some thoughts about exceptions

CMakeLists.txt

@@ -25,6 +25,7 @@ endif ()
 add_executable(storage
     main.cpp
     exception.cpp
+    exceptions.cpp
     table.cpp
     database.cpp
 )

database.cpp

@@ -89,10 +89,11 @@ QString Core::DataBase::getName() const
 
 template <class K, class V>
 Core::DataBase::Table<K, V>* Core::DataBase::addTable(const QString& p_name) {
+    std::string nm = p_name.toStdString();
     if (opened) {
-        throw Core::DataBase::Opened(name);
+        throw Core::DataBase::Opened(name, nm);
     }
-    Core::DataBase::Table<K, V>* table = new Core::DataBase::Table<K, V>();
+    Core::DataBase::Table<K, V>* table = new Core::DataBase::Table<K, V>(nm, this);
-    tables.insert(std::make_pair(p_name.toStdString(), table));
+    tables.insert(std::make_pair(nm, table));
     return table;
 }

database.h

@@ -50,9 +50,7 @@ public:
     class Closed;
     class Opened;
     class NotFound;
-    class Empty;
     class Exist;
-    class NoAvatar;
     class Unknown;
 
 private:

exceptions.cpp

@@ -0,0 +1,105 @@
+// Squawk messenger.
+// Copyright (C) 2019  Yury Gubich <blue@macaw.me>
+//
+// 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 3 of the License, or
+// (at your option) any later version.
+//
+// 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 <http://www.gnu.org/licenses/>.
+
+#include "exceptions.h"
+
+Core::DataBase::Directory::Directory(const std::string& p_path):
+    Exception(),
+    path(p_path) {}
+
+std::string Core::DataBase::Directory::getMessage() const {
+    return "Can't create directory for database at " + path;}
+
+Core::DataBase::Closed::Closed(
+    const std::string& p_operation,
+    const std::string& p_dbName,
+    const std::string& p_tableName
+):
+    Exception(),
+    operation(p_operation),
+    dbName(p_dbName),
+    tableName(p_tableName) {}
+
+std::string Core::DataBase::Closed::getMessage() const {
+    return "An attempt to perform operation " + operation
+            + " on closed database " + dbName
+            + " on table " + tableName;
+}
+
+Core::DataBase::Opened::Opened(const std::string& p_dbName, const std::string& p_tableName):
+    Exception(),
+    dbName(p_dbName),
+    tableName(p_tableName) {}
+
+
+std::string Core::DataBase::Opened::getMessage() const {
+    return "An attempt to add table " + tableName
+            + " to the database " + dbName
+            + " but it's can't be done because the DataBase is already opened."
+            + " Please add all tables before opening DataBase.";
+}
+
+Core::DataBase::NotFound::NotFound(
+    const std::string& p_key,
+    const std::string& p_dbName,
+    const std::string& p_tableName
+):
+    Exception(),
+    key(p_key),
+    dbName(p_dbName),
+    tableName(p_tableName) {}
+
+std::string Core::DataBase::NotFound::getMessage() const {
+    return "Element for id " + key + " wasn't found "
+            + " in database " + dbName
+            + " in table " + tableName;}
+
+Core::DataBase::Exist::Exist(
+    const std::string& p_key,
+    const std::string& p_dbName,
+    const std::string& p_tableName
+):
+    Exception(),
+    key(p_key),
+    dbName(p_dbName),
+    tableName(p_tableName) {}
+
+std::string Core::DataBase::Exist::getMessage() const {
+    return "An attempt to insert element with key " + key
+            + " to database " + dbName
+            + " to table " + tableName
+            + " but it already has an element with given id";
+}
+
+Core::DataBase::Unknown::Unknown(
+    const std::string& p_dbName,
+    const std::string& message,
+    const std::optional<std::string>& p_tableName
+):
+    Exception(),
+    dbName(p_dbName),
+    tableName(p_tableName),
+    msg(message) {}
+
+std::string Core::DataBase::Unknown::getMessage() const
+{
+    std::string result = "Unknown error in database " + dbName;
+    if (tableName.has_value()) {
+        result += " in table " + tableName.value();
+    }
+    result += ": " + msg;
+    return result;
+}

exceptions.h

@@ -24,82 +24,64 @@ namespace Core {
 
 class DataBase::Directory: public Utils::Exception {
 public:
-    Directory(const std::string& p_path):Exception(), path(p_path){}
+    Directory(const std::string& path);
 
-    std::string getMessage() const{return "Can't create directory for database at " + path;}
+    std::string getMessage() const;
 private:
     std::string path;
 };
 
 class DataBase::Closed : public Utils::Exception {
 public:
-    Closed(const std::string& op, const std::string& acc):Exception(), operation(op), account(acc){}
+    Closed(const std::string& p_operation, const std::string& dbName, const std::string& tableName);
 
-    std::string getMessage() const{return "An attempt to perform operation " + operation + " on closed archive for " + account;}
+    std::string getMessage() const;
 private:
     std::string operation;
-    std::string account;
+    std::string dbName;
+    std::string tableName;
 };
 
 class DataBase::Opened : public Utils::Exception {
 public:
-    Opened(const std::string& tn):Exception(), tableName(tn){}
+    Opened(const std::string& dbName, const std::string& tableName);
 
-    std::string getMessage() const{return "An attempt to add table " + tableName + " but it's impossible to do if the DataBase is already opened";}
+    std::string getMessage() const;
 private:
+    std::string dbName;
     std::string tableName;
 };
 
 class DataBase::NotFound : public Utils::Exception {
 public:
-    NotFound(const std::string& k, const std::string& acc):Exception(), key(k), account(acc){}
+    NotFound(const std::string& key, const std::string& dbName, const std::string& tableName);
 
-    std::string getMessage() const{return "Element for id " + key + " wasn't found in database " + account;}
+    std::string getMessage() const;
 private:
     std::string key;
-    std::string account;
+    std::string dbName;
-};
+    std::string tableName;
-
-class DataBase::Empty : public Utils::Exception {
-public:
-    Empty(const std::string& acc):Exception(), account(acc){}
-
-    std::string getMessage() const{return "An attempt to read ordered elements from database " + account + " but it's empty";}
-private:
-    std::string account;
 };
 
 class DataBase::Exist : public Utils::Exception {
 public:
-    Exist(const std::string& acc, const std::string& p_key):Exception(), account(acc), key(p_key){}
+    Exist(const std::string& key, const std::string& dbName, const std::string& tableName);
 
-    std::string getMessage() const{return "An attempt to insert element " + key + " to database " + account + " but it already has an element with given id";}
+    std::string getMessage() const;
 private:
-    std::string account;
     std::string key;
-};
+    std::string dbName;
-
+    std::string tableName;
-class DataBase::NoAvatar : public Utils::Exception {
-public:
-    NoAvatar(const std::string& el, const std::string& res):Exception(), element(el), resource(res){
-        if (resource.size() == 0) {
-            resource = "for himself";
-        }
-    }
-
-    std::string getMessage() const{return "Element " + element + " has no avatar for " + resource ;}
-private:
-    std::string element;
-    std::string resource;
 };
 
 class DataBase::Unknown : public Utils::Exception {
 public:
-    Unknown(const std::string& acc, const std::string& message):Exception(), account(acc), msg(message){}
+    Unknown(const std::string& dbName, const std::string& message, const std::optional<std::string>& tableName = std::nullopt);
 
-    std::string getMessage() const{return "Unknown error on database " + account + ": " + msg;}
+    std::string getMessage() const;
 private:
-    std::string account;
+    std::string dbName;
+    std::optional<std::string> tableName;
     std::string msg;
 };
 }

main.cpp

@@ -1,8 +1,17 @@
 #include <iostream>
 
-#include <storage.h>
+#include "database.h"
+#include "table.h"
 
 int main(int argc, char **argv) {
-    std::cout << "Hello, world!" << std::endl;
+
+    Core::DataBase base("test1");
+    Core::DataBase::Table<uint32_t, uint32_t>* table1 = base.addTable<uint32_t, uint32_t>("table1");
+    Core::DataBase::Table<QString, QString>* table2 = base.addTable<QString, QString>("table2");
+
+    base.open();
+
+    table1->addRecord(1, 2);
+
     return 0;
 }

table.cpp

@@ -16,9 +16,10 @@
 
 #include "table.h"
 
-Core::DataBase::_Table::_Table(DataBase* parent):
+Core::DataBase::_Table::_Table(const std::string& p_name, DataBase* parent):
     dbi(),
-    db(parent)
+    db(parent),
+    name(p_name)
 {
 }
 

table.h

@@ -23,19 +23,20 @@ namespace Core {
 
 class DataBase::_Table {
 public:
-    _Table(DataBase* parent);
+    _Table(const std::string& name, DataBase* parent);
     virtual ~_Table();
 
 public:
     MDB_dbi dbi;
     DataBase* db;
+    const std::string name;
 };
 
 template <class K, class V>
 class DataBase::Table : private DataBase::_Table {
     friend class DataBase;
 private:
-    Table(DataBase* parent);
+    Table(const std::string& name, DataBase* parent);
     ~Table() override;
 
 public:
@@ -47,6 +48,16 @@ public:
 
 }
 
+MDB_val& operator << (MDB_val& data, const QString& value);
+MDB_val& operator >> (MDB_val& data, QString& value);
+
+MDB_val& operator << (MDB_val& data, const uint32_t& value);
+MDB_val& operator >> (MDB_val& data, uint32_t& value);
+
+namespace std {
+    std::string to_string(const QString& str);
+}
+
 #include "table.hpp"
 
 #endif // CORE_TABLE_H

table.hpp

@@ -18,22 +18,27 @@
 #define CORE_TABLE_HPP
 
 #include "table.h"
+#include "exceptions.h"
 
+template<typename K, typename V>
+Core::DataBase::Table<K, V>::Table(const std::string& p_name, Core::DataBase* parent):
+    _Table(p_name, parent)
+{
+}
+
+template<typename K, typename V>
+Core::DataBase::Table<K, V>::~Table() {
+}
 
 template<typename K, typename V>
 void Core::DataBase::Table<K, V>::addRecord(const K& key, const V& value) {
     if (!db->opened) {
-        throw Closed("addRecord", db->name);
+        throw Closed("addRecord", db->name, name);
     }
-    QByteArray ba;
-    QDataStream ds(&ba, QIODevice::WriteOnly);
-    ds << value;
 
     MDB_val lmdbKey, lmdbData;
     lmdbKey << key;
-
+    lmdbData << value;
-    lmdbData.mv_size = ba.size();
-    lmdbData.mv_data = (uint8_t*)ba.data();
     MDB_txn *txn;
     mdb_txn_begin(db->environment, NULL, 0, &txn);
     int rc;
@@ -41,13 +46,117 @@ void Core::DataBase::Table<K, V>::addRecord(const K& key, const V& value) {
     if (rc != 0) {
         mdb_txn_abort(txn);
         if (rc == MDB_KEYEXIST) {
-            throw Exist(db->name, std::to_string(key));
+            throw Exist(std::to_string(key), db->name, name);
         } else {
-            throw Unknown(db->name, mdb_strerror(rc));
+            throw Unknown(db->name, mdb_strerror(rc), name);
         }
     } else {
         mdb_txn_commit(txn);
     }
 }
 
+
+
+template<typename K, typename V>
+void Core::DataBase::Table<K, V>::changeRecord(const K& key, const V& value) {
+    if (!db->opened) {
+        throw Closed("changeRecord", db->name, name);
+    }
+
+    MDB_val lmdbKey, lmdbData;
+    lmdbKey << key;
+    lmdbData << value;
+    MDB_txn *txn;
+    mdb_txn_begin(db->environment, NULL, 0, &txn);
+    int rc;
+    rc = mdb_put(txn, dbi, &lmdbKey, &lmdbData, 0);
+    if (rc != 0) {
+        mdb_txn_abort(txn);
+        if (rc) {
+            throw Unknown(db->name, mdb_strerror(rc), name);
+        }
+    } else {
+        mdb_txn_commit(txn);
+    }
+}
+
+template<typename K, typename V>
+V Core::DataBase::Table<K, V>::getRecord(const K& key) const {
+    if (!db->opened) {
+        throw Closed("getRecord", db->name, name);
+    }
+
+    MDB_val lmdbKey, lmdbData;
+    lmdbKey << key;
+
+    MDB_txn *txn;
+    int rc;
+    mdb_txn_begin(db->environment, NULL, MDB_RDONLY, &txn);
+    rc = mdb_get(txn, dbi, &lmdbKey, &lmdbData);
+    if (rc) {
+        mdb_txn_abort(txn);
+        if (rc == MDB_NOTFOUND) {
+            throw NotFound(std::to_string(key), db->name, name);
+        } else {
+            throw Unknown(db->name, mdb_strerror(rc), name);
+        }
+    } else {
+        V value;
+        lmdbData >> value;
+        mdb_txn_abort(txn);
+
+        return value;
+    }
+}
+
+template<typename K, typename V>
+void Core::DataBase::Table<K, V>::removeRecord(const K& key) {
+    if (!db->opened) {
+        throw Closed("removeRecord", db->name, name);
+    }
+
+    MDB_val lmdbKey;
+    lmdbKey << key;
+
+    MDB_txn *txn;
+    int rc;
+    mdb_txn_begin(db->environment, NULL, 0, &txn);
+    rc = mdb_del(txn, dbi, &lmdbKey, NULL);
+    if (rc) {
+        mdb_txn_abort(txn);
+        if (rc == MDB_NOTFOUND) {
+            throw NotFound(std::to_string(key), db->name, name);
+        } else {
+            throw Unknown(db->name, mdb_strerror(rc), name);
+        }
+    } else {
+        mdb_txn_commit(txn);
+    }
+}
+
+MDB_val& operator << (MDB_val& data, const QString& value) {
+    QByteArray ba = value.toUtf8();
+    data.mv_size = ba.size();
+    data.mv_data = ba.data();
+    return data;
+}
+MDB_val& operator >> (MDB_val& data, QString& value) {
+    value = QString::fromUtf8((const char*)data.mv_data, data.mv_size);
+    return data;
+}
+
+MDB_val& operator << (MDB_val& data, const uint32_t& value) {
+    data.mv_size = 4;
+    data.mv_data = &value;
+    return data;
+}
+MDB_val& operator >> (MDB_val& data, uint32_t& value) {
+    std::memcpy(&value, data.mv_data, data.mv_size);
+    return data;
+}
+
+std::string std::to_string(const QString& str) {
+    return str.toStdString();
+}
+
 #endif //CORE_TABLE_HPP