Fix github issue #49 (#187)

* Fix github issue #49

pg_fdw was not working with PG11 because the layout
of TupleDesc has changed.  Return an array of
FormData_pg_attribute instead of an array of
points to them.

* replace tab with space to make clippy happy.

* formatting fixes for cargo fmt

* Fix formatting for cargo fmt

Cargo.toml

@@ -8,7 +8,7 @@ members = [
     "examples/adding",
 # Examples disabled because FDW support broken with PostgreSQL 11+.
 # See https://github.com/bluejekyll/pg-extend-rs/issues/49
-#    "examples/fdw",
+    "examples/fdw",
 #    "examples/fdw-rw",
     "examples/logging",
     "examples/memory_context",

examples/fdw/src/lib.rs

@@ -8,7 +8,7 @@
 extern crate pg_extend;
 extern crate pg_extern_attr;
 
-use pg_extend::pg_fdw::{ForeignData, ForeignRow, OptionMap, ForeignTableMetadata};
+use pg_extend::pg_fdw::{ForeignData, ForeignRow, ForeignTableMetadata, OptionMap};
 use pg_extend::{pg_datum, pg_magic, pg_type};
 use pg_extern_attr::pg_foreignwrapper;
 

integration-tests/tests/fdw.rs

@@ -11,7 +11,6 @@ use integration_tests::*;
 // FDW tests disabled because it's broken with PostgreSQL 11+.
 // See See https://github.com/bluejekyll/pg-extend-rs/issues/49
 #[test]
-#[ignore] // this test is currently broken
 fn test_fdw() {
     test_in_db("fdw", |mut conn| {
         conn.batch_execute(

pg-extend/src/pg_fdw.rs

@@ -306,26 +306,30 @@ impl<T: ForeignData> ForeignWrapper<T> {
         let mut t = HashMap::new();
 
         for i in 0..(attrs.len().min(data.len())) {
-            let name = Self::name_to_string(unsafe { (*attrs[i]).attname });
+            let name = Self::name_to_string((attrs[i]).attname);
             let data = unsafe { pg_datum::PgDatum::from_raw(memory_context, data[i], isnull[i]) };
             t.insert(name, data);
         }
 
         t
     }
 
-    unsafe fn tupdesc_attrs(tupledesc: &pg_sys::tupleDesc) -> &[pg_sys::Form_pg_attribute] {
+    unsafe fn tupdesc_attrs(tupledesc: &pg_sys::tupleDesc) -> &[pg_sys::FormData_pg_attribute] {
         #[cfg(feature = "postgres-11")]
         #[allow(clippy::cast_ptr_alignment)]
-        let attrs = (*tupledesc).attrs.as_ptr() as *const _;
+        {
+            let attrs = (*tupledesc).attrs.as_ptr();
+            std::slice::from_raw_parts(attrs, (*tupledesc).natts as usize)
+        }
         #[cfg(not(feature = "postgres-11"))]
-        let attrs = (*tupledesc).attrs;
-
-        std::slice::from_raw_parts(attrs, (*tupledesc).natts as usize)
+        {
+            let attrs = (*tupledesc).attrs;
+            std::slice::from_raw_parts(*attrs, (*tupledesc).natts as usize)
+        }
     }
 
     /// Retrieve next row from the result set, or clear tuple slot to indicate
-    ///	EOF.
+    /// EOF.
     /// Fetch one row from the foreign
     ///  (the node's ScanTupleSlot should be used for this purpose).
     ///  Return NULL if no more rows are available.
@@ -351,7 +355,7 @@ impl<T: ForeignData> ForeignWrapper<T> {
             let mut isnull = vec![pgbool!(true); attrs.len()];
             for (i, pattr) in attrs.iter().enumerate() {
                 // TODO: There must be a better way to do this?
-                let result = Self::get_field(&memory_context, &(**pattr), &(*row));
+                let result = Self::get_field(&memory_context, &(*pattr), &(*row));
                 match result {
                     Err(err) => {
                         warn!("{}", err);
@@ -408,11 +412,11 @@ impl<T: ForeignData> ForeignWrapper<T> {
 
         if let Some(keys) = T::index_columns(&table_metadata) {
             // Build a map of column names to attributes and column index
-            let attrs: HashMap<String, (&pg_sys::Form_pg_attribute, usize)> =
+            let attrs: HashMap<String, (&pg_sys::FormData_pg_attribute, usize)> =
                 Self::tupdesc_attrs(&*(*target_relation).rd_att)
                     .iter()
                     .enumerate()
-                    .map(|(idx, rel)| (Self::name_to_string((**rel).attname), (rel, idx)))
+                    .map(|(idx, rel)| (Self::name_to_string((rel).attname), (rel, idx)))
                     .collect();
 
             for key in keys {
@@ -428,8 +432,8 @@ impl<T: ForeignData> ForeignWrapper<T> {
                 let var = pg_sys::makeVar(
                     (*parsetree).resultRelation as u32,
                     *idx as i16 + 1, // points to the position in the tuple, 1-indexed
-                    (*attr).atttypid,
-                    (*attr).atttypmod,
+                    (attr).atttypid,
+                    (attr).atttypmod,
                     0 as pg_sys::Oid, // InvalidOid
                     0,
                 );