From b320d8ece1b2fc78982409e8972564cb7413ac33 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 16 Apr 2018 14:21:54 -0700
Subject: [PATCH] ircd::m::vm: Integrate sequence counting.

---
 include/ircd/m/m.h  |   1 +
 include/ircd/m/vm.h |  11 ++++-
 ircd/m/vm.cc        | 114 +++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 119 insertions(+), 7 deletions(-)

diff --git a/include/ircd/m/m.h b/include/ircd/m/m.h
index eb43e575c..4a8f88177 100644
--- a/include/ircd/m/m.h
+++ b/include/ircd/m/m.h
@@ -85,6 +85,7 @@ struct ircd::m::init
 	json::object config;
 	keys::init _keys;
 	dbs::init _dbs;
+	vm::init _vm;
 	std::unique_ptr<modules> modules;
 	std::unique_ptr<listeners> listeners;
 
diff --git a/include/ircd/m/vm.h b/include/ircd/m/vm.h
index e61ed41da..a87c8d3b0 100644
--- a/include/ircd/m/vm.h
+++ b/include/ircd/m/vm.h
@@ -15,11 +15,12 @@
 ///
 namespace ircd::m::vm
 {
-	enum fault :uint;
+	struct init;
 	struct error; // custom exception
 	struct opts;
 	struct eval;
 	struct accepted;
+	enum fault :uint;
 
 	using fault_t = std::underlying_type<fault>::type;
 	using closure = std::function<void (const event &)>;
@@ -29,8 +30,16 @@ namespace ircd::m::vm
 	extern uint64_t current_sequence;
 	extern ctx::shared_view<accepted> accept;
 	extern const opts default_opts;
+
+	uint64_t sequence(const eval &);
 }
 
+struct ircd::m::vm::init
+{
+	init();
+	~init() noexcept;
+};
+
 /// Event Evaluation Device
 ///
 /// This object conducts the evaluation of an event or a tape of multiple
diff --git a/ircd/m/vm.cc b/ircd/m/vm.cc
index 2d442feb4..8edd4fada 100644
--- a/ircd/m/vm.cc
+++ b/ircd/m/vm.cc
@@ -10,6 +10,12 @@
 
 #include <ircd/m/m.h>
 
+namespace ircd::m::vm
+{
+	uint64_t last_sequence(id::event::buf &);
+	uint64_t last_sequence();
+}
+
 decltype(ircd::m::vm::log)
 ircd::m::vm::log
 {
@@ -32,6 +38,37 @@ decltype(ircd::m::vm::default_commit_opts)
 ircd::m::vm::default_commit_opts
 {};
 
+//
+// init
+//
+
+ircd::m::vm::init::init()
+{
+	id::event::buf event_id;
+	current_sequence = last_sequence(event_id);
+
+	log.info("Initializing from vm sequence %lu [%s]",
+	         current_sequence,
+	         current_sequence? string_view{event_id} : "NO EVENTS"_sv);
+}
+
+ircd::m::vm::init::~init()
+{
+	id::event::buf event_id;
+	const auto current_sequence
+	{
+		last_sequence(event_id)
+	};
+
+	log.info("Shutting down @ %lu [%s]",
+	         current_sequence,
+	         current_sequence? string_view{event_id} : "NO EVENTS"_sv);
+}
+
+//
+// commit
+//
+
 /// This function takes an event object vector and adds our origin and event_id
 /// and hashes and signature and attempts to inject the event into the core.
 ///
@@ -164,7 +201,7 @@ ircd::m::vm::commit(const event &event,
                     const opts::commit &opts)
 {
 	if(opts.debuglog_precommit)
-		log.debug("injecting event(mark: %ld) %s",
+		log.debug("injecting event(mark +%ld) %s",
 		          vm::current_sequence,
 		          pretty_oneline(event));
 
@@ -189,9 +226,10 @@ ircd::m::vm::commit(const event &event,
 		eval(event)
 	};
 
-	if(opts.infolog_postcommit)
-		log.info("@%lu %s",
-		         vm::current_sequence,
+	if(opts_.infolog_postcommit)
+		log.info("%s @%lu %s",
+		         reflect(ret),
+		         sequence(eval),
 		         pretty_oneline(event, false));
 
 	return ret;
@@ -395,6 +433,22 @@ ircd::m::vm::_eval_pdu(eval &eval,
 				"Signature verification failed"
 			};
 
+	// Obtain sequence number here
+	const uint64_t sequence_number
+	{
+		++vm::current_sequence
+	};
+
+	db::txn::append
+	{
+		eval.txn, dbs::event_seq,
+		{
+			db::op::SET,
+			byte_view<string_view>(sequence_number),
+			event_id
+		}
+	};
+
 	eval_hook(event);
 
 	const auto &depth
@@ -480,8 +534,56 @@ ircd::m::vm::write(eval &eval)
 		          eval.txn.bytes());
 
 	eval.txn();
-	vm::current_sequence++;
-	eval.txn.clear();
+}
+
+uint64_t
+ircd::m::vm::sequence(const eval &eval)
+{
+	uint64_t ret;
+	eval.txn.at(db::op::SET, "_event_seq", [&ret]
+	(const auto &delta)
+	{
+		const byte_view<uint64_t> seqnum
+		{
+			std::get<delta.KEY>(delta)
+		};
+
+		ret = seqnum;
+	});
+
+	return ret;
+}
+
+uint64_t
+ircd::m::vm::last_sequence()
+{
+	id::event::buf event_id;
+	return last_sequence(event_id);
+}
+
+uint64_t
+ircd::m::vm::last_sequence(id::event::buf &event_id)
+{
+	auto &column
+	{
+		dbs::event_seq
+	};
+
+	const auto it
+	{
+		column.rbegin()
+	};
+
+	if(!it)
+	{
+		// If this iterator is invalid the events db should
+		// be completely fresh.
+		assert(db::sequence(*dbs::events) == 0);
+		return 0;
+	}
+
+	event_id = it->second;
+	return byte_view<uint64_t>(it->first);
 }
 
 ircd::string_view