Remove unnecessary allocation

Change-Id: If77b7b37ae736fdf21f4c337350905480e6fb011
Signed-off-by: Vladimir Lavor <vlavor@cisco.com>

4 files changed, 51 insertions, 52 deletions

diff --git a/adapter/statsclient/stat_segment_api.go b/adapter/statsclient/stat_segment_api.go
index f2e4219..0ca0c8b 100644
--- a/adapter/statsclient/stat_segment_api.go
+++ b/adapter/statsclient/stat_segment_api.go
@@ -55,8 +55,8 @@ type statDirectoryName []byte
 // statSegment represents common API for every stats API version
 type statSegment interface {
 	// GetDirectoryVector returns pointer to memory where the beginning
-	// of the data directory is located
-	GetDirectoryVector() (unsafe.Pointer, error)
+	// of the data directory is located.
+	GetDirectoryVector() unsafe.Pointer
 
 	// GetStatDirOnIndex accepts directory vector and particular index.
 	// Returns pointer to the beginning of the segment. Also the directory
diff --git a/adapter/statsclient/statsclient.go b/adapter/statsclient/statsclient.go
index 9c1c334..a39cbd5 100644
--- a/adapter/statsclient/statsclient.go
+++ b/adapter/statsclient/statsclient.go
@@ -138,8 +138,8 @@ func (sc *StatsClient) ListStats(patterns ...string) ([]string, error) {
 		return nil, err
 	}
 
-	dirVector, err := sc.GetDirectoryVector()
-	if err != nil {
+	dirVector := sc.GetDirectoryVector()
+	if dirVector == nil {
 		return nil, fmt.Errorf("failed to list stats: %v", err)
 	}
 	vecLen := *(*uint32)(vectorLen(dirVector))
@@ -171,8 +171,8 @@ func (sc *StatsClient) DumpStats(patterns ...string) (entries []adapter.StatEntr
 		return nil, err
 	}
 
-	dirVector, err := sc.GetDirectoryVector()
-	if err != nil {
+	dirVector := sc.GetDirectoryVector()
+	if dirVector == nil {
 		return nil, err
 	}
 	dirLen := *(*uint32)(vectorLen(dirVector))
@@ -217,8 +217,8 @@ func (sc *StatsClient) PrepareDir(patterns ...string) (*adapter.StatDir, error)
 	}
 	dir.Indexes = indexes
 
-	dirVector, err := sc.GetDirectoryVector()
-	if err != nil {
+	dirVector := sc.GetDirectoryVector()
+	if dirVector == nil {
 		return nil, err
 	}
 	dirLen := *(*uint32)(vectorLen(dirVector))
@@ -263,8 +263,8 @@ func (sc *StatsClient) UpdateDir(dir *adapter.StatDir) (err error) {
 		return adapter.ErrStatsAccessFailed
 	}
 
-	dirVector, err := sc.GetDirectoryVector()
-	if err != nil {
+	dirVector := sc.GetDirectoryVector()
+	if dirVector == nil {
 		return err
 	}
 	for i, index := range dir.Indexes {
@@ -412,8 +412,8 @@ func (sc *StatsClient) listIndexesFunc(f func(name []byte) bool) (indexes []uint
 		indexes = make([]uint32, 0, 3200)
 	}
 
-	dirVector, err := sc.GetDirectoryVector()
-	if err != nil {
+	dirVector := sc.GetDirectoryVector()
+	if dirVector == nil {
 		return nil, err
 	}
 	vecLen := *(*uint32)(vectorLen(dirVector))
diff --git a/adapter/statsclient/statseg_v1.go b/adapter/statsclient/statseg_v1.go
index a02c7ac..3d45201 100644
--- a/adapter/statsclient/statseg_v1.go
+++ b/adapter/statsclient/statseg_v1.go
@@ -66,9 +66,9 @@ func (ss *statSegmentV1) loadSharedHeader(b []byte) (header sharedHeaderV1) {
 	}
 }
 
-func (ss *statSegmentV1) GetDirectoryVector() (unsafe.Pointer, error) {
+func (ss *statSegmentV1) GetDirectoryVector() unsafe.Pointer {
 	dirOffset, _, _ := ss.getOffsets()
-	return unsafe.Pointer(&ss.sharedHeader[dirOffset]), nil
+	return unsafe.Pointer(&ss.sharedHeader[dirOffset])
 }
 
 func (ss *statSegmentV1) GetErrorVector() (unsafe.Pointer, error) {
diff --git a/adapter/statsclient/statseg_v2.go b/adapter/statsclient/statseg_v2.go
index 7091ff9..d52077f 100644
--- a/adapter/statsclient/statseg_v2.go
+++ b/adapter/statsclient/statseg_v2.go
@@ -15,7 +15,6 @@
 package statsclient
 
 import (
-	"fmt"
 	"sync/atomic"
 	"unsafe"
 
@@ -65,7 +64,7 @@ func (ss *statSegmentV2) loadSharedHeader(b []byte) (header sharedHeaderV2) {
 	}
 }
 
-func (ss *statSegmentV2) GetDirectoryVector() (unsafe.Pointer, error) {
+func (ss *statSegmentV2) GetDirectoryVector() unsafe.Pointer {
 	header := ss.loadSharedHeader(ss.sharedHeader)
 	return ss.adjust(unsafe.Pointer(&header.dirVector))
 }
@@ -100,8 +99,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		return adapter.ScalarStat(dirEntry.unionData)
 
 	case statDirErrorIndex:
-		dirVector, err := ss.getErrorVector()
-		if err != nil {
+		dirVector := ss.getErrorVector()
+		if dirVector == nil {
 			debugf("error vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -109,8 +108,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		var errData adapter.Counter
 		for i := uint32(0); i < vecLen; i++ {
 			cb := statSegPointer(dirVector, uintptr(i+1)*unsafe.Sizeof(uint64(0)))
-			cbVal, err := ss.adjust(vectorLen(cb))
-			if err != nil {
+			cbVal := ss.adjust(vectorLen(cb))
+			if cbVal == nil {
 				debugf("error counter pointer out of range")
 				continue
 			}
@@ -121,8 +120,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		return adapter.ErrorStat(errData)
 
 	case statDirCounterVectorSimple:
-		dirVector, err := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
-		if err != nil {
+		dirVector := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
+		if dirVector == nil {
 			debugf("data vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -130,8 +129,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		data := make([][]adapter.Counter, vecLen)
 		for i := uint32(0); i < vecLen; i++ {
 			counterVectorOffset := statSegPointer(dirVector, uintptr(i+1)*unsafe.Sizeof(uint64(0)))
-			counterVector, err := ss.adjust(vectorLen(counterVectorOffset))
-			if err != nil {
+			counterVector := ss.adjust(vectorLen(counterVectorOffset))
+			if counterVector == nil {
 				debugf("counter (vector simple) pointer out of range")
 				continue
 			}
@@ -146,8 +145,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		return adapter.SimpleCounterStat(data)
 
 	case statDirCounterVectorCombined:
-		dirVector, err := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
-		if err != nil {
+		dirVector := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
+		if dirVector == nil {
 			debugf("data vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -155,8 +154,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		data := make([][]adapter.CombinedCounter, vecLen)
 		for i := uint32(0); i < vecLen; i++ {
 			counterVectorOffset := statSegPointer(dirVector, uintptr(i+1)*unsafe.Sizeof(uint64(0)))
-			counterVector, err := ss.adjust(vectorLen(counterVectorOffset))
-			if err != nil {
+			counterVector := ss.adjust(vectorLen(counterVectorOffset))
+			if counterVector == nil {
 				debugf("counter (vector combined) pointer out of range")
 				continue
 			}
@@ -171,8 +170,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 		return adapter.CombinedCounterStat(data)
 
 	case statDirNameVector:
-		dirVector, err := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
-		if err != nil {
+		dirVector := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
+		if dirVector == nil {
 			debugf("data vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -184,8 +183,8 @@ func (ss *statSegmentV2) CopyEntryData(statSegDir unsafe.Pointer) adapter.Stat {
 				debugf("name vector out of range for %s (%v)", dirEntry.name, i)
 				continue
 			}
-			nameVector, err := ss.adjust(vectorLen(nameVectorOffset))
-			if err != nil {
+			nameVector := ss.adjust(vectorLen(nameVectorOffset))
+			if nameVector == nil {
 				debugf("name data pointer out of range")
 				continue
 			}
@@ -219,8 +218,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		*stat = adapter.ScalarStat(dirEntry.unionData)
 
 	case adapter.ErrorStat:
-		dirVector, err := ss.getErrorVector()
-		if err != nil {
+		dirVector := ss.getErrorVector()
+		if dirVector == nil {
 			debugf("error vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -228,8 +227,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		var errData adapter.Counter
 		for i := uint32(0); i < vecLen; i++ {
 			cb := statSegPointer(dirVector, uintptr(i+1)*unsafe.Sizeof(uint64(0)))
-			cbVal, err := ss.adjust(vectorLen(cb))
-			if err != nil {
+			cbVal := ss.adjust(vectorLen(cb))
+			if cbVal == nil {
 				debugf("error counter pointer out of range")
 				continue
 			}
@@ -240,8 +239,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		*stat = adapter.ErrorStat(errData)
 
 	case adapter.SimpleCounterStat:
-		dirVector, err := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
-		if err != nil {
+		dirVector := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
+		if dirVector == nil {
 			debugf("data vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -252,8 +251,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		}
 		for i := uint32(0); i < vecLen; i++ {
 			counterVectorOffset := statSegPointer(dirVector, uintptr(i+1)*unsafe.Sizeof(uint64(0)))
-			counterVector, err := ss.adjust(vectorLen(counterVectorOffset))
-			if err != nil {
+			counterVector := ss.adjust(vectorLen(counterVectorOffset))
+			if counterVector == nil {
 				debugf("counter (vector simple) pointer out of range")
 				continue
 			}
@@ -267,8 +266,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		}
 
 	case adapter.CombinedCounterStat:
-		dirVector, err := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
-		if err != nil {
+		dirVector := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
+		if dirVector == nil {
 			debugf("data vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -276,8 +275,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		data := (*stat).(adapter.CombinedCounterStat)
 		for i := uint32(0); i < vecLen; i++ {
 			counterVectorOffset := statSegPointer(dirVector, uintptr(i+1)*unsafe.Sizeof(uint64(0)))
-			counterVector, err := ss.adjust(vectorLen(counterVectorOffset))
-			if err != nil {
+			counterVector := ss.adjust(vectorLen(counterVectorOffset))
+			if counterVector == nil {
 				debugf("counter (vector combined) pointer out of range")
 				continue
 			}
@@ -291,8 +290,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 		}
 
 	case adapter.NameStat:
-		dirVector, err := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
-		if err != nil {
+		dirVector := ss.adjust(unsafe.Pointer(&dirEntry.unionData))
+		if dirVector == nil {
 			debugf("data vector pointer is out of range for %s", dirEntry.name)
 			return nil
 		}
@@ -304,8 +303,8 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 				debugf("name vector out of range for %s (%v)", dirEntry.name, i)
 				continue
 			}
-			nameVector, err := ss.adjust(vectorLen(nameVectorOffset))
-			if err != nil {
+			nameVector := ss.adjust(vectorLen(nameVectorOffset))
+			if nameVector == nil {
 				debugf("name data pointer out of range")
 				continue
 			}
@@ -334,18 +333,18 @@ func (ss *statSegmentV2) UpdateEntryData(statSegDir unsafe.Pointer, stat *adapte
 
 // Adjust data pointer using shared header and base and return
 // the pointer to a data segment
-func (ss *statSegmentV2) adjust(data unsafe.Pointer) (unsafe.Pointer, error) {
+func (ss *statSegmentV2) adjust(data unsafe.Pointer) unsafe.Pointer {
 	header := ss.loadSharedHeader(ss.sharedHeader)
 	adjusted := unsafe.Pointer(uintptr(unsafe.Pointer(&ss.sharedHeader[0])) +
 		uintptr(*(*uint64)(data)) - uintptr(*(*uint64)(unsafe.Pointer(&header.base))))
 	if uintptr(unsafe.Pointer(&ss.sharedHeader[len(ss.sharedHeader)-1])) <= uintptr(adjusted) ||
 		uintptr(unsafe.Pointer(&ss.sharedHeader[0])) >= uintptr(adjusted) {
-		return nil, fmt.Errorf("adjusted data out of range for %v", data)
+		return nil
 	}
-	return adjusted, nil
+	return adjusted
 }
 
-func (ss *statSegmentV2) getErrorVector() (unsafe.Pointer, error) {
+func (ss *statSegmentV2) getErrorVector() unsafe.Pointer {
 	header := ss.loadSharedHeader(ss.sharedHeader)
 	return ss.adjust(unsafe.Pointer(&header.errorVector))
 }