Implement listening

Signed-off-by: Rahix <rahix@rahix.de>

bc.lua

@@ -17,16 +17,18 @@ local Message = {
   ListenCancel  = 0x4c535450,
 }
 
-local function query_param(self, v)
+local query_param = {
+  __call=function(self, v)
     return {ty=self.ty, v=v}
-end
+  end,
+}
 local Query = {
   Change        = {ty=0x434847},
   Rising        = {ty=0x524953},
   Falling       = {ty=0x46414c},
-  Equals        = setmetatable({ty=0x455155}, {__call=query_param}),
+  Equals        = setmetatable({ty=0x455155, invalid=true}, query_param),
-  Above         = setmetatable({ty=0x414256}, {__call=query_param}),
+  Above         = setmetatable({ty=0x414256, invalid=true}, query_param),
-  Below         = setmetatable({ty=0x424c4f}, {__call=query_param}),
+  Below         = setmetatable({ty=0x424c4f, invalid=true}, query_param),
 }
 
 -- Network ---------------------------------------------------------------- {{{
@@ -99,12 +101,14 @@ local BaseControl = {
   Network = Network,
 }
 
+-- Lifecycle {{{
 function BaseControl:new(network)
   local self = {
     local_nouns = {},
     local_verbs = {},
     remote_nouns = {},
     remote_verbs = {},
+    listeners = {},
 
     live = false,
     network = network or Network:new(),
@@ -222,6 +226,7 @@ function BaseControl:close()
 
   setmetatable(self, nil)
 end
+-- }}}
 
 -- Nouns {{{
 function BaseControl:has_noun(noun)
@@ -272,7 +277,31 @@ function BaseControl:set(name, value)
     if type(value) == "function" then
       error("\""..name.."\" can't be cast into a verb")
     else
+      local old = self.local_nouns[name]
       self.local_nouns[name] = value
+
+      if self.listeners[name] ~= nil then
+        for id, l in pairs(self.listeners[name]) do
+          if   (l.query.ty == Query.Change.ty and value ~= old)
+            or (l.query.ty == Query.Rising.ty and value > old)
+            or (l.query.ty == Query.Falling.ty and value < old)
+            or (l.query.ty == Query.Equals.ty and value == l.query.v)
+            or (l.query.ty == Query.Above.ty and value > l.query.v)
+            or (l.query.ty == Query.Below.ty and value < l.query.v)
+              then
+            if l.callback ~= nil then
+              l.callback(value)
+            else
+              self.network:send(l.addr, {
+                ty=Message.ListenNotify,
+                noun=name,
+                id=id,
+                value=value,
+              })
+            end
+          end
+        end
+      end
     end
   elseif self.local_verbs[name] ~= nil then
     if type(value) ~= "function" then
@@ -347,6 +376,35 @@ function BaseControl:call_sync(verb, ...)
 end
 -- }}}
 
+-- Listening {{{
+function BaseControl:listen(noun, query, callback)
+  if query.invalid then
+    error("invalid query, forgot a parameter?")
+  end
+  if self.listeners[noun] == nil then
+    self.listeners[noun] = {}
+  end
+  local id = uuid.next()
+  self.listeners[noun][id] = {
+    query=query,
+    callback=callback,
+  }
+  if self.local_nouns[noun] ~= nil then
+    return true
+  elseif self.remote_nouns[noun] ~= nil then
+    self.network:send(self.remote_nouns[noun], {
+      ty=Message.ListenRequest,
+      noun=noun,
+      id=id,
+      query=query,
+    })
+    return true
+  else
+    return false
+  end
+end
+-- }}}
+
 -- Network Handler {{{
 function BaseControl:_network_handler(remote, msg)
   if msg.ty == Message.Hello then
@@ -397,6 +455,20 @@ function BaseControl:_network_handler(remote, msg)
     end
   elseif msg.ty == Message.VerbResponse then
     -- Handled via pull
+  elseif msg.ty == Message.ListenRequest then
+    if self.local_nouns[msg.noun] ~= nil then
+      if self.listeners[msg.noun] == nil then
+        self.listeners[msg.noun] = {}
+      end
+      self.listeners[msg.noun][msg.id] = {
+        query=msg.query,
+        addr=remote,
+      }
+    end
+  elseif msg.ty == Message.ListenNotify then
+    if self.listeners[msg.noun][msg.id] ~= nil then
+      self.listeners[msg.noun][msg.id].callback(msg.value)
+    end
   else
     error("TODO: MessageType Unknown")
   end

network.lua

@@ -36,6 +36,7 @@ function network.send(addr, port, msg)
 
   -- print("Sending from "..current_node.." to "..addr..": "..msg)
   -- print(require("inspect").inspect(active_node))
+
   latest_message[addr] = {
     from=current_node,
     port=port,

tests/listening.lua

@@ -0,0 +1,136 @@
+require("lunit")
+
+local network = require("network")
+local serialization = require("serialization")
+local BaseControl = require("bc")
+
+module("listening", package.seeall, lunit.testcase)
+
+function test_invalid_query()
+  local bc = BaseControl:new()
+  local invalids = {
+    bc.Query.Equals,
+    bc.Query.Above,
+    bc.Query.Below,
+  }
+
+  for _, q in ipairs(invalids) do
+    assert_error_match("invalid", function()
+      bc:listen("invq1", q, function() end)
+    end)
+  end
+end
+
+function test_listen_simple()
+  local bc = BaseControl:new()
+  bc:register("lisimpl1", 1234)
+  bc:finalize()
+
+  local n = 0
+  bc:listen("lisimpl1", bc.Query.Change, function(new)
+    n = n + 1
+  end)
+
+  assert_equal(0, n, "wrong number of listener invokations")
+  bc:set("lisimpl1", 4321)
+  assert_equal(1, n, "wrong number of listener invokations")
+  bc:set("lisimpl1", 42)
+  assert_equal(2, n, "wrong number of listener invokations")
+end
+
+function test_listen_network_simple()
+  local bc1 = BaseControl:new()
+  local addr1 = network.get_scene()
+  bc1:register("lin1", 1234)
+  bc1:finalize()
+
+  local bc2 = BaseControl:new()
+  local addr2 = network.get_scene()
+
+  local tmp, n = 0, 0
+  bc2:listen("lin1", bc1.Query.Change, function(new)
+    assert_equal(tmp, new, "value did not propagate")
+    n = n + 1
+  end)
+
+  network.set_scene(addr1)
+  tmp = 12
+  assert_equal(0, n, "wrong number of listener invokations")
+  bc1:set("lin1", 12)
+  assert_equal(1, n, "wrong number of listener invokations")
+
+  tmp = 16
+  bc1:set("lin1", 16)
+  assert_equal(2, n, "wrong number of listener invokations")
+end
+
+-- Generate testcases for queries
+do
+  local tests = {
+    {name="change", query=BaseControl.Query.Change, pos1=1, neg=1, pos2=2},
+    {name="rising", query=BaseControl.Query.Rising, pos1=1, neg=-1, pos2=1},
+    {name="falling", query=BaseControl.Query.Falling, pos1=-1, neg=1, pos2=-1},
+    {name="equals", query=BaseControl.Query.Equals(123), pos1=123, neg=124, pos2=123},
+    {name="above", query=BaseControl.Query.Above(100), pos1=101, neg=99, pos2=123},
+    {name="below", query=BaseControl.Query.Below(100), pos1=12, neg=124, pos2=23},
+  }
+
+  for _, test in ipairs(tests) do
+    -- Local test
+    listening["test_listen_query_"..test.name] = function()
+      local bc = BaseControl:new()
+      local noun = "lq"..test.name.."1"
+      bc:register(noun, 0)
+      bc:finalize()
+
+      local n = 0
+      bc:listen(noun, test.query, function(new)
+        n = n + 1
+      end)
+
+      assert_equal(0, n, "wrong number of listener invokations")
+      bc:set(noun, test.pos1)
+      assert_equal(1, n, "wrong number of listener invokations")
+      bc:set(noun, test.neg)
+      assert_equal(1, n, "wrong number of listener invokations")
+      bc:set(noun, test.pos2)
+      assert_equal(2, n, "wrong number of listener invokations")
+
+      bc:close()
+    end
+
+    -- Remote test
+    listening["test_listen_network_query_"..test.name] = function()
+      local bc1 = BaseControl:new()
+      local addr1 = network.get_scene()
+      local noun = "lnq"..test.name.."1"
+      bc1:register(noun, 0)
+      bc1:finalize()
+
+      local bc2 = BaseControl:new()
+      local addr2 = network.get_scene()
+
+      local tmp, n = 0, 0
+      bc2:listen(noun, test.query, function(new)
+        assert_equal(tmp, new, "value did not propagate")
+        n = n + 1
+      end)
+
+      network.set_scene(addr1)
+      assert_equal(0, n, "wrong number of listener invokations")
+      tmp = test.pos1
+      bc1:set(noun, test.pos1)
+      assert_equal(1, n, "wrong number of listener invokations")
+      tmp = test.neg
+      bc1:set(noun, test.neg)
+      assert_equal(1, n, "wrong number of listener invokations")
+      tmp = test.pos2
+      bc1:set(noun, test.pos2)
+      assert_equal(2, n, "wrong number of listener invokations")
+
+      bc1:close()
+      network.set_scene(addr2)
+      bc2:close()
+    end
+  end
+end