Drop remaining uses of external "tar"

Also, fetchGit now runs in O(1) memory since we pipe the output of
'git archive' directly into unpackTarball() (rather than first reading
it all into memory).

1 files changed, 21 insertions, 1 deletions

diff --git a/src/libutil/tarfile.cc b/src/libutil/tarfile.cc
index ae6d512bd..f7d3ad417 100644
--- a/src/libutil/tarfile.cc
+++ b/src/libutil/tarfile.cc
@@ -1,4 +1,5 @@
 #include "rust-ffi.hh"
+#include "compression.hh"
 
 extern "C" {
     rust::CBox2<rust::Result<std::tuple<>>> unpack_tarfile(rust::Source source, rust::StringSlice dest_dir);
@@ -6,9 +7,28 @@ extern "C" {
 
 namespace nix {
 
-void unpackTarfile(Source & source, Path destDir)
+void unpackTarfile(Source & source, const Path & destDir)
 {
     unpack_tarfile(source, destDir).use()->unwrap();
 }
 
+void unpackTarfile(const Path & tarFile, const Path & destDir,
+    std::optional<std::string> baseName)
+{
+    if (!baseName) baseName = baseNameOf(tarFile);
+
+    auto source = sinkToSource([&](Sink & sink) {
+        // FIXME: look at first few bytes to determine compression type.
+        auto decompressor =
+            // FIXME: add .gz support
+            hasSuffix(*baseName, ".bz2") ? makeDecompressionSink("bzip2", sink) :
+            hasSuffix(*baseName, ".xz") ? makeDecompressionSink("xz", sink) :
+            makeDecompressionSink("none", sink);
+        readFile(tarFile, *decompressor);
+        decompressor->finish();
+    });
+
+    unpackTarfile(*source, destDir);
+}
+
 }