treewide: add a Chroot type and adopt pathlib.Path (MR 2252)

Introduce a new module: pmb.core to contain explicitly typed pmbootstrap
API. The first component being Suffix and SuffixType. This explicitly
defines what suffixes are possible, future changes should aim to further
constrain this API (e.g. by validating against available device
codenames or architectures for buildroot suffixes).

Additionally, migrate the entire codebase over to using pathlib.Path.
This is a relatively new part of the Python standard library that uses a
more object oriented model for path handling. It also uses strong type
hinting and has other features that make it much cleaner and easier to
work with than pure f-strings. The Chroot class overloads the "/"
operator the same way the Path object does, allowing one to write paths
relative to a given chroot as:

builddir = chroot / "home/pmos/build"

The Chroot class also has a string representation ("native", or
"rootfs_valve-jupiter"), and a .path property for directly accessing the
absolute path (as a Path object).

The general idea here is to encapsulate common patterns into type hinted
code, and gradually reduce the amount of assumptions made around the
codebase so that future changes are easier to implement.

As the chroot suffixes are now part of the Chroot class, we also
implement validation for them, this encodes the rules on suffix naming
and will cause a runtime exception if a suffix doesn't follow the rules.

pmb/helpers/devices.py

@@ -2,17 +2,19 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 import os
 import glob
+from pathlib import Path
+from pmb.core.types import PmbArgs
 import pmb.parse
 
 
-def find_path(args, codename, file=''):
+def find_path(args: PmbArgs, codename: str, file='') -> Path:
     """Find path to device APKBUILD under `device/*/device-`.
 
     :param codename: device codename
     :param file: file to look for (e.g. APKBUILD or deviceinfo), may be empty
     :returns: path to APKBUILD
     """
-    g = glob.glob(args.aports + "/device/*/device-" + codename + '/' + file)
+    g = list((args.aports / "device").glob(f"*/device-{codename}/{file}"))
     if not g:
         return None
 
@@ -23,7 +25,7 @@ def find_path(args, codename, file=''):
     return g[0]
 
 
-def list_codenames(args, vendor=None, archived=True):
+def list_codenames(args: PmbArgs, vendor=None, archived=True):
     """Get all devices, for which aports are available.
 
     :param vendor: vendor name to choose devices from, or None for all vendors
@@ -31,8 +33,8 @@ def list_codenames(args, vendor=None, archived=True):
     :returns: ["first-device", "second-device", ...]
     """
     ret = []
-    for path in glob.glob(args.aports + "/device/*/device-*"):
-        if not archived and '/archived/' in path:
+    for path in args.aports.glob("device/*/device-*"):
+        if not archived and 'archived' in path.parts:
             continue
         device = os.path.basename(path).split("-", 1)[1]
         if (vendor is None) or device.startswith(vendor + '-'):
@@ -40,19 +42,19 @@ def list_codenames(args, vendor=None, archived=True):
     return ret
 
 
-def list_vendors(args):
+def list_vendors(args: PmbArgs):
     """Get all device vendors, for which aports are available.
 
     :returns: {"vendor1", "vendor2", ...}
     """
     ret = set()
-    for path in glob.glob(args.aports + "/device/*/device-*"):
-        vendor = os.path.basename(path).split("-", 2)[1]
+    for path in (args.aports / "device").glob("*/device-*"):
+        vendor = path.name.split("-", 2)[1]
         ret.add(vendor)
     return ret
 
 
-def list_apkbuilds(args):
+def list_apkbuilds(args: PmbArgs):
     """:returns: { "first-device": {"pkgname": ..., "pkgver": ...}, ... }"""
     ret = {}
     for device in list_codenames(args):
@@ -61,7 +63,7 @@ def list_apkbuilds(args):
     return ret
 
 
-def list_deviceinfos(args):
+def list_deviceinfos(args: PmbArgs):
     """:returns: { "first-device": {"name": ..., "screen_width": ...}, ... }"""
     ret = {}
     for device in list_codenames(args):