package fetching: support .tar.zst archives

Author: dweiller

src/Package/Fetch.zig

@@ -752,12 +752,14 @@ const FileType = enum {
     tar,
     @"tar.gz",
     @"tar.xz",
+    @"tar.zst",
     git_pack,
 
     fn fromPath(file_path: []const u8) ?FileType {
         if (ascii.endsWithIgnoreCase(file_path, ".tar")) return .tar;
         if (ascii.endsWithIgnoreCase(file_path, ".tar.gz")) return .@"tar.gz";
         if (ascii.endsWithIgnoreCase(file_path, ".tar.xz")) return .@"tar.xz";
+        if (ascii.endsWithIgnoreCase(file_path, ".tar.zst")) return .@"tar.zst";
         return null;
     }
 
@@ -1015,6 +1017,7 @@ fn unpackResource(
         .tar => try unpackTarball(f, tmp_directory.handle, resource.reader()),
         .@"tar.gz" => try unpackTarballCompressed(f, tmp_directory.handle, resource, std.compress.gzip),
         .@"tar.xz" => try unpackTarballCompressed(f, tmp_directory.handle, resource, std.compress.xz),
+        .@"tar.zst" => try unpackTarballCompressed(f, tmp_directory.handle, resource, ZstdWrapper),
         .git_pack => unpackGitPack(f, tmp_directory.handle, resource) catch |err| switch (err) {
             error.FetchFailed => return error.FetchFailed,
             error.OutOfMemory => return error.OutOfMemory,
@@ -1026,6 +1029,18 @@ fn unpackResource(
     }
 }
 
+// due to slight differences in the API of std.compress.(gzip|xz) and std.compress.zstd, zstd is
+// wrapped for generic use in unpackTarballCompressed: see github.com/ziglang/zig/issues/14739
+const ZstdWrapper = struct {
+    fn DecompressType(comptime T: type) type {
+        return error{}!std.compress.zstd.DecompressStream(T, .{});
+    }
+
+    fn decompress(allocator: Allocator, reader: anytype) DecompressType(@TypeOf(reader)) {
+        return std.compress.zstd.decompressStream(allocator, reader);
+    }
+};
+
 fn unpackTarballCompressed(
     f: *Fetch,
     out_dir: fs.Dir,