Improve asynchronous filesystem event processing

- queue and batch filesystem model updates on the main thread
  - process directory-tree updates and worker-affine listeners asynchronously
  - coalesce adjacent modified events for the same path
  - preserve captured file metadata across delayed event delivery
  - add event, path, and thread-affinity filters for listener subscriptions
  - configure optimized per-plugin filesystem subscriptions
  - make listener removal wait for active callbacks safely
  - handle self-removal without deadlocking
  - support allocation-free matching of moved source paths
  - synchronize project directory-tree mutations with active searches
  - centralize diff-view button visibility around find/replace state
  - improve code editor wrap-content and scrollbar sizing
  - add queue, listener, and filesystem-model regression tests

src/eepp/ui/models/filesystemmodel.cpp

@@ -764,12 +764,14 @@ size_t FileSystemModel::getFileIndex( Node* parent, const FileInfo& file,
 	return pos;
 }
 
-bool FileSystemModel::handleFileEventLocked( const FileEvent& event ) {
+bool FileSystemModel::handleFileEventLocked( const FileEvent& event,
+											 const FileInfo* preparedFile ) {
 	switch ( event.type ) {
 		case FileSystemEventType::Add: {
-			FileInfo file( event.directory + event.filename, false );
+			FileInfo file =
+				preparedFile ? *preparedFile : FileInfo( event.directory + event.filename, false );
 
-			if ( !file.exists() )
+			if ( !preparedFile && !file.exists() )
 				return false;
 
 			if ( ( getMode() == Mode::DirectoriesOnly && !file.isDirectory() ) ||
@@ -789,11 +791,6 @@ bool FileSystemModel::handleFileEventLocked( const FileEvent& event ) {
 			if ( childNodeExists )
 				return false;
 
-			Node* childNode = parent->createChild( file.getFileName(), *this );
-
-			if ( childNode == nullptr || childNode->getName().empty() )
-				return false;
-
 			size_t pos = getFileIndex( parent, file );
 
 			const auto& displayCfg = getDisplayConfig();
@@ -804,6 +801,15 @@ bool FileSystemModel::handleFileEventLocked( const FileEvent& event ) {
 			if ( pos == INDEX_ALREADY_EXISTS )
 				return false;
 
+			// The listener can provide metadata captured on its worker thread. Construct the node
+			// from that snapshot instead of probing the path again on the UI thread.
+			Node* childNode = eeNew( Node, ( FileInfo( file ), parent, *this ) );
+
+			if ( childNode == nullptr || childNode->getName().empty() ) {
+				eeDelete( childNode );
+				return false;
+			}
+
 			beginInsertRows( parent->index( *this, 0 ), pos, pos );
 
 			{
@@ -846,7 +852,8 @@ bool FileSystemModel::handleFileEventLocked( const FileEvent& event ) {
 			break;
 		}
 		case FileSystemEventType::Delete: {
-			FileInfo file( event.directory + event.filename, false );
+			FileInfo file =
+				preparedFile ? *preparedFile : FileInfo( event.directory + event.filename, false );
 
 			auto* child = getNodeFromPath( file.getFilepath(), file.isDirectory(), false );
 			if ( !child )
@@ -922,18 +929,19 @@ bool FileSystemModel::handleFileEventLocked( const FileEvent& event ) {
 			break;
 		}
 		case FileSystemEventType::Moved: {
-			FileInfo file( event.directory + event.filename, false );
+			FileInfo file =
+				preparedFile ? *preparedFile : FileInfo( event.directory + event.filename, false );
 			const std::string oldFilePath = FileSystem::isRelativePath( event.oldFilename )
 												? event.directory + event.oldFilename
 												: event.oldFilename;
 
-			if ( !file.exists() )
+			if ( !preparedFile && !file.exists() )
 				return false;
 
 			auto* node = getNodeFromPath( oldFilePath, false, false );
 			if ( !node ) {
 				return handleFileEventLocked(
-					{ FileSystemEventType::Add, event.directory, event.filename } );
+					{ FileSystemEventType::Add, event.directory, event.filename }, preparedFile );
 			}
 
 			ModelIndex index = node->index( *this, 0 );
@@ -1050,6 +1058,14 @@ void FileSystemModel::setupColumnNames( Translator* translator ) {
 }
 
 bool FileSystemModel::handleFileEvent( const FileEvent& event ) {
+	return handleFileEvent( event, nullptr );
+}
+
+bool FileSystemModel::handleFileEvent( const FileEvent& event, const FileInfo& file ) {
+	return handleFileEvent( event, &file );
+}
+
+bool FileSystemModel::handleFileEvent( const FileEvent& event, const FileInfo* preparedFile ) {
 	if ( !mInitOK )
 		return false;
 
@@ -1064,7 +1080,7 @@ bool FileSystemModel::handleFileEvent( const FileEvent& event ) {
 	{
 		Lock l( resourceMutex() );
 
-		ret = handleFileEventLocked( event );
+		ret = handleFileEventLocked( event, preparedFile );
 	}
 
 	if ( ret )

src/eepp/ui/tools/uidiffview.cpp

@@ -9,6 +9,7 @@
 #include <eepp/ui/doc/syntaxdefinitionmanager.hpp>
 #include <eepp/ui/doc/textdocument.hpp>
 #include <eepp/ui/tools/uidiffview.hpp>
+#include <eepp/ui/tools/uidocfindreplace.hpp>
 #include <eepp/ui/tools/uiimageviewer.hpp>
 #include <eepp/ui/uiimage.hpp>
 #include <eepp/ui/uiscenenode.hpp>
@@ -378,6 +379,14 @@ UIDiffView::UIDiffView() :
 		mLeftPlugin->registerUpdate( mLeftEditor );
 	} );
 
+	for ( auto* editor : { mEditor, mLeftEditor, mRightEditor } ) {
+		editor->on( Event::OnSizeChange, [this]( auto ) { onAutoSize(); } );
+
+		editor->on( Event::OnShowFindReplace, [this]( auto ) { updateButtonsVisibility(); } );
+
+		editor->on( Event::OnHideFindReplace, [this]( auto ) { updateButtonsVisibility(); } );
+	}
+
 	mLeftEditor->setVisible( false );
 	mRightEditor->setVisible( false );
 	mLeftEditor->setVerticalScrollBarEnabled( false );
@@ -519,7 +528,7 @@ void UIDiffView::setViewMode( ViewMode mode ) {
 
 void UIDiffView::setViewModeToggleVisible( bool visible ) {
 	mViewModeToggleVisible = visible;
-	mModeToggle->setVisible( visible );
+	updateButtonsVisibility();
 	updateModeButton();
 }
 
@@ -537,7 +546,7 @@ void UIDiffView::setCompleteView( bool complete ) {
 
 void UIDiffView::setCompleteViewToggleVisible( bool visible ) {
 	mCompleteViewToggleVisible = visible;
-	mCompleteViewToggle->setVisible( visible );
+	updateButtonsVisibility();
 	updateModeButton();
 }
 
@@ -590,9 +599,10 @@ void UIDiffView::onAutoSize() {
 		return;
 
 	if ( mEditor && mLeftEditor && !mIsImageDiff ) {
-		setPixelsSize( getPixelsSize().getWidth(), mViewMode == ViewMode::Unified
-													   ? mEditor->getPixelsSize().getHeight()
-													   : mLeftEditor->getPixelsSize().getHeight() );
+		setPixelsSize( getPixelsSize().getWidth(),
+					   std::ceil( mViewMode == ViewMode::Unified
+									  ? mEditor->getPixelsSize().getHeight()
+									  : mLeftEditor->getPixelsSize().getHeight() ) );
 	}
 
 	if ( mIsImageDiff && mLeftImageViewer && mRightImageViewer && mDiffImageViewer ) {
@@ -610,7 +620,7 @@ void UIDiffView::onAutoSize() {
 		height = std::max( height, viewImageHeight( mRightImageViewer ) );
 
 		if ( displayDiffImage )
-			height = std::max( height, viewImageHeight( mDiffImageViewer ) );
+			height = std::ceil( std::max( height, viewImageHeight( mDiffImageViewer ) ) );
 
 		setPixelsSize( getPixelsSize().getWidth(), height );
 	}
@@ -1281,12 +1291,26 @@ void UIDiffView::loadFromFile( const std::string& oldFilePath, const std::string
 	loadFromStrings( oldText, newText );
 }
 
+void UIDiffView::updateButtonsVisibility() {
+	bool findReplaceVisible{ false };
+	for ( const auto* editor : { mEditor, mLeftEditor, mRightEditor } ) {
+		const auto* findReplace = editor->getFindReplace();
+		if ( editor->isVisible() && findReplace && findReplace->isVisible() ) {
+			findReplaceVisible = true;
+			break;
+		}
+	}
+	mModeToggle->setVisible( mViewModeToggleVisible && !findReplaceVisible );
+	mCompleteViewToggle->setVisible( mCompleteViewToggleVisible && !findReplaceVisible &&
+									 !mIsImageDiff );
+}
+
 void UIDiffView::updateButtonsText() {
 	mModeToggle->setText( i18n( "diffview_side_by_side", "Side by Side" ) );
 	mModeToggle->setSelected( mViewMode != ViewMode::Unified );
 	mCompleteViewToggle->setText( i18n( "diffview_compact", "Compact" ) );
-	mCompleteViewToggle->setVisible( !mIsImageDiff );
 	mCompleteViewToggle->setSelected( !mShowCompleteView );
+	updateButtonsVisibility();
 }
 
 void UIDiffView::setSyntaxColorScheme( const SyntaxColorScheme& colorScheme ) {

src/eepp/ui/tools/uidocfindreplace.cpp

@@ -107,7 +107,7 @@ const char DOC_FIND_REPLACE_CSS[] = R"css(
 )css";
 
 const char DOC_FIND_REPLACE_XML[] = R"xml(
-<hbox class="ce_find_replace_box" layout_width="wrap_content" layout_height="wrap_content" layout_gravity="right|top" layout-margin-right="32dp">
+<hbox class="ce_find_replace_box" layout_width="wrap_content" layout_height="wrap_content" layout_gravity="right|top" margin_right="32dp">
 	<Widget class="expander" layout_width="2dp" layout_height="match_parent" />
 	<PushButton class="find_replace_toggle" layout_width="16dp" layout_height="wrap_content" padding="2dp" layout_gravity="center" />
 	<vbox layout_width="wrap_content" layout_height="wrap_content">

src/eepp/ui/uicodeeditor.cpp

@@ -2170,8 +2170,14 @@ void UICodeEditor::updateScrollBar() {
 		bool showHScroll =
 			mLongestLineWidth > viewPortWidth &&
 			( !mDocView.isWrapEnabled() || mLineWrapType == LineWrapType::LineBreakingColumn );
+		bool wasVisible = mHScrollBar->isVisible();
 		mHScrollBar->setEnabled( showHScroll );
 		mHScrollBar->setVisible( showHScroll );
+
+		if ( wasVisible != showHScroll ) {
+			// Must be updated because the horizontal scrollbar affects the visible lines count
+			notVisibleLineCount = (Int64)getTotalVisibleLines() - (Int64)getViewPortLineCount().y;
+		}
 	}
 
 	mVScrollBar->setPixelsPosition( mSize.getWidth() - mVScrollBar->getPixelsSize().getWidth(),
@@ -2190,6 +2196,8 @@ void UICodeEditor::updateScrollBar() {
 
 	setScrollY( mScroll.y );
 	mUpdatingScrollBar = false;
+
+	onAutoSize();
 }
 
 void UICodeEditor::goToLine( const TextPosition& position, bool centered, bool forceExactPosition,
@@ -4902,8 +4910,13 @@ void UICodeEditor::showFindReplace() {
 
 	if ( !mFindReplaceEnabled )
 		return;
-	if ( nullptr == mFindReplace )
+	if ( nullptr == mFindReplace ) {
 		mFindReplace = UIDocFindReplace::New( this, mDoc );
+		mFindReplace->on( Event::OnVisibleChange, [this]( auto ) {
+			sendCommonEvent( mFindReplace->isVisible() ? Event::OnShowFindReplace
+													   : Event::OnHideFindReplace );
+		} );
+	}
 	mFindReplace->setReplaceDisabled( mLocked );
 	mFindReplace->show();
 
@@ -5890,10 +5903,13 @@ void UICodeEditor::loadFromXmlNode( const pugi::xml_node& node ) {
 
 void UICodeEditor::onAutoSize() {
 	if ( mHeightPolicy == SizePolicy::WrapContent ) {
-		auto visibleLineCount = getDocumentView().getVisibleLinesCount();
+		auto visibleLineCount = getTotalVisibleLines();
 		Float lineHeight = getLineHeight();
-		Float height = lineHeight * visibleLineCount + getPixelsPadding().Top +
-					   getPixelsPadding().Bottom + getTotalTopSpace();
+		Float height = std::ceil( lineHeight * visibleLineCount + mPaddingPx.Top +
+								  mPaddingPx.Bottom + getTotalTopSpace() );
+		if ( mHorizontalScrollBarEnabled && mHScrollBar->isVisible() ) {
+			height += std::ceil( mHScrollBar->getPixelsSize().getHeight() );
+		}
 		setPixelsSize( getPixelsSize().getWidth(), height );
 	}
 }

src/tests/unit_tests/boundedeventqueue_tests.cpp

@@ -0,0 +1,108 @@
+#include "../../tools/ecode/boundedeventqueue.hpp"
+#include "utest.h"
+#include <algorithm>
+#include <atomic>
+#include <thread>
+#include <vector>
+
+using namespace ecode;
+
+UTEST( BoundedEventQueue, schedulesOnceAndDrainsInFifoOrder ) {
+	BoundedEventQueue<int> queue;
+	EXPECT_TRUE( queue.push( 1 ) );
+	EXPECT_FALSE( queue.push( 2 ) );
+	EXPECT_FALSE( queue.push( 3 ) );
+
+	std::vector<int> firstDrain;
+	queue.popUpTo( firstDrain, 2 );
+	EXPECT_EQ( firstDrain.size(), 2u );
+	EXPECT_EQ( firstDrain[0], 1 );
+	EXPECT_EQ( firstDrain[1], 2 );
+	EXPECT_TRUE( queue.finishDrain() );
+
+	std::vector<int> secondDrain;
+	queue.popUpTo( secondDrain, 2 );
+	EXPECT_EQ( secondDrain.size(), 1u );
+	EXPECT_EQ( secondDrain[0], 3 );
+	EXPECT_FALSE( queue.finishDrain() );
+	EXPECT_TRUE( queue.push( 4 ) );
+}
+
+UTEST( BoundedEventQueue, producerDuringDrainCannotLoseWakeup ) {
+	BoundedEventQueue<int> queue;
+	EXPECT_TRUE( queue.push( 1 ) );
+
+	std::vector<int> drain;
+	queue.popUpTo( drain, 1 );
+	EXPECT_FALSE( queue.push( 2 ) );
+	EXPECT_TRUE( queue.finishDrain() );
+
+	drain.clear();
+	queue.popUpTo( drain, 1 );
+	EXPECT_EQ( drain.size(), 1u );
+	EXPECT_EQ( drain[0], 2 );
+	EXPECT_FALSE( queue.finishDrain() );
+}
+
+UTEST( BoundedEventQueue, replacesOnlyMatchingLastPendingEvent ) {
+	BoundedEventQueue<int> queue;
+	EXPECT_TRUE( queue.pushOrReplaceLast( 1, []( int, int ) { return false; } ) );
+	EXPECT_FALSE( queue.pushOrReplaceLast( 2, []( int previous, int ) { return previous == 1; } ) );
+	EXPECT_FALSE( queue.pushOrReplaceLast( 3, []( int, int ) { return false; } ) );
+
+	std::vector<int> drain;
+	queue.popUpTo( drain, 4 );
+	EXPECT_EQ( drain.size(), 2u );
+	EXPECT_EQ( drain[0], 2 );
+	EXPECT_EQ( drain[1], 3 );
+	EXPECT_FALSE( queue.finishDrain() );
+}
+
+UTEST( BoundedEventQueue, acceptsConcurrentProducersWithoutLoss ) {
+	static constexpr int ProducerCount = 4;
+	static constexpr int EventsPerProducer = 1000;
+	BoundedEventQueue<int> queue;
+	std::atomic<int> scheduleCount{ 0 };
+	std::vector<std::thread> producers;
+
+	for ( int producer = 0; producer < ProducerCount; ++producer ) {
+		producers.emplace_back( [producer, &queue, &scheduleCount] {
+			for ( int event = 0; event < EventsPerProducer; ++event ) {
+				if ( queue.push( producer * EventsPerProducer + event ) )
+					++scheduleCount;
+			}
+		} );
+	}
+	for ( auto& producer : producers )
+		producer.join();
+
+	EXPECT_EQ( scheduleCount.load(), 1 );
+	std::vector<int> received;
+	do {
+		queue.popUpTo( received, received.size() + 37 );
+	} while ( queue.finishDrain() );
+
+	EXPECT_EQ( received.size(), static_cast<std::size_t>( ProducerCount * EventsPerProducer ) );
+	int lastEvent[ProducerCount] = { -1, -1, -1, -1 };
+	for ( int event : received ) {
+		const int producer = event / EventsPerProducer;
+		EXPECT_EQ( event, producer * EventsPerProducer + ++lastEvent[producer] );
+	}
+	std::sort( received.begin(), received.end() );
+	for ( int event = 0; event < ProducerCount * EventsPerProducer; ++event )
+		EXPECT_EQ( received[event], event );
+}
+
+UTEST( BoundedEventQueue, clearCancelsPendingDrainState ) {
+	BoundedEventQueue<int> queue;
+	EXPECT_TRUE( queue.push( 1 ) );
+	EXPECT_FALSE( queue.push( 2 ) );
+	queue.clear();
+	EXPECT_TRUE( queue.push( 3 ) );
+
+	std::vector<int> drain;
+	queue.popUpTo( drain, 4 );
+	EXPECT_EQ( drain.size(), 1u );
+	EXPECT_EQ( drain[0], 3 );
+	EXPECT_FALSE( queue.finishDrain() );
+}

src/tests/unit_tests/filesystemlistener_tests.cpp

@@ -0,0 +1,94 @@
+#include "../../tools/ecode/filesystemlistener.hpp"
+#include "utest.h"
+#include <condition_variable>
+#include <future>
+#include <mutex>
+#include <thread>
+
+using namespace ecode;
+
+UTEST( FileSystemListenerOptions, filtersByEventTypeAndPathPrefix ) {
+	FileSystemListener::ListenerOptions options;
+	FileSystemListenerFilter filter;
+	filter.eventTypes = FileSystemListener::eventTypeMask( FileSystemEventType::Add ) |
+						FileSystemListener::eventTypeMask( FileSystemEventType::Modified );
+	filter.path = "/tmp/ecode-ipc/";
+	options.filters.emplace_back( std::move( filter ) );
+
+	EXPECT_TRUE( options.matches( FileSystemEventType::Add, "/tmp/ecode-ipc/request" ) );
+	EXPECT_TRUE( options.matches( FileSystemEventType::Modified, "/tmp/ecode-ipc/request" ) );
+	EXPECT_FALSE( options.matches( FileSystemEventType::Delete, "/tmp/ecode-ipc/request" ) );
+	EXPECT_FALSE( options.matches( FileSystemEventType::Add, "/tmp/other/request" ) );
+}
+
+UTEST( FileSystemListenerOptions, matchesAnyFilterWithoutDuplicateSemantics ) {
+	FileSystemListener::ListenerOptions options;
+	FileSystemListenerFilter config;
+	config.eventTypes = FileSystemListener::eventTypeMask( FileSystemEventType::Modified );
+	config.path = "/tmp/plugin.json";
+	config.pathMatch = FileEventPathMatch::Exact;
+	options.filters.emplace_back( std::move( config ) );
+	FileSystemListenerFilter workspace;
+	workspace.path = "/tmp/workspace/";
+	options.filters.emplace_back( std::move( workspace ) );
+
+	EXPECT_TRUE( options.matches( FileSystemEventType::Modified, "/tmp/plugin.json" ) );
+	EXPECT_FALSE( options.matches( FileSystemEventType::Add, "/tmp/plugin.json" ) );
+	EXPECT_TRUE( options.matches( FileSystemEventType::Add, "/tmp/workspace/file.cpp" ) );
+	EXPECT_FALSE( options.matches( FileSystemEventType::Modified, "/tmp/plugin.json.backup" ) );
+	EXPECT_TRUE(
+		options.matchesJoinedPath( FileSystemEventType::Moved, "/tmp/workspace/", 0, "file.cpp" ) );
+	EXPECT_TRUE( options.matchesJoinedPath( FileSystemEventType::Moved, "/tmp/workspace", '/',
+											"file.cpp" ) );
+}
+
+UTEST( FileSystemListenerOptions, defaultsToAllEventsAndPathsOnMainThread ) {
+	FileSystemListener::ListenerOptions options;
+	EXPECT_EQ( options.affinity, FileSystemListener::ThreadAffinity::Main );
+	EXPECT_TRUE( options.matches( FileSystemEventType::Add, "/any/path" ) );
+	EXPECT_TRUE( options.matches( FileSystemEventType::Delete, "/another/path" ) );
+	EXPECT_TRUE( options.matches( FileSystemEventType::Modified, "relative/path" ) );
+	EXPECT_TRUE( options.matches( FileSystemEventType::Moved, "" ) );
+}
+
+UTEST( FileSystemListener, removalWaitsForActiveCallback ) {
+	FileSystemListenerCallbackState callbackState;
+	std::mutex mutex;
+	std::condition_variable condition;
+	bool callbackBegan{ false };
+	bool callbackStarted{ false };
+	bool releaseCallback{ false };
+	std::thread callbackThread( [&] {
+		callbackBegan = callbackState.beginCallback();
+		std::unique_lock<std::mutex> lock( mutex );
+		callbackStarted = true;
+		condition.notify_all();
+		condition.wait( lock, [&] { return releaseCallback; } );
+		lock.unlock();
+		callbackState.endCallback();
+	} );
+	{
+		std::unique_lock<std::mutex> lock( mutex );
+		condition.wait( lock, [&] { return callbackStarted; } );
+	}
+
+	auto removal = std::async( std::launch::async, [&] { callbackState.removeAndWait( false ); } );
+	EXPECT_EQ( removal.wait_for( std::chrono::milliseconds( 20 ) ), std::future_status::timeout );
+	{
+		std::lock_guard<std::mutex> lock( mutex );
+		releaseCallback = true;
+	}
+	condition.notify_all();
+	callbackThread.join();
+	removal.get();
+	EXPECT_TRUE( callbackBegan );
+	EXPECT_FALSE( callbackState.beginCallback() );
+}
+
+UTEST( FileSystemListener, callbackCanRemoveItself ) {
+	FileSystemListenerCallbackState callbackState;
+	ASSERT_TRUE( callbackState.beginCallback() );
+	callbackState.removeAndWait( true );
+	callbackState.endCallback();
+	EXPECT_FALSE( callbackState.beginCallback() );
+}

src/tests/unit_tests/modeloperations_tests.cpp

@@ -298,6 +298,29 @@ UTEST( FileSystemModelMove, keepsUnopenedDestinationBranchLazy ) {
 				 nullptr );
 }
 
+UTEST( FileSystemModelEvents, preparedMetadataSurvivesDelayedAddDelivery ) {
+	TempTree tree;
+	auto directory = tree.path / "directory";
+	auto path = directory / "transient.txt";
+	std::filesystem::create_directories( directory );
+
+	auto model = FileSystemModel::New( tree.path.string() );
+	ASSERT_TRUE( model->getNodeFromPath( directory.string(), true ) != nullptr );
+
+	std::FILE* file = std::fopen( path.string().c_str(), "wb" );
+	ASSERT_TRUE( file != nullptr );
+	std::fclose( file );
+	FileInfo preparedFile( path.string(), false );
+	ASSERT_TRUE( preparedFile.exists() );
+	std::filesystem::remove( path );
+
+	ASSERT_TRUE(
+		model->handleFileEvent( { FileSystemEventType::Add,
+								  directory.string() + FileSystem::getOSSlash(), "transient.txt" },
+								preparedFile ) );
+	ASSERT_TRUE( model->getNodeFromPath( path.string(), false, false ) != nullptr );
+}
+
 static ModelIndex indexOfNode( const FileSystemModel& model, const void* node,
 							   const ModelIndex& parent = {} ) {
 	for ( Int64 row = 0; row < (Int64)model.rowCount( parent ); ++row ) {

src/tools/ecode/boundedeventqueue.hpp

@@ -0,0 +1,69 @@
+#ifndef ECODE_BOUNDEDEVENTQUEUE_HPP
+#define ECODE_BOUNDEDEVENTQUEUE_HPP
+
+#include <cstddef>
+#include <deque>
+#include <mutex>
+#include <utility>
+
+namespace ecode {
+
+// Thread-safe producer queue with a single-consumer scheduling handshake.
+// push() returns true exactly when the caller must schedule the consumer.
+// Once a drain completes, finishDrain() either transfers responsibility to
+// the next drain or atomically makes the next producer responsible for it.
+template <typename T> class BoundedEventQueue {
+  public:
+	bool push( T&& event ) {
+		std::lock_guard<std::mutex> lock( mMutex );
+		mEvents.emplace_back( std::move( event ) );
+		if ( mDrainScheduled )
+			return false;
+		mDrainScheduled = true;
+		return true;
+	}
+
+	template <typename Predicate> bool pushOrReplaceLast( T&& event, Predicate&& shouldReplace ) {
+		std::lock_guard<std::mutex> lock( mMutex );
+		if ( !mEvents.empty() && shouldReplace( mEvents.back(), event ) ) {
+			mEvents.back() = std::move( event );
+			return false;
+		}
+		mEvents.emplace_back( std::move( event ) );
+		if ( mDrainScheduled )
+			return false;
+		mDrainScheduled = true;
+		return true;
+	}
+
+	template <typename Container> void popUpTo( Container& events, std::size_t maxEvents ) {
+		std::lock_guard<std::mutex> lock( mMutex );
+		while ( !mEvents.empty() && events.size() < maxEvents ) {
+			events.emplace_back( std::move( mEvents.front() ) );
+			mEvents.pop_front();
+		}
+	}
+
+	bool finishDrain() {
+		std::lock_guard<std::mutex> lock( mMutex );
+		if ( !mEvents.empty() )
+			return true;
+		mDrainScheduled = false;
+		return false;
+	}
+
+	void clear() {
+		std::lock_guard<std::mutex> lock( mMutex );
+		mEvents.clear();
+		mDrainScheduled = false;
+	}
+
+  private:
+	std::mutex mMutex;
+	std::deque<T> mEvents;
+	bool mDrainScheduled{ false };
+};
+
+} // namespace ecode
+
+#endif // ECODE_BOUNDEDEVENTQUEUE_HPP

src/tools/ecode/ecode.cpp

@@ -5059,12 +5059,16 @@ void App::init( InitParameters& params ) {
 		mFileWatcher->addWatch( mPidPath, mFileSystemListener );
 		mFileWatcher->watch();
 		mPluginManager->setFileSystemListener( mFileSystemListener );
-		mIpcListenerId =
-			mFileSystemListener->addListener( [this]( const FileEvent& fe, const FileInfo& fi ) {
-				if ( !( ( fe.type == FileSystemEventType::Add ||
-						  fe.type == FileSystemEventType::Modified ) &&
-						fe.directory == mPidPath ) )
-					return;
+		FileSystemListener::ListenerOptions ipcListenerOptions;
+		FileSystemListenerFilter ipcListenerFilter;
+		ipcListenerFilter.eventTypes =
+			FileSystemListener::eventTypeMask( FileSystemEventType::Add ) |
+			FileSystemListener::eventTypeMask( FileSystemEventType::Modified );
+		ipcListenerFilter.path = mPidPath;
+		ipcListenerOptions.filters.emplace_back( std::move( ipcListenerFilter ) );
+		ipcListenerOptions.affinity = FileSystemListener::ThreadAffinity::Worker;
+		mIpcListenerId = mFileSystemListener->addListener(
+			[this]( const FileEvent&, const FileInfo& fi ) {
 				std::string path;
 				FileSystem::fileGet( fi.getFilepath(), path );
 				String::trimInPlace( path, ' ' );
@@ -5091,7 +5095,8 @@ void App::init( InitParameters& params ) {
 					} );
 				}
 				FileSystem::fileRemove( fi.getFilepath() );
-			} );
+			},
+			std::move( ipcListenerOptions ) );
 #endif
 
 		mNotificationCenter = std::make_unique<NotificationCenter>(

src/tools/ecode/filesystemlistener.cpp

@@ -1,4 +1,5 @@
 #include "filesystemlistener.hpp"
+#include <eepp/core/small_vector.hpp>
 #include <eepp/scene/actionmanager.hpp>
 #include <eepp/scene/scenemanager.hpp>
 #include <eepp/system/filesystem.hpp>
@@ -8,6 +9,26 @@
 
 namespace ecode {
 
+static thread_local const void* currentFileSystemListenerCallback{ nullptr };
+
+class FileSystemListenerCallbackGuard {
+  public:
+	FileSystemListenerCallbackGuard( FileSystemListenerCallbackState& state,
+									 const void* listener ) :
+		mState( state ), mPreviousCallback( currentFileSystemListenerCallback ) {
+		currentFileSystemListenerCallback = listener;
+	}
+
+	~FileSystemListenerCallbackGuard() {
+		currentFileSystemListenerCallback = mPreviousCallback;
+		mState.endCallback();
+	}
+
+  private:
+	FileSystemListenerCallbackState& mState;
+	const void* mPreviousCallback;
+};
+
 std::string getFileSystemEventTypeName( FileSystemEventType action ) {
 	switch ( action ) {
 		case FileSystemEventType::Add:
@@ -45,6 +66,17 @@ FileSystemListener::~FileSystemListener() {
 	// block instead of an atomic flag.
 	eeASSERT( !Engine::existsSingleton() || Engine::isMainThread() );
 	*mLifetime = false;
+	SmallVector<std::shared_ptr<Listener>, 8> listeners;
+	{
+		Lock l( mCbsMutex );
+		for ( auto& listener : mCbs )
+			listeners.emplace_back( std::move( listener.second ) );
+		mCbs.clear();
+	}
+	for ( const auto& listener : listeners )
+		listener->callbackState.removeAndWait( currentFileSystemListenerCallback ==
+											   listener.get() );
+	mPendingEvents.clear();
 	if ( auto* scene = SceneManager::instance()->getUISceneNode() )
 		scene->getActionManager()->removeActionsByTagFromTarget( scene, mEventActionTag );
 }
@@ -56,35 +88,78 @@ static inline bool endsWithSlash( const std::string& dir ) {
 void FileSystemListener::handleFileAction( efsw::WatchID, const std::string& dir,
 										   const std::string& filename, efsw::Action action,
 										   const std::string& oldFilename ) {
-	// The whole logical event (model, directory tree, open documents,
-	// callbacks) must run on the main thread in its original order: the model
-	// update used to complete synchronously before the other consequences, and
-	// all of them touch UI-owned state. The destructor cancels queued actions
-	// (tagged with mEventActionTag), so a runnable can never outlive the
-	// listener.
-	if ( !Engine::isMainThread() ) {
+	eeASSERT( !Engine::isMainThread() );
+	FileEvent event( (FileSystemEventType)action, dir, filename, oldFilename );
+	FileInfo file( ( endsWithSlash( dir ) ? dir : ( dir + FileSystem::getOSSlash() ) ) + filename,
+				   false );
+	std::shared_ptr<ProjectDirectoryTree> dirTree;
+	{
+		Lock l( mDirTreeMutex );
+		dirTree = mDirTree;
+	}
+	if ( dirTree && action != efsw::Actions::Modified )
+		dirTree->onChange( (ProjectDirectoryTree::Action)action, file, oldFilename );
+	// Worker listeners receive the event early. The queued phase is independent:
+	// it updates the model and documents and then dispatches main-thread listeners.
+	dispatchCallbacks( ThreadAffinity::Worker, event, file, file.getFilepath(), true );
+	enqueueFileAction( { std::move( event ), std::move( file ), action } );
+}
+
+void FileSystemListener::enqueueFileAction( PendingFileAction&& event ) {
+	auto* scene = SceneManager::instance()->getUISceneNode();
+	if ( !scene )
+		return;
+
+	const bool schedule = mPendingEvents.pushOrReplaceLast(
+		std::move( event ), []( const PendingFileAction& previous, const PendingFileAction& next ) {
+			return previous.action == efsw::Actions::Modified &&
+				   next.action == efsw::Actions::Modified &&
+				   previous.file.getFilepath() == next.file.getFilepath();
+		} );
+	if ( schedule ) {
+		scene->runOnMainThread(
+			[lifetime = mLifetime, this]() {
+				if ( lifetime->load( std::memory_order_acquire ) )
+					drainFileActions();
+			},
+			Time::Zero, mEventActionTag );
+	}
+}
+
+void FileSystemListener::drainFileActions() {
+	eeASSERT( Engine::isMainThread() );
+	static constexpr std::size_t MaxEventsPerDrain = 64;
+	SmallVector<PendingFileAction, MaxEventsPerDrain> events;
+	mPendingEvents.popUpTo( events, MaxEventsPerDrain );
+
+	for ( auto& event : events )
+		processFileAction( std::move( event ) );
+
+	if ( mPendingEvents.finishDrain() ) {
 		if ( auto* scene = SceneManager::instance()->getUISceneNode() ) {
 			scene->runOnMainThread(
-				[lifetime = mLifetime, this, dir, filename, action, oldFilename]() {
-					if ( !lifetime->load( std::memory_order_acquire ) )
-						return;
-					handleFileAction( 0, dir, filename, action, oldFilename );
+				[lifetime = mLifetime, this]() {
+					if ( lifetime->load( std::memory_order_acquire ) )
+						drainFileActions();
 				},
 				Time::Zero, mEventActionTag );
-			return;
+		} else {
+			mPendingEvents.clear();
 		}
-		// No scene node: cannot safely touch UI state from this thread.
-		return;
 	}
+}
 
-	FileInfo file( ( endsWithSlash( dir ) ? dir : ( dir + FileSystem::getOSSlash() ) ) + filename );
+void FileSystemListener::processFileAction( PendingFileAction&& pending ) {
+	eeASSERT( Engine::isMainThread() );
+	FileEvent& event = pending.event;
+	const std::string& eventPath = pending.file.getFilepath();
+	FileInfo file( pending.file );
+	const efsw::Action action = pending.action;
 
 	switch ( action ) {
 		case efsw::Actions::Add:
 		case efsw::Actions::Delete:
 		case efsw::Actions::Moved: {
-			FileEvent event( (FileSystemEventType)action, dir, filename, oldFilename );
-
 			if ( Log::instance() && Log::instance()->getLogLevelThreshold() == LogLevel::Debug ) {
 				std::string txt =
 					"DIR ( " + event.directory + " ) FILE ( " +
@@ -97,14 +172,12 @@ void FileSystemListener::handleFileAction( efsw::WatchID, const std::string& dir
 			}
 
 			if ( mFileSystemModel )
-				mFileSystemModel->handleFileEvent( event );
-
-			if ( mDirTree )
-				mDirTree->onChange( (ProjectDirectoryTree::Action)action, file, oldFilename );
+				mFileSystemModel->handleFileEvent( event, file );
 
 			if ( action == efsw::Actions::Moved ) {
-				FileInfo oldFile( FileSystem::isRelativePath( oldFilename ) ? dir + oldFilename
-																			: oldFilename );
+				FileInfo oldFile( FileSystem::isRelativePath( event.oldFilename )
+									  ? event.directory + event.oldFilename
+									  : event.oldFilename );
 				if ( file.isLink() )
 					file = FileInfo( file.linksTo() );
 
@@ -125,11 +198,7 @@ void FileSystemListener::handleFileAction( efsw::WatchID, const std::string& dir
 			if ( isFileOpen( file ) )
 				notifyChange( file );
 
-			Lock l( mCbsMutex );
-			if ( !mCbs.empty() ) {
-				for ( const auto& cb : mCbs )
-					cb.second( event, file );
-			}
+			dispatchCallbacks( ThreadAffinity::Main, event, file, eventPath );
 
 			break;
 		}
@@ -139,35 +208,84 @@ void FileSystemListener::handleFileAction( efsw::WatchID, const std::string& dir
 			if ( isFileOpen( file ) )
 				notifyChange( file );
 
-			Lock l( mCbsMutex );
-			if ( !mCbs.empty() ) {
-				FileEvent event( (FileSystemEventType)action, dir, filename, oldFilename );
-				for ( const auto& cb : mCbs )
-					cb.second( event, file );
-			}
+			dispatchCallbacks( ThreadAffinity::Main, event, file, eventPath );
 		}
 	}
 }
 
 void FileSystemListener::setDirTree( const std::shared_ptr<ProjectDirectoryTree>& dirTree ) {
+	Lock l( mDirTreeMutex );
 	mDirTree = dirTree;
 }
 
 Uint64 FileSystemListener::addListener( const FileEventFn& fn ) {
+	return addListener( fn, {} );
+}
+
+Uint64 FileSystemListener::addListener( const FileEventFn& fn, ListenerOptions options ) {
 	Lock l( mCbsMutex );
 	Uint64 id = ++mLastId;
-	mCbs[id] = fn;
+	mCbs[id] = std::make_shared<Listener>( fn, std::move( options ) );
 	return id;
 }
 
-bool FileSystemListener::removeListener( const Uint64& id ) {
-	Lock l( mCbsMutex );
-	auto it = mCbs.find( id );
-	if ( it != mCbs.end() ) {
-		mCbs.erase( it );
-		return true;
+void FileSystemListener::dispatchCallbacks( ThreadAffinity affinity, const FileEvent& event,
+											const FileInfo& file, const std::string& eventPath,
+											bool resolveLinks ) {
+	SmallVector<std::shared_ptr<Listener>, 8> callbacks;
+	{
+		Lock l( mCbsMutex );
+		for ( const auto& entry : mCbs ) {
+			const Listener& listener = *entry.second;
+			if ( listener.options.affinity != affinity )
+				continue;
+			bool matches = listener.options.matches( event.type, eventPath );
+			if ( !matches && event.type == FileSystemEventType::Moved &&
+				 !event.oldFilename.empty() ) {
+				if ( FileSystem::isRelativePath( event.oldFilename ) ) {
+					matches = listener.options.matchesJoinedPath(
+						event.type, event.directory,
+						endsWithSlash( event.directory ) ? 0 : FileSystem::getOSSlash()[0],
+						event.oldFilename );
+				} else {
+					matches = listener.options.matches( event.type, event.oldFilename );
+				}
+			}
+			if ( matches )
+				callbacks.emplace_back( entry.second );
+		}
 	}
-	return false;
+	if ( callbacks.empty() )
+		return;
+	auto invokeCallback = [&]( const std::shared_ptr<Listener>& listener,
+							   const FileInfo& callbackFile ) {
+		if ( !listener->callbackState.beginCallback() )
+			return;
+		FileSystemListenerCallbackGuard guard( listener->callbackState, listener.get() );
+		listener->callback( event, callbackFile );
+	};
+	if ( resolveLinks && file.isLink() ) {
+		FileInfo resolvedFile( file.linksTo() );
+		for ( const auto& listener : callbacks )
+			invokeCallback( listener, resolvedFile );
+		return;
+	}
+	for ( const auto& listener : callbacks )
+		invokeCallback( listener, file );
+}
+
+bool FileSystemListener::removeListener( const Uint64& id ) {
+	std::shared_ptr<Listener> listener;
+	{
+		Lock l( mCbsMutex );
+		auto it = mCbs.find( id );
+		if ( it == mCbs.end() )
+			return false;
+		listener = std::move( it->second );
+		mCbs.erase( it );
+	}
+	listener->callbackState.removeAndWait( currentFileSystemListenerCallback == listener.get() );
+	return true;
 }
 
 bool FileSystemListener::isFileOpen( const FileInfo& file ) {

src/tools/ecode/filesystemlistener.hpp

@@ -1,8 +1,11 @@
 #ifndef ECODE_FILESYSTEMLISTENER_HPP
 #define ECODE_FILESYSTEMLISTENER_HPP
 
+#include "boundedeventqueue.hpp"
+#include "filesystemlisteneroptions.hpp"
 #include "projectdirectorytree.hpp"
 #include <atomic>
+#include <condition_variable>
 #include <eepp/system/fileinfo.hpp>
 #include <eepp/ui/models/filesystemmodel.hpp>
 #include <eepp/ui/tools/uicodeeditorsplitter.hpp>
@@ -17,9 +20,44 @@ using namespace EE::UI::Tools;
 
 namespace ecode {
 
+class FileSystemListenerCallbackState {
+  public:
+	bool beginCallback() {
+		std::lock_guard<std::mutex> lock( mMutex );
+		if ( mRemoved )
+			return false;
+		++mActiveCallbacks;
+		return true;
+	}
+
+	void endCallback() {
+		std::lock_guard<std::mutex> lock( mMutex );
+		if ( --mActiveCallbacks == 0 )
+			mCondition.notify_all();
+	}
+
+	void removeAndWait( bool calledFromThisListener ) {
+		std::unique_lock<std::mutex> lock( mMutex );
+		mRemoved = true;
+		if ( !calledFromThisListener )
+			mCondition.wait( lock, [this] { return mActiveCallbacks == 0; } );
+	}
+
+  private:
+	std::mutex mMutex;
+	std::condition_variable mCondition;
+	std::size_t mActiveCallbacks{ 0 };
+	bool mRemoved{ false };
+};
+
 class FileSystemListener : public efsw::FileWatchListener {
   public:
 	typedef std::function<void( const FileEvent&, const FileInfo& )> FileEventFn;
+	using ThreadAffinity = FileEventThreadAffinity;
+	using ListenerOptions = FileSystemListenerOptions;
+	static constexpr FileEventTypeMask eventTypeMask( FileSystemEventType type ) {
+		return fileEventTypeMask( type );
+	}
 
 	FileSystemListener( UICodeEditorSplitter* codeSplitter,
 						std::shared_ptr<FileSystemModel> fileSystemModel,
@@ -36,22 +74,49 @@ class FileSystemListener : public efsw::FileWatchListener {
 
 	Uint64 addListener( const FileEventFn& fn );
 
+	Uint64 addListener( const FileEventFn& fn, ListenerOptions options );
+
 	bool removeListener( const Uint64& id );
 
   protected:
+	struct PendingFileAction {
+		FileEvent event;
+		FileInfo file;
+		efsw::Action action;
+	};
+	struct Listener {
+		FileEventFn callback;
+		ListenerOptions options;
+		FileSystemListenerCallbackState callbackState;
+
+		Listener( FileEventFn callback, ListenerOptions options ) :
+			callback( std::move( callback ) ), options( std::move( options ) ) {}
+	};
+
 	UICodeEditorSplitter* mSplitter;
 	std::shared_ptr<FileSystemModel> mFileSystemModel;
 	std::shared_ptr<ProjectDirectoryTree> mDirTree;
 	std::atomic<Uint64> mLastId{ 0 };
-	std::unordered_map<Uint64, FileEventFn> mCbs;
+	std::unordered_map<Uint64, std::shared_ptr<Listener>> mCbs;
 	std::vector<std::string> mIgnoredFiles;
 	Mutex mCbsMutex;
+	Mutex mDirTreeMutex;
+	BoundedEventQueue<PendingFileAction> mPendingEvents;
 	// Tag of the queued main-thread file-event actions; the destructor cancels
 	// them and marks the lifetime token dead so a queued runnable can never
 	// dereference the destroyed listener.
 	Uint64 mEventActionTag{ 0 };
 	std::shared_ptr<std::atomic<bool>> mLifetime;
 
+	void enqueueFileAction( PendingFileAction&& event );
+
+	void drainFileActions();
+
+	void processFileAction( PendingFileAction&& event );
+
+	void dispatchCallbacks( ThreadAffinity affinity, const FileEvent& event, const FileInfo& file,
+							const std::string& eventPath, bool resolveLinks = false );
+
 	bool isFileOpen( const FileInfo& file );
 
 	void notifyChange( const FileInfo& file );

src/tools/ecode/filesystemlisteneroptions.hpp

@@ -0,0 +1,92 @@
+#ifndef ECODE_FILESYSTEMLISTENEROPTIONS_HPP
+#define ECODE_FILESYSTEMLISTENEROPTIONS_HPP
+
+#include <eepp/core.hpp>
+#include <eepp/ui/models/filesystemmodel.hpp>
+
+namespace ecode {
+
+using namespace EE::UI::Models;
+using FileEventTypeMask = EE::Uint32;
+
+enum class FileEventThreadAffinity { Main, Worker };
+enum class FileEventPathMatch { Prefix, Exact };
+
+static constexpr FileEventTypeMask fileEventTypeMask( FileSystemEventType type ) {
+	return 1u << static_cast<EE::Uint32>( type );
+}
+
+struct FileSystemListenerFilter {
+	FileEventTypeMask eventTypes{ 0xFFFFFFFFu };
+	std::string path;
+	FileEventPathMatch pathMatch{ FileEventPathMatch::Prefix };
+
+	bool matches( FileSystemEventType type, const std::string& filePath ) const {
+		if ( ( eventTypes & fileEventTypeMask( type ) ) == 0 )
+			return false;
+		if ( path.empty() )
+			return true;
+		return pathMatch == FileEventPathMatch::Exact
+				   ? filePath == path
+				   : filePath.compare( 0, path.size(), path ) == 0;
+	}
+
+	bool matchesJoinedPath( FileSystemEventType type, const std::string& directory, char separator,
+							const std::string& filename ) const {
+		if ( ( eventTypes & fileEventTypeMask( type ) ) == 0 )
+			return false;
+		if ( path.empty() )
+			return true;
+		const std::size_t joinedSize =
+			directory.size() + ( separator != 0 ? 1 : 0 ) + filename.size();
+		if ( path.size() > joinedSize ||
+			 ( pathMatch == FileEventPathMatch::Exact && path.size() != joinedSize ) )
+			return false;
+
+		std::size_t pathPos = 0;
+		auto matchesPart = [&]( const char* data, std::size_t size ) {
+			const std::size_t count = std::min( size, path.size() - pathPos );
+			if ( count != 0 && path.compare( pathPos, count, data, count ) != 0 )
+				return false;
+			pathPos += count;
+			return true;
+		};
+		if ( !matchesPart( directory.data(), directory.size() ) )
+			return false;
+		if ( separator != 0 && pathPos < path.size() ) {
+			if ( !matchesPart( &separator, 1 ) )
+				return false;
+		}
+		return pathPos == path.size() || matchesPart( filename.data(), filename.size() );
+	}
+};
+
+struct FileSystemListenerOptions {
+	std::vector<FileSystemListenerFilter> filters;
+	FileEventThreadAffinity affinity{ FileEventThreadAffinity::Main };
+
+	bool matches( FileSystemEventType type, const std::string& filePath ) const {
+		if ( filters.empty() )
+			return true;
+		for ( const auto& filter : filters ) {
+			if ( filter.matches( type, filePath ) )
+				return true;
+		}
+		return false;
+	}
+
+	bool matchesJoinedPath( FileSystemEventType type, const std::string& directory, char separator,
+							const std::string& filename ) const {
+		if ( filters.empty() )
+			return true;
+		for ( const auto& filter : filters ) {
+			if ( filter.matchesJoinedPath( type, directory, separator, filename ) )
+				return true;
+		}
+		return false;
+	}
+};
+
+} // namespace ecode
+
+#endif // ECODE_FILESYSTEMLISTENEROPTIONS_HPP

src/tools/ecode/plugins/autocomplete/autocompleteplugin.cpp

@@ -674,6 +674,23 @@ void AutoCompletePlugin::onFileSystemEvent( const FileEvent& ev, const FileInfo&
 	}
 }
 
+FileSystemListenerOptions AutoCompletePlugin::getFileSystemListenerOptions() const {
+	auto options = Plugin::getFileSystemListenerOptions();
+	const auto eventTypes = fileEventTypeMask( FileSystemEventType::Add ) |
+							fileEventTypeMask( FileSystemEventType::Delete ) |
+							fileEventTypeMask( FileSystemEventType::Modified ) |
+							fileEventTypeMask( FileSystemEventType::Moved );
+	for ( const auto* path : { &mUserSnippetsPath, &mVSCodeSnippetsPath, &mEcodeSnippetsPath } ) {
+		if ( path->empty() )
+			continue;
+		FileSystemListenerFilter filter;
+		filter.eventTypes = eventTypes;
+		filter.path = *path;
+		options.filters.emplace_back( std::move( filter ) );
+	}
+	return options;
+}
+
 void AutoCompletePlugin::onRegister( UICodeEditor* editor ) {
 	registerSnippetLocatorProvider();
 	Lock l( mDocMutex );

src/tools/ecode/plugins/autocomplete/autocompleteplugin.hpp

@@ -109,6 +109,7 @@ class AutoCompletePlugin : public Plugin {
 	bool onMouseDoubleClick( UICodeEditor*, const Vector2i&, const Uint32& ) override;
 	bool onMouseMove( UICodeEditor*, const Vector2i&, const Uint32& ) override;
 	void onFileSystemEvent( const FileEvent&, const FileInfo& ) override;
+	FileSystemListenerOptions getFileSystemListenerOptions() const override;
 	void onLoadProject( const std::string& projectFolder,
 						const std::string& projectStatePath ) override;
 

src/tools/ecode/plugins/git/gitplugin.cpp

@@ -562,6 +562,17 @@ void GitPlugin::onFileSystemEvent( const FileEvent& ev, const FileInfo& file ) {
 	updateUI();
 }
 
+FileSystemListenerOptions GitPlugin::getFileSystemListenerOptions() const {
+	auto options = Plugin::getFileSystemListenerOptions();
+	const auto& workspace = getManager()->getWorkspaceFolder();
+	if ( !workspace.empty() ) {
+		FileSystemListenerFilter filter;
+		filter.path = workspace;
+		options.filters.emplace_back( std::move( filter ) );
+	}
+	return options;
+}
+
 void GitPlugin::displayTooltip( UICodeEditor* editor, const Git::Blame& blame,
 								const Vector2f& position ) {
 	// HACK: Gets the old font style to restore it when the tooltip is hidden

src/tools/ecode/plugins/git/gitplugin.hpp

@@ -54,6 +54,8 @@ class GitPlugin : public PluginBase {
 
 	void onFileSystemEvent( const FileEvent& ev, const FileInfo& file ) override;
 
+	FileSystemListenerOptions getFileSystemListenerOptions() const override;
+
 	void onRegister( UICodeEditor* ) override;
 
 	void onUnregister( UICodeEditor* ) override;

src/tools/ecode/plugins/plugin.cpp

@@ -110,6 +110,16 @@ void Plugin::onFileSystemEvent( const FileEvent& ev, const FileInfo& file ) {
 	}
 }
 
+FileSystemListenerOptions Plugin::getFileSystemListenerOptions() const {
+	FileSystemListenerOptions options;
+	FileSystemListenerFilter filter;
+	filter.eventTypes = fileEventTypeMask( FileSystemEventType::Modified );
+	filter.path = mConfigPath;
+	filter.pathMatch = FileEventPathMatch::Exact;
+	options.filters.emplace_back( std::move( filter ) );
+	return options;
+}
+
 void Plugin::setReady( Time loadTime ) {
 	if ( mReady ) {
 		if ( loadTime != Time::Zero ) {

src/tools/ecode/plugins/plugin.hpp

@@ -1,6 +1,7 @@
 #ifndef ECODE_PLUGIN_HPP
 #define ECODE_PLUGIN_HPP
 
+#include "../filesystemlisteneroptions.hpp"
 #include "lsp/lspprotocol.hpp"
 #include <eepp/ui/models/filesystemmodel.hpp>
 #include <eepp/ui/uicodeeditor.hpp>
@@ -54,6 +55,8 @@ class Plugin : public UICodeEditorPlugin {
 
 	virtual void onFileSystemEvent( const FileEvent& ev, const FileInfo& file );
 
+	virtual FileSystemListenerOptions getFileSystemListenerOptions() const;
+
 	String i18n( const std::string& key, const String& def ) const;
 
 	UIIcon* findIcon( const std::string& iconName );

src/tools/ecode/plugins/pluginmanager.cpp

@@ -168,6 +168,10 @@ void PluginManager::setWorkspaceFolder( const std::string& workspaceFolder ) {
 	mWorkspaceFolder = workspaceFolder;
 	json data{ { "folder", mWorkspaceFolder } };
 	sendBroadcast( PluginMessageType::WorkspaceFolderChanged, PluginMessageFormat::JSON, &data );
+	// Workspace-scoped plugin filters are snapshots. Re-register after plugins
+	// receive the workspace notification and update their own paths.
+	unsubscribeFileSystemListener();
+	subscribeFileSystemListener();
 }
 
 PluginRequestHandle PluginManager::sendRequest( PluginMessageType type, PluginMessageFormat format,
@@ -295,6 +299,7 @@ void PluginManager::setMainSplitter( UISplitter* splitter ) {
 void PluginManager::setFileSystemListener( FileSystemListener* listener ) {
 	if ( listener == mFileSystemListener )
 		return;
+	unsubscribeFileSystemListener();
 	mFileSystemListener = listener;
 	sendBroadcast( PluginMessageType::FileSystemListenerReady, PluginMessageFormat::Empty,
 				   nullptr );
@@ -302,34 +307,80 @@ void PluginManager::setFileSystemListener( FileSystemListener* listener ) {
 }
 
 void PluginManager::subscribeFileSystemListener( Plugin* plugin ) {
-	Lock l( mPluginsFSSubsMutex );
-	mPluginsFSSubs.insert( plugin );
+	{
+		Lock l( mPluginsFSSubsMutex );
+		if ( !mPluginsFSSubs.insert( plugin ).second )
+			return;
+	}
+	registerFileSystemListener( plugin );
 }
 
 void PluginManager::unsubscribeFileSystemListener( Plugin* plugin ) {
-	Lock l( mPluginsFSSubsMutex );
-	mPluginsFSSubs.erase( plugin );
+	Uint64 listenerId{ 0 };
+	{
+		Lock l( mPluginsFSSubsMutex );
+		mPluginsFSSubs.erase( plugin );
+		auto it = mPluginFSListenerIds.find( plugin );
+		if ( it != mPluginFSListenerIds.end() ) {
+			listenerId = it->second;
+			mPluginFSListenerIds.erase( it );
+		}
+	}
+	if ( listenerId != 0 && mFileSystemListener )
+		mFileSystemListener->removeListener( listenerId );
 }
 
 void PluginManager::subscribeFileSystemListener() {
-	if ( mFileSystemListenerCb != 0 || mFileSystemListener == nullptr )
+	if ( mFileSystemListener == nullptr )
 		return;
-
-	mFileSystemListenerCb =
-		mFileSystemListener->addListener( [this]( const FileEvent& ev, const FileInfo& file ) {
-			UnorderedSet<Plugin*> plugins;
-			{
-				Lock l( mPluginsFSSubsMutex );
-				plugins = mPluginsFSSubs;
-			}
-			for ( Plugin* plugin : plugins )
-				plugin->onFileSystemEvent( ev, file );
-		} );
+	UnorderedSet<Plugin*> plugins;
+	{
+		Lock l( mPluginsFSSubsMutex );
+		plugins = mPluginsFSSubs;
+	}
+	for ( Plugin* plugin : plugins )
+		registerFileSystemListener( plugin );
 }
 
 void PluginManager::unsubscribeFileSystemListener() {
-	if ( mFileSystemListenerCb != 0 && mFileSystemListener )
-		mFileSystemListener->removeListener( mFileSystemListenerCb );
+	std::vector<Uint64> listenerIds;
+	{
+		Lock l( mPluginsFSSubsMutex );
+		listenerIds.reserve( mPluginFSListenerIds.size() );
+		for ( const auto& listener : mPluginFSListenerIds )
+			listenerIds.emplace_back( listener.second );
+		mPluginFSListenerIds.clear();
+	}
+	if ( mFileSystemListener ) {
+		for ( Uint64 listenerId : listenerIds )
+			mFileSystemListener->removeListener( listenerId );
+	}
+}
+
+void PluginManager::registerFileSystemListener( Plugin* plugin ) {
+	if ( mFileSystemListener == nullptr )
+		return;
+	{
+		Lock l( mPluginsFSSubsMutex );
+		if ( mPluginsFSSubs.find( plugin ) == mPluginsFSSubs.end() ||
+			 mPluginFSListenerIds.find( plugin ) != mPluginFSListenerIds.end() )
+			return;
+	}
+	const Uint64 listenerId = mFileSystemListener->addListener(
+		[plugin]( const FileEvent& ev, const FileInfo& file ) {
+			plugin->onFileSystemEvent( ev, file );
+		},
+		plugin->getFileSystemListenerOptions() );
+	bool removeListener{ false };
+	{
+		Lock l( mPluginsFSSubsMutex );
+		if ( mPluginsFSSubs.find( plugin ) != mPluginsFSSubs.end() )
+			mPluginFSListenerIds[plugin] = listenerId;
+		else
+			removeListener = true;
+	}
+	if ( removeListener )
+		mFileSystemListener->removeListener( listenerId );
 }
 
 void PluginManager::sendBroadcast( const PluginMessageType& notification,

src/tools/ecode/plugins/pluginmanager.hpp

@@ -393,8 +393,8 @@ class PluginManager {
 	Mutex mPluginsFSSubsMutex;
 	SubscribedPlugins mSubscribedPlugins;
 	OnLoadFileCb mLoadFileFn;
-	Uint64 mFileSystemListenerCb{ 0 };
 	UnorderedSet<Plugin*> mPluginsFSSubs;
+	UnorderedMap<Plugin*, Uint64> mPluginFSListenerIds;
 	bool mClosing{ false };
 	bool mPluginReloadEnabled{ false };
 	bool mPluginsDisabled{ false };
@@ -410,6 +410,8 @@ class PluginManager {
 	void subscribeFileSystemListener();
 
 	void unsubscribeFileSystemListener();
+
+	void registerFileSystemListener( Plugin* plugin );
 };
 
 class PluginsModel : public Model {

src/tools/ecode/projectdirectorytree.cpp

@@ -245,6 +245,7 @@ std::shared_ptr<FileListModel>
 ProjectDirectoryTree::asModel( const size_t& max, const std::vector<CommandInfo>& prependCommands,
 							   const std::string& basePath,
 							   const std::vector<std::string>& skipExtensions ) const {
+	Lock rl( mMatchingMutex );
 	size_t namesSize = mNames.size();
 	size_t rmax = eemin( namesSize, max );
 	std::vector<std::string> files;
@@ -440,6 +441,7 @@ void ProjectDirectoryTree::tryAddFile( const FileInfo& file ) {
 			}
 		}
 		if ( foundPattern ) {
+			Lock rl( mMatchingMutex );
 			Lock l( mFilesMutex );
 			auto exists =
 				std::find( mFiles.begin(), mFiles.end(), file.getFilepath() ) != mFiles.end();
@@ -457,6 +459,7 @@ void ProjectDirectoryTree::addFile( const FileInfo& file ) {
 			return;
 		if ( mIgnoreHidden && file.isHidden() )
 			return;
+		Lock rl( mMatchingMutex );
 		Lock l( mFilesMutex );
 		std::vector<std::string> files;
 		std::vector<std::string> names;
@@ -490,13 +493,15 @@ void ProjectDirectoryTree::addFile( const FileInfo& file ) {
 }
 
 void ProjectDirectoryTree::moveFile( const FileInfo& file, const std::string& oldFilename ) {
+	Lock rl( mMatchingMutex );
 	Lock l( mFilesMutex );
 	if ( file.isDirectory() ) {
 		std::string dir( file.getDirectoryPath() );
 		FileSystem::dirRemoveSlashAtEnd( dir );
 		std::string parentDir( FileSystem::fileRemoveFileName( dir ) );
 		FileSystem::dirAddSlashAtEnd( parentDir );
-		std::string oldDir( parentDir + oldFilename );
+		std::string oldDir( FileSystem::isRelativePath( oldFilename ) ? parentDir + oldFilename
+																	  : oldFilename );
 		FileSystem::dirAddSlashAtEnd( dir );
 		FileSystem::dirAddSlashAtEnd( oldDir );
 		std::vector<std::string> files;
@@ -525,7 +530,9 @@ void ProjectDirectoryTree::moveFile( const FileInfo& file, const std::string& ol
 	} else {
 		std::string dir( file.getDirectoryPath() );
 		FileSystem::dirAddSlashAtEnd( dir );
-		size_t index = findFileIndex( dir + oldFilename );
+		const std::string oldPath =
+			FileSystem::isRelativePath( oldFilename ) ? dir + oldFilename : oldFilename;
+		size_t index = findFileIndex( oldPath );
 		if ( index != std::string::npos ) {
 			IgnoreMatcherManager matcher( getIgnoreMatcherFromPath( file.getFilepath() ) );
 			if ( !( mIgnoreHidden && file.isHidden() ) &&
@@ -554,19 +561,20 @@ void ProjectDirectoryTree::removeFile( const FileInfo& file ) {
 	}
 
 	if ( wasDir ) {
-		std::vector<std::string> files;
-		std::vector<std::string> names;
-		files.reserve( mFiles.size() );
-		names.reserve( mNames.size() );
-		for ( size_t i = 0; i < mFiles.size(); i++ ) {
-			if ( !String::startsWith( mFiles[i], removedDir ) ) {
-				files.emplace_back( mFiles[i] );
-				names.emplace_back( mNames[i] );
-			}
-		}
-
 		{
+			Lock rl( mMatchingMutex );
 			Lock l( mFilesMutex );
+			std::vector<std::string> files;
+			std::vector<std::string> names;
+			files.reserve( mFiles.size() );
+			names.reserve( mNames.size() );
+			for ( size_t i = 0; i < mFiles.size(); i++ ) {
+				if ( !String::startsWith( mFiles[i], removedDir ) ) {
+					files.emplace_back( mFiles[i] );
+					names.emplace_back( mNames[i] );
+				}
+			}
+
 			mFiles = std::move( files );
 			mNames = std::move( names );
 		}
@@ -574,9 +582,10 @@ void ProjectDirectoryTree::removeFile( const FileInfo& file ) {
 		Lock ld2( mDirectoriesMutex );
 		mDirectories.erase( std::find( mDirectories.begin(), mDirectories.end(), removedDir ) );
 	} else {
+		Lock rl( mMatchingMutex );
+		Lock l( mFilesMutex );
 		size_t index = findFileIndex( file.getFilepath() );
 		if ( index != std::string::npos ) {
-			Lock l( mFilesMutex );
 			mFiles.erase( mFiles.begin() + index );
 			mNames.erase( mNames.begin() + index );
 		}