8 files changed, 243 insertions, 0 deletions
diff --git a/contrib/ltree_plpython/.gitignore b/contrib/ltree_plpython/.gitignore
new file mode 100644
index 0000000..5dcb3ff
--- /dev/null
+++ b/contrib/ltree_plpython/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/ltree_plpython/Makefile b/contrib/ltree_plpython/Makefile
new file mode 100644
index 0000000..406d278
--- /dev/null
+++ b/contrib/ltree_plpython/Makefile
@@ -0,0 +1,39 @@
+# contrib/ltree_plpython/Makefile
+
+MODULE_big = ltree_plpython$(python_majorversion)
+OBJS = \
+	$(WIN32RES) \
+	ltree_plpython.o
+PGFILEDESC = "ltree_plpython - ltree transform for plpython"
+
+EXTENSION = ltree_plpython3u
+DATA = ltree_plpython3u--1.0.sql
+
+REGRESS = ltree_plpython
+
+PG_CPPFLAGS = $(python_includespec) -DPLPYTHON_LIBNAME='"plpython$(python_majorversion)"'
+
+ifdef USE_PGXS
+PG_CPPFLAGS += -I$(includedir_server)/extension
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+PG_CPPFLAGS += -I$(top_srcdir)/src/pl/plpython -I$(top_srcdir)/contrib
+subdir = contrib/ltree_plpython
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
+
+# We must link libpython explicitly
+ifeq ($(PORTNAME), win32)
+# ... see silliness in plpython Makefile ...
+SHLIB_LINK_INTERNAL += $(sort $(wildcard ../../src/pl/plpython/libpython*.a))
+else
+rpathdir = $(python_libdir)
+SHLIB_LINK += $(python_libspec) $(python_additional_libs)
+endif
+
+REGRESS_OPTS += --load-extension=ltree
+EXTRA_INSTALL += contrib/ltree
diff --git a/contrib/ltree_plpython/expected/ltree_plpython.out b/contrib/ltree_plpython/expected/ltree_plpython.out
new file mode 100644
index 0000000..bd32541
--- /dev/null
+++ b/contrib/ltree_plpython/expected/ltree_plpython.out
@@ -0,0 +1,43 @@
+CREATE EXTENSION ltree_plpython3u CASCADE;
+NOTICE:  installing required extension "plpython3u"
+CREATE FUNCTION test1(val ltree) RETURNS int
+LANGUAGE plpython3u
+TRANSFORM FOR TYPE ltree
+AS $$
+plpy.info(repr(val))
+return len(val)
+$$;
+SELECT test1('aa.bb.cc'::ltree);
+INFO:  ['aa', 'bb', 'cc']
+ test1 
+-------
+     3
+(1 row)
+
+CREATE FUNCTION test1n(val ltree) RETURNS int
+LANGUAGE plpython3u
+TRANSFORM FOR TYPE ltree
+AS $$
+plpy.info(repr(val))
+return len(val)
+$$;
+SELECT test1n('aa.bb.cc'::ltree);
+INFO:  ['aa', 'bb', 'cc']
+ test1n 
+--------
+      3
+(1 row)
+
+CREATE FUNCTION test2() RETURNS ltree
+LANGUAGE plpython3u
+TRANSFORM FOR TYPE ltree
+AS $$
+return ['foo', 'bar', 'baz']
+$$;
+-- plpython to ltree is not yet implemented, so this will fail,
+-- because it will try to parse the Python list as an ltree input
+-- string.
+SELECT test2();
+ERROR:  ltree syntax error at character 1
+CONTEXT:  while creating return value
+PL/Python function "test2"
diff --git a/contrib/ltree_plpython/ltree_plpython.c b/contrib/ltree_plpython/ltree_plpython.c
new file mode 100644
index 0000000..ac159ea
--- /dev/null
+++ b/contrib/ltree_plpython/ltree_plpython.c
@@ -0,0 +1,58 @@
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "ltree/ltree.h"
+#include "plpython.h"
+
+PG_MODULE_MAGIC;
+
+/* Linkage to functions in plpython module */
+typedef PyObject *(*PLyUnicode_FromStringAndSize_t) (const char *s, Py_ssize_t size);
+static PLyUnicode_FromStringAndSize_t PLyUnicode_FromStringAndSize_p;
+
+
+/*
+ * Module initialize function: fetch function pointers for cross-module calls.
+ */
+void
+_PG_init(void)
+{
+	/* Asserts verify that typedefs above match original declarations */
+	AssertVariableIsOfType(&PLyUnicode_FromStringAndSize, PLyUnicode_FromStringAndSize_t);
+	PLyUnicode_FromStringAndSize_p = (PLyUnicode_FromStringAndSize_t)
+		load_external_function("$libdir/" PLPYTHON_LIBNAME, "PLyUnicode_FromStringAndSize",
+							   true, NULL);
+}
+
+
+/* These defines must be after the module init function */
+#define PLyUnicode_FromStringAndSize PLyUnicode_FromStringAndSize_p
+
+
+PG_FUNCTION_INFO_V1(ltree_to_plpython);
+
+Datum
+ltree_to_plpython(PG_FUNCTION_ARGS)
+{
+	ltree	   *in = PG_GETARG_LTREE_P(0);
+	int			i;
+	PyObject   *list;
+	ltree_level *curlevel;
+
+	list = PyList_New(in->numlevel);
+	if (!list)
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of memory")));
+
+	curlevel = LTREE_FIRST(in);
+	for (i = 0; i < in->numlevel; i++)
+	{
+		PyList_SetItem(list, i, PLyUnicode_FromStringAndSize(curlevel->name, curlevel->len));
+		curlevel = LEVEL_NEXT(curlevel);
+	}
+
+	PG_FREE_IF_COPY(in, 0);
+
+	return PointerGetDatum(list);
+}
diff --git a/contrib/ltree_plpython/ltree_plpython3u--1.0.sql b/contrib/ltree_plpython/ltree_plpython3u--1.0.sql
new file mode 100644
index 0000000..09ada3c
--- /dev/null
+++ b/contrib/ltree_plpython/ltree_plpython3u--1.0.sql
@@ -0,0 +1,12 @@
+/* contrib/ltree_plpython/ltree_plpython3u--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION ltree_plpython3u" to load this file. \quit
+
+CREATE FUNCTION ltree_to_plpython3(val internal) RETURNS internal
+LANGUAGE C STRICT IMMUTABLE
+AS 'MODULE_PATHNAME', 'ltree_to_plpython';
+
+CREATE TRANSFORM FOR ltree LANGUAGE plpython3u (
+    FROM SQL WITH FUNCTION ltree_to_plpython3(internal)
+);
diff --git a/contrib/ltree_plpython/ltree_plpython3u.control b/contrib/ltree_plpython/ltree_plpython3u.control
new file mode 100644
index 0000000..96c9764
--- /dev/null
+++ b/contrib/ltree_plpython/ltree_plpython3u.control
@@ -0,0 +1,6 @@
+# ltree_plpython3u extension
+comment = 'transform between ltree and plpython3u'
+default_version = '1.0'
+module_pathname = '$libdir/ltree_plpython3'
+relocatable = true
+requires = 'ltree,plpython3u'
diff --git a/contrib/ltree_plpython/meson.build b/contrib/ltree_plpython/meson.build
new file mode 100644
index 0000000..d6c1a25
--- /dev/null
+++ b/contrib/ltree_plpython/meson.build
@@ -0,0 +1,45 @@
+# Copyright (c) 2022-2023, PostgreSQL Global Development Group
+
+if not python3_dep.found()
+  subdir_done()
+endif
+
+ltree_plpython_sources = files(
+  'ltree_plpython.c',
+)
+
+if host_system == 'windows'
+  ltree_plpython_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'ltree_plpython3',
+    '--FILEDESC', 'ltree_plpython - ltree transform for plpython',])
+endif
+
+ltree_plpython = shared_module('ltree_plpython3',
+  ltree_plpython_sources,
+  include_directories: [plpython_inc, ltree_inc],
+  c_args: ['-DPLPYTHON_LIBNAME="plpython3"'],
+  kwargs: contrib_mod_args + {
+    'dependencies': [python3_dep, contrib_mod_args['dependencies']],
+  },
+)
+contrib_targets += ltree_plpython
+
+install_data(
+  'ltree_plpython3u--1.0.sql',
+  'ltree_plpython3u.control',
+  kwargs: contrib_data_args,
+)
+
+ltree_plpython_regress = [
+  'ltree_plpython'
+]
+
+tests += {
+  'name': 'ltree_plpython',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': ltree_plpython_regress,
+    'regress_args': ['--load-extension=ltree'],
+  },
+}
diff --git a/contrib/ltree_plpython/sql/ltree_plpython.sql b/contrib/ltree_plpython/sql/ltree_plpython.sql
new file mode 100644
index 0000000..0b8d283
--- /dev/null
+++ b/contrib/ltree_plpython/sql/ltree_plpython.sql
@@ -0,0 +1,36 @@
+CREATE EXTENSION ltree_plpython3u CASCADE;
+
+
+CREATE FUNCTION test1(val ltree) RETURNS int
+LANGUAGE plpython3u
+TRANSFORM FOR TYPE ltree
+AS $$
+plpy.info(repr(val))
+return len(val)
+$$;
+
+SELECT test1('aa.bb.cc'::ltree);
+
+
+CREATE FUNCTION test1n(val ltree) RETURNS int
+LANGUAGE plpython3u
+TRANSFORM FOR TYPE ltree
+AS $$
+plpy.info(repr(val))
+return len(val)
+$$;
+
+SELECT test1n('aa.bb.cc'::ltree);
+
+
+CREATE FUNCTION test2() RETURNS ltree
+LANGUAGE plpython3u
+TRANSFORM FOR TYPE ltree
+AS $$
+return ['foo', 'bar', 'baz']
+$$;
+
+-- plpython to ltree is not yet implemented, so this will fail,
+-- because it will try to parse the Python list as an ltree input
+-- string.
+SELECT test2();