Implement operation tree in database

api/operation.py

@@ -0,0 +1,76 @@
+from psycopg.rows import dict_row
+from api.connection import g_conn_dict as conn
+
+def _get_current_operation(name: str) -> int:
+    with conn[name].cursor(row_factory=dict_row) as cur:
+        cur.execute(f"select id from current_operation")
+        return int(cur.fetchone()['id'])
+
+def _update_current_operation(name: str, old_id: int, id: int) -> None:
+    with conn[name].cursor() as cur:
+        cur.execute(f"update current_operation set id = {id} where id = {old_id}")
+
+def _add_redo_undo(name: str, redo: str, undo: str) -> int:
+    with conn[name].cursor(row_factory=dict_row) as cur:
+        cur.execute("select max(id) from operation")
+        parent = int(cur.fetchone()['max'])
+        cur.execute(f"insert into operation (id, redo, undo, parent) values (default, '{redo}', '{undo}', {parent})")
+        return parent + 1
+
+# execute curr undo
+def _query_undo(name: str, id: str) -> dict[str, str]:
+    with conn[name].cursor(row_factory=dict_row) as cur:
+        cur.execute(f"select undo, parent from operation where id = {id}")
+        return cur.fetchone()
+
+# execute next redo
+def _query_redo_child(name: str, id: str) -> str:
+    with conn[name].cursor(row_factory=dict_row) as cur:
+        cur.execute(f"select redo_child from operation where id = {id}")
+        return cur.fetchone()['redo_child']
+
+def _query_redo(name: str, id: str) -> dict[str, str]:
+    with conn[name].cursor(row_factory=dict_row) as cur:
+        cur.execute(f"select redo from operation where id = {id}")
+        return cur.fetchone()['redo']
+
+def _set_redo_child(name: str, id: str, child:str) -> None:
+    with conn[name].cursor() as cur:
+        cur.execute(f"update operation set redo_child = {child} where id = {id}")
+
+def _execute(name: str, sql: str) -> None:
+    with conn[name].cursor() as cur:
+        sql = sql.replace("\"", "\'")
+        cur.execute(sql)
+
+def add_operation(name: str, redo: str, undo: str) -> None:
+    curr = _add_redo_undo(name, redo, undo)
+    old = _get_current_operation(name)
+    _update_current_operation(name, old, curr)
+
+def execute_undo(name: str) -> None:
+    curr = _get_current_operation(name)
+    row = _query_undo(name, curr)
+    undo = row['undo']
+    if undo == '':
+        print("nothing to undo!")
+        return
+
+    parent = int(row['parent'])
+    _set_redo_child(name, parent, curr)
+
+    _execute(name, undo)
+    _update_current_operation(name, curr, parent)
+
+def execute_redo(name: str) -> None:
+    curr = _get_current_operation(name)
+    redoChild = _query_redo_child(name, curr)
+    if redoChild == None:
+        print("nothing to redo!")
+        return
+    
+    child = int(redoChild)
+    redo = _query_redo(name, child)
+
+    _execute(name, redo)
+    _update_current_operation(name, curr, child)

api/test/operation.py

@@ -0,0 +1,25 @@
+from api.project import *
+from api.s0_base import *
+
+p = "test_operation"
+
+if is_project_open(p):
+    close_project(p)
+
+if have_project(p):
+    delete_project(p)
+
+create_project(p)
+open_project(p)
+
+add_node(p, "n-1", JUNCTION)
+add_node(p, "n-2", JUNCTION)
+add_node(p, "n-3", JUNCTION)
+execute_undo(p)
+add_node(p, "n-3", JUNCTION)
+add_node(p, "n-4", JUNCTION)
+execute_undo(p)
+execute_redo(p)
+
+close_project(p)
+delete_project(p)