+++ /dev/null
---[[
-LuaSocket 2.0.2 license
-Copyright � 2004-2007 Diego Nehab
-
-Permission is hereby granted, free of charge, to any person obtaining a
-copy of this software and associated documentation files (the "Software"),
-to deal in the Software without restriction, including without limitation
-the rights to use, copy, modify, merge, publish, distribute, sublicense,
-and/or sell copies of the Software, and to permit persons to whom the
-Software is furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
-]]--
---[[
- Changes made by LuCI project:
- * Renamed to luci.ltn12 to avoid collisions with luasocket
- * Added inline documentation
-]]--
------------------------------------------------------------------------------
--- LTN12 - Filters, sources, sinks and pumps.
--- LuaSocket toolkit.
--- Author: Diego Nehab
--- RCS ID: $Id$
------------------------------------------------------------------------------
-
------------------------------------------------------------------------------
--- Declare module
------------------------------------------------------------------------------
-local string = require("string")
-local table = require("table")
-local base = _G
-
---- Diego Nehab's LTN12 - Filters, sources, sinks and pumps.
--- See http://lua-users.org/wiki/FiltersSourcesAndSinks for design concepts
-module("luci.ltn12")
-
-filter = {}
-source = {}
-sink = {}
-pump = {}
-
--- 2048 seems to be better in windows...
-BLOCKSIZE = 2048
-_VERSION = "LTN12 1.0.1"
-
------------------------------------------------------------------------------
--- Filter stuff
------------------------------------------------------------------------------
-
---- LTN12 Filter constructors
--- @class module
--- @name luci.ltn12.filter
-
---- Return a high level filter that cycles a low-level filter
--- by passing it each chunk and updating a context between calls.
--- @param low Low-level filter
--- @param ctx Context
--- @param extra Extra argument passed to the low-level filter
--- @return LTN12 filter
-function filter.cycle(low, ctx, extra)
- base.assert(low)
- return function(chunk)
- local ret
- ret, ctx = low(ctx, chunk, extra)
- return ret
- end
-end
-
---- Chain a bunch of filters together.
--- (thanks to Wim Couwenberg)
--- @param ... filters to be chained
--- @return LTN12 filter
-function filter.chain(...)
- local n = table.getn(arg)
- local top, index = 1, 1
- local retry = ""
- return function(chunk)
- retry = chunk and retry
- while true do
- if index == top then
- chunk = arg[index](chunk)
- if chunk == "" or top == n then return chunk
- elseif chunk then index = index + 1
- else
- top = top+1
- index = top
- end
- else
- chunk = arg[index](chunk or "")
- if chunk == "" then
- index = index - 1
- chunk = retry
- elseif chunk then
- if index == n then return chunk
- else index = index + 1 end
- else base.error("filter returned inappropriate nil") end
- end
- end
- end
-end
-
------------------------------------------------------------------------------
--- Source stuff
------------------------------------------------------------------------------
-
---- LTN12 Source constructors
--- @class module
--- @name luci.ltn12.source
-
--- create an empty source
-local function empty()
- return nil
-end
-
---- Create an empty source.
--- @return LTN12 source
-function source.empty()
- return empty
-end
-
---- Return a source that just outputs an error.
--- @param err Error object
--- @return LTN12 source
-function source.error(err)
- return function()
- return nil, err
- end
-end
-
---- Create a file source.
--- @param handle File handle ready for reading
--- @param io_err IO error object
--- @return LTN12 source
-function source.file(handle, io_err)
- if handle then
- return function()
- local chunk = handle:read(BLOCKSIZE)
- if not chunk then handle:close() end
- return chunk
- end
- else return source.error(io_err or "unable to open file") end
-end
-
---- Turn a fancy source into a simple source.
--- @param src fancy source
--- @return LTN12 source
-function source.simplify(src)
- base.assert(src)
- return function()
- local chunk, err_or_new = src()
- src = err_or_new or src
- if not chunk then return nil, err_or_new
- else return chunk end
- end
-end
-
---- Create a string source.
--- @param s Data
--- @return LTN12 source
-function source.string(s)
- if s then
- local i = 1
- return function()
- local chunk = string.sub(s, i, i+BLOCKSIZE-1)
- i = i + BLOCKSIZE
- if chunk ~= "" then return chunk
- else return nil end
- end
- else return source.empty() end
-end
-
---- Creates rewindable source.
--- @param src LTN12 source to be made rewindable
--- @return LTN12 source
-function source.rewind(src)
- base.assert(src)
- local t = {}
- return function(chunk)
- if not chunk then
- chunk = table.remove(t)
- if not chunk then return src()
- else return chunk end
- else
- t[#t+1] = chunk
- end
- end
-end
-
---- Chain a source and a filter together.
--- @param src LTN12 source
--- @param f LTN12 filter
--- @return LTN12 source
-function source.chain(src, f)
- base.assert(src and f)
- local last_in, last_out = "", ""
- local state = "feeding"
- local err
- return function()
- if not last_out then
- base.error('source is empty!', 2)
- end
- while true do
- if state == "feeding" then
- last_in, err = src()
- if err then return nil, err end
- last_out = f(last_in)
- if not last_out then
- if last_in then
- base.error('filter returned inappropriate nil')
- else
- return nil
- end
- elseif last_out ~= "" then
- state = "eating"
- if last_in then last_in = "" end
- return last_out
- end
- else
- last_out = f(last_in)
- if last_out == "" then
- if last_in == "" then
- state = "feeding"
- else
- base.error('filter returned ""')
- end
- elseif not last_out then
- if last_in then
- base.error('filter returned inappropriate nil')
- else
- return nil
- end
- else
- return last_out
- end
- end
- end
- end
-end
-
---- Create a source that produces contents of several sources.
--- Sources will be used one after the other, as if they were concatenated
--- (thanks to Wim Couwenberg)
--- @param ... LTN12 sources
--- @return LTN12 source
-function source.cat(...)
- local src = table.remove(arg, 1)
- return function()
- while src do
- local chunk, err = src()
- if chunk then return chunk end
- if err then return nil, err end
- src = table.remove(arg, 1)
- end
- end
-end
-
------------------------------------------------------------------------------
--- Sink stuff
------------------------------------------------------------------------------
-
---- LTN12 sink constructors
--- @class module
--- @name luci.ltn12.sink
-
---- Create a sink that stores into a table.
--- @param t output table to store into
--- @return LTN12 sink
-function sink.table(t)
- t = t or {}
- local f = function(chunk, err)
- if chunk then t[#t+1] = chunk end
- return 1
- end
- return f, t
-end
-
---- Turn a fancy sink into a simple sink.
--- @param snk fancy sink
--- @return LTN12 sink
-function sink.simplify(snk)
- base.assert(snk)
- return function(chunk, err)
- local ret, err_or_new = snk(chunk, err)
- if not ret then return nil, err_or_new end
- snk = err_or_new or snk
- return 1
- end
-end
-
---- Create a file sink.
--- @param handle file handle to write to
--- @param io_err IO error
--- @return LTN12 sink
-function sink.file(handle, io_err)
- if handle then
- return function(chunk, err)
- if not chunk then
- handle:close()
- return 1
- else return handle:write(chunk) end
- end
- else return sink.error(io_err or "unable to open file") end
-end
-
--- creates a sink that discards data
-local function null()
- return 1
-end
-
---- Create a sink that discards data.
--- @return LTN12 sink
-function sink.null()
- return null
-end
-
---- Create a sink that just returns an error.
--- @param err Error object
--- @return LTN12 sink
-function sink.error(err)
- return function()
- return nil, err
- end
-end
-
---- Chain a sink with a filter.
--- @param f LTN12 filter
--- @param snk LTN12 sink
--- @return LTN12 sink
-function sink.chain(f, snk)
- base.assert(f and snk)
- return function(chunk, err)
- if chunk ~= "" then
- local filtered = f(chunk)
- local done = chunk and ""
- while true do
- local ret, snkerr = snk(filtered, err)
- if not ret then return nil, snkerr end
- if filtered == done then return 1 end
- filtered = f(done)
- end
- else return 1 end
- end
-end
-
------------------------------------------------------------------------------
--- Pump stuff
------------------------------------------------------------------------------
-
---- LTN12 pump functions
--- @class module
--- @name luci.ltn12.pump
-
---- Pump one chunk from the source to the sink.
--- @param src LTN12 source
--- @param snk LTN12 sink
--- @return Chunk of data or nil if an error occured
--- @return Error object
-function pump.step(src, snk)
- local chunk, src_err = src()
- local ret, snk_err = snk(chunk, src_err)
- if chunk and ret then return 1
- else return nil, src_err or snk_err end
-end
-
---- Pump all data from a source to a sink, using a step function.
--- @param src LTN12 source
--- @param snk LTN12 sink
--- @param step step function (optional)
--- @return 1 if the operation succeeded otherwise nil
--- @return Error object
-function pump.all(src, snk, step)
- base.assert(src and snk)
- step = step or pump.step
- while true do
- local ret, err = step(src, snk)
- if not ret then
- if err then return nil, err
- else return 1 end
- end
- end
-end
-
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