Make Clipboard Plugin API work in FireFox

Signed-off-by: Artem Zatsarynnyi <azatsary@redhat.com>

packages/core/src/browser/browser-clipboard-service.ts

@@ -14,37 +14,98 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
-import { injectable } from 'inversify';
+import { injectable, inject } from 'inversify';
+import { isFirefox } from './browser';
 import { ClipboardService } from './clipboard-service';
+import { ILogger } from '../common/logger';
+import { MessageService } from '../common/message-service';
 
 export interface NavigatorClipboard {
     readText(): Promise<string>;
     writeText(value: string): Promise<void>;
 }
+export interface PermissionStatus {
+    state: 'granted' | 'prompt' | 'denied'
+}
 export interface NavigatorPermissions {
-    query(options: { name: string }): Promise<{ state: 'granted' | 'prompt' | 'denied' }>
+    query(options: { name: string }): Promise<PermissionStatus>
 }
 
 @injectable()
 export class BrowserClipboardService implements ClipboardService {
 
+    @inject(MessageService)
+    protected readonly messageService: MessageService;
+
+    @inject(ILogger)
+    protected readonly logger: ILogger;
+
     async readText(): Promise<string> {
-        if ('permissions' in navigator && 'clipboard' in navigator) {
-            const result = await (<NavigatorPermissions>navigator['permissions']).query({ name: 'clipboard-read' });
-            if (result.state === 'granted' || result.state === 'prompt') {
-                return (<NavigatorClipboard>navigator['clipboard']).readText();
+        let permission;
+        try {
+            permission = await this.queryPermission('clipboard-read');
+        } catch (e) {
+            this.logger.error('Failed checking a clipboard-read permission.', e);
+            // in FireFox, Clipboard API isn't gated with the permissions
+            try {
+                return await this.getClipboardAPI().readText();
+            } catch (e) {
+                this.logger.error('Failed reading clipboard content.', e);
+                if (isFirefox) {
+                    this.messageService.warn(`Clipboard API is not available.
+                    It can be enabled by 'dom.events.testing.asyncClipboard' preference on 'about:config' page. Then reload Theia.
+                    Note, it will allow FireFox getting full access to the system clipboard.`);
+                }
+                throw new Error('Failed reading clipboard content.');
             }
         }
-        return '';
+        if (permission.state === 'denied') {
+            // most likely, the user intentionally denied the access
+            this.messageService.error("Access to the clipboard is denied. Check your browser's permission.");
+            throw new Error('Access to the clipboard is denied.');
+        }
+        return this.getClipboardAPI().readText();
     }
 
     async writeText(value: string): Promise<void> {
-        if ('permissions' in navigator && 'clipboard' in navigator) {
-            const result = await (<NavigatorPermissions>navigator['permissions']).query({ name: 'clipboard-write' });
-            if (result.state === 'granted' || result.state === 'prompt') {
-                return (<NavigatorClipboard>navigator['clipboard']).writeText(value);
+        let permission;
+        try {
+            permission = await this.queryPermission('clipboard-write');
+        } catch (e) {
+            this.logger.error('Failed checking a clipboard-write permission.', e);
+            // in FireFox, Clipboard API isn't gated with the permissions
+            try {
+                await this.getClipboardAPI().writeText(value);
+                return;
+            } catch (e) {
+                this.logger.error('Failed writing to the clipboard.', e);
+                if (isFirefox) {
+                    this.messageService.warn(`Clipboard API is not available.
+                    It can be enabled by 'dom.events.testing.asyncClipboard' preference on 'about:config' page. Then reload Theia.
+                    Note, it will allow FireFox getting full access to the system clipboard.`);
+                }
+                throw new Error('Failed writing the the clipboard.');
             }
         }
+        if (permission.state === 'denied') {
+            // most likely, the user intentionally denied the access
+            this.messageService.error("Access to the clipboard is denied. Check your browser's permission.");
+            throw new Error('Access to the clipboard is denied.');
+        }
+        return this.getClipboardAPI().writeText(value);
     }
 
+    protected async queryPermission(name: string): Promise<PermissionStatus> {
+        if ('permissions' in navigator) {
+            return (<NavigatorPermissions>navigator['permissions']).query({ name: name });
+        }
+        throw new Error('Permissions API unavailable');
+    }
+
+    protected getClipboardAPI(): NavigatorClipboard {
+        if ('clipboard' in navigator) {
+            return (<NavigatorClipboard>navigator['clipboard']);
+        }
+        throw new Error('Async Clipboard API unavailable');
+    }
 }