lix/src/libstore/fetchers/parse.cc

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#include "parse.hh"
#include "util.hh"
#include "regex.hh"
namespace nix::fetchers {
std::regex refRegex(refRegexS, std::regex::ECMAScript);
std::regex revRegex(revRegexS, std::regex::ECMAScript);
Respect lock files of inputs + fine-grained lock file control When computing a lock file, we now respect the lock files of flake inputs. This is important for usability / reproducibility. For example, the 'nixops' flake depends on the 'nixops-aws' and 'nixops-hetzner' repositories. So when the 'nixops' flake is used in another flake, we want the versions of 'nixops-aws' and 'nixops-hetzner' locked by the the 'nixops' flake because those presumably have been tested. This can lead to a proliferation of versions of flakes like 'nixpkgs' (since every flake's lock file could depend on a different version of 'nixpkgs'). This is not a major issue when using Nixpkgs overlays or NixOS modules, since then the top-level flake composes those overlays/modules into *its* version of Nixpkgs and all other versions are ignored. Lock file computation has been made a bit more lazy so it won't try to fetch all those versions of 'nixpkgs'. However, in case it's necessary to minimize flake versions, there now are two input attributes that allow this. First, you can copy an input from another flake, as follows: inputs.nixpkgs.follows = "dwarffs/nixpkgs"; This states that the calling flake's 'nixpkgs' input shall be the same as the 'nixpkgs' input of the 'dwarffs' input. Second, you can override inputs of inputs: inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; inputs.nixops.inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; or equivalently, using 'follows': inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; inputs.nixops.inputs.nixpkgs.follows = "nixpkgs"; This states that the 'nixpkgs' input of the 'nixops' input shall be the same as the calling flake's 'nixpkgs' input. Finally, at '-v' Nix now prints the changes to the lock file, e.g. $ nix flake update ~/Misc/eelco-configurations/hagbard inputs of flake 'git+file:///home/eelco/Misc/eelco-configurations?subdir=hagbard' changed: updated 'nixpkgs': 'github:edolstra/nixpkgs/7845bf5f4b3013df1cf036e9c9c3a55a30331db9' -> 'github:edolstra/nixpkgs/03f3def66a104a221aac8b751eeb7075374848fd' removed 'nixops' removed 'nixops/nixops-aws' removed 'nixops/nixops-hetzner' removed 'nixops/nixpkgs'
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std::regex flakeIdRegex(flakeIdRegexS, std::regex::ECMAScript);
ParsedURL parseURL(const std::string & url)
{
static std::regex uriRegex(
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"((" + schemeRegex + "):"
+ "(?:(?://(" + authorityRegex + ")(" + absPathRegex + "))|(/?" + pathRegex + ")))"
+ "(?:\\?(" + queryRegex + "))?"
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+ "(?:#(" + queryRegex + "))?",
std::regex::ECMAScript);
std::smatch match;
if (std::regex_match(url, match, uriRegex)) {
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auto & base = match[1];
std::string scheme = match[2];
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auto authority = match[3].matched
? std::optional<std::string>(match[3]) : std::nullopt;
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std::string path = match[4].matched ? match[4] : match[5];
auto & query = match[6];
auto & fragment = match[7];
auto isFile = scheme.find("file") != std::string::npos;
if (authority && *authority != "" && isFile)
throw Error("file:// URL '%s' has unexpected authority '%s'",
url, *authority);
if (isFile && path.empty())
path = "/";
return ParsedURL{
.url = url,
.base = base,
.scheme = scheme,
.authority = authority,
.path = path,
.query = decodeQuery(query),
.fragment = percentDecode(std::string(fragment))
};
}
else
throw BadURL("'%s' is not a valid URL", url);
}
std::string percentDecode(std::string_view in)
{
std::string decoded;
for (size_t i = 0; i < in.size(); ) {
if (in[i] == '%') {
if (i + 2 >= in.size())
throw BadURL("invalid URI parameter '%s'", in);
try {
decoded += std::stoul(std::string(in, i + 1, 2), 0, 16);
i += 3;
} catch (...) {
throw BadURL("invalid URI parameter '%s'", in);
}
} else
decoded += in[i++];
}
return decoded;
}
std::map<std::string, std::string> decodeQuery(const std::string & query)
{
std::map<std::string, std::string> result;
for (auto s : tokenizeString<Strings>(query, "&")) {
auto e = s.find('=');
if (e != std::string::npos)
result.emplace(
s.substr(0, e),
percentDecode(std::string_view(s).substr(e + 1)));
}
return result;
}
std::string percentEncode(std::string_view s)
{
std::string res;
for (auto & c : s)
if ((c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| (c >= '0' && c <= '9')
|| strchr("-._~!$&'()*+,;=:@", c))
res += c;
else
res += fmt("%%%02x", (unsigned int) c);
return res;
}
std::string encodeQuery(const std::map<std::string, std::string> & ss)
{
std::string res;
bool first = true;
for (auto & [name, value] : ss) {
if (!first) res += '&';
first = false;
res += percentEncode(name);
res += '=';
res += percentEncode(value);
}
return res;
}
std::string ParsedURL::to_string() const
{
return
scheme
+ ":"
+ (authority ? "//" + *authority : "")
+ path
+ (query.empty() ? "" : "?" + encodeQuery(query))
+ (fragment.empty() ? "" : "#" + percentEncode(fragment));
}
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bool ParsedURL::operator ==(const ParsedURL & other) const
{
return
scheme == other.scheme
&& authority == other.authority
&& path == other.path
&& query == other.query
&& fragment == other.fragment;
}
}