forked from lix-project/lix
* Revived the old "nix-store --delete" operation that deletes the
specified paths from the Nix store. However, this operation is safe: it refuses to delete anything that the garbage collector wouldn't delete.
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3c5619c7e4
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4b9e7f59ca
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@ -303,8 +303,8 @@ static Paths topoSort(const PathSet & paths)
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}
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void collectGarbage(GCAction action, PathSet & result,
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unsigned long long & bytesFreed)
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void collectGarbage(GCAction action, const PathSet & pathsToDelete,
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PathSet & result, unsigned long long & bytesFreed)
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{
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result.clear();
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bytesFreed = 0;
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@ -398,17 +398,26 @@ void collectGarbage(GCAction action, PathSet & result,
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/* Read the Nix store directory to find all currently existing
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paths. */
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Paths storePaths = readDirectory(nixStore);
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PathSet storePaths2;
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for (Paths::iterator i = storePaths.begin(); i != storePaths.end(); ++i)
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storePaths2.insert(canonPath(nixStore + "/" + *i));
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PathSet storePathSet;
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if (action != gcDeleteSpecific) {
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Paths entries = readDirectory(nixStore);
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for (Paths::iterator i = entries.begin(); i != entries.end(); ++i)
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storePathSet.insert(canonPath(nixStore + "/" + *i));
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} else {
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for (PathSet::iterator i = pathsToDelete.begin();
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i != pathsToDelete.end(); ++i)
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{
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assertStorePath(*i);
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storePathSet.insert(*i);
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}
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}
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/* Topologically sort them under the `referrers' relation. That
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is, a < b iff a is in referrers(b). This gives us the order in
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which things can be deleted safely. */
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/* !!! when we have multiple output paths per derivation, this
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will not work anymore because we get cycles. */
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storePaths = topoSort(storePaths2);
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Paths storePaths = topoSort(storePathSet);
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/* Try to delete store paths in the topologically sorted order. */
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for (Paths::iterator i = storePaths.begin(); i != storePaths.end(); ++i) {
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@ -416,6 +425,8 @@ void collectGarbage(GCAction action, PathSet & result,
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debug(format("considering deletion of `%1%'") % *i);
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if (livePaths.find(*i) != livePaths.end()) {
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if (action == gcDeleteSpecific)
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throw Error(format("cannot delete path `%1%' since it is still alive") % *i);
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debug(format("live path `%1%'") % *i);
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continue;
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}
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@ -430,7 +441,7 @@ void collectGarbage(GCAction action, PathSet & result,
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AutoCloseFD fdLock;
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if (action == gcDeleteDead) {
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if (action == gcDeleteDead || action == gcDeleteSpecific) {
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/* Only delete a lock file if we can acquire a write lock
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on it. That means that it's either stale, or the
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@ -10,6 +10,7 @@ typedef enum {
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gcReturnLive,
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gcReturnDead,
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gcDeleteDead,
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gcDeleteSpecific,
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} GCAction;
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/* If `action' is set to `gcReturnRoots', find and return the set of
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@ -19,8 +20,8 @@ typedef enum {
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closure of) the roots. If `action' is `gcReturnDead', return the
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set of paths not reachable from the roots. If `action' is
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`gcDeleteDead', actually delete the latter set. */
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void collectGarbage(GCAction action, PathSet & result,
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unsigned long long & bytesFreed);
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void collectGarbage(GCAction action, const PathSet & pathsToDelete,
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PathSet & result, unsigned long long & bytesFreed);
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/* Register a temporary GC root. This root will automatically
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disappear when this process exits. WARNING: this function should
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@ -7,6 +7,7 @@ Operations:
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--realise / -r: ensure path validity; if a derivation, ensure that
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validity of the outputs
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--add / -A: copy a path to the Nix store
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--delete: safely delete paths from the Nix store
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--query / -q: query information
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--register-substitutes: register a substitute expression (dangerous!)
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@ -518,7 +518,7 @@ static void opGC(Strings opFlags, Strings opArgs)
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PathSet result;
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PrintFreed freed(action == gcDeleteDead);
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collectGarbage(action, result, freed.bytesFreed);
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collectGarbage(action, PathSet(), result, freed.bytesFreed);
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if (action != gcDeleteDead) {
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for (PathSet::iterator i = result.begin(); i != result.end(); ++i)
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@ -527,6 +527,25 @@ static void opGC(Strings opFlags, Strings opArgs)
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}
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/* Remove paths from the Nix store if possible (i.e., if they do not
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have any remaining referrers and are not reachable from any GC
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roots). */
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static void opDelete(Strings opFlags, Strings opArgs)
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{
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if (!opFlags.empty()) throw UsageError("unknown flag");
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PathSet pathsToDelete;
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for (Strings::iterator i = opArgs.begin();
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i != opArgs.end(); ++i)
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pathsToDelete.insert(fixPath(*i));
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PathSet dummy;
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PrintFreed freed(true);
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collectGarbage(gcDeleteSpecific, pathsToDelete,
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dummy, freed.bytesFreed);
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}
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/* A sink that writes dump output to stdout. */
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struct StdoutSink : DumpSink
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{
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@ -621,6 +640,8 @@ void run(Strings args)
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op = opAddFixed;
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else if (arg == "--print-fixed-path")
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op = opPrintFixedPath;
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else if (arg == "--delete")
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op = opDelete;
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else if (arg == "--query" || arg == "-q")
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op = opQuery;
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else if (arg == "--register-substitutes")
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