[gentoo-portage-dev] Re: [PATCH] emerge --search: use description index

[Zac Medico]

This updated patch changes the index format to use spaces instead of
commas, for readability. This example given in man/portage.5:

sys-apps/sed 4.2 4.2.1 4.2.1-r1 4.2.2: Super-useful stream editor
sys-apps/usleep 0.1: A wrapper for usleep

Hopefully that's easier on the eyes (thanks to Michał Górny for the
suggestion).

Also, Michał has brought it to my attention that git will send the
whole file instead of the delta, unless an expensive `git repack`
operation is performed. Maybe it's possible to repack the user.git
each time the index is generated? Currently, the master rsync mirror
runs egencache every 30 minutes. If user.git syncs at the same
interval, it would need to be repacked at the same interval.

Anyway, it would be nice to merge this patch, even if we don't have
the resources now to generate the index for gentoo on the server side.
We could follow up this patch later with a post emerge --sync hook
for client-side index generation.


From 5192579f79da36f5a1ce5f3651c26ccb235cca28 Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@g.o>
Date: Fri, 17 Oct 2014 17:38:59 -0700
Subject: [PATCH] emerge --search: use description index

This adds an egencache --update-pkg-desc-index action which generates
a plain-text index of package names, versions, and descriptions. The
index can then be used to optimize emerge --search / --searchdesc
actions. If the package description index is missing from a particular
repository, then all metadata for that repository is obtained using the
normal pordbapi.aux_get method.

Searching of installed packages is optimized to take advantage of
vardbdbapi._aux_cache, which is backed by vdb_metadata.pickle.
See the IndexedVardb docstring for some more details.

For users that would like to modify ebuilds in a repository without
running egencache afterwards, the new emerge --search-index < y | n >
option can be used to get non-indexed search. Alternatively, the user
could simply remove the stale index file, in order to disable the
search index for a particular repository.

X-Gentoo-Bug: 525718
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=525718
---
 bin/egencache          |  39 +++++++++-
 man/egencache.1        |   4 +
 man/emerge.1           |   8 ++
 man/portage.5          |  12 +++
 pym/_emerge/actions.py |   3 +-
 pym/_emerge/main.py    |   5 ++
 pym/_emerge/search.py  | 207 +++++++++++++++++++++++++++++++++++++++++++++----
 7 files changed, 261 insertions(+), 17 deletions(-)

diff --git a/bin/egencache b/bin/egencache
index e366058..95cb1ad 100755
--- a/bin/egencache
+++ b/bin/egencache
@@ -57,7 +57,7 @@ from portage.util._async.run_main_scheduler import run_main_scheduler
 from portage.util._eventloop.global_event_loop import global_event_loop
 from portage import cpv_getkey
 from portage.dep import Atom, isjustname
-from portage.versions import pkgsplit, vercmp
+from portage.versions import pkgsplit, vercmp, _pkg_str
 
 try:
 	from xml.etree import ElementTree
@@ -91,6 +91,9 @@ def parse_args(args):
 	actions.add_argument("--update-changelogs",
 		action="store_true",
 		help="update the ChangeLog files from SCM logs")
+	actions.add_argument("--update-pkg-desc-index",
+		action="store_true",
+		help="update package description index")
 	actions.add_argument("--update-manifests",
 		action="store_true",
 		help="update manifests")
@@ -451,6 +454,31 @@ class GenCache(object):
 		if hasattr(trg_cache, '_prune_empty_dirs'):
 			trg_cache._prune_empty_dirs()
 
+class GenPkgDescIndex(object):
+	def __init__(self, portdb, output_file):
+		self.returncode = os.EX_OK
+		self._portdb = portdb
+		self._output_file = output_file
+
+	def run(self):
+
+		portage.util.ensure_dirs(os.path.dirname(self._output_file))
+		f = portage.util.atomic_ofstream(self._output_file,
+			encoding=_encodings["repo.content"])
+
+		portdb = self._portdb
+		for cp in portdb.cp_all():
+			pkgs = portdb.cp_list(cp)
+			if not pkgs:
+				continue
+			desc, = portdb.aux_get(pkgs[-1], ["DESCRIPTION"])
+
+			f.write("%s %s: %s\n" % (cp,
+				" ".join(_pkg_str(cpv).version
+				for cpv in pkgs), desc))
+
+		f.close()
+
 class GenUseLocalDesc(object):
 	def __init__(self, portdb, output=None,
 			preserve_comments=False):
@@ -893,7 +921,8 @@ def egencache_main(args):
 			local_config=False, env=env)
 
 	if not (options.update or options.update_use_local_desc or
-			options.update_changelogs or options.update_manifests):
+			options.update_changelogs or options.update_manifests or
+			options.update_pkg_desc_index):
 		parser.error('No action specified')
 		return 1
 
@@ -1057,6 +1086,12 @@ def egencache_main(args):
 		else:
 			ret.append(scheduler.returncode)
 
+	if options.update_pkg_desc_index:
+		gen_index = GenPkgDescIndex(portdb, os.path.join(
+			repo_config.location, "metadata", "pkg_desc_index"))
+		gen_index.run()
+		ret.append(gen_index.returncode)
+
 	if options.update_use_local_desc:
 		gen_desc = GenUseLocalDesc(portdb,
 			output=options.uld_output,
diff --git a/man/egencache.1 b/man/egencache.1
index f71feb3..3a3197f 100644
--- a/man/egencache.1
+++ b/man/egencache.1
@@ -19,6 +19,10 @@ for the details on package atom syntax.
 .BR "\-\-update\-changelogs"
 Update the ChangeLog files from SCM logs (supported only in git repos).
 .TP
+.BR "\-\-update\-pkg\-desc\-index"
+Update the package description index which is located at
+\fImetadata/pkg_desc_index\fR in the repository.
+.TP
 .BR "\-\-update\-use\-local\-desc"
 Update the \fIprofiles/use.local.desc\fR file from metadata.xml.
 .TP
diff --git a/man/emerge.1 b/man/emerge.1
index 2264b58..efd5d41 100644
--- a/man/emerge.1
+++ b/man/emerge.1
@@ -790,6 +790,14 @@ If ebuilds using EAPIs which \fIdo not\fR support \fBHDEPEND\fR are built in
 the same \fBemerge\fR run as those using EAPIs which \fIdo\fR support
 \fBHDEPEND\fR, this option affects only the former.
 .TP
+.BR "\-\-search\-index < y | n >"
+Enable or disable indexed search for search actions. This option is
+enabled by default. The search index needs to be regenerated by
+\fBegencache\fR(1) after changes are made to a repository (see the
+\fB\-\-update\-pkg\-desc\-index\fR action). This setting can be added
+to \fBEMERGE_DEFAULT_OPTS\fR (see \fBmake.conf\fR(5)) and later
+overridden via the command line.
+.TP
 .BR "\-\-select [ y | n ] (\-w short option)"
 Add specified packages to the world set (inverse of
 \fB\-\-oneshot\fR). This is useful if you want to
diff --git a/man/portage.5 b/man/portage.5
index e399f0f..bf9457c 100644
--- a/man/portage.5
+++ b/man/portage.5
@@ -75,6 +75,7 @@ user\-defined package sets
 .BR /usr/portage/metadata/
 .nf
 layout.conf
+pkg_desc_index
 .fi
 .TP
 .BR /usr/portage/profiles/
@@ -1110,6 +1111,17 @@ cache\-formats = md5-dict pms
 profile\-formats = portage-2
 .fi
 .RE
+.TP
+.BR pkg_desc_index
+This is an index of package names, versions, and descriptions which
+may be generated by \fBegencache\fR(1) in order to optimize
+\fBemerge\fR(1) search actions.
+
+.I Example:
+.nf
+sys-apps/sed 4.2 4.2.1 4.2.1-r1 4.2.2: Super-useful stream editor
+sys-apps/usleep 0.1: A wrapper for usleep
+.fi
 .RE
 .TP
 .BR /usr/portage/profiles/
diff --git a/pym/_emerge/actions.py b/pym/_emerge/actions.py
index 4e8b83b..a81212c 100644
--- a/pym/_emerge/actions.py
+++ b/pym/_emerge/actions.py
@@ -2015,7 +2015,8 @@ def action_search(root_config, myopts, myfiles, spinner):
 		searchinstance = search(root_config,
 			spinner, "--searchdesc" in myopts,
 			"--quiet" not in myopts, "--usepkg" in myopts,
-			"--usepkgonly" in myopts)
+			"--usepkgonly" in myopts,
+			search_index = myopts.get("--search-index", "y") != "n")
 		for mysearch in myfiles:
 			try:
 				searchinstance.execute(mysearch)
diff --git a/pym/_emerge/main.py b/pym/_emerge/main.py
index 3883f72..d403b36 100644
--- a/pym/_emerge/main.py
+++ b/pym/_emerge/main.py
@@ -616,6 +616,11 @@ def parse_opts(tmpcmdline, silent=False):
 			"choices" :("True", "rdeps")
 		},
 
+		"--search-index": {
+			"help": "Enable or disable indexed search (enabled by default)",
+			"choices": y_or_n
+		},
+
 		"--select": {
 			"shortopt" : "-w",
 			"help"    : "add specified packages to the world set " + \
diff --git a/pym/_emerge/search.py b/pym/_emerge/search.py
index 4b0fd9f..37fee20 100644
--- a/pym/_emerge/search.py
+++ b/pym/_emerge/search.py
@@ -3,13 +3,17 @@
 
 from __future__ import print_function
 
+import io
 import re
 import portage
-from portage import os
+from portage import os, _encodings
 from portage.dbapi.porttree import _parse_uri_map
+from portage.dep import Atom
+from portage.exception import InvalidAtom, InvalidData
 from portage.localization import localized_size
 from portage.output import  bold, bold as white, darkgreen, green, red
 from portage.util import writemsg_stdout
+from portage.versions import _pkg_str
 
 from _emerge.Package import Package
 
@@ -25,12 +29,11 @@ class search(object):
 	# public interface
 	#
 	def __init__(self, root_config, spinner, searchdesc,
-		verbose, usepkg, usepkgonly):
+		verbose, usepkg, usepkgonly, search_index = True):
 		"""Searches the available and installed packages for the supplied search key.
 		The list of available and installed packages is created at object instantiation.
 		This makes successive searches faster."""
 		self.settings = root_config.settings
-		self.vartree = root_config.trees["vartree"]
 		self.spinner = spinner
 		self.verbose = verbose
 		self.searchdesc = searchdesc
@@ -45,6 +48,10 @@ class search(object):
 		bindb = root_config.trees["bintree"].dbapi
 		vardb = root_config.trees["vartree"].dbapi
 
+		if search_index:
+			portdb = IndexedPortdb(portdb)
+			vardb = IndexedVardb(vardb)
+
 		if not usepkgonly and portdb._have_root_eclass_dir:
 			self._dbs.append(portdb)
 
@@ -53,6 +60,7 @@ class search(object):
 
 		self._dbs.append(vardb)
 		self._portdb = portdb
+		self._vardb = vardb
 
 	def _spinner_update(self):
 		if self.spinner:
@@ -97,7 +105,7 @@ class search(object):
 		return {}
 
 	def _visible(self, db, cpv, metadata):
-		installed = db is self.vartree.dbapi
+		installed = db is self._vardb
 		built = installed or db is not self._portdb
 		pkg_type = "ebuild"
 		if installed:
@@ -208,6 +216,22 @@ class search(object):
 					masked=1
 				self.matches["pkg"].append([package,masked])
 			elif self.searchdesc: # DESCRIPTION searching
+				# Check for DESCRIPTION match first, so that we can skip
+				# the expensive visiblity check if it doesn't match.
+				full_package = self._xmatch("match-all", package)
+				if not full_package:
+					continue
+				full_package = full_package[-1]
+				try:
+					full_desc = self._aux_get(
+						full_package, ["DESCRIPTION"])[0]
+				except KeyError:
+					portage.writemsg(
+						"emerge: search: aux_get() failed, skipping\n",
+						noiselevel=-1)
+					continue
+				if not self.searchre.search(full_desc):
+					continue
 				full_package = self._xmatch("bestmatch-visible", package)
 				if not full_package:
 					#no match found; we don't want to query description
@@ -217,14 +241,8 @@ class search(object):
 						continue
 					else:
 						masked=1
-				try:
-					full_desc = self._aux_get(
-						full_package, ["DESCRIPTION"])[0]
-				except KeyError:
-					print("emerge: search: aux_get() failed, skipping")
-					continue
-				if self.searchre.search(full_desc):
-					self.matches["desc"].append([full_package,masked])
+
+				self.matches["desc"].append((full_package, masked))
 
 		self.sdict = self.setconfig.getSets()
 		for setname in self.sdict:
@@ -262,7 +280,7 @@ class search(object):
 			bold(self.searchkey) + " ]\n")
 		msg.append("[ Applications found : " + \
 			bold(str(self.mlen)) + " ]\n\n")
-		vardb = self.vartree.dbapi
+		vardb = self._vardb
 		metadata_keys = set(Package.metadata_keys)
 		metadata_keys.update(["DESCRIPTION", "HOMEPAGE", "LICENSE", "SRC_URI"])
 		metadata_keys = tuple(metadata_keys)
@@ -372,7 +390,11 @@ class search(object):
 	# private interface
 	#
 	def getInstallationStatus(self,package):
-		installed_package = self.vartree.dep_bestmatch(package)
+		installed_package = self._vardb.match(package)
+		if installed_package:
+			installed_package = installed_package[-1]
+		else:
+			installed_package = ""
 		result = ""
 		version = self.getVersion(installed_package,search.VERSION_RELEASE)
 		if len(version) > 0:
@@ -392,3 +414,160 @@ class search(object):
 			result = ""
 		return result
 
+
+class IndexedPortdb(object):
+	"""
+	A portdbapi interface that uses a package description index to
+	improve performance. If the description index is missing for a
+	particular repository, then all metadata for that repository is
+	obtained using the normal pordbapi.aux_get method.
+	"""
+	def __init__(self, portdb):
+		self._portdb = portdb
+		self.cpv_exists = portdb.cpv_exists
+		self.getFetchMap = portdb.getFetchMap
+		self.findname = portdb.findname
+		self._aux_cache_keys = portdb._aux_cache_keys
+		self._have_root_eclass_dir = portdb._have_root_eclass_dir
+		self._cpv_sort_ascending = portdb._cpv_sort_ascending
+		self._desc_cache = None
+		self._cp_map = None
+
+	def _init_index(self):
+		cp_map = {}
+		desc_cache = {}
+		for repo_path in self._portdb.porttrees:
+			outside_repo = os.path.join(self._portdb.depcachedir,
+				repo_path.lstrip(os.sep))
+			for parent_dir in (repo_path, outside_repo):
+				file_path = os.path.join(parent_dir,
+					"metadata", "pkg_desc_index")
+
+				try:
+					with io.open(file_path,
+						encoding=_encodings["repo.content"]) as f:
+						for line in f:
+							try:
+								pkgs, desc = line.split(":", 1)
+							except ValueError:
+								continue
+							desc = desc.strip()
+							try:
+								cp, pkgs = pkgs.split(" ", 1)
+							except ValueError:
+								continue
+							if not cp:
+								continue
+							try:
+								atom = Atom(cp)
+							except InvalidAtom:
+								continue
+							if cp != atom.cp:
+								continue
+							cp_list = cp_map.get(cp)
+							if cp_list is None:
+								cp_list = []
+								cp_map[cp] = cp_list
+							for ver in pkgs.split():
+								try:
+									cpv = _pkg_str(cp + "-" + ver)
+								except InvalidData:
+									pass
+								else:
+									cp_list.append(cpv)
+									desc_cache[cpv] = desc
+				except IOError:
+					pass
+				else:
+					break
+			else:
+				# No descriptions index was found, so populate
+				# cp_map the slow way.
+				for cp in self._portdb.cp_all(trees=[repo_path]):
+					cp_list = cp_map.get(cp)
+					if cp_list is None:
+						cp_list = []
+						cp_map[cp] = cp_list
+					for cpv in self._portdb.cp_list(cp, mytree=repo_path):
+						if cpv not in cp_list:
+							cp_list.append(_pkg_str(cpv))
+
+		self._desc_cache = desc_cache
+		self._cp_map = cp_map
+
+	def cp_all(self):
+		if self._cp_map is None:
+			self._init_index()
+		return list(self._cp_map)
+
+	def match(self, atom):
+		if not isinstance(atom, Atom):
+			atom = Atom(atom)
+		cp_list = self._cp_map.get(atom.cp)
+		if cp_list is None:
+			return []
+		self._portdb._cpv_sort_ascending(cp_list)
+		return portage.match_from_list(atom, cp_list)
+
+	def aux_get(self, cpv, attrs, myrepo = None):
+		if len(attrs) == 1 and attrs[0] == "DESCRIPTION":
+			try:
+				return [self._desc_cache[cpv]]
+			except KeyError:
+				pass
+		return self._portdb.aux_get(cpv, attrs)
+
+
+class IndexedVardb(object):
+	"""
+	A vardbapi interface that sacrifices validation in order to
+	improve performance. It takes advantage of vardbdbapi._aux_cache,
+	which is backed by vdb_metadata.pickle. Since _aux_cache is
+	not updated for every single merge/unmerge (see
+	_aux_cache_threshold), the list of packages is obtained directly
+	from the real vardbapi instance. If a package is missing from
+	_aux_cache, then its metadata is obtained using the normal
+	(validated) vardbapi.aux_get method.
+	"""
+	def __init__(self, vardb):
+		self._vardb = vardb
+		self._aux_cache_keys = vardb._aux_cache_keys
+		self._cpv_sort_ascending = vardb._cpv_sort_ascending
+		self._cp_map = {}
+		self.cpv_exists = vardb.cpv_exists
+
+	def cp_all(self):
+		if self._cp_map:
+			return list(self._cp_map)
+		cp_map = self._cp_map
+		for cpv in self._vardb.cpv_all():
+			cp = portage.cpv_getkey(cpv)
+			if cp is not None:
+				cp_list = cp_map.get(cp)
+				if cp_list is None:
+					cp_list = []
+					cp_map[cp] = cp_list
+				cp_list.append(_pkg_str(cpv))
+		return list(cp_map)
+
+	def match(self, atom):
+		if not isinstance(atom, Atom):
+			atom = Atom(atom)
+		cp_list = self._cp_map.get(atom.cp)
+		if cp_list is None:
+			return []
+		self._vardb._cpv_sort_ascending(cp_list)
+		return portage.match_from_list(atom, cp_list)
+
+	def aux_get(self, cpv, attrs, myrepo = None):
+		pkg_data = self._vardb._aux_cache["packages"].get(cpv)
+		if not isinstance(pkg_data, tuple) or \
+			len(pkg_data) != 2 or \
+			not isinstance(pkg_data[1], dict):
+			pkg_data = None
+		if pkg_data is None:
+			# It may be missing from _aux_cache due to
+			# _aux_cache_threshold.
+			return self._vardb.aux_get(cpv, attrs)
+		metadata = pkg_data[1]
+		return [metadata.get(k, "") for k in attrs]
-- 
2.0.4