From eb3466a86bf085883e6ccf637698dd196cd78b9e Mon Sep 17 00:00:00 2001
From: RitchieF <ritchie.p.flick@gmail.com>
Date: Sun, 2 Apr 2017 20:46:37 +0200
Subject: [PATCH 1/2] Bugfix: Crash while saving when hosts was disabled and
 enabled together

When the HostsFile was disabled (hosts.disabled file exists and no hosts file), saving would lead the program to create a new hosts file. If the user wanted to disable the HostsFile the again, the program would crash.

Now before saving the program checks if there exists a hosts.disabled file and if yes, tells the user that he/she needs to enable the HostsFile before editing entries.
---
 src/HostsFile.cs | 5 +++++
 src/MainForm.cs  | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/src/HostsFile.cs b/src/HostsFile.cs
index ea1b131..bc963ba 100644
--- a/src/HostsFile.cs
+++ b/src/HostsFile.cs
@@ -182,6 +182,11 @@ public int LineCount
             }
         }
 
+        /// <summary>
+        /// Gets value indicating if the HostsFile is currently disabled.
+        /// </summary>
+        public static bool IsDisabled => File.Exists(DefaultDisabledHostFilePath);
+
         #endregion
 
         #region Public Methods
diff --git a/src/MainForm.cs b/src/MainForm.cs
index 94177d7..9169000 100644
--- a/src/MainForm.cs
+++ b/src/MainForm.cs
@@ -614,6 +614,12 @@ private void OnSaveClick(object sender, EventArgs e)
             this.dataGridViewHostsEntries.CommitEdit(
                 DataGridViewDataErrorContexts.Commit);
 
+            if (HostsFile.IsDisabled)
+            {
+                MessageBox.Show("The HostsFile is currently disabled. Enable the HostsFile before editing entries.");
+                return;
+            }
+
             HostsFile.Instance.Save();
         }
 

From 07fcffff548fecccc76442ed7e0d2f3bc871fe3d Mon Sep 17 00:00:00 2001
From: RitchieF <ritchie.p.flick@gmail.com>
Date: Sun, 2 Apr 2017 21:01:50 +0200
Subject: [PATCH 2/2] Check for Enabled and Disabled HostsFile

Added an additional check to make sure that the program doesn't crash when both enabled and disabled HostsFile exist at the same time.
---
 src/HostsFile.cs | 10 ++++++++++
 src/MainForm.cs  | 24 ++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/HostsFile.cs b/src/HostsFile.cs
index bc963ba..2d5c1af 100644
--- a/src/HostsFile.cs
+++ b/src/HostsFile.cs
@@ -196,6 +196,11 @@ public int LineCount
         /// </summary>
         public static void DisableHostsFile()
         {
+            if (IsEnabled && IsDisabled)
+            {
+                throw new InvalidOperationException("The HostsFile is enabled and disabled at the same time.");
+            }
+
             using (FileEx.DisableAttributes(DefaultHostFilePath, FileAttributes.ReadOnly))
             {
                 File.Move(DefaultHostFilePath, DefaultDisabledHostFilePath);
@@ -208,6 +213,11 @@ public static void DisableHostsFile()
         /// </summary>
         public static void EnableHostsFile()
         {
+            if (IsEnabled && IsDisabled)
+            {
+                throw new InvalidOperationException("The HostsFile is enabled and disabled at the same time.");
+            }
+
             using (FileEx.DisableAttributes(DefaultDisabledHostFilePath, FileAttributes.ReadOnly))
             {
                 File.Move(DefaultDisabledHostFilePath, DefaultHostFilePath);
diff --git a/src/MainForm.cs b/src/MainForm.cs
index 9169000..af66bbd 100644
--- a/src/MainForm.cs
+++ b/src/MainForm.cs
@@ -312,11 +312,31 @@ private void OnDisableHostsClick(object sender, EventArgs e)
 
             if (checkState)
             {
-                HostsFile.EnableHostsFile();
+                try
+                {
+                    HostsFile.EnableHostsFile();
+                }
+                catch (InvalidOperationException invalidOperationException)
+                {
+                    Console.WriteLine(invalidOperationException);
+                    MessageBox.Show(invalidOperationException.Message, "Error during operation!", MessageBoxButtons.OK,
+                        MessageBoxIcon.Error);
+                    return;
+                }
             }
             else
             {
-                HostsFile.DisableHostsFile();
+                try
+                {
+                    HostsFile.DisableHostsFile();
+                }
+                catch (InvalidOperationException invalidOperationException)
+                {
+                    Console.WriteLine(invalidOperationException);
+                    MessageBox.Show(invalidOperationException.Message, "Error during operation!", MessageBoxButtons.OK,
+                        MessageBoxIcon.Error);
+                    return;
+                }
             }
 
             this.UpdateNotifyIcon();