Nix/src/libexpr/eval-settings.cc
John Ericson ac89bb064a Split up util.{hh,cc}
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.

This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.

Newly exposed functions to break cycles:

 - `restoreSignals`
 - `updateWindowSize`
2023-11-05 12:20:02 -05:00

104 lines
2.5 KiB
C++

#include "users.hh"
#include "globals.hh"
#include "profiles.hh"
#include "eval.hh"
#include "eval-settings.hh"
namespace nix {
/* Very hacky way to parse $NIX_PATH, which is colon-separated, but
can contain URLs (e.g. "nixpkgs=https://bla...:foo=https://"). */
static Strings parseNixPath(const std::string & s)
{
Strings res;
auto p = s.begin();
while (p != s.end()) {
auto start = p;
auto start2 = p;
while (p != s.end() && *p != ':') {
if (*p == '=') start2 = p + 1;
++p;
}
if (p == s.end()) {
if (p != start) res.push_back(std::string(start, p));
break;
}
if (*p == ':') {
auto prefix = std::string(start2, s.end());
if (EvalSettings::isPseudoUrl(prefix) || hasPrefix(prefix, "flake:")) {
++p;
while (p != s.end() && *p != ':') ++p;
}
res.push_back(std::string(start, p));
if (p == s.end()) break;
}
++p;
}
return res;
}
EvalSettings::EvalSettings()
{
auto var = getEnv("NIX_PATH");
if (var) nixPath = parseNixPath(*var);
}
Strings EvalSettings::getDefaultNixPath()
{
Strings res;
auto add = [&](const Path & p, const std::string & s = std::string()) {
if (pathAccessible(p)) {
if (s.empty()) {
res.push_back(p);
} else {
res.push_back(s + "=" + p);
}
}
};
if (!evalSettings.restrictEval && !evalSettings.pureEval) {
add(getNixDefExpr() + "/channels");
add(rootChannelsDir() + "/nixpkgs", "nixpkgs");
add(rootChannelsDir());
}
return res;
}
bool EvalSettings::isPseudoUrl(std::string_view s)
{
if (s.compare(0, 8, "channel:") == 0) return true;
size_t pos = s.find("://");
if (pos == std::string::npos) return false;
std::string scheme(s, 0, pos);
return scheme == "http" || scheme == "https" || scheme == "file" || scheme == "channel" || scheme == "git" || scheme == "s3" || scheme == "ssh";
}
std::string EvalSettings::resolvePseudoUrl(std::string_view url)
{
if (hasPrefix(url, "channel:"))
return "https://nixos.org/channels/" + std::string(url.substr(8)) + "/nixexprs.tar.xz";
else
return std::string(url);
}
EvalSettings evalSettings;
static GlobalConfig::Register rEvalSettings(&evalSettings);
Path getNixDefExpr()
{
return settings.useXDGBaseDirectories
? getStateDir() + "/nix/defexpr"
: getHome() + "/.nix-defexpr";
}
}