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/* wptSafeEditCtrl.cpp - Safe edit control for passwords |
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* Copyright (C) 2006 Timo Schulz, g10 Code GmbH |
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* |
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* This file is part of WinPT. |
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* |
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* WinPT is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* WinPT is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with WinPT; if not, write to the Free Software Foundation, |
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA |
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*/ |
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#ifdef HAVE_CONFIG_H |
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#include <config.h> |
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#endif |
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|
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#include <windows.h> |
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#include <stdio.h> |
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#include <richedit.h> |
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#include "resource.h" |
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|
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#include "wptTypes.h" |
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#include "wptW32API.h" |
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|
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/* New message to retrieve text. */ |
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#define WM_SAFE_GETTEXT (WM_USER+11) |
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|
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/* Hook context. */ |
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struct hook_ctx_s { |
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HHOOK keyb; /* handle for the keyboard. */ |
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HHOOK cbt; /* handle for computer based training (CBT) */ |
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}; |
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typedef struct hook_ctx_s *hook_ctx_t; |
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|
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/* Subclassing context. */ |
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struct subclass_ctx_s { |
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WNDPROC new_wnd_fnc; /* old window procedure. */ |
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WNDPROC old_wnd_fnc; /* new window procedure. */ |
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HWND wnd; /* window handle that is subclassed. */ |
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void *opaque; |
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}; |
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typedef struct subclass_ctx_s *subclass_ctx_t; |
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|
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|
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/* Dummy hook procedure to avoid channing. */ |
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static LRESULT CALLBACK |
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dummy_hook_proc (int code, WPARAM wparam, LPARAM lparam) |
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{ |
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return FALSE; |
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} |
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|
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|
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/* Set dummy hooks to prevent that the control is monitored |
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by some external hook functions. */ |
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static hook_ctx_t |
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install_dummy_hooks (void) |
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{ |
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hook_ctx_t hc; |
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|
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hc = (hook_ctx_t)calloc (1, sizeof *hc); |
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if (!hc) |
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return NULL; |
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hc->cbt = SetWindowsHookEx (WH_CBT, dummy_hook_proc, |
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GetModuleHandle (NULL), 0); |
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if (hc->cbt == NULL) { |
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free (hc); |
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return NULL; |
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} |
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hc->keyb = SetWindowsHookEx (WH_KEYBOARD, dummy_hook_proc, |
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GetModuleHandle (NULL), 0); |
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if (hc->keyb == NULL) { |
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free (hc); |
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return NULL; |
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} |
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return hc; |
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} |
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|
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|
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/* Remove dummy hooks and free memory. */ |
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static void |
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deinstall_dummy_hooks (hook_ctx_t hc) |
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{ |
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UnhookWindowsHookEx (hc->cbt); |
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UnhookWindowsHookEx (hc->keyb); |
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free (hc); |
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} |
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|
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|
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/* Filtered window procedure for the passphrase edit control. */ |
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static LRESULT CALLBACK |
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safe_edit_dlg_proc (HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam) |
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{ |
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static subclass_ctx_t ctx = NULL; |
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|
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/* XXX: filter all messages which were not send from |
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the current process. */ |
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|
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if (ctx == NULL) |
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ctx = (subclass_ctx_t)GetWindowLong (hwnd, GWL_USERDATA); |
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|
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switch (msg) { |
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case WM_CUT: |
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case WM_COPY: |
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case WM_PASTE: |
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/* do not allow to copy or paste the inserted text. */ |
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return TRUE; |
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|
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case WM_KEYUP: |
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case WM_KEYDOWN: |
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/* XXX: maybe in a future release, we might want to provide |
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our own buffer implementation. */ |
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|
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/* ignore 'end' and 'home' to make text selection more difficult. */ |
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if ((int)wparam == VK_END || (int)wparam == VK_HOME) |
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return TRUE; |
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break; |
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|
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case WM_GETTEXT: |
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/* disallow normal gettext message. */ |
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return TRUE; |
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|
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case WM_SAFE_GETTEXT: |
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{ /* transform WM_GETTEXT request into EM_GETLINE request. */ |
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char *buffer = (char*)wparam; |
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int n; |
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buffer[0] = (char)lparam; |
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n = SendMessage (hwnd, EM_GETLINE, 0, wparam); |
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buffer[n] = 0; |
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} |
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break; |
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|
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case EM_GETLINE: |
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break; |
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|
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case WM_LBUTTONDBLCLK: |
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case WM_RBUTTONUP: |
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case WM_RBUTTONDOWN: |
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/* prevent that the popup menu is displayed. */ |
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return TRUE; |
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|
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case EM_SETSEL: |
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case EM_SCROLLCARET: |
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case EM_FINDTEXT: |
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case EM_FINDTEXTEX: |
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case EM_GETSELTEXT: |
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case EM_PASTESPECIAL: |
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case EM_GETTEXTRANGE: |
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case EM_STREAMIN: |
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case EM_STREAMOUT: |
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/* disallow message which could be used to copy the text. */ |
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return TRUE; |
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} |
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|
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return CallWindowProc (ctx->old_wnd_fnc, hwnd, msg, wparam, lparam); |
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} |
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|
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|
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/* Sublclass the window in the dialog @dlg with the id @ctrlid. |
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@new_wnd_fnc is the new window procedure. */ |
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static int |
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subclass_window (HWND dlg, int ctrlid, WNDPROC new_wnd_fnc, |
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subclass_ctx_t *r_ctx) |
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{ |
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subclass_ctx_t ctx; |
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|
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*r_ctx = NULL; |
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ctx = (subclass_ctx_t)calloc (1, sizeof *ctx); |
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if (!ctx) |
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return -1; |
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ctx->wnd = GetDlgItem (dlg, ctrlid); |
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ctx->new_wnd_fnc = new_wnd_fnc; |
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ctx->old_wnd_fnc = (WNDPROC)GetWindowLong (ctx->wnd, GWL_WNDPROC); |
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if (!ctx->old_wnd_fnc) { |
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free (ctx); |
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return -1; |
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} |
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SetLastError (0); |
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SetWindowLong (ctx->wnd, GWL_WNDPROC, (LONG)new_wnd_fnc); |
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if (GetLastError () != 0) { |
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free (ctx); |
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return -1; |
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} |
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SetLastError (0); |
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SetWindowLong (ctx->wnd, GWL_USERDATA, (LONG)ctx); |
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if (GetLastError () != 0) { |
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free (ctx); |
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return -1; |
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} |
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if (r_ctx) |
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*r_ctx = ctx; |
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return 0; |
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} |
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|
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|
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/* Restore the old window procedure for the subclassed control |
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and free the memory. */ |
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static void |
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subclass_free_memory (HWND dlg, int ctrlid) |
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{ |
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subclass_ctx_t ctx; |
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HWND wnd; |
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|
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wnd = GetDlgItem (dlg, ctrlid); |
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ctx = (subclass_ctx_t)GetWindowLong (wnd, GWL_USERDATA); |
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SetWindowLong (ctx->wnd, GWL_WNDPROC, (LONG)ctx->old_wnd_fnc); |
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if (ctx != NULL) |
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free (ctx); |
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} |
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|
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|
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/* Init subclassing to provide a safer edit control |
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for the dialog @dlg control @ctlid. */ |
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void |
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safe_edit_control_init (HWND dlg, int ctlid) |
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{ |
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subclass_ctx_t ctx; |
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|
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subclass_window (dlg, ctlid, safe_edit_dlg_proc, &ctx); |
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if (ctx != NULL) |
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ctx->opaque = install_dummy_hooks (); |
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} |
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|
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|
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/* Reset subclassing for the edit control @ctlid. */ |
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void |
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safe_edit_control_free (HWND dlg, int ctlid) |
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{ |
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subclass_ctx_t ctx; |
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HWND wnd; |
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|
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wnd = GetDlgItem (dlg, ctlid); |
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ctx = (subclass_ctx_t)GetWindowLong (wnd, GWL_USERDATA); |
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if (ctx != NULL && ctx->opaque != NULL) |
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deinstall_dummy_hooks ((hook_ctx_t)ctx->opaque); |
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subclass_free_memory (dlg, ctlid); |
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} |
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|
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|
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UINT |
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SafeGetDlgItemText (HWND dlg, int id, char *buf, int buflen) |
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{ |
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memset (buf, 0, buflen); |
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SendDlgItemMessage (dlg, id, WM_SAFE_GETTEXT, (WPARAM)buf, (LPARAM)buflen); |
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return strlen (buf); |
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} |
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|
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