Initial implementation of shortcut to windows

[PURPOSE]

In editors such as vi and emacs, a user can mark a line in a file with
a shortcut key and afterwards jump back to that line using the shortcut.

The idea is extended to opened windows. A user can assign a keyboard
shortcut to an opened window.  Afterwards, the shortcut can be used to
switch focus back to the marked window.

Such shortcuts save the user from pressing "alt+tab" multiple times to
cycle through windows until the desired one is found.

[EXAMPLE USAGE]

The following binding is added to file "~/.fluxbox/keys":

    Mod1 m ARG :MarkWindow

    Mod1 g ARG :GotoMarkedWindow

User enters "alt+m x" to mark the currently focused window with shortcut
key 'x'

User enters "alt+g x" to switch focus to the marked window

[IMPLEMENTATION SUMMARY]

- Two new commands were added :MarkWindow and :GotoMarkedWindow

- Keys.cc was modified:
    - addBinding() method supports parsing an argument placeholder where
      the user can pass in a shortcut key
    - doAction() method forwards the shortcut key to the command to execute
    - Class Keys::t_key was modified to recognize a placeholder key

- New class ShortcutManager was added to maintain mapping of shortcut
  keys to marked windows

1 files changed, 45 insertions, 0 deletions

diff --git a/src/ShortcutManager.cc b/src/ShortcutManager.cc
new file mode 100644
index 0000000..52e94af
--- /dev/null
+++ b/src/ShortcutManager.cc
@@ -0,0 +1,45 @@
+#include "ShortcutManager.hh"
+#include "Debug.hh"
+
+#include <iostream>
+
+ShortcutManager::ShortcutManager() : m_last_placeholder_key(0) { }
+
+void ShortcutManager::setLastPlaceHolderKey(unsigned int lastPlaceHolderKey_)
+{
+    m_last_placeholder_key = lastPlaceHolderKey_;
+}
+
+unsigned int ShortcutManager::getLastPlaceHolderKey()
+{
+    return m_last_placeholder_key;
+}
+
+void ShortcutManager::mapKeyToWindow(unsigned int key, FluxboxWindow* window)
+{
+    m_key_to_window_map.insert(std::make_pair(key, window));
+}
+
+void ShortcutManager::removeWindow(FluxboxWindow* window)
+{
+    KeyToWindowMap::const_iterator it;
+    for (it = m_key_to_window_map.begin(); it != m_key_to_window_map.end(); ++it) {
+        if (it->second == window){
+            fbdbg << "Remove mapping window[" << window
+                  << "] key [" << it->first << "]" << std::endl;
+            m_key_to_window_map.erase(it);
+            return;
+        }
+    }
+}
+
+FluxboxWindow* ShortcutManager::getWindowForKey(unsigned int key)
+{
+    KeyToWindowMap::const_iterator it = m_key_to_window_map.find(key);
+    if (it != m_key_to_window_map.end()) {
+        return it->second;
+    }
+    else {
+        return nullptr;
+    }
+}