Change SourceChanged event on ImageSource to weak event to allow Images (#268)

referencing application-wide StaticResource ImageSources to be GCed

4 files changed, 180 insertions, 0 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069.cs
new file mode 100644
index 00000000..7abfa5d3
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069.cs
@@ -0,0 +1,74 @@
+using System;
+using Xamarin.Forms.Controls.Issues;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+namespace Xamarin.Forms.Controls
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 42069, "Garbage Collector can not collect pages that use ImageSource as a StaticResource",
+		PlatformAffected.All)]
+	public class Bugzilla42069 : TestNavigationPage
+	{
+		protected override void Init()
+		{
+			if (Application.Current.Resources == null)
+			{
+				Application.Current.Resources = new ResourceDictionary();
+			}
+
+			if (!Application.Current.Resources.ContainsKey("SomeSmallImage"))
+			{
+				var smallImage = new OnPlatform<ImageSource> {
+					Android = ImageSource.FromFile("coffee.png"),
+					WinPhone = ImageSource.FromFile("bank.png"),
+					iOS = ImageSource.FromFile("coffee.png")
+				};
+
+				Application.Current.Resources.Add("SomeSmallImage", smallImage);
+			}
+
+			const string instructions1 = @"Tap the Start button and follow the instructions on the next page.";
+			string instructions2 =
+				$"When you return to this page, tap the Collect button. The message \n'{Bugzilla42069_Page.DestructorMessage}'\n should appear at least once in the debug output.";
+
+			var label1 = new Label { Text = instructions1 };
+			var label2 = new Label { Text = instructions2, HorizontalTextAlignment = TextAlignment.Center };
+
+			var startButton = new Button { Text = "Start" };
+			startButton.Clicked += (sender, args) =>
+			{
+				// We have to do the push-pop-push dance because NavigationPage
+				// holds a reference to its last page for unrelated reasons; our concern 
+				// here is that the first Bugzilla42069_Page that we pushed gets collected
+				PushAsync(new Bugzilla42069_Page(), false);
+				PopAsync(false);
+				PushAsync(new Bugzilla42069_Page(), false);
+			};
+
+			var collectButton = new Button { Text = "Collect" };
+			collectButton.Clicked += (sender, args) =>
+			{
+				GC.Collect();
+				GC.Collect();
+				GC.Collect();
+			};
+
+			var startPage = new ContentPage
+			{
+				Content = new StackLayout
+				{
+					Children =
+					{
+						label1,
+						startButton,
+						label2,
+						collectButton
+					}
+				}
+			};
+
+			PushAsync(startPage);
+		}
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069_Page.xaml b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069_Page.xaml
new file mode 100644
index 00000000..5f98e198
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069_Page.xaml
@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Xamarin.Forms.Controls.Issues.Bugzilla42069_Page">
+	<StackLayout>
+		<Image x:Name="ChangingImage" />
+		<Button x:Name="Button2" Text="Change Image"></Button>
+		<Label Text="Tap the 'Change Image' button; the image at the top should toggle between two images. If the image doesn't toggle, the test has failed." ></Label>
+		<Label Text="There should be several instances of the same image below." ></Label>
+		<Button x:Name="Button" Text="Back"></Button>
+		<Label Text="Tap the 'Back' button." ></Label>
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage} "/>
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+		<Image Source="{StaticResource SomeSmallImage}" />
+	</StackLayout>
+</ContentPage>
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069_Page.xaml.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069_Page.xaml.cs
new file mode 100644
index 00000000..2031e56c
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla42069_Page.xaml.cs
@@ -0,0 +1,36 @@
+using System;
+using System.Diagnostics;
+using System.Threading;
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	public partial class Bugzilla42069_Page : ContentPage
+	{
+		public const string DestructorMessage = ">>>>>>>>>> Bugzilla42069_Page destructor <<<<<<<<<<";
+
+		public Bugzilla42069_Page()
+		{
+			InitializeComponent();
+
+			ImageWhichChanges = ImageSource.FromFile("oasissmall.jpg") as FileImageSource;
+
+			ChangingImage.SetBinding(Image.SourceProperty, nameof(ImageWhichChanges));
+
+			Button.Clicked += (sender, args) => Navigation.PopAsync(false);
+
+			Button2.Clicked += (sender, args) =>
+			{
+				ImageWhichChanges.File = ImageWhichChanges.File == "bank.png" ? "oasissmall.jpg" : "bank.png";
+			};
+
+			BindingContext = this;
+		}
+
+		~Bugzilla42069_Page()
+		{
+			Debug.WriteLine(DestructorMessage);
+		}
+
+		public FileImageSource ImageWhichChanges { get; set; }
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index 6531b47d..a98b97dc 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -110,6 +110,11 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40998.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41205.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41424.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42069.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42069_Page.xaml.cs">
+      <DependentUpon>Bugzilla42069_Page.xaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42074.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42075.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)CarouselAsync.cs" />
@@ -544,4 +549,10 @@
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
   </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Bugzilla42069_Page.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+  </ItemGroup>
 </Project>
\ No newline at end of file