Merge pull request #757 from Elv13/properties

C-API objects properties

lib/awful/client.lua

@@ -10,6 +10,7 @@
 -- Grab environment we need
 local util = require("awful.util")
 local spawn = require("awful.spawn")
+local object = require("gears.object")
 local tag = require("awful.tag")
 local pairs = pairs
 local type = type
@@ -1104,6 +1105,7 @@ capi.client.add_signal("marked")
 capi.client.add_signal("unmarked")
 
 capi.client.connect_signal("focus", client.focus.history.add)
+
 -- Add clients during startup to focus history.
 -- This used to happen through ewmh.activate, but that only handles visible
 -- clients now.
@@ -1123,6 +1125,14 @@ capi.client.connect_signal("unmanage", client.floating.delete)
 -- Register persistent properties
 client.property.persist("floating", "boolean")
 
+-- Extend the luaobject
+object.properties(capi.client, {
+    getter_class    = client,
+    setter_class    = client,
+    getter_fallback = client.property.get,
+    setter_fallback = client.property.set,
+})
+
 return client
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

lib/awful/screen.lua

@@ -15,6 +15,7 @@ local capi =
     client = client
 }
 local util = require("awful.util")
+local object = require("gears.object")
 
 local function get_screen(s)
     return s and capi.screen[s]
@@ -245,6 +246,9 @@ end
 
 capi.screen.add_signal("padding")
 
+-- Extend the luaobject
+object.properties(capi.screen, {auto_emit=true})
+
 return screen
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

lib/awful/tag.lua

@@ -11,6 +11,7 @@
 local util = require("awful.util")
 local ascreen = require("awful.screen")
 local beautiful = require("beautiful")
+local object = require("gears.object")
 local pairs = pairs
 local ipairs = ipairs
 local table = table
@@ -873,6 +874,16 @@ function tag.mt:__call(...)
     return tag.new(...)
 end
 
+-- Extend the luaobject
+-- `awful.tag.setproperty` currently handle calling the setter method itself
+-- while `awful.tag.getproperty`.
+object.properties(capi.tag, {
+    getter_class    = tag,
+    setter_class    = tag,
+    getter_fallback = tag.getproperty,
+    setter          = tag.setproperty,
+})
+
 return setmetatable(tag, tag.mt)
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

lib/gears/object.lua

@@ -9,8 +9,9 @@ local setmetatable = setmetatable
 local pairs = pairs
 local type = type
 local error = error
+local properties = require("gears.object.properties")
 
-local object = { mt = {} }
+local object = { properties = properties, mt = {} }
 
 --- Verify that obj is indeed a valid object as returned by new()
 local function check(obj)

lib/gears/object/properties.lua

@@ -0,0 +1,103 @@
+---------------------------------------------------------------------------
+--- An helper module to map userdata __index and __newindex entries to
+-- lua classes.
+--
+-- @author Emmanuel Lepage-Vallee <elv1313@gmail.com>
+-- @copyright 2016 Emmanuel Lepage-Vallee
+-- @release @AWESOME_VERSION@
+-- @module gears.object.properties
+---------------------------------------------------------------------------
+
+local object = {}
+
+local properties = setmetatable({}, { __mode = 'k' })
+
+local function cobj_register(cobj)
+    local fallback = {}
+
+    function fallback:rawset(_, prop, val)
+        fallback[prop] = val
+    end
+
+    function fallback:rawget(_, prop)
+        return fallback[prop]
+    end
+
+    properties[cobj] = fallback
+    return fallback
+end
+
+--- Add the missing properties handler to a CAPI object such as client/tag/screen
+-- Valid args:
+--
+-- * **getter**: A smart getter (handle property getter itself)
+-- * **getter_fallback**: A dumb getter method (don't handle individual property getter)
+-- * **getter_class**: A module with individual property getter/setter
+-- * **getter_prefix**: A special getter prefix (like "get" or "get_" (default))
+-- * **setter**: A smart setter (handle property setter itself)
+-- * **setter_fallback**: A dumb setter method (don't handle individual property setter)
+-- * **setter_class**: A module with individual property getter/setter
+-- * **setter_prefix**: A special setter prefix (like "set" or "set_" (default))
+-- * **auto_emit**: Emit "property::___" automatically (default: false). This is
+--     ignored when setter_fallback is set or a setter is found
+--
+-- @param class A standard luaobject derived object
+-- @tparam[opt={}] table args A set of accessors configuration parameters
+function object.capi_index_fallback(class, args)
+    args = args or {}
+
+    local getter_prefix = args.getter_prefix or "get_"
+    local setter_prefix = args.setter_prefix or "set_"
+
+    local getter = args.getter or function(cobj, prop)
+        -- Look for a getter method
+        if args.getter_class and args.getter_class[getter_prefix..prop] then
+            return args.getter_class[getter_prefix..prop](cobj)
+        end
+
+        -- Make sure something like c:a_mutator() works
+        if args.getter_class and args.getter_class[prop] then
+            return args.getter_class[prop]
+        end
+
+        -- In case there is already a "dumb" getter like `awful.tag.getproperty'
+        if args.getter_fallback then
+            return args.getter_fallback(cobj, prop)
+        end
+
+        local fallback = properties[cobj] or cobj_register(cobj)
+
+        -- Use the fallback property table
+        return fallback[prop]
+    end
+
+    local setter = args.setter or function(cobj, prop, value)
+        -- Look for a setter method
+        if args.setter_class and args.setter_class[setter_prefix..prop] then
+            return args.setter_class[setter_prefix..prop](cobj, value)
+        end
+
+        -- In case there is already a "dumb" setter like `awful.client.property.set'
+        if args.setter_fallback then
+            return args.setter_fallback(cobj, prop, value)
+        end
+
+        local fallback = properties[cobj] or cobj_register(cobj)
+
+        -- Use the fallback property table
+        fallback[prop] = value
+
+        -- Emit the signal
+        if args.auto_emit then
+            cobj:emit_signal("property::"..prop, value)
+        end
+    end
+
+    -- Attach the accessor methods
+    class.set_index_miss_handler(getter)
+    class.set_newindex_miss_handler(setter)
+end
+
+return setmetatable( object, {__call = function(_,...) object.capi_index_fallback(...) end})
+
+-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

tests/test-miss-handlers.lua

@@ -2,6 +2,7 @@
 
 local class = tag
 local obj = class({})
+local handler = require("gears.object.properties")
 
 awesome.connect_signal("debug::index::miss", error)
 awesome.connect_signal("debug::newindex::miss", error)
@@ -23,4 +24,10 @@ end)
 obj.key = 42
 assert(called)
 
+handler(class, {auto_emit=true})
+
+assert(not obj.key)
+obj.key = 1337
+assert(obj.key == 1337)
+
 require("_runner").run_steps({ function() return true end })