Add a function queryValidPaths()

queryValidPaths() combines multiple calls to isValidPath() in one.
This matters when using the Nix daemon because it reduces latency.
For instance, on "nix-env -qas \*" it reduces execution time from 5.7s
to 4.7s (which is indistinguishable from the non-daemon case).

1 files changed, 17 insertions, 0 deletions

diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 04a9e28c9007..0cd29c5751d2 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -217,6 +217,23 @@ bool RemoteStore::isValidPath(const Path & path)
 }
 
 
+PathSet RemoteStore::queryValidPaths(const PathSet & paths)
+{
+    if (GET_PROTOCOL_MINOR(daemonVersion) < 12) {
+        PathSet res;
+        foreach (PathSet::const_iterator, i, paths)
+            if (isValidPath(*i)) res.insert(*i);
+        return res;
+    } else {
+        openConnection();
+        writeInt(wopQueryValidPaths, to);
+        writeStrings(paths, to);
+        processStderr();
+        return readStorePaths<PathSet>(from);
+    }
+}
+
+
 PathSet RemoteStore::queryAllValidPaths()
 {
     openConnection();