Feature/delete peek scripts (#174)

* Delete temp script folder

* Delete folder and refactor code

* Add unit tests

* create folder per workspace

* Refactor and move creation to FileUtils

* Separate multiple assignment

src/Microsoft.SqlTools.ServiceLayer/Utility/FileUtils.cs

@@ -8,6 +8,46 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
 {
     internal static class FileUtils
     {
+        internal static string PeekDefinitionTempFolder = Path.GetTempPath() + "mssql_definition"; 
+        internal static bool PeekDefinitionTempFolderCreated = false;
+
+        internal static string GetPeekDefinitionTempFolder()
+        {
+            string tempPath;
+            if (!PeekDefinitionTempFolderCreated)
+            {               
+                try
+                {
+                    // create new temp folder
+                    string tempFolder = string.Format("{0}_{1}", FileUtils.PeekDefinitionTempFolder, DateTime.Now.ToString("yyyyMMddHHmmssffff"));
+                    DirectoryInfo tempScriptDirectory = Directory.CreateDirectory(tempFolder);
+                    FileUtils.PeekDefinitionTempFolder = tempScriptDirectory.FullName;
+                    tempPath = tempScriptDirectory.FullName;
+                    PeekDefinitionTempFolderCreated = true;
+                }
+                catch (Exception)
+                {
+                    // swallow exception and use temp folder to store scripts
+                    tempPath = Path.GetTempPath();
+                }
+            }
+            else
+            {
+                try
+                {
+                    // use tempDirectory name created previously
+                    DirectoryInfo tempScriptDirectory = Directory.CreateDirectory(FileUtils.PeekDefinitionTempFolder);
+                    tempPath = tempScriptDirectory.FullName;
+                }
+                catch (Exception)
+                {
+                    // swallow exception and use temp folder to store scripts
+                    tempPath = Path.GetTempPath();
+                }
+            }
+            return tempPath;
+        }
+
         /// <summary>
         /// Checks if file exists and swallows exceptions, if any
         /// </summary>
@@ -42,5 +82,40 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
             }
         }
 
+        /// <summary>
+        /// Checks if file exists and swallows exceptions, if any
+        /// </summary>
+        /// <param name="path"> path of the file</param>
+        /// <returns></returns>
+        internal static bool SafeDirectoryExists(string path)
+        {
+            try
+            {
+                return Directory.Exists(path);
+            }
+            catch (Exception)
+            {
+                // Swallow exception
+                return false;
+            }
+        }
+
+
+        /// <summary>
+        /// Deletes a directory and swallows exceptions, if any
+        /// </summary>
+        /// <param name="path"></param>
+        internal static void SafeDirectoryDelete(string path, bool recursive)
+        {
+            try
+            {
+                Directory.Delete(path, recursive);
+            }
+            catch (Exception)
+            {
+                // Swallow exception, do nothing
+            }
+        }
+
     }
 }

src/Microsoft.SqlTools.ServiceLayer/Utility/TextUtilities.cs

@@ -6,7 +6,7 @@
 namespace Microsoft.SqlTools.ServiceLayer.Utility
 {
     public static class TextUtilities
-    {       
+    {   
         /// <summary>
         /// Find the position of the cursor in the SQL script content buffer and return previous new line position
         /// </summary>