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* Reverse mappings for the successor and substitute mappings.

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This commit is contained in:
Eelco Dolstra 2003-10-10 14:46:28 +00:00
parent 1eb4da156c
commit d3d5e77810
6 changed files with 68 additions and 27 deletions
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56
src/store.cc
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@ -81,26 +81,50 @@ void copyPath(const Path & src, const Path & dst)
}
void registerSuccessor(const Transaction & txn,
const Path & path1, const Path & path2)
{
Path known;
if (nixDB.queryString(txn, dbSuccessors, path1, known) &&
known != path2)
{
throw Error(format(
"the `impossible' happened: expression in path "
"`%1%' appears to have multiple successors "
"(known `%2%', new `%3%'")
% path1 % known % path2);
}
Paths revs;
nixDB.queryStrings(txn, dbSuccessorsRev, path2, revs);
revs.push_back(path1);
nixDB.setString(txn, dbSuccessors, path1, path2);
nixDB.setStrings(txn, dbSuccessorsRev, path2, revs);
}
void registerSubstitute(const Path & srcPath, const Path & subPath)
{
#if 0
Strings subs;
queryListDB(nixDB, dbSubstitutes, srcId, subs); /* non-existence = ok */
for (Strings::iterator it = subs.begin(); it != subs.end(); it++)
if (parseHash(*it) == subId) return;
subs.push_back(subId);
setListDB(nixDB, dbSubstitutes, srcId, subs);
#endif
/* For now, accept only one substitute per id. */
Strings subs;
subs.push_back(subPath);
Transaction txn(nixDB);
Paths subs;
nixDB.queryStrings(txn, dbSubstitutes, srcPath, subs);
if (find(subs.begin(), subs.end(), subPath) != subs.end()) {
/* Nothing to do if the substitute is already known. */
txn.abort();
return;
}
subs.push_front(subPath); /* new substitutes take precedence */
Paths revs;
nixDB.queryStrings(txn, dbSubstitutesRev, subPath, revs);
revs.push_back(srcPath);
nixDB.setStrings(txn, dbSubstitutes, srcPath, subs);
nixDB.setStrings(txn, dbSubstitutesRev, subPath, revs);
txn.commit();
}