gecko-dev/xpcom/io/nsScriptableInputStream.cpp

124 строки
3.0 KiB
C++

/* -*- 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/. */
#include "nsScriptableInputStream.h"
#include "nsMemory.h"
#include "nsString.h"
NS_IMPL_ISUPPORTS(nsScriptableInputStream, nsIScriptableInputStream)
// nsIScriptableInputStream methods
NS_IMETHODIMP
nsScriptableInputStream::Close() {
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* aResult) {
if (!mInputStream) {
return NS_ERROR_NOT_INITIALIZED;
}
return mInputStream->Available(aResult);
}
NS_IMETHODIMP
nsScriptableInputStream::Read(uint32_t aCount, char** aResult) {
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*)malloc(count + 1); // make room for '\0'
if (!buffer) {
return NS_ERROR_OUT_OF_MEMORY;
}
rv = ReadHelper(buffer, count);
if (NS_FAILED(rv)) {
free(buffer);
return rv;
}
buffer[count] = '\0';
*aResult = buffer;
return NS_OK;
}
NS_IMETHODIMP
nsScriptableInputStream::ReadBytes(uint32_t aCount, nsACString& aResult) {
if (!mInputStream) {
return NS_ERROR_NOT_INITIALIZED;
}
if (!aResult.SetLength(aCount, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
MOZ_ASSERT(aResult.Length() == aCount);
char* ptr = aResult.BeginWriting();
nsresult rv = ReadHelper(ptr, aCount);
if (NS_FAILED(rv)) {
aResult.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;
}
RefPtr<nsScriptableInputStream> sis = new nsScriptableInputStream();
return sis->QueryInterface(aIID, aResult);
}