From 5a621e811f8afd7734816392b2d1faaae4a73d1e Mon Sep 17 00:00:00 2001
From: reuk <reuk@users.noreply.github.com>
Date: Thu, 18 Nov 2021 21:37:47 +0000
Subject: [PATCH] Projucer:  Use std::async instead of ThreadPool in module
 scanner

---
 .../Modules/jucer_AvailableModulesList.h      | 152 +++++++-----------
 1 file changed, 58 insertions(+), 94 deletions(-)

diff --git a/extras/Projucer/Source/Project/Modules/jucer_AvailableModulesList.h b/extras/Projucer/Source/Project/Modules/jucer_AvailableModulesList.h
index e1494dd014..35355c0f72 100644
--- a/extras/Projucer/Source/Project/Modules/jucer_AvailableModulesList.h
+++ b/extras/Projucer/Source/Project/Modules/jucer_AvailableModulesList.h
@@ -27,6 +27,8 @@
 
 #include "jucer_ModuleDescription.h"
 
+#include <future>
+
 //==============================================================================
 class AvailableModulesList  : private AsyncUpdater
 {
@@ -39,16 +41,36 @@ public:
     //==============================================================================
     void scanPaths (const Array<File>& paths)
     {
-        auto job = createScannerJob (paths);
-        auto& ref = *job;
-
-        removePendingAndAddJob (std::move (job));
-        scanPool.waitForJobToFinish (&ref, -1);
+        scanPathsAsync (paths);
+        scanner = {};
     }
 
     void scanPathsAsync (const Array<File>& paths)
     {
-        removePendingAndAddJob (createScannerJob (paths));
+        scanner = std::async (std::launch::async, [this, paths]
+        {
+            ModuleIDAndFolderList list;
+
+            for (auto& p : paths)
+                addAllModulesInFolder (p, list);
+
+            std::sort (list.begin(), list.end(), [] (const ModuleIDAndFolder& m1,
+                                                     const ModuleIDAndFolder& m2)
+            {
+                return m1.first.compareIgnoreCase (m2.first) < 0;
+            });
+
+            {
+                const ScopedLock swapLock (lock);
+
+                if (list == modulesList)
+                    return;
+
+                modulesList.swap (list);
+            }
+
+            triggerAsyncUpdate();
+        });
     }
 
     //==============================================================================
@@ -95,85 +117,50 @@ public:
 
 private:
     //==============================================================================
-    struct ModuleScannerJob  : public ThreadPoolJob
+    static bool tryToAddModuleFromFolder (const File& path, ModuleIDAndFolderList& list)
     {
-        ModuleScannerJob (const Array<File>& paths,
-                          std::function<void (const ModuleIDAndFolderList&)>&& callback)
-            : ThreadPoolJob ("ModuleScannerJob"),
-              pathsToScan (paths),
-              completionCallback (std::move (callback))
-        {
-        }
+        ModuleDescription m (path);
 
-        JobStatus runJob() override
+        if (m.isValid()
+            && std::none_of (list.begin(), list.end(),
+                             [&m] (const ModuleIDAndFolder& element) { return element.first == m.getID(); }))
         {
-            ModuleIDAndFolderList list;
-
-            for (auto& p : pathsToScan)
-                addAllModulesInFolder (p, list);
-
-            if (! shouldExit())
-            {
-                std::sort (list.begin(), list.end(), [] (const ModuleIDAndFolder& m1,
-                                                         const ModuleIDAndFolder& m2)
-                {
-                    return m1.first.compareIgnoreCase (m2.first) < 0;
-                });
-
-                completionCallback (list);
-            }
-
-            return jobHasFinished;
+            list.push_back ({ m.getID(), path });
+            return true;
         }
 
-        static bool tryToAddModuleFromFolder (const File& path, ModuleIDAndFolderList& list)
-        {
-            ModuleDescription m (path);
+        return false;
+    }
 
-            if (m.isValid()
-                && std::none_of (list.begin(), list.end(),
-                                 [&m] (const ModuleIDAndFolder& element) { return element.first == m.getID(); }))
-            {
-                list.push_back ({ m.getID(), path });
-                return true;
-            }
+    static void addAllModulesInFolder (const File& topLevelPath, ModuleIDAndFolderList& list)
+    {
+        struct FileAndDepth
+        {
+            File file;
+            int depth;
+        };
 
-            return false;
-        }
+        std::queue<FileAndDepth> pathsToCheck;
+        pathsToCheck.push ({ topLevelPath, 0 });
 
-        static void addAllModulesInFolder (const File& topLevelPath, ModuleIDAndFolderList& list)
+        while (! pathsToCheck.empty())
         {
-            struct FileAndDepth
-            {
-                File file;
-                int depth;
-            };
+            const auto path = pathsToCheck.front();
+            pathsToCheck.pop();
 
-            std::queue<FileAndDepth> pathsToCheck;
-            pathsToCheck.push ({ topLevelPath, 0 });
+            if (tryToAddModuleFromFolder (path.file, list) || path.depth == 3)
+                continue;
 
-            while (! pathsToCheck.empty())
+            for (const auto& iter : RangedDirectoryIterator (path.file, false, "*", File::findDirectories))
             {
-                const auto path = pathsToCheck.front();
-                pathsToCheck.pop();
-
-                if (tryToAddModuleFromFolder (path.file, list) || path.depth == 3)
-                    continue;
+                if (auto* job = ThreadPoolJob::getCurrentThreadPoolJob())
+                    if (job->shouldExit())
+                        return;
 
-                for (const auto& iter : RangedDirectoryIterator (path.file, false, "*", File::findDirectories))
-                {
-                    if (auto* job = ThreadPoolJob::getCurrentThreadPoolJob())
-                        if (job->shouldExit())
-                            return;
-
-                    pathsToCheck.push({ iter.getFile(), path.depth + 1 });
-                }
+                pathsToCheck.push({ iter.getFile(), path.depth + 1 });
             }
         }
-
-        Array<File> pathsToScan;
-        std::function<void (const ModuleIDAndFolderList&)> completionCallback;
-    };
+    }
 
     //==============================================================================
     void handleAsyncUpdate() override
@@ -181,31 +168,8 @@ private:
         listeners.call ([this] (Listener& l) { l.availableModulesChanged (this); });
     }
 
-    std::unique_ptr<ThreadPoolJob> createScannerJob (const Array<File>& paths)
-    {
-        return std::make_unique<ModuleScannerJob> (paths, [this] (ModuleIDAndFolderList scannedModulesList)
-        {
-            if (scannedModulesList == modulesList)
-                return;
-
-            {
-                const ScopedLock swapLock (lock);
-                modulesList.swap (scannedModulesList);
-            }
-
-            triggerAsyncUpdate();
-        });
-    }
-
-    void removePendingAndAddJob (std::unique_ptr<ThreadPoolJob> jobToAdd)
-    {
-        scanPool.removeAllJobs (false, 100);
-        scanPool.addJob (jobToAdd.release(), true);
-    }
-
     //==============================================================================
-    ThreadPool scanPool { 1 };
-
+    std::future<void> scanner;
     ModuleIDAndFolderList modulesList;
     ListenerList<Listener> listeners;
     CriticalSection lock;