From b927b7a05dfa87886badcb413743bc06111edac1 Mon Sep 17 00:00:00 2001
From: Doralitze <doralitze@chaotikum.org>
Date: Tue, 5 Jan 2021 21:58:48 +0100
Subject: [PATCH] add: connection_line_buffer class
TODO: Write unit test for connection_line_buffer using loopback client.
Warning: Do not rely on connection_line_buffer::conn_data_in_cb until the unit test case proves its correctness (Nice looking solution but kinda smells like an off-by-one)
---
src/net/connection_line_buffer.cpp | 74 ++++++++++++++++++++++++++++++
src/net/connection_line_buffer.hpp | 38 +++++++++++++++
2 files changed, 112 insertions(+)
create mode 100644 src/net/connection_line_buffer.cpp
create mode 100644 src/net/connection_line_buffer.hpp
diff --git a/src/net/connection_line_buffer.cpp b/src/net/connection_line_buffer.cpp
new file mode 100644
index 0000000..7d1c562
--- /dev/null
+++ b/src/net/connection_line_buffer.cpp
@@ -0,0 +1,74 @@
+/*
+ * connection_line_buffer.cpp
+ *
+ * Created on: 05.01.2021
+ * Author: doralitze
+ */
+
+#include "net/connection_line_buffer.hpp"
+
+namespace rmrf::net {
+
+static std::string::size_type default_eol_search(const std::string& data, std::string::size_type start_position) {
+ const std::string::size_type s = data.size();
+ for (std::string::size_type i = start_position; i < s; i++) {
+ switch (data[i]) {
+ case '\r':
+ if(i < s - 1) {
+ if (data[i + 1] == '\n') {
+ i++;
+ }
+ }
+ [[fallthrough]];
+ case '\n':
+ return i;
+ break;
+ default:
+ break;
+ }
+ }
+ return std::string::npos;
+}
+
+connection_line_buffer::connection_line_buffer(std::shared_ptr<connection_client> c, found_next_line_cb_t found_next_line_cb_,
+ std::string::size_type max_line_size, eol_search_t search_lb) :
+ search(search_lb),
+ client(c),
+ found_next_line_cb(found_next_line_cb_),
+ max(max_line_size),
+ data("") {
+ this->client->set_incomming_data_callback(std::bind(&connection_line_buffer::conn_data_in_cb, this, std::placeholders::_1));
+}
+
+connection_line_buffer::connection_line_buffer(std::shared_ptr<connection_client> c, found_next_line_cb_t found_next_line_cb_,
+ std::string::size_type max_line_size) : connection_line_buffer{c, found_next_line_cb_, max_line_size, &default_eol_search} { }
+
+void connection_line_buffer::conn_data_in_cb(const std::string& data_in) {
+
+ /**
+ * Known limitation: If the last received data ends with '\r' and the next incoming data would start with '\n' there is no way
+ * to detect this as the received message might indeed be a complete one ending with '\r' and one cannot wait for a potential
+ * continuation of said message to arrive.
+ */
+
+ std::string::size_type strpos = 0;
+
+ while(strpos != std::string::npos) {
+ std::string::size_type nextpos = this->search(data_in, strpos);
+ if (nextpos == std::string::npos) {
+ this->data += data_in.substr(strpos, data_in.length() - strpos);
+ break;
+ } else {
+ this->found_next_line_cb(this->data + data_in.substr(strpos, nextpos - strpos), true);
+ this->data = std::string("");
+ }
+ strpos = nextpos;
+ }
+
+ if (this->data.length() > this->max) {
+ this->found_next_line_cb(this->data, false);
+ this->data = std::string("");
+ }
+}
+
+}
diff --git a/src/net/connection_line_buffer.hpp b/src/net/connection_line_buffer.hpp
new file mode 100644
index 0000000..6eaf17c
--- /dev/null
+++ b/src/net/connection_line_buffer.hpp
@@ -0,0 +1,38 @@
+/*
+ * connection_line_buffer.hpp
+ *
+ * Created on: 05.01.2021
+ * Author: doralitze
+ */
+
+#pragma once
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include "net/connection_client.hpp"
+
+namespace rmrf::net {
+
+typedef std::function<std::string::size_type(const std::string&, std::string::size_type)> eol_search_t;
+
+static std::string::size_type default_eol_search(const std::string& data, std::string::size_type start_position);
+
+class connection_line_buffer {
+public:
+ typedef std::function<void(const std::string&, bool)> found_next_line_cb_t;
+private:
+ const eol_search_t search;
+ std::shared_ptr<connection_client> client;
+ found_next_line_cb_t found_next_line_cb;
+ std::string::size_type max;
+ std::string data;
+public:
+ connection_line_buffer(std::shared_ptr<connection_client> c, found_next_line_cb_t found_next_line_cb_, std::string::size_type max_line_size, eol_search_t search_lb = default_eol_search);
+ connection_line_buffer(std::shared_ptr<connection_client> c, found_next_line_cb_t found_next_line_cb_, std::string::size_type max_line_size);
+private:
+ void conn_data_in_cb(const std::string& data_in);
+};
+
+}
--
GitLab