Storage: keep weak pointer to Storage in head watcher

2 files changed, 13 insertions, 11 deletions

diff --git a/include/erebos/storage.h b/include/erebos/storage.h
index 10ced57..75b8139 100644
--- a/include/erebos/storage.h
+++ b/include/erebos/storage.h
@@ -60,7 +60,7 @@ protected:
 	friend erebos::PartialRef;
 	struct Priv;
 	const std::shared_ptr<const Priv> p;
-	PartialStorage(const std::shared_ptr<const Priv> p): p(p) {}
+	PartialStorage(const std::shared_ptr<const Priv> & p): p(p) {}
 };
 
 class Storage : public PartialStorage
@@ -102,7 +102,7 @@ protected:
 	template<typename T> friend class Head;
 	template<typename T> friend class WatchedHead;
 
-	Storage(const std::shared_ptr<const Priv> p): PartialStorage(p) {}
+	Storage(const std::shared_ptr<const Priv> & p): PartialStorage(p) {}
 
 	std::optional<Ref> headRef(UUID type, UUID id) const;
 	std::vector<std::tuple<UUID, Ref>> headRefs(UUID type) const;
@@ -156,7 +156,7 @@ public:
 	PartialRef & operator=(const PartialRef &) = default;
 	PartialRef & operator=(PartialRef &&) = default;
 
-	static PartialRef create(PartialStorage, const Digest &);
+	static PartialRef create(const PartialStorage &, const Digest &);
 
 	const Digest & digest() const;
 
@@ -184,8 +184,8 @@ public:
 	bool operator==(const Ref &) = delete;
 	bool operator!=(const Ref &) = delete;
 
-	static std::optional<Ref> create(Storage, const Digest &);
-	static Ref zcreate(Storage);
+	static std::optional<Ref> create(const Storage &, const Digest &);
+	static Ref zcreate(const Storage &);
 
 	explicit constexpr operator bool() const { return true; }
 	const Object operator*() const;
diff --git a/src/storage.cpp b/src/storage.cpp
index f50b471..bd0beae 100644
--- a/src/storage.cpp
+++ b/src/storage.cpp
@@ -37,6 +37,7 @@ using std::shared_ptr;
 using std::string;
 using std::system_error;
 using std::to_string;
+using std::weak_ptr;
 
 FilesystemStorage::FilesystemStorage(const fs::path & path):
 	root(path)
@@ -832,10 +833,11 @@ optional<Ref> Storage::updateHead(UUID type, UUID id, const Ref & old, const std
 
 int Storage::watchHead(UUID type, UUID wid, const std::function<void(const Ref &)> watcher) const
 {
-	return p->backend->watchHead(type, [this, wid, watcher] (UUID id, const Digest & dgst) {
+	return p->backend->watchHead(type, [wp = weak_ptr<const Priv>(p), wid, watcher] (UUID id, const Digest & dgst) {
 		if (id == wid)
-			if (auto r = ref(dgst))
-				watcher(*r);
+			if (auto p = wp.lock())
+				if (auto r = Ref::create(Storage(p), dgst))
+					watcher(*r);
 	});
 }
 
@@ -889,7 +891,7 @@ Digest Digest::of(const vector<uint8_t> & content)
 }
 
 
-PartialRef PartialRef::create(PartialStorage st, const Digest & digest)
+PartialRef PartialRef::create(const PartialStorage & st, const Digest & digest)
 {
 	auto p = new Priv {
 		.storage = make_unique<PartialStorage>(st),
@@ -926,7 +928,7 @@ const PartialStorage & PartialRef::storage() const
 	return *p->storage;
 }
 
-optional<Ref> Ref::create(Storage st, const Digest & digest)
+optional<Ref> Ref::create(const Storage & st, const Digest & digest)
 {
 	if (!st.p->backend->contains(digest))
 		return nullopt;
@@ -939,7 +941,7 @@ optional<Ref> Ref::create(Storage st, const Digest & digest)
 	return Ref(shared_ptr<Priv>(p));
 }
 
-Ref Ref::zcreate(Storage st)
+Ref Ref::zcreate(const Storage & st)
 {
 	auto p = new Priv {
 		.storage = make_unique<PartialStorage>(st),