From b8554760aa3a5c5697c77d11e507a2bb46dbf8e4 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 10 Jul 2012 15:17:16 +0200
Subject: Add support for custom database type mapping

New pragma qualifier, map, and specifiers: as, to, from. New tests:
<database>/custom.
---
 odb/relational/context.hxx | 65 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

(limited to 'odb/relational/context.hxx')

diff --git a/odb/relational/context.hxx b/odb/relational/context.hxx
index 60ed934..ca55650 100644
--- a/odb/relational/context.hxx
+++ b/odb/relational/context.hxx
@@ -23,6 +23,19 @@ namespace relational
     statement_where   // WHERE clause.
   };
 
+  // Custom database type mapping.
+  //
+  struct custom_db_type
+  {
+    regex type;
+    std::string as;
+    std::string to;
+    std::string from;
+    location_t loc;
+  };
+
+  typedef std::vector<custom_db_type> custom_db_types;
+
   class context: public virtual ::context
   {
   public:
@@ -94,6 +107,58 @@ namespace relational
       return quote_id (table_name (m, p));
     }
 
+    // Custom database type conversion.
+    //
+  public:
+    string
+    convert_to (string const& expr,
+                string const& sqlt,
+                semantics::data_member& m)
+    {
+      string const& conv (current ().convert_expr (sqlt, m, true));
+      return conv.empty () ? expr : convert (expr, conv);
+    }
+
+    string
+    convert_from (string const& expr,
+                  string const& sqlt,
+                  semantics::data_member& m)
+    {
+      string const& conv (current ().convert_expr (sqlt, m, false));
+      return conv.empty () ? expr : convert (expr, conv);
+    }
+
+    // These shortcut versions should only be used on special members
+    // (e.g., auto id, version, etc) since they may not determine the
+    // proper SQL type in other cases (prefixes, composite ids, etc).
+    //
+    string
+    convert_to (string const& expr, semantics::data_member& m)
+    {
+      return convert_to (expr, column_type (m), m);
+    }
+
+    string
+    convert_from (string const& expr, semantics::data_member& m)
+    {
+      return convert_from (expr, column_type (m), m);
+    }
+
+    // Return the conversion expression itself.
+    //
+    string const&
+    convert_to_expr (string const& sqlt, semantics::data_member& m)
+    {
+      return current ().convert_expr (sqlt, m, true);
+    }
+
+  protected:
+    virtual string const&
+    convert_expr (string const& sqlt, semantics::data_member&, bool to);
+
+    string
+    convert (string const& expr, string const& conv);
+
   protected:
     // The default implementation returns false.
     //
-- 
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