Keymap: Add Defaults button to revert keymap

Fixes #9980

Since hrev44455 we save your modifier keys settings when you switch
keymaps so you could get your modifiers keys messed up and unable to
get back to normal. This Defaults button allows you to override all
that and go back to the default US-International keymap with default
modifiers so you can start with a fresh slate and set things up the
way you want.

Also moved Revert button to the left side next to the Defaults button.
We do this on other preflets, the right side is reserved for an Apply
or OK button, and, if the preflet doesn't have one, is left empty.

src/preferences/keymap/Keymap.cpp

@@ -17,6 +17,8 @@
 
 #include <ByteOrder.h>
 #include <File.h>
+#include <FindDirectory.h>
+#include <Path.h>
 
 #include <input_globals.h>
 
@@ -336,6 +338,23 @@ Keymap::SetDeadKeyTrigger(dead_key_index deadKeyIndex, const BString& trigger)
 }
 
 
+status_t
+Keymap::RestoreSystemDefault()
+{
+	BPath path;
+	status_t status = find_directory(B_USER_SETTINGS_DIRECTORY, &path);
+	if (status != B_OK)
+		return status;
+
+	path.Append("Key_map");
+
+	BEntry entry(path.Path());
+	entry.Remove();
+
+	return Use();
+}
+
+
 //! We make our input server use the map in /boot/home/config/settings/Keymap
 status_t
 Keymap::Use()

src/preferences/keymap/Keymap.h

@@ -48,6 +48,7 @@ public:
 			void				SetDeadKeyTrigger(dead_key_index deadKeyIndex,
 									const BString& trigger);
 
+			status_t			RestoreSystemDefault();
 			status_t			Use();
 
 			void				SetKey(uint32 keyCode, uint32 modifiers,

src/preferences/keymap/KeymapWindow.cpp

@@ -55,6 +55,7 @@ static const uint32 kMsgMenuFontChanged = 'mMFC';
 static const uint32 kMsgSystemMapSelected = 'SmST';
 static const uint32 kMsgUserMapSelected = 'UmST';
 
+static const uint32 kMsgDefaultKeymap = 'Dflt';
 static const uint32 kMsgRevertKeymap = 'Rvrt';
 static const uint32 kMsgKeymapUpdated = 'kMup';
 
@@ -67,6 +68,7 @@ static const uint32 kMsgDeadKeyTildeChanged = 'dkTc';
 static const char* kDeadKeyTriggerNone = "<none>";
 
 static const char* kCurrentKeymapName = "(Current)";
+static const char* kDefaultKeymapName = "US-International";
 
 
 KeymapWindow::KeymapWindow()
@@ -85,9 +87,6 @@ KeymapWindow::KeymapWindow()
 	fSwitchShortcutsButton = new BButton("switch", "",
 		new BMessage(kMsgSwitchShortcuts));
 
-	fRevertButton = new BButton("revertButton", B_TRANSLATE("Revert"),
-		new BMessage(kMsgRevertKeymap));
-
 	// controls pane
 	AddChild(BGroupLayoutBuilder(B_VERTICAL)
 		.Add(_CreateMenu())
@@ -103,8 +102,12 @@ KeymapWindow::KeymapWindow()
 				.Add(fTextControl)
 				.AddGlue(0.0)
 				.Add(BGroupLayoutBuilder(B_HORIZONTAL, 10)
-					.AddGlue(0.0)
-					.Add(fRevertButton)))
+					.Add(fDefaultsButton = new BButton("defaultsButton",
+						B_TRANSLATE("Defaults"),
+							new BMessage(kMsgDefaultKeymap)))
+					.Add(fRevertButton = new BButton("revertButton",
+						B_TRANSLATE("Revert"), new BMessage(kMsgRevertKeymap)))
+					.AddGlue()))
 			.SetInsets(10, 10, 10, 10)));
 
 	fKeyboardLayoutView->SetTarget(fTextControl->TextView());
@@ -292,6 +295,11 @@ KeymapWindow::MessageReceived(BMessage* message)
 			break;
 		}
 
+		case kMsgDefaultKeymap:
+			_DefaultKeymap();
+			_UpdateButtons();
+			break;
+
 		case kMsgRevertKeymap:
 			_RevertKeymap();
 			_UpdateButtons();
@@ -735,6 +743,8 @@ KeymapWindow::_UpdateButtons()
 		_UseKeymap();
 	}
 
+	fDefaultsButton->SetEnabled(
+		fCurrentMapName.ICompare(kDefaultKeymapName) != 0);
 	fRevertButton->SetEnabled(fCurrentMap != fPreviousMap);
 
 	_UpdateDeadKeyMenu();
@@ -763,6 +773,20 @@ KeymapWindow::_SwitchShortcutKeys()
 }
 
 
+//!	Restores the default keymap.
+void
+KeymapWindow::_DefaultKeymap()
+{
+	fCurrentMap.RestoreSystemDefault();
+	fAppliedMap = fCurrentMap;
+
+	fKeyboardLayoutView->SetKeymap(&fCurrentMap);
+
+	fCurrentMapName = _GetActiveKeymapName();
+	_SelectCurrentMap();
+}
+
+
 //!	Saves previous map to the "Key_map" file.
 void
 KeymapWindow::_RevertKeymap()

src/preferences/keymap/KeymapWindow.h

@@ -51,6 +51,7 @@ protected:
 			void				_SwitchShortcutKeys();
 
 			void				_UseKeymap();
+			void				_DefaultKeymap();
 			void				_RevertKeymap();
 
 			BMenuField*			_CreateDeadKeyMenuField();
@@ -74,6 +75,7 @@ protected:
 private:
 			BListView*			fSystemListView;
 			BListView*			fUserListView;
+			BButton*			fDefaultsButton;
 			BButton*			fRevertButton;
 			BMenu*				fLayoutMenu;
 			BMenu*				fFontMenu;