Fix S3BinaryCacheStore

It failed with

   AWS error uploading ‘6gaxphsyhg66mz0a00qghf9nqf7majs2.ls.xz’: Unable to parse ExceptionName: MissingContentLength Message: You must provide the Content-Length HTTP header.

possibly because the istringstream_nocopy introduced in
0d2ebb4373e509521f27a6e8f16bfd39d05b2188 doesn't supply the seek
method that the AWS library expects. So bring back the old version,
but only for S3BinaryCacheStore.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index 1bc8576a8aef..3c5101f0009a 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -18,6 +18,15 @@
 
 namespace nix {
 
+struct istringstream_nocopy : public std::stringstream
+{
+    istringstream_nocopy(const std::string & s)
+    {
+        rdbuf()->pubsetbuf(
+            (char *) s.data(), s.size());
+    }
+};
+
 struct S3Error : public Error
 {
     Aws::S3::S3Errors err;