Cursor can now take additional flags when opening the file handle for mapping. Renamed stream to buf, as the first item will be a buffer which uses the cursor underneath. We should add a stream for good measure though

Author: Byron

smmap/stream.py smmap/buf.pysmmap/stream.py renamed to smmap/buf.py

@@ -78,10 +78,12 @@ def assign(self, rhs):
 		self._destroy()
 		self._copy_from(rhs)
 
-	def use_region(self, offset, size, _is_recursive=False):
+	def use_region(self, offset, size, flags = 0, _is_recursive=False):
 		"""Assure we point to a window which allows access to the given offset into the file
 		:param offset: absolute offset in bytes into the file
 		:param size: amount of bytes to map
+		:param flags: additional flags to be given to os.open in case a file handle is initially opened
+			for mapping. Has no effect if a region can actually be reused.
 		:return: this instance - it should be queried for whether it points to a valid memory region.
 			This is not the case if the mapping failed becaues we reached the end of the file
 		:note: The size actually mapped may be smaller than the given size. If that is the case,
@@ -106,6 +108,8 @@ def use_region(self, offset, size, _is_recursive=False):
 				return self
 			# END handle offset too large
 
+			# bisect to find an existing region. The c++ implementation cannot 
+			# do that as it uses a linked list for regions.
 			existing_region = None
 			a = self._rlist
 			lo = 0
@@ -181,7 +185,7 @@ def use_region(self, offset, size, _is_recursive=False):
 					if man._handle_count >= man._max_handle_count:
 						raise Exception
 					#END assert own imposed max file handles
-					self._region = MappedRegion(a.path(), mid.ofs, mid.size)
+					self._region = MappedRegion(a.path(), mid.ofs, mid.size, flags)
 				except Exception:
 					# apparently we are out of system resources or hit a limit
 					# As many more operations are likely to fail in that condition (
@@ -195,7 +199,7 @@ def use_region(self, offset, size, _is_recursive=False):
 						raise
 					#END handle existing recursion
 					man._collect_lru_region(0)
-					return self.use_region(offset, size, True) 
+					return self.use_region(offset, size, flags, True) 
 				#END handle exceptions
 
 				man._handle_count += 1

smmap/mman.py

@@ -1,7 +1,7 @@
 from lib import TestBase
 
-from smmap.stream import *
+from smmap.buf import *
 
-class TestStream(TestBase):
+class TestBuf(TestBase):
 	def test_basics(self):
 		assert False

smmap/test/test_stream.py smmap/test/test_buf.pysmmap/test/test_stream.py renamed to smmap/test/test_buf.py

@@ -93,18 +93,19 @@ class MappedRegion(object):
 	#END handle additional slot
 
 
-	def __init__(self, path, ofs, size):
+	def __init__(self, path, ofs, size, flags = 0):
 		"""Initialize a region, allocate the memory map
 		:param path: path to the file to map
 		:param ofs: **aligned** offset into the file to be mapped 
 		:param size: if size is larger then the file on disk, the whole file will be
 			allocated the the size automatically adjusted
+		:param flags: additional flags to be given when opening the file. 
 		:raise Exception: if no memory can be allocated"""
 		self._b = ofs
 		self._size = 0
 		self._uc = 0
 
-		fd = os.open(path, os.O_RDONLY|getattr(os, 'O_BINARY', 0))
+		fd = os.open(path, os.O_RDONLY|getattr(os, 'O_BINARY', 0)|flags)
 		try:
 			kwargs = dict(access=ACCESS_READ, offset=ofs)
 			corrected_size = size