1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/netwerk/base/src/nsBaseContentStream.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,82 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsBaseContentStream_h__
1.10 +#define nsBaseContentStream_h__
1.11 +
1.12 +#include "nsIAsyncInputStream.h"
1.13 +#include "nsIEventTarget.h"
1.14 +#include "nsCOMPtr.h"
1.15 +
1.16 +//-----------------------------------------------------------------------------
1.17 +// nsBaseContentStream is designed to be subclassed with the intention of being
1.18 +// used to satisfy the nsBaseChannel::OpenContentStream method.
1.19 +//
1.20 +// The subclass typically overrides the default Available, ReadSegments and
1.21 +// CloseWithStatus methods. By default, Read is implemented in terms of
1.22 +// ReadSegments, and Close is implemented in terms of CloseWithStatus. If
1.23 +// CloseWithStatus is overriden, then the subclass will usually want to call
1.24 +// the base class' CloseWithStatus method before returning.
1.25 +//
1.26 +// If the stream is non-blocking, then readSegments may return the exception
1.27 +// NS_BASE_STREAM_WOULD_BLOCK if there is no data available and the stream is
1.28 +// not at the "end-of-file" or already closed. This error code must not be
1.29 +// returned from the Available implementation. When the caller receives this
1.30 +// error code, he may choose to call the stream's AsyncWait method, in which
1.31 +// case the base stream will have a non-null PendingCallback. When the stream
1.32 +// has data or encounters an error, it should be sure to dispatch a pending
1.33 +// callback if one exists (see DispatchCallback). The implementation of the
1.34 +// base stream's CloseWithStatus (and Close) method will ensure that any
1.35 +// pending callback is dispatched. It is the responsibility of the subclass
1.36 +// to ensure that the pending callback is dispatched when it wants to have its
1.37 +// ReadSegments method called again.
1.38 +
1.39 +class nsBaseContentStream : public nsIAsyncInputStream
1.40 +{
1.41 +public:
1.42 + NS_DECL_THREADSAFE_ISUPPORTS
1.43 + NS_DECL_NSIINPUTSTREAM
1.44 + NS_DECL_NSIASYNCINPUTSTREAM
1.45 +
1.46 + nsBaseContentStream(bool nonBlocking)
1.47 + : mStatus(NS_OK)
1.48 + , mNonBlocking(nonBlocking) {
1.49 + }
1.50 +
1.51 + nsresult Status() { return mStatus; }
1.52 + bool IsNonBlocking() { return mNonBlocking; }
1.53 + bool IsClosed() { return NS_FAILED(mStatus); }
1.54 +
1.55 + // Called to test if the stream has a pending callback.
1.56 + bool HasPendingCallback() { return mCallback != nullptr; }
1.57 +
1.58 + // The current dispatch target (may be null) for the pending callback if any.
1.59 + nsIEventTarget *CallbackTarget() { return mCallbackTarget; }
1.60 +
1.61 + // Called to dispatch a pending callback. If there is no pending callback,
1.62 + // then this function does nothing. Pass true to this function to cause the
1.63 + // callback to occur asynchronously; otherwise, the callback will happen
1.64 + // before this function returns.
1.65 + void DispatchCallback(bool async = true);
1.66 +
1.67 + // Helper function to make code more self-documenting.
1.68 + void DispatchCallbackSync() { DispatchCallback(false); }
1.69 +
1.70 +protected:
1.71 + virtual ~nsBaseContentStream() {}
1.72 +
1.73 +private:
1.74 + // Called from the base stream's AsyncWait method when a pending callback
1.75 + // is installed on the stream.
1.76 + virtual void OnCallbackPending() {}
1.77 +
1.78 +private:
1.79 + nsCOMPtr<nsIInputStreamCallback> mCallback;
1.80 + nsCOMPtr<nsIEventTarget> mCallbackTarget;
1.81 + nsresult mStatus;
1.82 + bool mNonBlocking;
1.83 +};
1.84 +
1.85 +#endif // nsBaseContentStream_h__
