substrate_interface/substrateinterface/storage.py

# Python Substrate Interface Library
#
# Copyright 2018-2023 Stichting Polkascan (Polkascan Foundation).
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import binascii
from typing import Any, Optional

from substrateinterface.exceptions import StorageFunctionNotFound

from scalecodec import ScaleBytes, GenericMetadataVersioned, ss58_decode
from scalecodec.base import ScaleDecoder, RuntimeConfigurationObject, ScaleType
from .utils.hasher import blake2_256, two_x64_concat, xxh128, blake2_128, blake2_128_concat, identity


class StorageKey:
    """
    A StorageKey instance is a representation of a single state entry.

    Substrate uses a simple key-value data store implemented as a database-backed, modified Merkle tree.
    All of Substrate's higher-level storage abstractions are built on top of this simple key-value store.
    """

    def __init__(
            self, pallet: str, storage_function: str, params: list,
            data: bytes, value_scale_type: str, metadata: GenericMetadataVersioned,
            runtime_config: RuntimeConfigurationObject
    ):
        self.pallet = pallet
        self.storage_function = storage_function
        self.params = params
        self.params_encoded = []
        self.data = data
        self.metadata = metadata
        self.runtime_config = runtime_config
        self.value_scale_type = value_scale_type
        self.metadata_storage_function = None

    @classmethod
    def create_from_data(cls, data: bytes, runtime_config: RuntimeConfigurationObject,
                         metadata: GenericMetadataVersioned, value_scale_type: str = None, pallet: str = None,
                         storage_function: str = None) -> 'StorageKey':
        """
        Create a StorageKey instance providing raw storage key bytes

        Parameters
        ----------
        data: bytes representation of the storage key
        runtime_config: RuntimeConfigurationObject
        metadata: GenericMetadataVersioned
        value_scale_type: type string of to decode result data
        pallet: name of pallet
        storage_function: name of storage function

        Returns
        -------
        StorageKey
        """
        if not value_scale_type and pallet and storage_function:
            metadata_pallet = metadata.get_metadata_pallet(pallet)

            if not metadata_pallet:
                raise StorageFunctionNotFound(f'Pallet "{pallet}" not found')

            storage_item = metadata_pallet.get_storage_function(storage_function)

            if not storage_item:
                raise StorageFunctionNotFound(f'Storage function "{pallet}.{storage_function}" not found')

            # Process specific type of storage function
            value_scale_type = storage_item.get_value_type_string()

        return cls(
            pallet=None, storage_function=None, params=None,
            data=data, metadata=metadata,
            value_scale_type=value_scale_type, runtime_config=runtime_config
        )

    @classmethod
    def create_from_storage_function(cls, pallet: str, storage_function: str, params: list,
                                     runtime_config: RuntimeConfigurationObject,
                                     metadata: GenericMetadataVersioned) -> 'StorageKey':
        """
        Create a StorageKey instance providing storage function details

        Parameters
        ----------
        pallet: name of pallet
        storage_function: name of storage function
        params: Optional list of parameters in case of a Mapped storage function
        runtime_config: RuntimeConfigurationObject
        metadata: GenericMetadataVersioned

        Returns
        -------
        StorageKey
        """
        storage_key_obj = cls(
            pallet=pallet, storage_function=storage_function, params=params,
            data=None, runtime_config=runtime_config, metadata=metadata, value_scale_type=None
        )

        storage_key_obj.generate()

        return storage_key_obj

    def convert_storage_parameter(self, scale_type: str, value: Any):

        if type(value) is bytes:
            value = f'0x{value.hex()}'

        if scale_type == 'AccountId':
            if value[0:2] != '0x':
                return '0x{}'.format(ss58_decode(value, self.runtime_config.ss58_format))

        return value

    def to_hex(self) -> str:
        """
        Returns a Hex-string representation of current StorageKey data

        Returns
        -------
        str
            Hex string
        """
        if self.data:
            return f'0x{self.data.hex()}'

    def generate(self) -> bytes:
        """
        Generate a storage key for current specified pallet/function/params

        Returns
        -------
        bytes
        """

        # Search storage call in metadata
        metadata_pallet = self.metadata.get_metadata_pallet(self.pallet)

        if not metadata_pallet:
            raise StorageFunctionNotFound(f'Pallet "{self.pallet}" not found')

        self.metadata_storage_function = metadata_pallet.get_storage_function(self.storage_function)

        if not self.metadata_storage_function:
            raise StorageFunctionNotFound(f'Storage function "{self.pallet}.{self.storage_function}" not found')

        # Process specific type of storage function
        self.value_scale_type = self.metadata_storage_function.get_value_type_string()
        param_types = self.metadata_storage_function.get_params_type_string()

        hashers = self.metadata_storage_function.get_param_hashers()

        storage_hash = xxh128(metadata_pallet.value['storage']['prefix'].encode()) + xxh128(self.storage_function.encode())

        # Encode parameters
        self.params_encoded = []
        if self.params:
            for idx, param in enumerate(self.params):
                if type(param) is ScaleBytes:
                    # Already encoded
                    self.params_encoded.append(param)
                else:
                    param = self.convert_storage_parameter(param_types[idx], param)
                    param_obj = self.runtime_config.create_scale_object(type_string=param_types[idx])
                    self.params_encoded.append(param_obj.encode(param))

            for idx, param in enumerate(self.params_encoded):
                # Get hasher assiociated with param
                try:
                    param_hasher = hashers[idx]
                except IndexError:
                    raise ValueError(f'No hasher found for param #{idx + 1}')

                params_key = bytes()

                # Convert param to bytes
                if type(param) is str:
                    params_key += binascii.unhexlify(param)
                elif type(param) is ScaleBytes:
                    params_key += param.data
                elif isinstance(param, ScaleDecoder):
                    params_key += param.data.data

                if not param_hasher:
                    param_hasher = 'Twox128'

                if param_hasher == 'Blake2_256':
                    storage_hash += blake2_256(params_key)

                elif param_hasher == 'Blake2_128':
                    storage_hash += blake2_128(params_key)

                elif param_hasher == 'Blake2_128Concat':
                    storage_hash += blake2_128_concat(params_key)

                elif param_hasher == 'Twox128':
                    storage_hash += xxh128(params_key)

                elif param_hasher == 'Twox64Concat':
                    storage_hash += two_x64_concat(params_key)

                elif param_hasher == 'Identity':
                    storage_hash += identity(params_key)

                else:
                    raise ValueError('Unknown storage hasher "{}"'.format(param_hasher))

        self.data = storage_hash

        return self.data

    def decode_scale_value(self, data: Optional[ScaleBytes] = None) -> ScaleType:
        """

        Parameters
        ----------
        data

        Returns
        -------

        """

        result_found = False

        if data is not None:
            change_scale_type = self.value_scale_type
            result_found = True
        elif self.metadata_storage_function.value['modifier'] == 'Default':
            # Fallback to default value of storage function if no result
            change_scale_type = self.value_scale_type
            data = ScaleBytes(self.metadata_storage_function.value_object['default'].value_object)
        else:
            # No result is interpreted as an Option<...> result
            change_scale_type = f'Option<{self.value_scale_type}>'
            data = ScaleBytes(self.metadata_storage_function.value_object['default'].value_object)

        # Decode SCALE result data
        updated_obj = self.runtime_config.create_scale_object(
            type_string=change_scale_type,
            data=data,
            metadata=self.metadata
        )
        updated_obj.decode()
        updated_obj.meta_info = {'result_found': result_found}

        return updated_obj

    def __repr__(self):
        if self.pallet and self.storage_function:
            return f'<StorageKey(pallet={self.pallet}, storage_function={self.storage_function}, params={self.params})>'
        elif self.data:
            return f'<StorageKey(data=0x{self.data.hex()})>'
        else:
            return repr(self)