250 @@
+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#include "settings.h"
+
+#include "fatal.h"
+
+#include "esp_log.h"
+#include "nvs_flash.h"
+#include <stdbool.h>
+#include <string.h>
+
+#define TAG "Settings"
+
+#define NAMESPACE "settings"
+#define MAX_CALLBACKS 8
+
+typedef enum {
+	HOSTNAME,
+	SSID,
+	PSK,
+	TIMEZONE,
+	ITEM_COUNT,
+} ItemIndex;
+
+typedef struct {
+	const char *id;
+	const char *default_value;
+	char value[SETTINGS_MAX_VALUE_SIZE];
+	struct {
+		SettingsCallback funcs[MAX_CALLBACKS];
+		unsigned count;
+	} callbacks;
+} Item;
+
+static Item state[ITEM_COUNT] = {
+	[HOSTNAME] = {
+	    .id = "hostname",
+	    .default_value = CONFIG_DEFAULT_HOSTNAME,
+	},
+	[SSID] = {
+		.id = "ssid",
+		.default_value = CONFIG_DEFAULT_SSID,
+	},
+	[PSK] = {
+		.id = "psk",
+		.default_value = CONFIG_DEFAULT_PSK,
+	},
+	[TIMEZONE] = {
+		.id = "timezone",
+		.default_value = CONFIG_DEFAULT_TIMEZONE,
+	},
+};
+
+static bool load(ItemIndex item)
+{
+	esp_err_t error;
+
+	nvs_handle_t handle;
+	error = nvs_open(NAMESPACE, NVS_READONLY, &handle);
+	if (error == ESP_ERR_NVS_NOT_FOUND)
+		return false;
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error opening NVS: %04x", error);
+		return false;
+	}
+
+	size_t size = SETTINGS_MAX_VALUE_SIZE;
+	error = nvs_get_str(handle, state[item].id, state[item].value, &size);
+	if (error == ESP_ERR_NVS_NOT_FOUND) {
+		nvs_close(handle);
+		return false;
+	} else if (error != ESP_OK) {
+		ESP_LOGE(
+		    TAG, "Error loading %s from storage: %04x", state[item].id,
+		    error);
+		nvs_close(handle);
+		return false;
+	}
+
+	nvs_close(handle);
+	return true;
+}
+
+static void save(ItemIndex item)
+{
+	esp_err_t error;
+
+	nvs_handle_t handle;
+	error = nvs_open(NAMESPACE, NVS_READWRITE, &handle);
+	if (error == ESP_ERR_NVS_NOT_FOUND)
+		return;
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error opening NVS: %04x", error);
+		return;
+	}
+
+	error = nvs_set_str(handle, state[item].id, state[item].value);
+	if (error != ESP_OK) {
+		ESP_LOGE(
+		    TAG, "Error loading %s from storage: %04x", state[item].id,
+		    error);
+		nvs_close(handle);
+		return;
+	}
+
+	error = nvs_commit(handle);
+	if (error != ESP_OK)
+		ESP_LOGE(TAG, "Error commiting NVS update: %04x", error);
+
+	nvs_close(handle);
+}
+
+static void set(ItemIndex item, const char *value)
+{
+	if (value == NULL) {
+		ESP_LOGW(
+		    TAG, "Attempt to set %s to null pointer; ignored",
+		    state[item].id);
+		return;
+	}
+
+	size_t len = strlen(value);
+	if (len >= SETTINGS_MAX_VALUE_SIZE) {
+		ESP_LOGW(
+		    TAG, "%s value \"%s\" exceeds maximum size; truncated",
+		    state[item].id, value);
+		len = SETTINGS_MAX_VALUE_SIZE - 1;
+	}
+
+	memcpy(state[item].value, value, len);
+	state[item].value[len] = '\0';
+
+	save(item);
+	for (unsigned i = 0; i < state[item].callbacks.count; ++i)
+		state[item].callbacks.funcs[i](state[item].value);
+}
+
+static size_t get(ItemIndex item, char *buffer, size_t buffer_size)
+{
+	size_t len = strlen(state[item].value);
+	if (len < buffer_size) {
+		memcpy(buffer, state[item].value, len);
+		buffer[len] = '\0';
+	}
+	return len;
+}
+
+static void add_callback(ItemIndex item, SettingsCallback callback)
+{
+	if (callback == NULL) {
+		ESP_LOGW(
+		    TAG, "Attempt to add null callback for %s; ignored",
+		    state[item].id);
+	} else if (state[item].callbacks.count >= MAX_CALLBACKS) {
+		ESP_LOGE(
+		    TAG, "Max callbacks exceeded for %s; callback discarded",
+		    state[item].id);
+	} else {
+		const unsigned pos = state[item].callbacks.count;
+		state[item].callbacks.funcs[pos] = callback;
+		++state[item].callbacks.count;
+	}
+}
+
+void settings_init()
+{
+	esp_err_t error;
+
+	error = nvs_flash_init();
+	if (error == ESP_ERR_NVS_NO_FREE_PAGES
+	    || error == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+		ESP_LOGI(TAG, "NVS partition full or outdated; erasing");
+		(void)nvs_flash_erase();
+		error = nvs_flash_init();
+	}
+	if (error != ESP_OK) {
+		ESP_LOGE(TAG, "Error initializing NVS store: %04x", error);
+		FATAL();
+	}
+
+	for (ItemIndex item = (ItemIndex)0; item < ITEM_COUNT; ++item) {
+		if (!load(item)) {
+			set(item, state[item].default_value);
+			save(item);
+		}
+	}
+}
+
+void settings_set_hostname(const char *hostname)
+{
+	set(HOSTNAME, hostname);
+}
+
+size_t settings_get_hostname(char *buffer, size_t buffer_size)
+{
+	return get(HOSTNAME, buffer, buffer_size);
+}
+
+void settings_add_hostname_callback(SettingsCallback callback)
+{
+	add_callback(HOSTNAME, callback);
+}
+
+void settings_set_ssid(const char *ssid)
+{
+	set(SSID, ssid);
+}
+
+size_t settings_get_ssid(char *buffer, size_t buffer_size)
+{
+	return get(SSID, buffer, buffer_size);
+}
+
+void settings_add_ssid_callback(SettingsCallback callback)
+{
+	add_callback(SSID, callback);
+}
+
+void settings_set_psk(const char *psk)
+{
+	set(PSK, psk);
+}
+
+size_t settings_get_psk(char *buffer, size_t buffer_size)
+{
+	return get(PSK, buffer, buffer_size);
+}
+
+void settings_add_psk_callback(SettingsCallback callback)
+{
+	add_callback(PSK, callback);
+}
+
+void settings_set_timezone(const char *timezone)
+{
+	set(TIMEZONE, timezone);
+}
+
+size_t settings_get_timezone(char *buffer, size_t buffer_size)
+{
+	return get(TIMEZONE, buffer, buffer_size);
+}
+
+void settings_add_timezone_callback(SettingsCallback callback)
+{
+	add_callback(TIMEZONE, callback);
+}

components/settings/settings.h

@@ -0,0 +1,139 @@
+/*
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Copyright (c) Camden Dixie O'Brien
+ */
+
+#ifndef SETTINGS_H
+#define SETTINGS_H
+
+#include <stddef.h>
+
+#define SETTINGS_MAX_VALUE_SIZE 32U
+
+/**
+ * Callback type for settings updates
+ */
+typedef void (*SettingsCallback)(const char *value);
+
+/**
+ * Initialize the settings module.
+ *
+ * If there are saved settings, they will be loaded. Otherwise,
+ * the default settings will be loaded and saved.
+ */
+void settings_init(void);
+
+/**
+ * Set the device's hostname.
+ *
+ * The argument should be a null-terminated string. If the maximum
+ * length is exceeded, the value will still be used, but will be
+ * truncated.
+ */
+void settings_set_hostname(const char *hostname);
+
+/**
+ * Write the device's hostname into the given buffer.
+ *
+ * The length of the hostname is returned. If the value's size exceeds
+ * the size of the buffer, nothing will be written to the buffer but
+ * the length is still returned.
+ */
+size_t settings_get_hostname(char *buffer, size_t buffer_size);
+
+/**
+ * Add a callback for hostname updates.
+ *
+ * The function specified in the argument will be invoked whenever
+ * the hostname is updated, with the new value as its argument. The
+ * lifetime of the passed argument will be static, but the value may
+ * be modified once the callback returns.
+ */
+void settings_add_hostname_callback(SettingsCallback callback);
+
+/**
+ * Set the SSID of the WiFi network.
+ *
+ * The argument should be a null-terminated string. If the maximum
+ * length is exceeded, the value will still be used, but will be
+ * truncated.
+ */
+void settings_set_ssid(const char *ssid);
+
+/**
+ * Write the SSID of the WiFi network into the given buffer.
+ *
+ * The length of the SSID is returned. If the value's size exceeds
+ * the size of the buffer, nothing will be written to the buffer but
+ * the length is still returned.
+ */
+size_t settings_get_ssid(char *buffer, size_t buffer_size);
+
+/**
+ * Add a callback for SSID updates.
+ *
+ * The function specified in the argument will be invoked whenever
+ * the SSID is updated, with the new value as its argument. The
+ * lifetime of the passed argument will be static, but the value may
+ * be modified once the callback returns.
+ */
+void settings_add_ssid_callback(SettingsCallback callback);
+
+/**
+ * Set the PSK for the WiFi network.
+ *
+ * The argument should be a null-terminated string. If the maximum
+ * length is exceeded, the value will still be used, but will be
+ * truncated.
+ */
+void settings_set_psk(const char *psk);
+
+/**
+ * Write the PSK for the WiFi network into the given buffer.
+ *
+ * The length of the psk is returned. If the value's size exceeds
+ * the size of the buffer, nothing will be written to the buffer but
+ * the length is still returned.
+ */
+size_t settings_get_psk(char *buffer, size_t buffer_size);
+
+/**
+ * Add a callback for PSK updates.
+ *
+ * The function specified in the argument will be invoked whenever the
+ * PSK is updated, with the new value as its argument. The lifetime of
+ * the passed argument will be static, but the value may be modified
+ * once the callback returns.
+ */
+void settings_add_psk_callback(SettingsCallback callback);
+
+/**
+ * Set the timezone.
+ *
+ * The argument should be a null-terminated string, containing a
+ * timezone spec in the format expected by tzset(). If the maximum
+ * length is exceeded, the value will still be used, but will be
+ * truncated.
+ */
+void settings_set_timezone(const char *psk);
+
+/**
+ * Write the timezone into the given buffer.
+ *
+ * The length of the timezone is returned. If the value's size exceeds
+ * the size of the buffer, nothing will be written to the buffer but
+ * the length is still returned.
+ */
+size_t settings_get_timezone(char *buffer, size_t buffer_size);
+
+/**
+ * Add a callback for timezone updates.
+ *
+ * The function specified in the argument will be invoked whenever the
+ * timezone is updated, with the new value as its argument. The
+ * lifetime of the passed argument will be static, but the value may
+ * be modified once the callback returns.
+ */
+void settings_add_timezone_callback(SettingsCallback callback);
+
+#endif