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/* -*- 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
#include "nsGZFileWriter.h"
#include "nsIFile.h"
#include "nsString.h"
#include "zlib.h"
#ifdef XP_WIN
# include <io.h>
# define _dup dup
#else
# include <unistd.h>
#endif
nsGZFileWriter::nsGZFileWriter(Operation aMode)
: mMode(aMode), mInitialized(false), mFinished(false), mGZFile(nullptr) {}
nsGZFileWriter::~nsGZFileWriter() {
if (mInitialized && !mFinished) {
Finish();
}
}
nsresult nsGZFileWriter::Init(nsIFile* aFile) {
if (NS_WARN_IF(mInitialized) || NS_WARN_IF(mFinished)) {
return NS_ERROR_FAILURE;
}
// Get a FILE out of our nsIFile. Convert that into a file descriptor which
// gzip can own. Then close our FILE, leaving only gzip's fd open.
FILE* file;
nsresult rv = aFile->OpenANSIFileDesc(mMode == Create ? "wb" : "ab", &file);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
return InitANSIFileDesc(file);
}
nsresult nsGZFileWriter::InitANSIFileDesc(FILE* aFile) {
if (NS_WARN_IF(mInitialized) || NS_WARN_IF(mFinished)) {
return NS_ERROR_FAILURE;
}
mGZFile = gzdopen(dup(fileno(aFile)), mMode == Create ? "wb" : "ab");
fclose(aFile);
// gzdopen returns nullptr on error.
if (NS_WARN_IF(!mGZFile)) {
return NS_ERROR_FAILURE;
}
mInitialized = true;
return NS_OK;
}
nsresult nsGZFileWriter::Write(const nsACString& aStr) {
if (NS_WARN_IF(!mInitialized) || NS_WARN_IF(mFinished)) {
return NS_ERROR_FAILURE;
}
// gzwrite uses a return value of 0 to indicate failure. Otherwise, it
// returns the number of uncompressed bytes written. To ensure we can
// distinguish between success and failure, don't call gzwrite when we have 0
// bytes to write.
if (aStr.IsEmpty()) {
return NS_OK;
}
// gzwrite never does a short write -- that is, the return value should
// always be either 0 or aStr.Length(), and we shouldn't have to call it
// multiple times in order to get it to read the whole buffer.
int rv = gzwrite(mGZFile, aStr.BeginReading(), aStr.Length());
if (NS_WARN_IF(rv != static_cast<int>(aStr.Length()))) {
return NS_ERROR_FAILURE;
}
return NS_OK;
}
nsresult nsGZFileWriter::Finish() {
if (NS_WARN_IF(!mInitialized) || NS_WARN_IF(mFinished)) {
return NS_ERROR_FAILURE;
}
mFinished = true;
gzclose(mGZFile);
// Ignore errors from gzclose; it's not like there's anything we can do about
// it, at this point!
return NS_OK;
}