--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DBCache.hpp	Tue Aug 28 18:58:02 2012 +0200
@@ -0,0 +1,360 @@
+#ifndef DBCACHE_HPP
+#define DBCACHE_HPP
+
+#include <QtSql/QSqlDatabase>
+#include <QtSql/QSqlQuery>
+#include <QtSql/QSqlError>
+#include <QtSql/QSqlRecord>
+
+#include <QtCore/QDebug>
+#include <QtCore/QStringList>
+#include <cassert>
+#include "OrderedPair.hpp"
+
+#include <boost/optional.hpp>
+
+#include "ThreadSafeLookup.hpp"
+#include "UniqueString.hpp"
+
+
+template<typename T>
+struct SQLGenerator
+{
+};
+
+template<>
+struct SQLGenerator<int>
+{
+  static QString fieldName(const QString &prefix = QString())
+  {
+    return QString("%1_Int").arg(prefix);
+  }
+
+  static QString createFields(const QString &prefix = QString())
+  {
+    return QString("%1 INTEGER").arg(fieldName(prefix));
+  }
+
+  static QString valueString(const QString &prefix = QString())
+  {
+    return QString(":") + fieldName(prefix);
+  }
+
+  static void bindValue(QSqlQuery& query, int value, const QString& prefix = QString())
+  {
+    query.bindValue(valueString(prefix), value);
+  }
+
+  static void bindValues(QSqlQuery& query, const QVariantList& values, const QString& prefix = QString())
+  {
+    query.bindValue(valueString(prefix), values);
+  }
+
+  static void bindValues(QSqlQuery& query, const QList<int>& values, const QString& prefix = QString())
+  {
+    QVariantList list;
+    foreach(int value, values) {
+      list << value;
+    }
+    bindValues(query, list, prefix);
+  }
+
+  static boost::optional<int> extract(QSqlQuery& query, const QString& prefix = QString())
+  {
+    int fieldNo = query.record().indexOf(fieldName(prefix));
+    if (query.at() >= 0)
+      return query.value(fieldNo).toInt();
+    else
+      return boost::optional<int>();
+  }
+
+};
+
+template<>
+struct SQLGenerator<QString>
+{
+  static QString fieldName(const QString &prefix = QString())
+  {
+    return QString("%1_QString").arg(prefix);
+  }
+
+  static QString createFields(const QString &prefix = QString())
+  {
+    return QString("%1 TEXT").arg(fieldName(prefix));
+  }
+
+  static QString valueString(const QString &prefix = QString())
+  {
+    return QString(":") + fieldName(prefix);
+  }
+
+  static QString restrict(const QString &prefix = QString())
+  {
+    return QString("%1 = %2").arg(fieldName(prefix)).arg(valueString(prefix));
+  }
+
+  static void bindValue(QSqlQuery& query, const QString& value, const QString& prefix = QString())
+  {
+    query.bindValue(valueString(prefix), value);
+  }
+
+  static void bindValues(QSqlQuery& query, const QVariantList& value, const QString& prefix = QString())
+  {
+    query.bindValue(valueString(prefix), value);
+  }
+
+  static void bindValues(QSqlQuery& query, const QList<QString>& values, const QString& prefix = QString())
+  {
+    QVariantList list;
+    foreach(const QString& value, values) {
+      list << value;
+    }
+    bindValues(query, list, prefix);
+  }
+
+  static boost::optional<QString> extract(QSqlQuery& query, const QString& prefix = QString())
+  {
+    int fieldNo = query.record().indexOf(fieldName(prefix));
+    if (query.at() >= 0)
+      return query.value(fieldNo).toString();
+    else
+      return boost::optional<QString>();
+  }
+
+
+};
+
+template<>
+struct SQLGenerator<UniqueString>
+{
+  static QString fieldName(const QString &prefix = QString())
+  {
+    return QString("%1_QString").arg(prefix);
+  }
+
+  static QString createFields(const QString &prefix = QString())
+  {
+    return QString("%1 TEXT").arg(fieldName(prefix));
+  }
+
+  static QString valueString(const QString &prefix = QString())
+  {
+    return QString(":") + fieldName(prefix);
+  }
+
+  static QString restrict(const QString &prefix = QString())
+  {
+    return QString("%1 = %2").arg(fieldName(prefix)).arg(valueString(prefix));
+  }
+
+  static void bindValue(QSqlQuery& query, const QString& value, const QString& prefix = QString())
+  {
+    query.bindValue(valueString(prefix), value);
+  }
+
+  static void bindValues(QSqlQuery& query, const QVariantList& value, const QString& prefix = QString())
+  {
+    query.bindValue(valueString(prefix), value);
+  }
+
+  static void bindValues(QSqlQuery& query, const QList<UniqueString>& values, const QString& prefix = QString())
+  {
+    QVariantList list;
+    foreach(const QString& value, values) {
+      list << value;
+    }
+    bindValues(query, list, prefix);
+  }
+
+  static boost::optional<QString> extract(QSqlQuery& query, const QString& prefix = QString())
+  {
+    int fieldNo = query.record().indexOf(fieldName(prefix));
+    if (query.at() >= 0)
+      return query.value(fieldNo).toString();
+    else
+      return boost::optional<QString>();
+  }
+
+
+};
+
+template<typename T>
+struct SQLGenerator<OrderedPair<T> >
+{
+  static QString fieldName(const QString &prefix = QString())
+  {
+    return SQLGenerator<T>::fieldName(prefix + "_1") + ", " +
+      SQLGenerator<T>::fieldName(prefix + "_2");
+  }
+
+  static QString createFields(const QString &prefix = QString())
+  {
+    return SQLGenerator<T>::createFields(prefix + "_1") + ", " +
+      SQLGenerator<T>::createFields(prefix + "_2");
+  }
+
+  static QString restriction(const QString& prefix = QString())
+  {
+    return SQLGenerator<T>::restrict(prefix + "_1") + " AND " +
+      SQLGenerator<T>::restrict(prefix + "_2");    
+  }
+
+  static QString valueString(const QString &prefix = QString())
+  {
+    return SQLGenerator<T>::valueString(prefix + "_1") + ", " +
+      SQLGenerator<T>::valueString(prefix + "_2");
+  }
+
+  static void bindValue(QSqlQuery& query, const OrderedPair<T>& value, const QString& prefix = QString())
+  {
+    SQLGenerator<T>::bindValue(query, value.first, prefix + "_1");
+    SQLGenerator<T>::bindValue(query, value.second, prefix + "_2");
+  }
+
+  static void bindValues(QSqlQuery& query, const QList<OrderedPair<T> >& values, const QString& prefix = QString())
+  {
+    QList<T> first;
+    QList<T> second;
+    foreach(OrderedPair<T> value, values) {
+      first << value.first;
+      second << value.second;
+    }
+    SQLGenerator<T>::bindValues(query, first, prefix + "_1");
+    SQLGenerator<T>::bindValues(query, second, prefix + "_2");
+  }
+
+  static boost::optional<OrderedPair<T> > extract(QSqlQuery& query, const QString& prefix = QString())
+  {
+    if (query.at() >= 0)
+      return OrderedPair<T> (*SQLGenerator<T>::extract(query, prefix + "_1"),
+			     *SQLGenerator<T>::extract(query, prefix + "_2"));
+    else
+      return boost::optional<OrderedPair<T> >();
+  }
+
+
+};
+
+template<typename Key, typename Value, bool memoryMapped = false>
+class DBCache
+{
+private:
+  ThreadSafeLookup<Key, Value> memoryMap;
+  QList<Key> unsyncedKeys;
+
+  void setup(const QSqlDatabase& db, const QString& dictName)
+  {
+    this->dictName = dictName;
+    if (!db.tables().contains(dictName)) {
+      QString keyFields = SQLGenerator<Key>::createFields("key");
+      QString valueFields = SQLGenerator<Value>::createFields("value");
+      QString createQuery = QString("CREATE TABLE %1(%2, %3);").arg(dictName).arg(keyFields).arg(valueFields);
+      QSqlQuery query(db);
+      query.exec(createQuery);
+    }
+    if (!db.tables().contains(dictName)) {
+      qDebug()<<"No database";
+      exit(1);
+    }
+    if (memoryMapped) {
+      QString keyFields = SQLGenerator<Key>::fieldName("key");
+      QString valueFields = SQLGenerator<Value>::fieldName("value");
+      QString repopulateQuery = QString("SELECT %1, %2 FROM %3;").arg(keyFields).arg(valueFields).arg(dictName);
+      QSqlQuery query(db);
+      if (!query.exec(repopulateQuery)) {
+	qDebug() << query.lastError() << repopulateQuery;
+      }
+      while (query.next()) {
+	Key key = *SQLGenerator<Key>::extract(query, "key");
+	Value value = *SQLGenerator<Value>::extract(query, "value");
+	memoryMap.insert(key, value);
+      }
+    }
+    QString queryString = QString("INSERT into %1 (%2, %3) VALUES(%4, %5);")
+      .arg(dictName)
+      .arg(SQLGenerator<Key>::fieldName("key"))
+      .arg(SQLGenerator<Value>::fieldName("value"))
+      .arg(SQLGenerator<Key>::valueString("key"))
+      .arg(SQLGenerator<Value>::valueString("value"));
+    insertQuery = QSqlQuery(db);
+    insertQuery.prepare(queryString);
+  }
+
+  void syncInsert()
+  {
+    SQLGenerator<Key>::bindValues(insertQuery, unsyncedKeys, "key");
+    QList<Value> values;
+    foreach(Key key, unsyncedKeys) {
+      values << *memoryMap.value(key);
+    }
+    SQLGenerator<Value>::bindValues(insertQuery, values, "value");
+    if (!insertQuery.exec()) {
+      qDebug() << insertQuery.lastError() << insertQuery.lastQuery();
+    }
+    insertQuery.finish();
+    unsyncedKeys.clear();
+  }
+
+public:
+  DBCache(const QString& dbName, const QString& dictName) 
+  {
+    db = QSqlDatabase::addDatabase("QSQLITE", "dictName");
+    db.setDatabaseName(dbName);
+    bool ok = db.open();
+    assert(ok);
+    setup(db, dictName);
+  }
+
+  DBCache(const QSqlDatabase& db, const QString& dictName) 
+  {
+    setup(db, dictName);
+  }
+
+  boost::optional<Value> value(const Key& key) const
+  {
+    if (memoryMapped) {
+      return memoryMap.value(key);
+    }
+    else {
+      QString queryString = QString("SELECT %1 FROM %2 WHERE %3")
+	.arg(SQLGenerator<Value>::fieldName("value"))
+	.arg(dictName)
+	.arg(SQLGenerator<Key>::restriction("key"));
+      QSqlQuery query(db);
+      query.prepare(queryString);
+      SQLGenerator<Key>::bindValue(query, key, "key");
+      if (!query.exec()) {
+	qDebug() << query.lastError() << queryString;
+      }
+      query.next();
+      return SQLGenerator<Value>::extract(query, "value");
+    }
+  }
+
+  void insert(const Key& key, const Value& value)
+  {
+    if (memoryMapped) {
+      memoryMap.insert(key, value);
+      unsyncedKeys.append(key);
+      if (unsyncedKeys.size() > 1024) {
+	syncInsert();
+      }
+    }
+    else {
+      SQLGenerator<Key>::bindValue(insertQuery, key, "key");
+      SQLGenerator<Value>::bindValue(insertQuery, value, "value");
+      if (!insertQuery.exec()) {
+	qDebug() << insertQuery.lastError() << insertQuery.lastQuery();
+      }
+      insertQuery.finish();
+    }
+      
+  }
+
+private:
+  QSqlDatabase db;
+  QString dictName;
+  QSqlQuery insertQuery;
+};
+
+#endif //DBCACHE_HPP