Move SPDX license check to spdx_common

Previously `is_spdx_license_expression` method was duplicated in
both tag/value and json package_helpers. This change moves it to
`spdx_common` for general use

Signed-off-by: Ivana Atanasova <[email protected]>

Author: ivanayov

tern/formats/spdx/spdx_common.py

@@ -13,6 +13,7 @@
 import re
 import uuid
 
+from license_expression import get_spdx_licensing
 from tern.utils import constants
 from tern.formats.spdx.spdxtagvalue import formats as spdx_formats
 
@@ -43,6 +44,14 @@ def get_license_ref(license_string):
     """ For SPDX tag-value format, return a LicenseRef string """
     return 'LicenseRef-' + get_string_id(license_string)
 
+def is_spdx_license_expression(license_data):
+    '''Return True if the license is a valid SPDX license expression, else
+    return False'''
+    licensing = get_spdx_licensing()
+    if ',' in license_data:
+        license_data = license_data.replace(',', ' ')
+    return licensing.validate(license_data).errors == []
+
 
 ########################
 # Common Image Helpers #

tern/formats/spdx/spdxjson/package_helpers.py

@@ -7,21 +7,11 @@
 Helper functions for packages in SPDX JSON document creation
 """
 
-from license_expression import get_spdx_licensing
 from tern.report import content
 from tern.formats.spdx import spdx_common
 from tern.formats.spdx.spdxjson import formats as json_formats
 
 
-def is_spdx_license_expression(license_data):
-    '''Return True if the license is a valid SPDX license expression, else
-    return False'''
-    licensing = get_spdx_licensing()
-    if ',' in license_data:
-        license_data = license_data.replace(',', ' ')
-    return licensing.validate(license_data).errors == []
-
-
 def get_package_comment(package):
     '''Given a package object, return a PackageComment string for a list of
     NoticeOrigin objects'''
@@ -35,7 +25,7 @@ def get_package_comment(package):
 
 def get_package_license_declared(package_license_declared):
     if package_license_declared:
-        if is_spdx_license_expression(package_license_declared):
+        if spdx_common.is_spdx_license_expression(package_license_declared):
             return package_license_declared
         return spdx_common.get_license_ref(package_license_declared)
     return 'NONE'

tern/formats/spdx/spdxtagvalue/package_helpers.py

@@ -7,20 +7,11 @@
 Helper functions for packages in SPDX document
 """
 
-from license_expression import get_spdx_licensing
 from tern.formats.spdx.spdxtagvalue import formats as spdx_formats
 from tern.formats.spdx import spdx_common
 from tern.report import content
 
 
-def is_spdx_license_expression(license_data):
-    '''Return True if the license is a valid SPDX license expression, else
-    return False'''
-    licensing = get_spdx_licensing()
-    if ',' in license_data:
-        license_data = license_data.replace(',', ' ')
-    return licensing.validate(license_data).errors == []
-
 def get_package_comment(package_obj):
     '''Return a PackageComment tag-value text block for a list of
     NoticeOrigin objects'''
@@ -35,7 +26,7 @@ def get_package_comment(package_obj):
 
 def get_package_license_declared(package_license_declared):
     if package_license_declared:
-        if is_spdx_license_expression(package_license_declared):
+        if spdx_common.is_spdx_license_expression(package_license_declared):
             return package_license_declared
         return spdx_common.get_license_ref(package_license_declared)
     return 'NONE'