Improve perforamance of _pluck_uniq_cols

src/formpack/utils/expand_content.py

@@ -11,6 +11,7 @@
 from .array_to_xpath import EXPANDABLE_FIELD_TYPES
 from .future import iteritems, OrderedDict
 from .iterator import get_first_occurrence
+from .ordered_set import OrderedSet
 from .replace_aliases import META_TYPES
 from .string import str_types
 from ..constants import (UNTRANSLATED, OR_OTHER_COLUMN,
@@ -158,7 +159,7 @@ def _get_special_survey_cols(content):
         'hint::English',
     For more examples, see tests.
     """
-    uniq_cols = OrderedDict()
+    uniq_cols = OrderedSet()
     special = OrderedDict()
 
     known_translated_cols = content.get('translated', [])
@@ -169,7 +170,7 @@ def _pluck_uniq_cols(sheet_name):
             # to be parsed and translated in a previous iteration
             _cols = [r for r in row.keys() if r not in known_translated_cols]
 
-            uniq_cols.update(OrderedDict.fromkeys(_cols))
+            uniq_cols.update(_cols)
 
     def _mark_special(**kwargs):
         column_name = kwargs.pop('column_name')
@@ -178,7 +179,7 @@ def _mark_special(**kwargs):
     _pluck_uniq_cols('survey')
     _pluck_uniq_cols('choices')
 
-    for column_name in uniq_cols.keys():
+    for column_name in uniq_cols:
         if column_name in ['label', 'hint']:
             _mark_special(column_name=column_name,
                           column=column_name,

src/formpack/utils/ordered_set.py

@@ -0,0 +1,45 @@
+import collections
+
+
+class OrderedSet(collections.MutableSet):
+    def __init__(self, iterable=None):
+        self.set = set()
+        self.list = []
+        if iterable is not None:
+            self |= iterable
+
+    def __len__(self):
+        return len(self.list)
+
+    def __contains__(self, key):
+        return key in self.set
+
+    def add(self, key):
+        if key not in self.set:
+            self.set.add(key)
+            self.list.append(key)
+
+    def update(self, keys):
+        for key in keys:
+            self.add(key)
+
+    def discard(self, key):
+        if key in self.set:
+            self.set.discard(key)
+            self.list.remove(key)
+
+    def __iter__(self):
+        curr = 0
+        while curr < len(self.list):
+            yield self.list[curr]
+            curr += 1
+
+    def __repr__(self):
+        if not self:
+            return '%s()' % (self.__class__.__name__,)
+        return '%s(%r)' % (self.__class__.__name__, list(self))
+
+    def __eq__(self, other):
+        if isinstance(other, OrderedSet):
+            return len(self) == len(other) and list(self) == list(other)
+        return set(self) == set(other)