From c3d6046b25ef0786b8d2919dfa9db4eb05114501 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sun, 21 Feb 2021 22:16:21 +0100
Subject: Sync service

---
 src/CMakeLists.txt |  1 +
 src/service.cpp    |  4 +++
 src/state.cpp      | 34 +++++++++++++++++++++---
 src/sync.cpp       | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 113 insertions(+), 3 deletions(-)
 create mode 100644 src/sync.cpp

(limited to 'src')

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index d8a076a..61f491f 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -13,6 +13,7 @@ add_library(erebos
 	service
 	state
 	storage
+	sync
 	time
 	uuid
 )
diff --git a/src/service.cpp b/src/service.cpp
index c731990..14ff665 100644
--- a/src/service.cpp
+++ b/src/service.cpp
@@ -33,3 +33,7 @@ void Service::Context::local(const LocalState & ls)
 {
 	p->local = p->local.ref().storage().store(ls);
 }
+
+void Service::serverStarted(const class Server &)
+{
+}
diff --git a/src/state.cpp b/src/state.cpp
index 8790dfc..6e39b5e 100644
--- a/src/state.cpp
+++ b/src/state.cpp
@@ -78,13 +78,41 @@ vector<Ref> LocalState::lookupShared(UUID type) const
 	return res;
 }
 
+vector<Ref> LocalState::sharedRefs() const
+{
+	vector<Ref> refs;
+	for (const auto & x : p->shared)
+		refs.push_back(x.ref());
+	return refs;
+}
+
+LocalState LocalState::sharedRefAdd(const Ref & ref) const
+{
+	const Storage * st;
+	if (p->shared.size() > 0)
+		st = &p->shared[0].ref().storage();
+	else if (p->identity)
+		st = &p->identity->ref()->storage();
+	else
+		st = &ref.storage();
+
+	LocalState ret;
+	ret.p->identity = p->identity;
+	ret.p->shared = p->shared;
+	ret.p->shared.push_back(SharedState(ref).store(*st));
+	filterAncestors(ret.p->shared);
+	return ret;
+}
+
 LocalState LocalState::updateShared(UUID type, const vector<Ref> & xs) const
 {
 	const Storage * st;
-	if (xs.size() > 0)
-		st = &xs[0].storage();
-	else if (p->shared.size() > 0)
+	if (p->shared.size() > 0)
 		st = &p->shared[0].ref().storage();
+	else if (p->identity)
+		st = &p->identity->ref()->storage();
+	else if (xs.size() > 0)
+		st = &xs[0].storage();
 	else
 		return *this;
 
diff --git a/src/sync.cpp b/src/sync.cpp
new file mode 100644
index 0000000..37f7ca9
--- /dev/null
+++ b/src/sync.cpp
@@ -0,0 +1,77 @@
+#include <erebos/sync.h>
+
+#include <erebos/network.h>
+
+using namespace erebos;
+
+using std::scoped_lock;
+
+static const UUID myUUID("a4f538d0-4e50-4082-8e10-7e3ec2af175d");
+
+SyncService::SyncService() = default;
+SyncService::~SyncService() = default;
+
+UUID SyncService::uuid() const
+{
+	return myUUID;
+}
+
+void SyncService::handle(Context & ctx)
+{
+	auto pid = ctx.peer().identity();
+	if (!pid)
+		return;
+
+	const auto & powner = pid->finalOwner();
+	const auto & owner = ctx.peer().server().identity().finalOwner();
+
+	if (!powner.sameAs(owner))
+		return;
+
+	ctx.local(
+		ctx.local()->sharedRefAdd(ctx.ref())
+	);
+}
+
+void SyncService::serverStarted(const Server & s)
+{
+	server = &s;
+	server->peerList().onUpdate(std::bind(&SyncService::peerWatcher, this,
+				std::placeholders::_1, std::placeholders::_2));
+	watchedHead = server->localHead().watch(std::bind(&SyncService::localStateWatcher, this,
+				std::placeholders::_1));
+}
+
+void SyncService::peerWatcher(size_t, const Peer * peer)
+{
+	if (peer && peer->identity()->finalOwner().sameAs(
+				server->identity().finalOwner())) {
+		scoped_lock lock(headMutex);
+		for (const auto & r : (*watchedHead)->sharedRefs())
+			peer->send(myUUID, r);
+	}
+}
+
+void SyncService::localStateWatcher(const Head<LocalState> & head)
+{
+	scoped_lock lock(headMutex);
+
+	bool same = head->sharedRefs().size() ==
+		(*watchedHead)->sharedRefs().size();
+	if (same) {
+		for (size_t i = 0; i < head->sharedRefs().size(); i++)
+			if (head->sharedRefs()[i].digest() !=
+					(*watchedHead)->sharedRefs()[i].digest()) {
+				same = false;
+				break;
+			}
+	}
+
+	if (!same) {
+		*watchedHead = head;
+		const auto & plist = server->peerList();
+		for (size_t i = 0; i < plist.size(); i++)
+			for (const auto & r : (*watchedHead)->sharedRefs())
+				plist.at(i).send(myUUID, r);
+	}
+}
-- 
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