cache: rewrite to support arbitrary validation method

Specifically, the cache can use any portage supported checksum method,
or use the standard mtime approach.  In addition, support controlling
whether or not paths are stored, and generally try to restore some
of the centralization/encapsulation that was in place originally.
(cherry picked from commit bc1aed614fb588f0ade5bcb5d1265a8db0f8d247)

Change-Id: Ic38057e7dbb15063c64a93c99e66e113a7d4c70e

1 files changed, 47 insertions, 39 deletions

diff --git a/pym/portage/dbapi/porttree.py b/pym/portage/dbapi/porttree.py
index dd627e3a7..bffae36bd 100644
--- a/pym/portage/dbapi/porttree.py
+++ b/pym/portage/dbapi/porttree.py
@@ -358,16 +358,16 @@ class portdbapi(dbapi):
 		@returns: A new EbuildMetadataPhase instance, or None if the
 			metadata cache is already valid.
 		"""
-		metadata, st, emtime = self._pull_valid_cache(cpv, ebuild_path, repo_path)
+		metadata, ebuild_hash = self._pull_valid_cache(cpv, ebuild_path, repo_path)
 		if metadata is not None:
 			return None
 
-		process = EbuildMetadataPhase(cpv=cpv, ebuild_path=ebuild_path,
-			ebuild_mtime=emtime, metadata_callback=self._metadata_callback,
+		process = EbuildMetadataPhase(cpv=cpv,
+			ebuild_hash=ebuild_hash, metadata_callback=self._metadata_callback,
 			portdb=self, repo_path=repo_path, settings=self.doebuild_settings)
 		return process
 
-	def _metadata_callback(self, cpv, ebuild_path, repo_path, metadata, mtime):
+	def _metadata_callback(self, cpv, repo_path, metadata, ebuild_hash):
 
 		i = metadata
 		if hasattr(metadata, "items"):
@@ -380,8 +380,17 @@ class portdbapi(dbapi):
 		else:
 			metadata["_eclasses_"] = {}
 
+		try:
+			cache = self.auxdb[repo_path]
+			chf = cache.validation_chf
+			metadata['_%s_' % chf] = getattr(ebuild_hash, chf)
+		except CacheError:
+			# Normally this shouldn't happen, so we'll show
+			# a traceback for debugging purposes.
+			traceback.print_exc()
+			cache = None
+
 		metadata.pop("INHERITED", None)
-		metadata["_mtime_"] = mtime
 
 		eapi = metadata.get("EAPI")
 		if not eapi or not eapi.strip():
@@ -392,20 +401,24 @@ class portdbapi(dbapi):
 				metadata[k] = ""
 			metadata["EAPI"] = "-" + eapi.lstrip("-")
 
-		try:
-			self.auxdb[repo_path][cpv] = metadata
-		except CacheError:
-			# Normally this shouldn't happen, so we'll show
-			# a traceback for debugging purposes.
-			traceback.print_exc()
+		if cache is not None:
+			try:
+				cache[cpv] = metadata
+			except CacheError:
+				# Normally this shouldn't happen, so we'll show
+				# a traceback for debugging purposes.
+				traceback.print_exc()
 		return metadata
 
 	def _pull_valid_cache(self, cpv, ebuild_path, repo_path):
 		try:
 			# Don't use unicode-wrapped os module, for better performance.
-			st = _os.stat(_unicode_encode(ebuild_path,
-				encoding=_encodings['fs'], errors='strict'))
-			emtime = st[stat.ST_MTIME]
+			path = _unicode_encode(ebuild_path,
+				encoding=_encodings['fs'], errors='strict')
+			ebuild_hash = eclass_cache.hashed_path(path)
+			# snag mtime since we use it later, and to trigger stat failure
+			# if it doesn't exist
+			ebuild_hash.mtime
 		except OSError:
 			writemsg(_("!!! aux_get(): ebuild for " \
 				"'%s' does not exist at:\n") % (cpv,), noiselevel=-1)
@@ -422,36 +435,29 @@ class portdbapi(dbapi):
 		auxdbs.append(self.auxdb[repo_path])
 		eclass_db = self._repo_info[repo_path].eclass_db
 
-		doregen = True
 		for auxdb in auxdbs:
 			try:
 				metadata = auxdb[cpv]
 			except KeyError:
-				pass
+				continue
 			except CacheError:
 				if not auxdb.readonly:
 					try:
 						del auxdb[cpv]
-					except KeyError:
-						pass
-					except CacheError:
+					except (KeyError, CacheError):
 						pass
-			else:
-				eapi = metadata.get('EAPI', '').strip()
-				if not eapi:
-					eapi = '0'
-				if not (eapi[:1] == '-' and eapi_is_supported(eapi[1:])) and \
-					emtime == metadata['_mtime_'] and \
-					eclass_db.is_eclass_data_valid(metadata['_eclasses_']):
-					doregen = False
-
-			if not doregen:
+				continue
+			eapi = metadata.get('EAPI', '').strip()
+			if not eapi:
+				eapi = '0'
+			if eapi[:1] == '-' and eapi_is_supported(eapi[1:]):
+				continue
+			if auxdb.validate_entry(metadata, ebuild_hash, eclass_db):
 				break
-
-		if doregen:
+		else:
 			metadata = None
 
-		return (metadata, st, emtime)
+		return (metadata, ebuild_hash)
 
 	def aux_get(self, mycpv, mylist, mytree=None, myrepo=None):
 		"stub code for returning auxilliary db information, such as SLOT, DEPEND, etc."
@@ -492,7 +498,7 @@ class portdbapi(dbapi):
 				_("ebuild not found for '%s'") % mycpv, noiselevel=1)
 			raise KeyError(mycpv)
 
-		mydata, st, emtime = self._pull_valid_cache(mycpv, myebuild, mylocation)
+		mydata, ebuild_hash = self._pull_valid_cache(mycpv, myebuild, mylocation)
 		doregen = mydata is None
 
 		if doregen:
@@ -515,10 +521,10 @@ class portdbapi(dbapi):
 
 			if eapi is not None and not portage.eapi_is_supported(eapi):
 				mydata = self._metadata_callback(
-					mycpv, myebuild, mylocation, {'EAPI':eapi}, emtime)
+					mycpv, ebuild_hash, mylocation, {'EAPI':eapi}, emtime)
 			else:
-				proc = EbuildMetadataPhase(cpv=mycpv, ebuild_path=myebuild,
-					ebuild_mtime=emtime,
+				proc = EbuildMetadataPhase(cpv=mycpv,
+					ebuild_hash=ebuild_hash,
 					metadata_callback=self._metadata_callback, portdb=self,
 					repo_path=mylocation,
 					scheduler=PollScheduler().sched_iface,
@@ -536,15 +542,17 @@ class portdbapi(dbapi):
 		# do we have a origin repository name for the current package
 		mydata["repository"] = self.repositories.get_name_for_location(mylocation)
 		mydata["INHERITED"] = ' '.join(mydata.get("_eclasses_", []))
-		mydata["_mtime_"] = st[stat.ST_MTIME]
+		mydata["_mtime_"] = ebuild_hash.mtime
 
 		eapi = mydata.get("EAPI")
 		if not eapi:
 			eapi = "0"
 			mydata["EAPI"] = eapi
 		if not eapi_is_supported(eapi):
-			for k in set(mydata).difference(("_mtime_", "_eclasses_")):
-				mydata[k] = ""
+			keys = set(mydata)
+			keys.discard("_eclasses_")
+			keys.discard("_mtime_")
+			mydata.update((k, '') for k in keys)
 			mydata["EAPI"] = "-" + eapi.lstrip("-")
 
 		#finally, we look at our internal cache entry and return the requested data.