From 28dbc5c7fa0dd27f8527971f717f7263458bfc62 Mon Sep 17 00:00:00 2001
From: Torben Nehmer <torben.nehmer@terrabit.de>
Date: Tue, 22 Nov 2016 21:50:01 +0100
Subject: [PATCH] Implemented helper methods, equality, comparison and similar
 tools to make handling of NavObjects easier. Reject objects with a Company
 Name set, which we don't support at this point (not sure if this would
 acutally make sense). Adapted test code.

---
 NAV Source Control Test Host/Program.cs  |   2 +-
 NAVSCM Library/NavInterface/NavObject.cs | 137 ++++++++++++++++++++++-
 2 files changed, 136 insertions(+), 3 deletions(-)

diff --git a/NAV Source Control Test Host/Program.cs b/NAV Source Control Test Host/Program.cs
index d89e7c6..5a895db 100644
--- a/NAV Source Control Test Host/Program.cs	
+++ b/NAV Source Control Test Host/Program.cs	
@@ -44,7 +44,7 @@ namespace NavScm.TestHost
                 log.DebugFormat("Row {6}/{7}: Type {0}, ID {1}, Name {2}, Modified {3} {4}, Version {5}",
                     o.Type, o.ID, o.Name, o.Date.ToShortDateString(), o.Time.ToShortTimeString(), o.Version_List, i++, count);
 
-                foundObjects.Add(String.Format("{0}.{1}", o.Type, o.ID), o);
+                foundObjects.Add(o.CacheKey, o);
             }
 
             log.InfoFormat("Collection has {0} entries, writing to cache.xml", foundObjects.Count);
diff --git a/NAVSCM Library/NavInterface/NavObject.cs b/NAVSCM Library/NavInterface/NavObject.cs
index 2e04e4a..f2a0493 100644
--- a/NAVSCM Library/NavInterface/NavObject.cs	
+++ b/NAVSCM Library/NavInterface/NavObject.cs	
@@ -7,8 +7,141 @@ using System.Threading.Tasks;
 
 namespace NavScm.NavInterface
 {
-    partial class NavObject 
+    /// <summary>
+    /// Adds a mapping between the NAV SQL Type field an enum to make its handling easier.
+    /// </summary>
+    public enum NavObjectType
     {
-        
+        TableData = 0,
+        Table = 1,
+        Report = 3,
+        Codeunit = 5,
+        XmlPort = 6,
+        MenuSuite = 7,
+        Page = 8,
+        Query = 9
+    }
+
+    /// <summary>
+    /// <para>
+    /// This class wraps the actual NAV Object table data retrieved from the target database.
+    /// It adds additional helper functions to manage the cache accociated with it.
+    /// </para>
+    /// <para>
+    /// Note, that equality is defined by the DB primary key, which in turn includes
+    /// Type and ID. See <see cref="P:NavScm.NavInterface.NavObject.CacheKey">CacheKey</see>
+    /// for details. This sequence is also used for ordering of the object in case of
+    /// a sorted output.
+    /// </para>
+    /// <para>
+    /// Note, that object entries with a Company Name set are rejected at this point. They
+    /// result (probably) from a multi-tenancy/extension setup, which we do not support at
+    /// this time. As well, objects with unknown object types are rejected.
+    /// </para>
+    /// </summary>
+    /// <seealso cref="NavSQLDataContext"/>
+    /// <seealso cref="NavObjectType"/>
+    partial class NavObject : IEquatable<NavObject>, IComparable, IComparable<NavObject>
+    {
+        /// <summary>
+        /// Validate restrictions on supported objects as outlined in the class description.
+        /// </summary>
+        partial void OnLoaded()
+        {
+            if (Company_Name.Length > 0)
+                throw new InvalidOperationException($"The object {CacheKey} holds a variant with the company name {Company_Name}, which is unsupported");
+            if (Type < 0 || Type == 2 || Type == 4 || Type > 9)
+                throw new InvalidOperationException($"The object type of {CacheKey} is unsupported");
+        }
+
+        /// <summary>
+        /// Casts the SQL type to the corresponding Enum.
+        /// </summary>
+        public NavObjectType NavType
+        {
+            get { return (NavObjectType)Type; }
+        }
+
+        /// <summary>
+        /// <para>
+        /// Constructs an object cache key to uniquely identify the object out of its type and ID.
+        /// Uses the string representation to make debugging easier. The equality operator maps to 
+        /// this key as well.
+        /// </para>
+        /// <para>
+        /// Note, that the company Name is ignored here, as we do not support this scenario at this
+        /// time and throw an error just in case.
+        /// </para>
+        /// </summary>
+        public string CacheKey
+        {
+            get {
+                return $"{Type}.{ID}";
+            }   
+        }
+
+        /// <summary>
+        /// Converts the Date and Time fields to a combined Date/Time value.
+        /// </summary>
+        public DateTime Modified
+        {
+            get
+            {
+                return Date.Add(Time.TimeOfDay);
+            }
+        }
+
+        /// <summary>
+        /// Constructs a hash key based on Type and ID.
+        /// </summary>
+        /// <returns>Take 4 Bits of object Type and 28 bits of the actual object ID and shuffle them around
+        /// to create the hash key.</returns>
+        public override int GetHashCode()
+        {
+            return
+                // lower 8 bits of ID first
+                  (ID << 24)
+                // second byte of ID goes next
+                & ((ID << 8) ^ 0x00ff0000)
+                // third byte of ID goes next
+                & ((ID >> 8) ^ 0x0000ff00)
+                // lower 4 bits of fourth ID byte go next
+                & ((ID >> 20) ^ 0x000000f0)
+                // finally add the first four bits of the Type
+                & (Type ^ 0x0000000f)               
+            ;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (!(obj is NavObject)) return false;
+            return Equals((NavObject) obj);
+        }
+
+        public bool Equals(NavObject other)
+        {
+            return Type == other.Type
+                && ID == other.ID;
+        }
+
+        public int CompareTo(NavObject other)
+        {
+            if (Type < other.Type)
+                return -1;
+            if (Type > other.Type)
+                return +1;
+            if (ID < other.ID)
+                return -1;
+            if (ID > other.ID)
+                return +1;
+            return 0;
+        }
+
+        public int CompareTo(object obj)
+        {
+            if (!(obj is NavObject))
+                throw new InvalidOperationException("obj is not an NavObject");
+            return this.CompareTo((NavObject)obj);
+        }
     }
 }