From 8065c6d1606402e936b048aa75ad98ffdd7c8d60 Mon Sep 17 00:00:00 2001 From: John Ericson Date: Mon, 27 Jul 2020 20:45:34 +0000 Subject: [PATCH] Abstract out topo sorting logic --- src/libstore/misc.cc | 51 +++++++++++++--------------------------- src/libutil/topo-sort.hh | 40 +++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+), 35 deletions(-) create mode 100644 src/libutil/topo-sort.hh diff --git a/src/libstore/misc.cc b/src/libstore/misc.cc index c4d22a634..34a14d30d 100644 --- a/src/libstore/misc.cc +++ b/src/libstore/misc.cc @@ -4,6 +4,7 @@ #include "local-store.hh" #include "store-api.hh" #include "thread-pool.hh" +#include "topo-sort.hh" namespace nix { @@ -246,41 +247,21 @@ void Store::queryMissing(const std::vector & targets, StorePaths Store::topoSortPaths(const StorePathSet & paths) { - StorePaths sorted; - StorePathSet visited, parents; - - std::function dfsVisit; - - dfsVisit = [&](const StorePath & path, const StorePath * parent) { - if (parents.count(path)) - throw BuildError("cycle detected in the references of '%s' from '%s'", - printStorePath(path), printStorePath(*parent)); - - if (!visited.insert(path).second) return; - parents.insert(path); - - StorePathSet references; - try { - references = queryPathInfo(path)->references; - } catch (InvalidPath &) { - } - - for (auto & i : references) - /* Don't traverse into paths that don't exist. That can - happen due to substitutes for non-existent paths. */ - if (i != path && paths.count(i)) - dfsVisit(i, &path); - - sorted.push_back(path); - parents.erase(path); - }; - - for (auto & i : paths) - dfsVisit(i, nullptr); - - std::reverse(sorted.begin(), sorted.end()); - - return sorted; + return topoSort(paths, + {[&](const StorePath & path) { + StorePathSet references; + try { + references = queryPathInfo(path)->references; + } catch (InvalidPath &) { + } + return references; + }}, + {[&](const StorePath & path, const StorePath & parent) { + return BuildError( + "cycle detected in the references of '%s' from '%s'", + printStorePath(path), + printStorePath(parent)); + }}); } diff --git a/src/libutil/topo-sort.hh b/src/libutil/topo-sort.hh new file mode 100644 index 000000000..7a68ff169 --- /dev/null +++ b/src/libutil/topo-sort.hh @@ -0,0 +1,40 @@ +#include "error.hh" + +namespace nix { + +template +std::vector topoSort(std::set items, + std::function(const T &)> getChildren, + std::function makeCycleError) +{ + std::vector sorted; + std::set visited, parents; + + std::function dfsVisit; + + dfsVisit = [&](const T & path, const T * parent) { + if (parents.count(path)) throw makeCycleError(path, *parent); + + if (!visited.insert(path).second) return; + parents.insert(path); + + std::set references = getChildren(path); + + for (auto & i : references) + /* Don't traverse into items that don't exist in our starting set. */ + if (i != path && items.count(i)) + dfsVisit(i, &path); + + sorted.push_back(path); + parents.erase(path); + }; + + for (auto & i : items) + dfsVisit(i, nullptr); + + std::reverse(sorted.begin(), sorted.end()); + + return sorted; +} + +}