gecko-dev/dom/system/gonk/VolumeCommand.h

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5.6 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_system_volumecommand_h__
#define mozilla_system_volumecommand_h__
#include "nsString.h"
#include "nsISupportsImpl.h"
#include "mozilla/RefPtr.h"
#include <algorithm>
#include <vold/ResponseCode.h>
namespace mozilla {
namespace system {
class Volume;
class VolumeCommand;
/***************************************************************************
*
* The VolumeResponseCallback class is an abstract base class. The ResponseReceived
* method will be called for each response received.
*
* Depending on the command, there may be multiple responses for the
* command. Done() will return true if this is the last response.
*
* The responses from vold are all of the form:
*
* <ResponseCode> <String>
*
* Valid Response codes can be found in the vold/ResponseCode.h header.
*
***************************************************************************/
class VolumeResponseCallback
{
protected:
virtual ~VolumeResponseCallback() {}
public:
NS_INLINE_DECL_REFCOUNTING(VolumeResponseCallback)
VolumeResponseCallback()
: mResponseCode(0), mPending(false) {}
bool Done() const
{
// Response codes from the 200, 400, and 500 series all indicated that
// the command has completed.
return (mResponseCode >= ResponseCode::CommandOkay)
&& (mResponseCode < ResponseCode::UnsolicitedInformational);
}
bool WasSuccessful() const
{
return mResponseCode == ResponseCode::CommandOkay;
}
bool IsPending() const { return mPending; }
int ResponseCode() const { return mResponseCode; }
const nsCString &ResponseStr() const { return mResponseStr; }
protected:
virtual void ResponseReceived(const VolumeCommand* aCommand) = 0;
private:
friend class VolumeCommand; // Calls HandleResponse and SetPending
void HandleResponse(const VolumeCommand* aCommand,
int aResponseCode,
nsACString& aResponseStr)
{
mResponseCode = aResponseCode;
#if ANDROID_VERSION >= 17
// There's a sequence number here that we don't care about
// We expect it to be 0. See VolumeCommand::SetCmd
mResponseStr = Substring(aResponseStr, 2);
#else
mResponseStr = aResponseStr;
#endif
if (mResponseCode >= ResponseCode::CommandOkay) {
// This is a final response.
mPending = false;
}
ResponseReceived(aCommand);
}
void SetPending(bool aPending) { mPending = aPending; }
int mResponseCode; // The response code parsed from vold
nsCString mResponseStr; // The rest of the line.
bool mPending; // Waiting for response?
};
/***************************************************************************
*
* The VolumeCommand class is an abstract base class used to encapsulate
* volume commands send to vold.
*
* See VolumeManager.h for a list of the volume commands.
*
* Commands sent to vold need an explicit null character so we add one
* to the command to ensure that it's included in the length.
*
* All of these commands are asynchronous in nature, and the
* ResponseReceived callback will be called when a response is available.
*
***************************************************************************/
class VolumeCommand
{
protected:
virtual ~VolumeCommand() {}
public:
NS_INLINE_DECL_REFCOUNTING(VolumeCommand)
VolumeCommand(VolumeResponseCallback* aCallback)
: mBytesConsumed(0),
mCallback(aCallback)
{
SetCmd(NS_LITERAL_CSTRING(""));
}
VolumeCommand(const nsACString& aCommand, VolumeResponseCallback* aCallback)
: mBytesConsumed(0),
mCallback(aCallback)
{
SetCmd(aCommand);
}
void SetCmd(const nsACString& aCommand)
{
mCmd.Truncate();
#if ANDROID_VERSION >= 17
// JB requires a sequence number at the beginning of messages.
// It doesn't matter what we use, so we use 0.
mCmd = "0 ";
#endif
mCmd.Append(aCommand);
// Add a null character. We want this to be included in the length since
// vold uses it to determine the end of the command.
mCmd.Append('\0');
}
const char* CmdStr() const { return mCmd.get(); }
const char* Data() const { return mCmd.Data() + mBytesConsumed; }
size_t BytesConsumed() const { return mBytesConsumed; }
size_t BytesRemaining() const
{
return mCmd.Length() - std::min(mCmd.Length(), mBytesConsumed);
}
void ConsumeBytes(size_t aNumBytes)
{
mBytesConsumed += std::min(BytesRemaining(), aNumBytes);
}
private:
friend class VolumeManager; // Calls SetPending & HandleResponse
void SetPending(bool aPending)
{
if (mCallback) {
mCallback->SetPending(aPending);
}
}
void HandleResponse(int aResponseCode, nsACString& aResponseStr)
{
if (mCallback) {
mCallback->HandleResponse(this, aResponseCode, aResponseStr);
}
}
nsCString mCmd; // Command being sent
size_t mBytesConsumed; // How many bytes have been sent
// Called when a response to the command is received.
RefPtr<VolumeResponseCallback> mCallback;
};
class VolumeActionCommand : public VolumeCommand
{
public:
VolumeActionCommand(Volume* aVolume, const char* aAction,
const char* aExtraArgs, VolumeResponseCallback* aCallback);
private:
RefPtr<Volume> mVolume;
};
class VolumeListCommand : public VolumeCommand
{
public:
VolumeListCommand(VolumeResponseCallback* aCallback);
};
} // system
} // mozilla
#endif // mozilla_system_volumecommand_h__