Introduce Strings::Joiner

2 files changed, 29 insertions, 16 deletions

diff --git a/toolsrc/src/SourceParagraph.cpp b/toolsrc/src/SourceParagraph.cpp
index eef4a4734..8bfe8e84d 100644
--- a/toolsrc/src/SourceParagraph.cpp
+++ b/toolsrc/src/SourceParagraph.cpp
@@ -53,8 +53,8 @@ namespace vcpkg
             const std::vector<std::string> remaining_fields = Maps::extract_keys(fields);
             const std::vector<std::string>& valid_fields = get_list_of_valid_fields();
 
-            const std::string remaining_fields_as_string = Strings::join(remaining_fields, "\n    ");
-            const std::string valid_fields_as_string = Strings::join(valid_fields, "\n    ");
+            const std::string remaining_fields_as_string = Strings::Joiner::on("\n    ").join(remaining_fields);
+            const std::string valid_fields_as_string = Strings::Joiner::on("\n    ").join(valid_fields);
 
             System::println(System::color::error, "Error: There are invalid fields in the Source Paragraph of %s", this->name);
             System::println("The following fields were not expected:\n\n    %s\n\n", remaining_fields_as_string);
diff --git a/toolsrc/src/vcpkg_Strings.cpp b/toolsrc/src/vcpkg_Strings.cpp
index 5b6d9967c..3b9d6a859 100644
--- a/toolsrc/src/vcpkg_Strings.cpp
+++ b/toolsrc/src/vcpkg_Strings.cpp
@@ -67,25 +67,38 @@ namespace vcpkg::Strings
         return output;
     }
 
-    std::string join(const std::vector<std::string>& v, const std::string& delimiter)
+    std::string join(const std::vector<std::string>& v, const std::string& prefix, const std::string& delimiter, const std::string& suffix)
     {
-        if (v.empty())
+        return join(v, prefix, delimiter, suffix, [](const std::string& i) -> std::string
         {
-            return std::string();
-        }
+            return i;
+        });
+    }
 
-        std::string output;
-        size_t size = v.size();
+    Joiner Joiner::on(const std::string& delimiter)
+    {
+        return Joiner(delimiter);
+    }
 
-        output.append(v.at(0));
+    Joiner& Joiner::prefix(const std::string& prefix)
+    {
+        this->m_prefix = prefix;
+        return *this;
+    }
 
-        for (size_t i = 1; i < size; ++i)
-        {
-            output.append(delimiter);
-            output.append(v.at(i));
-        }
+    Joiner& Joiner::suffix(const std::string& suffix)
+    {
+        this->m_suffix = suffix;
+        return *this;
+    }
 
-        return output;
+    std::string Joiner::join(const std::vector<std::string>& v) const
+    {
+        return Strings::join(v, this->m_prefix, this->m_delimiter, this->m_suffix);
+    }
+
+    Joiner::Joiner(const std::string& delimiter) : m_prefix(""), m_delimiter(delimiter), m_suffix("")
+    {
     }
 
     void trim(std::string* s)
@@ -119,7 +132,7 @@ namespace vcpkg::Strings
         std::vector<std::string> output;
 
         size_t i = 0;
-        for (size_t pos = s.find(delimiter); pos != std::string::npos;  pos = s.find(delimiter, pos))
+        for (size_t pos = s.find(delimiter); pos != std::string::npos; pos = s.find(delimiter, pos))
         {
             output.push_back(s.substr(i, pos - i));
             i = ++pos;