first commit

src/callbacks.jl

@@ -0,0 +1,84 @@
+"""
+struct MessageCB with fields
+* topic:: String
+* payload::Vector{UInt8}
+
+A struct containing incoming message information and payload.
+"""
+struct MessageCB
+    topic::String
+    payload::Vector{UInt8}
+end
+
+"""
+struct ConnectionCB with fields
+* clientptr::Ptr
+* val::UInt8
+* returncode::Cint
+
+The clientptr contains the ptr of the client that connected or disconnected.
+This allows to distinguish between clients.
+val is 0 on disconnect and 1 on connect.
+returncode is the MQTT return code which can be used to identify, e.g., the reason for a disconnect.
+"""
+struct ConnectionCB
+    clientptr::Ptr{Cmosquitto}
+    val::UInt8
+    returncode::Cint
+end
+
+
+const messages_channel = Channel{MessageCB}(20)
+const connect_channel = Channel{ConnectionCB}(5)
+
+"""
+    get_messages_channel()
+
+Returns the channel to which received messages are sent. The channel is a Channel{MessageCB}(20).
+See ?Mosquitto.MessageCB for information on the struct
+"""
+get_messages_channel() = messages_channel
+
+"""
+get_connect_channel()
+
+Returns the channel to which event notifications for connections or disconnections are sent. The channel is a Channel{ConnectionCB}(5).
+See ?Mosquitto.ConnectionCB for information on the struct
+"""
+get_connect_channel() = connect_channel
+
+
+# This callback function puts any message on arrival in the channel
+# messages_channel which is a Channel{Mosquitto.Message}(20)
+function callback_message(mos::Ptr{Cmosquitto}, obj::Ptr{Cvoid}, message::Ptr{CMosquittoMessage}) #, clientid::String)
+    # get topic and payload from the message
+    jlmessage = unsafe_load(message)
+    jlpayload = [unsafe_load(jlmessage.payload, i) for i = 1:jlmessage.payloadlen]
+    topic = unsafe_string(jlmessage.topic)
+
+    # put it in the channel for further use
+    if Base.n_avail(messages_channel)>=messages_channel.sz_max
+        take!(messages_channel)
+    end
+    put!(messages_channel, MessageCB(topic, jlpayload))
+    
+    return nothing
+end
+
+
+function callback_connect(mos::Ptr{Cmosquitto}, obj::Ptr{Cvoid}, rc::Cint)
+    if Base.n_avail(connect_channel)>=connect_channel.sz_max
+        take!(connect_channel)
+    end
+    put!( connect_channel, ConnectionCB(mos, one(UInt8), rc ) )
+    return nothing
+end
+
+
+function callback_disconnect(mos::Ptr{Cmosquitto}, obj::Ptr{Cvoid}, rc::Cint)
+    if Base.n_avail(connect_channel)>=connect_channel.sz_max
+        take!(connect_channel)
+    end
+    put!( connect_channel, ConnectionCB(mos, zero(UInt8), rc ) )
+    return nothing
+end