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AK+Userland: Extend the compiletime format string check to other functions

Thanks to @trflynn89 for the neat implicit consteval ctor trick!
This allows us to basically slap `CheckedFormatString` on any
formatting function, and have its format argument checked at compiletime.

Note that there is a validator bug where it doesn't parse inner replaced
fields like `{:~>{}}` correctly (what should be 'left align with next
argument as size' is parsed as `{:~>{` following a literal closing
brace), so the compiletime checks are disabled on these temporarily by
forcing them to be StringViews.

This commit also removes the now unused `AK::StringLiteral` type (which
was introduced for use with NTTP strings).
This commit is contained in:
AnotherTest 2021-02-22 02:37:24 +03:30 committed by Andreas Kling
parent 29c8d34be7
commit 347d741afb
6 changed files with 277 additions and 229 deletions

View file

@ -26,6 +26,8 @@
#pragma once
#include <AK/CheckedFormatString.h>
#include <AK/AllOf.h>
#include <AK/AnyOf.h>
#include <AK/Array.h>
@ -37,161 +39,6 @@
# include <stdio.h>
#endif
#ifndef DBGLN_NO_COMPILETIME_FORMAT_CHECK
// Note: Clang 12 adds support for CTAD, but still fails to build the dbgln() checks, so they're disabled altogether for now.
// See https://oss-fuzz-build-logs.storage.googleapis.com/log-79750138-f41e-4f39-8812-7c536f1d2e35.txt, for example.
# if defined(__clang__)
# define DBGLN_NO_COMPILETIME_FORMAT_CHECK
# endif
#endif
#ifndef DBGLN_NO_COMPILETIME_FORMAT_CHECK
namespace {
template<size_t N>
consteval auto extract_used_argument_index(const char (&fmt)[N], size_t specifier_start_index, size_t specifier_end_index, size_t& next_implicit_argument_index)
{
struct {
size_t index_value { 0 };
bool saw_explicit_index { false };
} state;
for (size_t i = specifier_start_index; i < specifier_end_index; ++i) {
auto c = fmt[i];
if (c > '9' || c < '0')
break;
state.index_value *= 10;
state.index_value += c - '0';
state.saw_explicit_index = true;
}
if (!state.saw_explicit_index)
return next_implicit_argument_index++;
return state.index_value;
}
// FIXME: We should rather parse these format strings at compile-time if possible.
template<size_t N>
consteval auto count_fmt_params(const char (&fmt)[N])
{
struct {
// FIXME: Switch to variable-sized storage whenever we can come up with one :)
Array<size_t, 128> used_arguments { 0 };
size_t total_used_argument_count { 0 };
size_t next_implicit_argument_index { 0 };
bool has_explicit_argument_references { false };
size_t unclosed_braces { 0 };
size_t extra_closed_braces { 0 };
Array<size_t, 4> last_format_specifier_start { 0 };
size_t total_used_last_format_specifier_start_count { 0 };
StringLiteral<128> internal_error { { 0 } };
} result;
for (size_t i = 0; i < N; ++i) {
auto ch = fmt[i];
switch (ch) {
case '{':
if (i + 1 < N && fmt[i + 1] == '{') {
++i;
continue;
}
// Note: There's no compile-time throw, so we have to abuse a compile-time string to store errors.
if (result.total_used_last_format_specifier_start_count >= result.last_format_specifier_start.size() - 1)
result.internal_error = "Format-String Checker internal error: Format specifier nested too deep";
result.last_format_specifier_start[result.total_used_last_format_specifier_start_count++] = i + 1;
++result.unclosed_braces;
break;
case '}':
if (i + 1 < N && fmt[i + 1] == '}') {
++i;
continue;
}
if (result.unclosed_braces) {
--result.unclosed_braces;
if (result.total_used_last_format_specifier_start_count == 0)
result.internal_error = "Format-String Checker internal error: Expected location information";
const auto specifier_start_index = result.last_format_specifier_start[--result.total_used_last_format_specifier_start_count];
if (result.total_used_argument_count >= result.used_arguments.size())
result.internal_error = "Format-String Checker internal error: Too many format arguments in format string";
auto used_argument_index = extract_used_argument_index<N>(fmt, specifier_start_index, i, result.next_implicit_argument_index);
if (used_argument_index + 1 != result.next_implicit_argument_index)
result.has_explicit_argument_references = true;
result.used_arguments[result.total_used_argument_count++] = used_argument_index;
} else {
++result.extra_closed_braces;
}
break;
default:
continue;
}
}
return result;
}
}
template<size_t N, StringLiteral<N> fmt, size_t param_count, auto check = count_fmt_params<N>(fmt.data)>
constexpr bool check_format_parameter_consistency()
{
static_assert(check.internal_error.data[0] == 0, "Some internal error occured, try looking at the check function type for the error");
static_assert(check.unclosed_braces == 0, "Extra unclosed braces in format string");
static_assert(check.extra_closed_braces == 0, "Extra closing braces in format string");
{
constexpr auto begin = check.used_arguments.begin();
constexpr auto end = check.used_arguments.begin() + check.total_used_argument_count;
constexpr auto has_all_referenced_arguments = !AK::any_of(begin, end, [](auto& entry) { return entry >= param_count; });
static_assert(has_all_referenced_arguments, "Format string references nonexistent parameter");
}
if constexpr (!check.has_explicit_argument_references)
static_assert(check.total_used_argument_count == param_count, "Format string does not reference all passed parameters");
// Ensure that no passed parameter is ignored or otherwise not referenced in the format
// As this check is generally pretty expensive, try to avoid it where it cannot fail.
// We will only do this check if the format string has explicit argument refs
// otherwise, the check above covers this check too, as implicit refs
// monotonically increase, and cannot have 'gaps'.
if constexpr (check.has_explicit_argument_references) {
constexpr auto all_parameters = iota_array<size_t, param_count>(0);
auto contains = [](auto begin, auto end, auto entry) {
for (; begin != end; begin++) {
if (*begin == entry)
return true;
}
return false;
};
constexpr auto references_all_arguments = AK::all_of(
all_parameters.begin(),
all_parameters.end(),
[&](auto& entry) {
return contains(
check.used_arguments.begin(),
check.used_arguments.begin() + check.total_used_argument_count,
entry);
});
static_assert(references_all_arguments, "Format string does not reference all passed parameters");
}
return true;
}
template<auto fmt, auto param_count>
concept ConsistentFormatParameters = check_format_parameter_consistency<fmt.size, fmt, param_count>();
#endif
namespace AK {
class TypeErasedFormatParams;
@ -523,48 +370,38 @@ void vformat(const LogStream& stream, StringView fmtstr, TypeErasedFormatParams)
void vout(FILE*, StringView fmtstr, TypeErasedFormatParams, bool newline = false);
template<typename... Parameters>
void out(FILE* file, StringView fmtstr, const Parameters&... parameters) { vout(file, fmtstr, VariadicFormatParams { parameters... }); }
void out(FILE* file, CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters) { vout(file, fmtstr.view(), VariadicFormatParams { parameters... }); }
template<typename... Parameters>
void outln(FILE* file, StringView fmtstr, const Parameters&... parameters) { vout(file, fmtstr, VariadicFormatParams { parameters... }, true); }
template<typename... Parameters>
void outln(FILE* file, const char* fmtstr, const Parameters&... parameters) { vout(file, fmtstr, VariadicFormatParams { parameters... }, true); }
void outln(FILE* file, CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters) { vout(file, fmtstr.view(), VariadicFormatParams { parameters... }, true); }
inline void outln(FILE* file) { fputc('\n', file); }
template<typename... Parameters>
void out(StringView fmtstr, const Parameters&... parameters) { out(stdout, fmtstr, parameters...); }
void out(CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters) { out(stdout, move(fmtstr), parameters...); }
template<typename... Parameters>
void outln(StringView fmtstr, const Parameters&... parameters) { outln(stdout, fmtstr, parameters...); }
template<typename... Parameters>
void outln(const char* fmtstr, const Parameters&... parameters) { outln(stdout, fmtstr, parameters...); }
void outln(CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters) { outln(stdout, move(fmtstr), parameters...); }
inline void outln() { outln(stdout); }
template<typename... Parameters>
void warn(StringView fmtstr, const Parameters&... parameters) { out(stderr, fmtstr, parameters...); }
void warn(CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters) { out(stderr, move(fmtstr), parameters...); }
template<typename... Parameters>
void warnln(StringView fmtstr, const Parameters&... parameters) { outln(stderr, fmtstr, parameters...); }
template<typename... Parameters>
void warnln(const char* fmtstr, const Parameters&... parameters) { outln(stderr, fmtstr, parameters...); }
void warnln(CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters) { outln(stderr, move(fmtstr), parameters...); }
inline void warnln() { outln(stderr); }
#endif
void vdbgln(StringView fmtstr, TypeErasedFormatParams);
#ifndef DBGLN_NO_COMPILETIME_FORMAT_CHECK
template<StringLiteral fmt, bool enabled = true, typename... Parameters>
void dbgln(const Parameters&... parameters) requires ConsistentFormatParameters<fmt, sizeof...(Parameters)>
{
dbgln<enabled>(StringView { fmt.data }, parameters...);
}
#endif
template<bool enabled = true, typename... Parameters>
void dbgln(StringView fmtstr, const Parameters&... parameters)
void dbgln(CheckedFormatString<Parameters...>&& fmtstr, const Parameters&... parameters)
{
if constexpr (enabled)
vdbgln(fmtstr, VariadicFormatParams { parameters... });
vdbgln(fmtstr.view(), VariadicFormatParams { parameters... });
}
template<bool enabled = true, typename... Parameters>
void dbgln(const char* fmtstr, const Parameters&... parameters) { dbgln<enabled>(StringView { fmtstr }, parameters...); }
template<bool enabled = true>
void dbgln() { dbgln<enabled>(""); }
@ -575,10 +412,10 @@ void set_debug_enabled(bool);
void vdmesgln(StringView fmtstr, TypeErasedFormatParams);
template<typename... Parameters>
void dmesgln(StringView fmtstr, const Parameters&... parameters) { vdmesgln(fmtstr, VariadicFormatParams { parameters... }); }
template<typename... Parameters>
void dmesgln(const char* fmtstr, const Parameters&... parameters) { vdmesgln(fmtstr, VariadicFormatParams { parameters... }); }
inline void dmesgln() { dmesgln(""); }
void dmesgln(CheckedFormatString<Parameters...>&& fmt, const Parameters&... parameters)
{
vdmesgln(fmt.view(), VariadicFormatParams { parameters... });
}
#endif
template<typename T, typename = void>
@ -647,13 +484,8 @@ using AK::warnln;
using AK::dbgln;
using AK::CheckedFormatString;
using AK::FormatIfSupported;
using AK::FormatString;
#ifdef DBGLN_NO_COMPILETIME_FORMAT_CHECK
# define dbgln(fmt, ...) dbgln(fmt, ##__VA_ARGS__)
# define dbgln_if(flag, fmt, ...) dbgln<flag>(fmt, ##__VA_ARGS__)
#else
# define dbgln(fmt, ...) dbgln<fmt>(__VA_ARGS__)
# define dbgln_if(flag, fmt, ...) dbgln<fmt, flag>(__VA_ARGS__)
#endif
#define dbgln_if(flag, fmt, ...) dbgln<flag>(fmt, ##__VA_ARGS__)