Deal with order dependence in dist rule

1 files changed, 40 insertions, 0 deletions

diff --git a/libbuild2/dist/types.hxx b/libbuild2/dist/types.hxx
new file mode 100644
index 0000000..f3b1009
--- /dev/null
+++ b/libbuild2/dist/types.hxx
@@ -0,0 +1,40 @@
+// file      : libbuild2/dist/types.hxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_DIST_TYPES_HXX
+#define LIBBUILD2_DIST_TYPES_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/forward.hxx>
+
+#include <libbuild2/prerequisite-key.hxx>
+
+namespace build2
+{
+  namespace dist
+  {
+    // List of prerequisites that could not be searched to a target and were
+    // postponed for later re-search. This can happen, for example, because a
+    // prerequisite would resolve to a member of a group that hasn't been
+    // matched yet (for example, libs{} of lib{}). See rule::apply() for
+    // details.
+    //
+    // Note that we are using list instead of vector because new elements can
+    // be added at the end while we are iterating over the list.
+    //
+    struct postponed_prerequisite
+    {
+      build2::action                          action;
+      reference_wrapper<const build2::target> target;
+      reference_wrapper<const prerequisite>   prereq;
+    };
+
+    struct postponed_prerequisites
+    {
+      build2::mutex                        mutex;
+      build2::list<postponed_prerequisite> list;
+    };
+  }
+}
+
+#endif // LIBBUILD2_DIST_TYPES_HXX