mirrors/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2025-02-24 07:28:02 +01:00
Code Issues Projects Releases Wiki Activity

util: Support dynamic width & precision in ConstevalFormatString

Browse source 
This is needed in the next commit to add compile-time checking to strprintf
calls, because bitcoin-cli.cpp uses dynamic width in many format strings.

This change is easiest to review ignoring whitespace.

Co-authored-by: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>
Co-authored-by: Hodlinator <172445034+hodlinator@users.noreply.github.com>
Co-authored-by: l0rinc <pap.lorinc@gmail.com>
This commit is contained in:
Ryan Ofsky 2024-10-28 19:11:16 -04:00
parent da10e0bab4
commit 184f34f2d0
2 changed files with 82 additions and 40 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

44
src/test/util_string_tests.cpp
View file

@ -20,7 +20,7 @@ inline void PassFmt(util::ConstevalFormatString<NumArgs> fmt)
decltype(fmt)::Detail_CheckNumFormatSpecifiers(fmt.fmt);
}
template <unsigned WrongNumArgs>
inline void FailFmtWithError(std::string_view wrong_fmt, std::string_view error)
inline void FailFmtWithError(const char* wrong_fmt, std::string_view error)
{
BOOST_CHECK_EXCEPTION(util::ConstevalFormatString<WrongNumArgs>::Detail_CheckNumFormatSpecifiers(wrong_fmt), const char*, HasReason(error));
}
@ -44,6 +44,8 @@ BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)
PassFmt<1>("%+2s");
PassFmt<1>("%.6i");
PassFmt<1>("%5.2f");
PassFmt<1>("%5.f");
PassFmt<1>("%.f");
PassFmt<1>("%#x");
PassFmt<1>("%1$5i");
PassFmt<1>("%1$-5i");
@ -54,15 +56,27 @@ BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)
PassFmt<1>("%_");
PassFmt<1>("%\n");
// The `*` specifier behavior is unsupported and can lead to runtime
// errors when used in a ConstevalFormatString. Please refer to the
// note in the ConstevalFormatString docs.
PassFmt<1>("%*c");
PassFmt<2>("%2$*3$d");
PassFmt<1>("%.*f");
PassFmt<2>("%*c");
PassFmt<2>("%+*c");
PassFmt<2>("%.*f");
PassFmt<3>("%*.*f");
PassFmt<3>("%2$*3$d");
PassFmt<3>("%2$*3$.9d");
PassFmt<3>("%2$.*3$d");
PassFmt<3>("%2$9.*3$d");
PassFmt<3>("%2$+9.*3$d");
PassFmt<4>("%3$*2$.*4$f");
// Make sure multiple flag characters "- 0+" are accepted
PassFmt<3>("'%- 0+*.*f'");
PassFmt<3>("'%1$- 0+*3$.*2$f'");
auto err_mix{"Format specifiers must be all positional or all non-positional!"};
FailFmtWithError<1>("%s%1$s", err_mix);
FailFmtWithError<2>("%2$*d", err_mix);
FailFmtWithError<2>("%*2$d", err_mix);
FailFmtWithError<2>("%.*3$d", err_mix);
FailFmtWithError<2>("%2$.*d", err_mix);
auto err_num{"Format specifier count must match the argument count!"};
FailFmtWithError<1>("", err_num);
@ -70,16 +84,32 @@ BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)
FailFmtWithError<2>("%s", err_num);
FailFmtWithError<0>("%1$s", err_num);
FailFmtWithError<2>("%1$s", err_num);
FailFmtWithError<1>("%*c", err_num);
auto err_0_pos{"Positional format specifier must have position of at least 1"};
FailFmtWithError<1>("%$s", err_0_pos);
FailFmtWithError<1>("%$", err_0_pos);
FailFmtWithError<0>("%0$", err_0_pos);
FailFmtWithError<0>("%0$s", err_0_pos);
FailFmtWithError<2>("%2$*$d", err_0_pos);
FailFmtWithError<2>("%2$*0$d", err_0_pos);
FailFmtWithError<3>("%3$*2$.*$f", err_0_pos);
FailFmtWithError<3>("%3$*2$.*0$f", err_0_pos);
auto err_term{"Format specifier incorrectly terminated by end of string"};
FailFmtWithError<1>("%", err_term);
FailFmtWithError<1>("%9", err_term);
FailFmtWithError<1>("%9.", err_term);
FailFmtWithError<1>("%9.9", err_term);
FailFmtWithError<1>("%*", err_term);
FailFmtWithError<1>("%+*", err_term);
FailFmtWithError<1>("%.*", err_term);
FailFmtWithError<1>("%9.*", err_term);
FailFmtWithError<1>("%1$", err_term);
FailFmtWithError<1>("%1$9", err_term);
FailFmtWithError<2>("%1$*2$", err_term);
FailFmtWithError<2>("%1$.*2$", err_term);
FailFmtWithError<2>("%1$9.*2$", err_term);
}
BOOST_AUTO_TEST_SUITE_END()

78
src/util/string.h
View file

@ -25,53 +25,65 @@ namespace util {
* strings, to reduce the likelihood of tinyformat throwing exceptions at
* run-time. Validation is partial to try and prevent the most common errors
* while avoiding re-implementing the entire parsing logic.
*
* @note Counting of `*` dynamic width and precision fields (such as `%*c`,
* `%2$*3$d`, `%.*f`) is not implemented to minimize code complexity as long as
* they are not used in the codebase. Usage of these fields is not counted and
* can lead to run-time exceptions. Code wanting to use the `*` specifier can
* side-step this struct and call tinyformat directly.
*/
template <unsigned num_params>
struct ConstevalFormatString {
const char* const fmt;
consteval ConstevalFormatString(const char* str) : fmt{str} { Detail_CheckNumFormatSpecifiers(fmt); }
constexpr static void Detail_CheckNumFormatSpecifiers(std::string_view str)
constexpr static void Detail_CheckNumFormatSpecifiers(const char* str)
{
unsigned count_normal{0}; // Number of "normal" specifiers, like %s
unsigned count_pos{0}; // Max number in positional specifier, like %8$s
for (auto it{str.begin()}; it < str.end();) {
if (*it != '%') {
++it;
continue;
}
for (auto it{str}; *it != '\0'; ++it) {
if (*it != '%' || *++it == '%') continue; // Skip escaped %%
if (++it >= str.end()) throw "Format specifier incorrectly terminated by end of string";
if (*it == '%') {
// Percent escape: %%
++it;
continue;
}
auto add_arg = [&] {
unsigned maybe_num{0};
while ('0' <= *it && *it <= '9') {
maybe_num *= 10;
maybe_num += *it - '0';
++it;
}
unsigned maybe_num{0};
while ('0' <= *it && *it <= '9') {
maybe_num *= 10;
maybe_num += *it - '0';
++it;
if (*it == '$') {
++it;
// Positional specifier, like %8$s
if (maybe_num == 0) throw "Positional format specifier must have position of at least 1";
count_pos = std::max(count_pos, maybe_num);
} else {
// Non-positional specifier, like %s
++count_normal;
}
};
if (*it == '$') {
// Positional specifier, like %8$s
if (maybe_num == 0) throw "Positional format specifier must have position of at least 1";
count_pos = std::max(count_pos, maybe_num);
if (++it >= str.end()) throw "Format specifier incorrectly terminated by end of string";
} else {
// Non-positional specifier, like %s
++count_normal;
// Increase argument count and consume positional specifier, if present.
add_arg();
// Consume flags.
while (*it == '#' || *it == '0' || *it == '-' || *it == ' ' || *it == '+') ++it;
auto parse_size = [&] {
if (*it == '*') {
++it;
add_arg();
} else {
while ('0' <= *it && *it <= '9') ++it;
}
};
// Consume dynamic or static width value.
parse_size();
// Consume dynamic or static precision value.
if (*it == '.') {
++it;
parse_size();
}
// The remainder "[flags][width][.precision][length]type" of the
// specifier is not checked. Parsing continues with the next '%'.
if (*it == '\0') throw "Format specifier incorrectly terminated by end of string";
// Length and type in "[flags][width][.precision][length]type"
// is not checked. Parsing continues with the next '%'.
}
if (count_normal && count_pos) throw "Format specifiers must be all positional or all non-positional!";
unsigned count{count_normal | count_pos};