diff options
| -rw-r--r-- | util/cache.lua | 75 |
1 files changed, 43 insertions, 32 deletions
diff --git a/util/cache.lua b/util/cache.lua index 32670751..72b74351 100644 --- a/util/cache.lua +++ b/util/cache.lua @@ -1,13 +1,3 @@ -local cache_methods = {}; -local cache_mt = { __index = cache_methods }; - -local function new(size) - size = assert(tonumber(size), "cache size must be a number"); - size = math.floor(size); - assert(size > 0, "cache size must be greater than zero"); - local data = {}; - return setmetatable({ data = data, count = 0, size = size, head = nil, tail = nil }, cache_mt); -end local function _remove(list, m) if m.prev then @@ -16,29 +6,32 @@ local function _remove(list, m) if m.next then m.next.prev = m.prev; end - if list.tail == m then - list.tail = m.prev; + if list._tail == m then + list._tail = m.prev; end - if list.head == m then - list.head = m.next; + if list._head == m then + list._head = m.next; end - list.count = list.count - 1; + list._count = list._count - 1; end local function _insert(list, m) - if list.head then - list.head.prev = m; + if list._head then + list._head.prev = m; end - m.prev, m.next = nil, list.head; - list.head = m; - if not list.tail then - list.tail = m; + m.prev, m.next = nil, list._head; + list._head = m; + if not list._tail then + list._tail = m; end - list.count = list.count + 1; + list._count = list._count + 1; end +local cache_methods = {}; +local cache_mt = { __index = cache_methods }; + function cache_methods:set(k, v) - local m = self.data[k]; + local m = self._data[k]; if m then -- Key already exists if v ~= nil then @@ -49,27 +42,33 @@ function cache_methods:set(k, v) else -- Remove from list _remove(self, m); - self.data[k] = nil; + self._data[k] = nil; end - return; + return true; end -- New key if v == nil then - return; + return true; end -- Check whether we need to remove oldest k/v - if self.count == self.size then - self.data[self.tail.key] = nil; - _remove(self, self.tail); + if self._count == self.size then + local tail = self._tail; + local on_evict = self._on_evict; + if on_evict then + on_evict(tail.key, tail.value); + end + _remove(self, tail); + self._data[tail.key] = nil; end m = { key = k, value = v, prev = nil, next = nil }; - self.data[k] = m; + self._data[k] = m; _insert(self, m); + return true; end function cache_methods:get(k) - local m = self.data[k]; + local m = self._data[k]; if m then return m.value; end @@ -77,7 +76,7 @@ function cache_methods:get(k) end function cache_methods:items() - local m = self.head; + local m = self._head; return function () if not m then return; @@ -88,6 +87,18 @@ function cache_methods:items() end end +function cache_methods:count() + return self._count; +end + +local function new(size, on_evict) + size = assert(tonumber(size), "cache size must be a number"); + size = math.floor(size); + assert(size > 0, "cache size must be greater than zero"); + local data = {}; + return setmetatable({ _data = data, _count = 0, size = size, _head = nil, _tail = nil, _on_evict = on_evict }, cache_mt); +end + return { new = new; } |