From 12f9379123eba828f2ae06f7978a37b7045c2b23 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Thu, 2 Apr 2020 14:56:20 +0200 Subject: [PATCH] Add 'path' fetcher This fetchers copies a plain directory (i.e. not a Git/Mercurial repository) to the store (or does nothing if the path is already a store path). One use case is to pin the 'nixpkgs' flake used to build the current NixOS system, and prevent it from being garbage-collected, via a system registry entry like this: { "from": { "id": "nixpkgs", "type": "indirect" }, "to": { "type": "path", "path": "/nix/store/rralhl3wj4rdwzjn16g7d93mibvlr521-source", "lastModified": 1585388205, "rev": "b0c285807d6a9f1b7562ec417c24fa1a30ecc31a" }, "exact": true } Note the fake "lastModified" and "rev" attributes that ensure that the flake gives the same evaluation results as the corresponding Git/GitHub inputs. --- src/libfetchers/attrs.cc | 15 +++++ src/libfetchers/attrs.hh | 2 + src/libfetchers/path.cc | 130 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 147 insertions(+) create mode 100644 src/libfetchers/path.cc diff --git a/src/libfetchers/attrs.cc b/src/libfetchers/attrs.cc index 40c02de42..feb0a6085 100644 --- a/src/libfetchers/attrs.cc +++ b/src/libfetchers/attrs.cc @@ -89,4 +89,19 @@ bool getBoolAttr(const Attrs & attrs, const std::string & name) return *s; } +std::map attrsToQuery(const Attrs & attrs) +{ + std::map query; + for (auto & attr : attrs) { + if (auto v = std::get_if(&attr.second)) { + query.insert_or_assign(attr.first, fmt("%d", *v)); + } else if (auto v = std::get_if(&attr.second)) { + query.insert_or_assign(attr.first, *v); + } else if (auto v = std::get_if>(&attr.second)) { + query.insert_or_assign(attr.first, v->t ? "1" : "0"); + } else abort(); + } + return query; +} + } diff --git a/src/libfetchers/attrs.hh b/src/libfetchers/attrs.hh index 2c9e772d2..d6e0ae000 100644 --- a/src/libfetchers/attrs.hh +++ b/src/libfetchers/attrs.hh @@ -34,4 +34,6 @@ std::optional maybeGetBoolAttr(const Attrs & attrs, const std::string & na bool getBoolAttr(const Attrs & attrs, const std::string & name); +std::map attrsToQuery(const Attrs & attrs); + } diff --git a/src/libfetchers/path.cc b/src/libfetchers/path.cc new file mode 100644 index 000000000..9801d9b86 --- /dev/null +++ b/src/libfetchers/path.cc @@ -0,0 +1,130 @@ +#include "fetchers.hh" +#include "store-api.hh" + +namespace nix::fetchers { + +struct PathInput : Input +{ + Path path; + + /* Allow the user to pass in "fake" tree info attributes. This is + useful for making a pinned tree work the same as the repository + from which is exported + (e.g. path:/nix/store/...-source?lastModified=1585388205&rev=b0c285...). */ + std::optional rev; + std::optional revCount; + std::optional lastModified; + + std::string type() const override { return "path"; } + + std::optional getRev() const override { return rev; } + + ParsedURL toURL() const override + { + auto query = attrsToQuery(toAttrsInternal()); + query.erase("path"); + return ParsedURL { + .scheme = "path", + .path = path, + .query = query, + }; + } + + Attrs toAttrsInternal() const override + { + Attrs attrs; + attrs.emplace("path", path); + if (rev) + attrs.emplace("rev", rev->gitRev()); + if (revCount) + attrs.emplace("revCount", *revCount); + if (lastModified) + attrs.emplace("lastModified", *lastModified); + return attrs; + } + + std::pair> fetchTreeInternal(nix::ref store) const override + { + auto input = std::make_shared(*this); + + auto storePath = store->maybeParseStorePath(path); + + if (storePath) + store->addTempRoot(*storePath); + + if (!storePath || storePath->name() != "source" || !store->isValidPath(*storePath)) + // FIXME: try to substitute storePath. + storePath = store->addToStore("name", path); + + return + { + Tree { + .actualPath = store->toRealPath(*storePath), + .storePath = std::move(*storePath), + .info = TreeInfo { + .revCount = revCount, + .lastModified = lastModified + } + }, + input + }; + } + +}; + +struct PathInputScheme : InputScheme +{ + std::unique_ptr inputFromURL(const ParsedURL & url) override + { + if (url.scheme != "path") return nullptr; + + auto input = std::make_unique(); + input->path = url.path; + + for (auto & [name, value] : url.query) + if (name == "rev") + input->rev = Hash(value, htSHA1); + else if (name == "revCount") { + uint64_t revCount; + if (!string2Int(value, revCount)) + throw Error("path URL '%s' has invalid parameter '%s'", url.to_string(), name); + input->revCount = revCount; + } + else if (name == "lastModified") { + time_t lastModified; + if (!string2Int(value, lastModified)) + throw Error("path URL '%s' has invalid parameter '%s'", url.to_string(), name); + input->lastModified = lastModified; + } + else + throw Error("path URL '%s' has unsupported parameter '%s'", url.to_string(), name); + + return input; + } + + std::unique_ptr inputFromAttrs(const Attrs & attrs) override + { + if (maybeGetStrAttr(attrs, "type") != "path") return {}; + + auto input = std::make_unique(); + input->path = getStrAttr(attrs, "path"); + + for (auto & [name, value] : attrs) + if (name == "rev") + input->rev = Hash(getStrAttr(attrs, "rev"), htSHA1); + else if (name == "revCount") + input->revCount = getIntAttr(attrs, "revCount"); + else if (name == "lastModified") + input->lastModified = getIntAttr(attrs, "lastModified"); + else if (name == "type" || name == "path") + ; + else + throw Error("unsupported path input attribute '%s'", name); + + return input; + } +}; + +static auto r1 = OnStartup([] { registerInputScheme(std::make_unique()); }); + +}