generate_bom: Improve path prefix

In order to provide a more reliable path prefix and have additional
information regarding it, improve its calculation

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

scripts/generate_bom.py

@@ -228,17 +228,21 @@ class BomGenerator():
     # Used to get the path_prefix which should be removed before try to match
     # with the information in the copyright file
     # By doing this the chance of picking a default license is reduced
-    def get_path_prefix(self, copyright_info, units):
+    def get_path_prefix_and_depth(self, copyright_info, units):
         path_depth = self.get_copyright_path_depth(copyright_info)
         depths = path_depth.get_depths()
 
         for pd_key in reversed(depths):
             for un in units:
                 for p in path_depth.get_paths(pd_key):
-                    path_prefix_len = un['file_path'].find('/' + p + '/')
+                    if un['file_path'].startswith(p + '/'):
+                        return ('', pd_key)
+                    else:
+                        path_prefix_len = un['file_path'].find('/' + p + '/')
                     if path_prefix_len != -1:
-                        return un['file_path'][:path_prefix_len + 1]
-        return ''
+                        return (un['file_path'][:path_prefix_len + 1], pd_key)
+
+        return ('', -1)
 
     def scan_rust_unit(self, f_dir, f_src, copyright_info, out_licenses, out_copyright):
         # Rust files only have one compilation unit for the entire
@@ -292,7 +296,7 @@ class BomGenerator():
                 return {'binary_name': binary_name, 'binary_licenses': [NO_LICENSE_REPORT_FOUND], 'sources': sources}
 
         self.preprocess_unit(units)
-        path_prefix = self.get_path_prefix(package_copyright_files.primary_copyright, units)
+        (path_prefix, depth) = self.get_path_prefix_and_depth(package_copyright_files.primary_copyright, units)
 
         for un in units:
             file_copyright_info = package_copyright_files.find_copyright_for_path(un['comp_name'])