From 863dcff6c5ffc163010ec1f9e6819bb9aaaadc29 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Wed, 19 Jan 2005 11:16:11 +0000
Subject: * Started removing closure store expressions, i.e., the explicit  
 representation of closures as ATerms in the Nix store.  Instead, the   file
 system pointer graph is now stored in the Nix database.  This   has many
 advantages:

  - It greatly simplifies the implementation (we can drop the notion
    of `successors', and so on).

  - It makes registering roots for the garbage collector much easier.
    Instead of specifying the closure expression as a root, you can
    simply specify the store path that must be retained as a root.
    This could not be done previously, since there was no way to find
    the closure store expression containing a given store path.

  - Better traceability: it is now possible to query what paths are
    referenced by a path, and what paths refer to a path.
---
 src/libstore/misc.cc | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

(limited to 'src/libstore/misc.cc')

diff --git a/src/libstore/misc.cc b/src/libstore/misc.cc
index 6dc054fb43d7..24a522c1ed44 100644
--- a/src/libstore/misc.cc
+++ b/src/libstore/misc.cc
@@ -1,16 +1,32 @@
 #include "normalise.hh"
 
 
-StoreExpr storeExprFromPath(const Path & path)
+Derivation derivationFromPath(const Path & drvPath)
 {
-    assertStorePath(path);
-    ensurePath(path);
-    ATerm t = ATreadFromNamedFile(path.c_str());
-    if (!t) throw Error(format("cannot read aterm from `%1%'") % path);
-    return parseStoreExpr(t);
+    assertStorePath(drvPath);
+    ensurePath(drvPath);
+    ATerm t = ATreadFromNamedFile(drvPath.c_str());
+    if (!t) throw Error(format("cannot read aterm from `%1%'") % drvPath);
+    return parseDerivation(t);
 }
 
 
+void computeFSClosure(const Path & storePath,
+    PathSet & paths)
+{
+    if (paths.find(storePath) != paths.end()) return;
+    paths.insert(storePath);
+
+    PathSet references;
+    queryReferences(storePath, references);
+
+    for (PathSet::iterator i = references.begin();
+         i != references.end(); ++i)
+        computeFSClosure(*i, paths);
+}
+
+
+#if 0
 PathSet storeExprRoots(const Path & nePath)
 {
     PathSet paths;
@@ -71,3 +87,4 @@ PathSet storeExprRequisites(const Path & nePath,
         paths, doneSet);
     return paths;
 }
+#endif
-- 
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