Avoid using wall time in case it jumps. (#3)

Instead, use std::chrono's steady_clock.

esphome/components/emporia_vue_utility/emporia_vue_utility.cpp

@@ -24,27 +24,17 @@ void EmporiaVueUtility::update() {
 }
 
 void EmporiaVueUtility::loop() {
-  static const time_t delayed_start_time =
-      ::time(nullptr) + INITIAL_STARTUP_DELAY;
-  static time_t next_expected_meter_request = 0;
-  static time_t next_meter_join = delayed_start_time + METER_REJOIN_INTERVAL;
-  static time_t next_version_request = 0;
+  static const steady_time_point delayed_start_time =
+    steady_clock::now() + INITIAL_STARTUP_DELAY;
+  static steady_time_point next_expected_meter_request = min_steady_time_point;
+  static steady_time_point next_meter_join = delayed_start_time + METER_REJOIN_INTERVAL;
+  static steady_time_point next_version_request = min_steady_time_point;
   static uint8_t startup_step = 0;
   char msg_type = 0;
   size_t msg_len = 0;
 
   msg_len = read_msg();
-  now = ::time(nullptr);
-
-  /* sanity checks! */
-  if (next_expected_meter_request >
-      now + (INITIAL_STARTUP_DELAY + METER_REJOIN_INTERVAL)) {
-    ESP_LOGD(TAG, "Time jumped back (%lld > %lld + %lld); resetting",
-             (long long)next_expected_meter_request, (long long)now,
-             (long long)(INITIAL_STARTUP_DELAY + METER_REJOIN_INTERVAL));
-    next_meter_join = 0;
-    next_expected_meter_request = now + update_interval_;
-  }
+  now = steady_clock::now();
 
   if (msg_len != 0) {
     msg_type = input_buffer.data[2];
@@ -52,7 +42,7 @@ void EmporiaVueUtility::loop() {
     switch (msg_type) {
       case 'r':  // Meter reading
         led_link(true);
-        if (now < last_meter_reading + int(update_interval_ / 4)) {
+        if (now < (last_meter_reading + update_interval_ / 4)) {
           // Sometimes a duplicate message is sent in quick succession.
           // Ignoring the duplicate.
           ESP_LOGD(TAG, "Got extra message %lds after the previous message.",
@@ -159,4 +149,4 @@ void EmporiaVueUtility::dump_config() {
   LOG_UPDATE_INTERVAL(this);
 }
 }  // namespace emporia_vue_utility
-}  // namespace esphome
+}  // namespace esphome

esphome/components/emporia_vue_utility/emporia_vue_utility.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <chrono>
+
 #include "driver/gpio.h"
 
 #include "esphome/components/sensor/sensor.h"
@@ -24,13 +26,13 @@
 
 // How often to attempt to re-join the meter when it hasn't
 // been returning readings
-#define METER_REJOIN_INTERVAL 30
+#define METER_REJOIN_INTERVAL std::chrono::seconds(30)
 
 // How often to attempt to re-request the MGM firmware version.
-#define MGM_FIRMWARE_REQUEST_INTERVAL 3
+#define MGM_FIRMWARE_REQUEST_INTERVAL std::chrono::seconds(3)
 
 // On first startup, how long before trying to start to talk to meter
-#define INITIAL_STARTUP_DELAY 10
+#define INITIAL_STARTUP_DELAY std::chrono::seconds(10)
 
 // Should this code manage the "wifi" and "link" LEDs?
 // set to false if you want manually manage them elsewhere
@@ -126,9 +128,14 @@ class EmporiaVueUtility : public PollingComponent, public uart::UARTDevice {
   uint16_t pos = 0;
   uint16_t data_len;
 
-  time_t last_meter_reading = 0;
+  using steady_time_point = std::chrono::time_point<std::chrono::steady_clock>;
+  static constexpr steady_time_point min_steady_time_point =
+    steady_time_point::min();
+  using steady_clock = std::chrono::steady_clock;
+
+  steady_time_point last_meter_reading = min_steady_time_point;
   bool last_reading_has_error;
-  time_t now;
+  steady_time_point now;
 
   // The most recent meter divisor, meter reading payload V2 byte 47
   uint8_t meter_div = 0;
@@ -139,7 +146,7 @@ class EmporiaVueUtility : public PollingComponent, public uart::UARTDevice {
   void set_debug(bool enable) { debug_ = enable; }
   void set_update_interval(uint32_t update_interval) {
     PollingComponent::set_update_interval(update_interval);
-    update_interval_ = update_interval / 1000;
+    update_interval_ = std::chrono::milliseconds(update_interval);
   }
   void set_power_sensor(sensor::Sensor *sensor) { power_sensor_ = sensor; }
   void set_power_export_sensor(sensor::Sensor *sensor) {
@@ -311,7 +318,7 @@ class EmporiaVueUtility : public PollingComponent, public uart::UARTDevice {
 
       // Extra debugging of non-zero bytes, only on first packet or if
       // debug_ is true
-      if ((debug_) || (last_meter_reading == 0)) {
+      if ((debug_) || (last_meter_reading == min_steady_time_point)) {
         ESP_LOGD(TAG, "Meter Divisor: %d", meter_div);
         ESP_LOGD(TAG, "Meter Cost Unit: %d", cost_unit);
         ESP_LOGD(TAG, "Meter Flags: %02x %02x", mr2->maybe_flags[0],
@@ -356,7 +363,7 @@ class EmporiaVueUtility : public PollingComponent, public uart::UARTDevice {
 
       // Extra debugging of non-zero bytes, only on first packet or if
       // debug_ is true
-      if ((debug_) || (last_meter_reading == 0)) {
+      if ((debug_) || (last_meter_reading == min_steady_time_point)) {
         ESP_LOGD(TAG, "Meter Cost Unit: %d", cost_unit);
         ESP_LOGD(TAG, "Meter Divisor: %d", meter_div);
         ESP_LOGD(TAG, "Meter Energy Import Flags: %08x", mr7->import_wh);
@@ -777,7 +784,7 @@ class EmporiaVueUtility : public PollingComponent, public uart::UARTDevice {
 
  private:
   bool debug_ = false;
-  uint32_t update_interval_;
+  steady_clock::duration update_interval_;
   sensor::Sensor *power_sensor_{nullptr};
   sensor::Sensor *power_export_sensor_{nullptr};
   sensor::Sensor *power_import_sensor_{nullptr};
@@ -788,4 +795,4 @@ class EmporiaVueUtility : public PollingComponent, public uart::UARTDevice {
 };
 
 }  // namespace emporia_vue_utility
-}  // namespace esphome
+}  // namespace esphome