core: add an Arch type (MR 2252)

Move pmb/parse/arch.py over to core and refactor it as an Arch type,
similar to how Chroot was done. Fix all the uses (that I can find) of
arch in the codebase that need adjusting.

The new Arch type is an Enum, making it clear what architectures can be
represented and making it much easier to reason about. Since we support
~5 (kinda) different representations of an Architecture (Alpine, Kernel,
target triple, platform, and QEMU), we now formalise that the Alpine
format is what we represent internally, with methods to convert to any
of the others as-needed.

Signed-off-by: Caleb Connolly <caleb@postmarketos.org>

pmb/sideload/__init__.py

@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 import os
 from typing import List
+from pmb.core.arch import Arch
 from pmb.helpers import logging
 import shlex
 
@@ -9,7 +10,6 @@ from pmb.types import PathString, PmbArgs
 import pmb.helpers.run
 import pmb.helpers.run_core
 import pmb.parse.apkindex
-import pmb.parse.arch
 import pmb.config.pmaports
 import pmb.build
 from pmb.core import get_context
@@ -39,7 +39,7 @@ def scp_abuild_key(args: PmbArgs, user: str, host: str, port: str):
     pmb.helpers.run.user(command, output="tui")
 
 
-def ssh_find_arch(args: PmbArgs, user: str, host: str, port: str) -> str:
+def ssh_find_arch(args: PmbArgs, user: str, host: str, port: str) -> Arch:
     """Connect to a device via ssh and query the architecture."""
     logging.info(f"Querying architecture of {user}@{host}")
     command = ["ssh", "-p", port, f"{user}@{host}", "uname -m"]
@@ -49,7 +49,7 @@ def ssh_find_arch(args: PmbArgs, user: str, host: str, port: str) -> str:
     output_lines = output.strip().splitlines()
     # Pick out last line which should contain the foreign device's architecture
     foreign_machine_type = output_lines[-1]
-    alpine_architecture = pmb.parse.arch.machine_type_to_alpine(foreign_machine_type)
+    alpine_architecture = Arch.from_machine_type(foreign_machine_type)
     return alpine_architecture
 
 
@@ -81,7 +81,7 @@ def ssh_install_apks(args: PmbArgs, user, host, port, paths):
     pmb.helpers.run.user(command, output="tui")
 
 
-def sideload(args: PmbArgs, user: str, host: str, port: str, arch: str, copy_key: bool, pkgnames):
+def sideload(args: PmbArgs, user: str, host: str, port: str, arch: Arch, copy_key: bool, pkgnames):
     """ Build packages if necessary and install them via SSH.
 
         :param user: target device ssh username