From 57079c0276e3f1f82883fbd2e70c2472d94d3dff Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 31 Dec 2018 11:06:18 -0800
Subject: [PATCH] ircd::http: Add more functionality to headers class.

---
 include/ircd/http.h |  16 +++++-
 ircd/http.cc        | 123 +++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 125 insertions(+), 14 deletions(-)

diff --git a/include/ircd/http.h b/include/ircd/http.h
index 6e827e8c4..2318aac55 100644
--- a/include/ircd/http.h
+++ b/include/ircd/http.h
@@ -30,11 +30,12 @@ namespace ircd::http
 	void writeline(window_buffer &, const window_buffer::closure &);
 	void write(window_buffer &, const header &);
 	void write(window_buffer &, const vector_view<const header> &);
-	bool has(const vector_view<const header> &, const string_view &key);
 	size_t serialized(const vector_view<const header> &);
 	std::string strung(const vector_view<const header> &);
 	void writechunk(window_buffer &, const uint32_t &size);
 	const_buffer writechunk(const mutable_buffer &, const uint32_t &size);
+	bool has(const headers &, const string_view &key);
+	bool has(const vector_view<const header> &, const string_view &key);
 }
 
 /// Root exception for HTTP.
@@ -158,6 +159,7 @@ struct ircd::http::header
 {
 	bool operator<(const string_view &s) const   { return iless(first, s);                         }
 	bool operator==(const string_view &s) const  { return iequals(first, s);                       }
+	bool operator!=(const string_view &s) const  { return !operator==(s);                          }
 
 	using std::pair<string_view, string_view>::pair;
 	header(const line &);
@@ -174,8 +176,20 @@ struct ircd::http::headers
 :string_view
 {
 	using closure = std::function<void (const header &)>;
+	using closure_bool = std::function<bool (const header &)>;
 
+	bool for_each(const closure_bool &) const;
+	string_view operator[](const string_view &key) const;
+	string_view at(const string_view &key) const;
+	bool has(const string_view &key) const;
+
+	using string_view::string_view;
+	headers(parse::capstan &, closure_bool);
 	headers(parse::capstan &, const closure & = {});
+	headers() = default;
+
+	friend bool has(const headers &, const string_view &key);
+	friend bool has(const vector_view<const header> &, const string_view &key);
 };
 
 /// HTTP request suite. Functionality to send and receive requests.
diff --git a/ircd/http.cc b/ircd/http.cc
index da8d4143d..a917dc1e9 100644
--- a/ircd/http.cc
+++ b/ircd/http.cc
@@ -428,22 +428,130 @@ catch(const qi::expectation_failure<const char *> &e)
 	throw_error(e, true);
 }
 
+//
+// headers
+//
+
+bool
+ircd::http::has(const vector_view<const header> &headers,
+                const string_view &key)
+{
+	return end(headers) != std::find_if(begin(headers), end(headers), [&key]
+	(const header &header)
+	{
+		return header == key;
+	});
+}
+
+bool
+ircd::http::has(const headers &headers,
+                const string_view &key)
+{
+	return headers.has(key);
+}
+
+//
+// headers::headers
+//
+
 ircd::http::headers::headers(parse::capstan &pc,
                              const closure &c)
+:headers
+{
+	pc, closure_bool{[&c](const auto &header)
+	{
+		if(c)
+			c(header);
+
+		return true;
+	}}
+}
+{
+}
+
+ircd::http::headers::headers(parse::capstan &pc,
+                             closure_bool c)
 :string_view{[&pc, &c]
 () -> string_view
 {
 	header h{pc};
 	const char *const &started{h.first.data()}, *stopped{started};
 	for(; !h.first.empty(); stopped = h.second.data() + h.second.size(), h = header{pc})
-		if(c)
-			c(h);
+		if(c && !c(h))
+			c = {};
 
 	return { started, stopped };
 }()}
 {
 }
 
+bool
+ircd::http::headers::has(const string_view &key)
+const
+{
+	// has header if break early from for_each
+	return !for_each([&key]
+	(const header &header)
+	{
+		// true to continue; false to break (for_each protocol)
+		return header != key;
+	});
+}
+
+ircd::string_view
+ircd::http::headers::at(const string_view &key)
+const
+{
+	const string_view ret
+	{
+		this->operator[](key)
+	};
+
+	if(unlikely(!ret))
+		throw std::out_of_range{key};
+
+	return ret;
+}
+
+ircd::string_view
+ircd::http::headers::operator[](const string_view &key)
+const
+{
+	string_view ret;
+	for_each([&key, &ret](const auto &header)
+	{
+		if(header == key)
+		{
+			ret = header.second;
+			return false;
+		}
+		else return true;
+	});
+
+	return ret;
+}
+
+bool
+ircd::http::headers::for_each(const closure_bool &closure)
+const
+{
+	if(empty())
+		return true;
+
+	parse::buffer pb{const_buffer{*this}};
+	parse::capstan pc{pb};
+	header h{pc};
+	for(; !h.first.empty(); h = header{pc})
+		if(!closure(h))
+			return false;
+
+	return true;
+}
+
+//
+// header
+//
+
 ircd::http::header::header(const line &line)
 try
 {
@@ -617,17 +725,6 @@ ircd::http::writechunk(window_buffer &buf,
 	});
 }
 
-bool
-ircd::http::has(const vector_view<const header> &headers,
-                const string_view &key)
-{
-	return end(headers) != std::find_if(begin(headers), end(headers), [&key]
-	(const header &header)
-	{
-		return iequals(header.first, key);
-	});
-}
-
 std::string
 ircd::http::strung(const vector_view<const header> &headers)
 {