XPath: Assume that every function can fail and return 0
Propagate the failure to the caller manually. This is a first step to parser structure that does not depend on exceptions or longjmp for error handling (and thus matches the XML parser). To preserve semantics we'll have to convert error code to exception later.
This commit is contained in:
Arseny Kapoulkine
parent
d72c0763f9
commit
7bb433b141
1 changed files with 32 additions and 9 deletions
|
|
@ -11222,6 +11222,7 @@ PUGI__NS_BEGIN
|
|||
_lexer.next();
|
||||
|
||||
xpath_ast_node* n = parse_expression();
|
||||
if (!n) return 0;
|
||||
|
||||
if (_lexer.current() != lex_close_brace)
|
||||
throw_error("Unmatched braces");
|
||||
|
|
@ -11234,12 +11235,11 @@ PUGI__NS_BEGIN
|
|||
case lex_quoted_string:
|
||||
{
|
||||
const char_t* value = alloc_string(_lexer.contents());
|
||||
|
||||
xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_string_constant, xpath_type_string, value);
|
||||
if (!value) return 0;
|
||||
|
||||
_lexer.next();
|
||||
|
||||
return n;
|
||||
return new (alloc_node()) xpath_ast_node(ast_string_constant, xpath_type_string, value);
|
||||
}
|
||||
|
||||
case lex_number:
|
||||
|
|
@ -11249,11 +11249,9 @@ PUGI__NS_BEGIN
|
|||
if (!convert_string_to_number_scratch(_scratch, _lexer.contents().begin, _lexer.contents().end, &value))
|
||||
throw_error_oom();
|
||||
|
||||
xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_number_constant, xpath_type_number, value);
|
||||
|
||||
_lexer.next();
|
||||
|
||||
return n;
|
||||
return new (alloc_node()) xpath_ast_node(ast_number_constant, xpath_type_number, value);
|
||||
}
|
||||
|
||||
case lex_string:
|
||||
|
|
@ -11280,6 +11278,7 @@ PUGI__NS_BEGIN
|
|||
}
|
||||
|
||||
xpath_ast_node* n = parse_expression();
|
||||
if (!n) return 0;
|
||||
|
||||
if (argc < 2) args[argc] = n;
|
||||
else last_arg->set_next(n);
|
||||
|
|
@ -11306,17 +11305,20 @@ PUGI__NS_BEGIN
|
|||
xpath_ast_node* parse_filter_expression()
|
||||
{
|
||||
xpath_ast_node* n = parse_primary_expression();
|
||||
if (!n) return 0;
|
||||
|
||||
while (_lexer.current() == lex_open_square_brace)
|
||||
{
|
||||
_lexer.next();
|
||||
|
||||
xpath_ast_node* expr = parse_expression();
|
||||
if (!expr) return 0;
|
||||
|
||||
if (n->rettype() != xpath_type_node_set)
|
||||
throw_error("Predicate has to be applied to node set");
|
||||
|
||||
n = new (alloc_node()) xpath_ast_node(ast_filter, n, expr, predicate_default);
|
||||
if (!n) return 0;
|
||||
|
||||
if (_lexer.current() != lex_close_square_brace)
|
||||
throw_error("Unmatched square brace");
|
||||
|
|
@ -11461,7 +11463,10 @@ PUGI__NS_BEGIN
|
|||
}
|
||||
|
||||
const char_t* nt_name_copy = alloc_string(nt_name);
|
||||
if (!nt_name_copy) return 0;
|
||||
|
||||
xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_step, set, axis, nt_type, nt_name_copy);
|
||||
if (!n) return 0;
|
||||
|
||||
xpath_ast_node* last = 0;
|
||||
|
||||
|
|
@ -11470,8 +11475,10 @@ PUGI__NS_BEGIN
|
|||
_lexer.next();
|
||||
|
||||
xpath_ast_node* expr = parse_expression();
|
||||
if (!expr) return 0;
|
||||
|
||||
xpath_ast_node* pred = new (alloc_node()) xpath_ast_node(ast_predicate, 0, expr, predicate_default);
|
||||
if (!pred) return 0;
|
||||
|
||||
if (_lexer.current() != lex_close_square_brace)
|
||||
throw_error("Unmatched square brace");
|
||||
|
|
@ -11490,6 +11497,7 @@ PUGI__NS_BEGIN
|
|||
xpath_ast_node* parse_relative_location_path(xpath_ast_node* set)
|
||||
{
|
||||
xpath_ast_node* n = parse_step(set);
|
||||
if (!n) return 0;
|
||||
|
||||
while (_lexer.current() == lex_slash || _lexer.current() == lex_double_slash)
|
||||
{
|
||||
|
|
@ -11497,9 +11505,13 @@ PUGI__NS_BEGIN
|
|||
_lexer.next();
|
||||
|
||||
if (l == lex_double_slash)
|
||||
{
|
||||
n = new (alloc_node()) xpath_ast_node(ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
|
||||
if (!n) return 0;
|
||||
}
|
||||
|
||||
n = parse_step(n);
|
||||
if (!n) return 0;
|
||||
}
|
||||
|
||||
return n;
|
||||
|
|
@ -11514,6 +11526,7 @@ PUGI__NS_BEGIN
|
|||
_lexer.next();
|
||||
|
||||
xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_step_root, xpath_type_node_set);
|
||||
if (!n) return 0;
|
||||
|
||||
// relative location path can start from axis_attribute, dot, double_dot, multiply and string lexemes; any other lexeme means standalone root path
|
||||
lexeme_t l = _lexer.current();
|
||||
|
|
@ -11528,7 +11541,10 @@ PUGI__NS_BEGIN
|
|||
_lexer.next();
|
||||
|
||||
xpath_ast_node* n = new (alloc_node()) xpath_ast_node(ast_step_root, xpath_type_node_set);
|
||||
if (!n) return 0;
|
||||
|
||||
n = new (alloc_node()) xpath_ast_node(ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
|
||||
if (!n) return 0;
|
||||
|
||||
return parse_relative_location_path(n);
|
||||
}
|
||||
|
|
@ -11551,7 +11567,6 @@ PUGI__NS_BEGIN
|
|||
// PrimaryExpr begins with '$' in case of it being a variable reference,
|
||||
// '(' in case of it being an expression, string literal, number constant or
|
||||
// function call.
|
||||
|
||||
if (_lexer.current() == lex_var_ref || _lexer.current() == lex_open_brace ||
|
||||
_lexer.current() == lex_quoted_string || _lexer.current() == lex_number ||
|
||||
_lexer.current() == lex_string)
|
||||
|
|
@ -11572,6 +11587,7 @@ PUGI__NS_BEGIN
|
|||
}
|
||||
|
||||
xpath_ast_node* n = parse_filter_expression();
|
||||
if (!n) return 0;
|
||||
|
||||
if (_lexer.current() == lex_slash || _lexer.current() == lex_double_slash)
|
||||
{
|
||||
|
|
@ -11584,6 +11600,7 @@ PUGI__NS_BEGIN
|
|||
throw_error("Step has to be applied to node set");
|
||||
|
||||
n = new (alloc_node()) xpath_ast_node(ast_step, n, axis_descendant_or_self, nodetest_type_node, 0);
|
||||
if (!n) return 0;
|
||||
}
|
||||
|
||||
// select from location path
|
||||
|
|
@ -11598,6 +11615,7 @@ PUGI__NS_BEGIN
|
|||
|
||||
// precedence 7+ - only parses union expressions
|
||||
xpath_ast_node* n = parse_expression(7);
|
||||
if (!n) return 0;
|
||||
|
||||
return new (alloc_node()) xpath_ast_node(ast_op_negate, xpath_type_number, n);
|
||||
}
|
||||
|
|
@ -11682,12 +11700,14 @@ PUGI__NS_BEGIN
|
|||
_lexer.next();
|
||||
|
||||
xpath_ast_node* rhs = parse_path_or_unary_expression();
|
||||
if (!rhs) return 0;
|
||||
|
||||
binary_op_t nextop = binary_op_t::parse(_lexer);
|
||||
|
||||
while (nextop.asttype != ast_unknown && nextop.precedence > op.precedence)
|
||||
{
|
||||
rhs = parse_expression_rec(rhs, nextop.precedence);
|
||||
if (!rhs) return 0;
|
||||
|
||||
nextop = binary_op_t::parse(_lexer);
|
||||
}
|
||||
|
|
@ -11696,6 +11716,7 @@ PUGI__NS_BEGIN
|
|||
throw_error("Union operator has to be applied to node sets");
|
||||
|
||||
lhs = new (alloc_node()) xpath_ast_node(op.asttype, op.rettype, lhs, rhs);
|
||||
if (!lhs) return 0;
|
||||
|
||||
op = binary_op_t::parse(_lexer);
|
||||
}
|
||||
|
|
@ -11724,6 +11745,7 @@ PUGI__NS_BEGIN
|
|||
xpath_ast_node* parse_expression(int limit = 0)
|
||||
{
|
||||
xpath_ast_node* n = parse_path_or_unary_expression();
|
||||
if (!n) return 0;
|
||||
|
||||
return parse_expression_rec(n, limit);
|
||||
}
|
||||
|
|
@ -11734,13 +11756,14 @@ PUGI__NS_BEGIN
|
|||
|
||||
xpath_ast_node* parse()
|
||||
{
|
||||
xpath_ast_node* result = parse_expression();
|
||||
xpath_ast_node* n = parse_expression();
|
||||
if (!n) return 0;
|
||||
|
||||
// check if there are unparsed tokens left
|
||||
if (_lexer.current() != lex_eof)
|
||||
throw_error("Incorrect query");
|
||||
|
||||
return result;
|
||||
return n;
|
||||
}
|
||||
|
||||
static xpath_ast_node* parse(const char_t* query, xpath_variable_set* variables, xpath_allocator* alloc, xpath_parse_result* result)
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue