Avoid direct cross-module links in hstore_plperl and ltree_plpython, too.

Just turning the crank on the project started in commit d51924be8.
These cases turn out to be exact subsets of the boilerplate needed
for hstore_plpython.

Discussion: <2652.1475512158@sss.pgh.pa.us>

1 files changed, 29 insertions, 0 deletions

diff --git a/contrib/ltree_plpython/ltree_plpython.c b/contrib/ltree_plpython/ltree_plpython.c
index 26b7b3c275d..bdd462a91b9 100644
--- a/contrib/ltree_plpython/ltree_plpython.c
+++ b/contrib/ltree_plpython/ltree_plpython.c
@@ -1,10 +1,39 @@
 #include "postgres.h"
+
 #include "fmgr.h"
 #include "plpython.h"
 #include "ltree.h"
 
 PG_MODULE_MAGIC;
 
+extern void _PG_init(void);
+
+/* Linkage to functions in plpython module */
+#if PY_MAJOR_VERSION >= 3
+typedef PyObject *(*PLyUnicode_FromStringAndSize_t) (const char *s, Py_ssize_t size);
+static PLyUnicode_FromStringAndSize_t PLyUnicode_FromStringAndSize_p;
+#endif
+
+
+/*
+ * Module initialize function: fetch function pointers for cross-module calls.
+ */
+void
+_PG_init(void)
+{
+	/* Asserts verify that typedefs above match original declarations */
+#if PY_MAJOR_VERSION >= 3
+	AssertVariableIsOfType(&PLyUnicode_FromStringAndSize, PLyUnicode_FromStringAndSize_t);
+	PLyUnicode_FromStringAndSize_p = (PLyUnicode_FromStringAndSize_t)
+		load_external_function("$libdir/" PLPYTHON_LIBNAME, "PLyUnicode_FromStringAndSize",
+							   true, NULL);
+#endif
+}
+
+
+/* These defines must be after the module init function */
+#define PLyUnicode_FromStringAndSize PLyUnicode_FromStringAndSize_p
+
 
 PG_FUNCTION_INFO_V1(ltree_to_plpython);