1 files changed, 168 insertions, 0 deletions
diff --git a/launcher/meta/BaseEntity.cpp b/launcher/meta/BaseEntity.cpp
new file mode 100644
index 00000000..5ff7a59a
--- /dev/null
+++ b/launcher/meta/BaseEntity.cpp
@@ -0,0 +1,168 @@
+/* Copyright 2015-2021 MultiMC Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "BaseEntity.h"
+
+#include "Json.h"
+
+#include "net/Download.h"
+#include "net/HttpMetaCache.h"
+#include "net/NetJob.h"
+
+#include "Env.h"
+#include "Json.h"
+
+#include "BuildConfig.h"
+
+class ParsingValidator : public Net::Validator
+{
+public: /* con/des */
+    ParsingValidator(Meta::BaseEntity *entity) : m_entity(entity)
+    {
+    };
+    virtual ~ParsingValidator()
+    {
+    };
+
+public: /* methods */
+    bool init(QNetworkRequest &) override
+    {
+        return true;
+    }
+    bool write(QByteArray & data) override
+    {
+        this->data.append(data);
+        return true;
+    }
+    bool abort() override
+    {
+        return true;
+    }
+    bool validate(QNetworkReply &) override
+    {
+        auto fname = m_entity->localFilename();
+        try
+        {
+            auto doc = Json::requireDocument(data, fname);
+            auto obj = Json::requireObject(doc, fname);
+            m_entity->parse(obj);
+            return true;
+        }
+        catch (const Exception &e)
+        {
+            qWarning() << "Unable to parse response:" << e.cause();
+            return false;
+        }
+    }
+
+private: /* data */
+    QByteArray data;
+    Meta::BaseEntity *m_entity;
+};
+
+Meta::BaseEntity::~BaseEntity()
+{
+}
+
+QUrl Meta::BaseEntity::url() const
+{
+    return QUrl(BuildConfig.META_URL).resolved(localFilename());
+}
+
+bool Meta::BaseEntity::loadLocalFile()
+{
+    const QString fname = QDir("meta").absoluteFilePath(localFilename());
+    if (!QFile::exists(fname))
+    {
+        return false;
+    }
+    // TODO: check if the file has the expected checksum
+    try
+    {
+        auto doc = Json::requireDocument(fname, fname);
+        auto obj = Json::requireObject(doc, fname);
+        parse(obj);
+        return true;
+    }
+    catch (const Exception &e)
+    {
+        qDebug() << QString("Unable to parse file %1: %2").arg(fname, e.cause());
+        // just make sure it's gone and we never consider it again.
+        QFile::remove(fname);
+        return false;
+    }
+}
+
+void Meta::BaseEntity::load(Net::Mode loadType)
+{
+    // load local file if nothing is loaded yet
+    if(!isLoaded())
+    {
+        if(loadLocalFile())
+        {
+            m_loadStatus = LoadStatus::Local;
+        }
+    }
+    // if we need remote update, run the update task
+    if(loadType == Net::Mode::Offline || !shouldStartRemoteUpdate())
+    {
+        return;
+    }
+    NetJob *job = new NetJob(QObject::tr("Download of meta file %1").arg(localFilename()));
+    auto url = this->url();
+    auto entry = ENV.metacache()->resolveEntry("meta", localFilename());
+    entry->setStale(true);
+    auto dl = Net::Download::makeCached(url, entry);
+    /*
+     * The validator parses the file and loads it into the object.
+     * If that fails, the file is not written to storage.
+     */
+    dl->addValidator(new ParsingValidator(this));
+    job->addNetAction(dl);
+    m_updateStatus = UpdateStatus::InProgress;
+    m_updateTask.reset(job);
+    QObject::connect(job, &NetJob::succeeded, [&]()
+    {
+        m_loadStatus = LoadStatus::Remote;
+        m_updateStatus = UpdateStatus::Succeeded;
+        m_updateTask.reset();
+    });
+    QObject::connect(job, &NetJob::failed, [&]()
+    {
+        m_updateStatus = UpdateStatus::Failed;
+        m_updateTask.reset();
+    });
+    m_updateTask->start();
+}
+
+bool Meta::BaseEntity::isLoaded() const
+{
+    return m_loadStatus > LoadStatus::NotLoaded;
+}
+
+bool Meta::BaseEntity::shouldStartRemoteUpdate() const
+{
+    // TODO: version-locks and offline mode?
+    return m_updateStatus != UpdateStatus::InProgress;
+}
+
+shared_qobject_ptr<Task> Meta::BaseEntity::getCurrentTask()
+{
+    if(m_updateStatus == UpdateStatus::InProgress)
+    {
+        return m_updateTask;
+    }
+    return nullptr;
+}