Implement rep-fetch command

1 files changed, 42 insertions, 0 deletions

diff --git a/bpkg/database b/bpkg/database
index 05ffb04..f7de4d5 100644
--- a/bpkg/database
+++ b/bpkg/database
@@ -5,6 +5,9 @@
 #ifndef BPKG_DATABASE
 #define BPKG_DATABASE
 
+#include <utility> // forward()
+
+#include <odb/session.hxx>
 #include <odb/sqlite/database.hxx>
 
 #include <bpkg/types>
@@ -12,6 +15,8 @@
 
 namespace bpkg
 {
+  using odb::session;
+
   using odb::sqlite::database;
   using odb::sqlite::transaction;
 
@@ -28,6 +33,43 @@ namespace bpkg
     database& db_;
     odb::tracer* t_;
   };
+
+  // Range-based for-loop iteration over query result that returns
+  // object pointers. For example:
+  //
+  // for (shared_ptr<object> o: pointer_result (db.query<object> (...)))
+  //
+  template <typename R>
+  class pointer_result_range
+  {
+    R r_;
+
+  public:
+    pointer_result_range (R&& r): r_ (std::forward<R> (r)) {}
+
+    using base_iterator = typename R::iterator;
+
+    struct iterator: base_iterator
+    {
+      iterator () = default;
+
+      explicit
+      iterator (base_iterator i): base_iterator (std::move (i)) {}
+
+      typename base_iterator::pointer_type
+      operator* () {return this->load ();}
+    };
+
+    iterator begin () {return iterator (r_.begin ());}
+    iterator end () {return iterator (r_.end ());}
+  };
+
+  template <typename R>
+  inline pointer_result_range<R>
+  pointer_result (R&& r)
+  {
+    return pointer_result_range<R> (std::forward<R> (r));
+  }
 }
 
 #endif // BPKG_DATABASE