mirror of
https://github.com/koreader/koreader
synced 2024-11-18 03:25:46 +00:00
55 lines
1.7 KiB
Lua
55 lines
1.7 KiB
Lua
--[[
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"Global" LRU cache used by Document & friends.
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--]]
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local Cache = require("cache")
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local CanvasContext = require("document/canvascontext")
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local DataStorage = require("datastorage")
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local logger = require("logger")
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local function calcCacheMemSize()
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local min = DGLOBAL_CACHE_SIZE_MINIMUM
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local max = DGLOBAL_CACHE_SIZE_MAXIMUM
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local calc = Cache:_calcFreeMem() * (DGLOBAL_CACHE_FREE_PROPORTION or 0)
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return math.min(max, math.max(min, calc))
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end
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local cache_size = calcCacheMemSize()
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local function computeCacheSize()
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local mb_size = cache_size / 1024 / 1024
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-- If we end up with a not entirely ridiculous cache size, use that...
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if mb_size >= 8 then
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logger.dbg(string.format("Allocating a %dMB budget for the global document cache", mb_size))
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return cache_size
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else
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return nil
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end
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end
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local function computeCacheSlots()
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local mb_size = cache_size / 1024 / 1024
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--- ...otherwise, effectively disable the cache by making it single slot...
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if mb_size < 8 then
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logger.dbg(string.format("Setting up a minimal single slot global document cache"))
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return 1
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else
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return nil
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end
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end
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local DocCache = Cache:new{
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slots = computeCacheSlots(),
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size = computeCacheSize(),
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-- Average item size is a screen's worth of bitmap, mixed with a few much smaller tables (pgdim, pglinks, etc.), hence the / 3
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avg_itemsize = math.floor(CanvasContext:getWidth() * CanvasContext:getHeight() * (CanvasContext.is_color_rendering_enabled and 4 or 1) / 3),
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-- Rely on CacheItem's eviction callback to free resources *immediately* on eviction.
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enable_eviction_cb = true,
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disk_cache = true,
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cache_path = DataStorage:getDataDir() .. "/cache/",
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}
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return DocCache
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