lix/src/libstore/names.cc
jade dde51af97d Use std::strong_ordering for version comparison
The actual motive here is the avoidance of integer overflow if we were
to make these use checked NixInts and retain the subtraction.

However, the actual *intent* of this code is a three-way comparison,
which can be done with operator<=>, so we should just do *that* instead.

Change-Id: I7f9a7da1f3176424b528af6d1b4f1591e4ab26bf
2024-07-12 16:48:28 +02:00

123 lines
2.9 KiB
C++

#include "names.hh"
#include "strings.hh"
#include <regex>
namespace nix {
struct Regex
{
std::regex regex;
};
DrvName::DrvName()
{
name = "";
}
/* Parse a derivation name. The `name' part of a derivation name is
everything up to but not including the first dash *not* followed by
a letter. The `version' part is the rest (excluding the separating
dash). E.g., `apache-httpd-2.0.48' is parsed to (`apache-httpd',
'2.0.48'). */
DrvName::DrvName(std::string_view s) : hits(0)
{
name = fullName = std::string(s);
for (unsigned int i = 0; i < s.size(); ++i) {
/* !!! isalpha/isdigit are affected by the locale. */
if (s[i] == '-' && i + 1 < s.size() && !isalpha(s[i + 1])) {
name = s.substr(0, i);
version = s.substr(i + 1);
break;
}
}
}
DrvName::~DrvName()
{ }
bool DrvName::matches(const DrvName & n)
{
if (name != "*") {
if (!regex) {
regex = std::make_unique<Regex>();
regex->regex = std::regex(name, std::regex::extended);
}
if (!std::regex_match(n.name, regex->regex)) return false;
}
if (version != "" && version != n.version) return false;
return true;
}
std::string_view nextComponent(std::string_view::const_iterator & p,
const std::string_view::const_iterator end)
{
/* Skip any dots and dashes (component separators). */
while (p != end && (*p == '.' || *p == '-')) ++p;
if (p == end) return "";
/* If the first character is a digit, consume the longest sequence
of digits. Otherwise, consume the longest sequence of
non-digit, non-separator characters. */
auto s = p;
if (isdigit(*p))
while (p != end && isdigit(*p)) p++;
else
while (p != end && (!isdigit(*p) && *p != '.' && *p != '-'))
p++;
return {s, size_t(p - s)};
}
static bool componentsLT(const std::string_view c1, const std::string_view c2)
{
auto n1 = string2Int<int>(c1);
auto n2 = string2Int<int>(c2);
if (n1 && n2) return *n1 < *n2;
else if (c1 == "" && n2) return true;
else if (c1 == "pre" && c2 != "pre") return true;
else if (c2 == "pre") return false;
/* Assume that `2.3a' < `2.3.1'. */
else if (n2) return true;
else if (n1) return false;
else return c1 < c2;
}
std::strong_ordering compareVersions(const std::string_view v1, const std::string_view v2)
{
auto p1 = v1.begin();
auto p2 = v2.begin();
while (p1 != v1.end() || p2 != v2.end()) {
auto c1 = nextComponent(p1, v1.end());
auto c2 = nextComponent(p2, v2.end());
if (componentsLT(c1, c2)) return std::strong_ordering::less;
else if (componentsLT(c2, c1)) return std::strong_ordering::greater;
}
return std::strong_ordering::equal;
}
DrvNames drvNamesFromArgs(const Strings & opArgs)
{
DrvNames result;
for (auto & i : opArgs)
result.emplace_back(i);
return result;
}
}