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101 lines
3.2 KiB
Lua
101 lines
3.2 KiB
Lua
--[[--
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HookContainer allows listeners to register and unregister a hook for speakers to execute.
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It's an experimental feature: use with cautions, it can easily pin an object in memory and unblock
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GC from recycling the memory.
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]]
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local HookContainer = {}
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function HookContainer:new(o)
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o = o or {}
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function HookContainer:_assertIsValidName(name)
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assert(type(name) == "string")
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assert(string.len(name) > 0)
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end
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function HookContainer:_assertIsValidFunction(func)
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assert(type(func) == "function" or type(func) == "table")
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end
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function HookContainer:_assertIsValidFunctionOrNil(func)
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if func == nil then return end
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self:_assertIsValidFunction(func)
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end
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--- Register a function to name. Must be called with self.
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-- @tparam string name The name of the hook. Can only be an non-empty string.
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-- @tparam function func The function to handle the hook. Can only be a function.
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function HookContainer:register(name, func)
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self:_assertIsValidName(name)
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self:_assertIsValidFunction(func)
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if self[name] == nil then
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self[name] = {}
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end
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table.insert(self[name], func)
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end
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--- Register a widget to name. Must be called with self.
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-- @tparam string name The name of the hook. Can only be an non-empty string.
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-- @tparam table widget The widget to handle the hook. Can only be a table with required functions.
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function HookContainer:registerWidget(name, widget)
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self:_assertIsValidName(name)
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assert(type(widget) == "table")
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-- *That* is the function we actually register and need to unregister later, so keep a ref to it...
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local hook_func = function(args)
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local f = widget["on" .. name]
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self:_assertIsValidFunction(f)
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f(widget, args)
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end
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self:register(name, hook_func)
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local original_close_widget = widget.onCloseWidget
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self:_assertIsValidFunctionOrNil(original_close_widget)
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widget.onCloseWidget = function()
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if original_close_widget then original_close_widget(widget) end
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self:unregister(name, hook_func)
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end
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end
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--- Unregister a function from name. Must be called with self.
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-- @tparam string name The name of the hook. Can only be an non-empty string.
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-- @tparam function func The function to handle the hook. Can only be a function.
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-- @treturn boolean Return true if the function is found and removed, otherwise false.
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function HookContainer:unregister(name, func)
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self:_assertIsValidName(name)
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self:_assertIsValidFunction(func)
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if self[name] == nil then
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return false
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end
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for i, f in ipairs(self[name]) do
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if f == func then
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table.remove(self[name], i)
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return true
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end
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end
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return false
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end
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--- Execute all registered functions of name. Must be called with self.
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-- @tparam string name The name of the hook. Can only be an non-empty string.
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-- @param args Any kind of arguments sending to the functions.
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-- @treturn number The number of functions have been executed.
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function HookContainer:execute(name, args)
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self:_assertIsValidName(name)
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if self[name] == nil or #self[name] == 0 then
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return 0
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end
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for _, f in ipairs(self[name]) do
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f(args)
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end
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return #self[name]
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end
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return HookContainer
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