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[libc++] Add internal checks for some basic_streambuf invariants #144602

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[libc++] Add internal checks for some basic_streambuf invariants #144602

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40 changes: 40 additions & 0 deletions libcxx/include/streambuf
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Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,7 @@ protected:
# include <__locale>
# include <__type_traits/is_same.h>
# include <__utility/is_valid_range.h>
# include <__utility/scope_guard.h>
# include <climits>
# include <ios>
# include <iosfwd>
Expand Down Expand Up @@ -178,18 +179,27 @@ public:
// Get and put areas:
// 27.6.2.2.3 Get area:
inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 streamsize in_avail() {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (gptr() < egptr())
return static_cast<streamsize>(egptr() - gptr());
return showmanyc();
}

inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 int_type snextc() {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (sbumpc() == traits_type::eof())
return traits_type::eof();
return sgetc();
}

inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 int_type sbumpc() {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (gptr() == egptr())
return uflow();
int_type __c = traits_type::to_int_type(*gptr());
Expand All @@ -198,6 +208,9 @@ public:
}

inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 int_type sgetc() {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (gptr() == egptr())
return underflow();
return traits_type::to_int_type(*gptr());
Expand All @@ -207,13 +220,19 @@ public:

// 27.6.2.2.4 Putback:
inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 int_type sputbackc(char_type __c) {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (eback() == gptr() || !traits_type::eq(__c, *(gptr() - 1)))
return pbackfail(traits_type::to_int_type(__c));
this->gbump(-1);
return traits_type::to_int_type(*gptr());
}

inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 int_type sungetc() {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (eback() == gptr())
return pbackfail();
this->gbump(-1);
Expand All @@ -222,6 +241,9 @@ public:

// 27.6.2.2.5 Put area:
inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 int_type sputc(char_type __c) {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (pptr() == epptr())
return overflow(traits_type::to_int_type(__c));
*pptr() = __c;
Expand Down Expand Up @@ -317,6 +339,9 @@ protected:
virtual streamsize showmanyc() { return 0; }

virtual streamsize xsgetn(char_type* __s, streamsize __n) {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

int_type __c;
streamsize __i = 0;
while (__i < __n) {
Expand All @@ -338,6 +363,9 @@ protected:

virtual int_type underflow() { return traits_type::eof(); }
virtual int_type uflow() {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

if (underflow() == traits_type::eof())
return traits_type::eof();
int_type __c = traits_type::to_int_type(*gptr());
Expand All @@ -350,6 +378,9 @@ protected:

// 27.6.2.4.5 Put area:
virtual streamsize xsputn(const char_type* __s, streamsize __n) {
__check_invariants();
auto __guard = std::__make_scope_guard([this] { this->__check_invariants(); });

streamsize __i = 0;
while (__i < __n) {
if (pptr() >= epptr()) {
Expand All @@ -370,6 +401,15 @@ protected:

virtual int_type overflow(int_type = traits_type::eof()) { return traits_type::eof(); }

// This function checks some invariants of the class (it isn't exhaustive).
_LIBCPP_HIDE_FROM_ABI void __check_invariants() const {
_LIBCPP_ASSERT_INTERNAL(pbase() <= pptr(), "this is an invariant of the class");
_LIBCPP_ASSERT_INTERNAL(pptr() <= epptr(), "this is an invariant of the class");

_LIBCPP_ASSERT_INTERNAL(eback() <= gptr(), "this is an invariant of the class");
_LIBCPP_ASSERT_INTERNAL(gptr() <= egptr(), "this is an invariant of the class");
}

private:
locale __loc_;
char_type* __binp_ = nullptr;
Expand Down
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