#497 unload apps when required connections are lost

pocket/pocket.lua

@@ -102,7 +102,8 @@ pocket.APP_ID = APP_ID
 ---@param render_queue mqueue
 function pocket.init_nav(render_queue)
     local self = {
-        pane = nil, ---@type graphics_element
+        pane = nil,    ---@type graphics_element
+        sidebar = nil, ---@type graphics_element
         apps = {},
         containers = {},
         help_map = {},
@@ -117,23 +118,22 @@ function pocket.init_nav(render_queue)
 
     -- set the root pane element to switch between apps with
     ---@param root_pane graphics_element
-    function nav.set_pane(root_pane)
+    function nav.set_pane(root_pane) self.pane = root_pane end
-        self.pane = root_pane
-    end
 
-    function nav.set_sidebar(sidebar)
+    -- link sidebar element
-        self.sidebar = sidebar
+    ---@param sidebar graphics_element
-    end
+    function nav.set_sidebar(sidebar) self.sidebar = sidebar end
 
     -- register an app
     ---@param app_id POCKET_APP_ID app ID
     ---@param container graphics_element element that contains this app (usually a Div)
     ---@param pane graphics_element? multipane if this is a simple paned app, then nav_to must be a number
-    function nav.register_app(app_id, container, pane)
+    ---@param require_sv boolean? true or false/nil otherwise to specifiy if this app should be unloaded when the supervisor connection is lost
+    ---@param require_api boolean? true or false/nil otherwise to specifiy if this app should be unloaded when the api connection is lost
+    function nav.register_app(app_id, container, pane, require_sv, require_api)
         ---@class pocket_app
         local app = {
             loaded = false,
-            load = nil,
             cur_page = nil, ---@type nav_tree_page
             pane = pane,
             paned_pages = {},
@@ -141,6 +141,11 @@ function pocket.init_nav(render_queue)
         }
 
         app.load = function () app.loaded = true end
+        app.unload = function () app.loaded = false end
+
+        -- check which connections this requires
+        ---@return boolean requires_sv, boolean requires_api
+        function app.check_requires() return require_sv or false, require_api or false end
 
         -- delayed set of the pane if it wasn't ready at the start
         ---@param root_pane graphics_element multipane
@@ -155,13 +160,22 @@ function pocket.init_nav(render_queue)
 
         -- function to run on initial load into memory
         ---@param on_load function callback
-        function app.set_on_load(on_load)
+        function app.set_load(on_load)
             app.load = function ()
                 on_load()
                 app.loaded = true
             end
         end
 
+        -- function to run to close out the app
+        ---@param on_unload function callback
+        function app.set_unload(on_unload)
+            app.unload = function ()
+                on_unload()
+                app.loaded = false
+            end
+        end
+
         -- if a pane was provided, this will switch between numbered pages
         ---@param idx integer page index
         function app.switcher(idx)
@@ -207,6 +221,12 @@ function pocket.init_nav(render_queue)
             return page
         end
 
+        -- delete paned pages and clear the current page
+        function app.delete_pages()
+            app.paned_pages = {}
+            app.cur_page = nil
+        end
+
         -- get the currently active page
         function app.get_current_page() return app.cur_page end
 
@@ -251,6 +271,22 @@ function pocket.init_nav(render_queue)
         self.apps[app_id].load()
     end
 
+    -- unload api-dependent apps
+    function nav.unload_api()
+        for _, app in pairs(self.apps) do
+            local _, api = app.check_requires()
+            if app.loaded and api then app.unload() end
+        end
+    end
+
+    -- unload supervisor-dependent apps
+    function nav.unload_sv()
+        for _, app in pairs(self.apps) do
+            local sv, _ = app.check_requires()
+            if app.loaded and sv then app.unload() end
+        end
+    end
+
     -- get a list of the app containers (usually Div elements)
     function nav.get_containers() return self.containers end
 
@@ -300,7 +336,8 @@ end
 ---@param nic nic network interface device
 ---@param sv_watchdog watchdog
 ---@param api_watchdog watchdog
-function pocket.comms(version, nic, sv_watchdog, api_watchdog)
+---@param nav pocket_nav
+function pocket.comms(version, nic, sv_watchdog, api_watchdog, nav)
     local self = {
         sv = {
             linked = false,
@@ -399,6 +436,7 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog)
     -- close connection to the supervisor
     function public.close_sv()
         sv_watchdog.cancel()
+        nav.unload_sv()
         self.sv.linked = false
         self.sv.r_seq_num = nil
         self.sv.addr = comms.BROADCAST
@@ -408,6 +446,7 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog)
     -- close connection to coordinator API server
     function public.close_api()
         api_watchdog.cancel()
+        nav.unload_api()
         self.api.linked = false
         self.api.r_seq_num = nil
         self.api.addr = comms.BROADCAST
@@ -589,6 +628,7 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog)
                         elseif packet.type == MGMT_TYPE.CLOSE then
                             -- handle session close
                             api_watchdog.cancel()
+                            nav.unload_api()
                             self.api.linked = false
                             self.api.r_seq_num = nil
                             self.api.addr = comms.BROADCAST
@@ -694,6 +734,7 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog)
                         elseif packet.type == MGMT_TYPE.CLOSE then
                             -- handle session close
                             sv_watchdog.cancel()
+                            nav.unload_sv()
                             self.sv.linked = false
                             self.sv.r_seq_num = nil
                             self.sv.addr = comms.BROADCAST

pocket/startup.lua

@@ -122,6 +122,8 @@ local function main()
     -- setup system
     ----------------------------------------
 
+    smem_sys.nav = pocket.init_nav(__shared_memory.q.mq_render)
+
     -- message authentication init
     if type(config.AuthKey) == "string" and string.len(config.AuthKey) > 0 then
         network.init_mac(config.AuthKey)
@@ -145,11 +147,10 @@ local function main()
 
     -- create network interface then setup comms
     smem_sys.nic = network.nic(smem_dev.modem)
-    smem_sys.pocket_comms = pocket.comms(POCKET_VERSION, smem_sys.nic, smem_sys.sv_wd, smem_sys.api_wd)
+    smem_sys.pocket_comms = pocket.comms(POCKET_VERSION, smem_sys.nic, smem_sys.sv_wd, smem_sys.api_wd, smem_sys.nav)
     log.debug("startup> comms init")
 
-    -- init nav and I/O handler
+    -- init I/O control
-    smem_sys.nav = pocket.init_nav(__shared_memory.q.mq_render)
     iocontrol.init_core(smem_sys.pocket_comms, smem_sys.nav)
 
     ----------------------------------------

pocket/threads.lua

@@ -1,13 +1,13 @@
-local log       = require("scada-common.log")
+local log      = require("scada-common.log")
-local mqueue    = require("scada-common.mqueue")
+local mqueue   = require("scada-common.mqueue")
-local ppm       = require("scada-common.ppm")
+local ppm      = require("scada-common.ppm")
-local tcd       = require("scada-common.tcd")
+local tcd      = require("scada-common.tcd")
-local util      = require("scada-common.util")
+local util     = require("scada-common.util")
 
-local pocket    = require("pocket.pocket")
+local pocket   = require("pocket.pocket")
-local renderer  = require("pocket.renderer")
+local renderer = require("pocket.renderer")
 
-local core      = require("graphics.core")
+local core     = require("graphics.core")
 
 local threads = {}
 

pocket/ui/apps/guide.lua

@@ -55,16 +55,21 @@ local function new_view(root)
     local btn_active = cpair(colors.white, colors.black)
     local btn_disable = cpair(colors.gray, colors.black)
 
-    local list = {
+    app.set_sidebar({{ label = " # ", tall = true, color = core.cpair(colors.black, colors.green), callback = function () db.nav.open_app(APP_ID.ROOT) end }})
-        { label = " # ", tall = true, color = core.cpair(colors.black, colors.green), callback = function () db.nav.open_app(APP_ID.ROOT) end },
-        { label = " \x14 ", color = core.cpair(colors.black, colors.cyan), callback = function () app.switcher(1) end },
-        { label = "__?", color = core.cpair(colors.black, colors.lightGray), callback = function () app.switcher(2) end }
-    }
 
-    app.set_sidebar(list)
+    local page_div = nil ---@type nil|graphics_element
 
+    -- load the app (create the elements)
     local function load()
-        local page_div = Div{parent=main,y=2}
+        local list = {
+            { label = " # ", tall = true, color = core.cpair(colors.black, colors.green), callback = function () db.nav.open_app(APP_ID.ROOT) end },
+            { label = " \x14 ", color = core.cpair(colors.black, colors.cyan), callback = function () app.switcher(1) end },
+            { label = "__?", color = core.cpair(colors.black, colors.lightGray), callback = function () app.switcher(2) end }
+        }
+
+        app.set_sidebar(list)
+
+        page_div = Div{parent=main,y=2}
         local p_width = page_div.get_width() - 2
 
         local main_page = app.new_page(nil, 1)
@@ -219,7 +224,22 @@ local function new_view(root)
         load_pane.set_value(2)
     end
 
-    app.set_on_load(load)
+    -- delete the elements and switch back to the loading screen
+    local function unload()
+        if page_div then
+            page_div.delete()
+            page_div = nil
+        end
+
+        app.set_sidebar({ { label = " # ", tall = true, color = core.cpair(colors.black, colors.green), callback = function () db.nav.open_app(APP_ID.ROOT) end } })
+        app.delete_pages()
+
+        -- show loading screen
+        load_pane.set_value(1)
+    end
+
+    app.set_load(load)
+    app.set_unload(unload)
 
     return main
 end

pocket/ui/apps/unit.lua

@@ -56,7 +56,7 @@ local function new_view(root)
 
     local frame = Div{parent=root,x=1,y=1}
 
-    local app = db.nav.register_app(APP_ID.UNITS, frame)
+    local app = db.nav.register_app(APP_ID.UNITS, frame, nil, false, true)
 
     local load_div = Div{parent=frame,x=1,y=1}
     local main = Div{parent=frame,x=1,y=1}
@@ -66,13 +66,15 @@ local function new_view(root)
 
     local load_pane = MultiPane{parent=main,x=1,y=1,panes={load_div,main}}
 
-    TextBox{parent=main,y=4,text="Loading...",height=1,alignment=ALIGN.CENTER}
+    app.set_sidebar({ { label = " # ", tall = true, color = core.cpair(colors.black, colors.green), callback = function () db.nav.open_app(APP_ID.ROOT) end } })
 
     local btn_fg_bg = cpair(colors.yellow, colors.black)
     local btn_active = cpair(colors.white, colors.black)
 
     local nav_links = {}
+    local page_div = nil ---@type nil|graphics_element
 
+    -- set sidebar to display unit-specific fields based on a specified unit
     local function set_sidebar(id)
         local unit = db.units[id] ---@type pioctl_unit
 
@@ -96,8 +98,9 @@ local function new_view(root)
         app.set_sidebar(list)
     end
 
+    -- load the app (create the elements)
     local function load()
-        local page_div = Div{parent=main,y=2,width=main.get_width()}
+        page_div = Div{parent=main,y=2,width=main.get_width()}
 
         local panes = {}
 
@@ -376,7 +379,22 @@ local function new_view(root)
         load_pane.set_value(2)
     end
 
-    app.set_on_load(load)
+    -- delete the elements and switch back to the loading screen
+    local function unload()
+        if page_div then
+            page_div.delete()
+            page_div = nil
+        end
+
+        app.set_sidebar({ { label = " # ", tall = true, color = core.cpair(colors.black, colors.green), callback = function () db.nav.open_app(APP_ID.ROOT) end } })
+        app.delete_pages()
+
+        -- show loading screen
+        load_pane.set_value(1)
+    end
+
+    app.set_load(load)
+    app.set_unload(unload)
 
     return main
 end