nix-store -r: Handle symlinks to store paths

Fixes #3270.

6 files changed, 56 insertions, 35 deletions

diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index c53dfdd56..8e9f9d71b 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -424,7 +424,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     case wopBuildPaths: {
         std::vector<StorePathWithOutputs> drvs;
         for (auto & s : readStrings<Strings>(from))
-            drvs.push_back(store->parseDrvPathWithOutputs(s));
+            drvs.push_back(store->parsePathWithOutputs(s));
         BuildMode mode = bmNormal;
         if (GET_PROTOCOL_MINOR(clientVersion) >= 15) {
             mode = (BuildMode) readInt(from);
@@ -721,7 +721,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     case wopQueryMissing: {
         std::vector<StorePathWithOutputs> targets;
         for (auto & s : readStrings<Strings>(from))
-            targets.push_back(store->parseDrvPathWithOutputs(s));
+            targets.push_back(store->parsePathWithOutputs(s));
         logger->startWork();
         StorePathSet willBuild, willSubstitute, unknown;
         unsigned long long downloadSize, narSize;
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 726e34479..1a061149a 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -375,16 +375,6 @@ Hash hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutput
 }
 
 
-StorePathWithOutputs Store::parseDrvPathWithOutputs(const std::string & s)
-{
-    size_t n = s.find("!");
-    return n == s.npos
-        ? StorePathWithOutputs{parseStorePath(s), std::set<string>()}
-        : StorePathWithOutputs{parseStorePath(std::string_view(s.data(), n)),
-            tokenizeString<std::set<string>>(string(s, n + 1), ",")};
-}
-
-
 std::string StorePathWithOutputs::to_string(const Store & store) const
 {
     return outputs.empty()
diff --git a/src/libstore/path.cc b/src/libstore/path.cc
index 81ae495a1..cda5f9968 100644
--- a/src/libstore/path.cc
+++ b/src/libstore/path.cc
@@ -96,4 +96,19 @@ StorePathSet singleton(const StorePath & path)
     return res;
 }
 
+std::pair<std::string_view, StringSet> parsePathWithOutputs(std::string_view s)
+{
+    size_t n = s.find("!");
+    return n == s.npos
+        ? std::make_pair(s, std::set<string>())
+        : std::make_pair(((std::string_view) s).substr(0, n),
+            tokenizeString<std::set<string>>(((std::string_view) s).substr(n + 1), ","));
+}
+
+StorePathWithOutputs Store::parsePathWithOutputs(const std::string & s)
+{
+    auto [path, outputs] = nix::parsePathWithOutputs(s);
+    return {parseStorePath(path), std::move(outputs)};
+}
+
 }
diff --git a/src/libstore/path.hh b/src/libstore/path.hh
index 273808f02..5ebb57480 100644
--- a/src/libstore/path.hh
+++ b/src/libstore/path.hh
@@ -7,6 +7,8 @@ namespace nix {
 /* See path.rs. */
 struct StorePath;
 
+struct Store;
+
 extern "C" {
     void ffi_StorePath_drop(void *);
     bool ffi_StorePath_less_than(const StorePath & a, const StorePath & b);
@@ -67,6 +69,28 @@ const size_t storePathHashLen = 32; // i.e. 160 bits
 /* Extension of derivations in the Nix store. */
 const std::string drvExtension = ".drv";
 
+struct StorePathWithOutputs
+{
+    StorePath path;
+    std::set<std::string> outputs;
+
+    StorePathWithOutputs(const StorePath & path, const std::set<std::string> & outputs = {})
+        : path(path.clone()), outputs(outputs)
+    { }
+
+    StorePathWithOutputs(StorePath && path, std::set<std::string> && outputs)
+        : path(std::move(path)), outputs(std::move(outputs))
+    { }
+
+    StorePathWithOutputs(const StorePathWithOutputs & other)
+        : path(other.path.clone()), outputs(other.outputs)
+    { }
+
+    std::string to_string(const Store & store) const;
+};
+
+std::pair<std::string_view, StringSet> parsePathWithOutputs(std::string_view s);
+
 }
 
 namespace std {
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index c98931885..1781e0c68 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -39,9 +39,9 @@ Path Store::toStorePath(const Path & path) const
 }
 
 
-Path Store::followLinksToStore(const Path & _path) const
+Path Store::followLinksToStore(std::string_view _path) const
 {
-    Path path = absPath(_path);
+    Path path = absPath(std::string(_path));
     while (!isInStore(path)) {
         if (!isLink(path)) break;
         string target = readLink(path);
@@ -53,12 +53,19 @@ Path Store::followLinksToStore(const Path & _path) const
 }
 
 
-StorePath Store::followLinksToStorePath(const Path & path) const
+StorePath Store::followLinksToStorePath(std::string_view path) const
 {
     return parseStorePath(toStorePath(followLinksToStore(path)));
 }
 
 
+StorePathWithOutputs Store::followLinksToStorePathWithOutputs(std::string_view path) const
+{
+    auto [path2, outputs] = nix::parsePathWithOutputs(path);
+    return StorePathWithOutputs(followLinksToStorePath(path2), std::move(outputs));
+}
+
+
 string storePathToHash(const Path & path)
 {
     auto base = baseNameOf(path);
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 552bbd67d..d77d6bad8 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -241,23 +241,6 @@ struct BuildResult
 };
 
 
-struct StorePathWithOutputs
-{
-    StorePath path;
-    std::set<std::string> outputs;
-
-    StorePathWithOutputs(const StorePath & path, const std::set<std::string> & outputs = {})
-        : path(path.clone()), outputs(outputs)
-    { }
-
-    StorePathWithOutputs(const StorePathWithOutputs & other)
-        : path(other.path.clone()), outputs(other.outputs)
-    { }
-
-    std::string to_string(const Store & store) const;
-};
-
-
 class Store : public std::enable_shared_from_this<Store>, public Config
 {
 public:
@@ -304,7 +287,7 @@ public:
     /* Split a string specifying a derivation and a set of outputs
        (/nix/store/hash-foo!out1,out2,...) into the derivation path
        and the outputs. */
-    StorePathWithOutputs parseDrvPathWithOutputs(const string & s);
+    StorePathWithOutputs parsePathWithOutputs(const string & s);
 
     /* Display a set of paths in human-readable form (i.e., between quotes
        and separated by commas). */
@@ -323,11 +306,13 @@ public:
     Path toStorePath(const Path & path) const;
 
     /* Follow symlinks until we end up with a path in the Nix store. */
-    Path followLinksToStore(const Path & path) const;
+    Path followLinksToStore(std::string_view path) const;
 
     /* Same as followLinksToStore(), but apply toStorePath() to the
        result. */
-    StorePath followLinksToStorePath(const Path & path) const;
+    StorePath followLinksToStorePath(std::string_view path) const;
+
+    StorePathWithOutputs followLinksToStorePathWithOutputs(std::string_view path) const;
 
     /* Constructs a unique store path name. */
     StorePath makeStorePath(const string & type,