/* -*- 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 nsStreamUtils_h__ #define nsStreamUtils_h__ #include "nsCOMPtr.h" #include "nsStringFwd.h" #include "nsIInputStream.h" #include "nsTArray.h" class nsIOutputStream; class nsIInputStreamCallback; class nsIOutputStreamCallback; class nsIEventTarget; /** * A "one-shot" proxy of the OnInputStreamReady callback. The resulting * proxy object's OnInputStreamReady function may only be called once! The * proxy object ensures that the real notify object will be free'd on the * thread corresponding to the given event target regardless of what thread * the proxy object is destroyed on. * * This function is designed to be used to implement AsyncWait when the * aTarget parameter is non-null. */ extern already_AddRefed<nsIInputStreamCallback> NS_NewInputStreamReadyEvent(nsIInputStreamCallback* aNotify, nsIEventTarget* aTarget); /** * A "one-shot" proxy of the OnOutputStreamReady callback. The resulting * proxy object's OnOutputStreamReady function may only be called once! The * proxy object ensures that the real notify object will be free'd on the * thread corresponding to the given event target regardless of what thread * the proxy object is destroyed on. * * This function is designed to be used to implement AsyncWait when the * aTarget parameter is non-null. */ extern already_AddRefed<nsIOutputStreamCallback> NS_NewOutputStreamReadyEvent(nsIOutputStreamCallback* aNotify, nsIEventTarget* aTarget); /* ------------------------------------------------------------------------- */ enum nsAsyncCopyMode { NS_ASYNCCOPY_VIA_READSEGMENTS, NS_ASYNCCOPY_VIA_WRITESEGMENTS }; /** * This function is called when a new chunk of data has been copied. The * reported count is the size of the current chunk. */ typedef void (* nsAsyncCopyProgressFun)(void* closure, uint32_t count); /** * This function is called when the async copy process completes. The reported * status is NS_OK on success and some error code on failure. */ typedef void (* nsAsyncCopyCallbackFun)(void* closure, nsresult status); /** * This function asynchronously copies data from the source to the sink. All * data transfer occurs on the thread corresponding to the given event target. * A null event target is not permitted. * * The copier handles blocking or non-blocking streams transparently. If a * stream operation returns NS_BASE_STREAM_WOULD_BLOCK, then the stream will * be QI'd to nsIAsync{In,Out}putStream and its AsyncWait method will be used * to determine when to resume copying. * * Source and sink are closed by default when copying finishes or when error * occurs. Caller can prevent closing source or sink by setting aCloseSource * or aCloseSink to false. * * Caller can obtain aCopierCtx to be able to cancel copying. */ extern nsresult NS_AsyncCopy(nsIInputStream* aSource, nsIOutputStream* aSink, nsIEventTarget* aTarget, nsAsyncCopyMode aMode = NS_ASYNCCOPY_VIA_READSEGMENTS, uint32_t aChunkSize = 4096, nsAsyncCopyCallbackFun aCallbackFun = nullptr, void* aCallbackClosure = nullptr, bool aCloseSource = true, bool aCloseSink = true, nsISupports** aCopierCtx = nullptr, nsAsyncCopyProgressFun aProgressCallbackFun = nullptr); /** * This function cancels copying started by function NS_AsyncCopy. * * @param aCopierCtx * Copier context returned by NS_AsyncCopy. * @param aReason * A failure code indicating why the operation is being canceled. * It is an error to pass a success code. */ extern nsresult NS_CancelAsyncCopy(nsISupports* aCopierCtx, nsresult aReason); /** * This function copies all of the available data from the stream (up to at * most aMaxCount bytes) into the given buffer. The buffer is truncated at * the start of the function. * * If an error occurs while reading from the stream or while attempting to * resize the buffer, then the corresponding error code is returned from this * function, and any data that has already been read will be returned in the * output buffer. This allows one to use this function with a non-blocking * input stream that may return NS_BASE_STREAM_WOULD_BLOCK if it only has * partial data available. * * @param aSource * The input stream to read. * @param aMaxCount * The maximum number of bytes to consume from the stream. Pass the * value UINT32_MAX to consume the entire stream. The number of * bytes actually read is given by the length of aBuffer upon return. * @param aBuffer * The string object that will contain the stream data upon return. * Note: The data copied to the string may contain null bytes and may * contain non-ASCII values. */ extern nsresult NS_ConsumeStream(nsIInputStream* aSource, uint32_t aMaxCount, nsACString& aBuffer); /** * This function tests whether or not the input stream is buffered. A buffered * input stream is one that implements readSegments. The test for this is to * 1/ check whether the input stream implements nsIBufferedInputStream; * 2/ if not, call readSegments, without actually consuming any data from the * stream, to verify that it functions. * * NOTE: If the stream is non-blocking and has no data available yet, then this * test will fail. In that case, we return false even though the test is not * really conclusive. * * PERFORMANCE NOTE: If the stream does not implement nsIBufferedInputStream, * calling readSegments may cause I/O. Therefore, you should avoid calling * this function from the main thread. * * @param aInputStream * The input stream to test. */ extern bool NS_InputStreamIsBuffered(nsIInputStream* aInputStream); /** * This function tests whether or not the output stream is buffered. A * buffered output stream is one that implements writeSegments. The test for * this is to: * 1/ check whether the output stream implements nsIBufferedOutputStream; * 2/ if not, call writeSegments, without actually writing any data into * the stream, to verify that it functions. * * NOTE: If the stream is non-blocking and has no available space yet, then * this test will fail. In that case, we return false even though the test is * not really conclusive. * * PERFORMANCE NOTE: If the stream does not implement nsIBufferedOutputStream, * calling writeSegments may cause I/O. Therefore, you should avoid calling * this function from the main thread. * * @param aOutputStream * The output stream to test. */ extern bool NS_OutputStreamIsBuffered(nsIOutputStream* aOutputStream); /** * This function is intended to be passed to nsIInputStream::ReadSegments to * copy data from the nsIInputStream into a nsIOutputStream passed as the * aClosure parameter to the ReadSegments function. * * @see nsIInputStream.idl for a description of this function's parameters. */ extern nsresult NS_CopySegmentToStream(nsIInputStream* aInputStream, void* aClosure, const char* aFromSegment, uint32_t aToOffset, uint32_t aCount, uint32_t* aWriteCount); /** * This function is intended to be passed to nsIInputStream::ReadSegments to * copy data from the nsIInputStream into a character buffer passed as the * aClosure parameter to the ReadSegments function. The character buffer * must be at least as large as the aCount parameter passed to ReadSegments. * * @see nsIInputStream.idl for a description of this function's parameters. */ extern nsresult NS_CopySegmentToBuffer(nsIInputStream* aInputStream, void* aClosure, const char* aFromSegment, uint32_t aToOffset, uint32_t aCount, uint32_t* aWriteCount); /** * This function is intended to be passed to nsIOutputStream::WriteSegments to * copy data into the nsIOutputStream from a character buffer passed as the * aClosure parameter to the WriteSegments function. * * @see nsIOutputStream.idl for a description of this function's parameters. */ extern nsresult NS_CopySegmentToBuffer(nsIOutputStream* aOutputStream, void* aClosure, char* aToSegment, uint32_t aFromOffset, uint32_t aCount, uint32_t* aReadCount); /** * This function is intended to be passed to nsIInputStream::ReadSegments to * discard data from the nsIInputStream. This can be used to efficiently read * data from the stream without actually copying any bytes. * * @see nsIInputStream.idl for a description of this function's parameters. */ extern nsresult NS_DiscardSegment(nsIInputStream* aInputStream, void* aClosure, const char* aFromSegment, uint32_t aToOffset, uint32_t aCount, uint32_t* aWriteCount); /** * This function is intended to be passed to nsIInputStream::ReadSegments to * adjust the aInputStream parameter passed to a consumer's WriteSegmentFun. * The aClosure parameter must be a pointer to a nsWriteSegmentThunk object. * The mStream and mClosure members of that object will be passed to the mFun * function, with the remainder of the parameters being what are passed to * NS_WriteSegmentThunk. * * This function comes in handy when implementing ReadSegments in terms of an * inner stream's ReadSegments. */ extern nsresult NS_WriteSegmentThunk(nsIInputStream* aInputStream, void* aClosure, const char* aFromSegment, uint32_t aToOffset, uint32_t aCount, uint32_t* aWriteCount); struct MOZ_STACK_CLASS nsWriteSegmentThunk { nsCOMPtr<nsIInputStream> mStream; nsWriteSegmentFun mFun; void* mClosure; }; /** * Read data from aInput and store in aDest. A non-zero aKeep will keep that * many bytes from aDest (from the end). New data is appended after the kept * bytes (if any). aDest's new length on returning from this function is * aKeep + aNewBytes and is guaranteed to be less than or equal to aDest's * current capacity. * @param aDest the array to fill * @param aInput the stream to read from * @param aKeep number of bytes to keep (0 <= aKeep <= aDest.Length()) * @param aNewBytes (out) number of bytes read from aInput or zero if Read() * failed * @return the result from aInput->Read(...) */ extern nsresult NS_FillArray(FallibleTArray<char>& aDest, nsIInputStream* aInput, uint32_t aKeep, uint32_t* aNewBytes); /** * Return true if the given stream can be directly cloned. */ extern bool NS_InputStreamIsCloneable(nsIInputStream* aSource); /** * Clone the provided source stream in the most efficient way possible. This * first attempts to QI to nsICloneableInputStream to use Clone(). If that is * not supported or its cloneable attribute is false, then a fallback clone is * provided by copying the source to a pipe. In this case the caller must * replace the source stream with the resulting replacement stream. The clone * and the replacement stream are then cloneable using nsICloneableInputStream * without duplicating memory. This fallback clone using the pipe is only * performed if a replacement stream parameter is also passed in. * @param aSource The input stream to clone. * @param aCloneOut Required out parameter to hold resulting clone. * @param aReplacementOut Optional out parameter to hold stream to replace * original source stream after clone. If not * provided then the fallback clone process is not * supported and a non-cloneable source will result * in failure. Replacement streams are non-blocking. * @return NS_OK on successful clone. Error otherwise. */ extern nsresult NS_CloneInputStream(nsIInputStream* aSource, nsIInputStream** aCloneOut, nsIInputStream** aReplacementOut = nullptr); #endif // !nsStreamUtils_h__