From 56fbd20635752f496ffdb981cb00b2a55b0ef886 Mon Sep 17 00:00:00 2001
From: Eelke Klein <eelke@eelkeklein.nl>
Date: Wed, 25 Jan 2017 06:50:57 +0100
Subject: [PATCH] Database layer now support automatic type conversion and the
 Result has iterator support.

This also means you can use for each to loop through a result.
---
 PgsqlConn.cpp |  28 ++++++++++
 PgsqlConn.h   | 151 ++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 155 insertions(+), 24 deletions(-)

diff --git a/PgsqlConn.cpp b/PgsqlConn.cpp
index a5ad6e2..411033f 100644
--- a/PgsqlConn.cpp
+++ b/PgsqlConn.cpp
@@ -46,6 +46,26 @@ ErrorDetails ErrorDetails::createErrorDetailsFromPGresult(const PGresult *result
 	return r;
 }
 
+
+bool Row::next()
+{
+	if (m_row < m_result.getRows()) {
+		++m_row;
+		return true;
+	}
+	return false;
+}
+
+Value Row::get(int col) const
+{
+	return m_result.get(col, m_row);
+}
+
+//Value Row::get(const char *colname) const
+//{
+
+//}
+
 Result::Result(PGresult *res)
 	: result(res)
 {
@@ -165,6 +185,14 @@ const char * Result::getVal(int col, int row) const
     return PQgetvalue(result, row, col);
 }
 
+Value Result::get(int col, int row) const
+{
+	return Value(
+		PQgetvalue(result, row, col),
+		PQftype(result, col)
+		);
+}
+
 Oid Result::type(int col) const
 {
 	return PQftype(result, col);
diff --git a/PgsqlConn.h b/PgsqlConn.h
index e7d2e07..2161fd6 100644
--- a/PgsqlConn.h
+++ b/PgsqlConn.h
@@ -6,6 +6,7 @@
 #include <cassert>
 #include <QString>
 
+#include <codecvt>
 #include <memory>
 
 namespace Pgsql {
@@ -66,37 +67,127 @@ namespace Pgsql {
 		std::string sourceFunction;
 	};
 
+	class Value {
+	public:
+		Value(const char *val, Oid typ)
+			: m_val(val), m_typ(typ)
+		{}
+
+		QString asQString() const
+		{
+			return QString::fromUtf8(m_val);
+		}
+
+		operator QString() const
+		{
+			return QString::fromUtf8(m_val);
+		}
+
+		operator std::string() const
+		{
+			return m_val;
+		}
+
+		operator short() const
+		{
+			return (short)std::atoi(m_val);
+		}
+
+		operator int() const
+		{
+			return std::atoi(m_val);
+		}
+
+		operator Oid() const
+		{
+			return operator int();
+		}
+
+		operator __int64() const
+		{
+			return strtoull(m_val, nullptr, 10);
+		}
+
+		operator bool() const
+		{
+			return strcmp(m_val, "t") == 0;
+		}
+
+	private:
+		const char *m_val;
+		Oid m_typ;
+
+	};
+
+
+	class Result;
+
+	class Row {
+	public:
+		Row(const Result &result, int row)
+			: m_result(result)
+			, m_row(row)
+		{}
+
+		bool next();
+		bool operator==(const Row& rhs)
+		{
+			return &m_result == &rhs.m_result
+					&& m_row == rhs.m_row;
+		}
+
+		Value get(int col) const;
+		//Value get(const char *colname) const;
+		//bool get(int col, QString &s);
+	private:
+		const Result& m_result;
+		int m_row;
+	};
+
 	/** Non-copyable but movable wrapper for a postgresql result. */
 	class Result {
 	public:
-//		class iterator {
-//		public:
-//			iterator(Result &r, int rw)
-//				: result(r), row(rw)
-//			{}
+		class const_iterator {
+		public:
+			const_iterator(const Result &r, int rw)
+				: m_row(r, rw)
+			{}
 
-//			iterator operator++()
-//			{
-//				iterator t(*this);
-//				++row;
-//				return t;
-//			}
+			const_iterator operator++()
+			{
+				const_iterator t(*this);
+				m_row.next();
+				return t;
+			}
 
-//			iterator& operator++(int)
-//			{
-//				++row;
-//				return *this;
-//			}
+			const_iterator& operator++(int)
+			{
+				m_row.next();
+				return *this;
+			}
 
-//			bool operator!=(const iterator &rhs)
-//			{
-//				assert()
-//			}
+			bool operator==(const const_iterator &rhs)
+			{
+				return m_row == rhs.m_row;
+			}
 
-//		private:
-//			Result &result;
-//			int row;
-//		};
+			bool operator!=(const const_iterator &rhs)
+			{
+				return !operator==(rhs);
+			}
+
+			const Row& operator*()
+			{
+				return m_row;
+			}
+			const Row& operator->()
+			{
+				return m_row;
+			}
+
+		private:
+			Row m_row;
+		};
 
 		Result() = default;
 		Result(PGresult *result);
@@ -122,7 +213,15 @@ namespace Pgsql {
 		/** Retrieves all the error fields. */
 		ErrorDetails diagDetails();
 
+		const_iterator begin() const
+		{
+			return const_iterator(*this, 0);
+		}
 
+		const_iterator end() const
+		{
+			return const_iterator(*this, getRows());
+		}
 
 		int tuplesAffected() const;
 		int getRows() const;
@@ -131,6 +230,7 @@ namespace Pgsql {
 		const char* const getColName(int idx) const;
 
 		const char * getVal(int col, int row) const;
+		Value get(int col, int row) const;
 		Oid type(int col) const;
 		bool null(int col, int row) const;
 
@@ -297,3 +397,6 @@ namespace Pgsql {
 //
 //	};
 }
+
+
+