* Merged the no-bdb branch (-r10900:HEAD

https://svn.nixos.org/repos/nix/nix/branches/no-bdb).

configure.ac

@@ -16,7 +16,7 @@ if test "$STABLE" != "1"; then
     fi
 fi
 
-AC_DEFINE_UNQUOTED(NIX_VERSION, ["$VERSION"], [version])
+AC_DEFINE_UNQUOTED(NIX_VERSION, ["$VERSION"], [Nix version.])
 
 AC_PREFIX_DEFAULT(/nix)
 
@@ -54,7 +54,7 @@ case $sys_name in
 esac
 
 AC_ARG_WITH(system, AC_HELP_STRING([--with-system=SYSTEM],
-  [platform identifier (e.g., `i686-linux')]),
+  [Platform identifier (e.g., `i686-linux').]),
   system=$withval, system="${machine_name}-${sys_name}")
 AC_MSG_RESULT($system)
 AC_SUBST(system)
@@ -94,7 +94,7 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <iostream>
 using namespace std;
 static char buf[1024];]],
     [[cerr.rdbuf()->pubsetbuf(buf, sizeof(buf));]])],
-    [AC_MSG_RESULT(yes) AC_DEFINE(HAVE_PUBSETBUF, 1, [whether pubsetbuf is available])],
+    [AC_MSG_RESULT(yes) AC_DEFINE(HAVE_PUBSETBUF, 1, [Whether pubsetbuf is available.])],
     AC_MSG_RESULT(no))
 AC_LANG_POP(C++)
 
@@ -177,8 +177,13 @@ AC_ARG_WITH(store-dir, AC_HELP_STRING([--with-store-dir=PATH],
   storedir=$withval, storedir='${prefix}/store')
 AC_SUBST(storedir)
 
+AC_ARG_ENABLE(old-db-compat, AC_HELP_STRING([--disable-old-db-compat],
+  [disable support for converting from old Berkeley DB-based Nix stores]),
+  old_db_compat=$enableval, old_db_compat=yes)
+AM_CONDITIONAL(OLD_DB_COMPAT, test "$old_db_compat" = "yes")
+
 AC_ARG_WITH(bdb, AC_HELP_STRING([--with-bdb=PATH],
-  [prefix of Berkeley DB]),
+  [prefix of Berkeley DB (for Nix <= 0.11 compatibility)]),
   bdb=$withval, bdb=)
 AM_CONDITIONAL(HAVE_BDB, test -n "$bdb")
 if test -z "$bdb"; then
@@ -188,6 +193,12 @@ else
   bdb_lib="-L$bdb/lib -ldb_cxx"
   bdb_include="-I$bdb/include"
 fi
+if test "$old_db_compat" = "no"; then
+  bdb_lib=
+  bdb_include=
+else
+  AC_DEFINE(OLD_DB_COMPAT, 1, [Whether to support converting from old Berkeley DB-based Nix stores.])
+fi
 AC_SUBST(bdb_lib)
 AC_SUBST(bdb_include)
 
@@ -216,7 +227,7 @@ if test -n "$openssl"; then
   LDFLAGS="-L$openssl/lib -lcrypto $LDFLAGS"
   CFLAGS="-I$openssl/include $CFLAGS"
   CXXFLAGS="-I$openssl/include $CXXFLAGS"
-  AC_DEFINE(HAVE_OPENSSL, 1, [whether to use OpenSSL])
+  AC_DEFINE(HAVE_OPENSSL, 1, [Whether to use OpenSSL.])
 fi
 
 AC_ARG_WITH(bzip2, AC_HELP_STRING([--with-bzip2=PATH],

externals/Makefile.am

@@ -2,6 +2,8 @@
 
 DB = db-4.5.20
 
+if OLD_DB_COMPAT
+
 $(DB).tar.gz:
 	@echo "Nix requires Berkeley DB to build."
 	@echo "Please download version 4.5.20 from"
@@ -32,6 +34,12 @@ build-db: have-db
 	touch build-db
 endif
 
+else
+
+build-db:
+
+endif
+
 
 # CWI ATerm
 

src/libstore/Makefile.am

@@ -1,13 +1,14 @@
 pkglib_LTLIBRARIES = libstore.la
 
 libstore_la_SOURCES = \
- store-api.cc local-store.cc remote-store.cc derivations.cc build.cc misc.cc \
+  store-api.cc local-store.cc remote-store.cc derivations.cc build.cc misc.cc \
- globals.cc db.cc references.cc pathlocks.cc gc.cc 
+  globals.cc db.cc references.cc pathlocks.cc gc.cc upgrade-schema.cc \
+  optimise-store.cc
 
 pkginclude_HEADERS = \
- store-api.hh local-store.hh remote-store.hh derivations.hh misc.hh \
+  store-api.hh local-store.hh remote-store.hh derivations.hh misc.hh \
- globals.hh db.hh references.hh pathlocks.hh \
+  globals.hh db.hh references.hh pathlocks.hh \
- worker-protocol.hh
+  worker-protocol.hh
 
 libstore_la_LIBADD = ../libutil/libutil.la ../boost/format/libformat.la
 

src/libstore/build.cc

@@ -3,7 +3,6 @@
 #include "misc.hh"
 #include "globals.hh"
 #include "local-store.hh"
-#include "db.hh"
 #include "util.hh"
 
 #include <map>
@@ -207,7 +206,9 @@ private:
     
 public:
 
-    Worker();
+    LocalStore & store;
+
+    Worker(LocalStore & store);
     ~Worker();
 
     /* Make a goal (with caching). */
@@ -897,14 +898,14 @@ void DerivationGoal::haveDerivation()
         return;
     }
 
-    assert(store->isValidPath(drvPath));
+    assert(worker.store.isValidPath(drvPath));
 
     /* Get the derivation. */
     drv = derivationFromPath(drvPath);
 
     for (DerivationOutputs::iterator i = drv.outputs.begin();
          i != drv.outputs.end(); ++i)
-        store->addTempRoot(i->second.path);
+        worker.store.addTempRoot(i->second.path);
 
     /* Check what outputs paths are not already valid. */
     PathSet invalidOutputs = checkPathValidity(false);
@@ -938,7 +939,7 @@ void DerivationGoal::haveDerivation()
          i != invalidOutputs.end(); ++i)
         /* Don't bother creating a substitution goal if there are no
            substitutes. */
-        if (store->hasSubstitutes(*i))
+        if (worker.store.hasSubstitutes(*i))
             addWaitee(worker.makeSubstitutionGoal(*i));
     
     if (waitees.empty()) /* to prevent hang (no wake-up event) */
@@ -993,7 +994,7 @@ void DerivationGoal::outputsSubstituted()
             throw BuildError(format("`exportBuildReferencesGraph' contains a non-store path `%1%'")
                 % storePath);
         storePath = toStorePath(storePath);
-        if (!store->isValidPath(storePath))
+        if (!worker.store.isValidPath(storePath))
             throw BuildError(format("`exportBuildReferencesGraph' contains an invalid path `%1%'")
                 % storePath);
         
@@ -1250,19 +1251,6 @@ PathSet outputPaths(const DerivationOutputs & outputs)
 }
 
 
-string showPaths(const PathSet & paths)
-{
-    string s;
-    for (PathSet::const_iterator i = paths.begin();
-         i != paths.end(); ++i)
-    {
-        if (s.size() != 0) s += ", ";
-        s += "`" + *i + "'";
-    }
-    return s;
-}
-
-
 DerivationGoal::HookReply DerivationGoal::tryBuildHook()
 {
     if (!useBuildHook) return rpDecline;
@@ -1474,7 +1462,7 @@ DerivationGoal::PrepareBuildReply DerivationGoal::prepareBuild()
          i != drv.outputs.end(); ++i)
     {
         Path path = i->second.path;
-        if (store->isValidPath(path))
+        if (worker.store.isValidPath(path))
             throw BuildError(format("obstructed build: path `%1%' exists") % path);
         if (pathExists(path)) {
             debug(format("removing unregistered path `%1%'") % path);
@@ -1502,7 +1490,7 @@ DerivationGoal::PrepareBuildReply DerivationGoal::prepareBuild()
         /* Add the relevant output closures of the input derivation
            `*i' as input paths.  Only add the closures of output paths
            that are specified as inputs. */
-        assert(store->isValidPath(i->first));
+        assert(worker.store.isValidPath(i->first));
         Derivation inDrv = derivationFromPath(i->first);
         for (StringSet::iterator j = i->second.begin();
              j != i->second.end(); ++j)
@@ -1624,7 +1612,7 @@ void DerivationGoal::startBuilder()
             throw BuildError(format("`exportReferencesGraph' contains a non-store path `%1%'")
                 % storePath);
         storePath = toStorePath(storePath);
-        if (!store->isValidPath(storePath))
+        if (!worker.store.isValidPath(storePath))
             throw BuildError(format("`exportReferencesGraph' contains an invalid path `%1%'")
                 % storePath);
 
@@ -1652,7 +1640,7 @@ void DerivationGoal::startBuilder()
             throw BuildError(format("`exportBuildReferencesGraph' contains a non-store path `%1%'")
                 % storePath);
         storePath = toStorePath(storePath);
-        if (!store->isValidPath(storePath))
+        if (!worker.store.isValidPath(storePath))
             throw BuildError(format("`exportBuildReferencesGraph' contains an invalid path `%1%'")
                 % storePath);
 
@@ -1994,27 +1982,17 @@ void DerivationGoal::computeClosure()
     }
 
     /* Register each output path as valid, and register the sets of
-       paths referenced by each of them.  This is wrapped in one
+       paths referenced by each of them.  !!! this should be
-       database transaction to ensure that if we crash, either
+       atomic so that either all paths are registered as valid, or
-       everything is registered or nothing is.  This is for
+       none are. */
-       recoverability: unregistered paths in the store can be deleted
-       arbitrarily, while registered paths can only be deleted by
-       running the garbage collector.
-
-       The reason that we do the transaction here and not on the fly
-       while we are scanning (above) is so that we don't hold database
-       locks for too long. */
-    Transaction txn;
-    createStoreTransaction(txn);
     for (DerivationOutputs::iterator i = drv.outputs.begin(); 
          i != drv.outputs.end(); ++i)
     {
-        registerValidPath(txn, i->second.path,
+        worker.store.registerValidPath(i->second.path,
             contentHashes[i->second.path],
             allReferences[i->second.path],
             drvPath);
     }
-    txn.commit();
 
     /* It is now safe to delete the lock files, since all future
        lockers will see that the output paths are valid; they will not
@@ -2113,7 +2091,7 @@ PathSet DerivationGoal::checkPathValidity(bool returnValid)
     PathSet result;
     for (DerivationOutputs::iterator i = drv.outputs.begin();
          i != drv.outputs.end(); ++i)
-        if (store->isValidPath(i->second.path)) {
+        if (worker.store.isValidPath(i->second.path)) {
             if (returnValid) result.insert(i->second.path);
         } else {
             if (!returnValid) result.insert(i->second.path);
@@ -2219,10 +2197,10 @@ void SubstitutionGoal::init()
 {
     trace("init");
 
-    store->addTempRoot(storePath);
+    worker.store.addTempRoot(storePath);
     
     /* If the path already exists we're done. */
-    if (store->isValidPath(storePath)) {
+    if (worker.store.isValidPath(storePath)) {
         amDone(ecSuccess);
         return;
     }
@@ -2293,7 +2271,7 @@ void SubstitutionGoal::referencesValid()
     for (PathSet::iterator i = references.begin();
          i != references.end(); ++i)
         if (*i != storePath) /* ignore self-references */
-            assert(store->isValidPath(*i));
+            assert(worker.store.isValidPath(*i));
 
     state = &SubstitutionGoal::tryToRun;
     worker.waitForBuildSlot(shared_from_this());
@@ -2327,7 +2305,7 @@ void SubstitutionGoal::tryToRun()
         (format("waiting for lock on `%1%'") % storePath).str());
 
     /* Check again whether the path is invalid. */
-    if (store->isValidPath(storePath)) {
+    if (worker.store.isValidPath(storePath)) {
         debug(format("store path `%1%' has become valid") % storePath);
         outputLock->setDeletion(true);
         amDone(ecSuccess);
@@ -2434,11 +2412,8 @@ void SubstitutionGoal::finished()
 
     Hash contentHash = hashPath(htSHA256, storePath);
 
-    Transaction txn;
+    worker.store.registerValidPath(storePath, contentHash,
-    createStoreTransaction(txn);
-    registerValidPath(txn, storePath, contentHash,
         references, deriver);
-    txn.commit();
 
     outputLock->setDeletion(true);
     
@@ -2472,7 +2447,8 @@ void SubstitutionGoal::handleEOF(int fd)
 static bool working = false;
 
 
-Worker::Worker()
+Worker::Worker(LocalStore & store)
+    : store(store)
 {
     /* Debugging: prevent recursive workers. */ 
     if (working) abort();
@@ -2870,7 +2846,7 @@ void LocalStore::buildDerivations(const PathSet & drvPaths)
     startNest(nest, lvlDebug,
         format("building %1%") % showPaths(drvPaths));
 
-    Worker worker;
+    Worker worker(*this);
 
     Goals goals;
     for (PathSet::const_iterator i = drvPaths.begin();
@@ -2895,9 +2871,9 @@ void LocalStore::buildDerivations(const PathSet & drvPaths)
 void LocalStore::ensurePath(const Path & path)
 {
     /* If the path is already valid, we're done. */
-    if (store->isValidPath(path)) return;
+    if (isValidPath(path)) return;
 
-    Worker worker;
+    Worker worker(*this);
     GoalPtr goal = worker.makeSubstitutionGoal(path);
     Goals goals = singleton<Goals>(goal);
 

src/libstore/db.cc

@@ -1,3 +1,7 @@
+#include "config.h"
+
+#ifdef OLD_DB_COMPAT
+
 #include "db.hh"
 #include "util.hh"
 #include "pathlocks.hh"
@@ -466,3 +470,5 @@ void Database::clearTable(const Transaction & txn, TableId table)
 
 
 }
+
+#endif

src/libstore/gc.cc

@@ -2,8 +2,6 @@
 #include "misc.hh"
 #include "pathlocks.hh"
 #include "local-store.hh"
-#include "db.hh"
-#include "util.hh"
 
 #include <boost/shared_ptr.hpp>
 

src/libstore/local-store.hh

@@ -4,18 +4,16 @@
 #include <string>
 
 #include "store-api.hh"
+#include "util.hh"
 
 
 namespace nix {
 
 
-class Transaction;
-
-
 /* Nix store and database schema version.  Version 1 (or 0) was Nix <=
    0.7.  Version 2 was Nix 0.8 and 0.9.  Version 3 is Nix 0.10.
-   Version 4 is Nix 0.11. */
+   Version 4 is Nix 0.11.  Version 5 is Nix 0.12*/
-const int nixSchemaVersion = 4;
+const int nixSchemaVersion = 5;
 
 
 extern string drvsLogDir;
@@ -43,15 +41,9 @@ private:
     
 public:
 
-    /* Open the database environment.  If `reserveSpace' is true, make
+    /* Initialise the local store, upgrading the schema if
-       sure that a big empty file exists in /nix/var/nix/db/reserved.
+       necessary. */
-       If `reserveSpace' is false, delete this file if it exists.  The
+    LocalStore();
-       idea is that on normal operation, the file exists; but when we
-       run the garbage collector, it is deleted.  This is to ensure
-       that the garbage collector has a small amount of disk space
-       available, which is required to open the Berkeley DB
-       environment. */
-    LocalStore(bool reserveSpace);
 
     ~LocalStore();
     
@@ -100,33 +92,63 @@ public:
     void collectGarbage(GCAction action, const PathSet & pathsToDelete,
         bool ignoreLiveness, PathSet & result, unsigned long long & bytesFreed);
 
+    /* Delete a path from the Nix store. */
+    void deleteFromStore(const Path & path, unsigned long long & bytesFreed);
+    
     /* Optimise the disk space usage of the Nix store by hard-linking
        files with the same contents. */
     void optimiseStore(bool dryRun, OptimiseStats & stats);
+
+    /* Check the integrity of the Nix store. */
+    void verifyStore(bool checkContents);
+
+    /* Register the validity of a path, i.e., that `path' exists, that
+       the paths referenced by it exists, and in the case of an output
+       path of a derivation, that it has been produced by a succesful
+       execution of the derivation (or something equivalent).  Also
+       register the hash of the file system contents of the path.  The
+       hash must be a SHA-256 hash. */
+    void registerValidPath(const Path & path,
+        const Hash & hash, const PathSet & references, const Path & deriver);
+
+    void registerValidPaths(const ValidPathInfos & infos);
+
+private:
+
+    Path schemaPath;
+
+    /* Lock file used for upgrading. */
+    AutoCloseFD globalLock;
+
+    /* !!! The cache can grow very big.  Maybe it should be pruned
+       every once in a while. */
+    std::map<Path, ValidPathInfo> pathInfoCache;
+
+    /* Store paths for which the referrers file must be purged. */
+    PathSet delayedUpdates;
+
+    int getSchema();
+
+    void registerValidPath(const ValidPathInfo & info, bool ignoreValidity = false);
+
+    ValidPathInfo queryPathInfo(const Path & path);
+
+    void rewriteReferrers(const Path & path, bool purge, PathSet referrers);
+
+    void flushDelayedUpdates();
+    
+    bool queryReferrersInternal(const Path & path, PathSet & referrers);
+    
+    void invalidatePath(const Path & path);
+    
+    void upgradeStore12();
+
 };
 
 
-/* Get a transaction object. */
-void createStoreTransaction(Transaction & txn);
-
 /* Copy a path recursively. */
 void copyPath(const Path & src, const Path & dst);
 
-/* Register the validity of a path, i.e., that `path' exists, that the
-   paths referenced by it exists, and in the case of an output path of
-   a derivation, that it has been produced by a succesful execution of
-   the derivation (or something equivalent).  Also register the hash
-   of the file system contents of the path.  The hash must be a
-   SHA-256 hash. */
-void registerValidPath(const Transaction & txn,
-    const Path & path, const Hash & hash, const PathSet & references,
-    const Path & deriver);
-
-typedef list<ValidPathInfo> ValidPathInfos;
-
-void registerValidPaths(const Transaction & txn,
-    const ValidPathInfos & infos);
-
 /* "Fix", or canonicalise, the meta-data of the files in a store path
    after it has been built.  In particular:
    - the last modification date on each file is set to 0 (i.e.,
@@ -137,25 +159,10 @@ void registerValidPaths(const Transaction & txn,
      in a setuid Nix installation. */
 void canonicalisePathMetaData(const Path & path);
 
-/* Checks whether a path is valid. */ 
+void canonicalisePathMetaData(const Path & path, bool recurse);
-bool isValidPathTxn(const Transaction & txn, const Path & path);
-
-/* Sets the set of outgoing FS references for a store path.  Use with
-   care! */
-void setReferences(const Transaction & txn, const Path & path,
-    const PathSet & references);
-
-/* Sets the deriver of a store path.  Use with care! */
-void setDeriver(const Transaction & txn, const Path & path,
-    const Path & deriver);
-
-/* Delete a value from the nixStore directory. */
-void deleteFromStore(const Path & path, unsigned long long & bytesFreed);
 
 MakeError(PathInUse, Error);
 
-void verifyStore(bool checkContents);
-
 /* Whether we are in build users mode. */
 bool haveBuildUsers();
 

src/libstore/misc.cc

@@ -1,6 +1,5 @@
 #include "misc.hh"
 #include "store-api.hh"
-#include "db.hh"
 
 #include <aterm2.h>
 

src/libstore/optimise-store.cc

@@ -0,0 +1,129 @@
+#include "util.hh"
+#include "local-store.hh"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+
+namespace nix {
+
+
+typedef std::map<Hash, std::pair<Path, ino_t> > HashToPath;
+
+
+static void makeWritable(const Path & path)
+{
+    struct stat st;
+    if (lstat(path.c_str(), &st))
+	throw SysError(format("getting attributes of path `%1%'") % path);
+    if (chmod(path.c_str(), st.st_mode | S_IWUSR) == -1)
+        throw SysError(format("changing writability of `%1%'") % path);
+}
+
+
+static void hashAndLink(bool dryRun, HashToPath & hashToPath,
+    OptimiseStats & stats, const Path & path)
+{
+    struct stat st;
+    if (lstat(path.c_str(), &st))
+	throw SysError(format("getting attributes of path `%1%'") % path);
+
+    /* Sometimes SNAFUs can cause files in the Nix store to be
+       modified, in particular when running programs as root under
+       NixOS (example: $fontconfig/var/cache being modified).  Skip
+       those files. */
+    if (S_ISREG(st.st_mode) && (st.st_mode & S_IWUSR)) {
+        printMsg(lvlError, format("skipping suspicious writable file `%1%'") % path);
+        return;
+    }
+
+    /* We can hard link regular files and symlinks. */
+    if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
+
+        /* Hash the file.  Note that hashPath() returns the hash over
+           the NAR serialisation, which includes the execute bit on
+           the file.  Thus, executable and non-executable files with
+           the same contents *won't* be linked (which is good because
+           otherwise the permissions would be screwed up).
+
+           Also note that if `path' is a symlink, then we're hashing
+           the contents of the symlink (i.e. the result of
+           readlink()), not the contents of the target (which may not
+           even exist). */
+        Hash hash = hashPath(htSHA256, path);
+        stats.totalFiles++;
+        printMsg(lvlDebug, format("`%1%' has hash `%2%'") % path % printHash(hash));
+
+        std::pair<Path, ino_t> prevPath = hashToPath[hash];
+        
+        if (prevPath.first == "") {
+            hashToPath[hash] = std::pair<Path, ino_t>(path, st.st_ino);
+            return;
+        }
+            
+        /* Yes!  We've seen a file with the same contents.  Replace
+           the current file with a hard link to that file. */
+        stats.sameContents++;
+        if (prevPath.second == st.st_ino) {
+            printMsg(lvlDebug, format("`%1%' is already linked to `%2%'") % path % prevPath.first);
+            return;
+        }
+        
+        if (!dryRun) {
+            
+            printMsg(lvlTalkative, format("linking `%1%' to `%2%'") % path % prevPath.first);
+
+            Path tempLink = (format("%1%.tmp-%2%-%3%")
+                % path % getpid() % rand()).str();
+
+            /* Make the containing directory writable, but only if
+               it's not the store itself (we don't want or need to
+               mess with  its permissions). */
+            bool mustToggle = !isStorePath(path);
+            if (mustToggle) makeWritable(dirOf(path));
+        
+            if (link(prevPath.first.c_str(), tempLink.c_str()) == -1)
+                throw SysError(format("cannot link `%1%' to `%2%'")
+                    % tempLink % prevPath.first);
+
+            /* Atomically replace the old file with the new hard link. */
+            if (rename(tempLink.c_str(), path.c_str()) == -1)
+                throw SysError(format("cannot rename `%1%' to `%2%'")
+                    % tempLink % path);
+
+            /* Make the directory read-only again and reset its
+               timestamp back to 0. */
+            if (mustToggle) canonicalisePathMetaData(dirOf(path), false);
+            
+        } else
+            printMsg(lvlTalkative, format("would link `%1%' to `%2%'") % path % prevPath.first);
+        
+        stats.filesLinked++;
+        stats.bytesFreed += st.st_size;
+    }
+
+    if (S_ISDIR(st.st_mode)) {
+        Strings names = readDirectory(path);
+	for (Strings::iterator i = names.begin(); i != names.end(); ++i)
+	    hashAndLink(dryRun, hashToPath, stats, path + "/" + *i);
+    }
+}
+
+
+void LocalStore::optimiseStore(bool dryRun, OptimiseStats & stats)
+{
+    HashToPath hashToPath;
+
+    PathSet paths = queryValidPaths();
+
+    for (PathSet::iterator i = paths.begin(); i != paths.end(); ++i) {
+        addTempRoot(*i);
+        if (!isValidPath(*i)) continue; /* path was GC'ed, probably */
+        startNest(nest, lvlChatty, format("hashing files in `%1%'") % *i);
+        hashAndLink(dryRun, hashToPath, stats, *i);
+    }
+}
+
+
+}

src/libstore/store-api.cc

@@ -205,6 +205,19 @@ ValidPathInfo decodeValidPathInfo(std::istream & str, bool hashGiven)
 }
 
 
+string showPaths(const PathSet & paths)
+{
+    string s;
+    for (PathSet::const_iterator i = paths.begin();
+         i != paths.end(); ++i)
+    {
+        if (s.size() != 0) s += ", ";
+        s += "`" + *i + "'";
+    }
+    return s;
+}
+
+
 }
 
 
@@ -219,10 +232,10 @@ namespace nix {
 boost::shared_ptr<StoreAPI> store;
 
 
-boost::shared_ptr<StoreAPI> openStore(bool reserveSpace)
+boost::shared_ptr<StoreAPI> openStore()
 {
     if (getEnv("NIX_REMOTE") == "")
-        return boost::shared_ptr<StoreAPI>(new LocalStore(reserveSpace));
+        return boost::shared_ptr<StoreAPI>(new LocalStore());
     else
         return boost::shared_ptr<StoreAPI>(new RemoteStore());
 }

src/libstore/store-api.hh

@@ -249,7 +249,12 @@ extern boost::shared_ptr<StoreAPI> store;
 
 /* Factory method: open the Nix database, either through the local or
    remote implementation. */
-boost::shared_ptr<StoreAPI> openStore(bool reserveSpace = true);
+boost::shared_ptr<StoreAPI> openStore();
+
+
+/* Display a set of paths in human-readable form (i.e., between quotes
+   and separated by commas). */
+string showPaths(const PathSet & paths);
 
 
 string makeValidityRegistration(const PathSet & paths,
@@ -261,8 +266,12 @@ struct ValidPathInfo
     Path deriver;
     Hash hash;
     PathSet references;
+    time_t registrationTime;
+    ValidPathInfo() : registrationTime(0) { }
 };
 
+typedef list<ValidPathInfo> ValidPathInfos;
+
 ValidPathInfo decodeValidPathInfo(std::istream & str,
     bool hashGiven = false);
 

src/libstore/upgrade-schema.cc

@@ -0,0 +1,108 @@
+#include "db.hh"
+#include "hash.hh"
+#include "util.hh"
+#include "local-store.hh"
+#include "globals.hh"
+#include "pathlocks.hh"
+#include "config.h"
+
+#include <iostream>
+
+
+namespace nix {
+
+
+Hash parseHashField(const Path & path, const string & s);
+
+
+/* Upgrade from schema 4 (Nix 0.11) to schema 5 (Nix >= 0.12).  The
+   old schema uses Berkeley DB, the new one stores store path
+   meta-information in files. */
+void LocalStore::upgradeStore12()
+{
+#if OLD_DB_COMPAT
+    
+#ifdef __CYGWIN__
+    /* Cygwin can't upgrade a read lock to a write lock... */
+    lockFile(globalLock, ltNone, true);
+#endif
+
+    if (!lockFile(globalLock, ltWrite, false)) {
+        printMsg(lvlError, "waiting for exclusive access to the Nix store...");
+        lockFile(globalLock, ltWrite, true);
+    }
+
+    printMsg(lvlError, "upgrading Nix store to new schema (this may take a while)...");
+
+    if (getSchema() >= nixSchemaVersion) return; /* somebody else beat us to it */
+
+    /* Open the old Nix database and tables. */
+    Database nixDB;
+    nixDB.open(nixDBPath);
+    
+    /* dbValidPaths :: Path -> ()
+
+       The existence of a key $p$ indicates that path $p$ is valid
+       (that is, produced by a succesful build). */
+    TableId dbValidPaths = nixDB.openTable("validpaths");
+
+    /* dbReferences :: Path -> [Path]
+
+       This table lists the outgoing file system references for each
+       output path that has been built by a Nix derivation.  These are
+       found by scanning the path for the hash components of input
+       paths. */
+    TableId dbReferences = nixDB.openTable("references");
+
+    /* dbReferrers :: Path -> Path
+
+       This table is just the reverse mapping of dbReferences.  This
+       table can have duplicate keys, each corresponding value
+       denoting a single referrer. */
+    // Not needed for conversion: it's just the inverse of
+    // references.
+    // TableId dbReferrers = nixDB.openTable("referrers");
+
+    /* dbDerivers :: Path -> [Path]
+
+       This table lists the derivation used to build a path.  There
+       can only be multiple such paths for fixed-output derivations
+       (i.e., derivations specifying an expected hash). */
+    TableId dbDerivers = nixDB.openTable("derivers");
+
+    Paths paths;
+    nixDB.enumTable(noTxn, dbValidPaths, paths);
+    
+    for (Paths::iterator i = paths.begin(); i != paths.end(); ++i) {
+        ValidPathInfo info;
+        info.path = *i;
+        
+        Paths references;
+        nixDB.queryStrings(noTxn, dbReferences, *i, references);
+        info.references.insert(references.begin(), references.end());
+        
+        string s;
+        nixDB.queryString(noTxn, dbValidPaths, *i, s);
+        info.hash = parseHashField(*i, s);
+        
+        nixDB.queryString(noTxn, dbDerivers, *i, info.deriver);
+        
+        registerValidPath(info, true);
+        std::cerr << ".";
+    }
+
+    std::cerr << std::endl;
+
+    writeFile(schemaPath, (format("%1%") % nixSchemaVersion).str());
+
+    lockFile(globalLock, ltRead, true);
+
+#else
+    throw Error(
+        "Your Nix store has a database in Berkeley DB format. To convert\n"
+        "to the new format, please compile Nix with Berkeley DB support.");
+#endif
+}
+
+
+}

src/libutil/util.cc

@@ -361,9 +361,10 @@ Path createTempDir(const Path & tmpRoot, const Path & prefix,
 
 Paths createDirs(const Path & path)
 {
-    if (path == "/") return Paths();
+    Paths created;
-    Paths created = createDirs(dirOf(path));
+    if (path == "/") return created;
     if (!pathExists(path)) {
+        created = createDirs(dirOf(path));
         if (mkdir(path.c_str(), 0777) == -1)
             throw SysError(format("creating directory `%1%'") % path);
         created.push_back(path);

src/libutil/util.hh

@@ -12,6 +12,10 @@
 namespace nix {
 
 
+#define foreach(it_type, it, collection)                                \
+    for (it_type it = collection.begin(); it != collection.end(); ++it)
+
+
 /* Return an environment variable. */
 string getEnv(const string & key, const string & def = "");
 

src/nix-env/nix-env.cc

@@ -13,7 +13,6 @@
 #include "common-opts.hh"
 #include "xml-writer.hh"
 #include "store-api.hh"
-#include "db.hh"
 #include "util.hh"
 
 #include <cerrno>

src/nix-store/dotgraph.cc

@@ -1,7 +1,6 @@
 #include "dotgraph.hh"
 #include "util.hh"
 #include "store-api.hh"
-#include "db.hh"
 
 #include <iostream>
 

src/nix-store/nix-store.cc

@@ -7,7 +7,6 @@
 #include "shared.hh"
 #include "dotgraph.hh"
 #include "local-store.hh"
-#include "db.hh"
 #include "util.hh"
 #include "help.txt.hh"
 
@@ -31,6 +30,14 @@ static int rootNr = 0;
 static bool indirectRoot = false;
 
 
+LocalStore & ensureLocalStore()
+{
+    LocalStore * store2(dynamic_cast<LocalStore *>(store.get()));
+    if (!store2) throw Error("you don't have sufficient rights to use --verify");
+    return *store2;
+}
+
+
 static Path useDeriver(Path path)
 {       
     if (!isDerivation(path)) {
@@ -430,10 +437,7 @@ static void registerValidity(bool reregister, bool hashGiven, bool canonicalise)
         }
     }
 
-    Transaction txn;
+    ensureLocalStore().registerValidPaths(infos);
-    createStoreTransaction(txn);
-    registerValidPaths(txn, infos);
-    txn.commit();
 }
 
 
@@ -641,11 +645,10 @@ static void opVerify(Strings opFlags, Strings opArgs)
         if (*i == "--check-contents") checkContents = true;
         else throw UsageError(format("unknown flag `%1%'") % *i);
     
-    verifyStore(checkContents);
+    ensureLocalStore().verifyStore(checkContents);
 }
 
 
-
 static void showOptimiseStats(OptimiseStats & stats)
 {
     printMsg(lvlError,
@@ -671,12 +674,9 @@ static void opOptimise(Strings opFlags, Strings opArgs)
         if (*i == "--dry-run") dryRun = true;
         else throw UsageError(format("unknown flag `%1%'") % *i);
 
-    LocalStore * store2(dynamic_cast<LocalStore *>(store.get()));
-    if (!store2) throw Error("you don't have sufficient rights to use --optimise");
-
     OptimiseStats stats;
     try {
-        store2->optimiseStore(dryRun, stats);
+        ensureLocalStore().optimiseStore(dryRun, stats);
     } catch (...) {
         showOptimiseStats(stats);
         throw;
@@ -755,7 +755,7 @@ void run(Strings args)
     if (!op) throw UsageError("no operation specified");
 
     if (op != opDump && op != opRestore) /* !!! hack */
-        store = openStore(op != opGC);
+        store = openStore();
 
     op(opFlags, opArgs);
 }

src/nix-worker/nix-worker.cc

@@ -474,7 +474,7 @@ static void processConnection()
 #endif
 
         /* Open the store. */
-        store = boost::shared_ptr<StoreAPI>(new LocalStore(true));
+        store = boost::shared_ptr<StoreAPI>(new LocalStore());
 
         stopWork();
         

tests/Makefile.am

@@ -19,7 +19,7 @@ TESTS = init.sh hash.sh lang.sh add.sh simple.sh dependencies.sh \
   fallback.sh nix-push.sh gc.sh gc-concurrent.sh verify.sh nix-pull.sh \
   referrers.sh user-envs.sh logging.sh nix-build.sh misc.sh fixed.sh \
   gc-runtime.sh install-package.sh check-refs.sh filter-source.sh \
-  remote-store.sh
+  remote-store.sh export.sh
 
 XFAIL_TESTS =
 

tests/dependencies.sh

@@ -11,7 +11,7 @@ $nixstore -q --graph "$drvPath" > $TEST_ROOT/graph
 if test -n "$dot"; then
     # Does it parse?
     $dot < $TEST_ROOT/graph
-fi    
+fi
 
 outPath=$($nixstore -rvv "$drvPath")
 

tests/export.sh

@@ -0,0 +1,31 @@
+source common.sh
+
+clearStore
+
+outPath=$($nixstore -r $($nixinstantiate dependencies.nix))
+
+$nixstore --export $outPath > $TEST_ROOT/exp
+
+$nixstore --export $($nixstore -qR $outPath) > $TEST_ROOT/exp_all
+
+
+clearStore
+
+if $nixstore --import < $TEST_ROOT/exp; then
+    echo "importing a non-closure should fail"
+    exit 1
+fi
+
+
+clearStore
+
+$nixstore --import < $TEST_ROOT/exp_all
+
+$nixstore --export $($nixstore -qR $outPath) > $TEST_ROOT/exp_all2
+
+
+clearStore
+
+# Regression test: the derivers in exp_all2 are empty, which shouldn't
+# cause a failure.
+$nixstore --import < $TEST_ROOT/exp_all2

tests/init.sh

@@ -95,4 +95,5 @@ chmod +x $NIX_BIN_DIR/nix/download-using-manifests.pl
 $nixstore --init
 
 # Did anything happen?
-test -e "$NIX_DB_DIR"/validpaths
+test -e "$NIX_DB_DIR"/info
+test -e "$NIX_DB_DIR"/referrer

tests/referrers.sh

@@ -9,12 +9,50 @@ reference=$NIX_STORE_DIR/abcdef
 touch $reference
 (echo $reference && echo && echo 0) | $nixstore --register-validity 
 
-echo "registering..."
+echo "making registration..."
-time for ((n = 0; n < $max; n++)); do
+
+for ((n = 0; n < $max; n++)); do
     storePath=$NIX_STORE_DIR/$n
     touch $storePath
-    (echo $storePath && echo && echo 1 && echo $reference)
+    ref2=$NIX_STORE_DIR/$((n+1))
-done | $nixstore --register-validity 
+    if test $((n+1)) = $max; then
+        ref2=$reference
+    fi
+    (echo $storePath && echo && echo 2 && echo $reference && echo $ref2)
+done > $TEST_ROOT/reg_info
+
+echo "registering..."
+
+time $nixstore --register-validity < $TEST_ROOT/reg_info
+
+oldTime=$(cat test-tmp/db/info/1 | grep Registered-At)
+
+echo "sleeping..."
+
+sleep 2
+
+echo "reregistering..."
+
+time $nixstore --register-validity --reregister < $TEST_ROOT/reg_info
+
+newTime=$(cat test-tmp/db/info/1 | grep Registered-At)
+
+if test "$newTime" != "$oldTime"; then
+    echo "reregistration changed original registration time"
+    exit 1
+fi
+
+if test "$(cat test-tmp/db/referrer/1 | wc -w)" != 1; then
+    echo "reregistration duplicated referrers"
+    exit 1
+fi
 
 echo "collecting garbage..."
-time $nixstore --gc 2> /dev/null
+ln -sfn $reference "$NIX_STATE_DIR"/gcroots/ref
+time $nixstore --gc
+
+if test "$(cat test-tmp/db/referrer/abcdef | wc -w)" != 0; then
+    echo "referrers not cleaned up"
+    exit 1
+fi
+