зеркало из https://github.com/mozilla/gecko-dev.git
106 строки
3.3 KiB
C++
106 строки
3.3 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsTemporaryFileInputStream.h"
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#include "nsStreamUtils.h"
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#include <algorithm>
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NS_IMPL_ISUPPORTS(nsTemporaryFileInputStream, nsIInputStream)
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nsTemporaryFileInputStream::nsTemporaryFileInputStream(FileDescOwner* aFileDescOwner, uint64_t aStartPos, uint64_t aEndPos)
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: mFileDescOwner(aFileDescOwner),
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mStartPos(aStartPos),
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mEndPos(aEndPos),
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mClosed(false)
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{
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NS_ASSERTION(aStartPos <= aEndPos, "StartPos should less equal than EndPos!");
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}
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NS_IMETHODIMP
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nsTemporaryFileInputStream::Close()
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{
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mClosed = true;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsTemporaryFileInputStream::Available(uint64_t * bytesAvailable)
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{
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if (mClosed)
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return NS_BASE_STREAM_CLOSED;
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NS_ASSERTION(mStartPos <= mEndPos, "StartPos should less equal than EndPos!");
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*bytesAvailable = mEndPos - mStartPos;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsTemporaryFileInputStream::Read(char* buffer, uint32_t count, uint32_t* bytesRead)
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{
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return ReadSegments(NS_CopySegmentToBuffer, buffer, count, bytesRead);
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}
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NS_IMETHODIMP
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nsTemporaryFileInputStream::ReadSegments(nsWriteSegmentFun writer,
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void * closure,
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uint32_t count,
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uint32_t * result)
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{
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NS_ASSERTION(result, "null ptr");
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NS_ASSERTION(mStartPos <= mEndPos, "bad stream state");
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*result = 0;
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if (mClosed) {
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return NS_BASE_STREAM_CLOSED;
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}
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mozilla::MutexAutoLock lock(mFileDescOwner->FileMutex());
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PR_Seek64(mFileDescOwner->mFD, mStartPos, PR_SEEK_SET);
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// Limit requested count to the amount remaining in our section of the file.
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count = std::min(count, uint32_t(mEndPos - mStartPos));
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char buf[4096];
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while (*result < count) {
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uint32_t bufCount = std::min(count - *result, (uint32_t) sizeof(buf));
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int32_t bytesRead = PR_Read(mFileDescOwner->mFD, buf, bufCount);
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if (bytesRead < 0) {
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return NS_ErrorAccordingToNSPR();
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}
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int32_t bytesWritten = 0;
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while (bytesWritten < bytesRead) {
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uint32_t writerCount = 0;
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nsresult rv = writer(this, closure, buf + bytesWritten, *result,
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bytesRead - bytesWritten, &writerCount);
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if (NS_FAILED(rv) || writerCount == 0) {
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// nsIInputStream::ReadSegments' contract specifies that errors
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// from writer are not propagated to ReadSegments' caller.
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//
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// If writer fails, leaving bytes still in buf, that's okay: we
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// only update mStartPos to reflect successful writes, so the call
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// to PR_Seek64 at the top will restart us at the right spot.
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return NS_OK;
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}
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NS_ASSERTION(writerCount <= (uint32_t) (bytesRead - bytesWritten),
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"writer should not write more than we asked it to write");
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bytesWritten += writerCount;
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*result += writerCount;
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mStartPos += writerCount;
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}
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}
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return NS_OK;
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}
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NS_IMETHODIMP
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nsTemporaryFileInputStream::IsNonBlocking(bool * nonBlocking)
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{
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*nonBlocking = false;
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return NS_OK;
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}
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