1 files changed, 280 insertions, 0 deletions
diff --git a/src/syscall/dll_windows.go b/src/syscall/dll_windows.go
new file mode 100644
index 000000000..18663b486
--- /dev/null
+++ b/src/syscall/dll_windows.go
@@ -0,0 +1,280 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package syscall
+
+import (
+	"sync"
+	"sync/atomic"
+	"unsafe"
+)
+
+// DLLError describes reasons for DLL load failures.
+type DLLError struct {
+	Err     error
+	ObjName string
+	Msg     string
+}
+
+func (e *DLLError) Error() string { return e.Msg }
+
+// Implemented in ../runtime/syscall_windows.go.
+func Syscall(trap, nargs, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
+func Syscall6(trap, nargs, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
+func Syscall9(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)
+func Syscall12(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12 uintptr) (r1, r2 uintptr, err Errno)
+func Syscall15(trap, nargs, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2 uintptr, err Errno)
+func loadlibrary(filename *uint16) (handle uintptr, err Errno)
+func getprocaddress(handle uintptr, procname *uint8) (proc uintptr, err Errno)
+
+// A DLL implements access to a single DLL.
+type DLL struct {
+	Name   string
+	Handle Handle
+}
+
+// LoadDLL loads DLL file into memory.
+func LoadDLL(name string) (dll *DLL, err error) {
+	namep, err := UTF16PtrFromString(name)
+	if err != nil {
+		return nil, err
+	}
+	h, e := loadlibrary(namep)
+	if e != 0 {
+		return nil, &DLLError{
+			Err:     e,
+			ObjName: name,
+			Msg:     "Failed to load " + name + ": " + e.Error(),
+		}
+	}
+	d := &DLL{
+		Name:   name,
+		Handle: Handle(h),
+	}
+	return d, nil
+}
+
+// MustLoadDLL is like LoadDLL but panics if load operation failes.
+func MustLoadDLL(name string) *DLL {
+	d, e := LoadDLL(name)
+	if e != nil {
+		panic(e)
+	}
+	return d
+}
+
+// FindProc searches DLL d for procedure named name and returns *Proc
+// if found. It returns an error if search fails.
+func (d *DLL) FindProc(name string) (proc *Proc, err error) {
+	namep, err := BytePtrFromString(name)
+	if err != nil {
+		return nil, err
+	}
+	a, e := getprocaddress(uintptr(d.Handle), namep)
+	use(unsafe.Pointer(namep))
+	if e != 0 {
+		return nil, &DLLError{
+			Err:     e,
+			ObjName: name,
+			Msg:     "Failed to find " + name + " procedure in " + d.Name + ": " + e.Error(),
+		}
+	}
+	p := &Proc{
+		Dll:  d,
+		Name: name,
+		addr: a,
+	}
+	return p, nil
+}
+
+// MustFindProc is like FindProc but panics if search fails.
+func (d *DLL) MustFindProc(name string) *Proc {
+	p, e := d.FindProc(name)
+	if e != nil {
+		panic(e)
+	}
+	return p
+}
+
+// Release unloads DLL d from memory.
+func (d *DLL) Release() (err error) {
+	return FreeLibrary(d.Handle)
+}
+
+// A Proc implements access to a procedure inside a DLL.
+type Proc struct {
+	Dll  *DLL
+	Name string
+	addr uintptr
+}
+
+// Addr returns the address of the procedure represented by p.
+// The return value can be passed to Syscall to run the procedure.
+func (p *Proc) Addr() uintptr {
+	return p.addr
+}
+
+// Call executes procedure p with arguments a. It will panic, if more then 15 arguments
+// are supplied.
+//
+// The returned error is always non-nil, constructed from the result of GetLastError.
+// Callers must inspect the primary return value to decide whether an error occurred
+// (according to the semantics of the specific function being called) before consulting
+// the error. The error will be guaranteed to contain syscall.Errno.
+func (p *Proc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) {
+	switch len(a) {
+	case 0:
+		return Syscall(p.Addr(), uintptr(len(a)), 0, 0, 0)
+	case 1:
+		return Syscall(p.Addr(), uintptr(len(a)), a[0], 0, 0)
+	case 2:
+		return Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], 0)
+	case 3:
+		return Syscall(p.Addr(), uintptr(len(a)), a[0], a[1], a[2])
+	case 4:
+		return Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], 0, 0)
+	case 5:
+		return Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], 0)
+	case 6:
+		return Syscall6(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5])
+	case 7:
+		return Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], 0, 0)
+	case 8:
+		return Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], 0)
+	case 9:
+		return Syscall9(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8])
+	case 10:
+		return Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], 0, 0)
+	case 11:
+		return Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], 0)
+	case 12:
+		return Syscall12(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11])
+	case 13:
+		return Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], 0, 0)
+	case 14:
+		return Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], 0)
+	case 15:
+		return Syscall15(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14])
+	default:
+		panic("Call " + p.Name + " with too many arguments " + itoa(len(a)) + ".")
+	}
+	return
+}
+
+// A LazyDLL implements access to a single DLL.
+// It will delay the load of the DLL until the first
+// call to its Handle method or to one of its
+// LazyProc's Addr method.
+type LazyDLL struct {
+	mu   sync.Mutex
+	dll  *DLL // non nil once DLL is loaded
+	Name string
+}
+
+// Load loads DLL file d.Name into memory. It returns an error if fails.
+// Load will not try to load DLL, if it is already loaded into memory.
+func (d *LazyDLL) Load() error {
+	// Non-racy version of:
+	// if d.dll == nil {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&d.dll))) == nil {
+		d.mu.Lock()
+		defer d.mu.Unlock()
+		if d.dll == nil {
+			dll, e := LoadDLL(d.Name)
+			if e != nil {
+				return e
+			}
+			// Non-racy version of:
+			// d.dll = dll
+			atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&d.dll)), unsafe.Pointer(dll))
+		}
+	}
+	return nil
+}
+
+// mustLoad is like Load but panics if search fails.
+func (d *LazyDLL) mustLoad() {
+	e := d.Load()
+	if e != nil {
+		panic(e)
+	}
+}
+
+// Handle returns d's module handle.
+func (d *LazyDLL) Handle() uintptr {
+	d.mustLoad()
+	return uintptr(d.dll.Handle)
+}
+
+// NewProc returns a LazyProc for accessing the named procedure in the DLL d.
+func (d *LazyDLL) NewProc(name string) *LazyProc {
+	return &LazyProc{l: d, Name: name}
+}
+
+// NewLazyDLL creates new LazyDLL associated with DLL file.
+func NewLazyDLL(name string) *LazyDLL {
+	return &LazyDLL{Name: name}
+}
+
+// A LazyProc implements access to a procedure inside a LazyDLL.
+// It delays the lookup until the Addr method is called.
+type LazyProc struct {
+	mu   sync.Mutex
+	Name string
+	l    *LazyDLL
+	proc *Proc
+}
+
+// Find searches DLL for procedure named p.Name. It returns
+// an error if search fails. Find will not search procedure,
+// if it is already found and loaded into memory.
+func (p *LazyProc) Find() error {
+	// Non-racy version of:
+	// if p.proc == nil {
+	if atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&p.proc))) == nil {
+		p.mu.Lock()
+		defer p.mu.Unlock()
+		if p.proc == nil {
+			e := p.l.Load()
+			if e != nil {
+				return e
+			}
+			proc, e := p.l.dll.FindProc(p.Name)
+			if e != nil {
+				return e
+			}
+			// Non-racy version of:
+			// p.proc = proc
+			atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&p.proc)), unsafe.Pointer(proc))
+		}
+	}
+	return nil
+}
+
+// mustFind is like Find but panics if search fails.
+func (p *LazyProc) mustFind() {
+	e := p.Find()
+	if e != nil {
+		panic(e)
+	}
+}
+
+// Addr returns the address of the procedure represented by p.
+// The return value can be passed to Syscall to run the procedure.
+func (p *LazyProc) Addr() uintptr {
+	p.mustFind()
+	return p.proc.Addr()
+}
+
+// Call executes procedure p with arguments a. It will panic, if more then 15 arguments
+// are supplied.
+//
+// The returned error is always non-nil, constructed from the result of GetLastError.
+// Callers must inspect the primary return value to decide whether an error occurred
+// (according to the semantics of the specific function being called) before consulting
+// the error. The error will be guaranteed to contain syscall.Errno.
+func (p *LazyProc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) {
+	p.mustFind()
+	return p.proc.Call(a...)
+}