progress on record fetch

backends/sqlite/src/sqlite_connection.cpp

@@ -37,14 +37,37 @@ bool sqlite_connection::is_open()
   return sqlite_db_ != nullptr;
 }
 
+struct fetch_context
+{
+  sql::record prototype;
+  sqlite_query_result::rows rows;
+};
+
 int sqlite_connection::parse_result(void* param, int column_count, char** values, char** columns)
 {
-  auto *result = static_cast<sqlite_query_result*>(param);
-  result->push_back(values, column_count);
+  auto *context = static_cast<fetch_context*>(param);
 
-  sql::record prototype;
+  sqlite_query_result::columns column;
   for(int i = 0; i < column_count; ++i) {
-    prototype.append(sql::column{columns[i]});
+    // copy and store column data;
+    if (values[i] == nullptr) {
+      auto val = new char[1];
+      val[0] = '\0';
+      column.push_back(val);
+    } else {
+      size_t size = strlen(values[i]);
+      auto val = new char[size + 1];
+      std::memcpy(val, values[i], size);
+      val[size] = '\0';
+      column.push_back(val);
+    }
+  }
+  context->rows.emplace_back(column);
+
+  if (context->prototype.empty()) {
+    for(int i = 0; i < column_count; ++i) {
+      context->prototype.append(sql::column{columns[i]});
+    }
   }
 
   return 0;
@@ -62,13 +85,13 @@ size_t sqlite_connection::execute(const std::string &stmt)
 
 std::unique_ptr<sql::query_result_impl> sqlite_connection::fetch(const std::string &stmt)
 {
-  auto result = std::make_unique<sqlite_query_result>();
+  fetch_context context;
   char *errmsg = nullptr;
-  const int ret = sqlite3_exec(sqlite_db_, stmt.c_str(), parse_result, result.get(), &errmsg);
+  const int ret = sqlite3_exec(sqlite_db_, stmt.c_str(), parse_result, &context, &errmsg);
 
   throw_sqlite_error(ret, sqlite_db_, "sqlite", stmt);
 
-  return std::move(result);
+  return std::move(std::make_unique<sqlite_query_result>(std::move(context.prototype), std::move(context.rows)));
 }
 
 void sqlite_connection::prepare(const std::string &stmt)