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src: refactor EndsInANumber in node_url.cc and adds IsIPv4NumberValid #46227

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Merged
nodejs-github-bot merged 14 commits into from
Jan 23, 2023
Merged

src: refactor EndsInANumber in node_url.cc and adds IsIPv4NumberValid #46227

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ff9c478
src: refactor EndsInANumber in node_url.cc and adds IsIPv4NumberValid
miguelteixeiraa Jan 16, 2023
f076935
src: fix node_url.cc code formatting
miguelteixeiraa Jan 16, 2023
b1f4c83
src: fix node_url.cc code formatting (back to what it was)
miguelteixeiraa Jan 16, 2023
95d3081
src: refactor EndsInANumber in node_url.cc to use string_view::rfind
miguelteixeiraa Jan 17, 2023
e9282ad
src: fix imports typo in node_url.cc
miguelteixeiraa Jan 17, 2023
a683d34
src: removes unnecessary if statement from EndsInANumber in node_url.cc
miguelteixeiraa Jan 17, 2023
d165e39
src: use string_view instead of string in EndsInANumber in node_url.cc
miguelteixeiraa Jan 17, 2023
573dd4a
src: fix string_view constructor call for IsIPv4NumberValid in node_u…
miguelteixeiraa Jan 17, 2023
b52bbd4
src: adds minor tweaks to EndsInANumber at node_url.cc
miguelteixeiraa Jan 18, 2023
3074383
src: adds comment to IsIPv4NumberValid conditions in node_url.cc
miguelteixeiraa Jan 18, 2023
de4f065
src: cast interators to size_t in IsIPv4NumberValid call in node_url.cc
miguelteixeiraa Jan 18, 2023
9058eb5
src: cast interator to const char* in IsIPv4NumberValid call in node_…
miguelteixeiraa Jan 18, 2023
b65769f
src: use &(*it) to make windows build pass + ::all_of instead of ::fi…
miguelteixeiraa Jan 19, 2023
9534455
src: refactor EndsInANumber to be more readable in node_url.cc
miguelteixeiraa Jan 20, 2023
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61 changes: 47 additions & 14 deletions src/node_url.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -407,29 +407,62 @@ int64_t ParseIPv4Number(const char* start, const char* end) {
return strtoll(start, nullptr, R);
}

// https://url.spec.whatwg.org/#ipv4-number-parser
bool IsIPv4NumberValid(std::string_view input) {
if (input.empty()) {
return false;
}

if (input.size() >= 2 && input[0] == '0') {
if (input[1] == 'X' || input[1] == 'x') {
if (input.size() == 2) {
return true;
}

return input.find_first_not_of("0123456789abcdefABCDEF", 2) ==
std::string_view::npos;
} else {
return input.find_first_not_of("01234567", 1) == std::string_view::npos;
}
}

return std::all_of(input.begin(), input.end(), ::isdigit);
}

// https://url.spec.whatwg.org/#ends-in-a-number-checker
bool EndsInANumber(const std::string& input) {
std::vector<std::string> parts = SplitString(input, '.', false);
bool EndsInANumber(const std::string_view input) {
if (input.empty()) {
return false;
}

char delimiter = '.';
auto pointer_start = input.begin();
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@anonrig anonrig Jan 17, 2023

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If you use std::string_view::iterator it might solve the issues related to std::string_view construct on windows.

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023

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done!

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023

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Windows build is still failing : /

D:\a\node\node\src\node_url.cc(465,66): error C2440: '<function-style-cast>': cannot convert from 'initializer list' to 'std::string_view' [D:\a\node\node\libnode.vcxproj]
D:\a\node\node\src\node_url.cc(465,66): message : No constructor could take the source type, or constructor overload resolution was ambiguous [D:\a\node\node\libnode.vcxproj]
  node_util.cc

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023

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I would like to know if I can go with &(*it); again

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@anonrig anonrig Jan 18, 2023

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@addaleax any recommendations?

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023 •
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it'd look like this:
std::string_view(&(*pointer_start), pointer_end - pointer_start));
just to make the build pass on windows

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023 •
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What i understand is that iterators don't need to be pointers although they could be implemented as one. And some implementations of the STL (MSVC++, Mingw) implement interators with special classes (with no pre-difined casts to pointer), so that we cannot use them directly in the string_view constructor that we are using, which needs a charT*.

then we could use * which is overloaded to do what logically mean: convert the iterator type to its pointed-to object, then pass the address of this &(*it).

https://en.cppreference.com/w/cpp/named_req/RandomAccessIterator
https://stackoverflow.com/questions/32654108/c-stdvectoriterator-is-not-a-pointer-why/64910815#64910815

auto pointer_end = input.end();

if (parts.empty()) return false;
uint8_t parts_size = std::count(pointer_start, pointer_end, delimiter);
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@bnoordhuis bnoordhuis Jan 18, 2023

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Why uint8_t?

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023

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Because it's an IPv4, so there shouldn't be more parts than, lets say, 4. In short.. it would always be a small number (I think uint8_t still quite big for this)
but yeah.. maybe I should change to what std::count returns so it don't mess up the number..
Do you think it should be changed?

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@anonrig anonrig Jan 18, 2023

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uint8_t is correct. referencing spec:

A valid IPv4-address string must be four shortest possible strings of [ASCII digits]
(https://infra.spec.whatwg.org/#ascii-digit), representing a decimal number in the 
range 0 to 255, inclusive, separated from each other by U+002E (.).

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@addaleax addaleax Jan 18, 2023

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maybe I should change to what std::count returns so it don't mess up the number..

I think that’s a good idea, yeah. Reading this code it’s really not obvious that anything in the code guarantees that the return value fits into an uint8_t, even if that’s a type that can hold the all valid results. As an extreme case, if input contains 256 dots, parts_size would be 0 here, and I assume we don’t want to treat that the same as a string that doesn’t contain any dots.

++parts_size;

if (parts.back().empty()) {
if (parts.size() == 1) return false;
parts.pop_back();
if (input.back() == delimiter) {
--pointer_end;
--parts_size;
}

const std::string& last = parts.back();
if (parts_size > 1) {
pointer_start +=
input.rfind(delimiter, std::distance(pointer_start, pointer_end) - 1) +
1;
}

// If last is non-empty and contains only ASCII digits, then return true
if (!last.empty() && std::all_of(last.begin(), last.end(), ::isdigit)) {
return true;
if (std::distance(pointer_start, pointer_end) == 0) {
return false;
}

const char* last_str = last.c_str();
int64_t num = ParseIPv4Number(last_str, last_str + last.size());
if (num >= 0) return true;
if (std::all_of(pointer_start, pointer_end, ::isdigit)) {
return true;
}

return false;
return IsIPv4NumberValid(
std::string_view(&*pointer_start, pointer_end - pointer_start));
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@anonrig anonrig Jan 17, 2023

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This is too hacky (even if it's guaranteed safe).

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023

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removed!

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023 •
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I'll try a static_cast<const char*>

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@anonrig anonrig Jan 18, 2023

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@nodejs/cpp-reviewers any recommendations?

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@addaleax addaleax Jan 18, 2023

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Yeah: I would definitely recommeng to go back to the original "hacky" implementation. It works and looks correct, even if it is not visually pretty. (I'd also not call this pointer if it's an iterator.) const_cast<char*>(pointer_start) doesn't even really make sense since the string_view constructor takes a const char* argument.

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@miguelteixeiraa miguelteixeiraa Jan 18, 2023 •
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Yes, I think it only works on the other compilers because their implementations for the iterator are:
std::string_view::iterator' (aka 'const char *')
(I purposely caused an error to catch this 'aka' haha)

}

void URLHost::ParseIPv4Host(const char* input, size_t length) {
Expand Down