all: add mobile (android/ios) supports (#9)

Author: changkun

.github/workflows/clipboard.yml

@@ -26,7 +26,7 @@ jobs:
       if: ${{ runner.os == 'Linux' }}
       run: |
         sudo apt update
-        sudo apt install -y xvfb libx11-dev
+        sudo apt install -y xvfb libx11-dev libegl1-mesa-dev libgles2-mesa-dev
         Xvfb :0 -screen 0 1024x768x24 > /dev/null 2>&1 &
         # Wait for Xvfb
         MAX_ATTEMPTS=120 # About 60 seconds

README.md

@@ -1,17 +1,18 @@
 # clipboard [![PkgGoDev](https://pkg.go.dev/badge/golang.design/x/clipboard)](https://pkg.go.dev/golang.design/x/clipboard) ![](https://changkun.de/urlstat?mode=github&repo=golang-design/clipboard) ![clipboard](https://github.com/golang-design/clipboard/workflows/clipboard/badge.svg?branch=main)
 
-cross platform clipboard package in Go
+Cross platform clipboard package in Go
 
 ```go
 import "golang.design/x/clipboard"
 ```
 
 ## Features
 
-- Cross platform supports: macOS, Linux (X11), and Windows
+- Cross platform supports: **macOS, Linux (X11), Windows, iOS, and Android**
 - Copy/paste UTF-8 text
-- Copy/paste PNG encoded images
+- Copy/paste PNG encoded images (Desktop-only)
 - Command `gclip` as a demo application
+- Mobile app `Gclip` as a demo application
 
 ## API Usage
 
@@ -109,9 +110,10 @@ accessing system clipboards, but here are a few details you might need to know.
 
 ### Dependency
 
-- macOS users: require Cgo, no dependency
-- Linux users: require X11 dev package. For instance, install `libx11-dev` or `xorg-dev` or `libX11-devel` to access X window system.
-- Windows users: no Cgo, no dependency
+- macOS: require Cgo, no dependency
+- Linux: require X11 dev package. For instance, install `libx11-dev` or `xorg-dev` or `libX11-devel` to access X window system.
+- Windows: no Cgo, no dependency
+- iOS/Android: collaborate with [`gomobile`](https://golang.org/x/mobile)
 
 ### Screenshot
 

clipboard_android.c

@@ -0,0 +1,80 @@
+// 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 && android
+
+#include <android/log.h>
+#include <jni.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define LOG_FATAL(...) __android_log_print(ANDROID_LOG_FATAL, \
+    "GOLANG.DESIGN/X/CLIPBOARD", __VA_ARGS__)
+
+static jmethodID find_method(JNIEnv *env, jclass clazz, const char *name, const char *sig) {
+	jmethodID m = (*env)->GetMethodID(env, clazz, name, sig);
+	if (m == 0) {
+		(*env)->ExceptionClear(env);
+		LOG_FATAL("cannot find method %s %s", name, sig);
+		return 0;
+	}
+	return m;
+}
+
+jobject get_clipboard(uintptr_t jni_env, uintptr_t ctx) {
+	JNIEnv *env = (JNIEnv*)jni_env;
+	jclass ctxClass = (*env)->GetObjectClass(env, (jobject)ctx);
+	jmethodID getSystemService = find_method(env, ctxClass, "getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;");
+
+	jstring service = (*env)->NewStringUTF(env, "clipboard");
+	jobject ret = (jobject)(*env)->CallObjectMethod(env, (jobject)ctx, getSystemService, service);
+	jthrowable err = (*env)->ExceptionOccurred(env);
+
+	if (err != NULL) {
+		LOG_FATAL("cannot find clipboard");
+		(*env)->ExceptionClear(env);
+		return NULL;
+	}
+	return ret;
+}
+
+char *clipboard_read_string(uintptr_t java_vm, uintptr_t jni_env, uintptr_t ctx) {
+	JNIEnv *env = (JNIEnv*)jni_env;
+	jobject mgr = get_clipboard(jni_env, ctx);
+	if (mgr == NULL) {
+		return NULL;
+	}
+
+	jclass mgrClass = (*env)->GetObjectClass(env, mgr);
+	jmethodID getText = find_method(env, mgrClass, "getText", "()Ljava/lang/CharSequence;");
+
+	jobject content = (jstring)(*env)->CallObjectMethod(env, mgr, getText);
+	if (content == NULL) {
+		return NULL;
+	}
+
+	jclass clzCharSequence = (*env)->GetObjectClass(env, content);
+	jmethodID toString = (*env)->GetMethodID(env, clzCharSequence, "toString", "()Ljava/lang/String;");
+	jobject s = (*env)->CallObjectMethod(env, content, toString);
+
+	const char *chars = (*env)->GetStringUTFChars(env, s, NULL);
+	char *copy = strdup(chars);
+	(*env)->ReleaseStringUTFChars(env, s, chars);
+	return copy;
+}
+
+void clipboard_write_string(uintptr_t java_vm, uintptr_t jni_env, uintptr_t ctx, char *str) {
+	JNIEnv *env = (JNIEnv*)jni_env;
+	jobject mgr = get_clipboard(jni_env, ctx);
+	if (mgr == NULL) {
+		return;
+	}
+
+	jclass mgrClass = (*env)->GetObjectClass(env, mgr);
+	jmethodID setText = find_method(env, mgrClass, "setText", "(Ljava/lang/CharSequence;)V");
+
+	(*env)->CallVoidMethod(env, mgr, setText, (*env)->NewStringUTF(env, str));
+}

clipboard_android.go

@@ -0,0 +1,97 @@
+// 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 && android
+
+package clipboard
+
+/*
+#cgo LDFLAGS: -landroid -llog
+
+#include <stdlib.h>
+char *clipboard_read_string(uintptr_t java_vm, uintptr_t jni_env, uintptr_t ctx);
+void clipboard_write_string(uintptr_t java_vm, uintptr_t jni_env, uintptr_t ctx, char *str);
+
+*/
+import "C"
+import (
+	"bytes"
+	"context"
+	"errors"
+	"time"
+	"unsafe"
+
+	"golang.org/x/mobile/app"
+)
+
+func read(t Format) (buf []byte, err error) {
+	switch t {
+	case FmtText:
+		s := ""
+		app.RunOnJVM(func(vm, env, ctx uintptr) error {
+			cs := C.clipboard_read_string(C.uintptr_t(vm), C.uintptr_t(env), C.uintptr_t(ctx))
+			if cs == nil {
+				return nil
+			}
+
+			s = C.GoString(cs)
+			C.free(unsafe.Pointer(cs))
+			return nil
+		})
+		return []byte(s), nil
+	case FmtImage:
+		return nil, errors.New("unsupported")
+	default:
+		return nil, errors.New("unsupported")
+	}
+}
+
+// write writes the given data to clipboard and
+// returns true if success or false if failed.
+func write(t Format, buf []byte) (<-chan struct{}, error) {
+	done := make(chan struct{}, 1)
+	switch t {
+	case FmtText:
+		cs := C.CString(string(buf))
+		defer C.free(unsafe.Pointer(cs))
+
+		app.RunOnJVM(func(vm, env, ctx uintptr) error {
+			C.clipboard_write_string(C.uintptr_t(vm), C.uintptr_t(env), C.uintptr_t(ctx), cs)
+			done <- struct{}{}
+			return nil
+		})
+		return done, nil
+	case FmtImage:
+		return nil, errors.New("unsupported")
+	default:
+		return nil, errors.New("unsupported")
+	}
+}
+
+func watch(ctx context.Context, t Format) <-chan []byte {
+	recv := make(chan []byte, 1)
+	ti := time.NewTicker(time.Second)
+	last := Read(t)
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				close(recv)
+				return
+			case <-ti.C:
+				b := Read(t)
+				if b == nil {
+					continue
+				}
+				if bytes.Compare(last, b) != 0 {
+					recv <- b
+					last = b
+				}
+			}
+		}
+	}()
+	return recv
+}

clipboard_darwin.go

@@ -4,8 +4,7 @@
 //
 // Written by Changkun Ou <changkun.de>
 
-//go:build darwin
-// +build darwin
+//go:build darwin && !ios
 
 package clipboard
 

clipboard_darwin.m

@@ -4,6 +4,8 @@
 //
 // Written by Changkun Ou <changkun.de>
 
+//go:build darwin && !ios
+
 // Interact with NSPasteboard using Objective-C
 // https://developer.apple.com/documentation/appkit/nspasteboard?language=objc
 

clipboard_ios.go

@@ -0,0 +1,79 @@
+// 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 ios
+
+package clipboard
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Foundation -framework UIKit -framework MobileCoreServices
+
+#import <stdlib.h>
+void clipboard_write_string(char *s);
+char *clipboard_read_string();
+*/
+import "C"
+import (
+	"bytes"
+	"context"
+	"errors"
+	"time"
+	"unsafe"
+)
+
+func read(t Format) (buf []byte, err error) {
+	switch t {
+	case FmtText:
+		return []byte(C.GoString(C.clipboard_read_string())), nil
+	case FmtImage:
+		return nil, errors.New("unimplemented")
+	default:
+		return nil, errors.New("unimplemented")
+	}
+}
+
+// SetContent sets the clipboard content for iOS
+func write(t Format, buf []byte) (<-chan struct{}, error) {
+	done := make(chan struct{}, 1)
+	switch t {
+	case FmtText:
+		cs := C.CString(string(buf))
+		defer C.free(unsafe.Pointer(cs))
+
+		C.clipboard_write_string(cs)
+		return done, nil
+	case FmtImage:
+		return nil, errors.New("unimplemented")
+	default:
+		return nil, errors.New("unimplemented")
+	}
+}
+
+func watch(ctx context.Context, t Format) <-chan []byte {
+	recv := make(chan []byte, 1)
+	ti := time.NewTicker(time.Second)
+	last := Read(t)
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				close(recv)
+				return
+			case <-ti.C:
+				b := Read(t)
+				if b == nil {
+					continue
+				}
+				if bytes.Compare(last, b) != 0 {
+					recv <- b
+					last = b
+				}
+			}
+		}
+	}()
+	return recv
+}

clipboard_ios.m

@@ -0,0 +1,20 @@
+// 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 ios
+
+#import <UIKit/UIKit.h>
+#import <MobileCoreServices/MobileCoreServices.h>
+
+void clipboard_write_string(char *s) {
+    NSString *value = [NSString stringWithUTF8String:s];
+    [[UIPasteboard generalPasteboard] setString:value];
+}
+
+char *clipboard_read_string() {
+    NSString *str = [[UIPasteboard generalPasteboard] string];
+    return (char *)[str UTF8String];
+}

clipboard_linux.c

@@ -4,6 +4,8 @@
 //
 // Written by Changkun Ou <changkun.de>
 
+//go:build linux && !android
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdint.h>

clipboard_linux.go

@@ -4,8 +4,7 @@
 //
 // Written by Changkun Ou <changkun.de>
 
-// +build linux
-//go:build linux
+//go:build linux && !android
 
 package clipboard