fix(filter): save parser positions when compiling

Use parser positions saved in ast nodes as a compiler position. That
way, if any part of compilation throws an exception, the caller can
call get_pos() to retrieve the position of the node that had the
compliation error.

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>

userspace/libsinsp/filter.cpp

@@ -1584,6 +1584,7 @@ sinsp_filter* sinsp_filter_compiler::compile()
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::and_expr* e)
 {
+	m_pos = e->get_pos();
 	bool nested = m_last_boolop != BO_AND;
 	if (nested)
 	{
@@ -1603,6 +1604,7 @@ void sinsp_filter_compiler::visit(libsinsp::filter::ast::and_expr* e)
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::or_expr* e)
 {
+	m_pos = e->get_pos();
 	bool nested = m_last_boolop != BO_OR;
 	if (nested)
 	{
@@ -1622,6 +1624,7 @@ void sinsp_filter_compiler::visit(libsinsp::filter::ast::or_expr* e)
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::not_expr* e)
 {
+	m_pos = e->get_pos();
 	m_last_boolop = (boolop)((uint32_t)m_last_boolop | BO_NOT);
 	m_filter->push_expression(m_last_boolop);
 	m_last_boolop = BO_NONE;
@@ -1631,6 +1634,7 @@ void sinsp_filter_compiler::visit(libsinsp::filter::ast::not_expr* e)
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::unary_check_expr* e)
 {
+	m_pos = e->get_pos();
 	string field = create_filtercheck_name(e->field, e->arg);
 	gen_event_filter_check *check = create_filtercheck(field);
 	m_filter->add_check(check);
@@ -1661,6 +1665,7 @@ static void add_filtercheck_value(gen_event_filter_check *chk, size_t idx, const
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::binary_check_expr* e)
 {
+	m_pos = e->get_pos();
 	string field = create_filtercheck_name(e->field, e->arg);
 	gen_event_filter_check *check = create_filtercheck(field);
 	m_filter->add_check(check);
@@ -1685,6 +1690,7 @@ void sinsp_filter_compiler::visit(libsinsp::filter::ast::binary_check_expr* e)
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::value_expr* e)
 {
+	m_pos = e->get_pos();
 	if (!m_expect_values)
 	{
 		// this ensures that identifiers, such as Falco macros, are not left
@@ -1697,6 +1703,7 @@ void sinsp_filter_compiler::visit(libsinsp::filter::ast::value_expr* e)
 
 void sinsp_filter_compiler::visit(libsinsp::filter::ast::list_expr* e)
 {
+	m_pos = e->get_pos();
 	if (!m_expect_values)
 	{
 		ASSERT(false);

userspace/libsinsp/filter.h

@@ -105,6 +105,8 @@ class SINSP_PUBLIC sinsp_filter_compiler:
 	*/
 	sinsp_filter* compile();
 
+	const libsinsp::filter::ast::pos_info& get_pos() const { return m_pos; }
+
 private:
 	void visit(libsinsp::filter::ast::and_expr*) override;
 	void visit(libsinsp::filter::ast::or_expr*) override;
@@ -118,6 +120,7 @@ class SINSP_PUBLIC sinsp_filter_compiler:
 	std::string create_filtercheck_name(std::string& name, std::string& arg);
 	gen_event_filter_check* create_filtercheck(std::string& field);
 
+	libsinsp::filter::ast::pos_info m_pos;
 	bool m_ttable_only;
 	bool m_expect_values;
 	boolop m_last_boolop;