updated with opencode

go.mod

@@ -9,5 +9,5 @@ require (
 	github.com/tklauser/go-sysconf v0.3.11 // indirect
 	github.com/tklauser/numcpus v0.6.0 // indirect
 	github.com/yusufpapurcu/wmi v1.2.2 // indirect
-	golang.org/x/sys v0.4.0 // indirect
+	golang.org/x/sys v0.4.0
 )

main_windows.go

@@ -1,55 +1,79 @@
 package main
 
-/*
-#include <windows.h>
-BOOL SetPriority(DWORD pid, int priority) {
-    HANDLE h = OpenProcess(PROCESS_ALL_ACCESS, 0, pid);
-    if (!h) return FALSE;
-    BOOL success = SetPriorityClass(h, priority);
-    CloseHandle(h);
-    return success;
-}
-*/
-import "C"
 import (
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"time"
+
 	"github.com/postfinance/single"
 	"github.com/shirou/gopsutil/process"
-	"os"
-	"runtime"
-	"syscall"
-	"time"
-	"unsafe"
+	"golang.org/x/sys/windows"
 )
 
-func MessageBox(lpText string, lpCaption string, uType int) int {
-	var convertedCaption, _ = syscall.UTF16PtrFromString(lpCaption)
-	var convertedTitle, _ = syscall.UTF16PtrFromString(lpText)
-	returnCode, _, _ := syscall.NewLazyDLL("user32.dll").NewProc("MessageBoxW").Call(
-		uintptr(0),
-		uintptr(unsafe.Pointer(convertedCaption)),
-		uintptr(unsafe.Pointer(convertedTitle)),
-		uintptr(uType),
+const (
+	memThreshold   = 512 * 1024 * 1024
+	selfPriority   = windows.IDLE_PRIORITY_CLASS
+	targetPriority = windows.HIGH_PRIORITY_CLASS
 )
-	return int(returnCode)
+
+func setPriority(pid int32, class uint32) error {
+	h, err := windows.OpenProcess(windows.PROCESS_SET_INFORMATION, false, uint32(pid))
+	if err != nil {
+		return fmt.Errorf("open process %d: %w", pid, err)
+	}
+	defer windows.CloseHandle(h)
+	return windows.SetPriorityClass(h, class)
 }
-
-var lockFile, _ = single.New("autoPriority")
 
 func main() {
-	if err := lockFile.Lock(); err != nil {
-		MessageBox("The program is already running", "Only one instance of the program can be run\nYou can close it via the Task Manager", 48)
+	lock, err := single.New("autoPriority")
+	if err != nil {
+		log.Fatalf("create lock: %v", err)
+	}
+	if err := lock.Lock(); err != nil {
+		windows.MessageBox(0,
+			windows.StringToUTF16Ptr("The program is already running.\nYou can close it via the Task Manager."),
+			windows.StringToUTF16Ptr("autoPriority"),
+			windows.MB_OK|windows.MB_ICONWARNING,
+		)
 		os.Exit(1)
 	}
+	defer lock.Unlock()
 
-	C.SetPriority(C.DWORD(os.Getpid()), 0x00000040)
-	for range time.Tick(time.Minute) {
-		processes, _ := process.Processes()
-		for _, proc := range processes {
-			memoryInfo, err := proc.MemoryInfo()
-			if err == nil && memoryInfo.RSS >= (0.5*1024*1024*1024) {
-				C.SetPriority(C.DWORD(proc.Pid), 0x00000080)
+	if err := setPriority(int32(os.Getpid()), selfPriority); err != nil {
+		log.Printf("set self priority: %v", err)
+	}
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, os.Interrupt)
+
+	tk := time.NewTicker(time.Minute)
+	defer tk.Stop()
+
+	for {
+		select {
+		case <-sig:
+			log.Println("exit")
+			return
+		case <-tk.C:
+			procs, err := process.Processes()
+			if err != nil {
+				log.Printf("list processes: %v", err)
+				continue
+			}
+			for _, p := range procs {
+				m, err := p.MemoryInfo()
+				if err != nil {
+					continue
+				}
+				if m.RSS >= memThreshold {
+					if err := setPriority(p.Pid, targetPriority); err != nil {
+						log.Printf("PID %d: %v", p.Pid, err)
+					}
+				}
 			}
 		}
-		runtime.GC()
 	}
 }