Merge pull request #913 from Elv13/gear_obj_props

Gear.object properties

lib/gears/object.lua

@@ -1,4 +1,9 @@
 ---------------------------------------------------------------------------
+-- The object oriented programming base class used by various Awesome
+-- widgets and components.
+--
+-- It provide basic observer pattern, signaling and dynamic properties.
+--
 -- @author Uli Schlachter
 -- @copyright 2010 Uli Schlachter
 -- @release @AWESOME_VERSION@
@@ -21,10 +26,10 @@ local function check(obj)
 end
 
 --- Find a given signal
--- @param obj The object to search in
--- @param name The signal to find
--- @param error_msg Error message for if the signal is not found
--- @return The signal table
+-- @tparam table obj The object to search in
+-- @tparam string name The signal to find
+-- @tparam string error_msg Error message for if the signal is not found
+-- @treturn table The signal table
 local function find_signal(obj, name, error_msg)
     check(obj)
     if not obj._signals[name] then
@@ -34,7 +39,9 @@ local function find_signal(obj, name, error_msg)
 end
 
 --- Add a signal to an object. All signals must be added before they can be used.
--- @param name The name of the new signal.
+--
+--@DOC_text_gears_object_signal_EXAMPLE@
+-- @tparam string name The name of the new signal.
 function object:add_signal(name)
     check(self)
     assert(type(name) == "string", "name must be a string, got: " .. type(name))
@@ -46,9 +53,10 @@ function object:add_signal(name)
     end
 end
 
---- Connect to a signal
--- @param name The name of the signal
--- @param func The callback to call when the signal is emitted
+--- Connect to a signal.
+-- @tparam string name The name of the signal
+-- @tparam function func The callback to call when the signal is emitted
+-- @see add_signal 
 function object:connect_signal(name, func)
     assert(type(func) == "function", "callback must be a function, got: " .. type(func))
     local sig = find_signal(self, name, "connect to")
@@ -88,8 +96,8 @@ end
 
 --- Connect to a signal weakly. This allows the callback function to be garbage
 -- collected and automatically disconnects the signal when that happens.
--- @param name The name of the signal
--- @param func The callback to call when the signal is emitted
+-- @tparam string name The name of the signal
+-- @tparam function func The callback to call when the signal is emitted
 function object:weak_connect_signal(name, func)
     assert(type(func) == "function", "callback must be a function, got: " .. type(func))
     local sig = find_signal(self, name, "connect to")
@@ -97,18 +105,19 @@ function object:weak_connect_signal(name, func)
     sig.weak[func] = make_the_gc_obey(func)
 end
 
---- Disonnect to a signal
--- @param name The name of the signal
--- @param func The callback that should be disconnected
+--- Disonnect to a signal.
+-- @tparam string name The name of the signal
+-- @tparam function func The callback that should be disconnected
+-- @see add_signal
 function object:disconnect_signal(name, func)
     local sig = find_signal(self, name, "disconnect from")
     sig.weak[func] = nil
     sig.strong[func] = nil
 end
 
---- Emit a signal
+--- Emit a signal.
 --
--- @param name The name of the signal
+-- @tparam string name The name of the signal
 -- @param ... Extra arguments for the callback functions. Each connected
 --   function receives the object as first argument and then any extra arguments
 --   that are given to emit_signal()
@@ -122,11 +131,59 @@ function object:emit_signal(name, ...)
     end
 end
 
---- Returns a new object. You can call :emit_signal(), :disconnect_signal,
--- :connect_signal() and :add_signal() on the resulting object.
-local function new()
+local function get_miss(self, key)
+    local class = rawget(self, "_class")
+
+    if rawget(self, "get_"..key) then
+        return rawget(self, "get_"..key)(self)
+    elseif class and class["get_"..key] then
+        return class["get_"..key](self)
+    elseif class then
+        return class[key]
+    end
+
+end
+
+local function set_miss(self, key, value)
+    local class = rawget(self, "_class")
+
+    if rawget(self, "set_"..key) then
+        return rawget(self, "set_"..key)(self, value)
+    elseif class and class["set_"..key] then
+        return class["set_"..key](self, value)
+    elseif rawget(self, "_enable_auto_signals") then
+        local changed = class[key] ~= value
+        class[key] = value
+
+        if changed then
+            self:emit_signal("property::"..key, value)
+        end
+    else
+        return rawset(self, key, value)
+    end
+end
+
+--- Returns a new object. You can call `:emit_signal()`, `:disconnect_signal()`,
+-- `:connect_signal()` and `:add_signal()` on the resulting object.
+--
+-- Note that `args.enable_auto_signals` is only supported when
+-- `args.enable_properties` is true.
+--
+--@DOC_text_gears_object_properties_EXAMPLE@
+-- @tparam[opt={}] table args The arguments
+-- @tparam[opt=false] boolean args.enable_properties Automatically call getters and setters
+-- @tparam[opt=false] boolean args.enable_auto_signals Generate "property::xxxx" signals
+--   when an unknown property is set.
+-- @tparam[opt=nil] table args.class
+-- @treturn table A new object
+-- @function gears.object
+local function new(args)
+    args = args or {}
     local ret = {}
 
+    -- Automatic signals cannot work without both miss handlers.
+    assert(not (args.enable_auto_signals and args.enable_properties ~= true))
+
     -- Copy all our global functions to our new object
     for k, v in pairs(object) do
         if type(v) == "function" then
@@ -136,7 +193,27 @@ local function new()
 
     ret._signals = {}
 
-    return ret
+    local mt = {}
+
+    -- Look for methods in another table
+    ret._class               = args.class
+    ret._enable_auto_signals = args.enable_auto_signals
+
+    -- To catch all changes, a proxy is required
+    if args.enable_auto_signals then
+        ret._class = ret._class and setmetatable({}, {__index = args.class}) or {}
+    end
+
+    if args.enable_properties then
+        -- Check got existing get_xxxx and set_xxxx
+        mt.__index    = get_miss
+        mt.__newindex = set_miss
+    elseif args.class then
+        -- Use the class table a miss handler
+        mt.__index = ret._class
+    end
+
+    return setmetatable(ret, mt)
 end
 
 function object.mt.__call(_, ...)

spec/gears/object_spec.lua

@@ -161,6 +161,64 @@ describe("gears.object", function()
         assert.is_true(finalized)
         obj:emit_signal("signal")
     end)
+
+    it("dynamic property disabled", function()
+        local class = {}
+        function class:get_foo() return "bar" end
+        function class:set_foo() end
+
+        local obj2 = object{class=class}
+
+        obj2.foo = 42
+
+        assert.is_true(obj2.foo == 42)
+    end)
+
+    it("dynamic property disabled", function()
+        local class = {}
+        function class:get_foo() return "bar" end
+        function class:set_foo() end
+
+        local obj2 = object{class=class, enable_properties = true}
+
+        obj2.foo = 42
+
+        assert.is_true(obj2.foo == "bar")
+    end)
+
+    it("auto emit disabled", function()
+        local got_it = false
+        obj:add_signal("property::foo")
+        obj:connect_signal("property::foo", function() got_it=true end)
+
+        obj.foo = 42
+
+        assert.is_false(got_it)
+    end)
+
+    it("auto emit enabled", function()
+        local got_it = false
+        local obj2 = object{enable_auto_signals=true, enable_properties=true}
+        obj2:add_signal("property::foo")
+        obj2:connect_signal("property::foo", function() got_it=true end)
+
+        obj2.foo = 42
+
+        assert.is_true(got_it)
+    end)
+
+    it("auto emit enabled", function()
+        assert.has.errors(function()
+            local obj2 = object{enable_auto_signals=true, enable_properties=true}
+            obj2.foo = "bar"
+        end)
+    end)
+
+    it("auto emit without dynamic properties", function()
+        assert.has.errors(function()
+            object{enable_auto_signals=true, enable_properties=false}
+        end)
+    end)
 end)
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

tests/examples/text/gears/object/properties.lua

@@ -0,0 +1,55 @@
+local gears = require("gears") --DOC_HIDE
+
+ -- Create a class for this object. It will be used as a backup source for
+ -- methods and acessors. It is also possible to set them diretly on the
+ -- object.
+local class = {}
+ 
+function class:get_foo()
+    print("In get foo", self._foo or "bar")
+    return self._foo or "bar"
+end
+ 
+function class:set_foo(value)
+    print("In set foo", value)
+
+    -- In case it is necessary to bypass the object property system, use
+    -- `rawset`
+    rawset(self, "_foo", value)
+
+    -- When using custom accessors, the signals need to be handled manually
+    self:emit_signal("property::foo", value)
+end
+
+function class:method(a, b, c)
+    print("In a mathod", a, b, c)
+end
+
+local o = gears.object {
+    class               = class,
+    enable_properties   = true,
+    enable_auto_signals = true,
+}
+
+o:add_signal "property::foo"
+
+print(o.foo)
+ 
+o.foo = 42
+ 
+print(o.foo)
+ 
+o:method(1, 2, 3)
+
+ -- Random properties can also be added, the signal will be emited automatically.
+o:add_signal "property::something"
+
+o:connect_signal("property::something", function(obj, value)
+    print("In the connection handler!", obj, value)
+end)
+
+print(o.something)
+ 
+o.something = "a cow"
+ 
+print(o.something)

tests/examples/text/gears/object/signal.lua

@@ -0,0 +1,27 @@
+local gears = require("gears") --DOC_HIDE
+
+local o = gears.object{}
+ 
+ -- Add a new signals to the object. This is used to catch typos
+o:add_signal "my_signal"
+ 
+ -- Function can be attached to signals
+local function slot(obj, a, b, c)
+    print("In slot", obj, a, b, c)
+end
+ 
+o:connect_signal("my_signal", slot)
+ 
+ -- Emit can be done without argument. In that case, the object will be 
+ -- implicitly added as an argument.
+o:emit_signal "my_signal"
+ 
+ -- It is also possible to add as many random arguments are required.
+o:emit_signal("my_signal", "foo", "bar", 42)
+ 
+ -- Finally, to allow the object to be garbage collected (the memory freed), it
+ -- is necessary to disconnect the signal or use `weak_connect_signal`
+o:disconnect_signal("my_signal", slot)
+ 
+ -- This time, the `slot` wont be called as it is no longer connected.
+o:emit_signal "my_signal"

tests/examples/text/template.lua

@@ -0,0 +1,19 @@
+local file_path, _, luacovpath = ...
+
+-- Set the global shims
+-- luacheck: globals awesome root tag screen client mouse drawin
+awesome = require( "awesome" )
+root    = require( "root"    )
+tag     = require( "tag"     )
+screen  = require( "screen"  )
+client  = require( "client"  )
+mouse   = require( "mouse"   )
+drawin  = require( "drawin"  )
+
+-- If luacov is available, use it. Else, do nothing.
+pcall(function()
+    require("luacov.runner")(luacovpath)
+end)
+
+-- Execute the test
+loadfile(file_path)()