File 0003-UserModel-optimize-filtering-out-duplicate... of Package sddm

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File 0003-UserModel-optimize-filtering-out-duplicate-users-995.patch of Package sddm (Revision acd3959897ad91a8a4d942ee24b0228c)

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From 47f28bb0b903ae1603b8f855e77bbeb79d8e6ace Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: Mon, 19 Mar 2018 19:07:12 -0700
Subject: [PATCH 3/6] UserModel: optimize filtering out duplicate users (#995)

Instead of using naive approach of trying to detect duplicates when
inserting a new user into the list of users, which is O(n^2) complexity,
let's filter them out after the fact, which is much more efficient on
real-world data.

With this change time to load user list in our environment (over 500000
account entries) is reduced from over 1 hour to about 2 seconds.
---
 src/greeter/UserModel.cpp | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/greeter/UserModel.cpp b/src/greeter/UserModel.cpp
index fae5cfa..daf93c5 100644
--- a/src/greeter/UserModel.cpp
+++ b/src/greeter/UserModel.cpp
@@ -75,13 +75,6 @@ namespace SDDM {
             if (mainConfig.Users.HideShells.get().contains(QString::fromLocal8Bit(current_pw->pw_shell)))
                 continue;
 
-            // skip duplicates
-            // Note: getpwent() makes no attempt to suppress duplicate information
-            // if multiple sources are specified in nsswitch.conf(5).
-            if (d->users.cend()
-                != std::find_if(d->users.cbegin(), d->users.cend(), [current_pw](const UserPtr & u) { return u->uid == current_pw->pw_uid; }))
-                continue;
-
             // create user
             UserPtr user { new User() };
             user->name = QString::fromLocal8Bit(current_pw->pw_name);
@@ -107,6 +100,9 @@ namespace SDDM {
 
         // sort users by username
         std::sort(d->users.begin(), d->users.end(), [&](const UserPtr &u1, const UserPtr &u2) { return u1->name < u2->name; });
+        // Remove duplicates in case we have several sources specified
+        // in nsswitch.conf(5).
+        std::unique(d->users.begin(), d->users.end(), [&](const UserPtr &u1, const UserPtr &u2) { return u1->name == u2->name; });
 
         bool avatarsEnabled = mainConfig.Theme.EnableAvatars.get();
         if (avatarsEnabled && mainConfig.Theme.EnableAvatars.isDefault()) {
-- 
2.16.2

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File 0003-UserModel-optimize-filtering-out-duplicate-users-995.patch of Package sddm (Revision acd3959897ad91a8a4d942ee24b0228c)

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