getprop.py

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import ast
import traceback

import bpy
from bpy.props import StringProperty, BoolProperty, IntProperty, FloatProperty, FloatVectorProperty
from bpy.types import bpy_prop_array
import mathutils
from mathutils import Matrix, Vector, Euler, Quaternion, Color

from sverchok.node_tree import SverchCustomTreeNode

from sverchok.data_structure import Matrix_generate, updateNode, node_id

def parse_to_path(p):
    '''
    Create a path and can be looked up easily.
    Return an array of tuples with op type and value
    ops are:
    name - global name to use
    attr - attribute to get using getattr(obj,attr)
    key - key for accessing via obj[key]
    '''

    if isinstance(p, ast.Attribute):
        return parse_to_path(p.value)+[("attr", p.attr)] 
    elif isinstance(p, ast.Subscript):
        if isinstance(p.slice.value, ast.Num):
            return  parse_to_path(p.value) + [("key", p.slice.value.n)]
        elif isinstance(p.slice.value, ast.Str):
            return parse_to_path(p.value) + [("key", p.slice.value.s)]
    elif isinstance(p, ast.Name):
        return [("name", p.id)]
    else:
        raise NameError

def get_object(path):
    '''
    access the object speciefed from a path
    generated by parse_to_path
    will fail if path is invalid
    '''
    curr_object = globals()[path[0][1]]
    for t, value in path[1:]:
        if t == "attr":
            curr_object = getattr(curr_object, value)
        elif t == "key":
            curr_object = curr_object[value]
    return curr_object

def apply_alias(eval_str):
    '''
    apply standard aliases
    will raise error if it isn't an bpy path
    '''
    if not eval_str.startswith("bpy."):
        for alias, expanded in aliases.items():
            if eval_str.startswith(alias):
                eval_str = eval_str.replace(alias, expanded, 1)
                break
        if not eval_str.startswith("bpy."):
            raise NameError
    return eval_str

def wrap_output_data(tvar):
    '''
    create valid sverchok socket data from an object
    from ek node
    '''
    if isinstance(tvar, (Vector, Color)):
        data = [[tvar[:]]]
    elif isinstance(tvar, Matrix):
        data = [[r[:] for r in tvar[:]]]
    elif isinstance(tvar, (Euler, Quaternion)):
        tvar = tvar.to_matrix().to_4x4()
        data = [[r[:] for r in tvar[:]]]
    elif isinstance(tvar, list):
        data = [tvar]
    elif isinstance(tvar, (int, float)):
        data = [[tvar]]
    else:
        data = tvar
    return data

def assign_data(obj, data):
    '''
    assigns data to the object
    '''
    if isinstance(obj, (int, float)):
        # doesn't work
        obj = data[0][0]
    elif isinstance(obj, (Vector, Color)):
        obj[:] = data[0][0] 
    elif isinstance(obj, (Matrix, Euler, Quaternion)):
        mats = Matrix_generate(data)
        mat = mats[0]
        if isinstance(obj, Euler):
            eul = mat.to_euler(obj.order)
            obj[:] = eul
        elif isinstance(obj, Quaternion):
            quat = mat.to_quaternion()
            obj[:] = quat 
        else: #isinstance(obj, Matrix)
            obj[:] = mat
    else: # super optimistic guess
        obj[:] = type(obj)(data[0][0])


aliases = {
    "c": "bpy.context",
    "C" : "bpy.context",
    "scene": "bpy.context.scene",
    "data": "bpy.data",
    "D": "bpy.data",
    "objs": "bpy.data.objects",
    "mats": "bpy.data.materials",
    "M": "bpy.data.materials",
    "meshes": "bpy.data.meshes",
    "texts": "bpy.data.texts"
}

types = {
    int: "SvStringsSocket",
    float: "SvStringsSocket",
    str: "SvStringsSocket", # I WANT A PROPER TEXT SOCKET!!!
    mathutils.Vector: "SvVerticesSocket",
    mathutils.Color: "SvVerticesSocket",
    mathutils.Matrix: "SvMatrixSocket",
    mathutils.Euler: "SvMatrixSocket",
    mathutils.Quaternion: "SvMatrixSocket"
}


def secondary_type_assesment(item):
    """
    we can use this function to perform more granular attr/type identification
    """
    if isinstance(item, bpy_prop_array):
        if hasattr(item, "path_from_id") and item.path_from_id().endswith('color'):
            return "SvColorSocket"
    return None

class SvGetPropNode(SverchCustomTreeNode, bpy.types.Node):
    ''' Get Property '''
    bl_idname = 'SvGetPropNode'
    bl_label = 'Get Property'
    bl_icon = 'FORCE_VORTEX'
    sv_icon = 'SV_PROP_GET'
    is_animation_dependent = True
    is_scene_dependent = True

    bad_prop: BoolProperty(default=False)

    def verify_prop(self, context):
        try:
            obj = self.obj
        except:
            traceback.print_exc()
            self.bad_prop = True
            return

        self.bad_prop = False
        s_type = types.get(type(self.obj))
        
        if not s_type:
            s_type = secondary_type_assesment(self.obj)

        outputs = self.outputs
        if s_type and outputs:
            outputs[0].replace_socket(s_type)
        elif s_type:
            outputs.new(s_type, "Data")
      
        updateNode(self, context)

    prop_name: StringProperty(name='', update=verify_prop)

    @property
    def obj(self):
        eval_str = apply_alias(self.prop_name)
        ast_path = ast.parse(eval_str)
        path = parse_to_path(ast_path.body[0].value)
        return get_object(path)
    
    def sv_draw_buttons(self, context, layout):
        layout.alert = self.bad_prop
        layout.prop(self, "prop_name", text="")

    def process(self):
        # print(">> Get process is called")
        self.outputs[0].sv_set(wrap_output_data(self.obj))

def register():
    bpy.utils.register_class(SvGetPropNode)


def unregister():
    bpy.utils.unregister_class(SvGetPropNode)