Merge branch 'hash-always-has-type' into better-ca-parse-errors

.dir-locals.el

@@ -1,6 +1,7 @@
 ((c++-mode . (
   (c-file-style . "k&r")
   (c-basic-offset . 4)
+  (c-block-comment-prefix . "  ")
   (indent-tabs-mode . nil)
   (tab-width . 4)
   (show-trailing-whitespace . t)

src/libstore/content-address.cc

@@ -92,4 +92,16 @@ std::string renderContentAddress(std::optional<ContentAddress> ca) {
     return ca ? renderContentAddress(*ca) : "";
 }
 
+Hash getContentAddressHash(const ContentAddress & ca)
+{
+    return std::visit(overloaded {
+        [](TextHash th) {
+            return th.hash;
+        },
+        [](FixedOutputHash fsh) {
+            return fsh.hash;
+        }
+    }, ca);
+}
+
 }

src/libstore/content-address.hh

@@ -53,4 +53,6 @@ ContentAddress parseContentAddress(std::string_view rawCa);
 
 std::optional<ContentAddress> parseContentAddressOpt(std::string_view rawCaOpt);
 
+Hash getContentAddressHash(const ContentAddress & ca);
+
 }

src/libstore/store-api.cc

@@ -7,6 +7,7 @@
 #include "json.hh"
 #include "derivations.hh"
 #include "url.hh"
+#include "archive.hh"
 
 #include <future>
 
@@ -221,6 +222,40 @@ StorePath Store::computeStorePathForText(const string & name, const string & s,
 }
 
 
+ValidPathInfo Store::addToStoreSlow(std::string_view name, const Path & srcPath,
+    FileIngestionMethod method, HashType hashAlgo,
+    std::optional<Hash> expectedCAHash)
+{
+    /* FIXME: inefficient: we're reading/hashing 'tmpFile' three
+       times. */
+
+    auto [narHash, narSize] = hashPath(htSHA256, srcPath);
+
+    auto hash = method == FileIngestionMethod::Recursive
+        ? hashAlgo == htSHA256
+          ? narHash
+          : hashPath(hashAlgo, srcPath).first
+        : hashFile(hashAlgo, srcPath);
+
+    if (expectedCAHash && expectedCAHash != hash)
+        throw Error("hash mismatch for '%s'", srcPath);
+
+    ValidPathInfo info(makeFixedOutputPath(method, hash, name));
+    info.narHash = narHash;
+    info.narSize = narSize;
+    info.ca = FixedOutputHash { .method = method, .hash = hash };
+
+    if (!isValidPath(info.path)) {
+        auto source = sinkToSource([&](Sink & sink) {
+            dumpPath(srcPath, sink);
+        });
+        addToStore(info, *source);
+    }
+
+    return info;
+}
+
+
 Store::Store(const Params & params)
     : Config(params)
     , state({(size_t) pathInfoCacheSize})

src/libstore/store-api.hh

@@ -451,6 +451,13 @@ public:
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256,
         PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair) = 0;
 
+    /* Copy the contents of a path to the store and register the
+       validity the resulting path, using a constant amount of
+       memory. */
+    ValidPathInfo addToStoreSlow(std::string_view name, const Path & srcPath,
+        FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256,
+        std::optional<Hash> expectedCAHash = {});
+
     // FIXME: remove?
     virtual StorePath addToStoreFromDump(const string & dump, const string & name,
         FileIngestionMethod method = FileIngestionMethod::Recursive, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair)

src/nix-prefetch-url/nix-prefetch-url.cc

@@ -153,14 +153,15 @@ static int _main(int argc, char * * argv)
 
         /* If an expected hash is given, the file may already exist in
            the store. */
-        Hash hash(ht), expectedHash(ht);
+        std::optional<Hash> expectedHash;
+        Hash hash(ht);
         std::optional<StorePath> storePath;
         if (args.size() == 2) {
             expectedHash = Hash::parseAny(args[1], ht);
             const auto recursive = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
-            storePath = store->makeFixedOutputPath(recursive, expectedHash, name);
+            storePath = store->makeFixedOutputPath(recursive, *expectedHash, name);
             if (store->isValidPath(*storePath))
-                hash = expectedHash;
+                hash = *expectedHash;
             else
                 storePath.reset();
         }
@@ -200,22 +201,12 @@ static int _main(int argc, char * * argv)
                     tmpFile = unpacked;
             }
 
-            /* FIXME: inefficient; addToStore() will also hash
-               this. */
-            hash = unpack ? hashPath(ht, tmpFile).first : hashFile(ht, tmpFile);
+            const auto method = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
 
-            if (expectedHash != Hash(ht) && expectedHash != hash)
-                throw Error("hash mismatch for '%1%'", uri);
-
-            const auto recursive = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
-
-            /* Copy the file to the Nix store. FIXME: if RemoteStore
-               implemented addToStoreFromDump() and downloadFile()
-               supported a sink, we could stream the download directly
-               into the Nix store. */
-            storePath = store->addToStore(name, tmpFile, recursive, ht);
-
-            assert(*storePath == store->makeFixedOutputPath(recursive, hash, name));
+            auto info = store->addToStoreSlow(name, tmpFile, method, ht, expectedHash);
+            storePath = info.path;
+            assert(info.ca);
+            hash = getContentAddressHash(*info.ca);
         }
 
         stopProgressBar();

src/nix-store/nix-store.cc

@@ -174,10 +174,10 @@ static void opAdd(Strings opFlags, Strings opArgs)
    store. */
 static void opAddFixed(Strings opFlags, Strings opArgs)
 {
-    auto recursive = FileIngestionMethod::Flat;
+    auto method = FileIngestionMethod::Flat;
 
     for (auto & i : opFlags)
-        if (i == "--recursive") recursive = FileIngestionMethod::Recursive;
+        if (i == "--recursive") method = FileIngestionMethod::Recursive;
         else throw UsageError("unknown flag '%1%'", i);
 
     if (opArgs.empty())
@@ -187,7 +187,7 @@ static void opAddFixed(Strings opFlags, Strings opArgs)
     opArgs.pop_front();
 
     for (auto & i : opArgs)
-        cout << fmt("%s\n", store->printStorePath(store->addToStore(std::string(baseNameOf(i)), i, recursive, hashAlgo)));
+        std::cout << fmt("%s\n", store->printStorePath(store->addToStoreSlow(baseNameOf(i), i, method, hashAlgo).path));
 }