make shell providers pluggable

terminus-terminal/src/shells/gitBash.ts

@@ -0,0 +1,49 @@
+import * as path from 'path'
+import { Injectable } from '@angular/core'
+import { HostAppService, Platform } from 'terminus-core'
+
+import { ShellProvider, IShell } from '../api'
+
+let Registry = null
+try {
+    Registry = require('winreg')
+} catch (_) { } // tslint:disable-line no-empty
+
+@Injectable()
+export class GitBashShellProvider extends ShellProvider {
+    constructor (
+        private hostApp: HostAppService,
+    ) {
+        super()
+    }
+
+    async provide (): Promise<IShell[]> {
+        if (this.hostApp.platform !== Platform.Windows) {
+            return []
+        }
+
+        let gitBashPath = await new Promise<string>(resolve => {
+            let reg = new Registry({ hive: Registry.HKLM, key: '\\Software\\GitForWindows' })
+            reg.get('InstallPath', (err, item) => {
+                if (err) {
+                    resolve(null)
+                    return
+                }
+                resolve(item.value)
+            })
+        })
+
+        if (!gitBashPath) {
+            return []
+        }
+
+        return [{
+            id: 'git-bash',
+            name: 'Git-Bash',
+            command: path.join(gitBashPath, 'bin', 'bash.exe'),
+            env: {
+                TERM: 'cygwin',
+            }
+        }]
+    }
+}