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一、chrome.system.storage

您可以使用 chrome.system.storage API 查询存储设备信息，并在连接和分离可移动存储设备时收到通知。

权限

system.storage

类型

EjectDeviceResultCode

枚举

"success"
移除命令成功执行 - 应用可以提示用户移除设备。

"in_use"
设备正被其他应用使用。移除失败；在其他应用完成对设备的操作之前，用户不得移除设备。

"no_such_device"
没有已知的此类设备。

"failure"
移除命令失败。

StorageAvailableCapacityInfo

属性

• availableCapacity

  number

  存储设备的可用容量（以字节为单位）。

• id

  字符串

  getAvailableCapacity 函数参数 id 的 id。

StorageUnitInfo

属性

• 容量

  number

  存储空间总量（以字节为单位）。

• id

  字符串

  唯一标识存储设备的临时 ID。此 ID 在单个应用的同一运行时内保持不变。它不是应用的不同运行之间或不同应用之间的永久性标识符。

• name

  字符串

  存储单元的名称。

• 类型

  StorageUnitType

  存储单元的媒体类型。

StorageUnitType

枚举

"fixed"
存储具有固定介质，例如或 SSD。

"removable"
存储空间可移动，例如U 盘。

"unknown"
存储类型未知。

方法

ejectDevice()

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chrome.system.storage.ejectDevice(id: string,callback?: function,
)

弹出可移动存储设备。

参数

• id

  字符串

• callback

  函数（可选）

  callback 参数如下所示：

  (result: EjectDeviceResultCode) => void

chrome.system.storage  |  API  |  Chrome for Developers

二、chrome.system.storage api接口定义c++：

1、system_storage.idl

extensions\common\api\system_storage.idl

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.// Use the <code>chrome.system.storage</code> API to query storage device
// information and be notified when a removable storage device is attached and
// detached.
namespace system.storage {enum StorageUnitType {// The storage has fixed media, e.g. hard disk or SSD.fixed,// The storage is removable, e.g. USB flash drive.removable,// The storage type is unknown.unknown};dictionary StorageUnitInfo {// The transient ID that uniquely identifies the storage device.// This ID will be persistent within the same run of a single application.// It will not be a persistent identifier between different runs of an// application, or between different applications.DOMString id;// The name of the storage unit.DOMString name;// The media type of the storage unit.StorageUnitType type;// The total amount of the storage space, in bytes.double capacity;};dictionary StorageAvailableCapacityInfo {// A copied |id| of getAvailableCapacity function parameter |id|.DOMString id;// The available capacity of the storage device, in bytes.double availableCapacity;};[inline_doc] enum EjectDeviceResultCode {// The ejection command is successful -- the application can prompt the user// to remove the device.success,// The device is in use by another application. The ejection did not// succeed; the user should not remove the device until the other// application is done with the device.in_use,// There is no such device known.no_such_device,// The ejection command failed.failure};callback EjectDeviceCallback = void (EjectDeviceResultCode result);callback StorageInfoCallback = void (StorageUnitInfo[] info);callback GetAvailableCapacityCallback = void (StorageAvailableCapacityInfo info);interface Functions {// Get the storage information from the system. The argument passed to the// callback is an array of StorageUnitInfo objects.[supportsPromises] static void getInfo(StorageInfoCallback callback);// Ejects a removable storage device.[supportsPromises] static void ejectDevice(DOMString id,EjectDeviceCallback callback);// Get the available capacity of a specified |id| storage device.// The |id| is the transient device ID from StorageUnitInfo.[supportsPromises] static void getAvailableCapacity(DOMString id,GetAvailableCapacityCallback callback);};interface Events {// Fired when a new removable storage is attached to the system.static void onAttached(StorageUnitInfo info);// Fired when a removable storage is detached from the system.static void onDetached(DOMString id);};};

2、system_storage.idl 自动生成c++文件：

out\Debug\gen\extensions\common\api\system_storage.cc

out\Debug\gen\extensions\common\api\system_storage.h

3、chrome.system.storage api c++定义

extensions\browser\api\system_storage\system_storage_api.h

extensions\browser\api\system_storage\system_storage_api.cc

namespace extensions {// Implementation of the systeminfo.storage.get API. It is an asynchronous
// call relative to browser UI thread.
class SystemStorageGetInfoFunction : public ExtensionFunction {public:DECLARE_EXTENSION_FUNCTION("system.storage.getInfo", SYSTEM_STORAGE_GETINFO)SystemStorageGetInfoFunction() = default;private:~SystemStorageGetInfoFunction() override = default;// ExtensionFunction:ResponseAction Run() override;void OnGetStorageInfoCompleted(bool success);
};class SystemStorageEjectDeviceFunction : public ExtensionFunction {public:DECLARE_EXTENSION_FUNCTION("system.storage.ejectDevice",SYSTEM_STORAGE_EJECTDEVICE)protected:~SystemStorageEjectDeviceFunction() override = default;// ExtensionFunction:ResponseAction Run() override;private:void OnStorageMonitorInit(const std::string& transient_device_id);// Eject device request handler.void HandleResponse(storage_monitor::StorageMonitor::EjectStatus status);
};class SystemStorageGetAvailableCapacityFunction : public ExtensionFunction {public:DECLARE_EXTENSION_FUNCTION("system.storage.getAvailableCapacity",SYSTEM_STORAGE_GETAVAILABLECAPACITY)SystemStorageGetAvailableCapacityFunction();private:void OnStorageMonitorInit(const std::string& transient_id);void OnQueryCompleted(const std::string& transient_id,double available_capacity);~SystemStorageGetAvailableCapacityFunction() override;// ExtensionFunction:ResponseAction Run() override;scoped_refptr<base::SequencedTaskRunner> query_runner_;
};}  // namespace extensions