[Search] Implementation of the invisible focus on Windows

chrome/browser/ui/views/omnibox/omnibox_view_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/omnibox/omnibox_view_win.h"
 
 #include <algorithm>
 #include <locale>
 #include <string>
 
@@ skipping 742 matching lines @@
   //   * The user has just pasted in something that replaced all the text
   //   * The user is trying to compose something in an IME
   CHARRANGE sel;
   GetSel(sel);
   model()->StartAutocomplete(sel.cpMax != sel.cpMin,
                             (sel.cpMax < GetTextLength()) || IsImeComposing());
 }
 
 void OmniboxViewWin::SetFocus() {
   ::SetFocus(m_hWnd);
+  // Restore caret visibility if focused explicitly. We need to do this here
+  // because if we already have invisible focus, the ::SetFocus call above will
+  // short-circuit, preventing us from reaching OmniboxEditModel::OnSetFocus(),
+  // which handles restoring visibility when we didn't previously have focus.
+  model()->SetCaretVisibility(true);
 }
 
 void OmniboxViewWin::ApplyCaretVisibility() {
-  // TODO(mathp): implement for Windows.
-  NOTIMPLEMENTED();
+  // We hide the caret just before destroying it, since destroying a caret that
+  // is in the "solid" phase of its blinking will leave a solid vertical bar.
+  // We even hide and destroy the caret if we're going to create it again below.
+  // If the caret was already visible on entry to this function, the
+  // CreateCaret() call (which first destroys the old caret) might leave a solid
+  // vertical bar for the same reason as above.  Unconditionally hiding prevents
+  // this.  The caret could be visible on entry to this function if the
+  // underlying edit control had re-created it automatically (see comments in
+  // OnPaint()).
+  HideCaret();
+  // We use DestroyCaret()/CreateCaret() instead of simply HideCaret()/
+  // ShowCaret() because HideCaret() is not sticky across paint events, e.g. a
+  // window resize will effectively restore caret visibility, regardless of
+  // whether HideCaret() was called before. While we do catch and handle these
+  // paint events (see OnPaint()), it doesn't seem to be enough to simply call
+  // HideCaret() while handling them because of the unpredictability of this
+  // Windows API. According to the documentation, it should be a cumulative call
+  // e.g. 5 hide calls should be balanced by 5 show calls. We have not found
+  // this to be true, which may be explained by the fact that this API is called
+  // internally in Windows, as well.
+  ::DestroyCaret();
+  if (model()->is_caret_visible()) {
+    ::CreateCaret(m_hWnd, (HBITMAP) NULL, 1, font_.GetHeight());
+    // According to the Windows API documentation, a newly created caret needs
+    // ShowCaret to be visible.
+    ShowCaret();
+  }
 }
 
 void OmniboxViewWin::SetDropHighlightPosition(int position) {
   if (drop_highlight_position_ != position) {
     RepaintDropHighlight(drop_highlight_position_);
     drop_highlight_position_ = position;
     RepaintDropHighlight(drop_highlight_position_);
   }
 }
 
@@ skipping 956 matching lines @@
   // First, give other handlers a chance to handle the message to see if we are
   // actually going to activate and gain focus.
   LRESULT result = DefWindowProc(WM_MOUSEACTIVATE,
                                  reinterpret_cast<WPARAM>(window),
                                  MAKELPARAM(hit_test, mouse_message));
   // Check if we're getting focus from a click.  We have to do this here rather
   // than in OnXButtonDown() since in many scenarios OnSetFocus() will be
   // reached before OnXButtonDown(), preventing us from detecting this properly
   // there.  Also in those cases, we need to already know in OnSetFocus() that
   // we should not restore the saved selection.
-  if (!model()->has_focus() &&
+  if ((!model()->has_focus() || !model()->is_caret_visible()) &&
       ((mouse_message == WM_LBUTTONDOWN || mouse_message == WM_RBUTTONDOWN)) &&
       (result == MA_ACTIVATE)) {
     if (gaining_focus_) {
       // On Windows 8 in metro mode, we get two WM_MOUSEACTIVATE messages when
       // we click on the omnibox with the mouse.
       DCHECK(base::win::IsMetroProcess());
       return result;
     }
     gaining_focus_.reset(new ScopedFreeze(this, GetTextObjectModel()));
+
+    // Explicitely set focus visibility in the case of clicking on the omnibox,
+    // which will remove invisible focus if present.
+    model()->SetCaretVisibility(true);
+
     // NOTE: Despite |mouse_message| being WM_XBUTTONDOWN here, we're not
     // guaranteed to call OnXButtonDown() later!  Specifically, if this is the
     // second click of a double click, we'll reach here but later call
     // OnXButtonDblClk().  Make sure |gaining_focus_| gets reset both places,
     // or we'll have visual glitchiness and then DCHECK failures.
 
     // Don't restore saved selection, it will just screw up our interaction
     // with this edit.
     saved_selection_for_focus_change_.cpMin = -1;
   }
@@ skipping 128 matching lines @@
 
   // Draw the drop highlight.
   if (drop_highlight_position_ != -1)
     DrawDropHighlight(memory_dc, rect, paint_clip_rect);
 
   // Blit the memory DC to the actual paint DC and clean up.
   BitBlt(paint_dc, rect.left, rect.top, rect.Width(), rect.Height(), memory_dc,
          rect.left, rect.top, SRCCOPY);
   memory_dc.SelectBitmap(old_bitmap);
   edit_hwnd = old_edit_hwnd;
+
+  // This needs to be called regardless of the current state of the caret, even
+  // if reaffirming a current state (hidden or shown). This is because the
+  // underlying edit control will automatically re-create the caret when it
+  // receives certain events that trigger repaints, e.g. window resize events.
+  ApplyCaretVisibility();
 }
 
 void OmniboxViewWin::OnPaste() {
   // Replace the selection if we have something to paste.
   const string16 text(GetClipboardText());
   if (!text.empty()) {
     // Record this paste, so we can do different behavior.
     model()->on_paste();
     // Force a Paste operation to trigger the text_changed code in
     // OnAfterPossibleChange(), even if identical contents are pasted into the
@@ skipping 839 matching lines @@
   return (rect.left - client_rect.left) + (client_rect.right - rect.right);
 }
 
 int OmniboxViewWin::WidthNeededToDisplay(const string16& text) const {
   // Use font_.GetStringWidth() instead of
   // PosFromChar(location_entry_->GetTextLength()) because PosFromChar() is
   // apparently buggy. In both LTR UI and RTL UI with left-to-right layout,
   // PosFromChar(i) might return 0 when i is greater than 1.
   return font_.GetStringWidth(text) + GetHorizontalMargin();
 }