53 lines
1.6 KiB
Lua
53 lines
1.6 KiB
Lua
---------------------------------------------------------------------------
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-- @author Uli Schlachter
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-- @copyright 2015 Uli Schlachter
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-- @release @AWESOME_VERSION@
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-- @classmod gears.cache
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---------------------------------------------------------------------------
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local select = select
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local setmetatable = setmetatable
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local unpack = unpack or table.unpack
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local cache = {}
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--- Get an entry from the cache, creating it if it's missing.
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-- @param ... Arguments for the creation callback. These are checked against the
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-- cache contents for equality.
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-- @return The entry from the cache
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function cache:get(...)
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local result = self._cache
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for i = 1, select("#", ...) do
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local arg = select(i, ...)
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local next = result[arg]
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if not next then
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next = {}
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result[arg] = next
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end
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result = next
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end
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local ret = result._entry
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if not ret then
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ret = { self._creation_cb(...) }
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result._entry = ret
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end
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return unpack(ret)
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end
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--- Create a new cache object. A cache keeps some data that can be
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-- garbage-collected at any time, but might be useful to keep.
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-- @param creation_cb Callback that is used for creating missing cache entries.
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-- @return A new cache object.
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function cache.new(creation_cb)
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return setmetatable({
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_cache = setmetatable({}, { __mode = "v" }),
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_creation_cb = creation_cb
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}, {
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__index = cache
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})
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end
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return setmetatable(cache, { __call = function(_, ...) return cache.new(...) end })
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-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80
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