From e06e32715552764769e85c72a43bf5ee78e5f555 Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Wed, 20 Aug 2014 12:04:36 -0400
Subject: [PATCH] Implemented TextField.OnChanged() on Windows.

---
 redo/basicctrls_windows.c | 26 ++++++++++++++++++++++++++
 redo/textfield_windows.go | 24 +++++++++++++++++++++++-
 redo/winapi_windows.h     |  1 +
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/redo/basicctrls_windows.c b/redo/basicctrls_windows.c
index a703d75..1676776 100644
--- a/redo/basicctrls_windows.c
+++ b/redo/basicctrls_windows.c
@@ -78,3 +78,29 @@ void checkboxSetChecked(HWND hwnd, BOOL c)
 		check = BST_UNCHECKED;
 	SendMessage(hwnd, BM_SETCHECK, check, 0);
 }
+
+static LRESULT CALLBACK textfieldSubProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR id, DWORD_PTR data)
+{
+	switch (uMsg) {
+	case msgCOMMAND:
+		if (HIWORD(wParam) == EN_CHANGE) {
+			textfieldChanged((void *) data);
+			return 0;
+		}
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	case WM_NCDESTROY:
+		if ((*fv_RemoveWindowSubclass)(hwnd, textfieldSubProc, id) == FALSE)
+			xpanic("error removing TextField subclass (which was for its own event handler)", GetLastError());
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	default:
+		return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
+	}
+	xmissedmsg("TextField", "textfieldSubProc()", uMsg);
+	return 0;		// unreached
+}
+
+void setTextFieldSubclass(HWND hwnd, void *data)
+{
+	if ((*fv_SetWindowSubclass)(hwnd, textfieldSubProc, 0, (DWORD_PTR) data) == FALSE)
+		xpanic("error subclassing TextField to give it its own event handler", GetLastError());
+}
diff --git a/redo/textfield_windows.go b/redo/textfield_windows.go
index 701c2b6..7345205 100644
--- a/redo/textfield_windows.go
+++ b/redo/textfield_windows.go
@@ -2,12 +2,17 @@
 
 package ui
 
+import (
+	"unsafe"
+)
+
 // #include "winapi_windows.h"
 import "C"
 
 type textfield struct {
 	_hwnd	C.HWND
 	_textlen	C.LONG
+	changed	*event
 }
 
 var editclass = toUTF16("EDIT")
@@ -17,9 +22,11 @@ func startNewTextField(style C.DWORD) *textfield {
 		style | C.ES_AUTOHSCROLL | C.ES_LEFT | C.ES_NOHIDESEL | C.WS_TABSTOP,
 		C.WS_EX_CLIENTEDGE)		// WS_EX_CLIENTEDGE without WS_BORDER will show the canonical visual styles border (thanks to MindChild in irc.efnet.net/#winprog)
 	t := &textfield{
-		_hwnd:	hwnd,
+		_hwnd:		hwnd,
+		changed:		newEvent(),
 	}
 	C.controlSetControlFont(t._hwnd)
+	C.setTextFieldSubclass(t._hwnd, unsafe.Pointer(t))
 	return t
 }
 
@@ -39,6 +46,21 @@ func (t *textfield) SetText(text string) {
 	baseSetText(t, text)
 }
 
+func (t *textfield) OnChanged(f func()) {
+	t.changed.set(f)
+}
+
+func (t *textfield) Invalid(reason string) {
+	// TODO
+}
+
+//export textfieldChanged
+func textfieldChanged(data unsafe.Pointer) {
+	t := (*textfield)(data)
+println("changed")
+	t.changed.fire()
+}
+
 func (t *textfield) hwnd() C.HWND {
 	return t._hwnd
 }
diff --git a/redo/winapi_windows.h b/redo/winapi_windows.h
index 199f838..ea9fe17 100644
--- a/redo/winapi_windows.h
+++ b/redo/winapi_windows.h
@@ -63,6 +63,7 @@ extern void setButtonSubclass(HWND, void *);
 extern void setCheckboxSubclass(HWND, void *);
 extern BOOL checkboxChecked(HWND);
 extern void checkboxSetChecked(HWND, BOOL);
+extern void setTextFieldSubclass(HWND, void *);
 
 // init_windows.c
 extern HINSTANCE hInstance;