From 861474e0cee5e90265e8b7ff81f232ad2b366ce1 Mon Sep 17 00:00:00 2001
From: Charles Kerr <charles@charleskerr.com>
Date: Sat, 13 Nov 2021 23:23:19 -0600
Subject: [PATCH] refactor: tr session.tos (#2149)

* refactor: make tr_session.tos string_view-friendly
---
 libtransmission/session.cc          | 51 +++++++++++------------------
 libtransmission/utils.h             | 10 ++++++
 tests/libtransmission/utils-test.cc | 11 +++++++
 3 files changed, 40 insertions(+), 32 deletions(-)

diff --git a/libtransmission/session.cc b/libtransmission/session.cc
index bcb7f2908..0aab5d809 100644
--- a/libtransmission/session.cc
+++ b/libtransmission/session.cc
@@ -256,58 +256,40 @@ tr_address const* tr_sessionGetPublicAddress(tr_session const* session, int tr_a
 ****
 ***/
 
-#ifdef TR_LIGHTWEIGHT
-#define TR_DEFAULT_ENCRYPTION TR_CLEAR_PREFERRED
-#else
-#define TR_DEFAULT_ENCRYPTION TR_ENCRYPTION_PREFERRED
-#endif
-
-static int parse_tos(char const* tos)
+static int parse_tos(std::string_view tos_in)
 {
-    if (evutil_ascii_strcasecmp(tos, "") == 0)
+    auto tos = tr_strlower(tr_strvStrip(tos_in));
+
+    if (tos == ""sv || tos == "default"sv)
     {
         return 0;
     }
 
-    if (evutil_ascii_strcasecmp(tos, "default") == 0)
-    {
-        return 0;
-    }
-
-    if (evutil_ascii_strcasecmp(tos, "lowcost") == 0)
+    if (tos == "lowcost"sv || tos == "mincost"sv)
     {
         return TR_IPTOS_LOWCOST;
     }
 
-    if (evutil_ascii_strcasecmp(tos, "mincost") == 0)
-    {
-        return TR_IPTOS_LOWCOST;
-    }
-
-    if (evutil_ascii_strcasecmp(tos, "throughput") == 0)
+    if (tos == "throughput"sv)
     {
         return TR_IPTOS_THRUPUT;
     }
 
-    if (evutil_ascii_strcasecmp(tos, "reliability") == 0)
+    if (tos == "reliability"sv)
     {
         return TR_IPTOS_RELIABLE;
     }
 
-    if (evutil_ascii_strcasecmp(tos, "lowdelay") == 0)
+    if (tos == "lowdelay"sv)
     {
         return TR_IPTOS_LOWDELAY;
     }
 
-    char* p = nullptr;
-    int const value = strtol(tos, &p, 0);
-    return p == nullptr || p == tos ? 0 : value;
+    return std::stoi(tos);
 }
 
-static char const* format_tos(int value)
+static std::string format_tos(int value)
 {
-    static char buf[8];
-
     switch (value)
     {
     case 0:
@@ -326,11 +308,16 @@ static char const* format_tos(int value)
         return "lowdelay";
 
     default:
-        tr_snprintf(buf, 8, "%d", value);
-        return buf;
+        return std::to_string(value);
     }
 }
 
+#ifdef TR_LIGHTWEIGHT
+#define TR_DEFAULT_ENCRYPTION TR_CLEAR_PREFERRED
+#else
+#define TR_DEFAULT_ENCRYPTION TR_ENCRYPTION_PREFERRED
+#endif
+
 void tr_sessionGetDefaultSettings(tr_variant* d)
 {
     TR_ASSERT(tr_variantIsDict(d));
@@ -851,9 +838,9 @@ static void sessionSetImpl(void* vdata)
         tr_sessionSetEncryption(session, tr_encryption_mode(i));
     }
 
-    if (tr_variantDictFindStr(settings, TR_KEY_peer_socket_tos, &strVal, nullptr))
+    if (tr_variantDictFindStrView(settings, TR_KEY_peer_socket_tos, &sv))
     {
-        session->peerSocketTOS = parse_tos(strVal);
+        session->peerSocketTOS = parse_tos(sv);
     }
 
     if (tr_variantDictFindStr(settings, TR_KEY_peer_congestion_algorithm, &strVal, nullptr))
diff --git a/libtransmission/utils.h b/libtransmission/utils.h
index 1b77cfbd5..765e57adf 100644
--- a/libtransmission/utils.h
+++ b/libtransmission/utils.h
@@ -8,6 +8,8 @@
 
 #pragma once
 
+#include <algorithm>
+#include <cctype>
 #include <cinttypes>
 #include <cstdarg>
 #include <cstddef>
@@ -251,6 +253,14 @@ char const* tr_memmem(char const* haystack, size_t haystack_len, char const* nee
 /** @brief Portability wrapper for strcasestr() that uses the system implementation if available */
 char const* tr_strcasestr(char const* haystack, char const* needle);
 
+template<typename T>
+std::string tr_strlower(T in)
+{
+    auto out = std::string{ in };
+    std::for_each(std::begin(out), std::end(out), [](char& ch) { ch = std::tolower(ch); });
+    return out;
+}
+
 /***
 ****  std::string_view utils
 ***/
diff --git a/tests/libtransmission/utils-test.cc b/tests/libtransmission/utils-test.cc
index 7b09d8849..f593c8e1a 100644
--- a/tests/libtransmission/utils-test.cc
+++ b/tests/libtransmission/utils-test.cc
@@ -301,6 +301,17 @@ TEST_F(UtilsTest, lowerbound)
     }
 }
 
+TEST_F(UtilsTest, trStrlower)
+{
+    EXPECT_EQ(""sv, tr_strlower(""sv));
+    EXPECT_EQ("apple"sv, tr_strlower("APPLE"sv));
+    EXPECT_EQ("apple"sv, tr_strlower("Apple"sv));
+    EXPECT_EQ("apple"sv, tr_strlower("aPPLe"sv));
+    EXPECT_EQ("apple"sv, tr_strlower("applE"sv));
+    EXPECT_EQ("hello"sv, tr_strlower("HELLO"sv));
+    EXPECT_EQ("hello"sv, tr_strlower("hello"sv));
+}
+
 TEST_F(UtilsTest, trMemmem)
 {
     auto const haystack = std::string{ "abcabcabcabc" };