PyAPI: API for selectively writing data-blocks

Useful for writing asset-libraries to a file, eg.

`bpy.data.libraries.write(filepath, datablocks, relative_remap=False, fake_user=False)`

5 files changed, 225 insertions, 11 deletions

diff --git a/source/blender/python/intern/CMakeLists.txt b/source/blender/python/intern/CMakeLists.txt
index 8ce94b8006f..fa7c94025f7 100644
--- a/source/blender/python/intern/CMakeLists.txt
+++ b/source/blender/python/intern/CMakeLists.txt
@@ -61,7 +61,8 @@ set(SRC
 	bpy_interface.c
 	bpy_interface_atexit.c
 	bpy_intern_string.c
-	bpy_library.c
+	bpy_library_load.c
+	bpy_library_write.c
 	bpy_operator.c
 	bpy_operator_wrap.c
 	bpy_path.c
diff --git a/source/blender/python/intern/bpy.c b/source/blender/python/intern/bpy.c
index 930950a6600..c09b39139c2 100644
--- a/source/blender/python/intern/bpy.c
+++ b/source/blender/python/intern/bpy.c
@@ -322,7 +322,9 @@ void BPy_init_modules(void)
 	PyModule_AddObject(mod, "types", BPY_rna_types());
 
 	/* needs to be first so bpy_types can run */
-	BPY_library_module(mod);
+	BPY_library_load_module(mod);
+	BPY_library_write_module(mod);
+
 	BPY_rna_id_collection_module(mod);
 
 	bpy_import_test("bpy_types");
diff --git a/source/blender/python/intern/bpy_library.h b/source/blender/python/intern/bpy_library.h
index 1b68007b704..c381a4206fa 100644
--- a/source/blender/python/intern/bpy_library.h
+++ b/source/blender/python/intern/bpy_library.h
@@ -27,6 +27,7 @@
 #ifndef __BPY_LIBRARY_H__
 #define __BPY_LIBRARY_H__
 
-int BPY_library_module(PyObject *);
+int BPY_library_load_module(PyObject *mod_par);
+int BPY_library_write_module(PyObject *mod_par);
 
 #endif  /* __BPY_LIBRARY_H__ */
diff --git a/source/blender/python/intern/bpy_library.c b/source/blender/python/intern/bpy_library_load.c
index dd1be67946b..a120e4886e0 100644
--- a/source/blender/python/intern/bpy_library.c
+++ b/source/blender/python/intern/bpy_library_load.c
@@ -15,12 +15,10 @@
  * along with this program; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  *
- * Contributor(s): Campbell Barton
- *
  * ***** END GPL LICENSE BLOCK *****
  */
 
-/** \file blender/python/intern/bpy_library.c
+/** \file blender/python/intern/bpy_library_load.c
  *  \ingroup pythonintern
  *
  * This file exposed blend file library appending/linking to python, typically
@@ -464,12 +462,13 @@ static PyObject *bpy_lib_dir(BPy_Library *self)
 }
 
 
-int BPY_library_module(PyObject *mod_par)
+int BPY_library_load_module(PyObject *mod_par)
 {
-	static PyMethodDef load_meth = {"load", (PyCFunction)bpy_lib_load,
-	                                METH_STATIC | METH_VARARGS | METH_KEYWORDS,
-	                                bpy_lib_load_doc};
-
+	static PyMethodDef load_meth = {
+		"load", (PyCFunction)bpy_lib_load,
+		METH_STATIC | METH_VARARGS | METH_KEYWORDS,
+		bpy_lib_load_doc,
+	};
 	PyModule_AddObject(mod_par, "_library_load", PyCFunction_New(&load_meth, NULL));
 
 	/* some compilers don't like accessing this directly, delay assignment */
diff --git a/source/blender/python/intern/bpy_library_write.c b/source/blender/python/intern/bpy_library_write.c
new file mode 100644
index 00000000000..255bb82ea10
--- /dev/null
+++ b/source/blender/python/intern/bpy_library_write.c
@@ -0,0 +1,211 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/intern/bpy_library_write.c
+ *  \ingroup pythonintern
+ *
+ * Python API for writing a set of data-blocks into a file.
+ * Useful for writing out asset-libraries, defines: `bpy.data.libraries.write(...)`.
+ */
+
+#include <Python.h>
+#include <stddef.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_utildefines.h"
+#include "BLI_string.h"
+#include "BLI_path_util.h"
+
+#include "BKE_library.h"
+#include "BKE_blender.h"
+#include "BKE_global.h"
+#include "BKE_main.h"
+#include "BKE_report.h"
+
+#include "RNA_types.h"
+
+#include "bpy_rna.h"
+#include "bpy_util.h"
+#include "bpy_library.h"
+
+#include "../generic/py_capi_utils.h"
+
+
+PyDoc_STRVAR(bpy_lib_write_doc,
+".. method:: write(filepath, datablocks, relative_remap=False, fake_user=False)\n"
+"\n"
+"   Write data-blocks into a blend file.\n"
+"\n"
+"   :arg filepath: The path to write the blend-file.\n"
+"   :type filepath: string\n"
+"   :arg datablocks: data-blocks (:class:`bpy.types.ID` instances).\n"
+"   :type datablocks: sequence\n"
+"   :arg relative_remap: When Truem, remap the paths relative to the current blend-file.\n"
+"   :type relative_remap: bool\n"
+"   :arg fake_user: When True, data-blocks will be written with fake-user flag enabled.\n"
+"   :type fake_user: bool\n"
+);
+static PyObject *bpy_lib_write(PyObject *UNUSED(self), PyObject *args, PyObject *kwds)
+{
+	static const char *kwlist[] = {
+		"filepath", "datablocks",
+		/* optional */
+		"relative_remap", "fake_user",
+		NULL,
+	};
+
+	/* args */
+	const char *filepath;
+	char filepath_abs[FILE_MAX];
+	PyObject *datablocks = NULL;
+	bool use_relative_remap = false, use_fake_user = false;
+
+	if (!PyArg_ParseTupleAndKeywords(
+	        args, kwds,
+	        "sO!|$O&O&:write", (char **)kwlist,
+	        &filepath,
+	        &PySet_Type, &datablocks,
+	        PyC_ParseBool, &use_relative_remap,
+	        PyC_ParseBool, &use_fake_user))
+	{
+		return NULL;
+	}
+
+	Main *bmain_src = G.main;
+	int write_flags = 0;
+
+	if (use_relative_remap) {
+		write_flags |= G_FILE_RELATIVE_REMAP;
+	}
+
+	BLI_strncpy(filepath_abs, filepath, FILE_MAX);
+	BLI_path_abs(filepath_abs, G.main->name);
+
+	BKE_blendfile_write_partial_begin(bmain_src);
+
+	/* array of ID's and backup any data we modify */
+	struct {
+		ID *id;
+		/* original values */
+		short id_flag;
+		short id_us;
+	} *id_store_array, *id_store;
+	int id_store_len = 0;
+
+	PyObject *ret;
+
+	/* collect all id data from the set and store in 'id_store_array' */
+	{
+		Py_ssize_t pos, hash;
+		PyObject *key;
+
+		id_store_array = MEM_mallocN(sizeof(*id_store_array) * PySet_Size(datablocks), __func__);
+		id_store = id_store_array;
+
+		pos = hash = 0;
+		while (_PySet_NextEntry(datablocks, &pos, &key, &hash)) {
+
+			if (!pyrna_id_FromPyObject(key, &id_store->id)) {
+				PyErr_Format(PyExc_TypeError,
+				             "Expected and ID type, not %.200s",
+				             Py_TYPE(key)->tp_name);
+				ret = NULL;
+				goto finally;
+			}
+			else {
+				id_store->id_flag = id_store->id->flag;
+				id_store->id_us = id_store->id->us;
+
+				if (use_fake_user) {
+					id_store->id->flag |= LIB_FAKEUSER;
+				}
+				id_store->id->us = 1;
+
+				BKE_blendfile_write_partial_tag_ID(id_store->id, true);
+
+				id_store_len += 1;
+				id_store++;
+			}
+		}
+	}
+
+	/* write blend */
+	int retval = 0;
+	ReportList reports;
+
+	BKE_reports_init(&reports, RPT_STORE);
+
+	retval = BKE_blendfile_write_partial(bmain_src, filepath_abs, write_flags, &reports);
+
+	/* cleanup state */
+	BKE_blendfile_write_partial_end(bmain_src);
+
+	if (retval) {
+		BKE_reports_print(&reports, RPT_ERROR_ALL);
+		BKE_reports_clear(&reports);
+		ret = Py_None;
+		Py_INCREF(ret);
+	}
+	else {
+		if (BPy_reports_to_error(&reports, PyExc_RuntimeError, true) == 0) {
+			PyErr_SetString(PyExc_RuntimeError, "Unknown error writing library data");
+		}
+		ret = NULL;
+	}
+
+
+finally:
+
+	/* clear all flags for ID's added to the store (may run on error too) */
+	id_store = id_store_array;
+
+	for (int i = 0; i < id_store_len; id_store++, i++) {
+
+
+		if (use_fake_user) {
+			if ((id_store->id_flag & LIB_FAKEUSER) == 0) {
+				id_store->id->flag &= ~LIB_FAKEUSER;
+			}
+		}
+
+		id_store->id->us = id_store->id_us;
+
+		BKE_blendfile_write_partial_tag_ID(id_store->id, false);
+	}
+
+	MEM_freeN(id_store_array);
+
+	return ret;
+}
+
+
+int BPY_library_write_module(PyObject *mod_par)
+{
+	static PyMethodDef write_meth = {
+		"write", (PyCFunction)bpy_lib_write,
+		METH_STATIC | METH_VARARGS | METH_KEYWORDS,
+		bpy_lib_write_doc,
+	};
+
+	PyModule_AddObject(mod_par, "_library_write", PyCFunction_New(&write_meth, NULL));
+
+	return 0;
+}