Checkpoint

src/libexpr/eval.cc

@@ -2070,14 +2070,14 @@ std::string EvalState::copyPathToStore(PathSet & context, const Path & path)
         auto path2 = unpackPath(path);
         #if 0
         auto p = settings.readOnlyMode
-            ? store->computeStorePathForPath(std::string(baseNameOf(path)), canonPath(path)).first
+            ? store->computeStorePathForPath(path2.baseName(), canonPath(path)).first
-            : store->addToStore(std::string(baseNameOf(path)), canonPath(path), FileIngestionMethod::Recursive, htSHA256, defaultPathFilter, repair);
+            : store->addToStore(path2.baseName(), canonPath(path), FileIngestionMethod::Recursive, htSHA256, defaultPathFilter, repair);
         #endif
         auto source = sinkToSource([&](Sink & sink) {
             path2.accessor->dumpPath(path2.path, sink);
         });
         // FIXME: readOnlyMode
-        auto p = store->addToStoreFromDump(*source, std::string(baseNameOf(path)), FileIngestionMethod::Recursive, htSHA256, repair);
+        auto p = store->addToStoreFromDump(*source, path2.baseName(), FileIngestionMethod::Recursive, htSHA256, repair);
         dstPath = store->printStorePath(p);
         allowPath(p);
         srcToStore.insert_or_assign(path, std::move(p));

src/libexpr/flake/flake.cc

@@ -209,7 +209,7 @@ static Flake getFlake(
         .originalRef = originalRef,
         .resolvedRef = resolvedRef,
         .lockedRef = lockedRef,
-        .sourceInfo = std::make_shared<fetchers::Tree>(std::move(sourceInfo))
+        //.sourceInfo = std::make_shared<fetchers::Tree>(std::move(sourceInfo))
     };
 
     if (!pathExists(flakeFile))
@@ -326,6 +326,7 @@ LockedFlake lockFlake(
         state.store->setOptions();
     }
 
+    #if 0
     try {
 
         // FIXME: symlink attack
@@ -669,6 +670,9 @@ LockedFlake lockFlake(
         e.addTrace({}, "while updating the lock file of flake '%s'", flake.lockedRef.to_string());
         throw;
     }
+    #endif
+
+    throw UnimplementedError("lockFlake");
 }
 
 void callFlake(EvalState & state,
@@ -683,13 +687,17 @@ void callFlake(EvalState & state,
 
     vLocks->mkString(lockedFlake.lockFile.to_string());
 
+    #if 0
     emitTreeAttrs(
         state,
-        *lockedFlake.flake.sourceInfo,
+        //*lockedFlake.flake.sourceInfo,
         lockedFlake.flake.lockedRef.input,
         *vRootSrc,
         false,
         lockedFlake.flake.forceDirty);
+    #endif
+
+    throw UnimplementedError("callFlake");
 
     vRootSubdir->mkString(lockedFlake.flake.lockedRef.subdir);
 
@@ -756,7 +764,8 @@ Fingerprint LockedFlake::getFingerprint() const
     // flake.sourceInfo.storePath for the fingerprint.
     return hashString(htSHA256,
         fmt("%s;%s;%d;%d;%s",
-            flake.sourceInfo->storePath.to_string(),
+            "FIXME",
+            //flake.sourceInfo->storePath.to_string(),
             flake.lockedRef.subdir,
             flake.lockedRef.input.getRevCount().value_or(0),
             flake.lockedRef.input.getLastModified().value_or(0),

src/libexpr/flake/flake.hh

@@ -63,7 +63,6 @@ struct Flake
     FlakeRef lockedRef; // the specific local store result of invoking the fetcher
     bool forceDirty = false; // pretend that 'lockedRef' is dirty
     std::optional<std::string> description;
-    std::shared_ptr<const fetchers::Tree> sourceInfo;
     FlakeInputs inputs;
     ConfigFile config; // 'nixConfig' attribute
     ~Flake();
@@ -139,7 +138,7 @@ void callFlake(
 
 void emitTreeAttrs(
     EvalState & state,
-    const fetchers::Tree & tree,
+    const SourcePath & path,
     const fetchers::Input & input,
     Value & v,
     bool emptyRevFallback = false,

src/libexpr/paths.cc

@@ -16,15 +16,14 @@ Path EvalState::packPath(const SourcePath & path)
 
 SourcePath EvalState::unpackPath(const Path & path)
 {
+    printError("UNPACK %s", path);
     if (hasPrefix(path, marker)) {
         auto s = path.substr(marker.size());
         auto slash = s.find('/');
-        assert(slash != s.npos);
         auto n = std::stoi(s.substr(0, slash));
-        printError("GOT %d", n);
         auto i = inputAccessors.find(n);
         assert(i != inputAccessors.end());
-        return {i->second, s.substr(slash)};
+        return {i->second, slash != std::string::npos ? s.substr(slash) : "/"};
     } else {
         printError("FIXME: %s", path);
         return rootPath(path);

src/libexpr/primops/fetchTree.cc

@@ -13,25 +13,32 @@ namespace nix {
 
 void emitTreeAttrs(
     EvalState & state,
-    const fetchers::Tree & tree,
+    const SourcePath & path,
     const fetchers::Input & input,
     Value & v,
     bool emptyRevFallback,
     bool forceDirty)
 {
-    assert(input.isLocked());
+    // FIXME?
+    //assert(input.isLocked());
 
     auto attrs = state.buildBindings(8);
 
+    #if 0
     auto storePath = state.store->printStorePath(tree.storePath);
 
     attrs.alloc(state.sOutPath).mkString(storePath, {storePath});
+    #endif
+
+    attrs.alloc(state.sOutPath).mkPath(state.packPath(path));
 
     // FIXME: support arbitrary input attributes.
 
+    #if 0
     auto narHash = input.getNarHash();
     assert(narHash);
     attrs.alloc("narHash").mkString(narHash->to_string(SRI, true));
+    #endif
 
     if (input.getType() == "git")
         attrs.alloc("submodules").mkBool(
@@ -169,11 +176,17 @@ static void fetchTree(
     if (evalSettings.pureEval && !input.isLocked())
         throw Error("in pure evaluation mode, 'fetchTree' requires a locked input, at %s", pos);
 
-    auto [tree, input2] = input.fetch(state.store);
+    auto [accessor, input2] = input.lazyFetch(state.store);
 
-    state.allowPath(tree.storePath);
+    //state.allowPath(tree.storePath);
 
-    emitTreeAttrs(state, tree, input2, v, params.emptyRevFallback, false);
+    emitTreeAttrs(
+        state,
+        {accessor, "/"},
+        input2,
+        v,
+        params.emptyRevFallback,
+        false);
 }
 
 static void prim_fetchTree(EvalState & state, const Pos & pos, Value * * args, Value & v)

src/libfetchers/fetchers.cc

@@ -172,6 +172,19 @@ std::pair<Tree, Input> Input::fetch(ref<Store> store) const
     return {std::move(tree), input};
 }
 
+std::pair<ref<InputAccessor>, Input> Input::lazyFetch(ref<Store> store) const
+{
+    if (!scheme)
+        throw Error("cannot fetch unsupported input '%s'", attrsToJSON(toAttrs()));
+
+    try {
+        return scheme->lazyFetch(store, *this);
+    } catch (Error & e) {
+        e.addTrace({}, "while fetching the input '%s'", to_string());
+        throw;
+    }
+}
+
 Input Input::applyOverrides(
     std::optional<std::string> ref,
     std::optional<Hash> rev) const
@@ -289,4 +302,11 @@ void InputScheme::clone(const Input & input, const Path & destDir)
     throw Error("do not know how to clone input '%s'", input.to_string());
 }
 
+std::pair<ref<InputAccessor>, Input> InputScheme::lazyFetch(ref<Store> store, const Input & input)
+{
+    auto [storePath, input2] = fetch(store, input);
+
+    return {makeFSInputAccessor(store->toRealPath(storePath)), input2};
+}
+
 }

src/libfetchers/fetchers.hh

@@ -73,6 +73,11 @@ public:
        the Nix store and the locked input. */
     std::pair<Tree, Input> fetch(ref<Store> store) const;
 
+    /* Return an InputAccessor that allows access to files in the
+       input without copying it to the store. Also return a possibly
+       unlocked input. */
+    std::pair<ref<InputAccessor>, Input> lazyFetch(ref<Store> store) const;
+
     Input applyOverrides(
         std::optional<std::string> ref,
         std::optional<Hash> rev) const;
@@ -132,6 +137,8 @@ struct InputScheme
 
     virtual std::pair<StorePath, Input> fetch(ref<Store> store, const Input & input) = 0;
 
+    virtual std::pair<ref<InputAccessor>, Input> lazyFetch(ref<Store> store, const Input & input);
+
     virtual ref<InputAccessor> getAccessor()
     {
         throw UnimplementedError("getAccessor");

src/libfetchers/input-accessor.cc

@@ -14,7 +14,7 @@ InputAccessor::InputAccessor()
 // FIXME: merge with archive.cc.
 const std::string narVersionMagic1 = "nix-archive-1";
 
-static string caseHackSuffix = "~nix~case~hack~";
+static std::string caseHackSuffix = "~nix~case~hack~";
 
 void InputAccessor::dumpPath(
     const Path & path,
@@ -51,12 +51,12 @@ void InputAccessor::dumpPath(
 
             /* If we're on a case-insensitive system like macOS, undo
                the case hack applied by restorePath(). */
-            std::map<string, string> unhacked;
+            std::map<std::string, std::string> unhacked;
             for (auto & i : readDirectory(path))
                 if (/* archiveSettings.useCaseHack */ false) { // FIXME
-                    string name(i.first);
+                    std::string name(i.first);
                     size_t pos = i.first.find(caseHackSuffix);
-                    if (pos != string::npos) {
+                    if (pos != std::string::npos) {
                         debug(format("removing case hack suffix from '%s'") % (path + "/" + i.first));
                         name.erase(pos);
                     }
@@ -227,4 +227,10 @@ ref<MemoryInputAccessor> makeMemoryInputAccessor()
     return make_ref<MemoryInputAccessorImpl>();
 }
 
+std::string_view SourcePath::baseName() const
+{
+    // FIXME
+    return path == "" || path == "/" ? "source" : baseNameOf(path);
+}
+
 }

src/libfetchers/input-accessor.hh

@@ -57,6 +57,8 @@ struct SourcePath
 {
     ref<InputAccessor> accessor;
     Path path;
+
+    std::string_view baseName() const;
 };
 
 std::ostream & operator << (std::ostream & str, const SourcePath & path);

src/libfetchers/path.cc

@@ -81,29 +81,36 @@ struct PathInputScheme : InputScheme
         // nothing to do
     }
 
+    Path getAbsPath(ref<Store> store, const Input & input)
+    {
+        auto path = getStrAttr(input.attrs, "path");
+
+        if (path[0] == '/')
+            return path;
+
+        if (!input.parent)
+            throw Error("cannot fetch input '%s' because it uses a relative path", input.to_string());
+
+        auto parent = canonPath(*input.parent);
+
+        // the path isn't relative, prefix it
+        auto absPath = nix::absPath(path, parent);
+
+        // for security, ensure that if the parent is a store path, it's inside it
+        if (store->isInStore(parent)) {
+            auto storePath = store->printStorePath(store->toStorePath(parent).first);
+            if (!isDirOrInDir(absPath, storePath))
+                throw BadStorePath("relative path '%s' points outside of its parent's store path '%s'", path, storePath);
+        }
+
+        return absPath;
+    }
+
     std::pair<StorePath, Input> fetch(ref<Store> store, const Input & _input) override
     {
         Input input(_input);
-        std::string absPath;
-        auto path = getStrAttr(input.attrs, "path");
 
-        if (path[0] != '/') {
+        auto absPath = getAbsPath(store, input);
-            if (!input.parent)
-                throw Error("cannot fetch input '%s' because it uses a relative path", input.to_string());
-
-            auto parent = canonPath(*input.parent);
-
-            // the path isn't relative, prefix it
-            absPath = nix::absPath(path, parent);
-
-            // for security, ensure that if the parent is a store path, it's inside it
-            if (store->isInStore(parent)) {
-                auto storePath = store->printStorePath(store->toStorePath(parent).first);
-                if (!isDirOrInDir(absPath, storePath))
-                    throw BadStorePath("relative path '%s' points outside of its parent's store path '%s'", path, storePath);
-            }
-        } else
-            absPath = path;
 
         Activity act(*logger, lvlTalkative, actUnknown, fmt("copying '%s'", absPath));
 
@@ -125,6 +132,14 @@ struct PathInputScheme : InputScheme
 
         return {std::move(*storePath), input};
     }
+
+    std::pair<ref<InputAccessor>, Input> lazyFetch(ref<Store> store, const Input & input) override
+    {
+        auto absPath = getAbsPath(store, input);
+        auto input2(input);
+        input2.attrs.emplace("path", absPath);
+        return {makeFSInputAccessor(absPath), std::move(input2)};
+    }
 };
 
 static auto rPathInputScheme = OnStartup([] { registerInputScheme(std::make_unique<PathInputScheme>()); });

src/nix/flake.cc

@@ -182,7 +182,9 @@ struct CmdFlakeMetadata : FlakeCommand, MixJSON
                 j["revCount"] = *revCount;
             if (auto lastModified = flake.lockedRef.input.getLastModified())
                 j["lastModified"] = *lastModified;
+            #if 0
             j["path"] = store->printStorePath(flake.sourceInfo->storePath);
+            #endif
             j["locks"] = lockedFlake.lockFile.toJSON();
             logger->cout("%s", j.dump());
         } else {
@@ -196,9 +198,11 @@ struct CmdFlakeMetadata : FlakeCommand, MixJSON
                 logger->cout(
                     ANSI_BOLD "Description:" ANSI_NORMAL "   %s",
                     *flake.description);
+            #if 0
             logger->cout(
                 ANSI_BOLD "Path:" ANSI_NORMAL "          %s",
                 store->printStorePath(flake.sourceInfo->storePath));
+            #endif
             if (auto rev = flake.lockedRef.input.getRev())
                 logger->cout(
                     ANSI_BOLD "Revision:" ANSI_NORMAL "      %s",
@@ -881,6 +885,8 @@ struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun
 
         StorePathSet sources;
 
+        throw UnimplementedError("flake archive");
+        #if 0
         sources.insert(flake.flake.sourceInfo->storePath);
         if (jsonRoot)
             jsonRoot->attr("path", store->printStorePath(flake.flake.sourceInfo->storePath));
@@ -911,6 +917,7 @@ struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun
             ref<Store> dstStore = dstUri.empty() ? openStore() : openStore(dstUri);
             copyPaths(*store, *dstStore, sources);
         }
+        #endif
     }
 };