merge

1 files changed, 13 insertions, 8 deletions

diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index b684a9f..c06f4b8 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -16,6 +16,11 @@ except ImportError:
 import io
 from io import (__all__, SEEK_SET, SEEK_CUR, SEEK_END)
 
+valid_seek_flags = {0, 1, 2}  # Hardwired values
+if hasattr(os, 'SEEK_HOLE') :
+    valid_seek_flags.add(os.SEEK_HOLE)
+    valid_seek_flags.add(os.SEEK_DATA)
+
 # open() uses st_blksize whenever we can
 DEFAULT_BUFFER_SIZE = 8 * 1024  # bytes
 
@@ -306,6 +311,7 @@ class IOBase(metaclass=abc.ABCMeta):
         * 0 -- start of stream (the default); offset should be zero or positive
         * 1 -- current stream position; offset may be negative
         * 2 -- end of stream; offset is usually negative
+        Some operating systems / file systems could provide additional values.
 
         Return an int indicating the new absolute position.
         """
@@ -866,7 +872,7 @@ class BytesIO(BufferedIOBase):
         elif whence == 2:
             self._pos = max(0, len(self._buffer) + pos)
         else:
-            raise ValueError("invalid whence value")
+            raise ValueError("unsupported whence value")
         return self._pos
 
     def tell(self):
@@ -1041,7 +1047,7 @@ class BufferedReader(_BufferedIOMixin):
         return _BufferedIOMixin.tell(self) - len(self._read_buf) + self._read_pos
 
     def seek(self, pos, whence=0):
-        if not (0 <= whence <= 2):
+        if whence not in valid_seek_flags:
             raise ValueError("invalid whence value")
         with self._read_lock:
             if whence == 1:
@@ -1138,8 +1144,8 @@ class BufferedWriter(_BufferedIOMixin):
         return _BufferedIOMixin.tell(self) + len(self._write_buf)
 
     def seek(self, pos, whence=0):
-        if not (0 <= whence <= 2):
-            raise ValueError("invalid whence")
+        if whence not in valid_seek_flags:
+            raise ValueError("invalid whence value")
         with self._write_lock:
             self._flush_unlocked()
             return _BufferedIOMixin.seek(self, pos, whence)
@@ -1235,8 +1241,8 @@ class BufferedRandom(BufferedWriter, BufferedReader):
         BufferedWriter.__init__(self, raw, buffer_size, max_buffer_size)
 
     def seek(self, pos, whence=0):
-        if not (0 <= whence <= 2):
-            raise ValueError("invalid whence")
+        if whence not in valid_seek_flags:
+            raise ValueError("invalid whence value")
         self.flush()
         if self._read_buf:
             # Undo read ahead.
@@ -1852,8 +1858,7 @@ class TextIOWrapper(TextIOBase):
                 self._decoder.reset()
             return position
         if whence != 0:
-            raise ValueError("invalid whence (%r, should be 0, 1 or 2)" %
-                             (whence,))
+            raise ValueError("unsupported whence (%r)" % (whence,))
         if cookie < 0:
             raise ValueError("negative seek position %r" % (cookie,))
         self.flush()