--- portage.orig/pym/portage.py	2004-09-11 11:21:38.000000000 +0100
+++ portage/pym/portage.py	2004-09-15 23:38:58.312967072 +0100
@@ -4072,6 +4072,9 @@
 
 	def cpv_exists(self,mycpv):
 		return self.cpvdict.has_key(mycpv)
+
+	def cpv_all(self):
+		return self.cpvdict.keys()
 	
 	def cp_list(self,mycp,use_cache=1):
 		if not self.cpdict.has_key(mycp):
@@ -4418,8 +4421,93 @@
 				myd = ""
 			results.append(myd)
 		return results
+
+	def revdeps(self, mycpv, buildtimedeps=0):
+		"Returns a list of first-level reverse dependencies on cpv."
+
+		myfdb = fakedbapi()
+		for i in self.cpv_all():
+			myfdb.cpv_inject(i)
+		myfdb.cpv_remove(mycpv)
+		myvdb=self
+
+		if buildtimedeps:
+			self.depvars = ["RDEPEND","DEPEND","PDEPEND"]
+		else:
+			self.depvars = ["RDEPEND","PDEPEND"]
 		
+		# Start with some local helper functions. Defined here since they really aren't useful
+		# elsewhere.
+		def potential_revdeps(cpv):
+			mycp=pkgsplit(cpv)[0]
+			#print "'"+cpv+"'"
+			#print myvdb.aux_get(cpv, ["PROVIDE"])
+			myprovide=myvdb.aux_get(cpv, ["PROVIDE"])[0].split()
+			#print cpv,"provides", myprovide
+			
+			myret=[]
+			for x in myvdb.cpv_all():
+				myrawdep=string.join(myvdb.aux_get(x, myvdb.depvars), " ")
+				if string.find(myrawdep, mycp) != -1:
+					myret.append( (x,myrawdep) )
+				for p in myprovide:
+					if string.find(myrawdep, p) != -1:
+						myret.append( (x,myrawdep) )
+			#print "potentials for %s: " % cpv, [ x[0] for x in myret]
+			return myret
+
+		def parse_dep(cpv, dep):
+			""" Returns 1 if cpv and nothing else installed satisfies a requirement of depstring.
+			Takes a paren_ and use_reduced list or single atom for dep. """
+			if type(dep) is list:
+				if len(dep) == 0:
+					return 0
+				elif dep[0] == "||":
+					# Any one of the items is enough to satisfy
+					mylist = dep[1:]
+					cpv_satisfies=0
+					for myatom in mylist:
+						if parse_dep(cpv, myatom):
+							cpv_satisfies=1
+					if not cpv_satisfies:
+						return 0
+					#else:
+					#	print cpv,"matches",dep
+					for myother in myfdb.cpv_all():
+						for myatom in mylist:
+							if parse_dep(cpv, myatom):
+								return 0
+					return 1
+				else:
+					# Not a || list; we handle each atom individually.
+					for myatom in dep:
+						if parse_dep(cpv, myatom):
+							return 1
+					return 0
+			else:
+				# A simple atom. First, check it isn't a !depend...
+				if dep[0] == "!":
+					return 0
+				# If cpv and nothing else matches the dep, return 1
+				if cpv not in myvdb.match(dep):
+					#print cpv,"doesn't match",dep
+					return 0
+				if len(myfdb.match(dep)) == 0:
+					return 1
+				#else:
+				#	print "another matches", dep
+				return 0
 
+		myrevdeps = []
+		for myp,mydep in potential_revdeps(mycpv):
+			myuse = self.aux_get(myp, ["USE"])[0].split()
+			mydep = portage_dep.paren_reduce(mydep)
+			mydep = portage_dep.dep_opconvert(mydep)
+			mydep = portage_dep.use_reduce(mydep,myuse)
+			if parse_dep(mycpv, mydep):
+				myrevdeps.append(myp)
+		return myrevdeps
+			
 class vartree(packagetree):
 	"this tree will scan a var/db/pkg database located at root (passed to init)"
 	def __init__(self,root="/",virtual=None,clone=None,categories=None):