forked from lix-project/lix
* In normaliseFState(), wrap registration of the output paths and the
normal form in a single transaction to ensure that if we crash, either everything is registered or nothing is. This is for recoverability: unregistered paths in the store can be deleted arbitrarily, while registered paths can only be deleted by running the garbage collector.
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@ -44,7 +44,10 @@ FSId writeTerm(ATerm t, const string & suffix, FSId id)
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// debug(format("written term %1% = %2%") % (string) id %
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// printTerm(t));
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registerPath(path, id);
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Transaction txn(nixDB);
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registerPath(txn, path, id);
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txn.commit();
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return id;
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}
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@ -240,13 +240,15 @@ static void opSuccessor(Strings opFlags, Strings opArgs)
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if (!opFlags.empty()) throw UsageError("unknown flag");
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if (opArgs.size() % 2) throw UsageError("expecting even number of arguments");
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Transaction txn(nixDB); /* !!! this could be a big transaction */
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for (Strings::iterator i = opArgs.begin();
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i != opArgs.end(); )
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{
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FSId id1 = parseHash(*i++);
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FSId id2 = parseHash(*i++);
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registerSuccessor(id1, id2);
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registerSuccessor(txn, id1, id2);
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}
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txn.commit();
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}
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@ -8,19 +8,10 @@
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#include "globals.hh"
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void registerSuccessor(const FSId & id1, const FSId & id2)
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void registerSuccessor(const Transaction & txn,
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const FSId & id1, const FSId & id2)
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{
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Transaction txn(nixDB);
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nixDB.setString(txn, dbSuccessors, id1, id2);
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txn.commit();
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}
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static FSId storeSuccessor(const FSId & id1, ATerm sc)
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{
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FSId id2 = writeTerm(sc, "-s-" + (string) id1);
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registerSuccessor(id1, id2);
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return id2;
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}
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@ -175,8 +166,8 @@ FSId normaliseFState(FSId id, FSIdSet pending)
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} else
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msg(lvlChatty, format("fast build succesful"));
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/* Check whether the output paths were created, and register each
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one. */
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/* Check whether the output paths were created, and grep each
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output path to determine what other paths it references. */
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FSIdSet used;
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for (OutPaths::iterator i = outPaths.begin();
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i != outPaths.end(); i++)
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@ -184,7 +175,6 @@ FSId normaliseFState(FSId id, FSIdSet pending)
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string path = i->first;
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if (!pathExists(path))
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throw Error(format("path `%1%' does not exist") % path);
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registerPath(path, i->second);
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fs.slice.roots.push_back(i->second);
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Strings refs = filterReferences(path, refPaths);
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@ -224,10 +214,27 @@ FSId normaliseFState(FSId id, FSIdSet pending)
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}
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}
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/* Write the normal form. This does not have to occur in the
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transaction below because writing terms is idem-potent. */
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fs.type = FState::fsSlice;
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ATerm nf = unparseFState(fs);
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msg(lvlVomit, format("normal form: %1%") % printTerm(nf));
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return storeSuccessor(id, nf);
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FSId idNF = writeTerm(nf, "-s-" + (string) id);
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/* Register each outpat path, and register the normal form. This
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is wrapped in one database transaction to ensure that if we
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crash, either everything is registered or nothing is. This is
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for recoverability: unregistered paths in the store can be
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deleted arbitrarily, while registered paths can only be deleted
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by running the garbage collector. */
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Transaction txn(nixDB);
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for (OutPaths::iterator i = outPaths.begin();
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i != outPaths.end(); i++)
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registerPath(txn, i->first, i->second);
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registerSuccessor(txn, id, idNF);
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txn.commit();
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return idNF;
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}
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@ -29,7 +29,8 @@ Strings fstateRequisites(const FSId & id,
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FSIds findGenerators(const FSIds & ids);
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/* Register a successor. */
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void registerSuccessor(const FSId & id1, const FSId & id2);
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void registerSuccessor(const Transaction & txn,
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const FSId & id1, const FSId & id2);
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#endif /* !__NORMALISE_H */
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15
src/store.cc
15
src/store.cc
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@ -105,17 +105,16 @@ void registerSubstitute(const FSId & srcId, const FSId & subId)
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}
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void registerPath(const string & _path, const FSId & id)
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void registerPath(const Transaction & txn,
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const string & _path, const FSId & id)
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{
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string path(canonPath(_path));
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Transaction txn(nixDB);
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debug(format("registering path `%1%' with id %2%")
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% path % (string) id);
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string oldId;
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if (nixDB.queryString(txn, dbPath2Id, path, oldId)) {
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txn.abort();
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if (id != parseHash(oldId))
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throw Error(format("path `%1%' already contains id %2%")
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% path % oldId);
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@ -130,8 +129,6 @@ void registerPath(const string & _path, const FSId & id)
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paths.push_back(path);
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nixDB.setStrings(txn, dbId2Paths, id, paths);
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txn.commit();
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}
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@ -215,7 +212,9 @@ string expandId(const FSId & id, const string & target,
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return path;
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else {
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copyPath(path, target);
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registerPath(target, id);
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Transaction txn(nixDB);
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registerPath(txn, target, id);
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txn.commit();
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return target;
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}
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}
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@ -267,7 +266,9 @@ void addToStore(string srcPath, string & dstPath, FSId & id,
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}
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copyPath(srcPath, dstPath);
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registerPath(dstPath, id);
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Transaction txn(nixDB);
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registerPath(txn, dstPath, id);
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txn.commit();
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}
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@ -4,6 +4,7 @@
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#include <string>
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#include "hash.hh"
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#include "db.hh"
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using namespace std;
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@ -20,7 +21,8 @@ void copyPath(string src, string dst);
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void registerSubstitute(const FSId & srcId, const FSId & subId);
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/* Register a path keyed on its id. */
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void registerPath(const string & path, const FSId & id);
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void registerPath(const Transaction & txn,
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const string & path, const FSId & id);
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/* Query the id of a path. */
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bool queryPathId(const string & path, FSId & id);
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