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https://github.com/koreader/koreader.git
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e503cc4b9c
* implements a Provider singleton, to be used by thirdparty plugins * exporter: support for thirdparty providers * splits plugin loading into two steps: discovery and load 1. get a list of all candidate plugins to load for the different paths 2. sort providers before on the rest of them and try to load them
93 lines
2.0 KiB
Lua
93 lines
2.0 KiB
Lua
--[[
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Provider is a singleton that holds thirdparty implementations for features.
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To be used on plugins, prefixed with "provider-", that implement specific feature APIs.
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]]--
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local util = require("util")
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local function aTable(t)
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if type(t) ~= "table" then
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return {}
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end
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return t
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end
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local Provider = {
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features = {
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["exporter"] = {},
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},
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}
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function Provider:_isValidFeature(s)
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return self.features[s] ~= nil
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end
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--[[--
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Registers an implementation of a feature.
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@param feature string that identifies the feature
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@param name string that identifies the provider
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@param impl table with implementation details
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@treturn bool registered
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]]
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function Provider:register(feature, name, impl)
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if type(name) ~= "string" or type(feature) ~= "string" or type(impl) ~= "table" then
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return false
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end
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if self:_isValidFeature(feature) then
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self.features[feature][name] = impl
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return true
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end
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return false
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end
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--[[--
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Unregisters an implementation of a feature.
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@param feature string feature identifier
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@param name string provider identifier
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@treturn bool unregistered
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]]
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function Provider:unregister(feature, name)
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if type(name) ~= "string" or type(feature) ~= "string" then
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return false
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end
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if self:_isValidFeature(feature) then
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self.features[feature][name] = nil
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return true
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end
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return false
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end
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--[[--
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Counts providers for a given feature
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@param feature string feature identifier
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@treturn int number
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]]
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function Provider:size(feature)
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local count = 0
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if self:_isValidFeature(feature) then
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count = util.tableSize(aTable(self.features[feature]))
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end
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return count
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end
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--[[--
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Get providers for a given feature
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@param feature string feature identifier
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@treturn table provider/implementation k/v pairs.
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]]
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function Provider:getProvidersTable(feature)
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if self:_isValidFeature(feature) then
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return aTable(self.features[feature])
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end
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return aTable()
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end
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return Provider
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