Add memory db in client

plasma_cash/client/db/db_interface.py

@@ -0,0 +1,12 @@
+import abc
+
+
+class DbInterface(abc.ABC):
+
+    @abc.abstractmethod
+    def get_history(self, uid):
+        return NotImplemented
+
+    @abc.abstractmethod
+    def save_history(self, uid, history):
+        return NotImplemented

plasma_cash/client/db/memory_db.py

@@ -0,0 +1,13 @@
+from .db_interface import DbInterface
+
+
+class MemoryDb(DbInterface):
+
+    def __init__(self):
+        self.uid = {}
+
+    def get_history(self, uid):
+        return self.uid.get(uid)
+
+    def save_history(self, uid, history):
+        self.uid[uid] = history

plasma_cash/client/exceptions.py

@@ -1,2 +1,6 @@
 class RequestFailedException(Exception):
     """request failed without success http status"""
+
+
+class TxHistoryNotFoundException(Exception):
+    """tx history is not found for specific block number"""

plasma_cash/client/history.py

@@ -0,0 +1,36 @@
+import rlp
+from rlp.sedes import big_endian_int, binary, CountableList
+
+from .exceptions import TxHistoryNotFoundException
+
+
+class History(rlp.Serializable):
+    EMPTY_TX = b'\x00' * 32
+
+    fields = [
+        ('latest_tx_blk_num', big_endian_int),
+        ('tx_history', CountableList(binary)),
+        ('proofs', CountableList(binary)),
+        ('blk_num', CountableList(big_endian_int))
+    ]
+
+    def __init__(self, deposit_tx_blk_num, tx, proof):
+        self.latest_tx_blk_num = deposit_tx_blk_num
+        self.tx_history = [tx]
+        self.proofs = [proof]
+        self.blk_num = [deposit_tx_blk_num]
+
+    def update_tx_history(self, blk_num, tx, proof):
+        if blk_num not in self.blk_num:
+            if tx != self.EMPTY_TX:
+                self.latest_tx_blk_num = max(self.latest_tx_blk_num, blk_num)
+            self.tx_history.append(tx)
+            self.proofs.append(proof)
+            self.blk_num.append(blk_num)
+
+    def get_data_by_block(self, blk_num):
+        try:
+            idx = self.blk_num.index(blk_num)
+        except ValueError:
+            raise TxHistoryNotFoundException('tx history not found')
+        return self.tx_history[idx], self.proofs[idx]

unit_tests/client/db/test_memory_db.py

@@ -0,0 +1,19 @@
+import pytest
+
+from plasma_cash.client.db.memory_db import MemoryDb
+
+
+class TestMemoryDb(object):
+    @pytest.fixture(scope='function')
+    def db(self):
+        return MemoryDb()
+
+    def test_save_and_get_history(self, db):
+        DUMMY_HISTORY = 'dummy history'
+        DUMMY_UID = 1
+        db.save_history(DUMMY_UID, DUMMY_HISTORY)
+        assert db.get_history(DUMMY_UID) == DUMMY_HISTORY
+
+    def test_history_not_found(self, db):
+        DUMMY_UID = 1
+        assert db.get_history(DUMMY_UID) is None

unit_tests/client/test_history.py

@@ -0,0 +1,69 @@
+import pytest
+
+from plasma_cash.client.exceptions import TxHistoryNotFoundException
+from plasma_cash.client.history import History
+
+
+class TestHistory(object):
+    DUMMY_DEPOSIT_BLK_NUM = 1
+    DUMMY_TX1 = 'dummy tx1'
+    DUMMY_PROOF1 = 'dummy proof1'
+
+    @pytest.fixture(scope='function')
+    def history(self):
+        return History(self.DUMMY_DEPOSIT_BLK_NUM, self.DUMMY_TX1, self.DUMMY_PROOF1)
+
+    def test_constructor(self):
+        history = History(self.DUMMY_DEPOSIT_BLK_NUM, self.DUMMY_TX1, self.DUMMY_PROOF1)
+        assert history.latest_tx_blk_num == self.DUMMY_DEPOSIT_BLK_NUM
+        assert history.tx_history == [self.DUMMY_TX1]
+        assert history.proofs == [self.DUMMY_PROOF1]
+        assert history.blk_num == [self.DUMMY_DEPOSIT_BLK_NUM]
+
+    def test_update_history(self, history):
+        DUMMY_BLK_NUM = 2
+        DUMMY_TX2 = 'dummy tx2'
+        DUMMY_PROOF2 = 'dummy proof2'
+        history.update_tx_history(DUMMY_BLK_NUM, DUMMY_TX2, DUMMY_PROOF2)
+        assert history.latest_tx_blk_num == 2
+        assert history.tx_history == [self.DUMMY_TX1, DUMMY_TX2]
+        assert history.proofs == [self.DUMMY_PROOF1, DUMMY_PROOF2]
+        assert history.blk_num == [1, 2]
+
+    def test_update_empty_history(self, history):
+        DUMMY_BLK_NUM = 2
+        EMPTY_TX = b'\x00' * 32
+        NON_INCLUSIVE_PROOF = 'non inclusion proof'
+        history.update_tx_history(DUMMY_BLK_NUM, EMPTY_TX, NON_INCLUSIVE_PROOF)
+        assert history.latest_tx_blk_num == 1
+        assert history.tx_history == [self.DUMMY_TX1, EMPTY_TX]
+        assert history.proofs == [self.DUMMY_PROOF1, NON_INCLUSIVE_PROOF]
+        assert history.blk_num == [1, 2]
+
+    def test_update_history_with_wrong_order(self, history):
+        DUMMY_BLK_NUM = 3
+        DUMMY_TX3 = 'dummy tx3'
+        DUMMY_PROOF3 = 'dummy proof3'
+        history.update_tx_history(DUMMY_BLK_NUM, DUMMY_TX3, DUMMY_PROOF3)
+        assert history.tx_history == [self.DUMMY_TX1, DUMMY_TX3]
+        assert history.proofs == [self.DUMMY_PROOF1, DUMMY_PROOF3]
+        assert history.blk_num == [1, 3]
+
+        DUMMY_BLK_NUM = 2
+        DUMMY_TX2 = 'dummy tx2'
+        DUMMY_PROOF2 = 'dummy proof2'
+        history.update_tx_history(DUMMY_BLK_NUM, DUMMY_TX2, DUMMY_PROOF2)
+        assert history.tx_history == [self.DUMMY_TX1, DUMMY_TX3, DUMMY_TX2]
+        assert history.proofs == [self.DUMMY_PROOF1, DUMMY_PROOF3, DUMMY_PROOF2]
+        assert history.blk_num == [1, 3, 2]
+
+    def test_get_data_by_block(self, history):
+        DUMMY_BLK_NUM = 1
+        tx, proof = history.get_data_by_block(DUMMY_BLK_NUM)
+        assert tx == history.tx_history[0]
+        assert proof == history.proofs[0]
+
+    def test_get_data_by_block_failed(self, history):
+        DUMMY_BLK_NUM = 2
+        with pytest.raises(TxHistoryNotFoundException):
+            history.get_data_by_block(DUMMY_BLK_NUM)