lix-releng-staging/src/libexpr/names.cc
Eelco Dolstra bbe97dff8b Make the Store API more type-safe
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
2019-12-10 22:06:05 +01:00

108 lines
2.7 KiB
C++

#include "names.hh"
#include "util.hh"
namespace nix {
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;
}
}
}
bool DrvName::matches(DrvName & n)
{
if (name != "*") {
if (!regex) regex = std::unique_ptr<std::regex>(new std::regex(name, std::regex::extended));
if (!std::regex_match(n.name, *regex)) return false;
}
if (version != "" && version != n.version) return false;
return true;
}
string nextComponent(string::const_iterator & p,
const string::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. */
string s;
if (isdigit(*p))
while (p != end && isdigit(*p)) s += *p++;
else
while (p != end && (!isdigit(*p) && *p != '.' && *p != '-'))
s += *p++;
return s;
}
static bool componentsLT(const string & c1, const string & c2)
{
int n1, n2;
bool c1Num = string2Int(c1, n1), c2Num = string2Int(c2, n2);
if (c1Num && c2Num) return n1 < n2;
else if (c1 == "" && c2Num) 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 (c2Num) return true;
else if (c1Num) return false;
else return c1 < c2;
}
int compareVersions(const string & v1, const string & v2)
{
string::const_iterator p1 = v1.begin();
string::const_iterator p2 = v2.begin();
while (p1 != v1.end() || p2 != v2.end()) {
string c1 = nextComponent(p1, v1.end());
string c2 = nextComponent(p2, v2.end());
if (componentsLT(c1, c2)) return -1;
else if (componentsLT(c2, c1)) return 1;
}
return 0;
}
DrvNames drvNamesFromArgs(const Strings & opArgs)
{
DrvNames result;
for (auto & i : opArgs)
result.push_back(DrvName(i));
return result;
}
}