Abstract binding configuration to bindings.[ch]

Create files bindings.[ch] to contain functions for configuring,
finding, and running bindings.

Use the new function `configure_binding` for binding configuration. This
function adds a binding from config parameters.

Export the function `modifiers_from_str` from config_directives.h.

This change is made in preparation for the new bindmouse functionality.

include/all.h

@@ -79,6 +79,7 @@
 #include "scratchpad.h"
 #include "commands.h"
 #include "commands_parser.h"
+#include "bindings.h"
 #include "config_directives.h"
 #include "config_parser.h"
 #include "fake_outputs.h"

include/bindings.h

@@ -0,0 +1,25 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ * © 2009-2014 Michael Stapelberg and contributors (see also: LICENSE)
+ *
+ * bindings.h: Functions for configuring, finding, and running bindings.
+ *
+ */
+#pragma once
+
+/**
+ * The name of the default mode.
+ *
+ */
+const char *DEFAULT_BINDING_MODE;
+
+/**
+ * Adds a binding from config parameters given as strings and returns a
+ * pointer to the binding structure. Returns NULL if the input code could not
+ * be parsed.
+ *
+ */
+Binding *configure_binding(const char *bindtype, const char *modifiers, const char *input_code,
+        const char *release, const char *command, const char *mode);

include/config_directives.h

@@ -11,6 +11,12 @@
 
 #include "config_parser.h"
 
+/**
+ * A utility function to convert a string of modifiers to the corresponding bit
+ * mask.
+ */
+uint32_t modifiers_from_str(const char *str);
+
 /** The beginning of the prototype for every cfg_ function. */
 #define I3_CFG Match *current_match, struct ConfigResult *result