From f34ebec1cfdc489fdb44e5fd3e42ac79c48cfda9 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Fri, 4 May 2018 15:57:50 -0700
Subject: [PATCH] ircd::db: Add convenience read(column) nothrow overloads.

---
 include/ircd/db/column.h |  5 +++++
 ircd/db.cc               | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/ircd/db/column.h b/include/ircd/db/column.h
index 21ec63b48..a5a9d880a 100644
--- a/include/ircd/db/column.h
+++ b/include/ircd/db/column.h
@@ -38,6 +38,11 @@ namespace ircd::db
 	string_view read(column &, const string_view &key, const mutable_buffer &, const gopts & = {});
 	std::string read(column &, const string_view &key, const gopts & = {});
 
+	// [GET] Nothrow convenience functions to copy data into your buffer; since
+	// a key can exist with an empty value we must overload on this bool here.
+	string_view read(column &, const string_view &key, bool &found, const mutable_buffer &, const gopts & = {});
+	std::string read(column &, const string_view &key, bool &found, const gopts & = {});
+
 	// [SET] Write data to the db
 	void write(column &, const string_view &key, const const_buffer &value, const sopts & = {});
 
diff --git a/ircd/db.cc b/ircd/db.cc
index c27acb7a7..a28d7a3f4 100644
--- a/ircd/db.cc
+++ b/ircd/db.cc
@@ -3863,6 +3863,41 @@ ircd::db::read(column &column,
 	return ret;
 }
 
+std::string
+ircd::db::read(column &column,
+               const string_view &key,
+               bool &found,
+               const gopts &gopts)
+{
+	std::string ret;
+	const auto closure([&ret]
+	(const string_view &src)
+	{
+		ret.assign(begin(src), end(src));
+	});
+
+	found = column(key, std::nothrow, closure, gopts);
+	return ret;
+}
+
+ircd::string_view
+ircd::db::read(column &column,
+               const string_view &key,
+               bool &found,
+               const mutable_buffer &buf,
+               const gopts &gopts)
+{
+	string_view ret;
+	const auto closure([&buf, &ret]
+	(const string_view &src)
+	{
+		ret = { data(buf), copy(buf, src) };
+	});
+
+	found = column(key, std::nothrow, closure, gopts);
+	return ret;
+}
+
 template<>
 ircd::db::prop_str
 ircd::db::property(const column &column,