Handle the case when the driver tries to save more data than the buffer is big enough, and doesn't bother to mention it

Use the driver's bindSize as a hint as to how much buffer to allocate up front

3 files changed, 23 insertions, 19 deletions

diff --git a/libodbcpp/column.cpp b/libodbcpp/column.cpp
index b041bd4..a34946a 100644
--- a/libodbcpp/column.cpp
+++ b/libodbcpp/column.cpp
@@ -17,13 +17,14 @@ ODBC::Column::~Column()
 {
 }
 
-void
-ODBC::Column::resize(SQLHANDLE)
+bool
+ODBC::Column::resize()
 {
+	return false;
 }
 
-void
-ODBC::CharArrayColumn::resize(SQLHANDLE)
+bool
+ODBC::CharArrayColumn::resize()
 {
 	if (bindLen >= SQLLEN(data.size())) {
 		data.resize(bindLen + 1);
@@ -32,12 +33,9 @@ ODBC::CharArrayColumn::resize(SQLHANDLE)
 			paramBound = false;
 			Param::bind();
 		}
+		return true;
 	}
-}
-
-void
-ODBC::Column::onScroll()
-{
+	return false;
 }
 
 bool
diff --git a/libodbcpp/column.h b/libodbcpp/column.h
index 71118f8..e981a14 100644
--- a/libodbcpp/column.h
+++ b/libodbcpp/column.h
@@ -4,6 +4,7 @@
 #include "../libdbpp/column.h"
 #include <typeinfo>
 #include <glibmm/ustring.h>
+#include <algorithm>
 #include "bind.h"
 #include "param.h"
 
@@ -16,8 +17,7 @@ namespace ODBC {
 			void bind();
 			virtual void * rwDataAddress() = 0;
 			void rebind(DB::Command *, unsigned int idx) const;
-			virtual void resize(SQLHANDLE);
-			virtual void onScroll();
+			virtual bool resize();
 
 			virtual operator int () const { throw std::bad_cast(); }
 			virtual operator long () const { throw std::bad_cast(); }
@@ -45,11 +45,11 @@ namespace ODBC {
 	class CharArrayColumn : public Column, public Param {
 		public:
 			typedef std::vector<char> CharArray;
-			CharArrayColumn(SelectCommand * sc, const Glib::ustring & n, unsigned int i) :
+			CharArrayColumn(SelectCommand * sc, const Glib::ustring & n, unsigned int i, SQLULEN sizeHint) :
 				DB::Column(n, i),
 				Column(sc, n, i)
 			{
-				data.resize(256);
+				data.resize(std::max<SQLULEN>(sizeHint, 64) + 1);
 			}
 			virtual SQLSMALLINT ctype() const { return SQL_C_CHAR; }
 			virtual SQLSMALLINT stype() const { return SQL_CHAR; }
@@ -58,7 +58,7 @@ namespace ODBC {
 			virtual const void * dataAddress() const { return &data.front(); }
 			virtual void * rwDataAddress() { return &data.front(); }
 			void operator=(const Glib::ustring & d);
-			void resize(SQLHANDLE);
+			bool resize();
 			virtual operator std::string () const { return std::string(&data.front(), bindLen); }
 			virtual operator Glib::ustring () const { return std::string(&data.front(), bindLen); }
 			virtual void apply(DB::HandleField &) const;
diff --git a/libodbcpp/selectcommand.cpp b/libodbcpp/selectcommand.cpp
index 32978a4..f44472f 100644
--- a/libodbcpp/selectcommand.cpp
+++ b/libodbcpp/selectcommand.cpp
@@ -49,7 +49,7 @@ ODBC::SelectCommand::fetch(SQLSMALLINT orientation, SQLLEN offset)
 				if (SQL_SUCCEEDED(diagrc)) {
 					if (!strncmp((const char*)sqlstatus, "01004", 5)) {
 						for (Columns::iterator i = columns.begin(); i != columns.end(); i++) {
-							(*i)->resize(hStmt);
+							(*i)->resize();
 						}
 						return fetch(SQL_FETCH_RELATIVE, 0);
 					}
@@ -59,10 +59,16 @@ ODBC::SelectCommand::fetch(SQLSMALLINT orientation, SQLLEN offset)
 				}
 			}
 		case SQL_SUCCESS:
-			for (Columns::iterator i = columns.begin(); i != columns.end(); i++) {
-				(*i)->onScroll();
+			{
+				bool resized = false;
+				for (Columns::iterator i = columns.begin(); i != columns.end(); i++) {
+					resized |= (*i)->resize();
+				}
+				if (resized) {
+					return fetch(SQL_FETCH_RELATIVE, 0);
+				}
+				return true;
 			}
-			return true;
 		case SQL_NO_DATA:
 			return false;
 	}
@@ -115,7 +121,7 @@ ODBC::SelectCommand::execute()
 				columns[col] = new TimeStampColumn(this, colName, col);
 				break;
 			default:
-				columns[col] = new CharArrayColumn(this, colName, col);
+				columns[col] = new CharArrayColumn(this, colName, col, bindSize);
 				break;
 		};
 		columns[col]->bind();