cppcheck: rework exclusion_file_list.py code

Rework the exclusion_file_list.py code to have the function
load_exclusion_file_list() detached from the xen-analysis.py tool,
in a way so that other modules can use the function.
The xen-analysis tool and in particular its module cppcheck_analysis.py
will use a new function cppcheck_exclusion_file_list().

No functional changes are intended.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/scripts/xen_analysis/cppcheck_analysis.py

@@ -2,7 +2,8 @@
 
 import os, re, shutil
 from . import settings, utils, cppcheck_report_utils, exclusion_file_list
-from .exclusion_file_list import ExclusionFileListError
+from .exclusion_file_list import (ExclusionFileListError,
+                                  cppcheck_exclusion_file_list)
 
 class GetMakeVarsPhaseError(Exception):
     pass
@@ -54,8 +55,7 @@ def __generate_suppression_list(out_file):
             try:
                 exclusion_file = \
                     "{}/docs/misra/exclude-list.json".format(settings.repo_dir)
-                exclusion_list = \
-                    exclusion_file_list.load_exclusion_file_list(exclusion_file)
+                exclusion_list = cppcheck_exclusion_file_list(exclusion_file)
             except ExclusionFileListError as e:
                 raise CppcheckDepsPhaseError(
                     "Issue with reading file {}: {}".format(exclusion_file, e)

xen/scripts/xen_analysis/exclusion_file_list.py

@@ -7,16 +7,24 @@ class ExclusionFileListError(Exception):
     pass
 
 
-def __cppcheck_path_exclude_syntax(path):
-    # Prepending * to the relative path to match every path where the Xen
-    # codebase could be
-    path = "*" + path
+def cppcheck_exclusion_file_list(input_file):
+    ret = []
+    excl_list = load_exclusion_file_list(input_file)
 
-    return path
+    for entry in excl_list:
+        # Prepending * to the relative path to match every path where the Xen
+        # codebase could be
+        ret.append("*" + entry[0])
+
+    return ret
 
 
-# Reads the exclusion file list and returns a list of relative path to be
-# excluded.
+# Reads the exclusion file list and returns an array containing a set where the
+# first entry is what was listed in the exclusion list file, and the second
+# entry is the absolute path of the first entry.
+# If the first entry contained a wildcard '*', the second entry will have an
+# array of the solved absolute path for that entry.
+# Returns [('path',[path,path,...]), ('path',[path,path,...]), ...]
 def load_exclusion_file_list(input_file):
     ret = []
     try:
@@ -58,13 +66,6 @@ def load_exclusion_file_list(input_file):
                     .format(path, filepath_object)
                 )
 
-        if settings.analysis_tool == "cppcheck":
-            path = __cppcheck_path_exclude_syntax(path)
-        else:
-            raise ExclusionFileListError(
-                "Unimplemented for {}!".format(settings.analysis_tool)
-            )
-
-        ret.append(path)
+        ret.append((path, check_path))
 
     return ret