Big change to operation!
This commit is contained in:
wqy
320
api/operation.py
320
api/operation.py
@@ -1,111 +1,130 @@
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from psycopg.rows import dict_row, Row
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from .connection import g_conn_dict as conn
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from .utility import *
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from .change_set import *
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def _get_current_transaction(name: str) -> Row | None:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select * from transaction_operation")
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return cur.fetchone()
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def _get_current_transaction_id(name: str) -> int:
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row = _get_current_transaction(name)
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return int(row['id'])
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API_ADD = 'add'
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API_DELETE = 'delete'
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API_UPDATE = 'update'
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def _remove_transaction(name: str) -> None:
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with conn[name].cursor() as cur:
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cur.execute(f"delete from transaction_operation")
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def _remove_operation(name: str, id: int) -> None:
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with conn[name].cursor(row_factory=dict_row) as cur:
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# can not be >= to cascade delete since there is a tree !
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cur.execute(f"delete from transaction_operation where id = {id}") # this should not happen
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cur.execute(f"delete from snapshot_operation where id = {id}") # this may happen
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cur.execute(f"delete from operation where id = {id}")
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row = read(name, f'select * from operation where parent = {id}')
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if row != None:
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raise Exception('Disallow to remove parent operation !')
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sql += f'delete from snapshot_operation where id = {id};'
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sql += f'delete from operation where id = {id}'
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write(name, sql)
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def _get_parents(name: str, id: int) -> list[int]:
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ids = [id]
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with conn[name].cursor(row_factory=dict_row) as cur:
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while ids[-1] != 0:
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cur.execute(f"select parent from operation where id = {ids[-1]}")
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ids.append(int(cur.fetchone()['parent']))
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while ids[-1] != 0:
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row = read(name, f'select parent from operation where id = {ids[-1]}')
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ids.append(int(row['parent']))
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return ids
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def get_current_operation(name: str) -> int:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select id from current_operation")
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return int(cur.fetchone()['id'])
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row = read(name, f'select id from current_operation')
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return int(row['id'])
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def _update_current_operation(name: str, old_id: int, id: int) -> None:
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with conn[name].cursor() as cur:
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cur.execute(f"update current_operation set id = {id} where id = {old_id}")
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return write(name, f'update current_operation set id = {id} where id = {old_id}')
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def _add_redo_undo(name: str, redo: str, undo: str) -> int:
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with conn[name].cursor(row_factory=dict_row) as cur:
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parent = get_current_operation(name)
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cur.execute(f"insert into operation (id, redo, undo, parent) values (default, '{redo}', '{undo}', {parent})")
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cur.execute("select max(id) from operation")
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return int(cur.fetchone()['max'])
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# execute curr undo
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def _query_undo(name: str, id: str) -> dict[str, str]:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select undo, parent from operation where id = {id}")
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return cur.fetchone()
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def _add_redo_undo(name: str, redo: str, undo: str, api_id: str, api_op: str, api_object_type: str, api_object_id: str, api_object_properties: list[str]) -> int:
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parent = get_current_operation(name)
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ps = []
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for p in api_object_properties:
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ps.append(f'"{p}"')
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if len(ps) > 0:
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ps = ','.join(ps)
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ps = '{' + ps + '}'
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sql = f"insert into operation (id, redo, undo, parent, api_id, api_op, api_object_type, api_object_id, api_object_properties) values (default, '{redo}', '{undo}', {parent}, '{api_id}', '{api_op}', '{api_object_type}', '{api_object_id}', '{ps}')"
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else:
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sql = f"insert into operation (id, redo, undo, parent, api_id, api_op, api_object_type, api_object_id) values (default, '{redo}', '{undo}', {parent}, '{api_id}', '{api_op}', '{api_object_type}', '{api_object_id}')"
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write(name, sql)
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return int(read(name, 'select max(id) from operation')['max'])
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def _query_operation(name: str, id: str) -> dict[str, str]:
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return read(name, f'select * from operation where id = {id}')
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# execute next redo
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def _query_redo_child(name: str, id: str) -> str:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select redo_child from operation where id = {id}")
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return cur.fetchone()['redo_child']
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row = read(name, f'select redo_child from operation where id = {id}')
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return row['redo_child']
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def _query_redo(name: str, id: str) -> dict[str, str]:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select redo from operation where id = {id}")
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return cur.fetchone()['redo']
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def _set_redo_child(name: str, id: int, child: int | str) -> None:
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with conn[name].cursor() as cur:
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cur.execute(f"update operation set redo_child = {child} where id = {id}")
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return write(name, f'update operation set redo_child = {child} where id = {id}')
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def _execute(name: str, sql: str) -> None:
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with conn[name].cursor() as cur:
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sql = sql.replace("\"", "\'")
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cur.execute(sql)
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def add_operation(name: str, redo: str, undo: str) -> None:
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curr = _add_redo_undo(name, redo, undo)
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def add_operation(name: str, redo: str, undo: str, api_id: str, api_op: str, api_object_type: str, api_object_id: str, api_object_properties: list[str] = []) -> None:
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curr = _add_redo_undo(name, redo, undo, api_id, api_op, api_object_type, api_object_id, api_object_properties)
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old = get_current_operation(name)
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_update_current_operation(name, old, curr)
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def execute_undo(name: str, discard: bool = False) -> None:
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def _reverser_op(op: str) -> str:
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if op == API_ADD:
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return API_DELETE
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elif op == API_DELETE:
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return API_ADD
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else:
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return op
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def _get_change_set(row: dict[str, str], undo: bool) -> ChangeSet:
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op = row['api_op']
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if undo:
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op = _reverser_op(op)
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type = row['api_object_type']
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id = row['api_object_id']
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change = ChangeSet()
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if op == API_ADD:
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change.add(type, id)
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elif op == API_DELETE:
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change.delete(type, id)
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elif op == API_UPDATE:
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ps = row['api_object_properties'].removeprefix('{').removesuffix('}').split(',')
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change.update(type, id, ps)
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return change
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def execute_undo(name: str, discard: bool) -> ChangeSet:
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curr = get_current_operation(name)
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# transaction control
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if have_transaction(name):
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tran = _get_current_transaction(name)
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if tran != None and int(tran['id']) >= 0:
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if bool(tran['strict']): # strict mode disallow undo
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print("Do not allow to undo in strict transaction mode!")
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return
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elif int(tran['id']) >= curr: # normal mode disallow undo start point, and there is foreign key constraint
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print("Do not allow to undo transaction start point!")
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return
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row = _query_undo(name, curr)
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row = _query_operation(name, curr)
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undo = row['undo']
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if undo == '':
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print("nothing to undo!")
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return
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parent = int(row['parent'])
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_set_redo_child(name, parent, 'NULL' if discard else curr)
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change = _get_change_set(row, True)
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_execute(name, undo)
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parent = int(row['parent'])
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_set_redo_child(name, parent, 'null' if discard else curr)
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write(name, undo)
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_update_current_operation(name, curr, parent)
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if discard:
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_remove_operation(name, curr)
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def execute_redo(name: str) -> None:
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return change
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def execute_redo(name: str) -> ChangeSet:
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curr = get_current_operation(name)
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redoChild = _query_redo_child(name, curr)
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if redoChild == None:
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@@ -113,108 +132,127 @@ def execute_redo(name: str) -> None:
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return
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child = int(redoChild)
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redo = _query_redo(name, child)
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row = _query_operation(name, child)
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redo = row['redo']
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_execute(name, redo)
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change = _get_change_set(row, False)
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write(name, redo)
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_update_current_operation(name, curr, child)
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# snapshot support to checkout between different version of database
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# snapshot is persistent
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# since redo always remember the recently undo path
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return change
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def _get_operation_by_tag(name: str, tag: str) -> int | None:
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row = read(name, f"select id from snapshot_operation where tag = '{tag}'")
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return int(row['id']) if row != None else None
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def have_snapshot(name: str, tag: str) -> bool:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select id from snapshot_operation where tag = '{tag}'")
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return cur.rowcount > 0
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return _get_operation_by_tag(name, tag) != None
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def take_snapshot(name: str, tag: str) -> None:
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def take_snapshot(name: str, tag: str) -> int | None:
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if tag == None or tag == '':
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print('Non empty tag is expected!')
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return
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return None
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curr = get_current_operation(name)
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write(name, f"insert into snapshot_operation (id, tag) values ({curr}, '{tag}')")
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return curr
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with conn[name].cursor() as cur:
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cur.execute(f"insert into snapshot_operation (id, tag) values ({curr}, '{tag}')")
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def pick_snapshot(name: str, tag: str) -> None:
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def pick_snapshot(name: str, tag: str, discard: bool) -> ChangeSet:
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if tag == None or tag == '':
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print('Non empty tag is expected!')
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return
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return ChangeSet()
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if not have_snapshot(name, tag):
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target = _get_operation_by_tag(name, tag)
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if target == None:
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print('No such snapshot!')
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return
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return ChangeSet()
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curr = get_current_operation(name)
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curr_parents = _get_parents(name, curr)
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target_parents = _get_parents(name, target)
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select id from snapshot_operation where tag = '{tag}'")
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target = int(cur.fetchone()['id'])
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if target in curr_parents: # target -> curr
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for i in range(curr_parents.index(target)):
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execute_undo(name)
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else:
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target_parents = _get_parents(name, target)
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if curr in target_parents: # curr -> target
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for i in range(target_parents.index(curr)):
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execute_redo(name)
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else:
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ancestor_index = -1
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while curr_parents[ancestor_index] == target_parents[ancestor_index]:
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ancestor_index -= 1
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change = ChangeSet()
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# ancestor -> curr
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ancestor = curr_parents[ancestor_index + 1] # ancestor_index + 1 is common parent
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for i in range(curr_parents.index(ancestor)):
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execute_undo(name)
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# ancestor -> redo, need assign redo_child
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while target_parents[ancestor_index] != target:
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cur.execute(f"update operation set redo_child = '{target_parents[ancestor_index]}' where id = '{target_parents[ancestor_index + 1]}'")
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execute_redo(name)
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ancestor_index -= 1
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cur.execute(f"update operation set redo_child = '{target}' where id = '{target_parents[1]}'")
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execute_redo(name)
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if target in curr_parents:
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for _ in range(curr_parents.index(target)):
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change.append(execute_undo(name, discard))
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# transaction is volatile, commit/abort will destroy transaction.
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# can not redo an aborted transaction.
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# but can undo a committed transaction... inconsistent...
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# it may remove snapshot if it is in aborted transaction
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elif curr in target_parents:
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target_parents.reverse()
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curr_index = target_parents.index(curr)
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for i in range(curr_index, len(target_parents) - 1):
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write(name, f"update operation set redo_child = '{target_parents[i + 1]}' where id = '{target_parents[i]}'")
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change.append(execute_redo(name))
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def have_transaction(name: str) -> bool:
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with conn[name].cursor(row_factory=dict_row) as cur:
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cur.execute(f"select * from transaction_operation")
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return cur.rowcount > 0
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else:
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ancestor_index = -1
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while curr_parents[ancestor_index] == target_parents[ancestor_index]:
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ancestor_index -= 1
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ancestor = curr_parents[ancestor_index + 1]
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def start_transaction(name: str, strict: bool = False) -> None:
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if have_transaction(name):
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print("Only support single transaction now, please commit/abort current transaction!")
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return
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for _ in range(curr_parents.index(ancestor)):
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change.append(execute_undo(name, discard))
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curr = get_current_operation(name)
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target_parents.reverse()
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curr_index = target_parents.index(ancestor)
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for i in range(curr_index, len(target_parents) - 1):
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write(name, f"update operation set redo_child = '{target_parents[i + 1]}' where id = '{target_parents[i]}'")
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change.append(execute_redo(name))
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with conn[name].cursor() as cur:
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cur.execute(f"insert into transaction_operation (id, strict) values ({curr}, {strict});")
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return change.compress()
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def commit_transaction(name: str) -> None:
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if not have_transaction(name):
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print("No active transaction!")
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return
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_remove_transaction(name)
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def get_change_set(name: str, operation: int, undo: bool) -> ChangeSet:
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row = read(name, f'select api_id, api_op, api_object_type, api_object_id, api_object_properties from operation where id = {operation}')
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return _get_change_set(row, undo)
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def abort_transaction(name: str) -> None:
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if not have_transaction(name):
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print("No active transaction!")
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return
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tran = _get_current_transaction_id(name)
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def get_current_change_set(name: str) -> ChangeSet:
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return get_change_set(name, get_current_operation(name), False)
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curr = get_current_operation(name)
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curr_parents = _get_parents(name, curr)
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for i in range(curr_parents.index(tran)):
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execute_undo(name, True)
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_remove_transaction(name)
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def sync_with_server(name: str, operation: int) -> ChangeSet:
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fr = operation
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to = get_current_operation(name)
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fr_parents = _get_parents(name, fr)
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to_parents = _get_parents(name, to)
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change = ChangeSet()
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if fr in to_parents:
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index = to_parents.index(fr) - 1
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while index >= 0:
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change.append(get_change_set(name, to_parents[index], False))
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index -= 1
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elif to in fr_parents:
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index = 0
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while index <= fr_parents.index(to) - 1:
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change.append(get_change_set(name, fr_parents[index], True))
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index += 1
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else:
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ancestor_index = -1
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while fr_parents[ancestor_index] == to_parents[ancestor_index]:
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ancestor_index -= 1
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ancestor = fr_parents[ancestor_index + 1]
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index = 0
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while index <= fr_parents.index(ancestor) - 1:
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change.append(get_change_set(name, fr_parents[index], True))
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index += 1
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index = to_parents.index(ancestor) - 1
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while index >= 0:
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change.append(get_change_set(name, to_parents[index], False))
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index -= 1
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return change.compress()
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