зеркало из https://github.com/mozilla/gecko-dev.git
134 строки
3.7 KiB
C++
134 строки
3.7 KiB
C++
/* -*- Mode: C++; tab-width: 4; 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 <algorithm>
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#include "ArrayBufferInputStream.h"
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#include "nsStreamUtils.h"
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#include "jsapi.h"
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#include "jsfriendapi.h"
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NS_IMPL_ISUPPORTS(ArrayBufferInputStream, nsIArrayBufferInputStream, nsIInputStream);
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ArrayBufferInputStream::ArrayBufferInputStream()
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: mBufferLength(0)
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, mOffset(0)
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, mPos(0)
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, mClosed(false)
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{
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}
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NS_IMETHODIMP
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ArrayBufferInputStream::SetData(JS::Handle<JS::Value> aBuffer,
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uint32_t aByteOffset,
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uint32_t aLength,
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JSContext* aCx)
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{
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if (!aBuffer.isObject()) {
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return NS_ERROR_FAILURE;
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}
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JS::RootedObject arrayBuffer(aCx, &aBuffer.toObject());
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if (!JS_IsArrayBufferObject(arrayBuffer)) {
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return NS_ERROR_FAILURE;
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}
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mArrayBuffer.emplace(aCx, arrayBuffer);
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uint32_t buflen = JS_GetArrayBufferByteLength(arrayBuffer);
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mOffset = std::min(buflen, aByteOffset);
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mBufferLength = std::min(buflen - mOffset, aLength);
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return NS_OK;
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}
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NS_IMETHODIMP
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ArrayBufferInputStream::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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ArrayBufferInputStream::Available(uint64_t* aCount)
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{
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if (mClosed) {
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return NS_BASE_STREAM_CLOSED;
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}
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if (mArrayBuffer) {
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uint32_t buflen = JS_GetArrayBufferByteLength(mArrayBuffer->get());
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*aCount = buflen ? buflen - mPos : 0;
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} else {
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*aCount = 0;
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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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ArrayBufferInputStream::Read(char* aBuf, uint32_t aCount, uint32_t *aReadCount)
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{
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return ReadSegments(NS_CopySegmentToBuffer, aBuf, aCount, aReadCount);
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}
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NS_IMETHODIMP
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ArrayBufferInputStream::ReadSegments(nsWriteSegmentFun writer, void *closure,
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uint32_t aCount, uint32_t *result)
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{
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NS_ASSERTION(result, "null ptr");
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NS_ASSERTION(mBufferLength >= mPos, "bad stream state");
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if (mClosed) {
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return NS_BASE_STREAM_CLOSED;
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}
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MOZ_ASSERT(mArrayBuffer || (mPos == mBufferLength), "stream inited incorrectly");
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*result = 0;
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while (mPos < mBufferLength) {
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uint32_t remaining = mBufferLength - mPos;
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MOZ_ASSERT(mArrayBuffer);
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uint32_t byteLength = JS_GetArrayBufferByteLength(mArrayBuffer->get());
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if (byteLength == 0) {
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mClosed = true;
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return NS_BASE_STREAM_CLOSED;
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}
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char buffer[8192];
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uint32_t count = std::min(std::min(aCount, remaining), uint32_t(mozilla::ArrayLength(buffer)));
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if (count == 0) {
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break;
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}
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// It is just barely possible that writer() will detach the ArrayBuffer's
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// data, setting its length to zero. Or move the data to a different memory
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// area. (This would only happen in a subclass that passed something other
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// than NS_CopySegmentToBuffer as 'writer'). So copy the data out into a
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// holding area before passing it to writer().
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{
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JS::AutoCheckCannotGC nogc;
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char* src = (char*) JS_GetArrayBufferData(mArrayBuffer->get(), nogc) + mOffset + mPos;
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memcpy(buffer, src, count);
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}
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uint32_t written;
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nsresult rv = writer(this, closure, buffer, 0, count, &written);
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if (NS_FAILED(rv)) {
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// InputStreams do not propagate errors to caller.
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return NS_OK;
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}
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NS_ASSERTION(written <= count,
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"writer should not write more than we asked it to write");
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mPos += written;
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*result += written;
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aCount -= written;
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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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ArrayBufferInputStream::IsNonBlocking(bool *aNonBlocking)
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{
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*aNonBlocking = true;
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return NS_OK;
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}
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