Add --graphml option to the nix-store --query command

This prints the references graph of the store paths in the graphML
format [1]. The graphML format is supported by several graph tools
such as the Python Networkx library or the Apache Thinkerpop project.

[1] http://graphml.graphdrawing.org

1 files changed, 13 insertions, 1 deletions

diff --git a/src/nix-store/nix-store.cc b/src/nix-store/nix-store.cc
index fe68f681ae..4051fdbe16 100644
--- a/src/nix-store/nix-store.cc
+++ b/src/nix-store/nix-store.cc
@@ -9,6 +9,7 @@
 #include "util.hh"
 #include "worker-protocol.hh"
 #include "xmlgraph.hh"
+#include "graphml.hh"
 
 #include <iostream>
 #include <algorithm>
@@ -273,7 +274,7 @@ static void opQuery(Strings opFlags, Strings opArgs)
     enum QueryType
         { qDefault, qOutputs, qRequisites, qReferences, qReferrers
         , qReferrersClosure, qDeriver, qBinding, qHash, qSize
-        , qTree, qGraph, qXml, qResolve, qRoots };
+        , qTree, qGraph, qXml, qGraphML, qResolve, qRoots };
     QueryType query = qDefault;
     bool useOutput = false;
     bool includeOutputs = false;
@@ -300,6 +301,7 @@ static void opQuery(Strings opFlags, Strings opArgs)
         else if (i == "--tree") query = qTree;
         else if (i == "--graph") query = qGraph;
         else if (i == "--xml") query = qXml;
+        else if (i == "--graphml") query = qGraphML;
         else if (i == "--resolve") query = qResolve;
         else if (i == "--roots") query = qRoots;
         else if (i == "--use-output" || i == "-u") useOutput = true;
@@ -413,6 +415,16 @@ static void opQuery(Strings opFlags, Strings opArgs)
             break;
         }
 
+        case qGraphML: {
+            PathSet roots;
+            for (auto & i : opArgs) {
+                PathSet paths = maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise);
+                roots.insert(paths.begin(), paths.end());
+            }
+            printGraphML(ref<Store>(store), roots);
+            break;
+        }
+
         case qResolve: {
             for (auto & i : opArgs)
                 cout << format("%1%\n") % store->followLinksToStorePath(i);