Update code and tests to support the 'bytes_le' attribute (for

little-endian byte order on Windows), and to work around clocks
with low resolution yielding duplicate UUIDs.

Anthony Baxter has approved this change.

2 files changed, 104 insertions, 53 deletions

diff --git a/Lib/test/test_uuid.py b/Lib/test/test_uuid.py
index 0586cfd..06ec51d 100644
--- a/Lib/test/test_uuid.py
+++ b/Lib/test/test_uuid.py
@@ -16,12 +16,13 @@ class TestUUID(TestCase):
     def test_UUID(self):
         equal = self.assertEqual
         ascending = []
-        for (string, curly, hex, bytes, fields, integer, urn,
+        for (string, curly, hex, bytes, bytes_le, fields, integer, urn,
              time, clock_seq, variant, version) in [
             ('00000000-0000-0000-0000-000000000000',
              '{00000000-0000-0000-0000-000000000000}',
              '00000000000000000000000000000000',
              '\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0',
+             '\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0',
              (0, 0, 0, 0, 0, 0),
              0,
              'urn:uuid:00000000-0000-0000-0000-000000000000',
@@ -30,6 +31,7 @@ class TestUUID(TestCase):
              '{00010203-0405-0607-0809-0a0b0c0d0e0f}',
              '000102030405060708090a0b0c0d0e0f',
              '\0\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\x0d\x0e\x0f',
+             '\x03\x02\x01\0\x05\x04\x07\x06\x08\t\n\x0b\x0c\x0d\x0e\x0f',
              (0x00010203L, 0x0405, 0x0607, 8, 9, 0x0a0b0c0d0e0fL),
              0x000102030405060708090a0b0c0d0e0fL,
              'urn:uuid:00010203-0405-0607-0809-0a0b0c0d0e0f',
@@ -38,6 +40,7 @@ class TestUUID(TestCase):
              '{02d9e6d5-9467-382e-8f9b-9300a64ac3cd}',
              '02d9e6d59467382e8f9b9300a64ac3cd',
              '\x02\xd9\xe6\xd5\x94\x67\x38\x2e\x8f\x9b\x93\x00\xa6\x4a\xc3\xcd',
+             '\xd5\xe6\xd9\x02\x67\x94\x2e\x38\x8f\x9b\x93\x00\xa6\x4a\xc3\xcd',
              (0x02d9e6d5L, 0x9467, 0x382e, 0x8f, 0x9b, 0x9300a64ac3cdL),
              0x02d9e6d59467382e8f9b9300a64ac3cdL,
              'urn:uuid:02d9e6d5-9467-382e-8f9b-9300a64ac3cd',
@@ -46,6 +49,7 @@ class TestUUID(TestCase):
              '{12345678-1234-5678-1234-567812345678}',
              '12345678123456781234567812345678',
              '\x12\x34\x56\x78'*4,
+             '\x78\x56\x34\x12\x34\x12\x78\x56\x12\x34\x56\x78\x12\x34\x56\x78',
              (0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678),
              0x12345678123456781234567812345678,
              'urn:uuid:12345678-1234-5678-1234-567812345678',
@@ -54,6 +58,7 @@ class TestUUID(TestCase):
              '{6ba7b810-9dad-11d1-80b4-00c04fd430c8}',
              '6ba7b8109dad11d180b400c04fd430c8',
              '\x6b\xa7\xb8\x10\x9d\xad\x11\xd1\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
+             '\x10\xb8\xa7\x6b\xad\x9d\xd1\x11\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
              (0x6ba7b810L, 0x9dad, 0x11d1, 0x80, 0xb4, 0x00c04fd430c8L),
              0x6ba7b8109dad11d180b400c04fd430c8L,
              'urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8',
@@ -62,6 +67,7 @@ class TestUUID(TestCase):
              '{6ba7b811-9dad-11d1-80b4-00c04fd430c8}',
              '6ba7b8119dad11d180b400c04fd430c8',
              '\x6b\xa7\xb8\x11\x9d\xad\x11\xd1\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
+             '\x11\xb8\xa7\x6b\xad\x9d\xd1\x11\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
              (0x6ba7b811L, 0x9dad, 0x11d1, 0x80, 0xb4, 0x00c04fd430c8L),
              0x6ba7b8119dad11d180b400c04fd430c8L,
              'urn:uuid:6ba7b811-9dad-11d1-80b4-00c04fd430c8',
@@ -70,6 +76,7 @@ class TestUUID(TestCase):
              '{6ba7b812-9dad-11d1-80b4-00c04fd430c8}',
              '6ba7b8129dad11d180b400c04fd430c8',
              '\x6b\xa7\xb8\x12\x9d\xad\x11\xd1\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
+             '\x12\xb8\xa7\x6b\xad\x9d\xd1\x11\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
              (0x6ba7b812L, 0x9dad, 0x11d1, 0x80, 0xb4, 0x00c04fd430c8L),
              0x6ba7b8129dad11d180b400c04fd430c8L,
              'urn:uuid:6ba7b812-9dad-11d1-80b4-00c04fd430c8',
@@ -78,6 +85,7 @@ class TestUUID(TestCase):
              '{6ba7b814-9dad-11d1-80b4-00c04fd430c8}',
              '6ba7b8149dad11d180b400c04fd430c8',
              '\x6b\xa7\xb8\x14\x9d\xad\x11\xd1\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
+             '\x14\xb8\xa7\x6b\xad\x9d\xd1\x11\x80\xb4\x00\xc0\x4f\xd4\x30\xc8',
              (0x6ba7b814L, 0x9dad, 0x11d1, 0x80, 0xb4, 0x00c04fd430c8L),
              0x6ba7b8149dad11d180b400c04fd430c8L,
              'urn:uuid:6ba7b814-9dad-11d1-80b4-00c04fd430c8',
@@ -86,6 +94,7 @@ class TestUUID(TestCase):
              '{7d444840-9dc0-11d1-b245-5ffdce74fad2}',
              '7d4448409dc011d1b2455ffdce74fad2',
              '\x7d\x44\x48\x40\x9d\xc0\x11\xd1\xb2\x45\x5f\xfd\xce\x74\xfa\xd2',
+             '\x40\x48\x44\x7d\xc0\x9d\xd1\x11\xb2\x45\x5f\xfd\xce\x74\xfa\xd2',
              (0x7d444840L, 0x9dc0, 0x11d1, 0xb2, 0x45, 0x5ffdce74fad2L),
              0x7d4448409dc011d1b2455ffdce74fad2L,
              'urn:uuid:7d444840-9dc0-11d1-b245-5ffdce74fad2',
@@ -94,6 +103,7 @@ class TestUUID(TestCase):
              '{e902893a-9d22-3c7e-a7b8-d6e313b71d9f}',
              'e902893a9d223c7ea7b8d6e313b71d9f',
              '\xe9\x02\x89\x3a\x9d\x22\x3c\x7e\xa7\xb8\xd6\xe3\x13\xb7\x1d\x9f',
+             '\x3a\x89\x02\xe9\x22\x9d\x7e\x3c\xa7\xb8\xd6\xe3\x13\xb7\x1d\x9f',
              (0xe902893aL, 0x9d22, 0x3c7e, 0xa7, 0xb8, 0xd6e313b71d9fL),
              0xe902893a9d223c7ea7b8d6e313b71d9fL,
              'urn:uuid:e902893a-9d22-3c7e-a7b8-d6e313b71d9f',
@@ -102,6 +112,7 @@ class TestUUID(TestCase):
              '{eb424026-6f54-4ef8-a4d0-bb658a1fc6cf}',
              'eb4240266f544ef8a4d0bb658a1fc6cf',
              '\xeb\x42\x40\x26\x6f\x54\x4e\xf8\xa4\xd0\xbb\x65\x8a\x1f\xc6\xcf',
+             '\x26\x40\x42\xeb\x54\x6f\xf8\x4e\xa4\xd0\xbb\x65\x8a\x1f\xc6\xcf',
              (0xeb424026L, 0x6f54, 0x4ef8, 0xa4, 0xd0, 0xbb658a1fc6cfL),
              0xeb4240266f544ef8a4d0bb658a1fc6cfL,
              'urn:uuid:eb424026-6f54-4ef8-a4d0-bb658a1fc6cf',
@@ -110,6 +121,7 @@ class TestUUID(TestCase):
              '{f81d4fae-7dec-11d0-a765-00a0c91e6bf6}',
              'f81d4fae7dec11d0a76500a0c91e6bf6',
              '\xf8\x1d\x4f\xae\x7d\xec\x11\xd0\xa7\x65\x00\xa0\xc9\x1e\x6b\xf6',
+             '\xae\x4f\x1d\xf8\xec\x7d\xd0\x11\xa7\x65\x00\xa0\xc9\x1e\x6b\xf6',
              (0xf81d4faeL, 0x7dec, 0x11d0, 0xa7, 0x65, 0x00a0c91e6bf6L),
              0xf81d4fae7dec11d0a76500a0c91e6bf6L,
              'urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6',
@@ -118,6 +130,7 @@ class TestUUID(TestCase):
              '{fffefdfc-fffe-fffe-fffe-fffefdfcfbfa}',
              'fffefdfcfffefffefffefffefdfcfbfa',
              '\xff\xfe\xfd\xfc\xff\xfe\xff\xfe\xff\xfe\xff\xfe\xfd\xfc\xfb\xfa',
+             '\xfc\xfd\xfe\xff\xfe\xff\xfe\xff\xff\xfe\xff\xfe\xfd\xfc\xfb\xfa',
              (0xfffefdfcL, 0xfffe, 0xfffe, 0xff, 0xfe, 0xfffefdfcfbfaL),
              0xfffefdfcfffefffefffefffefdfcfbfaL,
              'urn:uuid:fffefdfc-fffe-fffe-fffe-fffefdfcfbfa',
@@ -126,6 +139,7 @@ class TestUUID(TestCase):
              '{ffffffff-ffff-ffff-ffff-ffffffffffff}',
              'ffffffffffffffffffffffffffffffff',
              '\xff'*16,
+             '\xff'*16,
              (0xffffffffL, 0xffffL, 0xffffL, 0xff, 0xff, 0xffffffffffffL),
              0xffffffffffffffffffffffffffffffffL,
              'urn:uuid:ffffffff-ffff-ffff-ffff-ffffffffffff',
@@ -134,12 +148,14 @@ class TestUUID(TestCase):
             equivalents = []
             # Construct each UUID in several different ways.
             for u in [uuid.UUID(string), uuid.UUID(curly), uuid.UUID(hex),
-                      uuid.UUID(bytes=bytes), uuid.UUID(fields=fields),
-                      uuid.UUID(int=integer), uuid.UUID(urn)]:
+                      uuid.UUID(bytes=bytes), uuid.UUID(bytes_le=bytes_le),
+                      uuid.UUID(fields=fields), uuid.UUID(int=integer),
+                      uuid.UUID(urn)]:
                 # Test all conversions and properties of the UUID object.
                 equal(str(u), string)
                 equal(int(u), integer)
                 equal(u.bytes, bytes)
+                equal(u.bytes_le, bytes_le)
                 equal(u.fields, fields)
                 equal(u.time_low, fields[0])
                 equal(u.time_mid, fields[1])
@@ -189,6 +205,11 @@ class TestUUID(TestCase):
         badvalue(lambda: uuid.UUID(bytes='\0'*15))
         badvalue(lambda: uuid.UUID(bytes='\0'*17))
 
+        # Badly formed bytes_le.
+        badvalue(lambda: uuid.UUID(bytes_le='abc'))
+        badvalue(lambda: uuid.UUID(bytes_le='\0'*15))
+        badvalue(lambda: uuid.UUID(bytes_le='\0'*17))
+
         # Badly formed fields.
         badvalue(lambda: uuid.UUID(fields=(1,)))
         badvalue(lambda: uuid.UUID(fields=(1, 2, 3, 4, 5)))
@@ -221,51 +242,43 @@ class TestUUID(TestCase):
         uuid.UUID(h)
         uuid.UUID(hex=h)
         uuid.UUID(bytes=b)
+        uuid.UUID(bytes_le=b)
         uuid.UUID(fields=f)
         uuid.UUID(int=i)
 
         # Wrong number of arguments (positional).
         badtype(lambda: uuid.UUID())
         badtype(lambda: uuid.UUID(h, b))
-        badtype(lambda: uuid.UUID(h, b, f))
-        badtype(lambda: uuid.UUID(h, b, f, i))
-
-        # Duplicate arguments (named).
-        badtype(lambda: uuid.UUID(hex=h, bytes=b))
-        badtype(lambda: uuid.UUID(hex=h, fields=f))
-        badtype(lambda: uuid.UUID(hex=h, int=i))
-        badtype(lambda: uuid.UUID(bytes=b, fields=f))
-        badtype(lambda: uuid.UUID(bytes=b, int=i))
-        badtype(lambda: uuid.UUID(fields=f, int=i))
-        badtype(lambda: uuid.UUID(hex=h, bytes=b, fields=f))
-        badtype(lambda: uuid.UUID(hex=h, bytes=b, int=i))
-        badtype(lambda: uuid.UUID(hex=h, fields=f, int=i))
-        badtype(lambda: uuid.UUID(bytes=b, int=i, fields=f))
-        badtype(lambda: uuid.UUID(hex=h, bytes=b, int=i, fields=f))
-
-        # Duplicate arguments (positional and named).
-        badtype(lambda: uuid.UUID(h, hex=h))
-        badtype(lambda: uuid.UUID(h, bytes=b))
-        badtype(lambda: uuid.UUID(h, fields=f))
-        badtype(lambda: uuid.UUID(h, int=i))
-        badtype(lambda: uuid.UUID(h, hex=h, bytes=b))
-        badtype(lambda: uuid.UUID(h, hex=h, fields=f))
-        badtype(lambda: uuid.UUID(h, hex=h, int=i))
-        badtype(lambda: uuid.UUID(h, bytes=b, fields=f))
-        badtype(lambda: uuid.UUID(h, bytes=b, int=i))
-        badtype(lambda: uuid.UUID(h, fields=f, int=i))
-        badtype(lambda: uuid.UUID(h, hex=h, bytes=b, fields=f))
-        badtype(lambda: uuid.UUID(h, hex=h, bytes=b, int=i))
-        badtype(lambda: uuid.UUID(h, hex=h, fields=f, int=i))
-        badtype(lambda: uuid.UUID(h, bytes=b, int=i, fields=f))
-        badtype(lambda: uuid.UUID(h, hex=h, bytes=b, int=i, fields=f))
+        badtype(lambda: uuid.UUID(h, b, b))
+        badtype(lambda: uuid.UUID(h, b, b, f))
+        badtype(lambda: uuid.UUID(h, b, b, f, i))
+
+        # Duplicate arguments.
+        for hh in [[], [('hex', h)]]:
+            for bb in [[], [('bytes', b)]]:
+                for bble in [[], [('bytes_le', b)]]:
+                    for ii in [[], [('int', i)]]:
+                        for ff in [[], [('fields', f)]]:
+                            args = dict(hh + bb + bble + ii + ff)
+                            if len(args) != 0:
+                                badtype(lambda: uuid.UUID(h, **args))
+                            if len(args) != 1:
+                                badtype(lambda: uuid.UUID(**args))
 
         # Immutability.
         u = uuid.UUID(h)
         badtype(lambda: setattr(u, 'hex', h))
         badtype(lambda: setattr(u, 'bytes', b))
+        badtype(lambda: setattr(u, 'bytes_le', b))
         badtype(lambda: setattr(u, 'fields', f))
         badtype(lambda: setattr(u, 'int', i))
+        badtype(lambda: setattr(u, 'time_low', 0))
+        badtype(lambda: setattr(u, 'time_mid', 0))
+        badtype(lambda: setattr(u, 'time_hi_version', 0))
+        badtype(lambda: setattr(u, 'time_hi_version', 0))
+        badtype(lambda: setattr(u, 'clock_seq_hi_variant', 0))
+        badtype(lambda: setattr(u, 'clock_seq_low', 0))
+        badtype(lambda: setattr(u, 'node', 0))
 
     def check_node(self, node, source):
         individual_group_bit = (node >> 40L) & 1
@@ -356,11 +369,17 @@ class TestUUID(TestCase):
     def test_uuid1(self):
         equal = self.assertEqual
 
-        # Make sure uuid4() generates UUIDs that are actually version 1.
+        # Make sure uuid1() generates UUIDs that are actually version 1.
         for u in [uuid.uuid1() for i in range(10)]:
             equal(u.variant, uuid.RFC_4122)
             equal(u.version, 1)
 
+        # Make sure the generated UUIDs are actually unique.
+        uuids = {}
+        for u in [uuid.uuid1() for i in range(1000)]:
+            uuids[u] = 1
+        equal(len(uuids.keys()), 1000)
+
         # Make sure the supplied node ID appears in the UUID.
         u = uuid.uuid1(0)
         equal(u.node, 0)
@@ -408,6 +427,12 @@ class TestUUID(TestCase):
             equal(u.variant, uuid.RFC_4122)
             equal(u.version, 4)
 
+        # Make sure the generated UUIDs are actually unique.
+        uuids = {}
+        for u in [uuid.uuid1() for i in range(1000)]:
+            uuids[u] = 1
+        equal(len(uuids.keys()), 1000)
+
     def test_uuid5(self):
         equal = self.assertEqual
 
diff --git a/Lib/uuid.py b/Lib/uuid.py
index a6446a1..684bbeb 100644
--- a/Lib/uuid.py
+++ b/Lib/uuid.py
@@ -45,8 +45,6 @@ Typical usage:
 """
 
 __author__ = 'Ka-Ping Yee <ping@zesty.ca>'
-__date__ = '$Date: 2006/06/12 23:15:40 $'.split()[1].replace('/', '-')
-__version__ = '$Revision: 1.30 $'.split()[1]
 
 RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [
     'reserved for NCS compatibility', 'specified in RFC 4122',
@@ -57,15 +55,21 @@ class UUID(object):
     UUID objects are immutable, hashable, and usable as dictionary keys.
     Converting a UUID to a string with str() yields something in the form
     '12345678-1234-1234-1234-123456789abc'.  The UUID constructor accepts
-    four possible forms: a similar string of hexadecimal digits, or a
-    string of 16 raw bytes as an argument named 'bytes', or a tuple of
-    six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and
-    48-bit values respectively) as an argument named 'fields', or a single
-    128-bit integer as an argument named 'int'.
+    five possible forms: a similar string of hexadecimal digits, or a tuple
+    of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and
+    48-bit values respectively) as an argument named 'fields', or a string
+    of 16 bytes (with all the integer fields in big-endian order) as an
+    argument named 'bytes', or a string of 16 bytes (with the first three
+    fields in little-endian order) as an argument named 'bytes_le', or a
+    single 128-bit integer as an argument named 'int'.
 
     UUIDs have these read-only attributes:
 
-        bytes       the UUID as a 16-byte string
+        bytes       the UUID as a 16-byte string (containing the six
+                    integer fields in big-endian byte order)
+
+        bytes_le    the UUID as a 16-byte string (with time_low, time_mid,
+                    and time_hi_version in little-endian byte order)
 
         fields      a tuple of the six integer fields of the UUID,
                     which are also available as six individual attributes
@@ -94,10 +98,11 @@ class UUID(object):
                     when the variant is RFC_4122)
     """
 
-    def __init__(self, hex=None, bytes=None, fields=None, int=None,
-                       version=None):
+    def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None,
+                       int=None, version=None):
         r"""Create a UUID from either a string of 32 hexadecimal digits,
-        a string of 16 bytes as the 'bytes' argument, a tuple of six
+        a string of 16 bytes as the 'bytes' argument, a string of 16 bytes
+        in little-endian order as the 'bytes_le' argument, a tuple of six
         integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version,
         8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as
         the 'fields' argument, or a single 128-bit integer as the 'int'
@@ -109,23 +114,31 @@ class UUID(object):
         UUID('12345678123456781234567812345678')
         UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
         UUID(bytes='\x12\x34\x56\x78'*4)
+        UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' +
+                      '\x12\x34\x56\x78\x12\x34\x56\x78')
         UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
         UUID(int=0x12345678123456781234567812345678)
 
-        Exactly one of 'hex', 'bytes', 'fields', or 'int' must be given.
-        The 'version' argument is optional; if given, the resulting UUID
-        will have its variant and version number set according to RFC 4122,
-        overriding bits in the given 'hex', 'bytes', 'fields', or 'int'.
+        Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must
+        be given.  The 'version' argument is optional; if given, the resulting
+        UUID will have its variant and version set according to RFC 4122,
+        overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'.
         """
 
-        if [hex, bytes, fields, int].count(None) != 3:
-            raise TypeError('need just one of hex, bytes, fields, or int')
+        if [hex, bytes, bytes_le, fields, int].count(None) != 4:
+            raise TypeError('need one of hex, bytes, bytes_le, fields, or int')
         if hex is not None:
             hex = hex.replace('urn:', '').replace('uuid:', '')
             hex = hex.strip('{}').replace('-', '')
             if len(hex) != 32:
                 raise ValueError('badly formed hexadecimal UUID string')
             int = long(hex, 16)
+        if bytes_le is not None:
+            if len(bytes_le) != 16:
+                raise ValueError('bytes_le is not a 16-char string')
+            bytes = (bytes_le[3] + bytes_le[2] + bytes_le[1] + bytes_le[0] +
+                     bytes_le[5] + bytes_le[4] + bytes_le[7] + bytes_le[6] +
+                     bytes_le[8:])
         if bytes is not None:
             if len(bytes) != 16:
                 raise ValueError('bytes is not a 16-char string')
@@ -194,6 +207,13 @@ class UUID(object):
 
     bytes = property(get_bytes)
 
+    def get_bytes_le(self):
+        bytes = self.bytes
+        return (bytes[3] + bytes[2] + bytes[1] + bytes[0] +
+                bytes[5] + bytes[4] + bytes[7] + bytes[6] + bytes[8:])
+
+    bytes_le = property(get_bytes_le)
+
     def get_fields(self):
         return (self.time_low, self.time_mid, self.time_hi_version,
                 self.clock_seq_hi_variant, self.clock_seq_low, self.node)
@@ -448,6 +468,8 @@ def getnode():
         if _node is not None:
             return _node
 
+_last_timestamp = None
+
 def uuid1(node=None, clock_seq=None):
     """Generate a UUID from a host ID, sequence number, and the current time.
     If 'node' is not given, getnode() is used to obtain the hardware
@@ -460,11 +482,15 @@ def uuid1(node=None, clock_seq=None):
         _uuid_generate_time(_buffer)
         return UUID(bytes=_buffer.raw)
 
+    global _last_timestamp
     import time
     nanoseconds = int(time.time() * 1e9)
     # 0x01b21dd213814000 is the number of 100-ns intervals between the
     # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00.
     timestamp = int(nanoseconds/100) + 0x01b21dd213814000L
+    if timestamp == _last_timestamp:
+        timestamp += 1
+    _last_timestamp = timestamp
     if clock_seq is None:
         import random
         clock_seq = random.randrange(1<<14L) # instead of stable storage