6 files changed, 160 insertions, 17 deletions

diff --git a/src/db/update/Container.cxx b/src/db/update/Container.cxx
index 9f8d84839..1c420fa99 100644
--- a/src/db/update/Container.cxx
+++ b/src/db/update/Container.cxx
@@ -42,6 +42,9 @@ UpdateWalk::MakeDirectoryIfModified(Directory &parent, const char *name,
 
 	// directory exists already
 	if (directory != nullptr) {
+		if (directory->IsMount())
+			return nullptr;
+
 		if (directory->mtime == info.mtime && !walk_discard) {
 			/* not modified */
 			return nullptr;
diff --git a/src/db/update/Queue.cxx b/src/db/update/Queue.cxx
index 096a39a8c..6d6d80131 100644
--- a/src/db/update/Queue.cxx
+++ b/src/db/update/Queue.cxx
@@ -21,12 +21,13 @@
 #include "Queue.hxx"
 
 bool
-UpdateQueue::Push(const char *path, bool discard, unsigned id)
+UpdateQueue::Push(SimpleDatabase &db, Storage &storage,
+		  const char *path, bool discard, unsigned id)
 {
 	if (update_queue.size() >= MAX_UPDATE_QUEUE_SIZE)
 		return false;
 
-	update_queue.emplace_back(path, discard, id);
+	update_queue.emplace_back(db, storage, path, discard, id);
 	return true;
 }
 
@@ -40,3 +41,27 @@ UpdateQueue::Pop()
 	update_queue.pop_front();
 	return i;
 }
+
+void
+UpdateQueue::Erase(SimpleDatabase &db)
+{
+	for (auto i = update_queue.begin(), end = update_queue.end();
+	     i != end;) {
+		if (i->db == &db)
+			i = update_queue.erase(i);
+		else
+			++i;
+	}
+}
+
+void
+UpdateQueue::Erase(Storage &storage)
+{
+	for (auto i = update_queue.begin(), end = update_queue.end();
+	     i != end;) {
+		if (i->storage == &storage)
+			i = update_queue.erase(i);
+		else
+			++i;
+	}
+}
diff --git a/src/db/update/Queue.hxx b/src/db/update/Queue.hxx
index 039c62fe3..9064ea481 100644
--- a/src/db/update/Queue.hxx
+++ b/src/db/update/Queue.hxx
@@ -21,19 +21,30 @@
 #define MPD_UPDATE_QUEUE_HXX
 
 #include "check.h"
+#include "Compiler.h"
 
 #include <string>
 #include <list>
 
+class SimpleDatabase;
+class Storage;
+
 struct UpdateQueueItem {
+	SimpleDatabase *db;
+	Storage *storage;
+
 	std::string path_utf8;
 	unsigned id;
 	bool discard;
 
 	UpdateQueueItem():id(0) {}
-	UpdateQueueItem(const char *_path, bool _discard,
+
+	UpdateQueueItem(SimpleDatabase &_db,
+			Storage &_storage,
+			const char *_path, bool _discard,
 			unsigned _id)
-		:path_utf8(_path), id(_id), discard(_discard) {}
+		:db(&_db), storage(&_storage), path_utf8(_path),
+		 id(_id), discard(_discard) {}
 
 	bool IsDefined() const {
 		return id != 0;
@@ -46,13 +57,21 @@ class UpdateQueue {
 	std::list<UpdateQueueItem> update_queue;
 
 public:
-	bool Push(const char *path, bool discard, unsigned id);
+	gcc_nonnull_all
+	bool Push(SimpleDatabase &db, Storage &storage,
+		  const char *path, bool discard, unsigned id);
 
 	UpdateQueueItem Pop();
 
 	void Clear() {
 		update_queue.clear();
 	}
+
+	gcc_nonnull_all
+	void Erase(SimpleDatabase &db);
+
+	gcc_nonnull_all
+	void Erase(Storage &storage);
 };
 
 #endif
diff --git a/src/db/update/Service.cxx b/src/db/update/Service.cxx
index 2971998e4..e8a1f6b02 100644
--- a/src/db/update/Service.cxx
+++ b/src/db/update/Service.cxx
@@ -22,7 +22,10 @@
 #include "Walk.hxx"
 #include "UpdateDomain.hxx"
 #include "db/DatabaseListener.hxx"
+#include "db/DatabaseLock.hxx"
 #include "db/plugins/simple/SimpleDatabasePlugin.hxx"
+#include "db/plugins/simple/Directory.hxx"
+#include "storage/CompositeStorage.hxx"
 #include "Idle.hxx"
 #include "util/Error.hxx"
 #include "Log.hxx"
@@ -39,7 +42,7 @@
 #include <assert.h>
 
 UpdateService::UpdateService(EventLoop &_loop, SimpleDatabase &_db,
-			     Storage &_storage,
+			     CompositeStorage &_storage,
 			     DatabaseListener &_listener)
 	:DeferredMonitor(_loop),
 	 db(_db), storage(_storage),
@@ -71,6 +74,42 @@ UpdateService::CancelAllAsync()
 		walk->Cancel();
 }
 
+void
+UpdateService::CancelMount(const char *uri)
+{
+	/* determine which (mounted) database will be updated and what
+	   storage will be scanned */
+
+	db_lock();
+	const auto lr = db.GetRoot().LookupDirectory(uri);
+	db_unlock();
+
+	if (!lr.directory->IsMount())
+		return;
+
+	bool cancel_current = false;
+
+	Storage *storage2 = storage.GetMount(uri);
+	if (storage2 != nullptr) {
+		queue.Erase(*storage2);
+		cancel_current = next.IsDefined() && next.storage == storage2;
+	}
+
+	Database &_db2 = *lr.directory->mounted_database;
+	if (_db2.IsPlugin(simple_db_plugin)) {
+		SimpleDatabase &db2 = static_cast<SimpleDatabase &>(_db2);
+		queue.Erase(db2);
+		cancel_current |= next.IsDefined() && next.db == &db2;
+	}
+
+	if (cancel_current && walk != nullptr) {
+		walk->Cancel();
+
+		if (update_thread.IsDefined())
+			update_thread.Join();
+	}
+}
+
 inline void
 UpdateService::Task()
 {
@@ -84,12 +123,12 @@ UpdateService::Task()
 
 	SetThreadIdlePriority();
 
-	modified = walk->Walk(db.GetRoot(), next.path_utf8.c_str(),
+	modified = walk->Walk(next.db->GetRoot(), next.path_utf8.c_str(),
 			      next.discard);
 
-	if (modified || !db.FileExists()) {
+	if (modified || !next.db->FileExists()) {
 		Error error;
-		if (!db.Save(error))
+		if (!next.db->Save(error))
 			LogError(error, "Failed to save database");
 	}
 
@@ -120,7 +159,7 @@ UpdateService::StartThread(UpdateQueueItem &&i)
 	modified = false;
 
 	next = std::move(i);
-	walk = new UpdateWalk(GetEventLoop(), listener, storage);
+	walk = new UpdateWalk(GetEventLoop(), listener, *next.storage);
 
 	Error error;
 	if (!update_thread.Start(Task, this, error))
@@ -144,9 +183,52 @@ UpdateService::Enqueue(const char *path, bool discard)
 {
 	assert(GetEventLoop().IsInsideOrNull());
 
+	/* determine which (mounted) database will be updated and what
+	   storage will be scanned */
+	SimpleDatabase *db2;
+	Storage *storage2;
+
+	db_lock();
+	const auto lr = db.GetRoot().LookupDirectory(path);
+	db_unlock();
+	if (lr.directory->IsMount()) {
+		/* follow the mountpoint, update the mounted
+		   database */
+
+		Database &_db2 = *lr.directory->mounted_database;
+		if (!_db2.IsPlugin(simple_db_plugin))
+			/* cannot update this type of database */
+			return 0;
+
+		db2 = static_cast<SimpleDatabase *>(&_db2);
+
+		if (lr.uri == nullptr) {
+			storage2 = storage.GetMount(path);
+			path = "";
+		} else {
+			assert(lr.uri > path);
+			assert(lr.uri < path + strlen(path));
+			assert(lr.uri[-1] == '/');
+
+			const std::string mountpoint(path, lr.uri - 1);
+			storage2 = storage.GetMount(mountpoint.c_str());
+			path = lr.uri;
+		}
+	} else {
+		/* use the "root" database/storage */
+
+		db2 = &db;
+		storage2 = storage.GetMount("");
+	}
+
+	if (storage2 == nullptr)
+		/* no storage found at this mount point - should not
+		   happen */
+		return 0;
+
 	if (progress != UPDATE_PROGRESS_IDLE) {
 		const unsigned id = GenerateId();
-		if (!queue.Push(path, discard, id))
+		if (!queue.Push(*db2, *storage2, path, discard, id))
 			return 0;
 
 		update_task_id = id;
@@ -154,7 +236,7 @@ UpdateService::Enqueue(const char *path, bool discard)
 	}
 
 	const unsigned id = update_task_id = GenerateId();
-	StartThread(UpdateQueueItem(path, discard, id));
+	StartThread(UpdateQueueItem(*db2, *storage2, path, discard, id));
 
 	idle_add(IDLE_UPDATE);
 
@@ -171,7 +253,10 @@ UpdateService::RunDeferred()
 	assert(next.IsDefined());
 	assert(walk != nullptr);
 
-	update_thread.Join();
+	/* wait for thread to finish only if it wasn't cancelled by
+	   CancelMount() */
+	if (update_thread.IsDefined())
+		update_thread.Join();
 
 	delete walk;
 	walk = nullptr;
diff --git a/src/db/update/Service.hxx b/src/db/update/Service.hxx
index e42a0fa5a..cbb4a3f9d 100644
--- a/src/db/update/Service.hxx
+++ b/src/db/update/Service.hxx
@@ -28,7 +28,7 @@
 class SimpleDatabase;
 class DatabaseListener;
 class UpdateWalk;
-class Storage;
+class CompositeStorage;
 
 /**
  * This class manages the update queue and runs the update thread.
@@ -41,7 +41,7 @@ class UpdateService final : DeferredMonitor {
 	};
 
 	SimpleDatabase &db;
-	Storage &storage;
+	CompositeStorage &storage;
 
 	DatabaseListener &listener;
 
@@ -63,7 +63,7 @@ class UpdateService final : DeferredMonitor {
 
 public:
 	UpdateService(EventLoop &_loop, SimpleDatabase &_db,
-		      Storage &_storage,
+		      CompositeStorage &_storage,
 		      DatabaseListener &_listener);
 
 	~UpdateService();
@@ -92,6 +92,13 @@ public:
 	 */
 	void CancelAllAsync();
 
+	/**
+	 * Cancel all updates for the given mount point.  If an update
+	 * is already running for it, the method will wait for
+	 * cancellation to complete.
+	 */
+	void CancelMount(const char *uri);
+
 private:
 	/* virtual methods from class DeferredMonitor */
 	virtual void RunDeferred() override;
diff --git a/src/db/update/Walk.cxx b/src/db/update/Walk.cxx
index 201030f25..c329865ff 100644
--- a/src/db/update/Walk.cxx
+++ b/src/db/update/Walk.cxx
@@ -397,8 +397,12 @@ UpdateWalk::DirectoryMakeChildChecked(Directory &parent,
 	Directory *directory = parent.FindChild(name_utf8);
 	db_unlock();
 
-	if (directory != nullptr)
+	if (directory != nullptr) {
+		if (directory->IsMount())
+			directory = nullptr;
+
 		return directory;
+	}
 
 	FileInfo info;
 	if (!GetInfo(storage, uri_utf8, info) ||