Implement document workflows transition ACLs. GitLab issue #321.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/document_states/api_views.py

@@ -6,7 +6,7 @@ from django.shortcuts import get_object_or_404
 from rest_framework import generics
 
 from acls.models import AccessControlList
-from documents.models import Document
+from documents.models import Document, DocumentType
 from documents.permissions import permission_document_type_view
 from permissions import Permission
 from rest_api.filters import MayanObjectPermissionsFilter
@@ -27,6 +27,33 @@ from .serializers import (
 )
 
 
+class APIDocumentTypeWorkflowListView(generics.ListAPIView):
+    serializer_class = WorkflowSerializer
+
+    def get(self, *args, **kwargs):
+        """
+        Returns a list of all the document type workflows.
+        """
+        return super(APIDocumentTypeWorkflowListView, self).get(*args, **kwargs)
+
+    def get_document_type(self):
+        document_type = get_object_or_404(DocumentType, pk=self.kwargs['pk'])
+
+        try:
+            Permission.check_permissions(
+                self.request.user, (permission_workflow_view,)
+            )
+        except PermissionDenied:
+            AccessControlList.objects.check_access(
+                permission_workflow_view, self.request.user, document_type
+            )
+
+        return document_type
+
+    def get_queryset(self):
+        return self.get_document_type().workflows.all()
+
+
 class APIWorkflowDocumentTypeList(generics.ListCreateAPIView):
     filter_backends = (MayanObjectPermissionsFilter,)
     mayan_object_permissions = {