filter/count: Fix alignment on 32-bit systems.

filter/count/count.go

Index: filter/count/count.go
diff --git a/filter/count/count.go b/filter/count/count.go
index a5478868128be9bcbb3d29e476ffe816e4f14bf6..9206ddcff5cc55a0a16d9eab87a1877cde5e876b 100644
--- a/filter/count/count.go
+++ b/filter/count/count.go
@@ -9,19 +9,41 @@
 package count
 
 import (
+	"fmt"
 	"sync/atomic"
 )
 
+type Counter struct {
+	value int64
+}
+
+func (c *Counter) increment() {
+	atomic.AddInt64(&c.value, 1)

[iannucci, 2015/08/22 01:00:56]

as discussed offline, let's just change the current implementation to use 32bit
atomics, since they don't have the alignment bug/requirement.

+}
+
+func (c *Counter) Get() int64 {
+	return atomic.LoadInt64(&c.value)
+}
+
 // Entry is a success/fail pair for a single API method. It's returned
 // by the Counter interface.
 type Entry struct {
-	Successes int64
-	Errors    int64
+	Successes *Counter
+	Errors    *Counter
+}
+
+func (e *Entry) init() {
+	e.Successes = &Counter{}
+	e.Errors = &Counter{}
+}
+
+func (e *Entry) String() string {
+	return fmt.Sprintf("{Successes:%d, Errors:%d}", e.Successes.Get(), e.Errors.Get())
 }
 
 // Total is a convenience function for getting the total number of calls to
 // this API. It's Successes+Errors.
-func (e Entry) Total() int64 { return e.Successes + e.Errors }
+func (e *Entry) Total() int64 { return e.Successes.Get() + e.Errors.Get() }
 
 func (e *Entry) up(errs ...error) error {
 	err := error(nil)
@@ -29,9 +51,9 @@ func (e *Entry) up(errs ...error) error {
 		err = errs[0]
 	}
 	if err == nil {
-		atomic.AddInt64(&e.Successes, 1)
+		e.Successes.increment()
 	} else {
-		atomic.AddInt64(&e.Errors, 1)
+		e.Errors.increment()
 	}
 	return err
 }