refactor: remove SimpleMemoryStorage and refactor DAA (#1026)

hathor/daa.py

@@ -21,19 +21,17 @@
 
 from enum import IntFlag
 from math import log
-from typing import TYPE_CHECKING, ClassVar, Optional
+from typing import TYPE_CHECKING, Callable, ClassVar, Optional
 
 from structlog import get_logger
 
 from hathor.conf.settings import HathorSettings
 from hathor.profiler import get_cpu_profiler
 from hathor.types import VertexId
-from hathor.util import iwindows, not_none
+from hathor.util import iwindows
 
 if TYPE_CHECKING:
     from hathor.transaction import Block, Transaction
-    from hathor.transaction.storage.simple_memory_storage import SimpleMemoryStorage
-    from hathor.transaction.storage.vertex_storage_protocol import VertexStorageProtocol
 
 logger = get_logger()
 cpu = get_cpu_profiler()
@@ -60,35 +58,43 @@ def __init__(self, *, settings: HathorSettings, test_mode: TestMode = TestMode.D
         DifficultyAdjustmentAlgorithm.singleton = self
 
     @cpu.profiler(key=lambda _, block: 'calculate_block_difficulty!{}'.format(block.hash.hex()))
-    def calculate_block_difficulty(self, block: 'Block', memory_storage: 'SimpleMemoryStorage') -> float:
+    def calculate_block_difficulty(self, block: 'Block', parent_block_getter: Callable[['Block'], 'Block']) -> float:
         """ Calculate block weight according to the ascendants of `block`, using calculate_next_weight."""
         if self.TEST_MODE & TestMode.TEST_BLOCK_WEIGHT:
             return 1.0
 
         if block.is_genesis:
             return self.MIN_BLOCK_WEIGHT
 
-        parent_block = memory_storage.get_parent_block(block)
-
-        return self.calculate_next_weight(parent_block, block.timestamp, memory_storage)
+        parent_block = parent_block_getter(block)
+        return self.calculate_next_weight(parent_block, block.timestamp, parent_block_getter)
 
     def _calculate_N(self, parent_block: 'Block') -> int:
         """Calculate the N value for the `calculate_next_weight` algorithm."""
         return min(2 * self._settings.BLOCK_DIFFICULTY_N_BLOCKS, parent_block.get_height() - 1)
 
-    def get_block_dependencies(self, block: 'Block') -> list[VertexId]:
+    def get_block_dependencies(
+        self,
+        block: 'Block',
+        parent_block_getter: Callable[['Block'], 'Block'],
+    ) -> list[VertexId]:
         """Return the ids of the required blocks to call `calculate_block_difficulty` for the provided block."""
-        parent_block = block.get_block_parent()
+        parent_block = parent_block_getter(block)
         N = self._calculate_N(parent_block)
-        ids: list[VertexId] = [not_none(parent_block.hash)]
+        ids: list[VertexId] = [parent_block.hash]
 
         while len(ids) <= N + 1:
-            parent_block = parent_block.get_block_parent()
-            ids.append(not_none(parent_block.hash))
+            parent_block = parent_block_getter(parent_block)
+            ids.append(parent_block.hash)
 
         return ids
 
-    def calculate_next_weight(self, parent_block: 'Block', timestamp: int, storage: 'VertexStorageProtocol') -> float:
+    def calculate_next_weight(
+        self,
+        parent_block: 'Block',
+        timestamp: int,
+        parent_block_getter: Callable[['Block'], 'Block'],
+    ) -> float:
         """ Calculate the next block weight, aka DAA/difficulty adjustment algorithm.
 
         The algorithm used is described in [RFC 22](https://gitlab.com/HathorNetwork/rfcs/merge_requests/22).
@@ -111,8 +117,7 @@ def calculate_next_weight(self, parent_block: 'Block', timestamp: int, storage:
         blocks: list['Block'] = []
         while len(blocks) < N + 1:
             blocks.append(root)
-            root = storage.get_parent_block(root)
-            assert root is not None
+            root = parent_block_getter(root)
 
         # TODO: revise if this assertion can be safely removed
         assert blocks == sorted(blocks, key=lambda tx: -tx.timestamp)

hathor/manager.py

@@ -816,7 +816,10 @@ def _make_block_template(self, parent_block: Block, parent_txs: 'ParentTxs', cur
             parent_block_metadata.score,
             2 * self._settings.WEIGHT_TOL
         )
-        weight = max(self.daa.calculate_next_weight(parent_block, timestamp, self.tx_storage), min_significant_weight)
+        weight = max(
+            self.daa.calculate_next_weight(parent_block, timestamp, self.tx_storage.get_parent_block),
+            min_significant_weight
+        )
         height = parent_block.get_height() + 1
         parents = [parent_block.hash] + parent_txs.must_include
         parents_any = parent_txs.can_include

hathor/simulator/simulator.py

@@ -253,7 +253,7 @@ def _build_vertex_verifiers(
     """
     return VertexVerifiers.create(
         settings=settings,
-        vertex_verifier=SimulatorVertexVerifier(settings=settings, daa=daa),
+        vertex_verifier=SimulatorVertexVerifier(settings=settings),
         daa=daa,
         feature_service=feature_service,
     )

hathor/stratum/stratum.py

@@ -526,7 +526,7 @@ def handle_submit(self, params: dict, msgid: Optional[str]) -> None:
 
         self.log.debug('share received', block=tx, block_base=block_base.hex(), block_base_hash=block_base_hash.hex())
 
-        verifier = VertexVerifier(settings=self._settings, daa=self.manager.daa)
+        verifier = VertexVerifier(settings=self._settings)
 
         try:
             verifier.verify_pow(tx, override_weight=job.weight)

hathor/verification/block_verifier.py

@@ -25,8 +25,6 @@
     TransactionDataError,
     WeightError,
 )
-from hathor.transaction.storage.simple_memory_storage import SimpleMemoryStorage
-from hathor.util import not_none
 
 
 class BlockVerifier:
@@ -53,11 +51,8 @@ def verify_height(self, block: Block) -> None:
 
     def verify_weight(self, block: Block) -> None:
         """Validate minimum block difficulty."""
-        memory_storage = SimpleMemoryStorage()
-        dependencies = self._daa.get_block_dependencies(block)
-        memory_storage.add_vertices_from_storage(not_none(block.storage), dependencies)
-
-        min_block_weight = self._daa.calculate_block_difficulty(block, memory_storage)
+        assert block.storage is not None
+        min_block_weight = self._daa.calculate_block_difficulty(block, block.storage.get_parent_block)
         if block.weight < min_block_weight - self._settings.WEIGHT_TOL:
             raise WeightError(f'Invalid new block {block.hash_hex}: weight ({block.weight}) is '
                               f'smaller than the minimum weight ({min_block_weight})')

hathor/verification/vertex_verifier.py

@@ -15,7 +15,6 @@
 from typing import Optional
 
 from hathor.conf.settings import HathorSettings
-from hathor.daa import DifficultyAdjustmentAlgorithm
 from hathor.transaction import BaseTransaction
 from hathor.transaction.exceptions import (
     DuplicatedParents,
@@ -40,11 +39,10 @@
 
 
 class VertexVerifier:
-    __slots__ = ('_settings', '_daa')
+    __slots__ = ('_settings',)
 
-    def __init__(self, *, settings: HathorSettings, daa: DifficultyAdjustmentAlgorithm):
+    def __init__(self, *, settings: HathorSettings) -> None:
         self._settings = settings
-        self._daa = daa
 
     def verify_parents(self, vertex: BaseTransaction) -> None:
         """All parents must exist and their timestamps must be smaller than ours.
@@ -158,7 +156,7 @@ def verify_outputs(self, vertex: BaseTransaction) -> None:
                 ))
 
     def verify_number_of_outputs(self, vertex: BaseTransaction) -> None:
-        """Verify number of outputs does not exceeds the limit"""
+        """Verify number of outputs does not exceed the limit"""
         if len(vertex.outputs) > self._settings.MAX_NUM_OUTPUTS:
             raise TooManyOutputs('Maximum number of outputs exceeded')
 

hathor/verification/vertex_verifiers.py

@@ -44,7 +44,7 @@ def create_defaults(
         Create a VertexVerifiers instance using the default verifier for each vertex type,
         from all required dependencies.
         """
-        vertex_verifier = VertexVerifier(settings=settings, daa=daa)
+        vertex_verifier = VertexVerifier(settings=settings)
 
         return cls.create(
             settings=settings,

tests/simulation/test_simulator.py

@@ -14,7 +14,7 @@ def test_verify_pow(self) -> None:
         # just get one of the genesis, we don't really need to create any transaction
         tx = next(iter(manager1.tx_storage.get_all_genesis()))
         # optional argument must be valid, it just has to not raise any exception, there's no assert for that
-        VertexVerifier(settings=self._settings, daa=manager1.daa).verify_pow(tx, override_weight=0.)
+        VertexVerifier(settings=self._settings).verify_pow(tx, override_weight=0.)
 
     def test_one_node(self) -> None:
         manager1 = self.create_peer()

tests/tx/test_genesis.py

@@ -37,7 +37,7 @@ def setUp(self):
         self.storage = TransactionMemoryStorage()
 
     def test_pow(self):
-        verifier = VertexVerifier(settings=self._settings, daa=self._daa)
+        verifier = VertexVerifier(settings=self._settings)
         genesis = self.storage.get_all_genesis()
         for g in genesis:
             self.assertEqual(g.calculate_hash(), g.hash)