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mirror of https://github.com/koreader/koreader synced 2024-11-18 03:25:46 +00:00
koreader/frontend/ui/hook_container.lua
NiLuJe fadee1f5dc
Clarify our OOP semantics across the codebase (#9586)
Basically:

* Use `extend` for class definitions
* Use `new` for object instantiations

That includes some minor code cleanups along the way:

* Updated `Widget`'s docs to make the semantics clearer.
* Removed `should_restrict_JIT` (it's been dead code since https://github.com/koreader/android-luajit-launcher/pull/283)
* Minor refactoring of LuaSettings/LuaData/LuaDefaults/DocSettings to behave (mostly, they are instantiated via `open` instead of `new`) like everything else and handle inheritance properly (i.e., DocSettings is now a proper LuaSettings subclass).
* Default to `WidgetContainer` instead of `InputContainer` for stuff that doesn't actually setup key/gesture events.
* Ditto for explicit `*Listener` only classes, make sure they're based on `EventListener` instead of something uselessly fancier.
* Unless absolutely necessary, do not store references in class objects, ever; only values. Instead, always store references in instances, to avoid both sneaky inheritance issues, and sneaky GC pinning of stale references.
  * ReaderUI: Fix one such issue with its `active_widgets` array, with critical implications, as it essentially pinned *all* of ReaderUI's modules, including their reference to the `Document` instance (i.e., that was a big-ass leak).
* Terminal: Make sure the shell is killed on plugin teardown.
* InputText: Fix Home/End/Del physical keys to behave sensibly.
* InputContainer/WidgetContainer: If necessary, compute self.dimen at paintTo time (previously, only InputContainers did, which might have had something to do with random widgets unconcerned about input using it as a baseclass instead of WidgetContainer...).
* OverlapGroup: Compute self.dimen at *init* time, because for some reason it needs to do that, but do it directly in OverlapGroup instead of going through a weird WidgetContainer method that it was the sole user of.
* ReaderCropping: Under no circumstances should a Document instance member (here, self.bbox) risk being `nil`ed!
* Kobo: Minor code cleanups.
2022-10-06 02:14:48 +02:00

101 lines
3.2 KiB
Lua

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