Use a map of promises for loading favicons

This makes it so:

 - We only try to download each icon once
 - Once an icon is loaded, we can return it immediately from the map
 - Favicon loading is fully async
 - Removed ReloadFavicon signal since we currently don't ever reload them

I merged some of the code so we only have getIcon() and downloadFavicon()

9 files changed, 103 insertions, 201 deletions

diff --git a/src/Backend/Backend.vala b/src/Backend/Backend.vala
index ef681a32..3bdbb6bb 100644
--- a/src/Backend/Backend.vala
+++ b/src/Backend/Backend.vala
@@ -34,7 +34,6 @@ namespace FeedReader {
 		public signal void newFeedList();
 		public signal void refreshFeedListCounter();
 		public signal void updateArticleList();
-		public signal void reloadFavIcons();
 		public signal void showArticleListOverlay();
 		public signal void setOffline();
 		public signal void setOnline();
diff --git a/src/FavIconManager.vala b/src/FavIconManager.vala
index 7693b553..0fa4a4dc 100644
--- a/src/FavIconManager.vala
+++ b/src/FavIconManager.vala
@@ -15,11 +15,9 @@
 
 public class FeedReader.FavIconManager : GLib.Object {
 
-	private Gee.HashMap<string, Gdk.Pixbuf> m_map;
+	private Gee.Map<string, Gee.Future<Gdk.Pixbuf?>> m_map = new Gee.HashMap<string, Gee.Future<Gdk.Pixbuf?>>();
 	private static FavIconManager? m_cache = null;
 
-	public signal void ReloadFavIcon(Feed feed);
-
 	public static FavIconManager get_default()
 	{
 		if(m_cache == null)
@@ -30,76 +28,54 @@ public class FeedReader.FavIconManager : GLib.Object {
 
 	private FavIconManager()
 	{
-		m_map = new Gee.HashMap<string, Gdk.Pixbuf>();
 	}
 
-	private async void load(Feed feed, bool firstTry = true)
+	public async Gdk.Pixbuf? getIcon(Feed feed)
 	{
-		var fileName = GLib.Base64.encode(feed.getFeedID().data) + ".ico";
 		try
 		{
-			var file = File.new_for_path(GLib.Environment.get_user_data_dir() + "/feedreader/data/feed_icons/" + fileName);
-			var stream = yield file.read_async();
-			var pixbuf = yield new Gdk.Pixbuf.from_stream_async(stream);
-			stream.close();
-			if(pixbuf.get_height() <= 1 && pixbuf.get_width() <= 1)
+			var feed_id = feed.getFeedID();
+			var future = m_map.get(feed_id);
+			if(future == null)
 			{
-				Logger.warning(@"FavIconManager: $fileName is too small");
-				return;
-			}
-
-			pixbuf = pixbuf.scale_simple(24, 24, Gdk.InterpType.BILINEAR);
-			m_map.set(feed.getFeedID(), pixbuf);
-			ReloadFavIcon(feed);
-		}
-		catch (IOError.NOT_FOUND e)
-		{
-			//Logger.debug(@"FavIconManager: Icon $fileName does not exist");
-
-			if(!firstTry)
-				return;
+				var promise = new Gee.Promise<Gdk.Pixbuf?>();
+				try
+				{
+					future = promise.future;
+					m_map.set(feed_id, future);
 
-			bool success = yield downloadFavIcon(feed);
-			if(success)
-				yield load(feed, false);
-		}
-		catch(Gdk.PixbufError.UNKNOWN_TYPE e)
-		{
-			Logger.warning(@"FavIconManager.load: Icon $fileName is an unknown type");
-		}
-		catch(Error e)
-		{
-			Logger.error(@"FavIconManager.load: $fileName: %s".printf(e.message));
-		}
-	}
+					var stream = yield downloadFavIcon(feed);
+					if(stream == null)
+						return null;
 
-	private bool hasIcon(Feed feed)
-	{
-		if(m_map == null)
-		{
-			m_map = new Gee.HashMap<string, Gdk.Pixbuf>();
-			return false;
-		}
+					var pixbuf = yield new Gdk.Pixbuf.from_stream_async(stream);
+					stream.close();
 
-		return m_map.has_key(feed.getFeedID());
-	}
+					if(pixbuf.get_height() <= 1 && pixbuf.get_width() <= 1)
+					{
+						Logger.warning(@"FavIconManager: Icon for feed %s is too small".printf(feed.getTitle()));
+						return null;
+					}
+					pixbuf = pixbuf.scale_simple(24, 24, Gdk.InterpType.BILINEAR);
 
-	public async Gdk.Pixbuf? getIcon(Feed feed, bool firstTry = true)
-	{
-		if(hasIcon(feed))
-		{
-			return m_map.get(feed.getFeedID()).copy();
+					promise.set_value(pixbuf);
+				}
+				finally
+				{
+					if(!future.ready)
+						promise.set_value(null);
+				}
+			}
+			return yield future.wait_async();
 		}
-		else if(firstTry)
+		catch(Error e)
 		{
-			yield load(feed);
-			return yield getIcon(feed, false);
+			Logger.error("FavIconManager.getIcon: %s".printf(e.message));
+			return null;
 		}
-
-		return null;
 	}
 
-	private async bool downloadFavIcon(Feed feed, string? hint_url = null, GLib.Cancellable? cancellable = null, string icon_path = GLib.Environment.get_user_data_dir() + "/feedreader/data/feed_icons/")
+	private async InputStream? downloadFavIcon(Feed feed, GLib.Cancellable? cancellable = null, string icon_path = GLib.Environment.get_user_data_dir() + "/feedreader/data/feed_icons/") throws GLib.Error
 	{
 		string filename_prefix = icon_path + feed.getFeedFileName();
 		string local_filename = @"$filename_prefix.ico";
@@ -109,7 +85,7 @@ public class FeedReader.FavIconManager : GLib.Object {
 		DateTime? expires = metadata.expires;
 
 		if(cancellable != null && cancellable.is_cancelled())
-			return false;
+			return null;
 
 		var now = new DateTime.now_utc();
 		if(expires != null)
@@ -117,7 +93,15 @@ public class FeedReader.FavIconManager : GLib.Object {
 			if(expires.to_unix() > now.to_unix())
 			{
 				Logger.debug("Favicon for %s is valid until %s, skipping this time".printf(feed.getTitle(), expires.to_string()));
-				return yield Utils.file_exists(local_filename, FileType.REGULAR);
+				var file = File.new_for_path(local_filename);
+				try
+				{
+					return yield file.read_async();
+				}
+				catch(FileError.NOENT e)
+				{
+					return null;
+				}
 			}
 		}
 
@@ -126,9 +110,6 @@ public class FeedReader.FavIconManager : GLib.Object {
 
 		var obvious_icons = new Gee.ArrayList<string>();
 
-		if(hint_url != null)
-			obvious_icons.add(hint_url);
-
 		if(feed.getIconURL() != null)
 			obvious_icons.add(feed.getIconURL());
 
@@ -147,20 +128,20 @@ public class FeedReader.FavIconManager : GLib.Object {
 			obvious_icons.add(icon_url);
 		}
 
-
 		// Try to find one of those icons
 		foreach(var url in obvious_icons)
 		{
-			if(yield downloadIcon(feed, url, cancellable, icon_path))
-				return true;
+			var stream = yield downloadIcon(feed, url, cancellable, icon_path);
+			if(stream != null)
+				return stream;
 
 			if(cancellable != null && cancellable.is_cancelled())
-				return false;
+				return null;
 		}
 
 		// If all else fails, download html and parse to find location of favicon
 		if(siteURL == null)
-			return false;
+			return null;
 
 		var message_html = new Soup.Message("GET", siteURL);
 		if(Settings.tweaks().get_boolean("do-not-track"))
@@ -175,7 +156,7 @@ public class FeedReader.FavIconManager : GLib.Object {
 		catch (Error e)
 		{
 			Logger.warning(@"Request for $siteURL failed: " + e.message);
-			return false;
+			return null;
 		}
 		if(html != null && message_html.status_code == 200)
 		{
@@ -185,43 +166,47 @@ public class FeedReader.FavIconManager : GLib.Object {
 			if(doc == null)
 			{
 				Logger.debug(@"Utils.downloadFavIcon: parsing html on $siteURL failed");
-				return false;
+				return null;
 			}
 
-			// check for <link rel="icon">
-			var xpath = grabberUtils.getURL(doc, "//link[@rel='icon']");
+			try
+			{
+				// check for <link rel="icon">
+				var xpath = grabberUtils.getURL(doc, "//link[@rel='icon']");
 
-			if(xpath == null)
-				// check for <link rel="shortcut icon">
-				xpath = grabberUtils.getURL(doc, "//link[@rel='shortcut icon']");
+				if(xpath == null)
+					// check for <link rel="shortcut icon">
+					xpath = grabberUtils.getURL(doc, "//link[@rel='shortcut icon']");
 
-			if(xpath == null)
-				// check for <link rel="apple-touch-icon">
-				xpath = grabberUtils.getURL(doc, "//link[@rel='apple-touch-icon']");
+				if(xpath == null)
+					// check for <link rel="apple-touch-icon">
+					xpath = grabberUtils.getURL(doc, "//link[@rel='apple-touch-icon']");
 
-			if(xpath != null)
+				if(xpath != null)
+				{
+					xpath = grabberUtils.completeURL(xpath, siteURL);
+					return yield downloadIcon(feed, xpath, cancellable, icon_path);
+				}
+			}
+			finally
 			{
-				xpath = grabberUtils.completeURL(xpath, siteURL);
-				if(yield downloadIcon(feed, xpath, cancellable, icon_path))
-					return true;
+				delete doc;
 			}
-
-			delete doc;
 		}
 
-		return false;
+		return null;
 	}
 
-	private async bool downloadIcon(Feed feed, string? icon_url, Cancellable? cancellable, string icon_path = GLib.Environment.get_user_data_dir() + "/feedreader/data/feed_icons/")
+	private async InputStream? downloadIcon(Feed feed, string? icon_url, Cancellable? cancellable, string icon_path = GLib.Environment.get_user_data_dir() + "/feedreader/data/feed_icons/") throws GLib.Error
 	{
 		if(icon_url == "" || icon_url == null || GLib.Uri.parse_scheme(icon_url) == null)
 		{
 			Logger.warning(@"Utils.downloadIcon: icon_url not valid $icon_url");
-			return false;
+			return null;
 		}
 
 		if(!yield Utils.ensure_path(icon_path))
-			return false;
+			return null;
 
 		string filename_prefix = icon_path + feed.getFeedFileName();
 		string local_filename = @"$filename_prefix.ico";
@@ -250,46 +235,29 @@ public class FeedReader.FavIconManager : GLib.Object {
 		catch (Error e)
 		{
 			Logger.error(@"Request for $icon_url failed: " + e.message);
-			return false;
+			return null;
 		}
 		var status = message.status_code;
 		if(status == 304)
 		{
-			return true;
+			var file = File.new_for_path(local_filename);
+			return yield file.read_async();
 		}
 		else if(status == 404 || data == null)
 		{
-			return false;
+			return null;
 		}
 		else if(status == 200)
 		{
 			var local_file = File.new_for_path(local_filename);
-			uint8[]? local_data = null;
 			try
 			{
-				uint8[] contents;
-				yield local_file.load_contents_async(null, out contents, null);
-				local_data = contents;
+				yield local_file.replace_contents_async(data, null, false, FileCreateFlags.NONE, null, null);
 			}
-			catch(IOError.NOT_FOUND e){}
 			catch(Error e)
 			{
-				Logger.error(@"Error reading icon $local_filename: %s".printf(e.message));
-			}
-
-			if(local_data == null
-			||(local_data != null && data != local_data))
-			{
-				try
-				{
-					yield local_file.replace_contents_async(data, null, false, FileCreateFlags.NONE, null, null);
-					FileUtils.set_data(local_filename, data);
-				}
-				catch(Error e)
-				{
-					Logger.error("Error writing icon: %s".printf(e.message));
-					return false;
-				}
+				Logger.error("Error writing icon: %s".printf(e.message));
+				return null;
 			}
 
 			metadata.etag = message.response_headers.get_one("ETag");
@@ -303,7 +271,6 @@ public class FeedReader.FavIconManager : GLib.Object {
 					var parts = header.split("=");
 					if(parts.length < 2 || parts[0] != "max-age")
 						continue;
-					Logger.debug(parts[1]);
 					var seconds = int64.parse(parts[1]);
 					var expires = new DateTime.now_utc();
 					expires.add_seconds(seconds);
@@ -313,9 +280,10 @@ public class FeedReader.FavIconManager : GLib.Object {
 			}
 			metadata.last_modified = message.response_headers.get_one("Last-Modified");
 			yield metadata.save_to_file_async(metadata_filename);
-			return true;
+			return new MemoryInputStream.from_data(data);
 		}
+
 		Logger.warning(@"Could not download icon for feed: %s $icon_url, got response code $status".printf(feed.getFeedID()));
-		return false;
+		return null;
 	}
 }
diff --git a/src/FeedReader.vala b/src/FeedReader.vala
index 5fdd7af2..29ea63ed 100644
--- a/src/FeedReader.vala
+++ b/src/FeedReader.vala
@@ -84,14 +84,6 @@ namespace FeedReader {
 					});
 				});
 
-				FeedReaderBackend.get_default().reloadFavIcons.connect(() => {
-					GLib.Idle.add(() => {
-						Logger.debug("FeedReader: reloadFavIcons");
-						ColumnView.get_default().reloadFavIcons();
-						return GLib.Source.REMOVE;
-					});
-				});
-
 				FeedReaderBackend.get_default().updateArticleList.connect(() => {
 					GLib.Idle.add(() => {
 						Logger.debug("FeedReader: updateArticleList");
diff --git a/src/Widgets/ArticleList/ArticleList.vala b/src/Widgets/ArticleList/ArticleList.vala
index 48d14909..8e174ccb 100644
--- a/src/Widgets/ArticleList/ArticleList.vala
+++ b/src/Widgets/ArticleList/ArticleList.vala
@@ -779,9 +779,4 @@ public class FeedReader.ArticleList : Gtk.Overlay {
 	{
 		m_currentList.emptyList();
 	}
-
-	public void reloadFavIcons()
-	{
-		m_currentList.reloadFavIcons();
-	}
 }
diff --git a/src/Widgets/ArticleList/ArticleListBox.vala b/src/Widgets/ArticleList/ArticleListBox.vala
index 1920b81a..67444bcf 100644
--- a/src/Widgets/ArticleList/ArticleListBox.vala
+++ b/src/Widgets/ArticleList/ArticleListBox.vala
@@ -662,15 +662,4 @@ public class FeedReader.ArticleListBox : Gtk.ListBox {
 		addRow(ArticleListBalance.NONE, false, false);
 		return true;
 	}
-
-	public void reloadFavIcons()
-	{
-		var children = this.get_children();
-		foreach(var row in children)
-		{
-			var tmpRow = row as ArticleRow;
-			if(tmpRow != null)
-				tmpRow.reloadFavIcon.begin();
-		}
-	}
 }
diff --git a/src/Widgets/ArticleRow.vala b/src/Widgets/ArticleRow.vala
index 667ce3b3..bf31b1f2 100644
--- a/src/Widgets/ArticleRow.vala
+++ b/src/Widgets/ArticleRow.vala
@@ -137,12 +137,7 @@ public class FeedReader.ArticleRow : Gtk.ListBoxRow {
 		m_marked_eventbox.leave_notify_event.connect(markedIconLeave);
 		m_marked_eventbox.button_press_event.connect(markedIconClicked);
 
-
 		m_icon = createFavIcon();
-		FavIconManager.get_default().ReloadFavIcon.connect(feed => {
-			if(m_article.getFeedID() == feed.getFeedID())
-				reloadFavIcon.begin();
-		});
 
 		icon_box.pack_start(m_icon, true, true, 0);
 		icon_box.pack_end(m_unread_eventbox, false, false, 10);
@@ -260,23 +255,20 @@ public class FeedReader.ArticleRow : Gtk.ListBoxRow {
 		return false;
 	}
 
-	public async void reloadFavIcon(Gtk.Image? inIcon = null)
-	{
-		Feed feed = DataBase.readOnly().read_feed(m_article.getFeedID());
-		var icon = yield FavIconManager.get_default().getIcon(feed);
-		if(icon != null)
-		{
-			if(inIcon == null)
-				m_icon.pixbuf = icon;
-			else
-				inIcon.pixbuf = icon;
-		}
-	}
-
 	private Gtk.Image createFavIcon()
 	{
 		var icon = new Gtk.Image.from_icon_name("feed-rss-symbolic", Gtk.IconSize.LARGE_TOOLBAR);
-		reloadFavIcon.begin(icon);
+
+		var manager = FavIconManager.get_default();
+		Feed feed = DataBase.readOnly().read_feed(m_article.getFeedID());
+		manager.getIcon.begin(feed, (obj, res) => {
+			var pixbuf = manager.getIcon.end(res);
+			if(pixbuf != null)
+			{
+				icon.pixbuf = pixbuf;
+			}
+		});
+
 		return icon;
 	}
 
diff --git a/src/Widgets/ColumnView.vala b/src/Widgets/ColumnView.vala
index 7f7078fb..0ae9aea3 100644
--- a/src/Widgets/ColumnView.vala
+++ b/src/Widgets/ColumnView.vala
@@ -517,10 +517,4 @@ public class FeedReader.ColumnView : Gtk.Paned {
 		m_article_view.clearContent();
 		m_feedList.clear();
 	}
-
-	public void reloadFavIcons()
-	{
-		m_articleList.reloadFavIcons();
-		m_feedList.reloadFavIcons();
-	}
 }
diff --git a/src/Widgets/FeedList.vala b/src/Widgets/FeedList.vala
index fa6ce6e7..ddaadc8c 100644
--- a/src/Widgets/FeedList.vala
+++ b/src/Widgets/FeedList.vala
@@ -1186,17 +1186,4 @@ public class FeedReader.feedList : Gtk.ScrolledWindow {
 
 		return false;
 	}
-
-	public void reloadFavIcons()
-	{
-		var FeedChildList = m_list.get_children();
-
-		foreach(Gtk.Widget row in FeedChildList)
-		{
-			var tmpRow = row as FeedRow;
-			if(tmpRow != null)
-				tmpRow.reloadFavIcon.begin();
-		}
-	}
-
 }
diff --git a/src/Widgets/FeedRow.vala b/src/Widgets/FeedRow.vala
index f8dc4890..540d77fd 100644
--- a/src/Widgets/FeedRow.vala
+++ b/src/Widgets/FeedRow.vala
@@ -44,10 +44,6 @@ public class FeedReader.FeedRow : Gtk.ListBoxRow {
 			var rowhight = 30;
 			m_box = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 0);
 			m_icon = createFavIcon();
-			FavIconManager.get_default().ReloadFavIcon.connect(feed => {
-				if(m_feed.getFeedID() == feed.getFeedID())
-					reloadFavIcon.begin();
-			});
 
 			m_icon.margin_start = level * 24;
 
@@ -151,30 +147,20 @@ public class FeedReader.FeedRow : Gtk.ListBoxRow {
 		}
 	}
 
-	public async void reloadFavIcon(Gtk.Image? inIcon = null)
-	{
-		var icon = yield FavIconManager.get_default().getIcon(m_feed);
-		if(icon == null)
-			return;
-
-		if(inIcon == null)
-		{
-			m_icon.pixbuf = icon;
-			m_icon.get_style_context().remove_class("fr-sidebar-symbolic");
-		}
-		else
-		{
-			inIcon.pixbuf = icon;
-			inIcon.get_style_context().remove_class("fr-sidebar-symbolic");
-		}
-	}
-
 	public Gtk.Image createFavIcon()
 	{
 		var icon = new Gtk.Image.from_icon_name("feed-rss-symbolic", Gtk.IconSize.LARGE_TOOLBAR);
 		icon.get_style_context().add_class("fr-sidebar-symbolic");
-		reloadFavIcon.begin(icon);
 
+		var manager = FavIconManager.get_default();
+		manager.getIcon.begin(m_feed, (obj, res) => {
+			var pixbuf = manager.getIcon.end(res);
+			if(pixbuf != null)
+			{
+				icon.pixbuf = pixbuf;
+				icon.get_style_context().remove_class("fr-sidebar-symbolic");
+			}
+		});
 		return icon;
 	}