Refine code changes

* Refine code changes from #2608 based on memory allocation and usage

src/clientSideFiltering.d

@@ -30,6 +30,13 @@ class ClientSideFiltering {
 		this.appConfig = appConfig;
 	}
 	
+	~this() {
+		object.destroy(appConfig);
+		object.destroy(paths);
+		object.destroy(fileMask);
+		object.destroy(directoryMask);
+	}
+	
 	// Initialise the required items
 	bool initialise() {
 		// Log what is being done

src/config.d

@@ -682,11 +682,21 @@ class ApplicationConfig {
 		}
 		
 		auto file = File(filename, "r");
-		scope(exit) file.close();
-		scope(failure) file.close();
-
+		string lineBuffer;
+		scope(exit) {
+			file.close();
+			object.destroy(file);
+			object.destroy(lineBuffer);
+		}
+		
+		scope(failure) {
+			file.close();
+			object.destroy(file);
+			object.destroy(lineBuffer);
+		}
+		
 		foreach (line; file.byLine()) {
-			string lineBuffer = stripLeft(line).to!string;
+			lineBuffer = stripLeft(line).to!string;
 			if (lineBuffer.empty || lineBuffer[0] == ';' || lineBuffer[0] == '#') continue;
 			auto c = lineBuffer.matchFirst(configRegex);
 			if (c.empty) {

src/curlEngine.d

@@ -176,55 +176,62 @@ class CurlResponse {
 
 class CurlEngine {
 
-	__gshared CurlEngine[] curlEnginePool;
+	__gshared static CurlEngine[] curlEnginePool;  // __gshared is used for thread-shared static variables
+    
+    HTTP http;
+    bool keepAlive;
+    ulong dnsTimeout;
+    CurlResponse response;
+    File uploadFile;
 
-	static CurlEngine get() {
-		synchronized(CurlEngine.classinfo) {
-			if (curlEnginePool.empty) {
-				return new CurlEngine;
-			} else {
-				CurlEngine curlEngine = curlEnginePool[$-1];
-				curlEnginePool.popBack();
-				return curlEngine;
-			}
-		}
-	}
+    static CurlEngine getCurlInstance() {
+        synchronized (CurlEngine.classinfo) {
+            if (curlEnginePool.empty) {
+                return new CurlEngine;  // Constructs a new CurlEngine with a fresh HTTP instance
+            } else {
+                CurlEngine curlEngine = curlEnginePool[$ - 1];
+                curlEnginePool = curlEnginePool[0 .. $ - 1];  
+                return curlEngine;
+            }
+        }
+    }
 
-	static releaseAll() {
-		synchronized(CurlEngine.classinfo) {
-			foreach(curlEngine; curlEnginePool) {
-				curlEngine.shutdown();
+    static void releaseAll() {
+		synchronized (CurlEngine.classinfo) {
+            foreach (CurlEngine curlEngine; curlEnginePool) {
+				curlEngine.cleanUp(); // Cleanup instance by resetting values
+                curlEngine.shutdown();  // Assume proper cleanup of any resources used by HTTP
 				object.destroy(curlEngine);
-			}
-			curlEnginePool = null;
-		}
-	}
+            }
+            curlEnginePool.length = 0;
+        }
+		
+		// Cleanup curlEnginePool
+		object.destroy(curlEnginePool);
+    }
 
-	void release() {
-		cleanUp();
-		synchronized(CurlEngine.classinfo) {
-			curlEnginePool ~= this;
-		}
-	}
+    this() {
+        http = HTTP();   // Directly initializes HTTP using its default constructor
+        response = null; // Initialize as null
+    }
 
-	HTTP http;
-	bool keepAlive;
-	ulong dnsTimeout;
-	CurlResponse response;
-	File uploadFile;
-
-	this() {	
-		http = HTTP();
-		response = null;
-	}
-
-	~this() {
-		object.destroy(http);
-		object.destroy(response);
+    ~this() {
+        // The destructor should only clean up resources owned directly by this instance
+        // Avoid modifying or destroying shared/static resources here
 		if (uploadFile.isOpen())
-			uploadFile.close();
-	}
+            uploadFile.close();
+
+		// Cleanup curlEnginePool
+		object.destroy(curlEnginePool);
+    }
 	
+	void release() {
+        cleanUp();
+        synchronized (CurlEngine.classinfo) {
+            curlEnginePool ~= this;
+        }
+    }
+
 	void initialise(ulong dnsTimeout, ulong connectTimeout, ulong dataTimeout, ulong operationTimeout, int maxRedirects, bool httpsDebug, string userAgent, bool httpProtocol, ulong userRateLimit, ulong protocolVersion, bool keepAlive=true) {
 		//   Setting this to false ensures that when we close the curl instance, any open sockets are closed - which we need to do when running 
 		//   multiple threads and API instances at the same time otherwise we run out of local files | sockets pretty quickly

src/log.d

@@ -100,7 +100,8 @@ class LogBuffer {
             // Use dnotify's functionality for GUI notifications, if GUI notifications is enabled
 			version(Notifications) {
 				try {
-					auto n = new Notification("Log Notification", message, "IGNORED");
+					auto n = new Notification("OneDrive Client for Linux", message, "IGNORED");
+					//n.timeout = 5;
 					n.show();
 				} catch (NotificationError e) {
 					sendGUINotification = false;

src/main.d

@@ -1123,12 +1123,6 @@ void performStandardExitProcess(string scopeCaller = null) {
 		object.destroy(oneDriveWebhook);
 	}
 	
-	// Shutdown the sync engine
-	if (syncEngineInstance !is null) {
-		addLogEntry("Shutdown Sync Engine instance", ["debug"]);
-		object.destroy(syncEngineInstance);
-	}
-	
 	// Shutdown the client side filtering objects
 	if (selectiveSync !is null) {
 		addLogEntry("Shutdown Client Side Filtering instance", ["debug"]);
@@ -1151,6 +1145,12 @@ void performStandardExitProcess(string scopeCaller = null) {
 		object.destroy(filesystemMonitor);
 	}
 	
+	// Shutdown the sync engine
+	if (syncEngineInstance !is null) {
+		addLogEntry("Shutdown Sync Engine instance", ["debug"]);
+		object.destroy(syncEngineInstance);
+	}
+	
 	// Shutdown the database
 	if (itemDB !is null) {
 		addLogEntry("Shutdown Database instance", ["debug"]);

src/onedrive.d

@@ -113,13 +113,17 @@ class OneDriveApi {
 		// Subscriptions
 		subscriptionUrl = appConfig.globalGraphEndpoint ~ "/v1.0/subscriptions";
 	}
+	
+	~this() {
+		object.destroy(curlEngine);
+	}
 
 	// Initialise the OneDrive API class
 	bool initialise(bool keepAlive=true) {
 		// Initialise the curl engine
 		this.keepAlive = keepAlive;
 		if (curlEngine is null) {
-			curlEngine = CurlEngine.get();
+			curlEngine = CurlEngine.getCurlInstance();
 			curlEngine.initialise(appConfig.getValueLong("dns_timeout"), appConfig.getValueLong("connect_timeout"), appConfig.getValueLong("data_timeout"), appConfig.getValueLong("operation_timeout"), appConfig.defaultMaxRedirects, appConfig.getValueBool("debug_https"), appConfig.getValueString("user_agent"), appConfig.getValueBool("force_http_11"), appConfig.getValueLong("rate_limit"), appConfig.getValueLong("ip_protocol_version"), keepAlive);
 		}
 

src/sync.d

@@ -298,6 +298,13 @@ class SyncEngine {
 		}
 	}
 	
+	~this() {	
+		processPool = null;
+		addLogEntry("processPool = null");
+		object.destroy(oneDriveApiInstance);
+		addLogEntry("object.destroy(oneDriveApiInstance)");
+	}
+	
 	// Initialise the Sync Engine class
 	bool initialise() {
 
@@ -519,7 +526,7 @@ class SyncEngine {
 		addLogEntry("Perform a Full Scan True-Up: " ~ to!string(appConfig.fullScanTrueUpRequired), ["debug"]);
 		
 		// Fetch the API response of /delta to track changes that were performed online
-		fetchOneDriveDeltaAPIResponse(null, null, null);
+		fetchOneDriveDeltaAPIResponse();
 		// Process any download activities or cleanup actions
 		processDownloadActivities();
 		

src/util.d

@@ -201,42 +201,54 @@ Regex!char wild2regex(const(char)[] pattern) {
     return regex(str, "i");
 }
 
-// Test Internet access to Microsoft OneDrive
+// Test Internet access to Microsoft OneDrive using a simple HTTP HEAD request
 bool testInternetReachability(ApplicationConfig appConfig) {
-    CurlEngine curlEngine;
-    bool result = false;
+    auto http = HTTP();
+    http.url = "https://login.microsoftonline.com";
+    
+    // Configure timeouts based on application configuration
+    http.dnsTimeout = dur!"seconds"(appConfig.getValueLong("dns_timeout"));
+    http.connectTimeout = dur!"seconds"(appConfig.getValueLong("connect_timeout"));
+    http.dataTimeout = dur!"seconds"(appConfig.getValueLong("data_timeout"));
+    http.operationTimeout = dur!"seconds"(appConfig.getValueLong("operation_timeout"));
+
+    // Set IP protocol version
+    http.handle.set(CurlOption.ipresolve, appConfig.getValueLong("ip_protocol_version"));
+
+    // Set HTTP method to HEAD for minimal data transfer
+    http.method = HTTP.Method.head;
+
+    // Execute the request and handle exceptions
     try {
-		// Use preconfigured object with all the correct http values assigned
-		curlEngine = CurlEngine.get();
-		curlEngine.initialise(appConfig.getValueLong("dns_timeout"), appConfig.getValueLong("connect_timeout"), appConfig.getValueLong("data_timeout"), appConfig.getValueLong("operation_timeout"), appConfig.defaultMaxRedirects, appConfig.getValueBool("debug_https"), appConfig.getValueString("user_agent"), appConfig.getValueBool("force_http_11"), appConfig.getValueLong("rate_limit"), appConfig.getValueLong("ip_protocol_version"));
+        addLogEntry("Attempting to contact Microsoft OneDrive Login Service");
+        http.perform();
 
-		// Configure the remaining items required
-		// URL to use
-		// HTTP connection test method
+        // Check response for HTTP status code
+        if (http.statusLine.code >= 200 && http.statusLine.code < 400) {
+            addLogEntry("Successfully reached Microsoft OneDrive Login Service");
+        } else {
+            addLogEntry("Failed to reach Microsoft OneDrive Login Service. HTTP status code: " ~ to!string(http.statusLine.code));
+            throw new Exception("HTTP Request Failed with Status Code: " ~ to!string(http.statusLine.code));
+        }
 
-		curlEngine.connect(HTTP.Method.head, "https://login.microsoftonline.com");
-		addLogEntry("Attempting to contact Microsoft OneDrive Login Service", ["debug"]);
-		curlEngine.http.perform();
-		addLogEntry("Shutting down HTTP engine as successfully reached OneDrive Login Service", ["debug"]);
-		result = true;
+        http.shutdown();
+        return true;
     } catch (SocketException e) {
-        addLogEntry("HTTP Socket Issue", ["debug"]);
-        addLogEntry("Cannot connect to Microsoft OneDrive Login Service - Socket Issue");
+        addLogEntry("Cannot connect to Microsoft OneDrive Service - Socket Issue: " ~ e.msg);
         displayOneDriveErrorMessage(e.msg, getFunctionName!({}));
+        http.shutdown();
+        return false;
     } catch (CurlException e) {
-        addLogEntry("No Network Connection", ["debug"]);
-        addLogEntry("Cannot connect to Microsoft OneDrive Login Service - Network Connection Issue");
+        addLogEntry("Cannot connect to Microsoft OneDrive Service - Network Connection Issue: " ~ e.msg);
         displayOneDriveErrorMessage(e.msg, getFunctionName!({}));
-    } 
-
-	// Shutdown engine
-	curlEngine.http.shutdown();
-	curlEngine.releaseAll();
-	object.destroy(curlEngine);
-	curlEngine = null;
-
-	// Return test result
-    return result;
+        http.shutdown();
+        return false;
+    } catch (Exception e) {
+        addLogEntry("Unexpected error occurred: " ~ e.toString());
+        displayOneDriveErrorMessage(e.toString(), getFunctionName!({}));
+        http.shutdown();
+        return false;
+    }
 }
 
 // Retry Internet access test to Microsoft OneDrive