From: Zac Medico <zmedico@gentoo.org>
Date: Sun, 1 Mar 2009 20:39:41 +0000 (-0000)
Subject: Thanks to Petteri Räty <betelgeuse@gentoo.org> for this new cache module which
X-Git-Tag: v2.2_rc24~78
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=0fd611deddcec58a2bab9b2d1351d05293cb84a5;p=portage.git

Thanks to Petteri Räty <betelgeuse@gentoo.org> for this new cache module which
uses extended attributes (via pyxattr) to attach metadata cache directly to
the ebuild files themselves.

svn path=/main/trunk/; revision=12737
---

diff --git a/pym/portage/cache/ebuild_xattr.py b/pym/portage/cache/ebuild_xattr.py
new file mode 100644
index 000000000..83ed8a783
--- /dev/null
+++ b/pym/portage/cache/ebuild_xattr.py
@@ -0,0 +1,163 @@
+# -*- coding: UTF8 -*-
+# Copyright: 2009 Gentoo Foundation
+# Author(s): Petteri Räty (betelgeuse@gentoo.org)
+# License: GPL2
+# $Id$
+
+__all__ = ['database']
+
+from portage.cache import fs_template
+from portage.versions import catsplit
+from portage import cpv_getkey
+from portage.util import writemsg
+import os
+import xattr
+from errno import ENODATA,ENOSPC,E2BIG
+
+class NoValueException(Exception):
+	pass
+
+class database(fs_template.FsBased):
+
+	autocommits = True
+
+	def __init__(self, *args, **config):
+		super(database,self).__init__(*args, **config)
+		self.portdir = self.label
+		self.ns = xattr.NS_USER + '.gentoo.cache'
+		self.keys = set(self._known_keys)
+		self.keys.add('_mtime_')
+		self.keys.add('_eclasses_')
+		# xattrs have an upper length
+		self.max_len = self.__get_max()
+
+	def __get_max(self):
+		path = os.path.join(self.portdir,'profiles/repo_name')
+		try:
+			return int(self.__get(path,'value_max_len'))
+		except NoValueException,e:
+			max = self.__calc_max(path)
+			self.__set(path,'value_max_len',str(max))
+			return max
+
+	def __calc_max(self,path):
+		""" Find out max attribute length supported by the file system """
+
+		hundred = ''
+		for i in range(100):
+			hundred+='a'
+
+		s=hundred
+
+		# Could use finally but needs python 2.5 then
+		try:
+			while True:
+				self.__set(path,'test_max',s)
+				s+=hundred
+		except IOError,e:
+			# ext based give wrong errno
+			# http://bugzilla.kernel.org/show_bug.cgi?id=12793
+			if e.errno in (E2BIG,ENOSPC):
+				result = len(s)-100
+			else:
+				raise e
+
+		try:
+			self.__remove(path,'test_max')
+		except IOError,e:
+			if e.errno is not ENODATA:
+				raise e
+
+		return result
+
+	def __get_path(self,cpv):
+		cat,pn = catsplit(cpv_getkey(cpv))
+		return os.path.join(self.portdir,cat,pn,os.path.basename(cpv) + ".ebuild")
+
+	def __has_cache(self,path):
+		try:
+			self.__get(path,'_mtime_')
+		except NoValueException,e:
+			return False
+
+		return True
+
+	def __get(self,path,key,default=None):
+		try:
+			return xattr.get(path,key,namespace=self.ns)
+		except IOError,e:
+			if not default is None and ENODATA == e.errno:
+				return default
+			else:
+				raise NoValueException()
+
+	def __remove(self,path,key):
+		xattr.remove(path,key,namespace=self.ns)
+
+	def __set(self,path,key,value):
+		xattr.set(path,key,value,namespace=self.ns)
+
+	def _getitem(self, cpv):
+		values = {}
+		path = self.__get_path(cpv)
+		all = {}
+		for tuple in xattr.get_all(path,namespace=self.ns):
+			key,value = tuple
+			all[key] = value
+
+		if not '_mtime_' in all:
+			raise KeyError(cpv)
+
+		# We default to '' like other caches
+		for key in self.keys:
+			attr_value = all.get(key,'1:')
+			parts,sep,value = attr_value.partition(':')
+			parts = int(parts)
+			if parts > 1:
+				for i in range(1,parts):
+					value += all.get(key+str(i))
+			values[key] = value
+
+		return values
+
+	def _setitem(self, cpv, values):
+		path = self.__get_path(cpv)
+		max = self.max_len
+		for key,value in values.iteritems():
+			# mtime comes in as long so need to convert to strings
+			s = str(value)
+			# We need to split long values
+			value_len = len(s)
+			parts = 0
+			if value_len > max:
+				# Find out how many parts we need
+				parts = value_len/max
+				if value_len % max > 0:
+					parts += 1
+
+				# Only the first entry carries the number of parts
+				self.__set(path,key,'%s:%s'%(parts,s[0:max]))
+
+				# Write out the rest
+				for i in range(1,parts):
+					start = i * max
+					val = s[start:start+max]
+					self.__set(path,key+str(i),val)
+			else:
+				self.__set(path,key,"%s:%s"%(1,s))
+
+	def _delitem(self, cpv):
+		pass # Will be gone with the ebuild
+
+	def __contains__(self, cpv):
+		return os.path.exists(self.__get_path(cpv))
+
+	def __iter__(self):
+		for root,dirs,files in os.walk(self.portdir):
+			for file in files:
+				if file[-7:] == '.ebuild':
+					cat = os.path.basename(os.path.dirname(root))
+					pn_pv = file[:-7]
+					path = os.path.join(root,file)
+					if self.__has_cache(path):
+						yield "%s/%s/%s" % (cat,os.path.basename(root),file[:-7])