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-rw-r--r--xpcom/io/SlicedInputStream.h102
1 files changed, 102 insertions, 0 deletions
diff --git a/xpcom/io/SlicedInputStream.h b/xpcom/io/SlicedInputStream.h
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+++ b/xpcom/io/SlicedInputStream.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 SlicedInputStream_h
+#define SlicedInputStream_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Mutex.h"
+#include "nsCOMPtr.h"
+#include "nsIAsyncInputStream.h"
+#include "nsICloneableInputStream.h"
+#include "nsIIPCSerializableInputStream.h"
+#include "nsISeekableStream.h"
+#include "nsIInputStreamLength.h"
+
+namespace mozilla {
+
+// A wrapper for a slice of an underlying input stream.
+
+class SlicedInputStream final : public nsIAsyncInputStream,
+ public nsICloneableInputStream,
+ public nsIIPCSerializableInputStream,
+ public nsISeekableStream,
+ public nsIInputStreamCallback,
+ public nsIInputStreamLength,
+ public nsIAsyncInputStreamLength,
+ public nsIInputStreamLengthCallback {
+ public:
+ NS_DECL_THREADSAFE_ISUPPORTS
+ NS_DECL_NSIINPUTSTREAM
+ NS_DECL_NSIASYNCINPUTSTREAM
+ NS_DECL_NSICLONEABLEINPUTSTREAM
+ NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
+ NS_DECL_NSISEEKABLESTREAM
+ NS_DECL_NSITELLABLESTREAM
+ NS_DECL_NSIINPUTSTREAMCALLBACK
+ NS_DECL_NSIINPUTSTREAMLENGTH
+ NS_DECL_NSIASYNCINPUTSTREAMLENGTH
+ NS_DECL_NSIINPUTSTREAMLENGTHCALLBACK
+
+ // Create an input stream whose data comes from a slice of aInputStream. The
+ // slice begins at aStart bytes beyond aInputStream's current position, and
+ // extends for a maximum of aLength bytes. If aInputStream contains fewer
+ // than aStart bytes, reading from SlicedInputStream returns no data. If
+ // aInputStream contains more than aStart bytes, but fewer than aStart +
+ // aLength bytes, reading from SlicedInputStream returns as many bytes as can
+ // be consumed from aInputStream after reading aLength bytes.
+ //
+ // aInputStream should not be read from after constructing a
+ // SlicedInputStream wrapper around it.
+
+ SlicedInputStream(already_AddRefed<nsIInputStream> aInputStream,
+ uint64_t aStart, uint64_t aLength);
+
+ // This CTOR is meant to be used just for IPC.
+ SlicedInputStream();
+
+ private:
+ ~SlicedInputStream();
+
+ void SetSourceStream(already_AddRefed<nsIInputStream> aInputStream);
+
+ uint64_t AdjustRange(uint64_t aRange);
+
+ nsCOMPtr<nsIInputStream> mInputStream;
+
+ // Raw pointers because these are just QI of mInputStream.
+ nsICloneableInputStream* mWeakCloneableInputStream;
+ nsIIPCSerializableInputStream* mWeakIPCSerializableInputStream;
+ nsISeekableStream* mWeakSeekableInputStream;
+ nsITellableStream* mWeakTellableInputStream;
+ nsIAsyncInputStream* mWeakAsyncInputStream;
+ nsIInputStreamLength* mWeakInputStreamLength;
+ nsIAsyncInputStreamLength* mWeakAsyncInputStreamLength;
+
+ uint64_t mStart;
+ uint64_t mLength;
+ uint64_t mCurPos;
+
+ bool mClosed;
+
+ // These four are used for AsyncWait. They are protected by mutex because
+ // touched on multiple threads.
+ nsCOMPtr<nsIInputStreamCallback> mAsyncWaitCallback MOZ_GUARDED_BY(mMutex);
+ nsCOMPtr<nsIEventTarget> mAsyncWaitEventTarget MOZ_GUARDED_BY(mMutex);
+ uint32_t mAsyncWaitFlags MOZ_GUARDED_BY(mMutex);
+ uint32_t mAsyncWaitRequestedCount MOZ_GUARDED_BY(mMutex);
+
+ // This is use for nsIAsyncInputStreamLength::AsyncWait.
+ // This is protected by mutex.
+ nsCOMPtr<nsIInputStreamLengthCallback> mAsyncWaitLengthCallback
+ MOZ_GUARDED_BY(mMutex);
+
+ Mutex mMutex;
+};
+
+} // namespace mozilla
+
+#endif // SlicedInputStream_h