docs: kdoc_files: allows the caller to use a different xforms class

While the main goal for kernel-doc is to be used inside the Linux
Kernel, other open source projects could benefit for it. That's
currently the case of QEMU, which has a fork, mainly due to two
reasons:

  - they need an extra C function transform rule;
  - they handle the html output a little bit different.

Add an extra optional argument to make easier for the code to be
shared, as, with that, QEMU can just create a new derivated class
that will contain its specific rulesets, and just copy the
remaining kernel-doc files as-is.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <6b274ddbdcd9d438c6848e00e410a2f65ef80ec2.1772810574.git.mchehab+huawei@kernel.org>

tools/lib/python/kdoc/kdoc_files.py

@@ -118,7 +118,7 @@ class KernelFiles():
         if fname in self.files:
             return
 
-        doc = KernelDoc(self.config, fname, CTransforms())
+        doc = KernelDoc(self.config, fname, self.xforms)
         export_table, entries = doc.parse_kdoc()
 
         self.export_table[fname] = export_table
@@ -154,7 +154,7 @@ class KernelFiles():
 
         self.error(f"Cannot find file {fname}")
 
-    def __init__(self, verbose=False, out_style=None,
+    def __init__(self, verbose=False, out_style=None, xforms=None,
                  werror=False, wreturn=False, wshort_desc=False,
                  wcontents_before_sections=False,
                  logger=None):
@@ -193,6 +193,11 @@ class KernelFiles():
         self.config.wshort_desc = wshort_desc
         self.config.wcontents_before_sections = wcontents_before_sections
 
+        if xforms:
+            self.xforms = xforms
+        else:
+            self.xforms = CTransforms()
+
         if not logger:
             self.config.log = logging.getLogger("kernel-doc")
         else: