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https://github.com/privatevoid-net/nix-super.git
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6baa2c4420
simplifies stuff. * The format of Nix expressions and the database schema changed because of this, so it's best to delete old Nix installations.
61 lines
1.5 KiB
C++
61 lines
1.5 KiB
C++
#include <string>
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#include "util.hh"
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/* dumpPath creates a Nix archive of the specified path. The format
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is as follows:
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IF path points to a REGULAR FILE:
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dump(path) = attrs(
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[ ("type", "regular")
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, ("contents", contents(path))
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])
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IF path points to a DIRECTORY:
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dump(path) = attrs(
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[ ("type", "directory")
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, ("entries", concat(map(f, sort(entries(path)))))
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])
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where f(fn) = attrs(
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[ ("name", fn)
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, ("file", dump(path + "/" + fn))
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])
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where:
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attrs(as) = concat(map(attr, as)) + encN(0)
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attrs((a, b)) = encS(a) + encS(b)
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encS(s) = encN(len(s)) + s + (padding until next 64-bit boundary)
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encN(n) = 64-bit little-endian encoding of n.
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contents(path) = the contents of a regular file.
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sort(strings) = lexicographic sort by 8-bit value (strcmp).
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entries(path) = the entries of a directory, without `.' and
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`..'.
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`+' denotes string concatenation. */
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struct DumpSink
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{
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virtual void operator () (const unsigned char * data, unsigned int len) = 0;
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};
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void dumpPath(const Path & path, DumpSink & sink);
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struct RestoreSource
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{
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/* The callee should store exactly *len bytes in the buffer
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pointed to by data. It should block if that much data is not
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yet available, or throw an error if it is not going to be
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available. */
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virtual void operator () (unsigned char * data, unsigned int len) = 0;
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};
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void restorePath(const Path & path, RestoreSource & source);
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