From 6e3ac760696d4ec43138b1aba82426582c767072 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 19 Aug 2011 14:08:16 +0200
Subject: Rework query machinery not to use '_' as primary table alias

Now we always qualify with the actual table name and use the '_'
alias for situations where an object is referencing itself.
---
 odb/pgsql/query.cxx | 155 ++++++++++++++++++++++++++++------------------------
 odb/pgsql/query.hxx |  99 ++++++++++++++++++++-------------
 odb/pgsql/query.txx |  16 +++---
 3 files changed, 152 insertions(+), 118 deletions(-)

diff --git a/odb/pgsql/query.cxx b/odb/pgsql/query.cxx
index 1c5f9d4..856c031 100644
--- a/odb/pgsql/query.cxx
+++ b/odb/pgsql/query.cxx
@@ -28,7 +28,6 @@ namespace odb
     query (const query& q)
         : clause_ (q.clause_),
           parameters_ (q.parameters_),
-          parameter_offsets_ (q.parameter_offsets_),
           bind_ (q.bind_),
           binding_ (0, 0),
           values_ (q.values_),
@@ -70,7 +69,6 @@ namespace odb
       {
         clause_ = q.clause_;
         parameters_ = q.parameters_;
-        parameter_offsets_ = q.parameter_offsets_;
         bind_ = q.bind_;
 
         size_t n (bind_.size ());
@@ -108,56 +106,7 @@ namespace odb
     query& query::
     operator+= (const query& q)
     {
-      size_t cur_pos (0);
-
-      // Append the argument clause to the clause of this instance.
-      //
-      for (size_t i (0),
-             p (parameters_.size () + 1),
-             e (q.parameter_offsets_.size ());
-           i < e;
-           ++i, ++p)
-      {
-        size_t n (clause_.size ());
-
-        if (n != 0 && clause_[n - 1] != ' ' && q.clause_[cur_pos] != ' ')
-          clause_ += ' ';
-
-        parameter_offset o (q.parameter_offsets_[i]);
-
-        // Append all characters up to the start of the current
-        // parameter specifier, including the '$'.
-        //
-        clause_.append (q.clause_, cur_pos, o.first - cur_pos + 1);
-
-        // Advance current position in source clause to 1 element past
-        // the current parameter specifier.
-        //
-        cur_pos = o.second;
-
-        // Insert the correct parameter number and update the parameter
-        // offset to describe its offset in the new clause.
-        //
-        o.first = clause_.size () - 1;
-        ostringstream os;
-        os << p;
-        clause_.append (os.str ());
-        o.second = clause_.size ();
-
-        parameter_offsets_.push_back (o);
-      }
-
-      // Copy any remaining characters in q.clause_.
-      //
-      if (cur_pos < q.clause_.size ())
-      {
-        size_t n (clause_.size ());
-
-        if (n != 0 && clause_[n - 1] != ' ' && q.clause_[cur_pos] != ' ')
-          clause_ += ' ';
-
-        clause_.append (q.clause_, cur_pos, string::npos);
-      }
+      clause_.insert (clause_.end (), q.clause_.begin (), q.clause_.end ());
 
       size_t n (bind_.size ());
 
@@ -204,22 +153,34 @@ namespace odb
     }
 
     void query::
-    add (details::shared_ptr<query_param> p)
+    append (const string& q, clause_part::kind_type k)
     {
-      size_t n (clause_.size ());
+      if (k == clause_part::native &&
+          !clause_.empty () &&
+          clause_.back ().kind == clause_part::native)
+      {
+        string& s (clause_.back ().part);
 
-      if (n != 0 && clause_[n - 1] != ' ')
-        clause_ += ' ';
+        char first (!q.empty () ? q[0] : ' ');
+        char last (!s.empty () ? s[s.size () - 1] : ' ');
 
-      parameter_offset o;
-      o.first = clause_.size ();
+        // We don't want extra spaces after '(' as well as before ','
+        // and ')'.
+        //
+        if (last != ' ' && last != '(' &&
+            first != ' ' && first != ',' && first != ')')
+          s += ' ';
 
-      ostringstream ss;
-      ss << parameters_.size () + 1;
-      clause_ += '$' + ss.str ();
+        s += q;
+      }
+      else
+        clause_.push_back (clause_part (k, q));
+    }
 
-      o.second = clause_.size ();
-      parameter_offsets_.push_back (o);
+    void query::
+    add (details::shared_ptr<query_param> p)
+    {
+      clause_.push_back (clause_part (clause_part::param));
 
       parameters_.push_back (p);
       bind_.push_back (bind ());
@@ -288,17 +249,67 @@ namespace odb
       return native_binding_;
     }
 
-    std::string query::
-    clause () const
+    string query::
+    clause (string const& table) const
     {
-      if (clause_.empty () ||
-          clause_.compare (0, 6, "WHERE ") == 0 ||
-          clause_.compare (0, 9, "ORDER BY ") == 0 ||
-          clause_.compare (0, 9, "GROUP BY ") == 0 ||
-          clause_.compare (0, 7, "HAVING ") == 0)
-        return clause_;
+      string r;
+      size_t param (1);
+
+      for (clause_type::const_iterator i (clause_.begin ()),
+             end (clause_.end ()); i != end; ++i)
+      {
+        char last (!r.empty () ? r[r.size () - 1] : ' ');
+
+        switch (i->kind)
+        {
+        case clause_part::column:
+          {
+            if (last != ' ' && last != '(')
+              r += ' ';
+
+            if (i->part[0] == '.')
+              r += table;
+
+            r += i->part;
+            break;
+          }
+        case clause_part::param:
+          {
+            if (last != ' ' && last != '(')
+              r += ' ';
+
+            ostringstream os;
+            os << param++;
+            r += '$';
+            r += os.str ();
+            break;
+          }
+        case clause_part::native:
+          {
+            // We don't want extra spaces after '(' as well as before ','
+            // and ')'.
+            //
+            const string& p (i->part);
+            char first (!p.empty () ? p[0] : ' ');
+
+            if (last != ' ' && last != '(' &&
+                first != ' ' && first != ',' && first != ')')
+              r += ' ';
+
+            r += p;
+            break;
+          }
+        }
+      }
+
+      if (r.empty () ||
+          r.compare (0, 6, "WHERE ") == 0 ||
+          r.compare (0, 9, "ORDER BY ") == 0 ||
+          r.compare (0, 9, "GROUP BY ") == 0 ||
+          r.compare (0, 7, "HAVING ") == 0)
+        return r;
       else
-        return "WHERE " + clause_;
+        return "WHERE " + r;
     }
   }
 }
diff --git a/odb/pgsql/query.hxx b/odb/pgsql/query.hxx
index 9e0a7d1..96fa126 100644
--- a/odb/pgsql/query.hxx
+++ b/odb/pgsql/query.hxx
@@ -89,15 +89,33 @@ namespace odb
     class LIBODB_PGSQL_EXPORT query
     {
     public:
+      struct clause_part
+      {
+        enum kind_type
+        {
+          column,
+          param,
+          native
+        };
+
+        clause_part (kind_type k): kind (k) {}
+        clause_part (kind_type k, const std::string& p): kind (k), part (p) {}
+
+        kind_type kind;
+        std::string part;
+      };
+
       query ()
         : binding_ (0, 0), native_binding_ (0, 0, 0, 0)
       {
       }
 
       explicit
-      query (const std::string& q)
-        : clause_ (q), binding_ (0, 0), native_binding_ (0, 0, 0, 0)
+      query (const std::string& q,
+             clause_part::kind_type k = clause_part::native)
+        : binding_ (0, 0), native_binding_ (0, 0, 0, 0)
       {
+        clause_.push_back (clause_part (k, q));
       }
 
       template <typename T>
@@ -126,7 +144,7 @@ namespace odb
 
     public:
       std::string
-      clause () const;
+      clause (std::string const& default_table) const;
 
       native_binding&
       parameters_binding () const;
@@ -165,12 +183,7 @@ namespace odb
       query&
       operator+= (const std::string& q)
       {
-        size_t n (clause_.size ());
-
-        if (n != 0 && clause_[n - 1] != ' ' && !q.empty () && q[0] != ' ')
-          clause_ += ' ';
-
-        clause_ += q;
+        append (q, clause_part::native);
         return *this;
       }
 
@@ -199,19 +212,20 @@ namespace odb
       void
       append (ref_bind<T>);
 
+      void
+      append (const std::string&, clause_part::kind_type);
+
     private:
       void
       add (details::shared_ptr<query_param>);
 
     private:
+      typedef std::vector<clause_part> clause_type;
       typedef std::vector<details::shared_ptr<query_param> > parameters_type;
 
-      std::string clause_;
+      clause_type clause_;
       parameters_type parameters_;
 
-      typedef std::pair<std::size_t, std::size_t> parameter_offset;
-      std::vector<parameter_offset> parameter_offsets_;
-
       mutable std::vector<bind> bind_;
       mutable binding binding_;
 
@@ -391,7 +405,7 @@ namespace odb
       query
       is_null () const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "IS NULL";
         return q;
       }
@@ -399,7 +413,7 @@ namespace odb
       query
       is_not_null () const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "IS NOT NULL";
         return q;
       }
@@ -435,7 +449,7 @@ namespace odb
       query
       equal (val_bind<T> v) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "=";
         q.append<T, ID> (v);
         return q;
@@ -452,7 +466,7 @@ namespace odb
       query
       equal (ref_bind<T> r) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "=";
         q.append<T, ID> (r);
         return q;
@@ -520,7 +534,7 @@ namespace odb
       query
       unequal (val_bind<T> v) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "!=";
         q.append<T, ID> (v);
         return q;
@@ -537,7 +551,7 @@ namespace odb
       query
       unequal (ref_bind<T> r) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "!=";
         q.append<T, ID> (r);
         return q;
@@ -605,7 +619,7 @@ namespace odb
       query
       less (val_bind<T> v) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "<";
         q.append<T, ID> (v);
         return q;
@@ -622,7 +636,7 @@ namespace odb
       query
       less (ref_bind<T> r) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "<";
         q.append<T, ID> (r);
         return q;
@@ -690,7 +704,7 @@ namespace odb
       query
       greater (val_bind<T> v) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += ">";
         q.append<T, ID> (v);
         return q;
@@ -707,7 +721,7 @@ namespace odb
       query
       greater (ref_bind<T> r) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += ">";
         q.append<T, ID> (r);
         return q;
@@ -775,7 +789,7 @@ namespace odb
       query
       less_equal (val_bind<T> v) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "<=";
         q.append<T, ID> (v);
         return q;
@@ -792,7 +806,7 @@ namespace odb
       query
       less_equal (ref_bind<T> r) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "<=";
         q.append<T, ID> (r);
         return q;
@@ -860,7 +874,7 @@ namespace odb
       query
       greater_equal (val_bind<T> v) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += ">=";
         q.append<T, ID> (v);
         return q;
@@ -877,7 +891,7 @@ namespace odb
       query
       greater_equal (ref_bind<T> r) const
       {
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += ">=";
         q.append<T, ID> (r);
         return q;
@@ -944,9 +958,9 @@ namespace odb
         //
         (void) (sizeof (type_instance<T> () == type_instance<T2> ()));
 
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "=";
-        q += c.name ();
+        q.append (c.name (), query::clause_part::column);
         return q;
       }
 
@@ -958,9 +972,9 @@ namespace odb
         //
         (void) (sizeof (type_instance<T> () != type_instance<T2> ()));
 
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "!=";
-        q += c.name ();
+        q.append (c.name (), query::clause_part::column);
         return q;
       }
 
@@ -972,9 +986,9 @@ namespace odb
         //
         (void) (sizeof (type_instance<T> () < type_instance<T2> ()));
 
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "<";
-        q += c.name ();
+        q.append (c.name (), query::clause_part::column);
         return q;
       }
 
@@ -986,9 +1000,9 @@ namespace odb
         //
         (void) (sizeof (type_instance<T> () > type_instance<T2> ()));
 
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += ">";
-        q += c.name ();
+        q.append (c.name (), query::clause_part::column);
         return q;
       }
 
@@ -1000,9 +1014,9 @@ namespace odb
         //
         (void) (sizeof (type_instance<T> () <= type_instance<T2> ()));
 
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += "<=";
-        q += c.name ();
+        q.append (c.name (), query::clause_part::column);
         return q;
       }
 
@@ -1014,9 +1028,9 @@ namespace odb
         //
         (void) (sizeof (type_instance<T> () >= type_instance<T2> ()));
 
-        query q (name_);
+        query q (name_, query::clause_part::column);
         q += ">=";
-        q += c.name ();
+        q.append (c.name (), query::clause_part::column);
         return q;
       }
 
@@ -1701,6 +1715,13 @@ namespace odb
         : object_traits<T>::query_type (qc)
     {
     }
+
+    std::string
+    clause () const
+    {
+      return object_traits<T>::query_type::clause (
+        object_traits<T>::table_name);
+    }
   };
 }
 
diff --git a/odb/pgsql/query.txx b/odb/pgsql/query.txx
index 7d80f2b..6fdc4fe 100644
--- a/odb/pgsql/query.txx
+++ b/odb/pgsql/query.txx
@@ -13,12 +13,14 @@ namespace odb
     template <database_type_id ID>
     query::
     query (const query_column<bool, ID>& c)
-        : clause_ (c.name ()), binding_ (0, 0), native_binding_ (0, 0, 0, 0)
+        : binding_ (0, 0), native_binding_ (0, 0, 0, 0)
     {
+      clause_.push_back (clause_part (clause_part::column, c.name ()));
+
       // Cannot use IS TRUE here since database type can be a non-
       // integral type.
       //
-      clause_ += " = ";
+      clause_.push_back (clause_part (clause_part::native, "="));
       append<bool, ID> (val_bind<bool> (true));
     }
 
@@ -28,7 +30,7 @@ namespace odb
     query query_column<T, ID>::
     in (const T& v1, const T& v2) const
     {
-      query q (name_);
+      query q (name_, query::clause_part::column);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1));
       q += ",";
@@ -41,7 +43,7 @@ namespace odb
     query query_column<T, ID>::
     in (const T& v1, const T& v2, const T& v3) const
     {
-      query q (name_);
+      query q (name_, query::clause_part::column);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1));
       q += ",";
@@ -56,7 +58,7 @@ namespace odb
     query query_column<T, ID>::
     in (const T& v1, const T& v2, const T& v3, const T& v4) const
     {
-      query q (name_);
+      query q (name_, query::clause_part::column);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1));
       q += ",";
@@ -73,7 +75,7 @@ namespace odb
     query query_column<T, ID>::
     in (const T& v1, const T& v2, const T& v3, const T& v4, const T& v5) const
     {
-      query q (name_);
+      query q (name_, query::clause_part::column);
       q += "IN (";
       q.append<T, ID> (val_bind<T> (v1));
       q += ",";
@@ -93,7 +95,7 @@ namespace odb
     query query_column<T, ID>::
     in_range (I begin, I end) const
     {
-      query q (name_);
+      query q (name_, query::clause_part::column);
       q += "IN (";
 
       for (I i (begin); i != end; ++i)
-- 
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