Add RowIterator and Row class fundation

Author: Kacperos155

CMakeLists.txt

@@ -105,6 +105,7 @@ set(SQLITECPP_SRC
  ${PROJECT_SOURCE_DIR}/src/Column.cpp
  ${PROJECT_SOURCE_DIR}/src/Database.cpp
  ${PROJECT_SOURCE_DIR}/src/Exception.cpp
+ ${PROJECT_SOURCE_DIR}/src/Row.cpp
  ${PROJECT_SOURCE_DIR}/src/RowExecutor.cpp
  ${PROJECT_SOURCE_DIR}/src/Savepoint.cpp
  ${PROJECT_SOURCE_DIR}/src/Statement.cpp
@@ -120,6 +121,7 @@ set(SQLITECPP_INC
  ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/Column.h
  ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/Database.h
  ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/Exception.h
+ ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/Row.h
  ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/RowExecutor.h
  ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/Savepoint.h
  ${PROJECT_SOURCE_DIR}/include/SQLiteCpp/Statement.h

include/SQLiteCpp/Column.h

@@ -54,11 +54,7 @@ class Column
      * @param[in] aStmtPtr  Shared pointer to the prepared SQLite Statement Object.
      * @param[in] aIndex    Index of the column in the row of result, starting at 0
      */
-    explicit Column(const Statement::TStatementPtr& aStmtPtr, int aIndex);
-
-    // default destructor: the finalization will be done by the destructor of the last shared pointer
-    // default copy constructor and assignment operator are perfectly suited :
-    // they copy the Statement::Ptr which in turn increments the reference counter.
+    explicit Column(const RowExecutor::TStatementPtr& aStmtPtr, int aIndex);
 
     /**
      * @brief Return a pointer to the named assigned to this result column (potentially aliased)
@@ -252,7 +248,7 @@ class Column
     }
 
 private:
-    Statement::TStatementPtr    mStmtPtr;  ///< Shared Pointer to the prepared SQLite Statement Object
+    RowExecutor::TStatementPtr  mStmtPtr;  ///< Shared Pointer to the prepared SQLite Statement Object
     int                         mIndex;    ///< Index of the column in the row of result, starting at 0
 };
 
@@ -283,9 +279,10 @@ T Statement::getColumns()
 template<typename T, const int... Is>
 T Statement::getColumns(const std::integer_sequence<int, Is...>)
 {
-    return T{Column(getStatement(), Is)...};
+    return T{ Column(getStatement(), Is)... };
 }
 
 #endif
 
+
 }  // namespace SQLite

include/SQLiteCpp/Row.h

@@ -0,0 +1,56 @@
+/**
+ * @file    Row.h
+ * @ingroup SQLiteCpp
+ * @brief   TODO:
+ *
+ * Copyright (c) 2015 Shibao HONG ([email protected])
+ * Copyright (c) 2015-2021 Sebastien Rombauts ([email protected])
+ *
+ * Distributed under the MIT License (MIT) (See accompanying file LICENSE.txt
+ * or copy at http://opensource.org/licenses/MIT)
+ */
+#pragma once
+
+#include <SQLiteCpp/RowExecutor.h>
+
+#include <string>
+
+namespace SQLite
+{
+
+
+class Row
+{
+public:
+    Row(RowExecutor::TStatementWeakPtr apRow, std::size_t aID);
+
+    std::size_t getRowNumber() const
+    {
+        return ID;
+    }
+
+    /**
+     * @brief Test if the column value is NULL
+     *
+     * @param[in] aIndex    Index of the column, starting at 0
+     *
+     * @return true if the column value is NULL
+     *
+     *  Throw an exception if the specified index is out of the [0, getColumnCount()) range.
+     */
+    bool    isColumnNull(const int aIndex) const;
+
+    /**
+     * @brief Return a pointer to the text value (NULL terminated string) of the column.
+     *
+     * @warning The value pointed at is only valid while the statement is valid (ie. not finalized),
+     *          thus you must copy it before using it beyond its scope (to a std::string for instance).
+     */
+    const char* getText(uint32_t aColumnID) const noexcept;
+
+private:
+    RowExecutor::TStatementWeakPtr mpRow;
+    std::size_t ID;
+};
+
+}  // namespace SQLite

include/SQLiteCpp/RowExecutor.h

@@ -1,7 +1,7 @@
 /**
  * @file    RowExecutor.h
  * @ingroup SQLiteCpp
- * @brief   TODO:
+ * @brief   Step executor for SQLite prepared Statement Object
  *
  * Copyright (c) 2015 Shibao HONG ([email protected])
  * Copyright (c) 2015-2021 Sebastien Rombauts ([email protected])
@@ -45,6 +45,11 @@ class RowExecutor
     /// Type to store columns names and indexes
     using TColumnsMap = std::map<std::string, int, std::less<>>;
 
+    RowExecutor(const RowExecutor&) = delete;
+    RowExecutor(RowExecutor&&) = default;
+    RowExecutor& operator=(const RowExecutor&) = delete;
+    RowExecutor& operator=(RowExecutor&&) = default;
+
     /// Reset the statement to make it ready for a new execution. Throws an exception on error.
     void reset();
 
@@ -130,17 +135,17 @@ class RowExecutor
     int getChanges() const noexcept;
 
     /// Return the number of columns in the result set returned by the prepared statement
-    int getColumnCount() const
+    int getColumnCount() const noexcept
     {
         return mColumnCount;
     }
     /// true when a row has been fetched with executeStep()
-    bool hasRow() const
+    bool hasRow() const noexcept
     {
         return mbHasRow;
     }
     /// true when the last executeStep() had no more row to fetch
-    bool isDone() const
+    bool isDone() const noexcept
     {
         return mbDone;
     }
@@ -167,7 +172,10 @@ class RowExecutor
      *
      * @return raw pointer to Statement Object
      */
-    TStatementPtr getStatement() const noexcept;
+    TStatementPtr getStatement() const noexcept
+    {
+        return mpStatement;
+    }
 
     /**
      * @brief Return a prepared SQLite Statement Object.
@@ -176,6 +184,19 @@ class RowExecutor
      * @return raw pointer to Prepared Statement Object
      */
     sqlite3_stmt* getPreparedStatement() const;
+    
+    /**
+     * @brief Return a prepared SQLite Statement Object.
+     *
+     * Throw an exception if the statement object was not prepared.
+     * @return raw pointer to Prepared Statement Object
+     */
+    TRowWeakPtr getExecutorWeakPtr() const
+    {
+        return mpRowExecutor;
+    }
+
+    ////////////////////////////////////////////////////////////////////////////
 
     /**
      * @brief Check if a return code equals SQLITE_OK, else throw a SQLite::Exception with the SQLite error message
@@ -222,9 +243,13 @@ class RowExecutor
     sqlite3* mpSQLite{}; //!< Pointer to SQLite Database Connection Handle
     TStatementPtr mpStatement{}; //!< Shared Pointer to the prepared SQLite Statement Object
 
-    int mColumnCount{ 0 }; //!< Number of columns in the result of the prepared statement
-    bool mbHasRow{ false }; //!< true when a row has been fetched with executeStep()
-    bool mbDone{ false }; //!< true when the last executeStep() had no more row to fetch
+    /// Shared Pointer to this object.
+    /// Allows RowIterator to execute next step
+    TRowPtr mpRowExecutor{};
+
+    int mColumnCount = 0; //!< Number of columns in the result of the prepared statement
+    bool mbHasRow = false; //!< true when a row has been fetched with executeStep()
+    bool mbDone = false; //!< true when the last executeStep() had no more row to fetch
 
     /// Map of columns index by name (mutable so getColumnIndex can be const)
     mutable TColumnsMap mColumnNames{};

include/SQLiteCpp/Statement.h

@@ -1,7 +1,7 @@
 /**
  * @file    Statement.h
  * @ingroup SQLiteCpp
- * @brief   A prepared SQLite Statement is a compiled SQL query ready to be executed, pointing to a row of result.
+ * @brief   A prepared SQLite Statement Object binder and Column getter.
  *
  * Copyright (c) 2012-2021 Sebastien Rombauts ([email protected])
  *
@@ -541,8 +541,64 @@ class Statement : public RowExecutor
     /// Return the number of bind parameters in the statement
     int getBindParameterCount() const noexcept;
 
+    ////////////////////////////////////////////////////////////////////////////
+
+    class RowIterator
+    {
+    public:
+        using iterator_category = std::input_iterator_tag;
+        using value_type = Row;
+        using reference = const Row&;
+        using pointer = const Row*;
+        using difference_type = std::ptrdiff_t;
+
+        RowIterator() = default;
+        RowIterator(TStatementWeakPtr apStatement, TRowWeakPtr apRow, uint16_t aID) :
+            mpStatement(apStatement), mpRow(apRow), mID(aID), mRow(apStatement, aID) {}
+
+        reference operator*() const
+        {
+            return mRow;
+        }
+        pointer operator->() const noexcept
+        {
+            return &mRow;
+        }
+
+        reference operator++() noexcept
+        {
+            mRow = Row(mpStatement, ++mID);
+            advance();
+            return mRow;
+        }
+        value_type operator++(int)
+        {
+            Row copy{ mRow };
+            mRow = Row(mpStatement, ++mID);
+            advance();
+            return copy;
+        }
+
+        bool operator==(const RowIterator& aIt) const;
+        bool operator!=(const RowIterator& aIt) const
+        {
+            return !(*this == aIt);
+        }
+
+    private:
+        void advance() noexcept;
+
+        TStatementWeakPtr mpStatement{};
+        TRowWeakPtr mpRow{};
+        uint16_t mID{};
+        Row mRow{ mpStatement, mID };
+    };
+
+    RowIterator begin();
+    RowIterator end();
+
 private:
-    std::string             mQuery;                 //!< UTF-8 SQL Query
+    std::string mQuery; //!< UTF-8 SQL Query,
 };
 
 

src/Column.cpp

@@ -26,7 +26,7 @@ const int Null      = SQLITE_NULL;
 
 
 // Encapsulation of a Column in a row of the result pointed by the prepared Statement.
-Column::Column(const Statement::TStatementPtr& aStmtPtr, int aIndex) :
+Column::Column(const RowExecutor::TStatementPtr& aStmtPtr, int aIndex) :
     mStmtPtr(aStmtPtr),
     mIndex(aIndex)
 {

src/Row.cpp

@@ -0,0 +1,41 @@
+/**
+ * @file    Row.cpp
+ * @ingroup SQLiteCpp
+ * @brief   TODO:
+ *
+ * Copyright (c) 2015 Shibao HONG ([email protected])
+ * Copyright (c) 2015-2021 Sebastien Rombauts ([email protected])
+ *
+ * Distributed under the MIT License (MIT) (See accompanying file LICENSE.txt
+ * or copy at http://opensource.org/licenses/MIT)
+ */
+#include <SQLiteCpp/Row.h>
+
+#include <SQLiteCpp/Exception.h>
+
+#include <sqlite3.h>
+
+namespace SQLite
+{
+
+
+    Row::Row(RowExecutor::TStatementWeakPtr apRow, std::size_t aID) :
+        mpRow(apRow), ID(aID)
+    {
+    }
+
+    bool Row::isColumnNull(const int aIndex) const
+    {
+        return false;
+    }
+
+    const char* Row::getText(uint32_t aColumnID) const noexcept
+    {
+        auto statement = mpRow.lock();
+
+
+        auto pText = reinterpret_cast<const char*>(sqlite3_column_text(statement.get(), aColumnID));
+        return (pText ? pText : "");
+    }
+
+}  // namespace SQLite

src/RowExecutor.cpp

@@ -1,7 +1,7 @@
 /**
  * @file    RowExecutor.cpp
  * @ingroup SQLiteCpp
- * @brief   TODO:
+ * @brief   Step executor for SQLite prepared Statement Object
  *
  * Copyright (c) 2015 Shibao HONG ([email protected])
  * Copyright (c) 2015-2021 Sebastien Rombauts ([email protected])
@@ -24,6 +24,10 @@ namespace SQLite
     {
         prepareStatement(aQuery);
         createColumnInfo();
+
+        mpRowExecutor.swap(TRowPtr(this, [](const RowExecutor* const) {
+            //empty destructor to make shared_ptr without ownership
+            }));
     }
 
     void SQLite::RowExecutor::prepareStatement(const std::string& aQuery)
@@ -165,12 +169,6 @@ namespace SQLite
         return sqlite3_errmsg(mpSQLite);
     }
 
-    // Return std::shared_ptr with SQLite statement object
-    RowExecutor::TStatementPtr RowExecutor::getStatement() const noexcept
-    {
-        return mpStatement;
-    }
-
     // Return prepered SQLite statement object or throw
     sqlite3_stmt* RowExecutor::getPreparedStatement() const
     {