lix/src/nix/copy.cc
Eelco Dolstra bbe97dff8b Make the Store API more type-safe
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
2019-12-10 22:06:05 +01:00

96 lines
2.8 KiB
C++

#include "command.hh"
#include "shared.hh"
#include "store-api.hh"
#include "sync.hh"
#include "thread-pool.hh"
#include <atomic>
using namespace nix;
struct CmdCopy : StorePathsCommand
{
std::string srcUri, dstUri;
CheckSigsFlag checkSigs = CheckSigs;
SubstituteFlag substitute = NoSubstitute;
CmdCopy()
: StorePathsCommand(true)
{
mkFlag()
.longName("from")
.labels({"store-uri"})
.description("URI of the source Nix store")
.dest(&srcUri);
mkFlag()
.longName("to")
.labels({"store-uri"})
.description("URI of the destination Nix store")
.dest(&dstUri);
mkFlag()
.longName("no-check-sigs")
.description("do not require that paths are signed by trusted keys")
.set(&checkSigs, NoCheckSigs);
mkFlag()
.longName("substitute-on-destination")
.shortName('s')
.description("whether to try substitutes on the destination store (only supported by SSH)")
.set(&substitute, Substitute);
}
std::string description() override
{
return "copy paths between Nix stores";
}
Examples examples() override
{
return {
Example{
"To copy Firefox from the local store to a binary cache in file:///tmp/cache:",
"nix copy --to file:///tmp/cache $(type -p firefox)"
},
Example{
"To copy the entire current NixOS system closure to another machine via SSH:",
"nix copy --to ssh://server /run/current-system"
},
Example{
"To copy a closure from another machine via SSH:",
"nix copy --from ssh://server /nix/store/a6cnl93nk1wxnq84brbbwr6hxw9gp2w9-blender-2.79-rc2"
},
#ifdef ENABLE_S3
Example{
"To copy Hello to an S3 binary cache:",
"nix copy --to s3://my-bucket?region=eu-west-1 nixpkgs.hello"
},
Example{
"To copy Hello to an S3-compatible binary cache:",
"nix copy --to s3://my-bucket?region=eu-west-1&endpoint=example.com nixpkgs.hello"
},
#endif
};
}
ref<Store> createStore() override
{
return srcUri.empty() ? StoreCommand::createStore() : openStore(srcUri);
}
void run(ref<Store> srcStore, StorePaths storePaths) override
{
if (srcUri.empty() && dstUri.empty())
throw UsageError("you must pass '--from' and/or '--to'");
ref<Store> dstStore = dstUri.empty() ? openStore() : openStore(dstUri);
copyPaths(srcStore, dstStore, storePathsToSet(storePaths),
NoRepair, checkSigs, substitute);
}
};
static auto r1 = registerCommand<CmdCopy>("copy");