Refactored GetProcessMemoryInfo to return VM_COUNTERS

This change allows the function to return the process memory info
directly instead of copying the result of the underlying Nt function.

Author: xEgoist

lib/std/child_process.zig

@@ -112,7 +112,7 @@ pub const ChildProcess = struct {
 
         const rusage_init = switch (builtin.os.tag) {
             .linux => @as(?std.os.rusage, null),
-            .windows => @as(?windows.PROCESS_MEMORY_COUNTERS, null),
+            .windows => @as(?windows.VM_COUNTERS, null),
             else => {},
         };
     };
@@ -374,9 +374,7 @@ pub const ChildProcess = struct {
         });
 
         if (self.request_resource_usage_statistics) {
-            var pmc: windows.PROCESS_MEMORY_COUNTERS = undefined;
-            try windows.GetProcessMemoryInfo(self.id, &pmc);
-            self.resource_usage_statistics.rusage = pmc;
+            self.resource_usage_statistics.rusage = try windows.GetProcessMemoryInfo(self.id);
         }
 
         os.close(self.id);

lib/std/os/windows.zig

@@ -3994,24 +3994,11 @@ pub const GetProcessMemoryInfoError = error{
     Unexpected,
 };
 
-pub fn GetProcessMemoryInfo(hProcess: HANDLE, out: *PROCESS_MEMORY_COUNTERS) GetProcessMemoryInfoError!void {
+pub fn GetProcessMemoryInfo(hProcess: HANDLE) GetProcessMemoryInfoError!VM_COUNTERS {
     var vmc: VM_COUNTERS = undefined;
     const rc = ntdll.NtQueryInformationProcess(hProcess, .ProcessVmCounters, &vmc, @sizeOf(VM_COUNTERS), null);
     switch (rc) {
-        .SUCCESS => {
-            out.* = PROCESS_MEMORY_COUNTERS{
-                .cb = @sizeOf(PROCESS_MEMORY_COUNTERS),
-                .PageFaultCount = vmc.PageFaultCount,
-                .PeakWorkingSetSize = vmc.PeakWorkingSetSize,
-                .WorkingSetSize = vmc.WorkingSetSize,
-                .QuotaPeakPagedPoolUsage = vmc.QuotaPeakPagedPoolUsage,
-                .QuotaPagedPoolUsage = vmc.QuotaPagedPoolUsage,
-                .QuotaPeakNonPagedPoolUsage = vmc.QuotaPeakNonPagedPoolUsage,
-                .QuotaNonPagedPoolUsage = vmc.QuotaNonPagedPoolUsage,
-                .PagefileUsage = vmc.PagefileUsage,
-                .PeakPagefileUsage = vmc.PeakPagefileUsage,
-            };
-        },
+        .SUCCESS => return vmc,
         .ACCESS_DENIED => return error.AccessDenied,
         .INVALID_HANDLE => return error.InvalidHandle,
         .INVALID_PARAMETER => unreachable,