From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Sun, 2 Oct 2016 15:28:37 +0000 (+0200)
Subject: tests: Add async generator example to cover an edge case
X-Git-Tag: 0.35.1~120
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6e89b7b5d8112925cb8f07234a85ea1dba1e32e6;p=thirdparty%2Fvala.git

tests: Add async generator example to cover an edge case

https://bugzilla.gnome.org/show_bug.cgi?id=763345
---

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 0fd49d9fa..8ff0f3da3 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -208,6 +208,7 @@ TESTS = \
 	asynchronous/bug661961.vala \
 	asynchronous/bug742621.vala \
 	asynchronous/closures.vala \
+	asynchronous/generator.vala \
 	asynchronous/yield.vala \
 	dbus/basic-types.test \
 	dbus/arrays.test \
diff --git a/tests/asynchronous/generator.vala b/tests/asynchronous/generator.vala
new file mode 100644
index 000000000..f31e12a42
--- /dev/null
+++ b/tests/asynchronous/generator.vala
@@ -0,0 +1,60 @@
+// This is based on Luca Bruno's Generator. It illustrates using async methods
+// to emulate a generator style of iterator coding. Note that this runs fine
+// without a main loop.
+
+abstract class Generator<G> {
+	bool consumed;
+	unowned G value;
+	SourceFunc callback;
+
+	public Generator () {
+		helper.begin ();
+	}
+
+	async void helper () {
+		yield generate ();
+		consumed = true;
+	}
+
+	protected abstract async void generate ();
+
+	protected async void feed (G value) {
+		this.value = value;
+		this.callback = feed.callback;
+		yield;
+	}
+
+	public bool next () {
+		return !consumed;
+	}
+
+	public G get () {
+		var result = value;
+		callback ();
+		return result;
+	}
+
+	public Generator<G> iterator () {
+		return this;
+	}
+}
+
+class IntGenerator : Generator<int> {
+	protected override async void generate () {
+		for (int i = 0; i < 10; i++) {
+			 if (i % 2 == 0)
+			 	yield feed (i);
+		}
+	}
+}
+
+void main () {
+	var gen = new IntGenerator ();
+	string result = "";
+
+	foreach (var item in gen)
+		result += "%i ".printf (item);
+
+	assert (result == "0 2 4 6 8 ");
+}
+