about summary refs log tree commit diff
path: root/src/libstore/binary-cache-store.hh
diff options
context:
space:
mode:
authorEelco Dolstra <edolstra@gmail.com>2018-03-27T21·12+0200
committerEelco Dolstra <edolstra@gmail.com>2018-05-30T11·34+0200
commit08ec757726e5ef47e71bf16ed0b252b288bcf0f3 (patch)
tree7a9fc6b077d694620052522ae45cc274b09e0096 /src/libstore/binary-cache-store.hh
parent81ea8bd5ceb3dcae6af0b79c81a39ecbf2ba97a8 (diff)
Make LocalBinaryCacheStore::narFromPath() run in constant memory
This reduces memory consumption of

  nix copy --from file://... --to ~/my-nix /nix/store/95cwv4q54dc6giaqv6q6p4r02ia2km35-blender-2.79

from 514 MiB to 18 MiB for an uncompressed binary cache, and from 192
MiB to 53 MiB for a bzipped binary cache. It may also be faster
because fetching can happen concurrently with decompression/writing.

Continuation of 48662d151bdf4a38670897beacea9d1bd750376a.

Issue https://github.com/NixOS/nix/issues/1681.
Diffstat (limited to 'src/libstore/binary-cache-store.hh')
-rw-r--r--src/libstore/binary-cache-store.hh14
1 files changed, 11 insertions, 3 deletions
diff --git a/src/libstore/binary-cache-store.hh b/src/libstore/binary-cache-store.hh
index fcde666beec6..6bc83fc50ca1 100644
--- a/src/libstore/binary-cache-store.hh
+++ b/src/libstore/binary-cache-store.hh
@@ -38,10 +38,16 @@ public:
         const std::string & data,
         const std::string & mimeType) = 0;
 
-    /* Return the contents of the specified file, or null if it
-       doesn't exist. */
+    /* Note: subclasses must implement at least one of the two
+       following getFile() methods. */
+
+    /* Dump the contents of the specified file to a sink. */
+    virtual void getFile(const std::string & path, Sink & sink);
+
+    /* Fetch the specified file and call the specified callback with
+       the result. A subclass may implement this asynchronously. */
     virtual void getFile(const std::string & path,
-        Callback<std::shared_ptr<std::string>> callback) = 0;
+        Callback<std::shared_ptr<std::string>> callback);
 
     std::shared_ptr<std::string> getFile(const std::string & path);
 
@@ -129,4 +135,6 @@ public:
 
 };
 
+MakeError(NoSuchBinaryCacheFile, Error);
+
 }