refactor: add instance creation abstraction and move vanilla

This is so that 1. Code is more cleanly separated, and 2. Allows to more
easily add instance updating :)

Signed-off-by: flow <flowlnlnln@gmail.com>

6 files changed, 99 insertions, 54 deletions

diff --git a/launcher/CMakeLists.txt b/launcher/CMakeLists.txt
index 848d2e51..c51cd6bd 100644
--- a/launcher/CMakeLists.txt
+++ b/launcher/CMakeLists.txt
@@ -297,6 +297,8 @@ set(MINECRAFT_SOURCES
     minecraft/Library.cpp
     minecraft/Library.h
     minecraft/MojangDownloadInfo.h
+    minecraft/VanillaInstanceCreationTask.cpp
+    minecraft/VanillaInstanceCreationTask.h
     minecraft/VersionFile.cpp
     minecraft/VersionFile.h
     minecraft/VersionFilterData.h
diff --git a/launcher/InstanceCreationTask.cpp b/launcher/InstanceCreationTask.cpp
index e01bf306..c8c91997 100644
--- a/launcher/InstanceCreationTask.cpp
+++ b/launcher/InstanceCreationTask.cpp
@@ -1,40 +1,18 @@
 #include "InstanceCreationTask.h"
-#include "settings/INISettingsObject.h"
-#include "FileSystem.h"
 
-//FIXME: remove this
-#include "minecraft/MinecraftInstance.h"
-#include "minecraft/PackProfile.h"
+#include <QDebug>
 
-InstanceCreationTask::InstanceCreationTask(BaseVersionPtr version)
-{
-    m_version = version;
-    m_usingLoader = false;
-}
-
-InstanceCreationTask::InstanceCreationTask(BaseVersionPtr version, QString loader, BaseVersionPtr loaderVersion)
-{
-    m_version = version;
-    m_usingLoader = true;
-    m_loader = loader;
-    m_loaderVersion = loaderVersion;
-}
+InstanceCreationTask::InstanceCreationTask() {}
 
 void InstanceCreationTask::executeTask()
 {
-    setStatus(tr("Creating instance from version %1").arg(m_version->name()));
-    {
-        auto instanceSettings = std::make_shared<INISettingsObject>(FS::PathCombine(m_stagingPath, "instance.cfg"));
-        instanceSettings->suspendSave();
-        MinecraftInstance inst(m_globalSettings, instanceSettings, m_stagingPath);
-        auto components = inst.getPackProfile();
-        components->buildingFromScratch();
-        components->setComponentVersion("net.minecraft", m_version->descriptor(), true);
-        if(m_usingLoader)
-            components->setComponentVersion(m_loader, m_loaderVersion->descriptor());
-        inst.setName(m_instName);
-        inst.setIconKey(m_instIcon);
-        instanceSettings->resumeSave();
+    if (updateInstance() || createInstance()) {
+        emitSucceeded();
+        return;
     }
-    emitSucceeded();
+
+    qWarning() << "Instance creation failed!";
+    if (!m_error_message.isEmpty())
+        qWarning() << "Reason: " << m_error_message;
+    emitFailed(tr("Error while creating new instance."));
 }
diff --git a/launcher/InstanceCreationTask.h b/launcher/InstanceCreationTask.h
index 23367c3f..af854713 100644
--- a/launcher/InstanceCreationTask.h
+++ b/launcher/InstanceCreationTask.h
@@ -1,26 +1,39 @@
 #pragma once
 
-#include "tasks/Task.h"
-#include "net/NetJob.h"
-#include <QUrl>
-#include "settings/SettingsObject.h"
 #include "BaseVersion.h"
 #include "InstanceTask.h"
 
-class InstanceCreationTask : public InstanceTask
-{
+class InstanceCreationTask : public InstanceTask {
     Q_OBJECT
-public:
-    explicit InstanceCreationTask(BaseVersionPtr version);
-    explicit InstanceCreationTask(BaseVersionPtr version, QString loader, BaseVersionPtr loaderVersion);
+   public:
+    InstanceCreationTask();
+    virtual ~InstanceCreationTask() = default;
 
-protected:
-    //! Entry point for tasks.
-    virtual void executeTask() override;
+   protected:
+    void executeTask() final override;
 
-private: /* data */
-    BaseVersionPtr m_version;
-    bool m_usingLoader;
-    QString m_loader;
-    BaseVersionPtr m_loaderVersion;
+    /**
+     * Tries to update an already existing instance.
+     *
+     * This can be implemented by subclasses to provide a way of updating an already existing
+     * instance, according to that implementation's concept of 'identity' (i.e. instances that
+     * are updates / downgrades of one another).
+     *
+     * If this returns true, createInstance() will not run, so you should do all update steps in here.
+     * Otherwise, createInstance() is run as normal.
+     */
+    virtual bool updateInstance() { return false; };
+
+    /**
+     * Creates a new instance.
+     *
+     * Returns whether the instance creation was successful (true) or not (false).
+     */
+    virtual bool createInstance() { return false; };
+
+   protected:
+    void setError(QString message) { m_error_message = message; };
+
+   private:
+    QString m_error_message;
 };
diff --git a/launcher/minecraft/VanillaInstanceCreationTask.cpp b/launcher/minecraft/VanillaInstanceCreationTask.cpp
new file mode 100644
index 00000000..2d1593b6
--- /dev/null
+++ b/launcher/minecraft/VanillaInstanceCreationTask.cpp
@@ -0,0 +1,32 @@
+#include "VanillaInstanceCreationTask.h"
+
+#include "FileSystem.h"
+#include "settings/INISettingsObject.h"
+#include "minecraft/MinecraftInstance.h"
+#include "minecraft/PackProfile.h"
+
+VanillaCreationTask::VanillaCreationTask(BaseVersionPtr version, QString loader, BaseVersionPtr loader_version)
+    : InstanceCreationTask(), m_version(version), m_using_loader(true), m_loader(loader), m_loader_version(loader_version)
+{}
+
+bool VanillaCreationTask::createInstance()
+{
+    setStatus(tr("Creating instance from version %1").arg(m_version->name()));
+
+    auto instance_settings = std::make_shared<INISettingsObject>(FS::PathCombine(m_stagingPath, "instance.cfg"));
+    instance_settings->suspendSave();
+    {
+        MinecraftInstance inst(m_globalSettings, instance_settings, m_stagingPath);
+        auto components = inst.getPackProfile();
+        components->buildingFromScratch();
+        components->setComponentVersion("net.minecraft", m_version->descriptor(), true);
+        if(m_using_loader)
+            components->setComponentVersion(m_loader, m_loader_version->descriptor());
+
+        inst.setName(m_instName);
+        inst.setIconKey(m_instIcon);
+    }
+    instance_settings->resumeSave();
+
+    return true;
+}
diff --git a/launcher/minecraft/VanillaInstanceCreationTask.h b/launcher/minecraft/VanillaInstanceCreationTask.h
new file mode 100644
index 00000000..540ecb70
--- /dev/null
+++ b/launcher/minecraft/VanillaInstanceCreationTask.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include "InstanceCreationTask.h"
+
+class VanillaCreationTask final : public InstanceCreationTask {
+    Q_OBJECT
+   public:
+    VanillaCreationTask(BaseVersionPtr version) : InstanceCreationTask(), m_version(version) {}
+    VanillaCreationTask(BaseVersionPtr version, QString loader, BaseVersionPtr loader_version);
+
+    bool createInstance() override;
+
+   private:
+    // Version to update to / create of the instance.
+    BaseVersionPtr m_version;
+
+    bool m_using_loader = false;
+    QString m_loader;
+    BaseVersionPtr m_loader_version;
+};
diff --git a/launcher/ui/pages/modplatform/VanillaPage.cpp b/launcher/ui/pages/modplatform/VanillaPage.cpp
index a026947f..99190f31 100644
--- a/launcher/ui/pages/modplatform/VanillaPage.cpp
+++ b/launcher/ui/pages/modplatform/VanillaPage.cpp
@@ -39,12 +39,12 @@
 #include <QTabBar>
 
 #include "Application.h"
+#include "Filter.h"
+#include "Version.h"
 #include "meta/Index.h"
 #include "meta/VersionList.h"
+#include "minecraft/VanillaInstanceCreationTask.h"
 #include "ui/dialogs/NewInstanceDialog.h"
-#include "Filter.h"
-#include "InstanceCreationTask.h"
-#include "Version.h"
 
 VanillaPage::VanillaPage(NewInstanceDialog *dialog, QWidget *parent)
     : QWidget(parent), dialog(dialog), ui(new Ui::VanillaPage)
@@ -217,11 +217,11 @@ void VanillaPage::suggestCurrent()
 
     // There isn't a selected version if the version list is empty
     if(ui->loaderVersionList->selectedVersion() == nullptr)
-        dialog->setSuggestedPack(m_selectedVersion->descriptor(), new InstanceCreationTask(m_selectedVersion));
+        dialog->setSuggestedPack(m_selectedVersion->descriptor(), new VanillaCreationTask(m_selectedVersion));
     else
     {
         dialog->setSuggestedPack(m_selectedVersion->descriptor(),
-                                 new InstanceCreationTask(m_selectedVersion, m_selectedLoader,
+                                 new VanillaCreationTask(m_selectedVersion, m_selectedLoader,
                                                           m_selectedLoaderVersion));
     }
     dialog->setSuggestedIcon("default");