* Adapted nix-pull to use the new substitute mechanism.

configure.ac

@@ -152,6 +152,7 @@ AC_CONFIG_FILES([Makefile
    corepkgs/nar/Makefile
    corepkgs/buildenv/Makefile
    corepkgs/channels/Makefile
+   corepkgs/nix-pull/Makefile
    doc/Makefile
    doc/manual/Makefile
    misc/Makefile

corepkgs/Makefile.am

@@ -1 +1 @@
-SUBDIRS = fetchurl nar buildenv channels
+SUBDIRS = fetchurl nar buildenv channels nix-pull

corepkgs/nix-pull/Makefile.am

@@ -0,0 +1,11 @@
+all-local: builder.sh
+
+install-exec-local:
+	$(INSTALL) -d $(DESTDIR)$(datadir)/nix/corepkgs
+	$(INSTALL) -d $(DESTDIR)$(datadir)/nix/corepkgs/nix-pull
+	$(INSTALL_DATA) default.nix $(DESTDIR)$(datadir)/nix/corepkgs/nix-pull
+	$(INSTALL_PROGRAM) builder.sh $(DESTDIR)$(datadir)/nix/corepkgs/nix-pull
+
+include ../../substitute.mk
+
+EXTRA_DIST = default.nix builder.sh.in

corepkgs/nix-pull/builder.sh.in

@@ -0,0 +1,34 @@
+#! @shell@ -e
+
+export PATH=/bin:/usr/bin
+
+mkdir $out
+
+cat > $out/fetch <<EOF
+#! @shell@ -e
+
+export PATH=/bin:/usr/bin
+
+echo "downloading \$2..."
+
+export PRINT_PATH=1
+result=(\$(@bindir@/nix-prefetch-url \$2))
+
+hash=\${result[0]}
+path=\${result[1]}
+
+if test "\$hash" != "\$3"; then
+    echo "hash is \$hash, expected \$3"
+    exit 1
+fi
+
+echo "unpacking into \$1..."
+
+if ! @bunzip2@ < "\$path" | @bindir@/nix-store --restore "\$1"; then
+    exit 1
+fi
+
+exit 0
+EOF
+
+chmod +x $out/fetch

corepkgs/nix-pull/default.nix

@@ -0,0 +1,7 @@
+{system}:
+
+derivation {
+  name = "nix-pull";
+  builder = ./builder.sh;
+  inherit system;
+}

scripts/nix-prefetch-url.in

@@ -25,13 +25,17 @@ test -e $tmpPath2 || mv $tmpPath1 $tmpPath2 # !!! race
 storeExpr=$( \
   echo "(import @datadir@/nix/corepkgs/fetchurl) \
         {url = $url; md5 = \"$hash\"; system = \"@system@\";}" \
-  | nix-instantiate -)
+  | @bindir@/nix-instantiate -)
 
 # Realise it.
-finalPath=$(nix-store -qnB --force-realise $storeExpr)
+finalPath=$(@bindir@/nix-store -qnB --force-realise $storeExpr)
 
 echo "path is $finalPath" >&2
 
 rm -rf $tmpPath2 || true
 
 echo $hash
+
+if test -n "$PRINT_PATH"; then
+    echo $finalPath
+fi

scripts/nix-pull.in

@@ -10,18 +10,18 @@ do { $tmpdir = tmpnam(); }
 until mkdir $tmpdir, 0777;
 
 my $manifest = "$tmpdir/manifest";
-my $conffile = "@sysconfdir@/nix/prebuilts.conf";
+my $confFile = "@sysconfdir@/nix/prebuilts.conf";
 
 #END { unlink $manifest; rmdir $tmpdir; }
 
 
 # Obtain URLs either from the command line or from a configuration file.
-my %storepaths2urls;
+my %storePaths2urls;
 my %urls2hashes;
 my %successors;
 sub doURL {
     my $url = shift;
-    processURL $manifest, $url, \%storepaths2urls, \%urls2hashes, \%successors;
+    processURL $manifest, $url, \%storePaths2urls, \%urls2hashes, \%successors;
 }
 if (scalar @ARGV > 0) {
     while (@ARGV) {
@@ -29,7 +29,7 @@ if (scalar @ARGV > 0) {
 	doURL $url;
     }
 } else {
-    open CONFFILE, "<$conffile";
+    open CONFFILE, "<$confFile";
     while (<CONFFILE>) {
         chomp;
         if (/^\s*(\S+)\s*(\#.*)?$/) {
@@ -41,60 +41,44 @@ if (scalar @ARGV > 0) {
 }
 
 
-# Create a Nix expression for the substitutes.
+my $size = scalar (keys %storePaths2urls);
-my $fullexpr = "[";
+print "$size store paths in manifest\n";
-
-my @storepaths;
-foreach my $storepath (keys %storepaths2urls) {
-    # Construct a Nix expression that fetches and unpacks a
-    # Nix archive from the network.
-    my $url = $storepaths2urls{$storepath};
-    my $hash = $urls2hashes{$url};
-    my $fetch =
-	"(import @datadir@/nix/corepkgs/fetchurl) " .
-	"{url = $url; md5 = \"$hash\"; system = \"@system@\";}";
-    my $nixexpr =
-	"((import @datadir@/nix/corepkgs/nar/unnar.nix) " .
-	"{narFile = ($fetch); outPath = \"$storepath\"; system = \"@system@\";}) ";
-    $fullexpr .= $nixexpr; # !!! O(n^2)?
-    push @storepaths, $storepath;
-}
-
-$fullexpr .= "]";
 
 
-# Instantiate store expressions from the Nix expressions we created above.
+# Instantiate a store expression that builds the substitute program
-print STDERR "instantiating store expressions...\n";
+# (the program that fetches URLs and unpacks them into the store).
-my $pid = open2(\*READ, \*WRITE, "@bindir@/nix-instantiate -") or die "cannot run nix-instantiate";
+my $nixExpr =
+    "(import @datadir@/nix/corepkgs/nix-pull) " .
+    "{system = \"@system@\";}";
 
-print WRITE $fullexpr;
+print STDERR "instantiating store expression...\n";
-close WRITE;
+my $storeExpr = `echo '$nixExpr' | @bindir@/nix-instantiate -`
-my $i = 0;
+    or die "cannot instantiate Nix expression";
-my %substitutes;
+chomp $storeExpr;
-while (<READ>) {
-    chomp;
-    die unless /^\//;
-    my $subpath = $_;
-    die unless ($i < scalar @storepaths);
-    $substitutes{$storepaths[$i++]} = $subpath;
-}
-
-waitpid $pid, 0;
-$? == 0 or die "nix-instantiate failed";
 
 
 # Register all substitutes.
 print STDERR "registering substitutes...\n";
-my @subs = %substitutes;
+
-while (scalar @subs > 0) {
+my $pid = open2(\*READ, \*WRITE, "@bindir@/nix-store --substitute")
-    my $n = scalar @subs;
+    or die "cannot run nix-store";
-    if ($n > 256) { $n = 256 };
+
-    my @subs2 = @subs[0..$n - 1];
+close READ;
-    @subs = @subs[$n..scalar @subs - 1];
+
-    system "@bindir@/nix-store --substitute @subs2";
+foreach my $storePath (keys %storePaths2urls) {
-    if ($?) { die "`nix-store --substitute' failed"; }
+    print WRITE "$storePath\n";
+    print WRITE "$storeExpr\n";
+    print WRITE "/fetch\n";
+    print WRITE "2\n";
+    print WRITE "$storePaths2urls{$storePath}\n";
+    print WRITE "$urls2hashes{$storePaths2urls{$storePath}}\n";
 }
 
+close WRITE;
+
+waitpid $pid, 0;
+$? == 0 or die "nix-store failed";
+
 
 # Register all successors.
 print STDERR "registering successors...\n";

scripts/readmanifest.pm.in

@@ -3,7 +3,7 @@ use strict;
 sub processURL {
     my $manifest = shift;
     my $url = shift;
-    my $storepaths2urls = shift;
+    my $storePaths2urls = shift;
     my $urls2hashes = shift;
     my $successors = shift;
 
@@ -18,7 +18,7 @@ sub processURL {
 
     my $inside = 0;
 
-    my $storepath;
+    my $storePath;
     my $narurl;
     my $hash;
     my @preds;
@@ -31,7 +31,7 @@ sub processURL {
         if (!$inside) {
             if (/^\{$/) { 
                 $inside = 1;
-                undef $storepath;
+                undef $storePath;
                 undef $narurl;
                 undef $hash;
                 @preds = ();
@@ -41,16 +41,16 @@ sub processURL {
             if (/^\}$/) {
                 $inside = 0;
 
-		$$storepaths2urls{$storepath} = $narurl;
+		$$storePaths2urls{$storePath} = $narurl;
 		$$urls2hashes{$narurl} = $hash;
 
                 foreach my $p (@preds) {
-		    $$successors{$p} = $storepath;
+		    $$successors{$p} = $storePath;
                 }
 
             }
             elsif (/^\s*StorePath:\s*(\/\S+)\s*$/) {
-                $storepath = $1;
+                $storePath = $1;
             }
             elsif (/^\s*NarURL:\s*(\S+)\s*$/) {
                 $narurl = $1;