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Implement copy ctor/assignment for xpath_variable_set

xpath_variable_set is essentially an associative container; it's about time it
became copyable.

Implementation is slightly tricky due to out of memory handling. Both copy ctor
and assignment operator have strong exception guarantee (even if exceptions are
disabled! which translates to "roll back on allocation errors").
This commit is contained in:
Arseny Kapoulkine 2015-04-15 23:22:31 -07:00
parent 70a78b2fa5
commit cbf3807ad4
3 changed files with 160 additions and 7 deletions

View File

@ -7758,6 +7758,28 @@ PUGI__NS_BEGIN
}
}
PUGI__FN bool copy_xpath_variable(xpath_variable* lhs, const xpath_variable* rhs)
{
switch (rhs->type())
{
case xpath_type_node_set:
return lhs->set(static_cast<const xpath_variable_node_set*>(rhs)->value);
case xpath_type_number:
return lhs->set(static_cast<const xpath_variable_number*>(rhs)->value);
case xpath_type_string:
return lhs->set(static_cast<const xpath_variable_string*>(rhs)->value);
case xpath_type_boolean:
return lhs->set(static_cast<const xpath_variable_boolean*>(rhs)->value);
default:
assert(!"Invalid variable type");
return false;
}
}
PUGI__FN bool get_variable_scratch(char_t (&buffer)[32], xpath_variable_set* set, const char_t* begin, const char_t* end, xpath_variable** out_result)
{
size_t length = static_cast<size_t>(end - begin);
@ -11277,7 +11299,46 @@ namespace pugi
}
}
PUGI__FN xpath_variable* xpath_variable_set::find(const char_t* name) const
PUGI__FN xpath_variable_set::xpath_variable_set(const xpath_variable_set& rhs)
{
for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i)
_data[i] = 0;
_assign(rhs);
}
PUGI__FN xpath_variable_set& xpath_variable_set::operator=(const xpath_variable_set& rhs)
{
if (this == &rhs) return *this;
_assign(rhs);
return *this;
}
PUGI__FN void xpath_variable_set::_assign(const xpath_variable_set& rhs)
{
xpath_variable_set temp;
for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i)
if (rhs._data[i] && !_clone(rhs._data[i], &temp._data[i]))
return;
_swap(temp);
}
PUGI__FN void xpath_variable_set::_swap(xpath_variable_set& rhs)
{
for (size_t i = 0; i < sizeof(_data) / sizeof(_data[0]); ++i)
{
xpath_variable* chain = _data[i];
_data[i] = rhs._data[i];
rhs._data[i] = chain;
}
}
PUGI__FN xpath_variable* xpath_variable_set::_find(const char_t* name) const
{
const size_t hash_size = sizeof(_data) / sizeof(_data[0]);
size_t hash = impl::hash_string(name) % hash_size;
@ -11290,6 +11351,33 @@ namespace pugi
return 0;
}
PUGI__FN bool xpath_variable_set::_clone(xpath_variable* var, xpath_variable** out_result)
{
xpath_variable* last = 0;
while (var)
{
// allocate storage for new variable
xpath_variable* nvar = impl::new_xpath_variable(var->_type, var->name());
if (!nvar) return false;
// link the variable to the result immediately to handle failures gracefully
if (last)
last->_next = nvar;
else
*out_result = nvar;
last = nvar;
// copy the value; this can fail due to out-of-memory conditions
if (!impl::copy_xpath_variable(nvar, var)) return false;
var = var->_next;
}
return true;
}
PUGI__FN xpath_variable* xpath_variable_set::add(const char_t* name, xpath_value_type type)
{
const size_t hash_size = sizeof(_data) / sizeof(_data[0]);
@ -11339,12 +11427,12 @@ namespace pugi
PUGI__FN xpath_variable* xpath_variable_set::get(const char_t* name)
{
return find(name);
return _find(name);
}
PUGI__FN const xpath_variable* xpath_variable_set::get(const char_t* name) const
{
return find(name);
return _find(name);
}
PUGI__FN xpath_query::xpath_query(const char_t* query, xpath_variable_set* variables): _impl(0)

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@ -1075,17 +1075,22 @@ namespace pugi
private:
xpath_variable* _data[64];
// Non-copyable semantics
xpath_variable_set(const xpath_variable_set&);
xpath_variable_set& operator=(const xpath_variable_set&);
void _assign(const xpath_variable_set& rhs);
void _swap(xpath_variable_set& rhs);
xpath_variable* find(const char_t* name) const;
xpath_variable* _find(const char_t* name) const;
static bool _clone(xpath_variable* var, xpath_variable** out_result);
public:
// Default constructor/destructor
xpath_variable_set();
~xpath_variable_set();
// Copy constructor/assignment operator
xpath_variable_set(const xpath_variable_set& rhs);
xpath_variable_set& operator=(const xpath_variable_set& rhs);
// Add a new variable or get the existing one, if the types match
xpath_variable* add(const char_t* name, xpath_value_type type);

View File

@ -413,4 +413,64 @@ TEST_XML(xpath_variables_count_sum, "<node><c1>12</c1><c2>23</c2><c3>34</c3></no
CHECK_XPATH_NUMBER_VAR(xml_node(), STR("sum($c12) * count($c) - sum($c3)"), &set, 71);
}
TEST_XML(xpath_variables_copy, "<node />")
{
xpath_variable_set set1;
set1.set(STR("a"), true);
set1.set(STR("b"), 2.0);
set1.set(STR("c"), STR("string"));
set1.set(STR("d"), doc.select_nodes(STR("//*")));
CHECK_XPATH_STRING_VAR(xml_node(), STR("substring($c, count($d[$a]) + $b)"), &set1, STR("ring"));
xpath_variable_set set2 = set1;
CHECK_XPATH_STRING_VAR(xml_node(), STR("substring($c, count($d[$a]) + $b)"), &set2, STR("ring"));
xpath_variable_set set3;
CHECK(!set3.get(STR("a")));
set3 = set1;
CHECK_XPATH_STRING_VAR(xml_node(), STR("substring($c, count($d[$a]) + $b)"), &set2, STR("ring"));
set3 = set3;
CHECK_XPATH_STRING_VAR(xml_node(), STR("substring($c, count($d[$a]) + $b)"), &set2, STR("ring"));
set3 = xpath_variable_set();
CHECK(!set3.get(STR("a")));
}
TEST_XML(xpath_variables_copy_out_of_memory, "<node />")
{
xpath_variable_set set1;
set1.set(STR("a"), true);
set1.set(STR("b"), 2.0);
set1.set(STR("c"), STR("string"));
set1.set(STR("d"), doc.select_nodes(STR("//*")));
xpath_variable_set set2 = set1;
test_runner::_memory_fail_threshold = 32768 + 75 * sizeof(void*);
CHECK_ALLOC_FAIL(xpath_variable_set set3 = set1);
xpath_variable_set set4;
CHECK_ALLOC_FAIL(set4 = set1);
CHECK(!set4.get(STR("a")) && !set4.get(STR("b")) && !set4.get(STR("c")) && !set4.get(STR("d")));
CHECK_ALLOC_FAIL(set2 = set1);
CHECK(set2.get(STR("a")) && set2.get(STR("b")) && set2.get(STR("c")) && set2.get(STR("d")));
CHECK(set2.get(STR("a"))->get_boolean() == true);
CHECK(set2.get(STR("b"))->get_number() == 2.0);
CHECK_STRING(set2.get(STR("c"))->get_string(), STR("string"));
CHECK(set2.get(STR("d"))->get_node_set().size() == 1);
}
#endif