add python-opendir, an extension module using POSIX opendir semantics

3 files changed, 174 insertions, 0 deletions

diff --git a/packages/python/python-opendir/.mtn2git_empty b/packages/python/python-opendir/.mtn2git_empty
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/packages/python/python-opendir/.mtn2git_empty
diff --git a/packages/python/python-opendir/opendir.pyx b/packages/python/python-opendir/opendir.pyx
new file mode 100644
index 0000000000..1ee81f7382
--- /dev/null
+++ b/packages/python/python-opendir/opendir.pyx
@@ -0,0 +1,149 @@
+##############################################################
+#
+#   opendir.pyx - A class exposing the functionality of
+#   ===========   the opendir() family of C libary functions.
+#
+#   By Gregory Ewing
+#   greg.ewing@canterbury.ac.nz
+#
+#   This software and derivative works created from it
+#   may be used and redistributed without restriction.
+#
+##############################################################
+
+cdef extern from "sys/errno.h":
+	int errno
+
+cdef extern from "stdio.h":
+	char *strerror(int)
+
+cdef extern from "dirent.h":
+	ctypedef struct DIR
+	struct dirent:
+		int d_namlen
+		char d_name[1]
+	DIR *c_opendir "opendir" (char *)
+	int readdir_r(DIR *, dirent *, dirent **)
+	long telldir(DIR *)
+	void seekdir(DIR *, long)
+	void rewinddir(DIR *)
+	int closedir(DIR *)
+	int dirfd(DIR *)
+
+#------------------------------------------------------------------
+
+cdef class opendir:
+	"""opendir(pathname) --> an open directory object
+	
+	Opens a directory and provides incremental access to
+	the filenames it contains. May be used as a file-like
+	object or as an iterator.
+	
+	When used as a file-like object, each call to read()
+	returns one filename, or an empty string when the end
+	of the directory is reached. The close() method should
+	be called when finished with the directory.
+	
+	The close() method should also be called when used as
+	an iterator and iteration is stopped prematurely. If
+	iteration proceeds to completion, the directory is
+	closed automatically."""
+
+	cdef DIR *dir
+	
+	def __cinit__(self, char *path):
+		self.dir = c_opendir(path)
+		if not self.dir:
+			raise IOError(errno, "%s: '%s'" % (strerror(errno), path))
+	
+	def __dealloc__(self):
+		if self.dir:
+			closedir(self.dir)
+
+	def read(self):
+		"""read() --> filename or empty string
+		
+		Returns the next filename from the directory, or an empty
+		string if the end of the directory has been reached."""
+		
+		cdef dirent entry, *result
+		check_open(self)
+		if readdir_r(self.dir, &entry, &result) < 0:
+			raise IOError(errno)
+		if result:
+			return entry.d_name
+		else:
+			return ""
+	
+	def tell(self):
+		"""tell() --> position
+		
+		Returns a value representing the current position in the
+		directory, suitable for passing to tell(). Only valid for
+		this directory object as long as it remains open."""
+		
+		check_open(self)
+		return telldir(self.dir)
+
+	def seek(self, long pos):
+		"""seek(position)
+		
+		Returns the directory to the specified position, which
+		should be a value previously returned by tell()."""
+		
+		check_open(self)
+		seekdir(self.dir, pos)
+	
+	def rewind(self):
+		"""rewind()
+		
+		Resets the position to the beginning of the directory."""
+		
+		check_open(self)
+		rewinddir(self.dir)
+	
+	def close(self):
+		"""close()
+		
+		Closes the directory and frees the underlying file descriptor."""
+		
+		if self.dir:
+			if closedir(self.dir) < 0:
+				raise IOError(errno)
+			self.dir = NULL
+
+#  MaxOSX doesn't seem to have dirfd, despite what the
+#  man page says. :-(
+#
+#	def fileno(self):
+#		"""fileno() --> file descriptor
+#		
+#		Returns the file descriptor associated with the open directory."""
+#
+#		check_open(self)
+#		return dirfd(self.dir)
+
+	def __iter__(self):
+		return self
+	
+	def __next__(self):
+		"""next() --> filename
+		
+		Returns the next filename from the directory. If the end of the
+		directory has been reached, closes the directory and raises
+		StopIteration."""
+
+		if self.dir:
+			result = self.read()
+			if result:
+				return result
+			self.close()
+		raise StopIteration
+
+#------------------------------------------------------------------
+
+cdef int check_open(opendir d) except -1:
+	if not d.dir:
+		raise ValueError("Directory is closed")
+	return 0
+
diff --git a/packages/python/python-opendir/setup.py b/packages/python/python-opendir/setup.py
new file mode 100644
index 0000000000..d76b22c95a
--- /dev/null
+++ b/packages/python/python-opendir/setup.py
@@ -0,0 +1,25 @@
+from distutils.core import setup
+from distutils.extension import Extension
+from Cython.Distutils import build_ext
+
+setup(
+  name = 'opendir',
+  version = '0.0.1',
+  author = 'Gregory Ewing',
+  author_email = 'greg ewing at canterbury ac nz',
+  maintainer = 'Johannes "josch" Schauer',
+  maintainer_email = 'j schauer at email de',
+  description = 'Implements POSIX opendir',
+  classifiers = [
+    'Development Status :: 4 - Beta',
+    'Intended Audience :: Developers',
+    'Operating System :: POSIX',
+    'Programming Language :: Pyrex',
+    'Topic :: Software Development :: Libraries :: Python Modules',
+    'Topic :: System :: Filesystems'
+  ],
+  ext_modules=[ 
+    Extension("opendir", ["opendir.pyx"]),
+    ],
+  cmdclass = {'build_ext': build_ext}
+)