Get rid of libpq-fe.h inclusion in public headers

The problem with libpq-fe.h is that it is installed in unpredictable
places on different platforms. As a result, a user that uses ODB with
PostgreSQL (and who doesn't really know or care about libpq) is forced
to make sure their application is able to find and include libpq-fe.h
correctly.

Luckily for us, we only use a handful of libpq pointers in public
headers and the workaround is to forward declare them and use that
instead of including libpq-fe.h (which is instead included in source
files).

9 files changed, 77 insertions, 25 deletions

diff --git a/odb/pgsql/connection.cxx b/odb/pgsql/connection.cxx
index b4790b0..f65cba4 100644
--- a/odb/pgsql/connection.cxx
+++ b/odb/pgsql/connection.cxx
@@ -7,6 +7,8 @@
 #include <cstring> // std::strcmp
 #include <string>
 
+#include <libpq-fe.h>
+
 #include <odb/pgsql/database.hxx>
 #include <odb/pgsql/connection.hxx>
 #include <odb/pgsql/error.hxx>
diff --git a/odb/pgsql/connection.hxx b/odb/pgsql/connection.hxx
index 4793248..6914d5b 100644
--- a/odb/pgsql/connection.hxx
+++ b/odb/pgsql/connection.hxx
@@ -11,14 +11,13 @@
 #include <vector>
 #include <memory> // std::auto_ptr
 
-#include <libpq-fe.h>
-
 #include <odb/forward.hxx>
 
 #include <odb/details/shared-ptr.hxx>
 
 #include <odb/pgsql/version.hxx>
 #include <odb/pgsql/forward.hxx>
+#include <odb/pgsql/pgsql-fwd.hxx> // PGconn
 
 #include <odb/pgsql/details/export.hxx>
 
diff --git a/odb/pgsql/container-statements.hxx b/odb/pgsql/container-statements.hxx
index a1a0e66..252eb77 100644
--- a/odb/pgsql/container-statements.hxx
+++ b/odb/pgsql/container-statements.hxx
@@ -16,6 +16,7 @@
 #include <odb/pgsql/version.hxx>
 #include <odb/pgsql/binding.hxx>
 #include <odb/pgsql/statement.hxx>
+#include <odb/pgsql/pgsql-fwd.hxx> // Oid
 #include <odb/pgsql/pgsql-oid.hxx>
 #include <odb/pgsql/details/export.hxx>
 
diff --git a/odb/pgsql/error.hxx b/odb/pgsql/error.hxx
index 139a33c..287b45a 100644
--- a/odb/pgsql/error.hxx
+++ b/odb/pgsql/error.hxx
@@ -11,7 +11,6 @@
 #include <libpq-fe.h>
 
 #include <odb/pgsql/version.hxx>
-
 #include <odb/pgsql/details/export.hxx>
 
 namespace odb
@@ -28,8 +27,7 @@ namespace odb
     // allocation error.
     //
     LIBODB_PGSQL_EXPORT void
-    translate_error (connection& c,
-                     PGresult* r);
+    translate_error (connection& c, PGresult* r);
 
     // Return true if the PGresult is in an error state. If both s and r are
     // non-null, the pointed to value will be populated with the result status.
diff --git a/odb/pgsql/pgsql-fwd.hxx b/odb/pgsql/pgsql-fwd.hxx
new file mode 100644
index 0000000..45f085d
--- /dev/null
+++ b/odb/pgsql/pgsql-fwd.hxx
@@ -0,0 +1,21 @@
+// file      : odb/pgsql/pgsql-fwd.hxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : Copyright (c) 2005-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_PGSQL_PGSQL_FWD_HXX
+#define ODB_PGSQL_PGSQL_FWD_HXX
+
+#include <odb/pre.hxx>
+
+// Forward declaration for some of the types defined in libpq-fe.h. This
+// allows us to avoid having to include libpq-fe.h in public headers.
+//
+typedef unsigned int Oid;
+
+typedef struct pg_conn PGconn;
+typedef struct pg_result PGresult;
+
+#include <odb/post.hxx>
+
+#endif // ODB_PGSQL_PGSQL_FWD_HXX
diff --git a/odb/pgsql/pgsql-types.hxx b/odb/pgsql/pgsql-types.hxx
index 1d83b9f..2ebbc42 100644
--- a/odb/pgsql/pgsql-types.hxx
+++ b/odb/pgsql/pgsql-types.hxx
@@ -10,7 +10,7 @@
 
 #include <cstddef>  // std::size_t
 
-typedef unsigned int Oid;
+#include <odb/pgsql/pgsql-fwd.hxx> // Oid
 
 namespace odb
 {
diff --git a/odb/pgsql/result-ptr.hxx b/odb/pgsql/result-ptr.hxx
index 4cfe58d..2c5ee89 100644
--- a/odb/pgsql/result-ptr.hxx
+++ b/odb/pgsql/result-ptr.hxx
@@ -14,6 +14,12 @@
 
 #include <odb/pgsql/details/export.hxx>
 
+//
+// Note: do not include this header into public headers (i.e., those
+// that may be included, directly or indirectly, by user code) because
+// it includes libpq-fe.h
+//
+
 namespace odb
 {
   namespace pgsql
@@ -47,6 +53,14 @@ namespace odb
         r_ = r;
       }
 
+      PGresult*
+      release ()
+      {
+        PGresult* r (r_);
+        r_ = 0;
+        return r;
+      }
+
     private:
       result_ptr (const result_ptr&);
       result_ptr& operator= (const result_ptr&);
diff --git a/odb/pgsql/statement.cxx b/odb/pgsql/statement.cxx
index dde67c9..a9c7d9b 100644
--- a/odb/pgsql/statement.cxx
+++ b/odb/pgsql/statement.cxx
@@ -7,11 +7,14 @@
 #include <cassert>
 #include <sstream> // istringstream
 
+#include <libpq-fe.h>
+
 #include <odb/exceptions.hxx> // object_not_persistent
 
 #include <odb/pgsql/statement.hxx>
 #include <odb/pgsql/connection.hxx>
 #include <odb/pgsql/transaction.hxx>
+#include <odb/pgsql/result-ptr.hxx>
 #include <odb/pgsql/error.hxx>
 
 #include <odb/pgsql/details/endian-traits.hxx>
@@ -290,6 +293,8 @@ namespace odb
     select_statement::
     ~select_statement ()
     {
+      if (result_ != 0)
+        PQclear (result_);
     }
 
     select_statement::
@@ -305,6 +310,7 @@ namespace odb
           cond_ (&cond),
           native_cond_ (native_cond),
           data_ (data),
+          result_ (0),
           row_count_ (0),
           current_row_ (0)
 
@@ -323,6 +329,7 @@ namespace odb
           cond_ (0),
           native_cond_ (native_cond),
           data_ (data),
+          result_ (0),
           row_count_ (0),
           current_row_ (0)
 
@@ -332,32 +339,45 @@ namespace odb
     void select_statement::
     execute ()
     {
-      result_.reset ();
+      if (result_ != 0)
+      {
+        PQclear (result_);
+        result_ = 0;
+      }
 
       if (cond_ != 0)
         bind_param (native_cond_, *cond_);
 
-      result_.reset (PQexecPrepared (conn_.handle (),
-                                     name_.c_str (),
-                                     native_cond_.count,
-                                     native_cond_.values,
-                                     native_cond_.lengths,
-                                     native_cond_.formats,
-                                     1));
+      // Use temporary result_ptr to guarantee exception safety.
+      //
+      result_ptr r (PQexecPrepared (conn_.handle (),
+                                    name_.c_str (),
+                                    native_cond_.count,
+                                    native_cond_.values,
+                                    native_cond_.lengths,
+                                    native_cond_.formats,
+                                    1));
 
-      PGresult* h (result_.get ());
+      PGresult* h (r.get ());
 
       if (!is_good_result (h))
         translate_error (conn_, h);
 
       row_count_ = static_cast<size_t> (PQntuples (h));
       current_row_ = 0;
+
+      result_ = r.release ();
     }
 
     void select_statement::
     free_result ()
     {
-      result_.reset ();
+      if (result_ != 0)
+      {
+        PQclear (result_);
+        result_ = 0;
+      }
+
       row_count_ = 0;
       current_row_ = 0;
     }
@@ -377,11 +397,10 @@ namespace odb
       if (current_row_ > row_count_)
         return no_data;
 
-      PGresult* h (result_.get ());
-
       assert (current_row_ > 0);
-      return bind_result (data_.bind, data_.count, h, current_row_ - 1) ?
-        success : truncated;
+      return bind_result (data_.bind, data_.count, result_, current_row_ - 1)
+        ? success
+        : truncated;
     }
 
     void select_statement::
@@ -392,7 +411,7 @@ namespace odb
 
       if (!bind_result (data_.bind,
                         data_.count,
-                        result_.get (),
+                        result_,
                         current_row_ - 1,
                         true))
         assert (false);
diff --git a/odb/pgsql/statement.hxx b/odb/pgsql/statement.hxx
index e248b07..3a25f5e 100644
--- a/odb/pgsql/statement.hxx
+++ b/odb/pgsql/statement.hxx
@@ -11,13 +11,11 @@
 #include <string>
 #include <cstddef>  // std::size_t
 
-#include <libpq-fe.h>
-
 #include <odb/details/shared-ptr.hxx>
 
 #include <odb/pgsql/version.hxx>
 #include <odb/pgsql/binding.hxx>
-#include <odb/pgsql/result-ptr.hxx>
+#include <odb/pgsql/pgsql-fwd.hxx>
 
 #include <odb/pgsql/details/export.hxx>
 
@@ -159,7 +157,7 @@ namespace odb
 
       binding& data_;
 
-      result_ptr result_;
+      PGresult* result_;
       std::size_t row_count_;
       std::size_t current_row_;
     };