From 5acb0aaf0529e5efb32c950e0d77a830a40fc06e Mon Sep 17 00:00:00 2001
From: tangkong <tangkongrobert@gmail.com>
Date: Fri, 10 Jan 2025 16:05:08 -0800
Subject: [PATCH 1/2] PERF: delay preset sync until tab completion is accessed

---
 pcdsdevices/interface.py       | 29 +++++++++++++++++++----------
 pcdsdevices/tests/test_lens.py |  3 +++
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/pcdsdevices/interface.py b/pcdsdevices/interface.py
index a139fdd4669..e50459aff67 100644
--- a/pcdsdevices/interface.py
+++ b/pcdsdevices/interface.py
@@ -227,8 +227,13 @@ def __init_subclass__(cls, **kwargs):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._tab = self._class_tab.new_instance(self)
+        self._tab_initialized = False
 
     def __dir__(self):
+        if not self._tab_initialized and hasattr(self, 'presets'):
+            self._tab_initialized = True
+            self.presets.sync()
+
         return self._tab.get_dir()
 
     def __repr__(self):
@@ -1085,16 +1090,19 @@ def sync(self):
         self._remove_methods()
         self._cache = {}
         logger.debug('filling %s cache', self.name)
-        for preset_type in self._paths.keys():
-            path = self._path(preset_type)
-            if path.exists():
-                try:
-                    self._cache[preset_type] = self._read(preset_type)
-                except BlockingIOError:
-                    self._log_flock_error()
-            else:
-                logger.debug('No %s preset file for %s',
-                             preset_type, self._device.name)
+
+        # only consult files if tab-completion has been attempted
+        if self._device._tab_initialized:
+            for preset_type in self._paths.keys():
+                path = self._path(preset_type)
+                if path.exists():
+                    try:
+                        self._cache[preset_type] = self._read(preset_type)
+                    except BlockingIOError:
+                        self._log_flock_error()
+                else:
+                    logger.debug('No %s preset file for %s',
+                                 preset_type, self._device.name)
         self._create_methods()
 
     def _log_flock_error(self):
@@ -1140,6 +1148,7 @@ def _register_method(self, obj, method_name, method):
         self._methods.append((obj, method_name))
         setattr(obj, method_name, MethodType(method, obj))
         if hasattr(obj, '_tab'):
+            # obj._tab: TabCompletionHelperInstance
             obj._tab.add(method_name)
 
     def _make_add(self, preset_type):
diff --git a/pcdsdevices/tests/test_lens.py b/pcdsdevices/tests/test_lens.py
index 39bea9e5040..050a4612eef 100644
--- a/pcdsdevices/tests/test_lens.py
+++ b/pcdsdevices/tests/test_lens.py
@@ -116,6 +116,9 @@ def fake_lensstack(fake_att):
                                   E=sample_E,
                                   z_offset=.01, z_dir=1, att_obj=fake_att,
                                   lcls_obj=.01, mono_obj=.01)
+    # "activate" tab completion
+    for attr in ['x', 'y', 'z']:
+        getattr(fake_lensstack, attr)._tab_initialized = True
     return fake_lensstack
 
 

From 61fe0197c3ab6fa2ac9f0746923d690f89e03db7 Mon Sep 17 00:00:00 2001
From: tangkong <tangkongrobert@gmail.com>
Date: Fri, 10 Jan 2025 16:54:48 -0800
Subject: [PATCH 2/2] MNT: make deferred loading of presets optional

---
 pcdsdevices/interface.py       | 18 +++++++++++-------
 pcdsdevices/tests/test_lens.py |  3 ---
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/pcdsdevices/interface.py b/pcdsdevices/interface.py
index e50459aff67..f8d7f3962b8 100644
--- a/pcdsdevices/interface.py
+++ b/pcdsdevices/interface.py
@@ -904,7 +904,7 @@ def set_position(self, position):
         self.set_current_position(position)
 
 
-def setup_preset_paths(**paths):
+def setup_preset_paths(**kwargs):
     """
     Prepare the :class:`Presets` class.
 
@@ -912,17 +912,21 @@ def setup_preset_paths(**paths):
 
     Parameters
     ----------
-    **paths : str keyword args
+    **kwargs: str keyword args
         A mapping from type of preset to destination path. These will be
         directories that contain the yaml files that define the preset
         positions.
-    """
 
+        (Optional) "defer_loading": bool, whether or not to defer the loading
+        of preset files until the first tab completion
+    """
+    defer_loading = kwargs.pop("defer_loading", False)
+    paths = kwargs
     Presets._paths = {}
     for k, v in paths.items():
         Presets._paths[k] = Path(v)
     for preset in Presets._registry:
-        preset.sync()
+        preset.sync(defer_loading=defer_loading)
 
 
 class Presets:
@@ -1084,15 +1088,15 @@ def _update(self, preset_type, name, value=None, comment=None,
         except BlockingIOError:
             self._log_flock_error()
 
-    def sync(self):
+    def sync(self, defer_loading: bool = False):
         """Synchronize the presets with the database."""
         logger.debug('call %s presets.sync()', self._device.name)
         self._remove_methods()
         self._cache = {}
         logger.debug('filling %s cache', self.name)
 
-        # only consult files if tab-completion has been attempted
-        if self._device._tab_initialized:
+        # only consult files if requested
+        if not defer_loading:
             for preset_type in self._paths.keys():
                 path = self._path(preset_type)
                 if path.exists():
diff --git a/pcdsdevices/tests/test_lens.py b/pcdsdevices/tests/test_lens.py
index 050a4612eef..39bea9e5040 100644
--- a/pcdsdevices/tests/test_lens.py
+++ b/pcdsdevices/tests/test_lens.py
@@ -116,9 +116,6 @@ def fake_lensstack(fake_att):
                                   E=sample_E,
                                   z_offset=.01, z_dir=1, att_obj=fake_att,
                                   lcls_obj=.01, mono_obj=.01)
-    # "activate" tab completion
-    for attr in ['x', 'y', 'z']:
-        getattr(fake_lensstack, attr)._tab_initialized = True
     return fake_lensstack