gecko-dev/xpcom/io/nsScriptableInputStream.cpp

117 строки
3.1 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */
#include "nsScriptableInputStream.h"
#include "nsMemory.h"
#include "nsString.h"
NS_IMPL_ISUPPORTS1(nsScriptableInputStream, nsIScriptableInputStream)
// nsIScriptableInputStream methods
NS_IMETHODIMP
nsScriptableInputStream::Close(void) {
if (!mInputStream) return NS_ERROR_NOT_INITIALIZED;
return mInputStream->Close();
}
NS_IMETHODIMP
nsScriptableInputStream::Init(nsIInputStream *aInputStream) {
if (!aInputStream) return NS_ERROR_NULL_POINTER;
mInputStream = aInputStream;
return NS_OK;
}
NS_IMETHODIMP
nsScriptableInputStream::Available(uint64_t *_retval) {
if (!mInputStream) return NS_ERROR_NOT_INITIALIZED;
return mInputStream->Available(_retval);
}
NS_IMETHODIMP
nsScriptableInputStream::Read(uint32_t aCount, char **_retval) {
nsresult rv = NS_OK;
uint64_t count64 = 0;
char *buffer = nullptr;
if (!mInputStream) return NS_ERROR_NOT_INITIALIZED;
rv = mInputStream->Available(&count64);
if (NS_FAILED(rv)) return rv;
// bug716556 - Ensure count+1 doesn't overflow
uint32_t count = XPCOM_MIN((uint32_t)XPCOM_MIN<uint64_t>(count64, aCount), UINT32_MAX - 1);
buffer = (char*)moz_malloc(count+1); // make room for '\0'
if (!buffer) return NS_ERROR_OUT_OF_MEMORY;
rv = ReadHelper(buffer, count);
if (NS_FAILED(rv)) {
nsMemory::Free(buffer);
return rv;
}
buffer[count] = '\0';
*_retval = buffer;
return NS_OK;
}
NS_IMETHODIMP
nsScriptableInputStream::ReadBytes(uint32_t aCount, nsACString &_retval) {
if (!mInputStream) {
return NS_ERROR_NOT_INITIALIZED;
}
_retval.SetLength(aCount);
if (_retval.Length() != aCount) {
return NS_ERROR_OUT_OF_MEMORY;
}
char *ptr = _retval.BeginWriting();
nsresult rv = ReadHelper(ptr, aCount);
if (NS_FAILED(rv)) {
_retval.Truncate();
}
return rv;
}
nsresult
nsScriptableInputStream::ReadHelper(char* aBuffer, uint32_t aCount)
{
uint32_t totalBytesRead = 0;
while (1) {
uint32_t bytesRead;
nsresult rv = mInputStream->Read(aBuffer + totalBytesRead,
aCount - totalBytesRead,
&bytesRead);
if (NS_FAILED(rv)) {
return rv;
}
totalBytesRead += bytesRead;
if (totalBytesRead == aCount) {
break;
}
// If we have read zero bytes, we have hit EOF.
if (bytesRead == 0) {
return NS_ERROR_FAILURE;
}
}
return NS_OK;
}
nsresult
nsScriptableInputStream::Create(nsISupports *aOuter, REFNSIID aIID, void **aResult) {
if (aOuter) return NS_ERROR_NO_AGGREGATION;
nsScriptableInputStream *sis = new nsScriptableInputStream();
if (!sis) return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(sis);
nsresult rv = sis->QueryInterface(aIID, aResult);
NS_RELEASE(sis);
return rv;
}