Committing patch [#23278] (by me)

This patch allows a user to pass binary data to LibLoad() to load a blend file from memory instead of a file path. I don't know how useful this will be for others, but I've used it so far for:
  * Decrypting .blend files and loading them without having to store the .blend on the hard drive
  * Pulling .blend data out of an archive and loading it (again skipping the hard drive)

So, it seems the biggest use for this is skipping a bit of file IO (and possibly some security problems).

Example usage:
import bge

with f as open('myfile.blend', 'rb'):
    data = f.read()

bge.logic.LibLoad('Name', 'Scene', data)

source/blender/blenloader/BLO_readfile.h

@@ -122,6 +122,19 @@ BLO_blendfiledata_free(
 BLO_blendhandle_from_file(
 	char *file);
 
+/**
+ * Open a blendhandle from memory.
+ *
+ * @param mem The data to load from.
+ * @param memsize The size of the data.
+ * @return A handle on success, or NULL on failure.
+ */
+
+	BlendHandle*
+BLO_blendhandle_from_memory(
+	void *mem,
+	int memsize);
+
 /**
  * Gets the names of all the datablocks in a file
  * of a certain type (ie. All the scene names in

source/blender/blenloader/intern/readblenentry.c

@@ -76,6 +76,15 @@ BlendHandle *BLO_blendhandle_from_file(char *file)
 	return bh;
 }
 
+BlendHandle *BLO_blendhandle_from_memory(void *mem, int memsize)
+{
+	BlendHandle *bh;
+
+	bh= (BlendHandle*)blo_openblendermemory(mem, memsize, NULL);
+
+	return bh;
+}
+
 void BLO_blendhandle_print_sizes(BlendHandle *bh, void *fp) 
 {
 	FileData *fd= (FileData*) bh;

source/gameengine/Converter/KX_BlenderSceneConverter.cpp

@@ -932,13 +932,28 @@ Main* KX_BlenderSceneConverter::GetMainDynamicPath(const char *path)
 	return NULL;
 }
 
-bool KX_BlenderSceneConverter::LinkBlendFile(const char *path, char *group, KX_Scene *scene_merge, char **err_str)
+bool KX_BlenderSceneConverter::LinkBlendFileMemory(void *data, int length, const char *path, char *group, KX_Scene *scene_merge, char **err_str)
+{
+	BlendHandle *bpy_openlib = BLO_blendhandle_from_memory(data, length);
+
+	// Error checking is done in LinkBlendFile
+	return LinkBlendFile(bpy_openlib, path, group, scene_merge, err_str);
+}
+
+bool KX_BlenderSceneConverter::LinkBlendFilePath(const char *path, char *group, KX_Scene *scene_merge, char **err_str)
+{
+	BlendHandle *bpy_openlib = BLO_blendhandle_from_file( (char *)path );
+
+	// Error checking is done in LinkBlendFile
+	return LinkBlendFile(bpy_openlib, path, group, scene_merge, err_str);
+}
+
+bool KX_BlenderSceneConverter::LinkBlendFile(BlendHandle *bpy_openlib, const char *path, char *group, KX_Scene *scene_merge, char **err_str)
 {
 	bContext *C;
 	Main *main_newlib; /* stored as a dynamic 'main' until we free it */
 	Main *main_tmp= NULL; /* created only for linking, then freed */
 	LinkNode *names = NULL;
-	BlendHandle *bpy_openlib = NULL;	/* ptr to the open .blend file */	
 	int idcode= BKE_idcode_from_name(group);
 	short flag= 0; /* dont need any special options */
 	ReportList reports;
@@ -956,7 +971,6 @@ bool KX_BlenderSceneConverter::LinkBlendFile(const char *path, char *group, KX_S
 		return false;
 	}
 
-	bpy_openlib = BLO_blendhandle_from_file( (char *)path );
 	if(bpy_openlib==NULL) {
 		snprintf(err_local, sizeof(err_local), "could not open blendfile \"%s\"\n", path);
 		*err_str= err_local;

source/gameengine/Converter/KX_BlenderSceneConverter.h

@@ -142,7 +142,9 @@ public:
 	struct Main*		  GetMainDynamicPath(const char *path);
 	vector<struct Main*> &GetMainDynamic();
 	
-	bool LinkBlendFile(const char *path, char *group, KX_Scene *scene_merge, char **err_str);
+	bool LinkBlendFileMemory(void *data, int length, const char *path, char *group, KX_Scene *scene_merge, char **err_str);
+	bool LinkBlendFilePath(const char *path, char *group, KX_Scene *scene_merge, char **err_str);
+	bool LinkBlendFile(struct BlendHandle *bpy_openlib, const char *path, char *group, KX_Scene *scene_merge, char **err_str);
 	bool MergeScene(KX_Scene *to, KX_Scene *from);
 	RAS_MeshObject *ConvertMeshSpecial(KX_Scene* kx_scene, Main *maggie, const char *name);
 	bool FreeBlendFile(struct Main *maggie);

source/gameengine/Ketsji/KX_PythonInit.cpp

@@ -626,13 +626,28 @@ static PyObject *gLibLoad(PyObject*, PyObject* args)
 	KX_Scene *kx_scene= gp_KetsjiScene;
 	char *path;
 	char *group;
+	Py_buffer py_buffer;
+	py_buffer.buf = NULL;
 	char *err_str= NULL;
 	
-	if (!PyArg_ParseTuple(args,"ss:LibLoad",&path, &group))
+	if (!PyArg_ParseTuple(args,"ss|y*:LibLoad",&path, &group, &py_buffer))
 		return NULL;
 
-	if(kx_scene->GetSceneConverter()->LinkBlendFile(path, group, kx_scene, &err_str)) {
-		Py_RETURN_TRUE;
+	if (!py_buffer.buf)
+	{
+		if(kx_scene->GetSceneConverter()->LinkBlendFilePath(path, group, kx_scene, &err_str)) {
+			Py_RETURN_TRUE;
+		}
+	}
+	else
+	{
+
+		if(kx_scene->GetSceneConverter()->LinkBlendFileMemory(py_buffer.buf, py_buffer.len, path, group, kx_scene, &err_str))	{
+			PyBuffer_Release(&py_buffer);
+			Py_RETURN_TRUE;
+		}
+
+		PyBuffer_Release(&py_buffer);
 	}
 	
 	if(err_str) {

source/gameengine/PyDoc/bge.logic.rst

@@ -173,14 +173,16 @@ General functions
 
    Restarts the current game by reloading the .blend file (the last saved version, not what is currently running).
    
-.. function:: LibLoad(blend, type)
+.. function:: LibLoad(blend, type, data)
    
    Converts the all of the datablocks of the given type from the given blend.
    
-   :arg blend: The path to the blend file
+   :arg blend: The path to the blend file (or the name to use for the library if data is supplied)
    :type blend: string
    :arg type: The datablock type (currently only "Scene" and "Mesh" are supported)
    :type type: string
+   :arg data: Binary data from a blend file (optional)
+   :type data: bytes
    
 .. function:: LibNew(name, type, data)