Implement nested id support

Now the 'id' specifier can optionally include the data member path
to the id inside the composite value. For example:

#pragma db id(first)
std::pair<int, int> p;

Note that one somewhat counter-intuitive aspect of this new feature
is that the whole member marked with id ('p' in the above example)
and not just the actual id member ('p.first' in the above example)
is treated as readonly.

Such nested id also cannot be automatically assigned (auto specifier).

1 files changed, 53 insertions, 23 deletions

diff --git a/odb/relational/source.cxx b/odb/relational/source.cxx
index 83e3c40..3b96ab5 100644
--- a/odb/relational/source.cxx
+++ b/odb/relational/source.cxx
@@ -19,9 +19,11 @@ traverse_object (type& c)
 {
   using semantics::data_member;
 
-  data_member* id (id_member (c));
+  data_member_path* id (id_member (c));
+  data_member* idf (id ? id->front () : 0);
+  data_member* idb (id ? id->back () : 0);
   bool auto_id (id && auto_ (*id));
-  bool base_id (id && &id->scope () != &c); // Comes from base.
+  bool base_id (id && &idf->scope () != &c); // Comes from base.
 
   data_member* opt (optimistic (c));
 
@@ -42,7 +44,7 @@ traverse_object (type& c)
   if (generate_grow)
   {
     grow = context::grow (c);
-    grow_id = (id ? context::grow (*id) : false) ||
+    grow_id = (id ? context::grow (*idb) : false) ||
       (opt ? context::grow (*opt) : false);
   }
 
@@ -188,7 +190,7 @@ traverse_object (type& c)
          << "ODB_POTENTIALLY_UNUSED (db);"
          << endl
          << "id_type id;";
-      init_id_value_member_id_image_->traverse (*id);
+      init_id_value_member_id_image_->traverse (*idb);
       os << "return id;"
          << "}";
     }
@@ -205,7 +207,35 @@ traverse_object (type& c)
          << "ODB_POTENTIALLY_UNUSED (db);"
          << endl
          << "id_type id;";
-      init_id_value_member_->traverse (*id);
+
+      // Handle nested id.
+      //
+      if (id->size () > 1)
+      {
+        string var;
+
+        for (data_member_path::const_iterator i (id->begin ());
+             i != id->end ();
+             ++i)
+        {
+          // The same logic as in member_base.
+          //
+          if (!var.empty ())
+            var += "value."; // Composite.
+
+          string const& name ((*i)->name ());
+          var += name;
+
+          if (name[name.size () - 1] != '_')
+            var += '_';
+        }
+
+        instance<init_value_member> t ("id", var);
+        t->traverse (*idb);
+      }
+      else
+        init_id_value_member_->traverse (*idb);
+
       os << "return id;"
          << "}";
     }
@@ -339,7 +369,7 @@ traverse_object (type& c)
   {
     // The id reference comes first in the insert statement.
     //
-    os << "// " << id->name () << endl
+    os << "// " << idf->name () << endl
        << "//" << endl
        << "if (sk == statement_insert)"
        << "{"
@@ -358,7 +388,7 @@ traverse_object (type& c)
     // The id reference comes last in the update statement.
     //
     if (!readonly)
-      os << "// " << id->name () << endl
+      os << "// " << idf->name () << endl
          << "//" << endl
          << "if (sk == statement_update)"
          << "{"
@@ -398,7 +428,7 @@ traverse_object (type& c)
     if (composite_wrapper (utype (*id)))
       os << db << "::statement_kind sk (" << db << "::statement_select);";
 
-    bind_id_member_->traverse (*id);
+    bind_id_member_->traverse (*idb);
 
     if (opt != 0)
     {
@@ -516,7 +546,7 @@ traverse_object (type& c)
     if (composite_wrapper (utype (*id)))
       os << db << "::statement_kind sk (" << db << "::statement_select);";
 
-    init_id_image_member_->traverse (*id);
+    init_id_image_member_->traverse (*idb);
 
     if (opt != 0)
     {
@@ -1222,9 +1252,9 @@ traverse_object (type& c)
 
   if (!poly_derived && auto_id && insert_send_auto_id)
   {
-    string const& n (id->name ());
+    string const& n (idf->name ());
     string var ("im." + n + (n[n.size () - 1] == '_' ? "" : "_"));
-    init_auto_id (*id, var);
+    init_auto_id (*idf, var); // idf == idb, since auto
     os << endl;
   }
 
@@ -1278,9 +1308,9 @@ traverse_object (type& c)
      << "throw object_already_persistent ();"
      << endl;
 
-  if (!poly_derived && auto_id)
+  if (!poly_derived && auto_id) // idf == idb since auto
   {
-    set_member (*id, "obj", "id (sts.id_image ())", "db", "id_type");
+    set_member (*idf, "obj", "id (sts.id_image ())", "db", "id_type");
     os << endl;
   }
 
@@ -1486,9 +1516,9 @@ traverse_object (type& c)
 
     // Extract auto id.
     //
-    if (auto_id)
+    if (auto_id) // idb == idf, since auto
     {
-      set_member (*id, "obj", "id (sts.id_image (i))", "db", "id_type");
+      set_member (*idf, "obj", "id (sts.id_image (i))", "db", "id_type");
       os << endl;
     }
 
@@ -4867,7 +4897,7 @@ traverse_view (type& c)
           {
             // container.value = pointer.id
             //
-            semantics::data_member& id (*id_member (*e.vo->obj));
+            data_member_path& id (*id_member (*e.vo->obj));
 
             c_cols->traverse (imb, utype (id), "value", "value");
             o_cols->traverse (id);
@@ -4877,7 +4907,7 @@ traverse_view (type& c)
           {
             // container.id = pointed-to.id
             //
-            semantics::data_member& id (*id_member (*vo->obj));
+            data_member_path& id (*id_member (*vo->obj));
 
             c_cols->traverse (imb, utype (id), "id", "object_id", vo->obj);
             o_cols->traverse (id);
@@ -4890,7 +4920,7 @@ traverse_view (type& c)
           {
             // container.id = pointer.id
             //
-            semantics::data_member& id (*id_member (*e.vo->obj));
+            data_member_path& id (*id_member (*e.vo->obj));
 
             c_cols->traverse (
               m, utype (id), "id", "object_id", e.vo->obj);
@@ -4901,7 +4931,7 @@ traverse_view (type& c)
           {
             // container.value = pointed-to.id
             //
-            semantics::data_member& id (*id_member (*vo->obj));
+            data_member_path& id (*id_member (*vo->obj));
 
             c_cols->traverse (m, utype (id), "value", "value");
             o_cols->traverse (id);
@@ -4961,7 +4991,7 @@ traverse_view (type& c)
           {
             // container.id = pointed-to.id
             //
-            semantics::data_member& id (*id_member (*vo->obj));
+            data_member_path& id (*id_member (*vo->obj));
 
             c_cols->traverse (imb, utype (id), "id", "object_id", vo->obj);
             o_cols->traverse (id);
@@ -4971,7 +5001,7 @@ traverse_view (type& c)
           {
             // container.value = pointer.id
             //
-            semantics::data_member& id (*id_member (*e.vo->obj));
+            data_member_path& id (*id_member (*e.vo->obj));
 
             c_cols->traverse (imb, utype (id), "value", "value");
             o_cols->traverse (id);
@@ -4984,7 +5014,7 @@ traverse_view (type& c)
           {
             // container.value = pointed-to.id
             //
-            semantics::data_member& id (*id_member (*vo->obj));
+            data_member_path& id (*id_member (*vo->obj));
 
             c_cols->traverse (m, utype (id), "value", "value");
             o_cols->traverse (id);
@@ -4994,7 +5024,7 @@ traverse_view (type& c)
           {
             // container.id = pointer.id
             //
-            semantics::data_member& id (*id_member (*e.vo->obj));
+            data_member_path& id (*id_member (*e.vo->obj));
 
             c_cols->traverse (m, utype (id), "id", "object_id", e.vo->obj);
             o_cols->traverse (id);