Add --only-builtin falg for scancode-reindex-licenses

Signed-off-by: Ayan Sinha Mahapatra <ayansmahapatra@gmail.com>

src/licensedcode/cache.py

@@ -6,9 +6,10 @@
 # See https://github.com/nexB/scancode-toolkit for support or download.
 # See https://aboutcode.org for more information about nexB OSS projects.
 #
-import click
+
 import os
 import pickle
+from shutil import rmtree
 
 import attr
 
@@ -53,6 +54,7 @@ class LicenseCache:
 
     @staticmethod
     def load_or_build(
+        only_builtin=False,
         licensedcode_cache_dir=licensedcode_cache_dir,
         scancode_cache_dir=scancode_cache_dir,
         force=False,
@@ -81,6 +83,9 @@ def load_or_build(
           directories using the same format that we use for licenses and rules.
         """
         idx_cache_dir = os.path.join(licensedcode_cache_dir, LICENSE_INDEX_DIR)
+        if only_builtin:
+            rmtree(idx_cache_dir)
+
         create_dir(idx_cache_dir)
         cache_file = os.path.join(idx_cache_dir, LICENSE_INDEX_FILENAME)
 
@@ -119,15 +124,19 @@ def load_or_build(
                 # Here, the cache is either stale or non-existing: we need to
                 # rebuild all cached data (e.g. mostly the index) and cache it
 
-                additional_directories = []
-                plugin_directories = get_paths_to_installed_licenses_and_rules()
-                if plugin_directories:
-                    additional_directories.extend(plugin_directories)
+                if only_builtin:
+                    additional_directory = None
+                    additional_directories = []
+                    plugin_directories = []
+                else:
+                    plugin_directories = get_paths_to_installed_licenses_and_rules()
+                    if plugin_directories:
+                        additional_directories.extend(plugin_directories)
 
-                # include installed licenses
-                if additional_directory:
-                    # additional_directories is originally a tuple
-                    additional_directories.append(additional_directory)
+                    # include installed licenses
+                    if additional_directory:
+                        # additional_directories is originally a tuple
+                        additional_directories.append(additional_directory)
 
                 additional_license_dirs = get_license_dirs(additional_dirs=additional_directories)
                 validate_additional_license_data(
@@ -355,7 +364,12 @@ def build_unknown_spdx_symbol(licenses_db=None):
     return LicenseSymbolLike(licenses_db['unknown-spdx'])
 
 
-def get_cache(force=False, index_all_languages=False, additional_directory=None):
+def get_cache(
+    only_builtin=False,
+    force=False,
+    index_all_languages=False,
+    additional_directory=None
+):
     """
     Return a LicenseCache either rebuilt, cached or loaded from disk.
 
@@ -364,20 +378,27 @@ def get_cache(force=False, index_all_languages=False, additional_directory=None)
     texts and rules (the default)
     """
     return populate_cache(
+        only_builtin=only_builtin,
         force=force,
         index_all_languages=index_all_languages,
         additional_directory=additional_directory,
     )
 
 
-def populate_cache(force=False, index_all_languages=False, additional_directory=None):
+def populate_cache(
+    only_builtin=False,
+    force=False,
+    index_all_languages=False,
+    additional_directory=None
+):
     """
     Return, load or build and cache a LicenseCache.
     """
     global _LICENSE_CACHE
 
     if force or not _LICENSE_CACHE:
         _LICENSE_CACHE = LicenseCache.load_or_build(
+            only_builtin=only_builtin,
             licensedcode_cache_dir=licensedcode_cache_dir,
             scancode_cache_dir=scancode_cache_dir,
             force=force,
@@ -407,11 +428,17 @@ def load_cache_file(cache_file):
             raise Exception(msg) from e
 
 
-def get_index(force=False, index_all_languages=False, additional_directory=None):
+def get_index(
+    only_builtin=False,
+    force=False,
+    index_all_languages=False,
+    additional_directory=None
+):
     """
     Return and eventually build and cache a LicenseIndex.
     """
     return get_cache(
+        only_builtin=only_builtin,
         force=force,
         index_all_languages=index_all_languages,
         additional_directory=additional_directory

src/licensedcode/reindex.py

@@ -9,23 +9,39 @@
 
 import click
 
+from commoncode.cliutils import PluggableCommandLineOption
+
 
 @click.command(name='scancode-reindex-licenses')
 @click.option(
     '--all-languages',
     is_flag=True,
     help='[EXPERIMENTAL] Rebuild the license index including texts all '
             'languages (and not only English) and exit.',
+    cls=PluggableCommandLineOption,
+)
+@click.option(
+    '--only-builtin',
+    is_flag=True,
+    help='Rebuild the license index excluding any additional '
+         'license directory or additional license plugins which'
+         'were added previously, i.e. with only builtin scancode '
+         'license and rules.',
+    conflicting_options=['additional_directory'],
+    cls=PluggableCommandLineOption,
 )
 @click.option(
     '--additional-directory',
     type=click.Path(exists=True, readable=True, file_okay=False, resolve_path=True, path_type=str),
     metavar='DIR',
     help='Include this directory with additional custom licenses and license rules '
             'in the license detection index.',
+    conflicting_options=['only_builtin'],
+    cls=PluggableCommandLineOption,
 )
 @click.help_option('-h', '--help')
 def reindex_licenses(
+    only_builtin,
     all_languages,
     additional_directory,
     *args,
@@ -35,7 +51,12 @@ def reindex_licenses(
 
     from licensedcode.cache import get_index
     click.echo('Rebuilding the license index...')
-    get_index(force=True, index_all_languages=bool(all_languages), additional_directory=additional_directory)
+    get_index(
+        only_builtin=only_builtin,
+        force=True,
+        index_all_languages=bool(all_languages),
+        additional_directory=additional_directory
+    )
     click.echo('Done.')