Always update 'values' member of DiskIOMeter

Always update the `values` member during the call of
DiskIOMeter_updateValues().

This makes the values of every instance of DiskIOMeter consistent.
The user might see non-zero bars (or graph) during the "stale" status
of the meter after this commit. The side effect is not a bug.

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>

1 files changed, 44 insertions, 37 deletions

diff --git a/DiskIOMeter.c b/DiskIOMeter.c
index b69fb40b..6662918b 100644
--- a/DiskIOMeter.c
+++ b/DiskIOMeter.c
@@ -36,16 +36,13 @@ static void DiskIOMeter_updateValues(Meter* this) {
 
    static uint64_t cached_last_update;
    uint64_t passedTimeInMs = host->realtimeMs - cached_last_update;
+   bool hasNewData = false;
+   DiskIOData data;
 
    /* update only every 500ms to have a sane span for rate calculation */
    if (passedTimeInMs > 500) {
-      static uint64_t cached_read_total;
-      static uint64_t cached_write_total;
-      static uint64_t cached_msTimeSpend_total;
-      uint64_t diff;
-
-      DiskIOData data;
-      if (!Platform_getDiskIO(&data)) {
+      hasNewData = Platform_getDiskIO(&data);
+      if (!hasNewData) {
          status = RATESTATUS_NODATA;
       } else if (cached_last_update == 0) {
          status = RATESTATUS_INIT;
@@ -56,42 +53,54 @@ static void DiskIOMeter_updateValues(Meter* this) {
       }
 
       cached_last_update = host->realtimeMs;
+   }
 
-      if (status == RATESTATUS_NODATA) {
-         xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "no data");
-         return;
-      }
+   if (hasNewData) {
+      static uint64_t cached_read_total;
+      static uint64_t cached_write_total;
+      static uint64_t cached_msTimeSpend_total;
 
-      if (data.totalBytesRead > cached_read_total) {
-         diff = data.totalBytesRead - cached_read_total;
-         diff = (1000 * diff) / passedTimeInMs; /* convert to B/s */
-         diff /= ONE_K; /* convert to KiB/s */
-         cached_read_diff = (uint32_t)diff;
-      } else {
-         cached_read_diff = 0;
+      if (status != RATESTATUS_INIT) {
+         uint64_t diff;
+
+         if (data.totalBytesRead > cached_read_total) {
+            diff = data.totalBytesRead - cached_read_total;
+            diff = (1000 * diff) / passedTimeInMs; /* convert to B/s */
+            diff /= ONE_K; /* convert to KiB/s */
+            cached_read_diff = (uint32_t)diff;
+         } else {
+            cached_read_diff = 0;
+         }
+
+         if (data.totalBytesWritten > cached_write_total) {
+            diff = data.totalBytesWritten - cached_write_total;
+            diff = (1000 * diff) / passedTimeInMs; /* convert to B/s */
+            diff /= ONE_K; /* convert to KiB/s */
+            cached_write_diff = (uint32_t)diff;
+         } else {
+            cached_write_diff = 0;
+         }
+
+         if (data.totalMsTimeSpend > cached_msTimeSpend_total) {
+            diff = data.totalMsTimeSpend - cached_msTimeSpend_total;
+            cached_utilisation_diff = 100.0 * (double)diff / passedTimeInMs;
+            cached_utilisation_diff = MINIMUM(cached_utilisation_diff, 100.0);
+         } else {
+            cached_utilisation_diff = 0.0;
+         }
       }
-      cached_read_total = data.totalBytesRead;
 
-      if (data.totalBytesWritten > cached_write_total) {
-         diff = data.totalBytesWritten - cached_write_total;
-         diff = (1000 * diff) / passedTimeInMs; /* convert to B/s */
-         diff /= ONE_K; /* convert to KiB/s */
-         cached_write_diff = (uint32_t)diff;
-      } else {
-         cached_write_diff = 0;
-      }
+      cached_read_total = data.totalBytesRead;
       cached_write_total = data.totalBytesWritten;
-
-      if (data.totalMsTimeSpend > cached_msTimeSpend_total) {
-         diff = data.totalMsTimeSpend - cached_msTimeSpend_total;
-         cached_utilisation_diff = 100.0 * (double)diff / passedTimeInMs;
-         cached_utilisation_diff = MINIMUM(cached_utilisation_diff, 100.0);
-      } else {
-         cached_utilisation_diff = 0.0;
-      }
       cached_msTimeSpend_total = data.totalMsTimeSpend;
    }
 
+   this->values[0] = cached_utilisation_diff;
+
+   if (status == RATESTATUS_NODATA) {
+      xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "no data");
+      return;
+   }
    if (status == RATESTATUS_INIT) {
       xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "init");
       return;
@@ -101,8 +110,6 @@ static void DiskIOMeter_updateValues(Meter* this) {
       return;
    }
 
-   this->values[0] = cached_utilisation_diff;
-
    char bufferRead[12], bufferWrite[12];
    Meter_humanUnit(bufferRead, cached_read_diff, sizeof(bufferRead));
    Meter_humanUnit(bufferWrite, cached_write_diff, sizeof(bufferWrite));