From 451bedd4e0f040a2676831463ed0bba6f32eaea1 Mon Sep 17 00:00:00 2001
From: Menno van Lavieren <menno.van.lavieren@uname-it.nl>
Date: Fri, 23 Jun 2017 18:07:53 +0200
Subject: [PATCH] Build a connectionstring parser, needs integration and
 testing

---
 Tapeti/Helpers/ConnectionstringParser.cs | 125 +++++++++++++++++++++++
 Tapeti/Tapeti.csproj                     |   1 +
 2 files changed, 126 insertions(+)
 create mode 100644 Tapeti/Helpers/ConnectionstringParser.cs

diff --git a/Tapeti/Helpers/ConnectionstringParser.cs b/Tapeti/Helpers/ConnectionstringParser.cs
new file mode 100644
index 0000000..f2ed10e
--- /dev/null
+++ b/Tapeti/Helpers/ConnectionstringParser.cs
@@ -0,0 +1,125 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tapeti.Helpers
+{
+    public class ConnectionstringParser
+    {
+        readonly TapetiConnectionParams result = new TapetiConnectionParams();
+
+        readonly string connectionstring;
+        int pos = -1;
+        char current = '\0';
+
+        public static TapetiConnectionParams Parse(string connectionstring)
+        {
+            return new ConnectionstringParser(connectionstring).result;
+        }
+
+        private ConnectionstringParser(string connectionstring)
+        {
+            this.connectionstring = connectionstring;
+
+            while (MoveNext())
+            {
+                ParseKV();
+            }
+        }
+
+        private void ParseKV()
+        {
+            var key = ParseKey();
+
+            if (current == '=')
+            {
+                MoveNext();
+                var value = ParseValue();
+                SetValue(key, value);
+            }
+            else
+            {
+                EnableKey(key);
+            }
+        }
+
+        private string ParseKey()
+        {
+            var keyBuilder = new StringBuilder();
+            do
+            {
+                switch (current)
+                {
+                    case '=':
+                    case ';':
+                        return keyBuilder.ToString();
+                    case '"':
+                        break;
+                    default:
+                        keyBuilder.Append(current);
+                        break;
+                }
+            }
+            while (MoveNext());
+
+            return keyBuilder.ToString();
+        }
+
+        private string ParseValue()
+        {
+            var valueBuilder = new StringBuilder();
+            if (current == '"')
+            {
+                while (current == '"') // support two double quotes to be an escaped quote
+                {
+                    while (MoveNext() && current != '"')
+                    {
+                        valueBuilder.Append(current);
+                    }
+                    MoveNext(); // consume the trailing double quote
+                }
+            }
+            else
+            {
+                while (current != ';')
+                    valueBuilder.Append(current);
+            }
+
+            // Always leave the ';' to be consumed by the caller
+            return valueBuilder.ToString();
+        }
+
+        private bool MoveNext()
+        {
+            var n = pos + 1;
+            if (n < connectionstring.Length)
+            {
+                pos = n;
+                current = connectionstring[pos];
+                return true;
+            }
+            pos = connectionstring.Length;
+            current = '\0';
+            return false;
+        }
+
+        private void EnableKey(string key)
+        {
+
+        }
+
+        private void SetValue(string key, string value)
+        {
+            switch (key.ToLowerInvariant()) {
+                case "HostName": result.HostName = value; break;
+                case "Port": result.Port = int.Parse(value); break;
+                case "VirtualHost": result.VirtualHost = value; break;
+                case "Username": result.Username = value; break;
+                case "Password": result.Password = value; break;
+                case "PrefetchCount": result.PrefetchCount = ushort.Parse(value); break;
+            }
+        }
+    }
+}
diff --git a/Tapeti/Tapeti.csproj b/Tapeti/Tapeti.csproj
index 12ef812..fb2fd52 100644
--- a/Tapeti/Tapeti.csproj
+++ b/Tapeti/Tapeti.csproj
@@ -68,6 +68,7 @@
     <Compile Include="Default\NamespaceMatchExchangeStrategy.cs" />
     <Compile Include="Default\RequeueExceptionStrategy.cs" />
     <Compile Include="Default\TypeNameRoutingKeyStrategy.cs" />
+    <Compile Include="Helpers\ConnectionstringParser.cs" />
     <Compile Include="Helpers\ConsoleHelper.cs" />
     <Compile Include="Helpers\MiddlewareHelper.cs" />
     <Compile Include="Helpers\TaskTypeHelper.cs" />