Cleanup eye-gouging madness around io.read calls (#7149)

* Don't reinvent the wheel when reading a one-line int or string from sysfs

* Simplify a whole other bunch of read calls

frontend/apps/reader/modules/readerfooter.lua

@@ -290,11 +290,10 @@ local footerTextGeneratorMap = {
         local prefix = symbol_prefix[symbol_type].mem_usage
         local statm = io.open("/proc/self/statm", "r")
         if statm then
-            local infos = statm:read("*all")
+            local dummy, rss = statm:read("*number", "*number")
             statm:close()
-            local rss = infos:match("^%S+ (%S+) ")
             -- we got the nb of 4Kb-pages used, that we convert to Mb
-            rss = math.floor(tonumber(rss) * 4096 / 1024 / 1024)
+            rss = math.floor(rss * 4096 / 1024 / 1024)
             return (prefix .. " %d"):format(rss)
         end
         return ""

frontend/device/cervantes/device.lua

@@ -7,7 +7,7 @@ local function no() return false end
 local function getProductId()
     local ntxinfo_pcb = io.popen("/usr/bin/ntxinfo /dev/mmcblk0 | grep pcb | cut -d ':' -f2", "r")
     if not ntxinfo_pcb then return 0 end
-    local product_id = tonumber(ntxinfo_pcb:read()) or 0
+    local product_id = ntxinfo_pcb:read("*number") or 0
     ntxinfo_pcb:close()
     return product_id
 end
@@ -20,23 +20,10 @@ local function isConnected()
     if not file then return 0 end
 
     -- 0 means not connected, 1 connected
-    local out = file:read("*all")
+    local out = file:read("*number")
     file:close()
 
-    -- strip NaN from file read (ie: line endings, error messages)
-    local carrier
-    if type(out) ~= "number" then
-        carrier = tonumber(out)
-    else
-        carrier = out
-    end
-
-    -- finally return if we're connected or not
-    if type(carrier) == "number" then
-        return carrier
-    else
-        return 0
-    end
+    return out or 0
 end
 
 local function isMassStorageSupported()

frontend/device/cervantes/powerd.lua

@@ -192,7 +192,7 @@ function CervantesPowerD:getCapacityHW()
 end
 
 function CervantesPowerD:isChargingHW()
-    return self:read_str_file(self.status_file) == "Charging\n"
+    return self:read_str_file(self.status_file) == "Charging"
 end
 
 function CervantesPowerD:beforeSuspend()

frontend/device/generic/powerd.lua

@@ -95,20 +95,20 @@ function BasePowerD:turnOnFrontlight()
 end
 
 function BasePowerD:read_int_file(file)
-    local fd =  io.open(file, "r")
+    local fd = io.open(file, "r")
     if fd then
-        local int = fd:read("*all"):match("%d+")
+        local int = fd:read("*number")
         fd:close()
-        return int and tonumber(int) or 0
+        return int or 0
     else
         return 0
     end
 end
 
 function BasePowerD:read_str_file(file)
-    local fd =  io.open(file, "r")
+    local fd = io.open(file, "r")
     if fd then
-        local str = fd:read("*all")
+        local str = fd:read("*line")
         fd:close()
         return str
     else

frontend/device/kindle/device.lua

@@ -678,7 +678,7 @@ function KindleOasis:init()
     -- get rotate dev by EV=d
     local std_out = io.popen("grep -e 'Handlers\\|EV=' /proc/bus/input/devices | grep -B1 'EV=d' | grep -o 'event[0-9]'", "r")
     if std_out then
-        local rotation_dev = std_out:read()
+        local rotation_dev = std_out:read("*line")
         std_out:close()
         if rotation_dev then
             self.input.open("/dev/input/"..rotation_dev)
@@ -752,7 +752,7 @@ function KindleOasis2:init()
     -- Get accelerometer device by looking for EV=d
     local std_out = io.popen("grep -e 'Handlers\\|EV=' /proc/bus/input/devices | grep -B1 'EV=d' | grep -o 'event[0-9]\\{1,2\\}'", "r")
     if std_out then
-        local rotation_dev = std_out:read()
+        local rotation_dev = std_out:read("*line")
         std_out:close()
         if rotation_dev then
             self.input.open("/dev/input/"..rotation_dev)
@@ -790,7 +790,7 @@ function KindlePaperWhite4:init()
     -- So, look for a goodix TS input device (c.f., #5110)...
     local std_out = io.popen("grep -e 'Handlers\\|Name=' /proc/bus/input/devices | grep -A1 'goodix-ts' | grep -o 'event[0-9]'", "r")
     if std_out then
-        local goodix_dev = std_out:read()
+        local goodix_dev = std_out:read("*line")
         std_out:close()
         if goodix_dev then
             self.touch_dev = "/dev/input/" .. goodix_dev
@@ -866,7 +866,7 @@ end
 
 local kindle_sn_fd = io.open("/proc/usid", "r")
 if not kindle_sn_fd then return end
-local kindle_sn = kindle_sn_fd:read()
+local kindle_sn = kindle_sn_fd:read("*line")
 kindle_sn_fd:close()
 -- NOTE: Attempt to sanely differentiate v1 from v2,
 --       c.f., https://github.com/NiLuJe/FBInk/commit/8a1161734b3f5b4461247af461d26987f6f1632e

frontend/device/kindle/powerd.lua

@@ -106,9 +106,9 @@ function KindlePowerD:getCapacityHW()
     else
         local std_out = io.popen("gasgauge-info -c 2>/dev/null", "r")
         if std_out then
-            local result = std_out:read("*all"):match("%d+")
+            local result = std_out:read("*number")
             std_out:close()
-            return result and tonumber(result) or 0
+            return result or 0
         else
             return 0
         end

frontend/device/kobo/device.lua

@@ -495,7 +495,7 @@ function Kobo:getCodeName()
     -- If that fails, run the script ourselves
     if not codename then
         local std_out = io.popen("/bin/kobo_config.sh 2>/dev/null", "r")
-        codename = std_out:read()
+        codename = std_out:read("*line")
         std_out:close()
     end
     return codename
@@ -506,7 +506,7 @@ function Kobo:getFirmwareVersion()
     if not version_file then
         self.firmware_rev = "none"
     end
-    local version_str = version_file:read()
+    local version_str = version_file:read("*line")
     version_file:close()
 
     local i = 0
@@ -527,7 +527,7 @@ local function getProductId()
         if not version_file then
             return "000"
         end
-        local version_str = version_file:read()
+        local version_str = version_file:read("*line")
         version_file:close()
 
         product_id = string.sub(version_str, -3, -1)

frontend/device/kobo/powerd.lua

@@ -318,7 +318,7 @@ function KoboPowerD:getCapacityHW()
 end
 
 function KoboPowerD:isChargingHW()
-    return self:read_str_file(self.is_charging_file) == "Charging\n"
+    return self:read_str_file(self.is_charging_file) == "Charging"
 end
 
 function KoboPowerD:turnOffFrontlightHW()

frontend/device/remarkable/powerd.lua

@@ -19,7 +19,7 @@ function Remarkable_PowerD:getCapacityHW()
 end
 
 function Remarkable_PowerD:isChargingHW()
-    return self:read_str_file(self.status_file) == "Charging\n"
+    return self:read_str_file(self.status_file) == "Charging"
 end
 
 return Remarkable_PowerD

frontend/device/sony-prstux/powerd.lua

@@ -25,7 +25,7 @@ function SonyPRSTUX_PowerD:getCapacityHW()
 end
 
 function SonyPRSTUX_PowerD:isChargingHW()
-    return self:read_str_file(self.status_file) == "Charging\n"
+    return self:read_str_file(self.status_file) == "Charging"
 end
 
 return SonyPRSTUX_PowerD

frontend/ui/network/networklistener.lua

@@ -98,23 +98,11 @@ function NetworkListener:_getTxPackets()
     -- file exists only when Wi-Fi module is loaded.
     if not file then return nil end
 
-    local out = file:read("*all")
+    local tx_packets = file:read("*number")
     file:close()
 
-    -- strip NaN from file read (i.e.,: line endings, error messages)
-    local tx_packets
-    if type(out) ~= "number" then
-        tx_packets = tonumber(out)
-    else
-        tx_packets = out
-    end
-
-    -- finally return it
-    if type(tx_packets) == "number" then
-        return tx_packets
-    else
-        return nil
-    end
+    -- Will be nil if NaN, just like we want it
+    return tx_packets
 end
 
 function NetworkListener:_unscheduleActivityCheck()

frontend/ui/wikipedia.lua

@@ -97,7 +97,7 @@ end
 
 -- Say who we are to Wikipedia (see https://meta.wikimedia.org/wiki/User-Agent_policy)
 local USER_AGENT = T("KOReader/%1 (https://koreader.rocks/) %2",
-    (lfs.attributes("git-rev", "mode") == "file" and io.open("git-rev", "r"):read() or "devel"),
+    (lfs.attributes("git-rev", "mode") == "file" and io.open("git-rev", "r"):read("*line") or "devel"),
     require('socket.http').USERAGENT:gsub(" ", "/") )
 
 -- Codes that getUrlContent may get from requester.request()
@@ -895,7 +895,7 @@ function Wikipedia:createEpub(epub_path, page, lang, with_images)
     --     </guide>
     local koreader_version = "KOReader"
     if lfs.attributes("git-rev", "mode") == "file" then
-        koreader_version = "KOReader "..io.open("git-rev", "r"):read()
+        koreader_version = "KOReader "..io.open("git-rev", "r"):read("*line")
     end
     local content_opf_parts = {}
     -- head

frontend/util.lua

@@ -622,13 +622,8 @@ function util.getFilesystemType(path)
     local mounts = io.open("/proc/mounts", "r")
     if not mounts then return nil end
     local type
-    while true do
-        local line
+    for line in mounts:lines() do
         local mount = {}
-        line = mounts:read()
-        if line == nil then
-            break
-        end
         for param in line:gmatch("%S+") do table.insert(mount, param) end
         if string.match(path, mount[2]) then
             type = mount[3]

frontend/version.lua

@@ -10,7 +10,7 @@ function Version:getCurrentRevision()
     if not self.rev then
         local rev_file = io.open("git-rev", "r")
         if rev_file then
-            self.rev = rev_file:read()
+            self.rev = rev_file:read("*line")
             rev_file:close()
         end
         -- sanity check in case `git describe` failed

plugins/systemstat.koplugin/main.lua

@@ -54,7 +54,7 @@ local function systemInfo()
     do
         local stat = io.open("/proc/stat", "r")
         if stat ~= nil then
-            for line in util.gsplit(stat:read("*all"), "\n", false) do
+            for line in stat:lines() do
                 local t = util.splitToArray(line, " ")
                 if #t >= 5 and string.lower(t[1]) == "cpu" then
                     local n1, n2, n3, n4
@@ -82,7 +82,7 @@ local function systemInfo()
         local meminfo = io.open("/proc/meminfo", "r")
         if meminfo ~= nil then
             result.memory = {}
-            for line in util.gsplit(meminfo:read("*all"), "\n", false) do
+            for line in meminfo:lines() do
                 local t = util.splitToArray(line, " ")
                 if #t >= 2 then
                     if string.lower(t[1]) == "memtotal:" then
@@ -142,7 +142,7 @@ function SystemStat:appendProcessInfo()
     local stat = io.open("/proc/self/stat", "r")
     if stat == nil then return end
 
-    local t = util.splitToArray(stat:read("*all"), " ")
+    local t = util.splitToArray(stat:read("*line"), " ")
     stat:close()
 
     local n1, n2
@@ -197,7 +197,7 @@ function SystemStat:appendStorageInfo()
     if not std_out then return end
 
     self:put({_("Storage information"), ""})
-    for line in util.gsplit(std_out:read("*all"), "\n", false) do
+    for line in std_out:lines() do
         local t = util.splitToArray(line, "\t")
         if #t ~= 4 then
             self:put({_("  Unexpected"), line})

plugins/timesync.koplugin/main.lua

@@ -24,10 +24,9 @@ local TimeSync = WidgetContainer:new{
 local function currentTime()
     local std_out = io.popen("date")
     if std_out then
-        local result = std_out:read("*all")
+        local result = std_out:read("*line")
         std_out:close()
         if result ~= nil then
-            result = result:gsub("\n", "")
             return T(_("New time is %1."), result)
         end
     end

spec/unit/device_spec.lua

@@ -227,7 +227,7 @@ describe("device module", function()
                     }
                 elseif filename == "/sys/class/backlight/max77696-bl/brightness" then
                     return {
-                        read = function() return "12" end,
+                        read = function() return 12 end,
                         close = function() end
                     }
                 else