Add Agent Job and Job Step request handlers (#635)

* Stage changes

* Fix update job request handler

* WIP

* Additional agent handler updates

* Setup agent job step create test

* Fix Step update handler

src/Microsoft.SqlTools.ServiceLayer/Management/Common/DbSize.cs

@@ -0,0 +1,173 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Microsoft.SqlServer.Management.Common;
+
+namespace Microsoft.SqlTools.ServiceLayer.Management
+{
+    /// <summary>
+    /// Helper class to describe the size of an Azure database
+    /// </summary>
+    public class DbSize
+    {
+        public enum SizeUnits
+        {
+            MB,
+            GB,
+            TB
+        }
+
+        #region Member Vars
+
+        private readonly int size;
+        private readonly SizeUnits sizeUnit;
+
+        #endregion 
+
+
+        public DbSize(int size, SizeUnits sizeUnit)
+        {
+            this.size = size;
+            this.sizeUnit = sizeUnit;
+        }
+
+        /// <summary>
+        /// Copy constructor
+        /// </summary> 
+        public DbSize(DbSize copy)
+        {
+            this.size = copy.Size;
+            this.sizeUnit = copy.SizeUnit;
+        }
+        
+        /// <summary>
+        /// Size of the DB
+        /// </summary>
+        public int Size
+        {
+            get
+            {
+                return size;
+            }
+        }
+
+        /// <summary>
+        /// Units that the size is measured in 
+        /// </summary>
+        public SizeUnits SizeUnit
+        {
+            get
+            {
+                return sizeUnit;
+            }
+        }
+
+        /// <summary>
+        /// Returns the number of bytes represented by the DbSize
+        /// </summary>
+        public double SizeInBytes
+        {
+            get
+            {
+                var sizeBase = Convert.ToDouble(this.size);
+                switch (SizeUnit)
+                {
+                    case SizeUnits.MB:
+                        return sizeBase*1024.0*1024.0;
+                    case SizeUnits.GB:
+                        return sizeBase*1024.0*1024.0*1024.0;
+                    case SizeUnits.TB:
+                        return sizeBase*1024.0*1024.0*1024.0*1024.0;
+                }
+                throw new InvalidOperationException("SR.UnknownSizeUnit(SizeUnit.ToString())");
+            }
+        }
+        #region Object Overrides 
+        /// <summary>
+        /// Displays the size in the format ####UU (e.g. 100GB)
+        /// </summary>
+        /// <returns></returns>
+        public override string ToString()
+        {
+            return size + sizeUnit.ToString();
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (obj == null || GetType() != obj.GetType())
+            {
+                return false;
+            }
+
+            return this == (DbSize)obj;
+        }
+
+        public override int GetHashCode()
+        {
+            return this.size.GetHashCode() ^ this.sizeUnit.GetHashCode();
+        }
+
+        #endregion Object Overrides
+
+        /// <summary>
+        /// Parses a string in the format ####UU into a DbSize object. The number of
+        /// numeric characters must be parseable into an int and the last two characters
+        /// mapped to one of the SizeUnits enum values. 
+        /// </summary>
+        /// <param name="dbSizeString"></param>
+        /// <returns></returns>
+        public static DbSize ParseDbSize(string dbSizeString)
+        {
+            if (dbSizeString == null || dbSizeString.Length < 3)
+            { //Sanity check
+                throw new ArgumentException("DbSize string must be at least 3 characters (#UU)");
+            }
+            int size;
+            //Try and parse all but the last two characters into the size
+            if (int.TryParse(dbSizeString.Substring(0, dbSizeString.Length - 2), out size))
+            {
+                //Get the unit portion (last two characters)
+                string unitPortion = dbSizeString.Substring(dbSizeString.Length - 2 );
+                SizeUnits unit;
+                if (Enum.TryParse(unitPortion, true, out unit))
+                {
+                    return new DbSize(size, unit);
+                }
+                else
+                {
+                    throw new ArgumentException("DbSize string does not contain a valid unit portion");
+                }
+            }
+            else
+            {
+                throw new ArgumentException("DbSize string does not contain a valid numeric portion");
+            }
+        }
+
+        public static bool operator ==(DbSize x, DbSize y)
+        {
+            if(ReferenceEquals(x, y))
+            { //Both null or both same instance, are equal
+                return true;
+            }
+
+            if((object)x == null || (object)y == null)
+            { //Only one null, never equal (cast to object to avoid infinite loop of ==)
+                return false;
+            }
+
+            return x.size == y.size && x.sizeUnit == y.sizeUnit;
+        }
+
+        public static bool operator !=(DbSize x, DbSize y)
+        {
+            return !(x == y);
+        }
+    }
+}