refactor: add util tr_strvstrip() to strip string_views (#2077)

libtransmission/utils.cc

@@ -591,6 +591,22 @@ char* tr_strsep(char** str, char const* delims)
 #endif
 }
 
+std::string_view tr_strvstrip(std::string_view str)
+{
+    auto constexpr test = [](auto ch)
+    {
+        return isspace(ch);
+    };
+
+    auto const it = std::find_if_not(std::begin(str), std::end(str), test);
+    str.remove_prefix(std::distance(std::begin(str), it));
+
+    auto const rit = std::find_if_not(std::rbegin(str), std::rend(str), test);
+    str.remove_suffix(std::distance(std::rbegin(str), rit));
+
+    return str;
+}
+
 char* tr_strstrip(char* str)
 {
     if (str != nullptr)

libtransmission/utils.h

@@ -256,6 +256,8 @@ char const* tr_strerror(int errnum);
     @return the stripped string */
 char* tr_strstrip(char* str);
 
+std::string_view tr_strvstrip(std::string_view str);
+
 /** @brief Returns true if the string ends with the specified case-insensitive suffix */
 bool tr_str_has_suffix(char const* str, char const* suffix);
 

tests/libtransmission/utils-test.cc

@@ -68,6 +68,14 @@ TEST_F(UtilsTest, trStrstrip)
     EXPECT_EQ(in, out);
     EXPECT_STREQ("test", out);
     tr_free(in);
+
+    EXPECT_EQ(""sv, tr_strvstrip("              "sv));
+    EXPECT_EQ("test test"sv, tr_strvstrip("    test test     "sv));
+    EXPECT_EQ("test"sv, tr_strvstrip("   test     "sv));
+    EXPECT_EQ("test"sv, tr_strvstrip("   test "sv));
+    EXPECT_EQ("test"sv, tr_strvstrip(" test       "sv));
+    EXPECT_EQ("test"sv, tr_strvstrip(" test "sv));
+    EXPECT_EQ("test"sv, tr_strvstrip("test"sv));
 }
 
 TEST_F(UtilsTest, trBuildpath)