ConfigHandler: also use global mutex for reading config files

This is necessary for preventing files from being read while they are being written or about to be written by another config handler (which could result in parsing errors, data loss and locking issues)

Author: line0

modules/DependencyControl/ConfigHandler.moon

@@ -114,34 +114,48 @@ Reload your automation scripts to generate a new configuration file.]]
         @file = nil
         return true
 
-    readFile: (file = @file) =>
+    readFile: (file = @file, useLock = true, waitLockTime) =>
+        if useLock
+            time, err = @getLock waitLockTime
+            unless time
+                -- handle\close!
+                return false, errors.failedLock\format "reading", err
+
         mode, file = fileOps.attributes file, "mode"
         if mode == nil
+            @releaseLock! if useLock
             return false, file
         elseif not mode
+            @releaseLock! if useLock
+            @logger\trace traceMsgs.fileNotFound, @file
             return nil
 
         handle, err = io.open file, "r"
         unless handle
+            @releaseLock! if useLock
             return false, err
 
         data = handle\read "*a"
         success, result = pcall json.decode, data
         unless success
+            handle\close!
             -- JSON parse error usually points to a corrupted config file
             -- Rename the broken file to allow generating a new one
             -- so the user can continue his work
-            handle\close!
             @logger\trace errors.jsonDecode, result
             backup = @file .. ".corrupted"
             fileOps.copy @file, backup
             fileOps.remove @file, false, true
+
+            @releaseLock! if useLock
             return false, errors.configCorrupted\format backup
 
+        handle\close!
+        @releaseLock! if useLock
+
         if "table" != type result
             return false, errors.jsonRoot\format type result
 
-        handle\close!
         return result
 
     load: =>
@@ -190,7 +204,7 @@ Reload your automation scripts to generate a new configuration file.]]
         @userConfig = nil
         return @write concertWrite, waitLockTime
 
-    write: (concertWrite, waitLockTime = 5000) =>
+    write: (concertWrite, waitLockTime) =>
         return false, errors.noFile unless @file
 
         -- get a lock to avoid concurrent config file access
@@ -199,8 +213,8 @@ Reload your automation scripts to generate a new configuration file.]]
             return false, errors.failedLockWrite\format err
 
         -- read the config file
-        config, err = @readFile!
-        if err
+        config, err = @readFile @file, false
+        if config == false
             @releaseLock!
             return false, errors.writeFailedRead\format err
         config or= {}
@@ -235,7 +249,7 @@ Reload your automation scripts to generate a new configuration file.]]
 
         return true
 
-    getLock: (waitTimeout, checkInterval = 100) =>
+    getLock: (waitTimeout = 5000, checkInterval = 50) =>
         return 0 if @hasLock
         success = mutex.tryLock!
         if success