From 6ce7444669c7462e26875bb6772838dab0df3cb5 Mon Sep 17 00:00:00 2001
From: Ankush Menat <ankush@frappe.io>
Date: Fri, 2 Jun 2023 22:29:05 +0530
Subject: [PATCH] refactor: generic callback manager

---
 frappe/database/database.py | 48 +++++--------------------------------
 frappe/utils/__init__.py    | 42 +++++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 43 deletions(-)

diff --git a/frappe/database/database.py b/frappe/database/database.py
index e11e2fccbd..bd99f790f4 100644
--- a/frappe/database/database.py
+++ b/frappe/database/database.py
@@ -8,10 +8,9 @@ import random
 import re
 import string
 import traceback
-from collections import deque
 from contextlib import contextmanager, suppress
 from time import time
-from typing import Any, Callable, Iterable, Sequence
+from typing import Any, Iterable, Sequence
 
 from pypika.dialects import MySQLQueryBuilder, PostgreSQLQueryBuilder
 from pypika.terms import Criterion, NullValue
@@ -32,6 +31,7 @@ from frappe.database.utils import (
 from frappe.exceptions import DoesNotExistError, ImplicitCommitError
 from frappe.model.utils.link_count import flush_local_link_count
 from frappe.query_builder.functions import Count
+from frappe.utils import CallbackManager
 from frappe.utils import cast as cast_fieldtype
 from frappe.utils import cint, get_datetime, get_table_name, getdate, now, sbool
 from frappe.utils.deprecations import deprecated, deprecation_warning
@@ -109,10 +109,10 @@ class Database:
 		self.logger = frappe.logger("database")
 		self.logger.setLevel("WARNING")
 
-		self.before_commit = DBHooks()
-		self.after_commit = DBHooks()
-		self.before_rollback = DBHooks()
-		self.after_rollback = DBHooks()
+		self.before_commit = CallbackManager()
+		self.after_commit = CallbackManager()
+		self.before_rollback = CallbackManager()
+		self.after_rollback = CallbackManager()
 
 		# self.db_type: str
 		# self.last_query (lazy) attribute of last sql query executed
@@ -1310,42 +1310,6 @@ class Database:
 		raise NotImplementedError
 
 
-class DBHooks:
-	"""Hooks for database events.
-
-	Primarily used for doing things before/after commit/rollback.
-
-	hook_manager = DBHooks()
-
-	# Put a function call in queue
-	hook_manager.add(func)
-
-	# Run all pending functions in queue
-	hook_manager.run()
-
-	# Reset quue
-	hook_manager.reset()
-	"""
-
-	__slots__ = ("_functions",)
-
-	def __init__(self) -> None:
-		self._functions = deque()
-
-	def add(self, func: Callable) -> None:
-		"""Add a function to queue, functions are executed in order of addition."""
-		self._functions.append(func)
-
-	def run(self):
-		"""Run all functions in queue"""
-		while self._functions:
-			_func = self._functions.popleft()
-			_func()
-
-	def reset(self):
-		self._functions = deque()
-
-
 @contextmanager
 def savepoint(catch: type | tuple[type, ...] = Exception):
 	"""Wrapper for wrapping blocks of DB operations in a savepoint.
diff --git a/frappe/utils/__init__.py b/frappe/utils/__init__.py
index ef32ff5653..b7dc565555 100644
--- a/frappe/utils/__init__.py
+++ b/frappe/utils/__init__.py
@@ -9,6 +9,7 @@ import os
 import re
 import sys
 import traceback
+from collections import deque
 from collections.abc import (
 	Container,
 	Generator,
@@ -20,7 +21,7 @@ from collections.abc import (
 from email.header import decode_header, make_header
 from email.utils import formataddr, parseaddr
 from gzip import GzipFile
-from typing import Any, Literal
+from typing import Any, Callable, Literal
 from urllib.parse import quote, urlparse
 
 from redis.exceptions import ConnectionError
@@ -1092,3 +1093,42 @@ def is_git_url(url: str) -> bool:
 	# modified to allow without the tailing .git from https://github.com/jonschlinkert/is-git-url.git
 	pattern = r"(?:git|ssh|https?|\w*@[-\w.]+):(\/\/)?(.*?)(\.git)?(\/?|\#[-\d\w._]+?)$"
 	return bool(re.match(pattern, url))
+
+
+class CallbackManager:
+	"""Manage callbacks.
+
+	```
+	# Capture callacks
+	callbacks = CallbackManager()
+
+	# Put a function call in queue
+	callbacks.add(func)
+
+	# Run all pending functions in queue
+	callbacks.run()
+
+	# Reset queue
+	callbacks.reset()
+	```
+
+	Example usage: frappe.db.after_commit
+	"""
+
+	__slots__ = ("_functions",)
+
+	def __init__(self) -> None:
+		self._functions = deque()
+
+	def add(self, func: Callable) -> None:
+		"""Add a function to queue, functions are executed in order of addition."""
+		self._functions.append(func)
+
+	def run(self):
+		"""Run all functions in queue"""
+		while self._functions:
+			_func = self._functions.popleft()
+			_func()
+
+	def reset(self):
+		self._functions.clear()