Introduce pg.io for abstracted IO operations.

Details:
- Introduces `pg.io.File` and `pg.io.FileSystem`
- Introduces `pg.io.StdFileSystem` and `pg.io.MemoryFileSystem`.
- Introduces unified APIs for file access.
PiperOrigin-RevId: 584335843

docs/api/docgen.py

@@ -57,6 +57,7 @@
     'detouring',
     'geno',
     'hyper',
+    'io',
     'patching',
     'object_utils',
     'symbolic',

pyglove/core/__init__.py

@@ -48,8 +48,9 @@
 # pylint: disable=reimported
 # pylint: disable=g-import-not-at-top
 
+
 #
-# Symbols from 'symbolic.py'
+# Symbols from 'symbolic' sub-module.
 #
 
 
@@ -174,7 +175,7 @@
 WritePermissionError = symbolic.WritePermissionError
 
 #
-# Symbols from 'typing.py'
+# Symbols from 'typing' sub-module.
 #
 
 # NOTE(daiyip): we introduce 'typing' as an alias for 'schema' sub-module, since
@@ -195,7 +196,7 @@
 
 
 #
-# Symbols from 'geno.py'.
+# Symbols from 'geno' sub-module.
 #
 
 from pyglove.core import geno
@@ -208,7 +209,7 @@
 
 
 #
-# Symbols from 'hyper.py'.
+# Symbols from 'hyper' sub-module.
 #
 
 from pyglove.core import hyper
@@ -237,7 +238,7 @@
 
 
 #
-# Symbols from 'tuning.py'.
+# Symbols from 'tuning' sub-module.
 #
 
 from pyglove.core import tuning
@@ -246,15 +247,15 @@
 
 
 #
-# Symbols from 'detouring.py'
+# Symbols from 'detouring' sub-module.
 #
 
 from pyglove.core import detouring
 detour = detouring.detour
 
 
 #
-# Symbols from 'patching.py'.
+# Symbols from 'patching' sub-module.
 #
 
 from pyglove.core import patching
@@ -270,7 +271,7 @@
 
 
 #
-# Symbols from 'object_utils.py'.
+# Symbols from 'object_utils' sub-module.
 #
 
 from pyglove.core import object_utils
@@ -291,13 +292,19 @@
 docstr = object_utils.docstr
 catch_errors = object_utils.catch_errors
 
+#
+# Symbols from `io` sub-module.
+#
+
+from pyglove.core import io
+
+
 #
 # Symbols from `logging.py`.
 #
 
 from pyglove.core import logging
 
-
 # pylint: enable=g-import-not-at-top
 # pylint: enable=reimported
 # pylint: enable=unused-import

pyglove/core/io/__init__.py

@@ -0,0 +1,20 @@
+# Copyright 2023 The PyGlove Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Pluggable IO with unified interfaces."""
+
+# pylint: disable=g-bad-import-order
+
+from pyglove.core.io.file_system import *
+
+# pylint: enable=g-bad-import-order