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koreader/frontend/ui/message/streammessagequeue.lua
2016-02-15 22:34:28 -08:00

90 lines
2.9 KiB
Lua

local ffi = require("ffi")
local DEBUG = require("dbg")
local MessageQueue = require("ui/message/messagequeue")
local _ = require("ffi/zeromq_h")
local zmq = ffi.load("libs/libzmq.so.4")
local czmq = ffi.load("libs/libczmq.so.1")
local StreamMessageQueue = MessageQueue:new{
host = nil,
port = nil,
}
function StreamMessageQueue:start()
self.context = czmq.zctx_new();
self.socket = czmq.zsocket_new(self.context, ffi.C.ZMQ_STREAM)
self.poller = czmq.zpoller_new(self.socket, nil)
local endpoint = string.format("tcp://%s:%d", self.host, self.port)
DEBUG("connect to endpoint", endpoint)
local rc = czmq.zsocket_connect(self.socket, endpoint)
if rc ~= 0 then
error("cannot connect to " .. endpoint)
end
local id_size = ffi.new("size_t[1]", 256)
local buffer = ffi.new("uint8_t[?]", id_size[0])
-- @todo: check return of zmq_getsockopt
zmq.zmq_getsockopt(self.socket, ffi.C.ZMQ_IDENTITY, buffer, id_size)
self.id = ffi.string(buffer, id_size[0])
DEBUG("id", #self.id, self.id)
end
function StreamMessageQueue:stop()
if self.poller ~= nil then
czmq.zpoller_destroy(ffi.new('zpoller_t *[1]', self.poller))
end
if self.socket ~= nil then
czmq.zsocket_destroy(self.context, self.socket)
end
if self.context ~= nil then
czmq.zctx_destroy(ffi.new('zctx_t *[1]', self.context))
end
end
function StreamMessageQueue:handleZframe(frame)
local size = czmq.zframe_size(frame)
local data = nil
if size > 0 then
local frame_data = czmq.zframe_data(frame)
if frame_data ~= nil then
data = ffi.string(frame_data, size)
end
end
czmq.zframe_destroy(ffi.new('zframe_t *[1]', frame))
return data
end
function StreamMessageQueue:waitEvent()
local data = ""
-- Successive zframes may be tens or hundreds in some cases
-- if they are concatenated in a single loop it may run up memory of the
-- machine. And it did happened when receiving file data from Calibre server.
-- Here we receive only receive 10 packages at most in one waitEvent loop, and
-- call receiveCallback immediately.
local wait_packages = 10
while czmq.zpoller_wait(self.poller, 0) ~= nil and wait_packages > 0 do
local id_frame = czmq.zframe_recv(self.socket)
if id_frame ~= nil then
self:handleZframe(id_frame)
end
local frame = czmq.zframe_recv(self.socket)
if frame ~= nil then
data = data .. (self:handleZframe(frame) or "")
end
wait_packages = wait_packages - 1
end
if self.receiveCallback and data ~= "" then
self.receiveCallback(data)
end
end
function StreamMessageQueue:send(data)
--DEBUG("send", data)
local msg = czmq.zmsg_new()
czmq.zmsg_addmem(msg, self.id, #self.id)
czmq.zmsg_addmem(msg, data, #data)
czmq.zmsg_send(ffi.new('zmsg_t *[1]', msg), self.socket)
end
return StreamMessageQueue