layout.flex: Base on layout.fixed rather than widget.base

This remove duplicated code and will allow more "collection"
style layouts to be implemented without logic duplication.

This commit also do some small cleanup to remove duplicated
code now present in `awful.util`.

Fixes https://github.com/awesomeWM/awesome/issues/617

lib/wibox/layout/fixed.lua

@@ -8,6 +8,7 @@
 local base  = require("wibox.widget.base")
 local table = table
 local pairs = pairs
+local util = require("awful.util")
 
 local fixed = {}
 
@@ -122,11 +123,7 @@ end
 local function get_layout(dir, widget1, ...)
     local ret = base.make_widget()
 
-    for k, v in pairs(fixed) do
-        if type(v) == "function" then
-            ret[k] = v
-        end
-    end
+    util.table.crush(ret, fixed)
 
     ret.dir = dir
     ret.widgets = {}

lib/wibox/layout/flex.lua

@@ -6,16 +6,49 @@
 ---------------------------------------------------------------------------
 
 local base = require("wibox.widget.base")
+local fixed = require("wibox.layout.fixed")
 local table = table
 local pairs = pairs
 local floor = math.floor
-local round = require("awful.util").round
+local util = require("awful.util")
 
 local flex = {}
 
-local function round(x)
-    return floor(x + 0.5)
-end
+--- Layout a fixed layout. Each widget gets just the space it asks for.
+-- @param layout The layout you are modifying.
+-- @param context The context in which we are drawn.
+-- @param width The available width.
+-- @param height The available height.
+-- @name layout
+-- @class function
+
+--- Get all children of this layout
+-- @param layout The layout you are modifying.
+-- @warning If the widget contain itself and recursive is true, this will cause
+--   a stack overflow
+-- @param[opt] recursive Also add all widgets of childrens
+-- @return a list of all widgets
+-- @name get_children
+-- @class function
+
+--- Add some widgets to the given fixed layout
+-- @param layout The layout you are modifying.
+-- @tparam widget ... Widgets that should be added (must at least be one)
+-- @name add
+-- @class function
+
+--- Fit the fixed layout into the given space
+-- @param layout The layout you are modifying.
+-- @param context The context in which we are fit.
+-- @param orig_width The available width.
+-- @param orig_height The available height.
+-- @name fit
+-- @class function
+
+--- Reset a fixed layout. This removes all widgets from the layout.
+-- @param layout The layout you are modifying.
+-- @name reset
+-- @class function
 
 --- Layout a flex layout. Each widget gets an equal share of the available space.
 -- @param context The context in which we are drawn.
@@ -41,12 +74,13 @@ function flex:layout(context, width, height)
     for k, v in pairs(self.widgets) do
         local x, y, w, h
         if self.dir == "y" then
-            x, y = 0, round(pos)
+            x, y = 0, util.round(pos)
             w, h = width, floor(space_per_item)
         else
-            x, y = round(pos), 0
+            x, y = util.round(pos), 0
             w, h = floor(space_per_item), height
         end
+
         table.insert(result, base.place_widget_at(v, x, y, w, h))
 
         pos = pos + space_per_item + spacing
@@ -96,19 +130,6 @@ function flex:fit(context, orig_width, orig_height)
     return used_in_dir + spacing, used_in_other
 end
 
---- Add some widgets to the given flex layout
--- @tparam widget ... Widgets that should be added (must at least be one)
-function flex:add(...)
-    -- No table.pack in Lua 5.1 :-(
-    local args = { n=select('#', ...), ... }
-    assert(args.n > 0, "need at least one widget to add")
-    for i=1, args.n do
-        base.check_widget(args[i])
-        table.insert(self.widgets, args[i])
-    end
-    self:emit_signal("widget::layout_changed")
-end
-
 --- Set the maximum size the widgets in this layout will take (that is,
 -- maximum width for horizontal and maximum height for vertical).
 -- @param val The maximum size of the widget.
@@ -119,37 +140,12 @@ function flex:set_max_widget_size(val)
     end
 end
 
---- Add spacing between each layout widgets
--- @param spacing Spacing between widgets.
-function flex:set_spacing(spacing)
-    if self._spacing ~= spacing then
-        self._spacing = spacing
-        self:emit_signal("widget::layout_changed")
-    end
-end
-
-function flex:reset()
-    self.widgets = {}
-    self._max_widget_size = nil
-    self:emit_signal("widget::layout_changed")
-end
-
 local function get_layout(dir, widget1, ...)
-    local ret = base.make_widget()
+    local ret = fixed[dir](widget1, ...)
 
-    for k, v in pairs(flex) do
-        if type(v) == "function" then
-            ret[k] = v
-        end
-    end
+    util.table.crush(ret, flex)
 
-    ret.dir = dir
-    ret.widgets = {}
-    ret:set_spacing(0)
-
-    if widget1 then
-        ret:add(widget1, ...)
-    end
+    ret.fill_space = nil
 
     return ret
 end
@@ -158,14 +154,14 @@ end
 -- equally among all widgets. Widgets can be added via :add(widget).
 -- @tparam widget ... Widgets that should be added to the layout.
 function flex.horizontal(...)
-    return get_layout("x", ...)
+    return get_layout("horizontal", ...)
 end
 
 --- Returns a new vertical flex layout. A flex layout shares the available space
 -- equally among all widgets. Widgets can be added via :add(widget).
 -- @tparam widget ... Widgets that should be added to the layout.
 function flex.vertical(...)
-    return get_layout("y", ...)
+    return get_layout("vertical", ...)
 end
 
 return flex