From 11df089f3000bb8e402583b26a636897f4c58d9d Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Thu, 17 May 2018 19:29:44 -0700
Subject: [PATCH] modules/s_state: Preliminary tree rebuild from forward
 iteration; console cmd.

---
 modules/console.cc | 33 ++++++++++++++++++++
 modules/s_state.cc | 77 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)

diff --git a/modules/console.cc b/modules/console.cc
index 6b9f8761e..6ccbfeb41 100644
--- a/modules/console.cc
+++ b/modules/console.cc
@@ -3195,6 +3195,39 @@ console_cmd__room__state__rebuild__present(opt &out, const string_view &line)
 	return true;
 }
 
+bool
+console_cmd__room__state__rebuild__history(opt &out, const string_view &line)
+{
+	const params param{line, " ",
+	{
+		"room_id"
+	}};
+
+	const auto &room_id
+	{
+		m::room_id(param.at(0))
+	};
+
+	const m::room room
+	{
+		room_id
+	};
+
+	using prototype = size_t (const m::room &);
+	static m::import<prototype> state__rebuild_history
+	{
+		"s_state", "state__rebuild_history"
+	};
+
+	const size_t count
+	{
+		state__rebuild_history(room)
+	};
+
+	out << "done " << count << std::endl;
+	return true;
+}
+
 bool
 console_cmd__room__count(opt &out, const string_view &line)
 {
diff --git a/modules/s_state.cc b/modules/s_state.cc
index 9deb8205d..db3bcbb13 100644
--- a/modules/s_state.cc
+++ b/modules/s_state.cc
@@ -64,3 +64,80 @@ state__rebuild_present(const m::room &room)
 	txn();
 	return ret;
 }
+
+extern "C" size_t
+state__rebuild_history(const m::room &room)
+{
+	size_t ret{0};
+	const m::room::state state
+	{
+		room
+	};
+
+	const auto create_id
+	{
+		state.get("m.room.create")
+	};
+
+	m::room::messages it
+	{
+		room, create_id
+	};
+
+	if(!it)
+		return ret;
+
+	db::txn txn
+	{
+		*m::dbs::events
+	};
+
+	uint r(0);
+	char root[2][64] {0};
+	m::dbs::write_opts opts;
+	opts.root_in = root[++r % 2];
+	opts.root_out = root[++r % 2];
+	opts.present = false;
+	opts.history = true;
+	opts.head = false;
+	opts.refs = false;
+
+	int64_t depth{0};
+	for(; it; ++it)
+	{
+		const m::event &event{*it};
+		opts.idx = it.event_idx();
+		if(at<"depth"_>(event) == depth + 1)
+			++depth;
+
+		if(at<"depth"_>(event) != depth)
+			throw ircd::error
+			{
+				"Incomplete room history: gap between %ld and %ld [%s]",
+				depth,
+				at<"depth"_>(event),
+				string_view{at<"event_id"_>(event)}
+			};
+
+		if(at<"type"_>(event) == "m.room.redaction")
+		{
+			opts.root_in = m::dbs::_index_redact(txn, event, opts);
+			opts.root_out = root[++r % 2];
+			txn();
+			txn.clear();
+		}
+		else if(defined(json::get<"state_key"_>(event)))
+		{
+			opts.root_in = m::dbs::_index_state(txn, event, opts);
+			opts.root_out = root[++r % 2];
+			txn();
+			txn.clear();
+		}
+		else m::dbs::_index_ephem(txn, event, opts);
+
+		++ret;
+	}
+
+	txn();
+	return ret;
+}