From 167d3db82e60173075e18d5c8f6df2321e3eca4b Mon Sep 17 00:00:00 2001
From: Aleksandr Kutuzov <alleteam@gmail.com>
Date: Mon, 9 Aug 2021 04:26:27 +0300
Subject: [PATCH] Separate decoding and analyzing pools. Fix crash on deleting
 analyzed object.

---
 arfariusapplication.cpp | 12 +++++++++++-
 arfariusapplication.h   | 10 ++++++++++
 player.cpp              | 37 ++++++++++++++++++++++---------------
 playlistitem.cpp        | 13 +++++++++++--
 playlistitem.h          |  4 ++++
 playlistmodel.cpp       |  8 +++++---
 6 files changed, 63 insertions(+), 21 deletions(-)

diff --git a/arfariusapplication.cpp b/arfariusapplication.cpp
index 8a640f7..01d398d 100644
--- a/arfariusapplication.cpp
+++ b/arfariusapplication.cpp
@@ -2,7 +2,9 @@
 #include <QFileOpenEvent>
 
 ArfariusApplication::ArfariusApplication(int & argc, char ** argv) :
-    QApplication(argc, argv)
+    QApplication(argc, argv),
+    decoder_thread_pool(this),
+    analyze_thread_pool(this)
 {
 }
 
@@ -16,3 +18,11 @@ bool ArfariusApplication::event(QEvent *event)
         return QApplication::event(event);
     }
 }
+
+QThreadPool* ArfariusApplication::getDecoderThreadPool() {
+    return &decoder_thread_pool;
+}
+
+QThreadPool* ArfariusApplication::getAnalyzeThreadPool() {
+    return &analyze_thread_pool;
+}
diff --git a/arfariusapplication.h b/arfariusapplication.h
index 1ddd137..82c0d8d 100644
--- a/arfariusapplication.h
+++ b/arfariusapplication.h
@@ -2,15 +2,25 @@
 #define WMPAPPLICATION_H
 
 #include <QApplication>
+#include <QThreadPool>
 #include <QUrl>
 
+#define arfariusApp (static_cast<ArfariusApplication *>(QCoreApplication::instance()))
+
 class ArfariusApplication : public QApplication
 {
     Q_OBJECT
+
+    QThreadPool decoder_thread_pool;
+    QThreadPool analyze_thread_pool;
+
 public:
     explicit ArfariusApplication(int &argc, char **argv);
     bool event(QEvent *);
 
+    QThreadPool *getDecoderThreadPool();
+    QThreadPool *getAnalyzeThreadPool();
+
 signals:
     void fileDropped(QUrl);
 
diff --git a/player.cpp b/player.cpp
index ab797e9..f25afef 100644
--- a/player.cpp
+++ b/player.cpp
@@ -1,5 +1,6 @@
 #include "player.h"
 
+#include "arfariusapplication.h"
 #include "playlistmodel.h"
 #include "playlistitem.h"
 
@@ -128,14 +129,17 @@ void Player::ejectFile()
     if (file) {
         file->cancelDecoding();
 
-        eject_future = QtConcurrent::run([this](){
-            av_sample_t *buffer = new av_sample_t[4096];
-            while (state != Player::PLAY && file) {
-                qDebug() << this << "ejectFile(): pumping samples";
-                pull(buffer, 4096);
+        eject_future = QtConcurrent::run(
+            arfariusApp->getDecoderThreadPool(),
+            [this](){
+                av_sample_t *buffer = new av_sample_t[4096];
+                while (state != Player::PLAY && file) {
+                    qDebug() << this << "ejectFile(): pumping samples";
+                    pull(buffer, 4096);
+                }
+                delete [] buffer ;
             }
-            delete [] buffer ;
-        });
+        );
         file_future.waitForFinished();
         eject_future.waitForFinished();
     }
@@ -161,15 +165,18 @@ void Player::updateItem(PlayListItem *item)
         file->setSamplerate(_sample_rate);
         file->setChannels(_channels);
         file->connectOutput(this);
-        file_future = QtConcurrent::run([this](){
-            file->decode();
-            delete file; file = 0;
-            if (quiet) {
-                quiet = false;
-            } else {
-                emit trackEnded();
+        file_future = QtConcurrent::run(
+            arfariusApp->getDecoderThreadPool(),
+            [this](){
+                file->decode();
+                delete file; file = 0;
+                if (quiet) {
+                    quiet = false;
+                } else {
+                    emit trackEnded();
+                }
             }
-        });
+        );
 
         if (state != Player::PLAY) {
             startStream();
diff --git a/playlistitem.cpp b/playlistitem.cpp
index 96c61cd..e04c918 100644
--- a/playlistitem.cpp
+++ b/playlistitem.cpp
@@ -4,6 +4,7 @@
 #include <taglib/tstring.h>
 #include <taglib/tag.h>
 
+#include "arfariusapplication.h"
 #include "avexception.h"
 #include "avsplitter.h"
 #include "avhistogram.h"
@@ -59,7 +60,7 @@ TagLib::String toString(QString str) {
  */
 
 PlayListItem::PlayListItem(QUrl s) :
-    QObject(), source(s), artist(), title(), album(), duration(-1)
+    QObject(), source(s), artist(), title(), album(), duration(-1), busy(false)
 {
 
 }
@@ -68,6 +69,10 @@ PlayListItem::~PlayListItem()
 {
 }
 
+bool PlayListItem::isBusy() {
+    return busy;
+}
+
 bool PlayListItem::isValid()
 {
     try {
@@ -235,7 +240,11 @@ bool PlayListItem::hasHistogram()
 void PlayListItem::ensureHistogram()
 {
     if (!hasHistogram()) {
-        QtConcurrent::run([&]{ auto hack = this; analyze(); hack = nullptr; });
+        busy = true;
+        QtConcurrent::run(
+            arfariusApp->getAnalyzeThreadPool(),
+            [this]{ analyze(); busy = false; }
+        );
     }
 }
 
diff --git a/playlistitem.h b/playlistitem.h
index 16f100d..f76a6d9 100644
--- a/playlistitem.h
+++ b/playlistitem.h
@@ -2,6 +2,7 @@
 #define PLAYLISTITEM_H
 
 #include <QObject>
+#include <QFuture>
 #include <QUrl>
 
 class AVFile;
@@ -13,6 +14,7 @@ class PlayListItem : public QObject
     PlayListItem(QUrl s);
     virtual ~PlayListItem();
 
+    bool isBusy();
     bool isValid();
     bool isLocalFile();
 
@@ -45,6 +47,8 @@ class PlayListItem : public QObject
     QString album;
     int     duration;
 
+    bool busy;
+
     QString getArtist();
     QString getTitle();
     QString getAlbum();
diff --git a/playlistmodel.cpp b/playlistmodel.cpp
index d0a5633..3153e71 100644
--- a/playlistmodel.cpp
+++ b/playlistmodel.cpp
@@ -1,5 +1,6 @@
 #include "playlistmodel.h"
 #include "playlistitem.h"
+#include "arfariusapplication.h"
 
 #include <QProgressDialog>
 #include <QDirIterator>
@@ -93,9 +94,10 @@ bool PlayListModel::removeRows(int row, int count, const QModelIndex &parent)
         current_item = items[current];
     }
 
-    for (int i = 0; i < count; ++i) {
-        items[row]->deleteLater();
-        items.removeAt(row);
+    for (int i = row; i < row+count; i++) {
+        while(items[i]->isBusy()) arfariusApp->processEvents(QEventLoop::AllEvents, 10);
+        items[i]->deleteLater();
+        items.removeAt(i);
     }
 
     if (current_item) {