Use calculateTimeIdx to calculate array idx in LeapArray#getPreviousWindow (#723)

* also some code cleanup

sentinel-core/src/main/java/com/alibaba/csp/sentinel/node/StatisticNode.java

@@ -147,8 +147,7 @@ public class StatisticNode implements Node {
 
     @Override
     public long totalRequest() {
-        long totalRequest = rollingCounterInMinute.pass() + rollingCounterInMinute.block();
-        return totalRequest;
+        return rollingCounterInMinute.pass() + rollingCounterInMinute.block();
     }
 
     @Override

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/base/LeapArray.java

@@ -209,8 +209,7 @@ public abstract class LeapArray<T> {
         if (timeMillis < 0) {
             return null;
         }
-        long timeId = (timeMillis - windowLengthInMs) / windowLengthInMs;
-        int idx = (int)(timeId % array.length());
+        int idx = calculateTimeIdx(timeMillis - windowLengthInMs);
         timeMillis = timeMillis - windowLengthInMs;
         WindowWrap<T> wrap = array.get(idx);
 

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/statistic/metric/ArrayMetric.java

@@ -234,8 +234,8 @@ public class ArrayMetric implements Metric {
 
     @Override
     public long previousWindowBlock() {
-        WindowWrap<MetricBucket> wrap = data.currentWindow();
-        wrap = data.getPreviousWindow();
+        data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.getPreviousWindow();
         if (wrap == null) {
             return 0;
         }
@@ -244,8 +244,8 @@ public class ArrayMetric implements Metric {
 
     @Override
     public long previousWindowPass() {
-        WindowWrap<MetricBucket> wrap = data.currentWindow();
-        wrap = data.getPreviousWindow();
+        data.currentWindow();
+        WindowWrap<MetricBucket> wrap = data.getPreviousWindow();
         if (wrap == null) {
             return 0;
         }