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Make error handling more convenient

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By adding some PRAY_* macros that encapsulate both the check and the returning of a null reference (UB).
Plus transient avoidance of the flood of warnings emitted by Clang when checking 'this' for NULL.
Plus explanation about the do-while(0) loop in some error macros.
This commit is contained in:
Pedro J. Estébanez 2017-05-26 21:07:39 +02:00
parent 21bf3778d5
commit e9b7640f84
8 changed files with 66 additions and 34 deletions
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6
core/dvector.h
View File

@ -311,13 +311,9 @@ void DVector<T>::push_back(const T &p_val) {
template <class T>
const T DVector<T>::operator[](int p_index) const {
if (p_index < 0 || p_index >= size()) {
T &aux = *((T *)0); //nullreturn
ERR_FAIL_COND_V(p_index < 0 || p_index >= size(), aux);
}
PRAY_BAD_INDEX(p_index, size(), T);
Read r = read();
return r[p_index];
}

44
core/error_macros.h
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@ -114,6 +114,8 @@ extern bool _err_error_exists;
#define FUNCTION_STR __FUNCTION__
#endif
// (*): See https://stackoverflow.com/questions/257418/do-while-0-what-is-it-good-for
#define ERR_FAIL_INDEX(m_index, m_size) \
do { \
if ((m_index) < 0 || (m_index) >= (m_size)) { \
@ -121,7 +123,7 @@ extern bool _err_error_exists;
return; \
} else \
_err_error_exists = false; \
} while (0);
} while (0); // (*)
/** An index has failed if m_index<0 or m_index >=m_size, the function exists.
* This function returns an error value, if returning Error, please select the most
@ -135,7 +137,20 @@ extern bool _err_error_exists;
return m_retval; \
} else \
_err_error_exists = false; \
} while (0);
} while (0); // (*)
/** Use this one if there is no sensible fallback, that is, the error is unrecoverable.
* We'll do UB by returning a null reference and pray that we wont't crash.
*/
#define PRAY_BAD_INDEX(m_index, m_size, m_type) \
do { \
if ((m_index) < 0 || (m_index) >= (m_size)) { \
_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "SEVERE: Index " _STR(m_index) " out of size (" _STR(m_size) ")."); \
m_type *n = (m_type *)0; /* two-step to avoid warning */ \
return *n; \
} else \
_err_error_exists = false; \
} while (0); // (*)
/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
* the function will exit.
@ -187,6 +202,20 @@ extern bool _err_error_exists;
_err_error_exists = false; \
}
/** Use this one if there is no sensible fallback, that is, the error is unrecoverable.
* We'll do UB by returning a null reference and pray that we wont't crash.
*/
#define PRAY_COND(m_cond, m_type) \
{ \
if (m_cond) { \
_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "SEVERE: Condition ' " _STR(m_cond) " ' is true."); \
m_type *n = (m_type *)0; /* two-step to avoid warning */ \
return *n; \
} else \
_err_error_exists = false; \
}
/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
* the loop will skip to the next iteration.
*/
@ -233,6 +262,17 @@ extern bool _err_error_exists;
return m_value; \
}
/** Use this one if there is no sensible fallback, that is, the error is unrecoverable.
* We'll do UB by returning a null reference and pray that we wont't crash.
*/
#define PRAY(m_type) \
{ \
_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "SEVERE: Method/Function Failed."); \
m_type *n = (m_type *)0; /* two-step to avoid warning */ \
return *n; \
}
/** Print an error string.
*/

3
core/hash_map.h
View File

@ -465,8 +465,7 @@ public:
if (!e) {
e = create_entry(p_key);
if (!e)
return *(TData *)NULL; /* panic! */
PRAY_COND(!e, TData);
check_hash_table(); // perform mantenience routine
}

14
core/list.h
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@ -398,10 +398,7 @@ public:
T &operator[](int p_index) {
if (p_index < 0 || p_index >= size()) {
T &aux = *((T *)0); //nullreturn
ERR_FAIL_COND_V(p_index < 0 || p_index >= size(), aux);
}
PRAY_BAD_INDEX(p_index, size(), T);
Element *I = front();
int c = 0;
@ -415,15 +412,12 @@ public:
c++;
}
ERR_FAIL_V(*((T *)0)); // bug!!
PRAY(T); // bug!!
}
const T &operator[](int p_index) const {
if (p_index < 0 || p_index >= size()) {
T &aux = *((T *)0); //nullreturn
ERR_FAIL_COND_V(p_index < 0 || p_index >= size(), aux);
}
PRAY_BAD_INDEX(p_index, size(), T);
const Element *I = front();
int c = 0;
@ -437,7 +431,7 @@ public:
c++;
}
ERR_FAIL_V(*((T *)0)); // bug!
PRAY(T); // bug!!
}
void move_to_back(Element *p_I) {

6
core/map.h
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@ -599,9 +599,9 @@ public:
const V &operator[](const K &p_key) const {
ERR_FAIL_COND_V(!_data._root, *(V *)NULL); // crash on purpose
PRAY_COND(!_data._root, V);
const Element *e = find(p_key);
ERR_FAIL_COND_V(!e, *(V *)NULL); // crash on purpose
PRAY_COND(!e, V);
return e->_value;
}
V &operator[](const K &p_key) {
@ -613,7 +613,7 @@ public:
if (!e)
e = insert(p_key, V());
ERR_FAIL_COND_V(!e, *(V *)NULL); // crash on purpose
PRAY_COND(!e, V);
return e->_value;
}

10
core/object.h
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@ -509,6 +509,12 @@ public:
void add_change_receptor(Object *p_receptor);
void remove_change_receptor(Object *p_receptor);
// TODO: ensure 'this' is never NULL since it's UB, but by now, avoid warning flood
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wundefined-bool-conversion"
#endif
template <class T>
T *cast_to() {
@ -539,6 +545,10 @@ public:
#endif
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
enum {
NOTIFICATION_POSTINITIALIZE = 0,

11
core/vector.h
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@ -133,10 +133,7 @@ public:
inline T &operator[](int p_index) {
if (p_index < 0 || p_index >= size()) {
T &aux = *((T *)0); //nullreturn
ERR_FAIL_COND_V(p_index < 0 || p_index >= size(), aux);
}
PRAY_BAD_INDEX(p_index, size(), T);
_copy_on_write(); // wants to write, so copy on write.
@ -145,10 +142,8 @@ public:
inline const T &operator[](int p_index) const {
if (p_index < 0 || p_index >= size()) {
const T &aux = *((T *)0); //nullreturn
ERR_FAIL_COND_V(p_index < 0 || p_index >= size(), aux);
}
PRAY_BAD_INDEX(p_index, size(), T);
// no cow needed, since it's reading
return _get_data()[p_index];
}

6
core/vmap.h
View File

@ -180,10 +180,8 @@ public:
inline const V &operator[](const T &p_key) const {
int pos = _find_exact(p_key);
if (pos < 0) {
const T &aux = *((T *)0); //nullreturn
ERR_FAIL_COND_V(pos < 1, aux);
}
PRAY_COND(pos < 0, V);
return _data[pos].value;
}