From 2a2a8bcf86302ead0c06d7ea67467aa10c31d29f Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 3 Dec 2018 17:34:43 -0800
Subject: [PATCH] modules/m_state: Checkpoint preliminary GC util.

---
 modules/console.cc | 18 +++++++++++++++
 modules/m_state.cc | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/modules/console.cc b/modules/console.cc
index d76f5bcad..c1844cb7b 100644
--- a/modules/console.cc
+++ b/modules/console.cc
@@ -5279,6 +5279,24 @@ console_cmd__state__root(opt &out, const string_view &line)
 	return true;
 }
 
+bool
+console_cmd__state__gc(opt &out, const string_view &line)
+{
+	using prototype = size_t ();
+	static mods::import<prototype> gc
+	{
+		"m_state", "ircd__m__state__gc"
+	};
+
+	const size_t count
+	{
+		gc()
+	};
+
+	out << "done: " << count << std::endl;
+	return true;
+}
+
 //
 // commit
 //
diff --git a/modules/m_state.cc b/modules/m_state.cc
index b0b6112c4..b62c476cf 100644
--- a/modules/m_state.cc
+++ b/modules/m_state.cc
@@ -15,3 +15,60 @@ IRCD_MODULE
 {
 	"Matrix state library; modular components."
 };
+
+namespace ircd::m::state
+{
+	extern "C" size_t ircd__m__state__gc(void);
+}
+
+size_t
+ircd::m::state::ircd__m__state__gc()
+{
+	std::set<id_buffer> heads;
+	{
+		const db::gopts opts{db::get::NO_CACHE};
+		//opts.readahead = 4_MiB;
+
+		db::column &column{m::dbs::room_events};
+		for(auto it(column.begin(opts)); it; ++it)
+		{
+			const auto &root(it->second);
+			id_buffer buf;
+			copy(buf, root);
+			heads.emplace(buf);
+		}
+	}
+
+	std::set<id_buffer> active;
+	for(auto it(begin(heads)); it != end(heads); it = heads.erase(it))
+	{
+		const auto &root(*it);
+		std::cout << "root: " << string_view{root} << std::endl;
+		state::for_each(root, state::iter_bool_closure{[&active]
+		(const json::array &key, const string_view &val)
+		{
+			std::cout << "key: " << key << std::endl;
+			std::cout << "val: " << val << std::endl;
+			return true;
+		}});
+
+		break;
+	}
+/*
+	static const db::gopts opts
+	{
+		db::get::NO_CACHE
+	};
+
+	auto &column{m::dbs::state_node};
+	for(auto it(column.begin(opts)); it; ++it)
+	{
+		id_buffer buf;
+		const auto &root(it->second);
+		copy(buf, root);
+		active.emplace(buf);
+	}
+*/
+	size_t ret(active.size());
+	return ret;
+}