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#pragma once
///@file
#include "generator.hh"
#include "types.hh"
#include "serialise.hh"
#include "file-system.hh"
namespace nix {
/**
* dumpPath creates a Nix archive of the specified path.
*
* @param path the file system data to dump. Dumping is recursive so if
* this is a directory we dump it and all its children.
*
* @param [out] sink The serialised archive is fed into this sink.
*
* @param filter Can be used to skip certain files.
*
* The format is as follows:
*
* ```
* IF path points to a REGULAR FILE:
* dump(path) = attrs(
* [ ("type", "regular")
* , ("contents", contents(path))
* ])
*
* IF path points to a DIRECTORY:
* dump(path) = attrs(
* [ ("type", "directory")
* , ("entries", concat(map(f, sort(entries(path)))))
* ])
* where f(fn) = attrs(
* [ ("name", fn)
* , ("file", dump(path + "/" + fn))
* ])
*
* where:
*
* attrs(as) = concat(map(attr, as)) + encN(0)
* attrs((a, b)) = encS(a) + encS(b)
*
* encS(s) = encN(len(s)) + s + (padding until next 64-bit boundary)
*
* encN(n) = 64-bit little-endian encoding of n.
*
* contents(path) = the contents of a regular file.
*
* sort(strings) = lexicographic sort by 8-bit value (strcmp).
*
* entries(path) = the entries of a directory, without `.` and
* `..`.
*
* `+` denotes string concatenation.
* ```
*/
WireFormatGenerator dumpPath(Path path,
PathFilter & filter = defaultPathFilter);
/**
* Same as dumpPath(), but returns the last modified date of the path.
*/
WireFormatGenerator dumpPathAndGetMtime(Path path, time_t & mtime,
PathFilter & filter = defaultPathFilter);
/**
* Dump an archive with a single file with these contents.
*
* @param s Contents of the file.
*/
WireFormatGenerator dumpString(std::string_view s);
/**
* \todo Fix this API, it sucks.
* A visitor for NAR parsing that performs filesystem (or virtual-filesystem)
* actions to restore a NAR.
*
* Methods of this may arbitrarily fail due to filename collisions.
*/
struct NARParseVisitor
{
/**
* A type-erased file handle specific to this particular NARParseVisitor.
*/
struct FileHandle
{
FileHandle() {}
FileHandle(FileHandle const &) = delete;
FileHandle & operator=(FileHandle &) = delete;
/** Puts one block of data into the file */
virtual void receiveContents(std::string_view data) { }
/**
* Explicitly closes the file. Further operations may throw an assert.
* This exists so that closing can fail and throw an exception without doing so in a destructor.
*/
virtual void close() { }
virtual ~FileHandle() = default;
};
virtual void createDirectory(const Path & path) { }
/**
* Creates a regular file in the extraction output with the given size and executable flag.
* The size is guaranteed to be the true size of the file.
*/
[[nodiscard]]
virtual std::unique_ptr<FileHandle> createRegularFile(const Path & path, uint64_t size, bool executable)
{
return std::make_unique<FileHandle>();
}
virtual void createSymlink(const Path & path, const std::string & target) { }
};
namespace nar {
struct MetadataString;
struct MetadataRaw;
struct File;
struct Symlink;
struct Directory;
using Entry = std::variant<MetadataString, MetadataRaw, File, Symlink, Directory>;
struct MetadataString
{
std::string_view data;
};
struct MetadataRaw
{
Bytes raw;
};
struct File
{
const Path & path;
bool executable;
uint64_t size;
Generator<Bytes> contents;
};
struct Symlink
{
const Path & path;
const Path & target;
};
struct Directory
{
const Path & path;
Generator<Entry> contents;
};
Generator<Entry> parse(Source & source);
}
WireFormatGenerator parseAndCopyDump(NARParseVisitor & sink, Source & source);
void parseDump(NARParseVisitor & sink, Source & source);
void restorePath(const Path & path, Source & source);
/**
* Read a NAR from 'source' and return it as a generator.
*/
WireFormatGenerator copyNAR(Source & source);
inline constexpr std::string_view narVersionMagic1 = "nix-archive-1";
inline constexpr std::string_view caseHackSuffix = "~nix~case~hack~";
}
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