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libstdc++: Add nodiscard attribute to filesystem operations 

Some of these are not truly "pure" because they access the file system,
e.g. exists and file_size, but they do not modify anything and are only
useful for the return value.

If you really want to use one of those functions just to check whether
an error is reported (either via an exception or an error_code&
argument) you can still do so, but you need to cast the discarded result
to void.  Several tests need such a change, because they were indeed
only calling the functions to check for expected errors.

libstdc++-v3/ChangeLog:

	* include/bits/fs_ops.h: Add nodiscard to all pure functions.
	* include/experimental/bits/fs_ops.h: Likewise.
	* testsuite/27_io/filesystem/operations/all.cc: Do not discard
	results of absolute and canonical.
	* testsuite/27_io/filesystem/operations/absolute.cc: Cast
	discarded result to void.
	* testsuite/27_io/filesystem/operations/canonical.cc: Likewise.
	* testsuite/27_io/filesystem/operations/exists.cc: Likewise.
	* testsuite/27_io/filesystem/operations/is_empty.cc: Likewise.
	* testsuite/27_io/filesystem/operations/read_symlink.cc:
	Likewise.
	* testsuite/27_io/filesystem/operations/status.cc: Likewise.
	* testsuite/27_io/filesystem/operations/symlink_status.cc:
	Likewise.
	* testsuite/27_io/filesystem/operations/temp_directory_path.cc:
	Likewise.
	* testsuite/experimental/filesystem/operations/canonical.cc:
	Likewise.
	* testsuite/experimental/filesystem/operations/exists.cc:
	Likewise.
	* testsuite/experimental/filesystem/operations/is_empty.cc:
	Likewise.
	* testsuite/experimental/filesystem/operations/read_symlink.cc:
	Likewise.
	* testsuite/experimental/filesystem/operations/temp_directory_path.cc:
	Likewise.

(cherry picked from commit f7a148304a)
This commit is contained in:
Jonathan Wakely 2022-07-01 11:40:29 +01:00
parent e562236851
commit cff25d209b
16 changed files with 174 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
libstdc++-v3/include/bits/fs_ops.h
View File

@ -44,10 +44,16 @@ namespace filesystem
* @{
*/
[[nodiscard]]
path absolute(const path& __p);
[[nodiscard]]
path absolute(const path& __p, error_code& __ec);
[[nodiscard]]
path canonical(const path& __p);
[[nodiscard]]
path canonical(const path& __p, error_code& __ec);
inline void
@ -100,25 +106,34 @@ namespace filesystem
void create_symlink(const path& __to, const path& __new_symlink,
error_code& __ec) noexcept;
[[nodiscard]]
path current_path();
[[nodiscard]]
path current_path(error_code& __ec);
void current_path(const path& __p);
void current_path(const path& __p, error_code& __ec) noexcept;
[[nodiscard]]
bool
equivalent(const path& __p1, const path& __p2);
[[nodiscard]]
bool
equivalent(const path& __p1, const path& __p2, error_code& __ec) noexcept;
[[nodiscard]]
inline bool
exists(file_status __s) noexcept
{ return status_known(__s) && __s.type() != file_type::not_found; }
[[nodiscard]]
inline bool
exists(const path& __p)
{ return exists(status(__p)); }
[[nodiscard]]
inline bool
exists(const path& __p, error_code& __ec) noexcept
{
@ -131,63 +146,85 @@ namespace filesystem
return false;
}
[[nodiscard]]
uintmax_t file_size(const path& __p);
[[nodiscard]]
uintmax_t file_size(const path& __p, error_code& __ec) noexcept;
[[nodiscard]]
uintmax_t hard_link_count(const path& __p);
[[nodiscard]]
uintmax_t hard_link_count(const path& __p, error_code& __ec) noexcept;
[[nodiscard]]
inline bool
is_block_file(file_status __s) noexcept
{ return __s.type() == file_type::block; }
[[nodiscard]]
inline bool
is_block_file(const path& __p)
{ return is_block_file(status(__p)); }
[[nodiscard]]
inline bool
is_block_file(const path& __p, error_code& __ec) noexcept
{ return is_block_file(status(__p, __ec)); }
[[nodiscard]]
inline bool
is_character_file(file_status __s) noexcept
{ return __s.type() == file_type::character; }
[[nodiscard]]
inline bool
is_character_file(const path& __p)
{ return is_character_file(status(__p)); }
[[nodiscard]]
inline bool
is_character_file(const path& __p, error_code& __ec) noexcept
{ return is_character_file(status(__p, __ec)); }
[[nodiscard]]
inline bool
is_directory(file_status __s) noexcept
{ return __s.type() == file_type::directory; }
[[nodiscard]]
inline bool
is_directory(const path& __p)
{ return is_directory(status(__p)); }
[[nodiscard]]
inline bool
is_directory(const path& __p, error_code& __ec) noexcept
{ return is_directory(status(__p, __ec)); }
[[nodiscard]]
bool is_empty(const path& __p);
[[nodiscard]]
bool is_empty(const path& __p, error_code& __ec);
[[nodiscard]]
inline bool
is_fifo(file_status __s) noexcept
{ return __s.type() == file_type::fifo; }
[[nodiscard]]
inline bool
is_fifo(const path& __p)
{ return is_fifo(status(__p)); }
[[nodiscard]]
inline bool
is_fifo(const path& __p, error_code& __ec) noexcept
{ return is_fifo(status(__p, __ec)); }
[[nodiscard]]
inline bool
is_other(file_status __s) noexcept
{
@ -195,52 +232,67 @@ namespace filesystem
&& !is_symlink(__s);
}
[[nodiscard]]
inline bool
is_other(const path& __p)
{ return is_other(status(__p)); }
[[nodiscard]]
inline bool
is_other(const path& __p, error_code& __ec) noexcept
{ return is_other(status(__p, __ec)); }
[[nodiscard]]
inline bool
is_regular_file(file_status __s) noexcept
{ return __s.type() == file_type::regular; }
[[nodiscard]]
inline bool
is_regular_file(const path& __p)
{ return is_regular_file(status(__p)); }
[[nodiscard]]
inline bool
is_regular_file(const path& __p, error_code& __ec) noexcept
{ return is_regular_file(status(__p, __ec)); }
[[nodiscard]]
inline bool
is_socket(file_status __s) noexcept
{ return __s.type() == file_type::socket; }
[[nodiscard]]
inline bool
is_socket(const path& __p)
{ return is_socket(status(__p)); }
[[nodiscard]]
inline bool
is_socket(const path& __p, error_code& __ec) noexcept
{ return is_socket(status(__p, __ec)); }
[[nodiscard]]
inline bool
is_symlink(file_status __s) noexcept
{ return __s.type() == file_type::symlink; }
[[nodiscard]]
inline bool
is_symlink(const path& __p)
{ return is_symlink(symlink_status(__p)); }
[[nodiscard]]
inline bool
is_symlink(const path& __p, error_code& __ec) noexcept
{ return is_symlink(symlink_status(__p, __ec)); }
[[nodiscard]]
file_time_type last_write_time(const path& __p);
[[nodiscard]]
file_time_type last_write_time(const path& __p, error_code& __ec) noexcept;
void last_write_time(const path& __p, file_time_type __new_time);
void last_write_time(const path& __p, file_time_type __new_time,
error_code& __ec) noexcept;
@ -257,19 +309,30 @@ namespace filesystem
permissions(const path& __p, perms __prms, perm_options __opts,
error_code& __ec) noexcept;
[[nodiscard]]
inline path proximate(const path& __p, error_code& __ec)
{ return proximate(__p, current_path(), __ec); }
[[nodiscard]]
path proximate(const path& __p, const path& __base = current_path());
[[nodiscard]]
path proximate(const path& __p, const path& __base, error_code& __ec);
[[nodiscard]]
path read_symlink(const path& __p);
[[nodiscard]]
path read_symlink(const path& __p, error_code& __ec);
[[nodiscard]]
inline path relative(const path& __p, error_code& __ec)
{ return relative(__p, current_path(), __ec); }
[[nodiscard]]
path relative(const path& __p, const path& __base = current_path());
[[nodiscard]]
path relative(const path& __p, const path& __base, error_code& __ec);
bool remove(const path& __p);
@ -284,22 +347,38 @@ namespace filesystem
void resize_file(const path& __p, uintmax_t __size);
void resize_file(const path& __p, uintmax_t __size, error_code& __ec) noexcept;
[[nodiscard]]
space_info space(const path& __p);
[[nodiscard]]
space_info space(const path& __p, error_code& __ec) noexcept;
[[nodiscard]]
file_status status(const path& __p);
[[nodiscard]]
file_status status(const path& __p, error_code& __ec) noexcept;
[[nodiscard]]
inline bool status_known(file_status __s) noexcept
{ return __s.type() != file_type::none; }
[[nodiscard]]
file_status symlink_status(const path& __p);
[[nodiscard]]
file_status symlink_status(const path& __p, error_code& __ec) noexcept;
[[nodiscard]]
path temp_directory_path();
[[nodiscard]]
path temp_directory_path(error_code& __ec);
[[nodiscard]]
path weakly_canonical(const path& __p);
[[nodiscard]]
path weakly_canonical(const path& __p, error_code& __ec);
/// @} group filesystem

71
libstdc++-v3/include/experimental/bits/fs_ops.h
View File

@ -51,10 +51,16 @@ inline namespace v1
* @{
*/
[[__nodiscard__]]
path absolute(const path& __p, const path& __base = current_path());
[[__nodiscard__]]
path canonical(const path& __p, const path& __base = current_path());
[[__nodiscard__]]
path canonical(const path& __p, error_code& __ec);
[[__nodiscard__]]
path canonical(const path& __p, const path& __base, error_code& __ec);
inline void
@ -66,6 +72,7 @@ inline namespace v1
{ copy(__from, __to, copy_options::none, __ec); }
void copy(const path& __from, const path& __to, copy_options __options);
void copy(const path& __from, const path& __to, copy_options __options,
error_code& __ec) noexcept;
@ -107,25 +114,34 @@ inline namespace v1
void create_symlink(const path& __to, const path& __new_symlink,
error_code& __ec) noexcept;
[[__nodiscard__]]
path current_path();
[[__nodiscard__]]
path current_path(error_code& __ec);
void current_path(const path& __p);
void current_path(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
bool
equivalent(const path& __p1, const path& __p2);
[[__nodiscard__]]
bool
equivalent(const path& __p1, const path& __p2, error_code& __ec) noexcept;
[[__nodiscard__]]
inline bool
exists(file_status __s) noexcept
{ return status_known(__s) && __s.type() != file_type::not_found; }
[[__nodiscard__]]
inline bool
exists(const path& __p)
{ return exists(status(__p)); }
[[__nodiscard__]]
inline bool
exists(const path& __p, error_code& __ec) noexcept
{
@ -138,63 +154,84 @@ inline namespace v1
return false;
}
[[__nodiscard__]]
uintmax_t file_size(const path& __p);
[[__nodiscard__]]
uintmax_t file_size(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
uintmax_t hard_link_count(const path& __p);
[[__nodiscard__]]
uintmax_t hard_link_count(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
inline bool
is_block_file(file_status __s) noexcept
{ return __s.type() == file_type::block; }
[[__nodiscard__]]
inline bool
is_block_file(const path& __p)
{ return is_block_file(status(__p)); }
[[__nodiscard__]]
inline bool
is_block_file(const path& __p, error_code& __ec) noexcept
{ return is_block_file(status(__p, __ec)); }
[[__nodiscard__]]
inline bool
is_character_file(file_status __s) noexcept
{ return __s.type() == file_type::character; }
[[__nodiscard__]]
inline bool
is_character_file(const path& __p)
{ return is_character_file(status(__p)); }
[[__nodiscard__]]
inline bool
is_character_file(const path& __p, error_code& __ec) noexcept
{ return is_character_file(status(__p, __ec)); }
[[__nodiscard__]]
inline bool
is_directory(file_status __s) noexcept
{ return __s.type() == file_type::directory; }
[[__nodiscard__]]
inline bool
is_directory(const path& __p)
{ return is_directory(status(__p)); }
[[__nodiscard__]]
inline bool
is_directory(const path& __p, error_code& __ec) noexcept
{ return is_directory(status(__p, __ec)); }
[[__nodiscard__]]
bool is_empty(const path& __p);
[[__nodiscard__]]
bool is_empty(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
inline bool
is_fifo(file_status __s) noexcept
{ return __s.type() == file_type::fifo; }
[[__nodiscard__]]
inline bool
is_fifo(const path& __p)
{ return is_fifo(status(__p)); }
[[__nodiscard__]]
inline bool
is_fifo(const path& __p, error_code& __ec) noexcept
{ return is_fifo(status(__p, __ec)); }
[[__nodiscard__]]
inline bool
is_other(file_status __s) noexcept
{
@ -202,52 +239,67 @@ inline namespace v1
&& !is_symlink(__s);
}
[[__nodiscard__]]
inline bool
is_other(const path& __p)
{ return is_other(status(__p)); }
[[__nodiscard__]]
inline bool
is_other(const path& __p, error_code& __ec) noexcept
{ return is_other(status(__p, __ec)); }
[[__nodiscard__]]
inline bool
is_regular_file(file_status __s) noexcept
{ return __s.type() == file_type::regular; }
[[__nodiscard__]]
inline bool
is_regular_file(const path& __p)
{ return is_regular_file(status(__p)); }
[[__nodiscard__]]
inline bool
is_regular_file(const path& __p, error_code& __ec) noexcept
{ return is_regular_file(status(__p, __ec)); }
[[__nodiscard__]]
inline bool
is_socket(file_status __s) noexcept
{ return __s.type() == file_type::socket; }
[[__nodiscard__]]
inline bool
is_socket(const path& __p)
{ return is_socket(status(__p)); }
[[__nodiscard__]]
inline bool
is_socket(const path& __p, error_code& __ec) noexcept
{ return is_socket(status(__p, __ec)); }
[[__nodiscard__]]
inline bool
is_symlink(file_status __s) noexcept
{ return __s.type() == file_type::symlink; }
[[__nodiscard__]]
inline bool
is_symlink(const path& __p)
{ return is_symlink(symlink_status(__p)); }
[[__nodiscard__]]
inline bool
is_symlink(const path& __p, error_code& __ec) noexcept
{ return is_symlink(symlink_status(__p, __ec)); }
[[__nodiscard__]]
file_time_type last_write_time(const path& __p);
[[__nodiscard__]]
file_time_type last_write_time(const path& __p, error_code& __ec) noexcept;
void last_write_time(const path& __p, file_time_type __new_time);
void last_write_time(const path& __p, file_time_type __new_time,
error_code& __ec) noexcept;
@ -255,7 +307,10 @@ inline namespace v1
void permissions(const path& __p, perms __prms);
void permissions(const path& __p, perms __prms, error_code& __ec) noexcept;
[[__nodiscard__]]
path read_symlink(const path& __p);
[[__nodiscard__]]
path read_symlink(const path& __p, error_code& __ec);
bool remove(const path& __p);
@ -270,22 +325,38 @@ inline namespace v1
void resize_file(const path& __p, uintmax_t __size);
void resize_file(const path& __p, uintmax_t __size, error_code& __ec) noexcept;
[[__nodiscard__]]
space_info space(const path& __p);
[[__nodiscard__]]
space_info space(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
file_status status(const path& __p);
[[__nodiscard__]]
file_status status(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
inline bool status_known(file_status __s) noexcept
{ return __s.type() != file_type::none; }
[[__nodiscard__]]
file_status symlink_status(const path& __p);
[[__nodiscard__]]
file_status symlink_status(const path& __p, error_code& __ec) noexcept;
[[__nodiscard__]]
path system_complete(const path& __p);
[[__nodiscard__]]
path system_complete(const path& __p, error_code& __ec);
[[__nodiscard__]]
path temp_directory_path();
[[__nodiscard__]]
path temp_directory_path(error_code& __ec);
/// @} group filesystem-ts

2
libstdc++-v3/testsuite/27_io/filesystem/operations/absolute.cc
View File

@ -84,7 +84,7 @@ test03()
VERIFY( eabs.empty() );
try {
absolute(path{});
(void) absolute(path{});
VERIFY( false );
} catch (const std::filesystem::filesystem_error& e) {
VERIFY( e.code() == std::errc::invalid_argument );

8
libstdc++-v3/testsuite/27_io/filesystem/operations/all.cc
View File

@ -42,11 +42,11 @@ main()
bool b [[maybe_unused]];
std::uintmax_t size;
std::filesystem::absolute(p);
std::filesystem::absolute(p, ec);
p2 = std::filesystem::absolute(p);
p2 = std::filesystem::absolute(p, ec);
std::filesystem::canonical(p);
std::filesystem::canonical(p, ec);
p2 = std::filesystem::canonical(p);
p2 = std::filesystem::canonical(p, ec);
std::filesystem::copy(p, p);
std::filesystem::copy(p, p, ec);

4
libstdc++-v3/testsuite/27_io/filesystem/operations/canonical.cc
View File

@ -31,7 +31,7 @@ test01()
const std::error_code bad_ec = make_error_code(std::errc::invalid_argument);
std::error_code ec;
auto p = __gnu_test::nonexistent_path();
canonical( p, ec );
(void) canonical( p, ec );
VERIFY( ec );
create_directory(p);
@ -90,7 +90,7 @@ test02()
#if __cpp_exceptions
fs::path e1, e2;
try {
canonical(p);
(void) canonical(p);
} catch (const fs::filesystem_error& e) {
e1 = e.path1();
e2 = e.path2();

2
libstdc++-v3/testsuite/27_io/filesystem/operations/exists.cc
View File

@ -95,7 +95,7 @@ test04()
ec.clear();
try
{
exists(unr);
(void) exists(unr);
}
catch(const std::filesystem::filesystem_error& ex)
{

4
libstdc++-v3/testsuite/27_io/filesystem/operations/is_empty.cc
View File

@ -40,7 +40,7 @@ test01()
VERIFY( !result );
try {
fs::is_empty(p);
(void) fs::is_empty(p);
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}
@ -51,7 +51,7 @@ test01()
VERIFY( !result );
try {
fs::is_empty(p/"f");
(void) fs::is_empty(p/"f");
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}

2
libstdc++-v3/testsuite/27_io/filesystem/operations/read_symlink.cc
View File

@ -31,7 +31,7 @@ test01()
auto p = __gnu_test::nonexistent_path();
std::error_code ec;
read_symlink(p, ec);
(void) read_symlink(p, ec);
VERIFY( ec );
fs::path tgt = ".";

2
libstdc++-v3/testsuite/27_io/filesystem/operations/status.cc
View File

@ -74,7 +74,7 @@ test03()
std::error_code ec2;
fs::path p, p2;
try {
fs::symlink_status(f.path);
(void) fs::symlink_status(f.path);
} catch (const fs::filesystem_error& e) {
caught = true;
p = e.path1();

2
libstdc++-v3/testsuite/27_io/filesystem/operations/symlink_status.cc
View File

@ -94,7 +94,7 @@ test03()
std::error_code ec2;
fs::path p, p2;
try {
fs::symlink_status(f.path);
(void) fs::symlink_status(f.path);
} catch (const fs::filesystem_error& e) {
caught = true;
p = e.path1();

4
libstdc++-v3/testsuite/27_io/filesystem/operations/temp_directory_path.cc
View File

@ -117,7 +117,7 @@ test03()
std::error_code ec2;
try {
fs::temp_directory_path();
(void) fs::temp_directory_path();
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}
@ -141,7 +141,7 @@ test04()
std::error_code ec2;
try {
fs::temp_directory_path();
(void) fs::temp_directory_path();
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}

6
libstdc++-v3/testsuite/experimental/filesystem/operations/canonical.cc
View File

@ -30,11 +30,11 @@ test01()
{
std::error_code ec;
auto p = __gnu_test::nonexistent_path();
canonical( p, ec );
(void) canonical( p, ec );
VERIFY( ec );
p = fs::current_path();
canonical( p, ec );
(void) canonical( p, ec );
VERIFY( !ec );
const auto root = fs::absolute("/");
@ -67,7 +67,7 @@ test02()
fs::path p = "rel", base = __gnu_test::nonexistent_path();
fs::path e1, e2;
try {
canonical(p, base);
(void) canonical(p, base);
} catch (const fs::filesystem_error& e) {
e1 = e.path1();
e2 = e.path2();

2
libstdc++-v3/testsuite/experimental/filesystem/operations/exists.cc
View File

@ -89,7 +89,7 @@ test04()
ec.clear();
try
{
exists(unr);
(void) exists(unr);
}
catch(const std::experimental::filesystem::filesystem_error& ex)
{

4
libstdc++-v3/testsuite/experimental/filesystem/operations/is_empty.cc
View File

@ -41,7 +41,7 @@ test01()
VERIFY( !result );
try {
fs::is_empty(p);
(void) fs::is_empty(p);
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}
@ -52,7 +52,7 @@ test01()
VERIFY( !result );
try {
fs::is_empty(p/"f");
(void) fs::is_empty(p/"f");
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}

2
libstdc++-v3/testsuite/experimental/filesystem/operations/read_symlink.cc
View File

@ -32,7 +32,7 @@ test01()
auto p = __gnu_test::nonexistent_path();
std::error_code ec;
read_symlink(p, ec);
(void) read_symlink(p, ec);
VERIFY( ec );
fs::path tgt = ".";

4
libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
View File

@ -118,7 +118,7 @@ test03()
std::error_code ec2;
try {
fs::temp_directory_path();
(void) fs::temp_directory_path();
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}
@ -142,7 +142,7 @@ test04()
std::error_code ec2;
try {
fs::temp_directory_path();
(void) fs::temp_directory_path();
} catch (const fs::filesystem_error& e) {
ec2 = e.code();
}