C++17 fixes

`std::random_shuffle` and `std::mem_fun` have been removed.

Author: hatstand

src/covers/musicbrainzcoverprovider.cpp

@@ -21,13 +21,10 @@
 #include <QUrlQuery>
 #include <QXmlStreamReader>
 #include <algorithm>
-#include <functional>
 
 #include "core/closure.h"
 #include "core/network.h"
 
-using std::mem_fun;
-
 namespace {
 
 static const char* kReleaseSearchUrl = "https://musicbrainz.org/ws/2/release/";
@@ -88,8 +85,9 @@ void MusicbrainzCoverProvider::ReleaseSearchFinished(QNetworkReply* reply,
 
 void MusicbrainzCoverProvider::ImageCheckFinished(int id) {
   QList<QNetworkReply*> replies = image_checks_.values(id);
-  int finished_count = std::count_if(replies.constBegin(), replies.constEnd(),
-                                     mem_fun(&QNetworkReply::isFinished));
+  int finished_count =
+      std::count_if(replies.constBegin(), replies.constEnd(),
+                    [](QNetworkReply* reply) { return reply->isFinished(); });
   if (finished_count == replies.size()) {
     QString cover_name = cover_names_.take(id);
     QList<CoverSearchResult> results;

src/globalsearch/globalsearch.cpp

@@ -22,6 +22,7 @@
 #include <QTimerEvent>
 #include <QUrl>
 #include <algorithm>
+#include <random>
 
 #include "core/application.h"
 #include "core/logging.h"
@@ -370,8 +371,10 @@ QStringList GlobalSearch::GetSuggestions(int count) {
     }
   }
 
+  static std::random_device rd;
+  static std::mt19937 gen(rd());
   // Randomize the suggestions
-  std::random_shuffle(ret.begin(), ret.end());
+  std::shuffle(ret.begin(), ret.end(), gen);
 
   // Only return the first count
   while (ret.length() > count) {

src/playlist/playlist.cpp

@@ -2083,9 +2083,12 @@ void Playlist::ReshuffleIndices() {
       break;
 
     case PlaylistSequence::Shuffle_All:
-    case PlaylistSequence::Shuffle_InsideAlbum:
-      std::random_shuffle(begin, end);
+    case PlaylistSequence::Shuffle_InsideAlbum: {
+      static std::random_device rd;
+      static std::mt19937 gen(rd());
+      std::shuffle(begin, end, gen);
       break;
+    }
 
     case PlaylistSequence::Shuffle_Albums: {
       QMap<int, QString> album_keys;  // real index -> key
@@ -2101,8 +2104,10 @@ void Playlist::ReshuffleIndices() {
 
       // Shuffle them
       QStringList shuffled_album_keys = album_key_set.values();
-      std::random_shuffle(shuffled_album_keys.begin(),
-                          shuffled_album_keys.end());
+
+      static std::random_device rd;
+      static std::mt19937 gen(rd());
+      std::shuffle(shuffled_album_keys.begin(), shuffled_album_keys.end(), gen);
 
       // If the user is currently playing a song, force its album to be first
       // Or if the song was not playing but it was selected, force its album