Louis Dionne 1754774369 [libc++] Fix error flags and exceptions propagated from input stream operations
Summary:
Before this patch, we would only ever throw an exception if the badbit
was set on the stream. The Standard is currently very unclear on how
exceptions should be propagated and what error flags should be set by
the input stream operations. This commit changes libc++ to behave under
a different (but valid) interpretation of the Standard. This interpretation
of the Standard matches what other implementations are doing.

I will submit a paper in San Diego to clarify the Standard such that the
interpretation used in this commit (and other implementations) is the only
possible one.

PR21586
PR15949
rdar://problem/15347558

Reviewers: mclow.lists, EricWF

Subscribers: christof, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D49863

llvm-svn: 357531
2019-04-02 21:43:07 +00:00

163 lines
4.2 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <string>
// template<class charT, class traits, class Allocator>
// basic_istream<charT,traits>&
// getline(basic_istream<charT,traits>& is,
// basic_string<charT,traits,Allocator>& str);
#include <string>
#include <sstream>
#include <cassert>
#include "min_allocator.h"
#include "test_macros.h"
int main(int, char**)
{
{
std::istringstream in(" abc\n def\n ghij");
std::string s("initial text");
getline(in, s);
assert(in.good());
assert(s == " abc");
getline(in, s);
assert(in.good());
assert(s == " def");
getline(in, s);
assert(in.eof());
assert(s == " ghij");
}
{
std::wistringstream in(L" abc\n def\n ghij");
std::wstring s(L"initial text");
getline(in, s);
assert(in.good());
assert(s == L" abc");
getline(in, s);
assert(in.good());
assert(s == L" def");
getline(in, s);
assert(in.eof());
assert(s == L" ghij");
}
#if TEST_STD_VER >= 11
{
typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
std::istringstream in(" abc\n def\n ghij");
S s("initial text");
getline(in, s);
assert(in.good());
assert(s == " abc");
getline(in, s);
assert(in.good());
assert(s == " def");
getline(in, s);
assert(in.eof());
assert(s == " ghij");
}
{
typedef std::basic_string<wchar_t, std::char_traits<wchar_t>, min_allocator<wchar_t>> S;
std::wistringstream in(L" abc\n def\n ghij");
S s(L"initial text");
getline(in, s);
assert(in.good());
assert(s == L" abc");
getline(in, s);
assert(in.good());
assert(s == L" def");
getline(in, s);
assert(in.eof());
assert(s == L" ghij");
}
#endif
#ifndef TEST_HAS_NO_EXCEPTIONS
{
std::basic_stringbuf<char> sb("hello");
std::basic_istream<char> is(&sb);
is.exceptions(std::ios_base::eofbit);
std::basic_string<char> s;
bool threw = false;
try {
std::getline(is, s);
} catch (std::ios::failure const&) {
threw = true;
}
assert(!is.bad());
assert(!is.fail());
assert( is.eof());
assert(threw);
assert(s == "hello");
}
{
std::basic_stringbuf<wchar_t> sb(L"hello");
std::basic_istream<wchar_t> is(&sb);
is.exceptions(std::ios_base::eofbit);
std::basic_string<wchar_t> s;
bool threw = false;
try {
std::getline(is, s);
} catch (std::ios::failure const&) {
threw = true;
}
assert(!is.bad());
assert(!is.fail());
assert( is.eof());
assert(threw);
assert(s == L"hello");
}
{
std::basic_stringbuf<char> sb;
std::basic_istream<char> is(&sb);
is.exceptions(std::ios_base::failbit);
std::basic_string<char> s;
bool threw = false;
try {
std::getline(is, s);
} catch (std::ios::failure const&) {
threw = true;
}
assert(!is.bad());
assert( is.fail());
assert( is.eof());
assert(threw);
assert(s == "");
}
{
std::basic_stringbuf<wchar_t> sb;
std::basic_istream<wchar_t> is(&sb);
is.exceptions(std::ios_base::failbit);
std::basic_string<wchar_t> s;
bool threw = false;
try {
std::getline(is, s);
} catch (std::ios::failure const&) {
threw = true;
}
assert(!is.bad());
assert( is.fail());
assert( is.eof());
assert(threw);
assert(s == L"");
}
#endif // TEST_HAS_NO_EXCEPTIONS
return 0;
}