Converted most metrics to non-wmi

Signed-off-by: Ben Ridley <benridley29@gmail.com>

headers/psapi/psapi.go

@@ -0,0 +1,98 @@
+package psapi
+
+import (
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+// LPPerformanceInformation is a wrapper of the PERFORMANCE_INFORMATION struct.
+// https://docs.microsoft.com/en-us/windows/win32/api/psapi/ns-psapi-performance_information
+type LPPerformanceInformation struct {
+	cb                uint32
+	CommitTotal       *uint32
+	CommitLimit       *uint32
+	CommitPeak        *uint32
+	PhysicalTotal     *uint32
+	PhysicalAvailable *uint32
+	SystemCache       *uint32
+	KernelTotal       *uint32
+	KernelPaged       *uint32
+	KernelNonpaged    *uint32
+	PageSize          *uint32
+	HandleCount       uint32
+	ProcessCount      uint32
+	ThreadCount       uint32
+}
+
+// PerformanceInformation is a dereferenced version of LPPerformanceInformation
+type PerformanceInformation struct {
+	cb                uint32
+	CommitTotal       uint32
+	CommitLimit       uint32
+	CommitPeak        uint32
+	PhysicalTotal     uint32
+	PhysicalAvailable uint32
+	SystemCache       uint32
+	KernelTotal       uint32
+	KernelPaged       uint32
+	KernelNonpaged    uint32
+	PageSize          uint32
+	HandleCount       uint32
+	ProcessCount      uint32
+	ThreadCount       uint32
+}
+
+var (
+	psapi                  = windows.NewLazySystemDLL("psapi.dll")
+	procGetPerformanceInfo = psapi.NewProc("GetPerformanceInfo")
+)
+
+// GetLPPerformanceInfo retrieves the performance values contained in the LPPerformanceInformation structure.
+// https://docs.microsoft.com/en-us/windows/win32/api/psapi/nf-psapi-getperformanceinfo
+func GetLPPerformanceInfo() (LPPerformanceInformation, error) {
+	var pi LPPerformanceInformation
+	size := (uint32)(unsafe.Sizeof(pi))
+	pi.cb = size
+	pPi := uintptr(unsafe.Pointer(&pi))
+	r1, _, err := procGetPerformanceInfo.Call(pPi, uintptr(size))
+
+	if ret := *(*bool)(unsafe.Pointer(&r1)); ret == false {
+		// returned false
+		return LPPerformanceInformation{}, err
+	}
+
+	return pi, nil
+}
+
+// GetPerformanceInfo returns the dereferenced version of GetLPPerformanceInfo.
+func GetPerformanceInfo() (PerformanceInformation, error) {
+	var lppi LPPerformanceInformation
+	size := (uint32)(unsafe.Sizeof(lppi))
+	lppi.cb = size
+	pLppi := uintptr(unsafe.Pointer(&lppi))
+	r1, _, err := procGetPerformanceInfo.Call(pLppi, uintptr(size))
+
+	if ret := *(*bool)(unsafe.Pointer(&r1)); ret == false {
+		// returned false
+		return PerformanceInformation{}, err
+	}
+
+	var pi PerformanceInformation
+	pi.cb = lppi.cb
+	pi.CommitTotal = *(*uint32)(unsafe.Pointer(&lppi.CommitTotal))
+	pi.CommitLimit = *(*uint32)(unsafe.Pointer(&lppi.CommitLimit))
+	pi.CommitPeak = *(*uint32)(unsafe.Pointer(&lppi.CommitPeak))
+	pi.PhysicalTotal = *(*uint32)(unsafe.Pointer(&lppi.PhysicalTotal))
+	pi.PhysicalAvailable = *(*uint32)(unsafe.Pointer(&lppi.PhysicalAvailable))
+	pi.SystemCache = *(*uint32)(unsafe.Pointer(&lppi.SystemCache))
+	pi.KernelTotal = *(*uint32)(unsafe.Pointer(&lppi.KernelTotal))
+	pi.KernelPaged = *(*uint32)(unsafe.Pointer(&lppi.KernelPaged))
+	pi.KernelNonpaged = *(*uint32)(unsafe.Pointer(&lppi.KernelNonpaged))
+	pi.PageSize = *(*uint32)(unsafe.Pointer(&lppi.PageSize))
+	pi.HandleCount = lppi.HandleCount
+	pi.ProcessCount = lppi.ProcessCount
+	pi.ThreadCount = lppi.ThreadCount
+
+	return pi, nil
+}