[PATCH 2/3] sqlite: add lazy connection init

Signed-off-by: Zac Medico <[email protected]>
---
 lib/portage/cache/sqlite.py | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/lib/portage/cache/sqlite.py b/lib/portage/cache/sqlite.py
index 55ae8f0e5..0395dd516 100644
--- a/lib/portage/cache/sqlite.py
+++ b/lib/portage/cache/sqlite.py
@@ -1,6 +1,7 @@
 # Copyright 1999-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
+import collections
 import re
 
 from portage.cache import fs_template
@@ -23,6 +24,9 @@ class database(fs_template.FsBased):
 	# equation: cache_bytes = page_bytes * page_count
 	cache_bytes = 1024 * 1024 * 10
 
+	_connection_info_entry = collections.namedtuple('_connection_info_entry',
+		('connection', 'cursor'))
+
 	def __init__(self, *args, **config):
 		super(database, self).__init__(*args, **config)
 		self._import_sqlite()
@@ -44,8 +48,8 @@ class database(fs_template.FsBased):
 		# Set longer timeout for throwing a "database is locked" exception.
 		# Default timeout in sqlite3 module is 5.0 seconds.
 		config.setdefault("timeout", 15)
-		self._db_init_connection(config)
-		self._db_init_structures()
+		self._config = config
+		self._db_connection_info = None
 
 	def _import_sqlite(self):
 		# sqlite3 is optional with >=python-2.5
@@ -65,7 +69,20 @@ class database(fs_template.FsBased):
 			s = str(s)
 		return "'%s'" % s.replace("'", "''")
 
-	def _db_init_connection(self, config):
+	@property
+	def _db_cursor(self):
+		if self._db_connection_info is None:
+			self._db_init_connection()
+		return self._db_connection_info.cursor
+
+	@property
+	def _db_connection(self):
+		if self._db_connection_info is None:
+			self._db_init_connection()
+		return self._db_connection_info.connection
+
+	def _db_init_connection(self):
+		config = self._config
 		self._dbpath = self.location + ".sqlite"
 		#if os.path.exists(self._dbpath):
 		#	os.unlink(self._dbpath)
@@ -74,14 +91,16 @@ class database(fs_template.FsBased):
 		try:
 			if not self.readonly:
 				self._ensure_dirs()
-			self._db_connection = self._db_module.connect(
+			connection = self._db_module.connect(
 				database=_unicode_decode(self._dbpath), **connection_kwargs)
-			self._db_cursor = self._db_connection.cursor()
+			cursor = connection.cursor()
+			self._db_connection_info = self._connection_info_entry(connection, cursor)
 			self._db_cursor.execute("PRAGMA encoding = %s" % self._db_escape_string("UTF-8"))
 			if not self.readonly and not self._ensure_access(self._dbpath):
 				raise cache_errors.InitializationError(self.__class__, "can't ensure perms on %s" % self._dbpath)
 			self._db_init_cache_size(config["cache_bytes"])
 			self._db_init_synchronous(config["synchronous"])
+			self._db_init_structures()
 		except self._db_error as e:
 			raise cache_errors.InitializationError(self.__class__, e)
 
-- 
2.25.3