From ea84563bb430bee503da323036a7bd0a17f37992 Mon Sep 17 00:00:00 2001
From: Mikayla Fischler <mikayla@ky8.io>
Date: Thu, 10 Mar 2022 14:09:21 -0500
Subject: [PATCH] added protected peripheral manager and file system logger

---
 scada-common/log.lua |  43 +++++++++++++++
 scada-common/ppm.lua | 127 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 170 insertions(+)
 create mode 100644 scada-common/log.lua
 create mode 100644 scada-common/ppm.lua

diff --git a/scada-common/log.lua b/scada-common/log.lua
new file mode 100644
index 0000000..29fc688
--- /dev/null
+++ b/scada-common/log.lua
@@ -0,0 +1,43 @@
+--
+-- File System Logger
+--
+
+-- we use extra short abbreviations since computer craft screens are very small
+-- underscores are used since some of these names are used elsewhere (e.g. 'debug' is a lua table)
+
+local file_handle = fs.open("/log.txt", "a")
+
+local _log = function (msg)
+    local stamped = os.date("[%c] ") .. msg
+    file_handle.writeLine(stamped)
+    file_handle.flush()
+end
+
+function _debug(msg, trace)
+    local dbg_info = ""
+    
+    if trace then
+        local name = ""
+
+        if debug.getinfo(2).name ~= nil then
+            name = ":" .. debug.getinfo(2).name .. "():"
+        end
+        
+        dbg_info = debug.getinfo(2).short_src .. ":" .. name .. 
+            debug.getinfo(2).currentline .. " > "
+    end
+
+    _log("[DBG] " .. dbg_info .. msg)
+end
+
+function _warning(msg)
+    _log("[WRN] " .. msg)
+end
+
+function _error(msg)
+    _log("[ERR] " .. msg)
+end
+
+function _fatal(msg)
+    _log("[FTL] " .. msg)
+end
diff --git a/scada-common/ppm.lua b/scada-common/ppm.lua
new file mode 100644
index 0000000..32b05ae
--- /dev/null
+++ b/scada-common/ppm.lua
@@ -0,0 +1,127 @@
+-- #REQUIRES log.lua
+
+--
+-- Protected Peripheral Manager
+--
+
+function ppm()
+    local self = {
+        mounts = {}
+    }
+
+    -- wrap peripheral calls with lua protected call
+    -- ex. reason: we don't want a disconnect to crash the program before a SCRAM
+    local peri_init = function (device)
+        for key, func in pairs(device) do
+            device[key] = function (...)
+                local status, result = pcall(func, ...)
+
+                if status then
+                    return result
+                else
+                    -- function failed
+                    log._error("protected " .. key .. "() -> " .. result)
+                    return nil
+                end
+            end
+        end
+    end
+
+    -- mount all available peripherals (clears mounts first)
+    local mount_all = function ()
+        local ifaces = peripheral.getNames()
+
+        self.mounts = {}
+
+        for i = 1, #ifaces do
+            local pm_dev = peripheral.wrap(ifaces[i])
+            peri_init(pm_dev)
+            self.mounts[ifaces[i]] = { peripheral.getType(ifaces[i]), pm_dev }
+        end
+    end
+
+    -- mount a particular device
+    local mount = function (name)
+        local ifaces = peripheral.getNames()
+        local pm_dev = nil
+
+        for i = 1, #ifaces do
+            if name == peripheral.getType(ifaces[i]) then
+                pm_dev = peripheral.wrap(ifaces[i])
+                peri_init(pm_dev)
+
+                self.mounts[ifaces[i]] = { 
+                    type = peripheral.getType(ifaces[i]), 
+                    device = pm_dev 
+                }
+                break
+            end
+        end
+ 
+        return pm_dev
+    end
+
+    -- handle peripheral_detach event
+    local unmount_handler = function (iface)
+        -- what got disconnected?
+        local lost_dev = self.mounts[iface]
+        local type = lost_dev.type
+        
+        log._warning("PMGR: lost device " .. type .. " mounted to " .. iface)
+
+        return self.mounts[iface]
+    end
+
+    -- list all available peripherals
+    local list_avail = function ()
+        return peripheral.getNames()
+    end
+
+    -- list mounted peripherals
+    local list_mounts = function ()
+        return self.mounts
+    end
+
+    -- get a mounted peripheral by side/interface
+    local get_periph = function (iface)
+        return self.mounts[iface].device
+    end
+
+    -- get a mounted peripheral by type
+    local get_device = function (name)
+        local device = nil
+
+        for side, data in pairs(self.mounts) do
+            if data.type == name then
+                device = data.device
+                break
+            end
+        end
+        
+        return device
+    end
+
+    -- list all connected monitors
+    local list_monitors = function ()
+        local monitors = {}
+
+        for side, data in pairs(self.mounts) do
+            if data.type == "monitor" then
+                monitors[side] = data.device
+            end
+        end
+
+        return monitors
+    end
+
+    return {
+        mount_all = mount_all,
+        mount = mount,
+        umount = unmount_handler,
+        list_avail = list_avail,
+        list_mounts = list_mounts,
+        get_periph = get_periph,
+        get_device = get_device,
+        list_monitors = list_monitors
+    }
+end