* Get garbage collection and cache population to work *properly*.

  Renamed `fstateRefs' to `fstateRequisites'.  The semantics of this
  function is that it returns a list of all paths necessary to realise
  a given expression.  For a derive expression, this is the union of
  requisites of the inputs; for a slice expression, it is the path of
  each element in the slice.  Also included are the paths of the
  expressions themselves.  Optionally, one can also include the
  requisites of successor expressions (to recycle intermediate
  results).

* `nix-switch' now distinguishes between an expression and its normal
  form.  Usually, only the normal form is registered as a root of the
  garbage collector.  With the `--source-root' flag, it will also
  register the original expression as a root.

* `nix-collect-garbage' now has a flag `--keep-successors' which
  causes successors not to be included in the list of garbage paths.

* `nix-collect-garbage' now has a flag `--invert' which will print all
  paths that should *not* be garbage collected.

1 files changed, 10 insertions, 5 deletions

diff --git a/src/nix.cc b/src/nix.cc
index a7bcf72684..68d01f2f87 100644
--- a/src/nix.cc
+++ b/src/nix.cc
@@ -95,18 +95,22 @@ FSId maybeNormalise(const FSId & id, bool normalise)
 /* Perform various sorts of queries. */
 static void opQuery(Strings opFlags, Strings opArgs)
 {
-    enum { qList, qRefs, qGenerators, qExpansion, qGraph 
+    enum { qList, qRequisites, qGenerators, qExpansion, qGraph 
     } query = qList;
     bool normalise = false;
+    bool includeExprs = true;
+    bool includeSuccessors = false;
 
     for (Strings::iterator i = opFlags.begin();
          i != opFlags.end(); i++)
         if (*i == "--list" || *i == "-l") query = qList;
-        else if (*i == "--refs" || *i == "-r") query = qRefs;
+        else if (*i == "--requisites" || *i == "-r") query = qRequisites;
         else if (*i == "--generators" || *i == "-g") query = qGenerators;
         else if (*i == "--expansion" || *i == "-e") query = qExpansion;
         else if (*i == "--graph") query = qGraph;
         else if (*i == "--normalise" || *i == "-n") normalise = true;
+        else if (*i == "--exclude-exprs") includeExprs = false;
+        else if (*i == "--include-successors") includeSuccessors = true;
         else throw UsageError(format("unknown flag `%1%'") % *i);
 
     switch (query) {
@@ -126,13 +130,14 @@ static void opQuery(Strings opFlags, Strings opArgs)
             break;
         }
 
-        case qRefs: {
+        case qRequisites: {
             StringSet paths;
             for (Strings::iterator i = opArgs.begin();
                  i != opArgs.end(); i++)
             {
-                Strings paths2 = fstateRefs(
-                    maybeNormalise(argToId(*i), normalise));
+                Strings paths2 = fstateRequisites(
+                    maybeNormalise(argToId(*i), normalise),
+                    includeExprs, includeSuccessors);
                 paths.insert(paths2.begin(), paths2.end());
             }
             for (StringSet::iterator i = paths.begin();