reduce use of unsafe.Pointer in wingui

Author: apmckinlay

builtin/dll_wingui.go

@@ -13,7 +13,6 @@ import (
 	"unsafe"
 
 	. "github.com/apmckinlay/gsuneido/core"
-	"github.com/apmckinlay/gsuneido/util/hacks"
 	"golang.org/x/exp/constraints"
 	"golang.org/x/sys/windows"
 )
@@ -147,31 +146,17 @@ func bufZstr(buf []byte) SuStr {
 	return SuStr(string(buf))
 }
 
-// ptrZstr copies a nul terminated string from an unsafe.Pointer.
+// ptrZstr copies a nul terminated string from *byte.
 // If nul is not found, then the entire length is returned.
-func ptrZstr(p unsafe.Pointer, n int) Value {
+func ptrZstr(p *byte, n int) Value {
 	if p == nil || n == 0 {
 		return False
 	}
-	srcSlice := unsafe.Slice((*byte)(p), n)
-	i := slices.Index(srcSlice, 0)
-	if i == -1 {
-		i = n // No null terminator found, use entire length
+	src := unsafe.Slice(p, n)
+	if i := slices.Index(src, 0); i >= 0 {
+		src = src[:i]
 	}
-	buf := make([]byte, i)
-	copy(buf, srcSlice[:i])
-	return SuStr(hacks.BStoS(buf))
-}
-
-// ptrNstr copies a string of a given length from an unsafe.Pointer
-func ptrNstr(p unsafe.Pointer, n uintptr) Value {
-	if p == nil || n == 0 {
-		return EmptyStr
-	}
-	buf := make([]byte, n)
-	srcSlice := unsafe.Slice((*byte)(p), n)
-	copy(buf, srcSlice)
-	return SuStr(hacks.BStoS(buf))
+	return SuStr(string(src))
 }
 
 // getZstrBs copies the string into the byte slice and adds a nul terminator.

builtin/kernel_wingui.go

@@ -85,9 +85,9 @@ func GlobalAlloc(a, b Value) Value {
 // dll Kernel32:GlobalLock(pointer handle) pointer
 var globalLock = kernel32.MustFindProc("GlobalLock").Addr()
 
-func globallock(handle HANDLE) unsafe.Pointer {
+func globallock(handle HANDLE) uintptr {
 	rtn, _, _ := syscall.SyscallN(globalLock, handle)
-	return unsafe.Pointer(rtn) //nolint
+	return rtn
 }
 
 var _ = builtin(GlobalLock, "(hMem)")
@@ -116,12 +116,13 @@ var _ = builtin(GlobalAllocData, "(s)")
 
 func GlobalAllocData(a Value) Value {
 	s := ToStr(a)
-	handle := globalalloc(GMEM_MOVEABLE, uintptr(len(s)))
-	if len(s) > 0 {
+	n := len(s)
+	handle := globalalloc(GMEM_MOVEABLE, uintptr(n))
+	if n > 0 {
 		p := globallock(handle)
-		assert.That(p != nil)
+		assert.That(p != 0)
 		defer globalunlock(handle)
-		dstSlice := unsafe.Slice((*byte)(p), len(s))
+		dstSlice := unsafe.Slice((*byte)(unsafe.Pointer(p)), n) //nolint
 		copy(dstSlice, s)
 	}
 	return intRet(handle) // caller must GlobalFree
@@ -136,9 +137,10 @@ func GlobalData(a Value) Value {
 		return EmptyStr
 	}
 	p := globallock(hm)
-	assert.That(p != nil)
+	assert.That(p != 0)
 	defer globalunlock(hm)
-	return ptrNstr(p, n)
+	buf := unsafe.Slice((*byte)(unsafe.Pointer(p)), n) //nolint
+	return SuStr(string(buf))
 }
 
 // dll Kernel32:GlobalUnlock(pointer handle) bool

builtin/sendmsg_wingui.go

@@ -357,8 +357,7 @@ func SendMessageHditem(a, b, c, d Value) Value {
 		uintptr(unsafe.Pointer(&hdi)))
 	fromHdItem(&hdi, d)
 	if cchTextMaxGiven {
-		d.Put(nil, SuStr("pszText"),
-			ptrZstr(unsafe.Pointer(hdi.pszText), int(cchTextMax)))
+		d.Put(nil, SuStr("pszText"), ptrZstr(hdi.pszText, int(cchTextMax)))
 		ToContainer(d).Delete(nil, SuStr("cchTextMax"))
 		runtime.KeepAlive(hdi.pszText)
 	}

builtin/struct_wingui.go

@@ -142,7 +142,8 @@ func (*suRect) updateStruct(ob Value, p unsafe.Pointer) {
 
 func rect(_ *Thread, args []Value) Value {
 	r := toRect(args[0])
-	return ptrNstr(unsafe.Pointer(r), nRect)
+	buf := unsafe.Slice((*byte)(unsafe.Pointer(r)), nRect)
+	return SuStr(hacks.BStoS(buf))
 }
 
 //-------------------------------------------------------------------
@@ -226,8 +227,7 @@ func NMTVDISPINFO(a Value) Value {
 	ob := fromNMHdr(&di.nmhdr)
 	ob.Put(nil, SuStr("nmhdr"), fromNMHdr(&di.nmhdr))
 	tvi := fromTVItem(&di.item)
-	pszText := unsafe.Pointer(di.item.pszText)
-	tvi.Put(nil, SuStr("pszText"), ptrZstr(pszText, 1024))
+	tvi.Put(nil, SuStr("pszText"), ptrZstr(di.item.pszText, 1024))
 	ob.Put(nil, SuStr("item"), tvi)
 	return ob
 }
@@ -475,7 +475,7 @@ type stSCNotification struct {
 	ch                   int32
 	modifiers            int32
 	modificationType     int32
-	text                 uintptr
+	text                 *byte
 	length               int
 	linesAdded           int
 	message              int32
@@ -514,7 +514,7 @@ func SCNotificationText(a Value) Value {
 	}
 	scn := (*stSCNotification)(toptr(adr))
 	ob := fromSCNotification(scn)
-	ob.Put(nil, SuStr("text"), ptrZstr(toptr(scn.text), 1024))
+	ob.Put(nil, SuStr("text"), ptrZstr(scn.text, 1024))
 	return ob
 }
 
@@ -759,11 +759,12 @@ var _ = Global.Builtin("BITMAPINFOHEADER",
 
 func bmih(_ *Thread, args []Value) Value {
 	bmih := toBitMapInfoHeader(args[0])
-	return ptrNstr(unsafe.Pointer(&bmih), nBitMapInfoHeader)
+	buf := unsafe.Slice((*byte)(unsafe.Pointer(bmih)), nBitMapInfoHeader)
+	return SuStr(hacks.BStoS(buf))
 }
 
-func toBitMapInfoHeader(hdr Value) stBitMapInfoHeader {
-	return stBitMapInfoHeader{
+func toBitMapInfoHeader(hdr Value) *stBitMapInfoHeader {
+	return &stBitMapInfoHeader{
 		biSize:          int32(nBitMapInfoHeader),
 		biWidth:         getInt32(hdr, "biWidth"),
 		biHeight:        getInt32(hdr, "biHeight"),