From 881a3de8afdcfdcb51170eca77acd685cb4021e8 Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Mon, 23 Jun 2008 10:00:12 +0000
Subject: [PATCH] Bug #228977 - During dblink._preserve_libs() calls, cache
 results of LinkageMap.findProviders(), LinkageMap.findConsumers(), and
 os.path.realpath() calls in order to improve performance. This makes a huge
 difference in performance for glibc upgrades since glibc provides so many
 libs to check consumerge for.

svn path=/main/trunk/; revision=10764
---
 pym/portage/dbapi/vartree.py | 57 ++++++++++++++++++++++++++++--------
 1 file changed, 45 insertions(+), 12 deletions(-)

diff --git a/pym/portage/dbapi/vartree.py b/pym/portage/dbapi/vartree.py
index f71a20794..835892722 100644
--- a/pym/portage/dbapi/vartree.py
+++ b/pym/portage/dbapi/vartree.py
@@ -201,30 +201,48 @@ class LinkageMap(object):
 	def findProviders(self, obj):
 		if not self._libs:
 			self.rebuild()
+
+		realpath_cache = {}
+		def realpath(p):
+			real_path = realpath_cache.get(p)
+			if real_path is None:
+				real_path = os.path.realpath(p)
+				realpath_cache[p] = real_path
+			return real_path
+
 		rValue = {}
 		if obj not in self._obj_properties:
-			obj = os.path.realpath(obj)
+			obj = realpath(obj)
 			if obj not in self._obj_properties:
 				raise KeyError("%s not in object list" % obj)
 		arch, needed, path, soname = self._obj_properties[obj]
 		path.extend(self._defpath)
-		path = [os.path.realpath(x) for x in path]
+		path = set(realpath(x) for x in path)
 		for x in needed:
 			rValue[x] = set()
 			if x not in self._libs or arch not in self._libs[x]:
 				continue
 			for y in self._libs[x][arch]["providers"]:
-				if x[0] == os.sep and os.path.realpath(x) == os.path.realpath(y):
+				if x[0] == os.sep and realpath(x) == realpath(y):
 					rValue[x].add(y)
-				elif os.path.realpath(os.path.dirname(y)) in path:
+				elif realpath(os.path.dirname(y)) in path:
 					rValue[x].add(y)
 		return rValue
 	
 	def findConsumers(self, obj):
 		if not self._libs:
 			self.rebuild()
+
+		realpath_cache = {}
+		def realpath(p):
+			real_path = realpath_cache.get(p)
+			if real_path is None:
+				real_path = os.path.realpath(p)
+				realpath_cache[p] = real_path
+			return real_path
+
 		if obj not in self._obj_properties:
-			obj = os.path.realpath(obj)
+			obj = realpath(obj)
 			if obj not in self._obj_properties:
 				raise KeyError("%s not in object list" % obj)
 		rValue = set()
@@ -233,10 +251,10 @@ class LinkageMap(object):
 				if obj in self._libs[soname][arch]["providers"]:
 					for x in self._libs[soname][arch]["consumers"]:
 						path = self._obj_properties[x][2]
-						path = [os.path.realpath(y) for y in path+self._defpath]
-						if soname[0] == os.sep and os.path.realpath(soname) == os.path.realpath(obj):
+						path = [realpath(y) for y in path+self._defpath]
+						if soname[0] == os.sep and realpath(soname) == realpath(obj):
 							rValue.add(x)
-						elif os.path.realpath(os.path.dirname(obj)) in path:
+						elif realpath(os.path.dirname(obj)) in path:
 							rValue.add(x)
 		return rValue
 					
@@ -1995,9 +2013,15 @@ class dblink(object):
 			if os.path.islink(x) and os.path.realpath(x) in candidates and x not in mycontents:
 				candidates.add(x)
 
+		provider_cache = {}
+		consumer_cache = {}
+
 		# ignore any libs that are only internally used by the package
 		def has_external_consumers(lib, contents, otherlibs):
-			consumers = linkmap.findConsumers(lib)
+			consumers = consumer_cache.get(lib)
+			if consumers is None:
+				consumers = linkmap.findConsumers(lib)
+				consumer_cache[lib] = consumers
 			contents_without_libs = [x for x in contents if x not in otherlibs]
 			
 			# just used by objects that will be autocleaned
@@ -2024,10 +2048,19 @@ class dblink(object):
 				continue
 			# only preserve the lib if there is no other copy to use for each consumer
 			keep = False
-			for c in linkmap.findConsumers(lib):
+
+			lib_consumers = consumer_cache.get(lib)
+			if lib_consumers is None:
+				lib_consumers = linkmap.findConsumers(lib)
+				consumer_cache[lib] = lib_consumers
+
+			for c in lib_consumers:
 				localkeep = True
-				providers = linkmap.findProviders(c)
-				
+				providers = provider_cache.get(c)
+				if providers is None:
+					providers = linkmap.findProviders(c)
+					provider_cache[c] = providers
+
 				for soname in providers:
 					if lib in providers[soname]:
 						for p in providers[soname]:
-- 
2.26.2