all: improve error message when CGO_ENABLED=0

.github/workflows/hotkey.yml

@@ -48,6 +48,17 @@ jobs:
         stable: 'false'
         go-version: '1.17.x'
 
-    - name: Run Tests
+    - name: Run Tests with CGO_ENABLED=1
+      if: ${{ runner.os == 'Linux' || runner.os == 'macOS'}}
       run: |
-        go test -v -covermode=atomic ./...
+        CGO_ENABLED=1 go test -v -covermode=atomic .
+
+    - name: Run Tests with CGO_ENABLED=0
+      if: ${{ runner.os == 'Linux' || runner.os == 'macOS'}}
+      run: |
+        CGO_ENABLED=0 go test -v -covermode=atomic .
+
+    - name: Run Tests on Windows
+      if: ${{ runner.os == 'Windows'}}
+      run: |
+        go test -v -covermode=atomic .

go.mod

@@ -3,6 +3,6 @@ module golang.design/x/hotkey
 go 1.17
 
 require (
-	golang.design/x/mainthread v0.2.1
+	golang.design/x/mainthread v0.3.0
 	golang.org/x/sys v0.0.0-20210122093101-04d7465088b8 // indirect
 )

go.sum

@@ -1,5 +1,5 @@
-golang.design/x/mainthread v0.2.1 h1:IUGVW1acDfKoQtFeeS/RD/YYiKK8jxwkJXIQuKuL+ig=
-golang.design/x/mainthread v0.2.1/go.mod h1:vYX7cF2b3pTJMGM/hc13NmN6kblKnf4/IyvHeu259L0=
+golang.design/x/mainthread v0.3.0 h1:UwFus0lcPodNpMOGoQMe87jSFwbSsEY//CA7yVmu4j8=
+golang.design/x/mainthread v0.3.0/go.mod h1:vYX7cF2b3pTJMGM/hc13NmN6kblKnf4/IyvHeu259L0=
 golang.org/x/sys v0.0.0-20201022201747-fb209a7c41cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210122093101-04d7465088b8 h1:de2yTH1xuxjmGB7i6Z5o2z3RCHVa0XlpSZzjd8Fe6bE=
 golang.org/x/sys v0.0.0-20210122093101-04d7465088b8/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

hotkey.go

@@ -111,6 +111,7 @@ func newEventChan() (chan<- Event, <-chan Event) {
 			for len(q) > 0 {
 				select {
 				case out <- q[0]:
+					q[0] = Event{}
 					q = q[1:]
 				case e, ok := <-in:
 					if ok {

hotkey_darwin_test.go

@@ -4,7 +4,7 @@
 //
 // Written by Changkun Ou <changkun.de>
 
-//go:build darwin
+//go:build darwin && cgo
 
 package hotkey_test
 

hotkey_linux.c

@@ -11,11 +11,15 @@
 #include <X11/Xutil.h>
 
 int displayTest() {
-	Display* d = XOpenDisplay(0);
+	Display* d = NULL;
+	for (int i = 0; i < 42; i++) {
+		d = XOpenDisplay(0);
+		if (d == NULL) continue;
+		break;
+	}
 	if (d == NULL) {
 		return -1;
 	}
-	XCloseDisplay(d);
 	return 0;
 }
 

hotkey_linux_test.go

@@ -4,7 +4,7 @@
 //
 // Written by Changkun Ou <changkun.de>
 
-//go:build linux
+//go:build linux && cgo
 
 package hotkey_test
 

hotkey_nocgo.go

@@ -0,0 +1,31 @@
+// Copyright 2021 The golang.design Initiative Authors.
+// All rights reserved. Use of this source code is governed
+// by a MIT license that can be found in the LICENSE file.
+//
+// Written by Changkun Ou <changkun.de>
+
+//go:build !windows && !cgo
+
+package hotkey
+
+import "context"
+
+// Modifier represents a modifier
+type Modifier uint32
+
+// Key represents a key.
+type Key uint8
+
+func (hk *Hotkey) register() error {
+	panic("hotkey: cannot use when CGO_ENABLED=0")
+}
+
+// unregister deregisteres a system hotkey.
+func (hk *Hotkey) unregister() {
+	panic("hotkey: cannot use when CGO_ENABLED=0")
+}
+
+// handle handles the hotkey event loop.
+func (hk *Hotkey) handle(ctx context.Context) {
+	panic("hotkey: cannot use when CGO_ENABLED=0")
+}

hotkey_nocgo_test.go

@@ -0,0 +1,29 @@
+// Copyright 2021 The golang.design Initiative Authors.
+// All rights reserved. Use of this source code is governed
+// by a MIT license that can be found in the LICENSE file.
+//
+// Written by Changkun Ou <changkun.de>
+
+//go:build (linux || darwin) && !cgo
+
+package hotkey_test
+
+import (
+	"testing"
+
+	"golang.design/x/hotkey"
+)
+
+// TestHotkey should always run success.
+// This is a test to run and for manually testing, registered combination:
+// Ctrl+Alt+A (Ctrl+Mod2+Mod4+A on Linux)
+func TestHotkey(t *testing.T) {
+	defer func() {
+		if r := recover(); r != nil {
+			return
+		}
+		t.Fatalf("expect to fail when CGO_ENABLED=0")
+	}()
+
+	hotkey.Register([]hotkey.Modifier{}, hotkey.Key(0))
+}

vendor/golang.design/x/mainthread/.gitignore

@@ -0,0 +1,15 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/

vendor/golang.design/x/mainthread/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Changkun Ou <contact@changkun.de>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/golang.design/x/mainthread/README.md

@@ -0,0 +1,106 @@
+# mainthread [![PkgGoDev](https://pkg.go.dev/badge/golang.design/x/mainthread)](https://pkg.go.dev/golang.design/x/mainthread) ![mainthread](https://github.com/golang-design/mainthread/workflows/mainthread/badge.svg?branch=main) ![](https://changkun.de/urlstat?mode=github&repo=golang-design/mainthread)
+
+schedule functions to run on the main thread
+
+```go
+import "golang.design/x/mainthread"
+```
+
+## Features
+
+- Main thread scheduling
+- Schedule functions without memory allocation
+
+## API Usage
+
+Package mainthread offers facilities to schedule functions
+on the main thread. To use this package properly, one must
+call `mainthread.Init` from the main package. For example:
+
+```go
+package main
+
+import "golang.design/x/mainthread"
+
+func main() { mainthread.Init(fn) }
+
+// fn is the actual main function
+func fn() {
+	// ... do stuff ...
+
+	// mainthread.Call returns when f1 returns. Note that if f1 blocks
+	// it will also block the execution of any subsequent calls on the
+	// main thread.
+	mainthread.Call(f1)
+
+	// ... do stuff ...
+
+
+	// mainthread.Go returns immediately and f2 is scheduled to be
+	// executed in the future.
+	mainthread.Go(f2)
+
+	// ... do stuff ...
+}
+
+func f1() { ... }
+func f2() { ... }
+```
+
+If the given function triggers a panic, and called via `mainthread.Call`,
+then the panic will be propagated to the same goroutine. One can capture
+that panic, when possible:
+
+```go
+defer func() {
+	if r := recover(); r != nil {
+		println(r)
+	}
+}()
+
+mainthread.Call(func() { ... }) // if panic
+```
+
+If the given function triggers a panic, and called via `mainthread.Go`,
+then the panic will be cached internally, until a call to the `Error()` method:
+
+```go
+mainthread.Go(func() { ... }) // if panics
+
+// ... do stuff ...
+
+if err := mainthread.Error(); err != nil { // can be captured here.
+	println(err)
+}
+```
+
+Note that a panic happens before `mainthread.Error()` returning the
+panicked error. If one needs to guarantee `mainthread.Error()` indeed
+captured the panic, a dummy function can be used as synchornization:
+
+```go
+mainthread.Go(func() { panic("die") })	// if panics
+mainthread.Call(func() {}) 				// for execution synchronization
+err := mainthread.Error()				// err must be non-nil
+```
+
+
+It is possible to cache up to a maximum of 42 panicked errors.
+More errors are ignored.
+
+## When do you need this package?
+
+Read this to learn more about the design purpose of this package:
+https://golang.design/research/zero-alloc-call-sched/
+
+## Who is using this package?
+
+The initial purpose of building this package is to support writing
+graphical applications in Go. To know projects that are using this
+package, check our [wiki](https://github.com/golang-design/mainthread/wiki)
+page.
+
+
+## License
+
+MIT | © 2021 The golang.design Initiative Authors, written by [Changkun Ou](https://changkun.de).