Factor out commonality between nix-prefetch-url and nix-store --add-f…

…ixed

src/libstore/content-address.cc

@@ -82,4 +82,16 @@ 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 +222,37 @@ 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 hash = method == FileIngestionMethod::Recursive
+ ? hashPath(hashAlgo, srcPath).first
+ : hashFile(hashAlgo, srcPath);
+
+ if (expectedCAHash && expectedCAHash != hash)
+ throw Error("hash mismatch for '%s'", srcPath);
+
+ auto [narHash, narSize] = hashPath(htSHA256, 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

@@ -450,6 +450,13 @@ 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

@@ -10,7 +10,6 @@
 #include "../nix/legacy.hh"
 #include "progress-bar.hh"
 #include "tarfile.hh"
-#include "archive.hh"
 
 #include <iostream>
 
@@ -154,14 +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, expectedHash(ht);
+ std::optional<Hash> expectedHash;
+ Hash hash;
  std::optional<StorePath> storePath;
  if (args.size() == 2) {
  expectedHash = Hash(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();
  }
@@ -201,28 +201,12 @@ static int _main(int argc, char * * argv)
  tmpFile = unpacked;
  }
 
- /* FIXME: inefficient: we're reading/hashing 'tmpFile'
- three times. */
- auto [narHash, narSize] = hashPath(htSHA256, tmpFile);
+ const auto method = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
 
- hash = unpack ? hashPath(ht, tmpFile).first : hashFile(ht, tmpFile);
-
- if (expectedHash != Hash(ht) && expectedHash != hash)
- throw Error("hash mismatch for '%1%'", uri);
-
- const auto recursive = unpack ? FileIngestionMethod::Recursive : FileIngestionMethod::Flat;
-
- storePath = store->makeFixedOutputPath(recursive, hash, name);
-
- /* Copy the file to the Nix store. */
- ValidPathInfo info(*storePath);
- info.narHash = narHash;
- info.narSize = narSize;
- info.ca = FixedOutputHash { .method = recursive, .hash = hash };
- auto source = sinkToSource([&](Sink & sink) {
- dumpPath(tmpFile, sink);
- });
- store->addToStore(info, *source);
+ 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

@@ -186,23 +186,8 @@ static void opAddFixed(Strings opFlags, Strings opArgs)
  HashType hashAlgo = parseHashType(opArgs.front());
  opArgs.pop_front();
 
- for (auto & i : opArgs) {
- auto hash = method == FileIngestionMethod::Recursive
- ? hashPath(hashAlgo, i).first
- : hashFile(hashAlgo, i);
- auto [narHash, narSize] = hashPath(htSHA256, i);
- ValidPathInfo info(store->makeFixedOutputPath(method, hash, baseNameOf(i)));
- info.narHash = narHash;
- info.narSize = narSize;
- info.ca = FixedOutputHash { .method = method, .hash = hash };
-
- auto source = sinkToSource([&](Sink & sink) {
- dumpPath(i, sink);
- });
- store->addToStore(info, *source);
-
- std::cout << fmt("%s\n", store->printStorePath(info.path));
- }
+ for (auto & i : opArgs)
+ std::cout << fmt("%s\n", store->printStorePath(store->addToStoreSlow(baseNameOf(i), i, method, hashAlgo).path));
 }