Various task related improvements.

* Errors are reported back to task users via Failure signals.
* Lwjgl doesn't download on each legacy instance start anymore.
* Tasks were unified when it comes to success/failure.
* Task dialogs don't get spawned after short tasks finish anymore.

backend/tasks/LoginTask.cpp

@@ -71,44 +71,41 @@ void LoginTask::processNetReply(QNetworkReply *reply)
 					QString username = strings[2];
 					QString sessionID = strings[3];
 					
-					LoginResponse response{username, sessionID, latestVersion};
-					emit loginComplete(response);
+					result = {username, sessionID, latestVersion};
+					emitSucceeded();
 				}
 				else
 				{
-					emit loginFailed("Failed to parse Minecraft version string.");
+					emitFailed("Failed to parse Minecraft version string.");
 				}
 			}
 			else
 			{
 				if (responseStr.toLower() == "bad login")
-					emit loginFailed("Invalid username or password.");
+					emitFailed("Invalid username or password.");
 				else if (responseStr.toLower() == "old version")
-					emit loginFailed("Launcher outdated, please update.");
+					emitFailed("Launcher outdated, please update.");
 				else
-					emit loginFailed("Login failed: " + responseStr);
+					emitFailed("Login failed: " + responseStr);
 			}
 		}
 		else if (responseCode == 503)
 		{
-			emit loginFailed("The login servers are currently unavailable. "
-							 "Check http://help.mojang.com/ for more info.");
+			emitFailed("The login servers are currently unavailable. Check http://help.mojang.com/ for more info.");
 		}
 		else
 		{
-			emit loginFailed(QString("Login failed: Unknown HTTP error %1 occurred.").
-							 arg(QString::number(responseCode)));
+			emitFailed(QString("Login failed: Unknown HTTP error %1 occurred.").arg(QString::number(responseCode)));
 		}
 		break;
 	}
 		
 	case QNetworkReply::OperationCanceledError:
-		emit loginFailed("Login canceled.");
+		emitFailed("Login canceled.");
 		break;
 		
 	default:
-		emit loginFailed("Login failed: " + reply->errorString());
+		emitFailed("Login failed: " + reply->errorString());
 		break;
 	}
-	emitEnded();
 }

backend/tasks/LoginTask.h

@@ -40,17 +40,18 @@ class LIBMULTIMC_EXPORT LoginTask : public Task
 	Q_OBJECT
 public:
 	explicit LoginTask(const UserInfo& uInfo, QObject *parent = 0);
+	LoginResponse getResult()
+	{
+		return result;
+	};
 	
-public slots:
+protected slots:
 	void processNetReply(QNetworkReply* reply);
 	
-signals:
-	void loginComplete(LoginResponse loginResponse);
-	void loginFailed(const QString& errorMsg);
-	
 protected:
 	void executeTask();
 	
+	LoginResponse result;
 	QNetworkReply* netReply;
 	UserInfo uInfo;
 };

backend/tasks/Task.cpp

@@ -37,11 +37,6 @@ int Task::getProgress() const
 	return progress;
 }
 
-void Task::calcProgress(int parts, int whole)
-{
-	setProgress((int)((((float)parts) / ((float)whole))*100)); // Not sure if C++ or LISP...
-}
-
 void Task::setProgress(int progress)
 {
 	this->progress = progress;
@@ -58,16 +53,21 @@ void Task::emitStarted()
 {
 	running = true;
 	emit started();
-	emit started(this);
 }
 
-void Task::emitEnded()
+void Task::emitFailed(QString reason)
 {
 	running = false;
-	emit ended();
-	emit ended(this);
+	emit failed(reason);
 }
 
+void Task::emitSucceeded()
+{
+	running = false;
+	emit succeeded();
+}
+
+
 bool Task::isRunning() const
 {
 	return running;

backend/tasks/Task.h

@@ -27,33 +27,21 @@ class LIBMULTIMC_EXPORT Task : public QObject
 public:
 	explicit Task(QObject *parent = 0);
 	
-	// Starts the task.
-	void startTask();
-	
 	QString getStatus() const;
 	int getProgress() const;
-	
 	bool isRunning() const;
 	
-	/*!
-	 * \brief Calculates and sets the task's progress based on the number of parts completed out of the total number to complete.
-	 * This is essentially just shorthand for setProgress((parts / whole) * 100);
-	 * \param parts The parts out of the whole completed. This parameter should
-	 * be less than whole. If it is greater than whole, progress is set to 100.
-	 * \param whole The total number of things that need to be completed.
-	 */
-	void calcProgress(int parts, int whole);
+public slots:
+	void startTask();
 	
 protected slots:
 	void setStatus(const QString& status);
 	void setProgress(int progress);
 	
 signals:
-	void started(Task* task);
-	void ended(Task* task);
-	
 	void started();
-	void ended();
+	void failed(QString reason);
+	void succeeded();
 	
 	void statusChanged(Task* task, const QString& status);
 	void progressChanged(Task* task, int progress);
@@ -65,7 +53,8 @@ protected:
 	virtual void executeTask() = 0;
 	
 	virtual void emitStarted();
-	virtual void emitEnded();
+	virtual void emitFailed(QString reason);
+	virtual void emitSucceeded();
 	
 	virtual void emitStatusChange(const QString &status);
 	virtual void emitProgressChange(int progress);