Add graphene common, instance, and wallet

graphenecommon/exceptions.py

@@ -0,0 +1,60 @@
+__all__ = [
+    "InvalidWifError",
+    "KeyAlreadyInStoreException",
+    "KeyNotFound",
+    "NoWalletException",
+    "OfflineHasNoRPCException",
+    "WalletExists",
+    "WalletLocked",
+]
+
+
+class WalletExists(Exception):
+    """ A wallet has already been created and requires a password to be
+        unlocked by means of :func:`bitshares.wallet.unlock`.
+    """
+
+    pass
+
+
+class WalletLocked(Exception):
+    """ Wallet is locked
+    """
+
+    pass
+
+
+class OfflineHasNoRPCException(Exception):
+    """ When in offline mode, we don't have RPC
+    """
+
+    pass
+
+
+class NoWalletException(Exception):
+    """ No Wallet could be found, please use :func:`bitshares.wallet.create` to
+        create a new wallet
+    """
+
+    pass
+
+
+class KeyNotFound(Exception):
+    """ Key not found
+    """
+
+    pass
+
+
+class KeyAlreadyInStoreException(Exception):
+    """ The key is already stored in the store
+    """
+
+    pass
+
+
+class InvalidWifError(Exception):
+    """ The provided private Key has an invalid format
+    """
+
+    pass

graphenecommon/instance.py

@@ -0,0 +1,67 @@
+class SharedInstance:
+    """ This class merely offers a singelton for the Blockchain Instance
+    """
+
+    instance = None
+    config = {}
+
+
+class BlockchainInstance:
+    """ This is a class that allows compatibility with previous
+        naming conventions. It will extract 'blockchain_instance'
+        from the key word arguments and ensure that self.blockchain
+        contains an instance of the main chain instance
+    """
+
+    def get_instance_class(self):
+        """ Should return the Chain instance class, e.g. `bitshares.BitShares`
+        """
+        raise NotImplementedError
+
+    def clear_cache(self):
+        raise NotImplementedError
+
+    def __init__(self, *args, **kwargs):
+        if "blockchain_instance" in kwargs and kwargs["blockchain_instance"]:
+            SharedInstance.instance = kwargs["blockchain_instance"]
+
+    @property
+    def blockchain(self):
+        return self.shared_blockchain_instance()
+
+    @property
+    def chain(self):
+        """ Short form for blockchain (for the lazy)
+        """
+        return self.blockchain
+
+    def shared_blockchain_instance(self):
+        """ This method will initialize ``SharedInstance.instance`` and return it.
+            The purpose of this method is to have offer single default
+            instance that can be reused by multiple classes.
+        """
+        if not SharedInstance.instance:
+            klass = self.get_instance_class()
+            SharedInstance.instance = klass(**SharedInstance.config)
+        return SharedInstance.instance
+
+    @staticmethod
+    def set_shared_blockchain_instance(instance):
+        """ This method allows us to override default instance for all
+            users of ``SharedInstance.instance``.
+
+            :param chaininstance instance: Chain instance
+        """
+        SharedInstance.instance = instance
+
+    def set_shared_config(self, config):
+        """ This allows to set a config that will be used when calling
+            ``shared_blockchain_instance`` and allows to define the configuration
+            without requiring to actually create an instance
+        """
+        assert isinstance(config, dict)
+        SharedInstance.config.update(config)
+        # if one is already set, delete
+        if SharedInstance.instance:
+            self.shared_blockchain_instance().clear_cache()
+            SharedInstance.instance = None