[mem][linux]: add ExLinux on mem package and move VirtualMemoryEx info on it

mem/ex_linux.go

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//go:build linux
+
+package mem
+
+import (
+	"context"
+	"encoding/json"
+)
+
+type ExVirtualMemory struct {
+	ActiveFile   uint64 `json:"activefile"`
+	InactiveFile uint64 `json:"inactivefile"`
+	ActiveAnon   uint64 `json:"activeanon"`
+	InactiveAnon uint64 `json:"inactiveanon"`
+	Unevictable  uint64 `json:"unevictable"`
+}
+
+func (v ExVirtualMemory) String() string {
+	s, _ := json.Marshal(v)
+	return string(s)
+}
+
+type ExLinux struct{}
+
+func NewExLinux() *ExLinux {
+	return &ExLinux{}
+}
+
+func (ex *ExLinux) VirtualMemory() (*ExVirtualMemory, error) {
+	return ex.VirtualMemoryWithContext(context.Background())
+}
+
+func (ex *ExLinux) VirtualMemoryWithContext(ctx context.Context) (*ExVirtualMemory, error) {
+	_, vmEx, err := fillFromMeminfoWithContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return vmEx, nil
+}

mem/mem_linux.go

@@ -6,7 +6,6 @@ package mem
 import (
 	"bufio"
 	"context"
-	"encoding/json"
 	"fmt"
 	"io"
 	"math"
@@ -19,19 +18,6 @@ import (
 	"github.com/shirou/gopsutil/v4/internal/common"
 )
 
-type VirtualMemoryExStat struct {
-	ActiveFile   uint64 `json:"activefile"`
-	InactiveFile uint64 `json:"inactivefile"`
-	ActiveAnon   uint64 `json:"activeanon"`
-	InactiveAnon uint64 `json:"inactiveanon"`
-	Unevictable  uint64 `json:"unevictable"`
-}
-
-func (v VirtualMemoryExStat) String() string {
-	s, _ := json.Marshal(v)
-	return string(s)
-}
-
 func VirtualMemory() (*VirtualMemoryStat, error) {
 	return VirtualMemoryWithContext(context.Background())
 }
@@ -44,19 +30,7 @@ func VirtualMemoryWithContext(ctx context.Context) (*VirtualMemoryStat, error) {
 	return vm, nil
 }
 
-func VirtualMemoryEx() (*VirtualMemoryExStat, error) {
+func fillFromMeminfoWithContext(ctx context.Context) (*VirtualMemoryStat, *ExVirtualMemory, error) {
-	return VirtualMemoryExWithContext(context.Background())
-}
-
-func VirtualMemoryExWithContext(ctx context.Context) (*VirtualMemoryExStat, error) {
-	_, vmEx, err := fillFromMeminfoWithContext(ctx)
-	if err != nil {
-		return nil, err
-	}
-	return vmEx, nil
-}
-
-func fillFromMeminfoWithContext(ctx context.Context) (*VirtualMemoryStat, *VirtualMemoryExStat, error) {
 	filename := common.HostProcWithContext(ctx, "meminfo")
 	lines, _ := common.ReadLines(filename)
 
@@ -67,7 +41,7 @@ func fillFromMeminfoWithContext(ctx context.Context) (*VirtualMemoryStat, *Virtu
 	sReclaimable := false // "Sreclaimable:" not available: 2.6.19 / Nov 2006
 
 	ret := &VirtualMemoryStat{}
-	retEx := &VirtualMemoryExStat{}
+	retEx := &ExVirtualMemory{}
 
 	for _, line := range lines {
 		fields := strings.Split(line, ":")
@@ -409,7 +383,7 @@ func SwapMemoryWithContext(ctx context.Context) (*SwapMemoryStat, error) {
 // calculateAvailVmem is a fallback under kernel 3.14 where /proc/meminfo does not provide
 // "MemAvailable:" column. It reimplements an algorithm from the link below
 // https://github.com/giampaolo/psutil/pull/890
-func calculateAvailVmem(ctx context.Context, ret *VirtualMemoryStat, retEx *VirtualMemoryExStat) uint64 {
+func calculateAvailVmem(ctx context.Context, ret *VirtualMemoryStat, retEx *ExVirtualMemory) uint64 {
 	var watermarkLow uint64
 
 	fn := common.HostProcWithContext(ctx, "zoneinfo")

mem/mem_linux_test.go

@@ -13,8 +13,10 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestVirtualMemoryEx(t *testing.T) {
+func TestExVirtualMemory(t *testing.T) {
-	v, err := VirtualMemoryEx()
+	ex := NewExLinux()
+
+	v, err := ex.VirtualMemory()
 	if err != nil {
 		t.Error(err)
 	}