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#include "db.hh"
#include "hash.hh"
#include "util.hh"
#include "local-store.hh"
#include "globals.hh"
#include "pathlocks.hh"
#include "config.h"
#include <iostream>
namespace nix {
Hash parseHashField(const Path & path, const string & s);
/* Upgrade from schema 4 (Nix 0.11) to schema 5 (Nix >= 0.12). The
old schema uses Berkeley DB, the new one stores store path
meta-information in files. */
void LocalStore::upgradeStore12()
{
#if OLD_DB_COMPAT
#ifdef __CYGWIN__
/* Cygwin can't upgrade a read lock to a write lock... */
lockFile(globalLock, ltNone, true);
#endif
if (!lockFile(globalLock, ltWrite, false)) {
printMsg(lvlError, "waiting for exclusive access to the Nix store...");
lockFile(globalLock, ltWrite, true);
}
printMsg(lvlError, "upgrading Nix store to new schema (this may take a while)...");
if (getSchema() >= nixSchemaVersion) return; /* somebody else beat us to it */
/* Open the old Nix database and tables. */
Database nixDB;
nixDB.open(nixDBPath);
/* dbValidPaths :: Path -> ()
The existence of a key $p$ indicates that path $p$ is valid
(that is, produced by a succesful build). */
TableId dbValidPaths = nixDB.openTable("validpaths");
/* dbReferences :: Path -> [Path]
This table lists the outgoing file system references for each
output path that has been built by a Nix derivation. These are
found by scanning the path for the hash components of input
paths. */
TableId dbReferences = nixDB.openTable("references");
/* dbReferrers :: Path -> Path
This table is just the reverse mapping of dbReferences. This
table can have duplicate keys, each corresponding value
denoting a single referrer. */
// Not needed for conversion: it's just the inverse of
// references.
// TableId dbReferrers = nixDB.openTable("referrers");
/* dbDerivers :: Path -> [Path]
This table lists the derivation used to build a path. There
can only be multiple such paths for fixed-output derivations
(i.e., derivations specifying an expected hash). */
TableId dbDerivers = nixDB.openTable("derivers");
Paths paths;
nixDB.enumTable(noTxn, dbValidPaths, paths);
for (Paths::iterator i = paths.begin(); i != paths.end(); ++i) {
ValidPathInfo info;
info.path = *i;
Paths references;
nixDB.queryStrings(noTxn, dbReferences, *i, references);
info.references.insert(references.begin(), references.end());
string s;
nixDB.queryString(noTxn, dbValidPaths, *i, s);
info.hash = parseHashField(*i, s);
nixDB.queryString(noTxn, dbDerivers, *i, info.deriver);
registerValidPath(info, true);
std::cerr << ".";
}
std::cerr << std::endl;
writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str());
lockFile(globalLock, ltRead, true);
#else
throw Error(
"Your Nix store has a database in Berkeley DB format. To convert\n"
"to the new format, please compile Nix with Berkeley DB support.");
#endif
}
}
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