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* Enclose most operations that update the database in transactions.

Browse source 
* Open all database tables (Db objects) at initialisation time, not
  every time they are used.  This is necessary because tables have to
  outlive all transactions that refer to them.
This commit is contained in:
Eelco Dolstra 2003-07-31 16:05:35 +00:00
parent 177a7782ae
commit 06d3d7355d
6 changed files with 145 additions and 96 deletions
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57
src/store.cc
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@ -32,6 +32,8 @@ struct CopySource : RestoreSource
void copyPath(string src, string dst)
{
debug(format("copying `%1%' to `%2%'") % src % dst);
/* Unfortunately C++ doesn't support coprocedures, so we have no
nice way to chain CopySink and CopySource together. Instead we
fork off a child to run the sink. (Fork-less platforms should
@ -96,54 +98,69 @@ void registerSubstitute(const FSId & srcId, const FSId & subId)
/* For now, accept only one substitute per id. */
Strings subs;
subs.push_back(subId);
nixDB.setStrings(noTxn, dbSubstitutes, srcId, subs);
Transaction txn(nixDB);
nixDB.setStrings(txn, dbSubstitutes, srcId, subs);
txn.commit();
}
void registerPath(const string & _path, const FSId & id)
{
string path(canonPath(_path));
Transaction txn(nixDB);
nixDB.setString(noTxn, dbPath2Id, path, id);
debug(format("registering path `%1%' with id %2%")
% path % (string) id);
string oldId;
if (nixDB.queryString(txn, dbPath2Id, path, oldId)) {
txn.abort();
if (id != parseHash(oldId))
throw Error(format("path `%1%' already contains id %2%")
% path % oldId);
return;
}
nixDB.setString(txn, dbPath2Id, path, id);
Strings paths;
nixDB.queryStrings(noTxn, dbId2Paths, id, paths); /* non-existence = ok */
for (Strings::iterator it = paths.begin();
it != paths.end(); it++)
if (*it == path) return;
nixDB.queryStrings(txn, dbId2Paths, id, paths); /* non-existence = ok */
paths.push_back(path);
nixDB.setStrings(noTxn, dbId2Paths, id, paths);
nixDB.setStrings(txn, dbId2Paths, id, paths);
txn.commit();
}
void unregisterPath(const string & _path)
{
string path(canonPath(_path));
Transaction txn(nixDB);
debug(format("unregistering path `%1%'") % path);
string _id;
if (!nixDB.queryString(noTxn, dbPath2Id, path, _id)) return;
if (!nixDB.queryString(txn, dbPath2Id, path, _id)) {
txn.abort();
return;
}
FSId id(parseHash(_id));
nixDB.delPair(noTxn, dbPath2Id, path);
nixDB.delPair(txn, dbPath2Id, path);
/* begin transaction */
Strings paths, paths2;
nixDB.queryStrings(noTxn, dbId2Paths, id, paths); /* non-existence = ok */
nixDB.queryStrings(txn, dbId2Paths, id, paths); /* non-existence = ok */
bool changed = false;
for (Strings::iterator it = paths.begin();
it != paths.end(); it++)
if (*it != path) paths2.push_back(*it); else changed = true;
if (*it != path) paths2.push_back(*it);
if (changed)
nixDB.setStrings(noTxn, dbId2Paths, id, paths2);
/* end transaction */
nixDB.setStrings(txn, dbId2Paths, id, paths2);
txn.commit();
}
@ -230,6 +247,8 @@ string expandId(const FSId & id, const string & target,
void addToStore(string srcPath, string & dstPath, FSId & id,
bool deterministicName)
{
debug(format("adding `%1%' to the store") % srcPath);
srcPath = absPath(srcPath);
id = hashPath(srcPath);