LoadSVD: Load SVD from ZIP file instead of pkg_resources

This changes the logic with `svd_load <VENDOR> <MODEL>` to not search in
the pkg_resources of Python module `cmsis_svd.data` but instead search
in a ZIP file at `$CMSIS_SVD_ZIPFILE` if that environment variable is
defined, otherwise it looks `$XDG_CACHE_HOME/cmdebug/cmsis-svd-data.zip`
with `$XDG_CACHE_HOME` falling back to `~/.cache` if not found in the
environment.

As of 2025-11-09, the `HEAD` of https://github.com/cmsis-svd/cmsis-svd-data
is 5.8 GiB in size uncompressed, or 254 MiB when zipped. Personally, I
do not perceive any additional latency by having to unzip the chosen
SVD file first.

Author: maribu

cmdebug/svd_gdb.py

@@ -16,11 +16,15 @@
 """
 
 import gdb
-import re
 import math
-import sys
+import pathlib
+import re
 import struct
-import pkg_resources
+import sys
+import tempfile
+import zipfile
+
+from os import environ
 
 sys.path.append('.')
 from cmdebug.svd import SVDFile
@@ -31,6 +35,16 @@
     32: "I",
 }
 
+if "XDG_CACHE_HOME" in environ and environ["XDG_CACHE_HOME"] != "":
+    CACHE_DIR = pathlib.Path.joinpath(environ["XDG_CACHE_HOME"], "cmdebug")
+else:
+    CACHE_DIR = pathlib.Path.joinpath(pathlib.Path.home(), ".cache", "cmdebug")
+
+if "CMSIS_SVD_ZIPFILE" in environ and environ["CMSIS_SVD_ZIPFILE"] != "":
+    CMSIS_SVD_ZIPFILE = pathlib.Path(environ("CMSIS_SVD_ZIPFILE"))
+else:
+    CMSIS_SVD_ZIPFILE = pathlib.Path.joinpath(CACHE_DIR, "cmsis-svd-data.zip")
+
 
 class LoadSVD(gdb.Command):
     """ A command to load an SVD file and to create the command for inspecting
@@ -40,11 +54,16 @@ class LoadSVD(gdb.Command):
     def __init__(self):
         self.vendors = {}
         try:
-            vendor_names = pkg_resources.resource_listdir("cmsis_svd", "data")
-            for vendor in vendor_names:
-                fnames = pkg_resources.resource_listdir("cmsis_svd", "data/{}".format(vendor))
-                self.vendors[vendor] = [fname for fname in fnames if fname.lower().endswith(".svd")]
-        except:
+            with zipfile.ZipFile(CMSIS_SVD_ZIPFILE, mode='r') as svdzip:
+                for entry in svdzip.namelist():
+                    if entry.lower().endswith(".svd"):
+                        p = pathlib.Path(entry)
+                        vendor = p.parent.name
+                        model = p.name[:-4]
+                        if vendor not in self.vendors:
+                            self.vendors[vendor] = list()
+                        self.vendors[vendor].append(model)
+        except FileNotFoundError:
             pass
 
         if len(self.vendors) > 0:
@@ -75,12 +94,25 @@ def complete(self, text, word):
     def invoke(args, from_tty):
         args = gdb.string_to_argv(args)
         argc = len(args)
+        f = None
         if argc == 1:
             gdb.write("Loading SVD file {}...\n".format(args[0]))
             f = args[0]
         elif argc == 2:
             gdb.write("Loading SVD file {}/{}...\n".format(args[0], args[1]))
-            f = pkg_resources.resource_filename("cmsis_svd", "data/{}/{}".format(args[0], args[1]))
+            name = args[0].lower() + "/" + args[1].lower() + ".svd"
+            try:
+                with zipfile.ZipFile(CMSIS_SVD_ZIPFILE, mode='r') as svdzip:
+                    for entry in svdzip.namelist():
+                        lower = entry.lower()
+                        if lower == name or lower.endswith("/" + name):
+                            f = svdzip.extract(entry, path=tempfile.TemporaryDirectory().name)
+                            break
+            except FileNotFoundError:
+                raise gdb.GdbError(f"Could not open \"{CMSIS_SVD_ZIPFILE}\"")
+
+            if f is None:
+                raise gdb.GdbError(f"Could not find SVD for \"{args[0]}/{args[1]}\" in \"{CMSIS_SVD_ZIPFILE}\": No case-insensitive match for \"**/{name}\"")
         else:
             raise gdb.GdbError("Usage: svd_load <vendor> <device.svd> or svd_load <path/to/filename.svd>\n")
         try: