Rework the database system

src/CMakeLists.txt

@@ -5,6 +5,7 @@ set(alligator_SRCS
     fetcher.cpp
     feed.cpp
     entry.cpp
+    database.cpp
     resources.qrc
     )
 

src/database.cpp

@@ -0,0 +1,89 @@
+/**
+ * Copyright 2020 Tobias Fella <fella@posteo.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License or (at your option) version 3 or any later version
+ * accepted by the membership of KDE e.V. (or its successor approved
+ * by the membership of KDE e.V.), which shall act as a proxy
+ * defined in Section 14 of version 3 of the license.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <QDir>
+#include <QStandardPaths>
+#include <QSqlError>
+#include <QSqlDatabase>
+
+#include "database.h"
+#include "alligator-debug.h"
+
+#define TRUE_OR_RETURN(x) if(!x) return false;
+
+Database::Database()
+{
+    QSqlDatabase db = QSqlDatabase::addDatabase(QStringLiteral("QSQLITE"));
+    QString databasePath = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
+    QDir(databasePath).mkpath(databasePath);
+    db.setDatabaseName(databasePath + QStringLiteral("/database.db3"));
+    qCDebug(ALLIGATOR) << "Opening database " << databasePath << "/database.db3";
+    db.open();
+
+    if(!migrate()) {
+        qCCritical(ALLIGATOR) << "Failed to migrate the database";
+    }
+}
+
+bool Database::migrate() {
+    qCDebug(ALLIGATOR) << "Migrating database";
+    if(version() < 1) TRUE_OR_RETURN(migrateTo1());
+    return true;
+}
+
+bool Database::migrateTo1() {
+    QSqlQuery query(QSqlDatabase::database());
+    TRUE_OR_RETURN(execute(QStringLiteral("CREATE TABLE IF NOT EXISTS Feeds (name TEXT, url TEXT);")));
+    TRUE_OR_RETURN(execute(QStringLiteral("CREATE TABLE IF NOT EXISTS Entries (feed TEXT, id TEXT, title TEXT, content TEXT);")));
+    TRUE_OR_RETURN(execute(QStringLiteral("CREATE TABLE IF NOT EXISTS Authors (id TEXT, name TEXT, uri TEXT, email TEXT);")));
+    TRUE_OR_RETURN(execute(QStringLiteral("PRAGMA user_version = 1;")));
+    return true;
+}
+
+bool Database::execute(QString query) {
+    QSqlQuery q;
+    q.prepare(query);
+    return execute(q);
+}
+
+bool Database::execute(QSqlQuery &query) {
+    if(!query.exec()) {
+        qCWarning(ALLIGATOR) << "Failed to execute SQL Query";
+        qCWarning(ALLIGATOR) << query.lastQuery();
+        qCWarning(ALLIGATOR) << query.lastError();
+        return false;
+    }
+    return true;
+}
+
+int Database::version() {
+    QSqlQuery query;
+    query.prepare(QStringLiteral("PRAGMA user_version;"));
+    execute(query);
+    if(query.next()) {
+        bool ok;
+        int value = query.value(0).toInt(&ok);
+        qCDebug(ALLIGATOR) << "Database version " << value;
+        if(ok) return value;
+    } else {
+        qCCritical(ALLIGATOR) << "Failed to check database version";
+    }
+    return -1;
+}

src/database.h

@@ -0,0 +1,42 @@
+/**
+ * Copyright 2020 Tobias Fella <fella@posteo.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License or (at your option) version 3 or any later version
+ * accepted by the membership of KDE e.V. (or its successor approved
+ * by the membership of KDE e.V.), which shall act as a proxy
+ * defined in Section 14 of version 3 of the license.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QSqlQuery>
+
+class Database
+{
+public:
+    static Database &instance()
+    {
+        static Database _instance;
+        return _instance;
+    }
+    bool execute(QSqlQuery &query);
+    bool execute(QString query);
+
+private:
+    Database();
+    int version();
+
+    bool migrate();
+    bool migrateTo1();
+};

src/entryListModel.cpp

@@ -18,12 +18,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <QSqlDatabase>
-#include <QSqlQuery>
 #include <QVector>
 
 #include "entryListModel.h"
 #include "fetcher.h"
+#include "database.h"
 
 EntryListModel::EntryListModel(QObject *parent)
     : QAbstractListModel(parent)
@@ -70,10 +69,10 @@ void EntryListModel::fetch()
 {
     connect(&Fetcher::instance(), &Fetcher::finished, this, [this]() {
         beginResetModel();
-        QSqlQuery query(QSqlDatabase::database());
+        QSqlQuery query;
         query.prepare(QStringLiteral("SELECT id, title, content FROM Entries WHERE feed=:feed;"));
         query.bindValue(QStringLiteral(":feed"), m_feed);
-        query.exec();
+        Database::instance().execute(query);
         while (query.next()) {
             m_entries.append(Entry(query.value(1).toString(), query.value(2).toString(), false, false));
         }

src/feedListModel.cpp

@@ -18,21 +18,22 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <QSqlDatabase>
-#include <QSqlQuery>
 #include <QUrl>
-#include <QSqlError>
 
 #include <Syndication/Syndication>
 
 #include "feedListModel.h"
 #include "fetcher.h"
+#include "database.h"
+
+#include "alligator-debug.h"
 
 FeedListModel::FeedListModel(QObject *parent)
     : QAbstractListModel(parent)
 {
-    QSqlQuery query(QSqlDatabase::database());
-    query.exec(QStringLiteral("SELECT name, url FROM Feeds"));
+    QSqlQuery query;
+    query.prepare(QStringLiteral("SELECT name, url FROM Feeds"));
+    Database::instance().execute(query);
     beginInsertRows(QModelIndex(), 0, query.size());
     while (query.next()) {
         feeds += Feed(query.value(1).toString(), query.value(0).toString());
@@ -63,11 +64,17 @@ int FeedListModel::rowCount(const QModelIndex &index) const
 
 void FeedListModel::addFeed(QString url)
 {
+    QSqlQuery query;
+    query.prepare(QStringLiteral("SELECT COUNT (url) FROM Feeds WHERE url=:url;"));
+    query.bindValue(QStringLiteral(":url"), url);
+    Database::instance().execute(query);
+    query.next();
+    if(query.value(0).toInt() != 0) return;
     connect(&Fetcher::instance(), &Fetcher::finished, this, [this, url]() {
-        QSqlQuery query(QSqlDatabase::database());
+        QSqlQuery query;
         query.prepare(QStringLiteral("SELECT name FROM Feeds WHERE url=:url;"));
         query.bindValue(QStringLiteral(":url"), url);
-        query.exec();
+        Database::instance().execute(query);
         query.next();
         for(int i = 0; i < feeds.length(); i++) {
             if(feeds[i].url() == url) {
@@ -82,21 +89,21 @@ void FeedListModel::addFeed(QString url)
     beginInsertRows(QModelIndex(), feeds.size(), feeds.size());
     feeds.append(Feed(url));
     endInsertRows();
-    QSqlQuery query(QSqlDatabase::database());
+
     query.prepare(QStringLiteral("INSERT INTO Feeds VALUES (:url, :name);"));
     query.bindValue(QStringLiteral(":url"), url);
     query.bindValue(QStringLiteral(":name"), url);
-    query.exec();
+    Database::instance().execute(query);
 }
 
 void FeedListModel::remove_feed(int index)
 {
     Feed toRemove = feeds[index];
-    QSqlQuery query(QSqlDatabase::database());
+    QSqlQuery query;
     query.prepare(QStringLiteral("DELETE FROM Feeds WHERE name=:name AND url=url;"));
     query.bindValue(QStringLiteral(":url"), toRemove.url());
     query.bindValue(QStringLiteral(":name"), toRemove.name());
-    query.exec();
+    Database::instance().execute(query);
     beginRemoveRows(QModelIndex(), index, index);
     feeds.remove(index);
     endRemoveRows();

src/fetcher.cpp

@@ -20,13 +20,13 @@
 
 #include <QNetworkAccessManager>
 #include <QNetworkReply>
-#include <QSqlDatabase>
-#include <QSqlQuery>
 
 #include <Syndication/Syndication>
 
 #include "fetcher.h"
 
+#include "database.h"
+
 Fetcher::Fetcher() {
 }
 
@@ -47,7 +47,6 @@ void Fetcher::fetch(QUrl url)
         QSqlQuery query(db);
 
         for (const auto &entry : feed->items()) {
-            query = QSqlQuery(db);
             query.prepare(QStringLiteral("INSERT INTO Entries VALUES (:feed, :id, :title, :content);"));
             query.bindValue(QStringLiteral(":feed"), url.toString());
             query.bindValue(QStringLiteral(":id"), entry->id());
@@ -56,7 +55,7 @@ void Fetcher::fetch(QUrl url)
                 query.bindValue(QStringLiteral(":content"), entry->content());
             else
                 query.bindValue(QStringLiteral(":content"), entry->description());
-            query.exec();
+            Database::instance().execute(query);
             for (const auto &author : entry->authors()) {
                 query = QSqlQuery(db);
                 query.prepare(QStringLiteral("INSERT INTO Authors VALUES(:id, :name, :uri, :email);"));
@@ -64,12 +63,12 @@ void Fetcher::fetch(QUrl url)
                 query.bindValue(QStringLiteral(":name"), author->name());
                 query.bindValue(QStringLiteral(":uri"), author->uri());
                 query.bindValue(QStringLiteral(":email"), author->email());
-                query.exec();
+                Database::instance().execute(query);
             }
             query.prepare(QStringLiteral("UPDATE Feeds SET name=:name WHERE url=:url;"));
             query.bindValue(QStringLiteral(":name"), feed->title());
             query.bindValue(QStringLiteral(":url"), url.toString());
-            query.exec();
+            Database::instance().execute(query);
         }
         delete reply;
         emit finished();

src/main.cpp

@@ -21,14 +21,10 @@
 #include <QApplication>
 #include <QQmlApplicationEngine>
 #include <QQuickView>
-#include <QSqlDatabase>
-#include <QSqlQuery>
-#include <QUrl>
-#include <QStandardPaths>
-#include <QDir>
 
 #include "entryListModel.h"
 #include "feedListModel.h"
+#include "database.h"
 
 #include "alligator-debug.h"
 
@@ -48,16 +44,7 @@ Q_DECL_EXPORT int main(int argc, char *argv[])
 
     QQmlApplicationEngine engine;
 
-    QSqlDatabase db = QSqlDatabase::addDatabase(QStringLiteral("QSQLITE"));
-    QString databasePath = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
-    QDir(databasePath).mkpath(databasePath);
-    db.setDatabaseName(databasePath + "/database.db3");
-    db.open();
-
-    QSqlQuery query(db);
-    query.exec(QStringLiteral("CREATE TABLE IF NOT EXISTS Feeds (name TEXT, url TEXT);"));
-    query.exec(QStringLiteral("CREATE TABLE IF NOT EXISTS Entries (feed TEXT, id TEXT UNIQUE, title TEXT, content TEXT);"));
-    query.exec(QStringLiteral("CREATE TABLE IF NOT EXISTS Authors (id TEXT, name TEXT, uri TEXT, email TEXT);"));
+    Database::instance();
 
     engine.load(QUrl(QStringLiteral("qrc:///main.qml")));