From 8b86f9b399a8f5af792a04025fdeefc02883f3e5 Mon Sep 17 00:00:00 2001
From: Sebastian Thiel <byronimo@gmail.com>
Date: Wed, 2 Jun 2010 22:40:52 +0200
Subject: initial version of loose object writing and simple cached object
 lookup appears to be working

---
 lib/git/odb/utils.py | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 lib/git/odb/utils.py

(limited to 'lib/git/odb/utils.py')

diff --git a/lib/git/odb/utils.py b/lib/git/odb/utils.py
new file mode 100644
index 00000000..04d3eaba
--- /dev/null
+++ b/lib/git/odb/utils.py
@@ -0,0 +1,78 @@
+import binascii
+import os
+import zlib
+from git.utils import make_sha
+
+__all__ = ('FDSha1Writer', )
+
+#{ Routines
+
+hex_to_bin = binascii.a2b_hex
+bin_to_hex = binascii.b2a_hex
+
+def to_hex_sha(sha):
+	""":return: hexified version  of sha"""
+	if len(sha) == 40:
+		return sha
+	return bin_to_hex(sha)
+	
+def to_bin_sha(sha):
+	if len(sha) == 20:
+		return sha
+	return hex_to_bin(sha)
+
+# os shortcuts
+exists = os.path.exists
+mkdir = os.mkdir
+isdir = os.path.isdir
+rename = os.rename
+dirname = os.path.dirname
+join = os.path.join
+read = os.read
+write = os.write
+close = os.close
+#} END Routines
+
+
+#{ Classes
+
+class FDCompressedSha1Writer(object):
+	"""Digests data written to it, making the sha available, then compress the 
+	data and write it to the file descriptor
+	:note: operates on raw file descriptors
+	:note: for this to work, you have to use the close-method of this instance"""
+	__slots__ = ("fd", "sha1", "zip")
+	
+	# default exception
+	exc = IOError("Failed to write all bytes to filedescriptor")
+	
+	def __init__(self, fd):
+		self.fd = fd
+		self.sha1 = make_sha("")
+		self.zip = zlib.compressobj()
+
+	def write(self, data):
+		""":raise IOError: If not all bytes could be written
+		:return: lenght of incoming data"""
+		self.sha1.update(data)
+		cdata = self.zip.compress(data)
+		bytes_written = write(self.fd, cdata)
+		if bytes_written != len(cdata):
+			raise self.exc
+		return bytes_written
+
+	def sha(self, as_hex = False):
+		""":return: sha so far
+		:param as_hex: if True, sha will be hex-encoded, binary otherwise"""
+		if as_hex:
+			return self.sha1.hexdigest()
+		return self.sha1.digest()
+
+	def close(self):
+		remainder = self.zip.flush()
+		if write(self.fd, remainder) != len(remainder):
+			raise self.exc
+		return close(self.fd)
+
+
+#} END classes 
-- 
cgit v1.2.1