gecko-dev/netwerk/base/nsTemporaryFileInputStream.cpp

248 строки
6.7 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "nsTemporaryFileInputStream.h"
#include "nsStreamUtils.h"
#include <algorithm>
typedef mozilla::ipc::FileDescriptor::PlatformHandleType FileHandleType;
NS_IMPL_ISUPPORTS(nsTemporaryFileInputStream,
nsIInputStream,
nsISeekableStream,
nsIIPCSerializableInputStream)
nsTemporaryFileInputStream::nsTemporaryFileInputStream(FileDescOwner* aFileDescOwner, uint64_t aStartPos, uint64_t aEndPos)
: mFileDescOwner(aFileDescOwner),
mStartPos(aStartPos),
mCurPos(aStartPos),
mEndPos(aEndPos),
mClosed(false)
{
NS_ASSERTION(aStartPos <= aEndPos, "StartPos should less equal than EndPos!");
}
nsTemporaryFileInputStream::nsTemporaryFileInputStream()
: mStartPos(0),
mCurPos(0),
mEndPos(0),
mClosed(false)
{
}
NS_IMETHODIMP
nsTemporaryFileInputStream::Close()
{
mClosed = true;
return NS_OK;
}
NS_IMETHODIMP
nsTemporaryFileInputStream::Available(uint64_t * bytesAvailable)
{
if (mClosed)
return NS_BASE_STREAM_CLOSED;
NS_ASSERTION(mCurPos <= mEndPos, "CurPos should less equal than EndPos!");
*bytesAvailable = mEndPos - mCurPos;
return NS_OK;
}
NS_IMETHODIMP
nsTemporaryFileInputStream::Read(char* buffer, uint32_t count, uint32_t* bytesRead)
{
return ReadSegments(NS_CopySegmentToBuffer, buffer, count, bytesRead);
}
NS_IMETHODIMP
nsTemporaryFileInputStream::ReadSegments(nsWriteSegmentFun writer,
void * closure,
uint32_t count,
uint32_t * result)
{
NS_ASSERTION(result, "null ptr");
NS_ASSERTION(mCurPos <= mEndPos, "bad stream state");
*result = 0;
if (mClosed) {
return NS_BASE_STREAM_CLOSED;
}
mozilla::MutexAutoLock lock(mFileDescOwner->FileMutex());
int64_t offset = PR_Seek64(mFileDescOwner->mFD, mCurPos, PR_SEEK_SET);
if (offset == -1) {
return NS_ErrorAccordingToNSPR();
}
// Limit requested count to the amount remaining in our section of the file.
count = std::min(count, uint32_t(mEndPos - mCurPos));
char buf[4096];
while (*result < count) {
uint32_t bufCount = std::min(count - *result, (uint32_t) sizeof(buf));
int32_t bytesRead = PR_Read(mFileDescOwner->mFD, buf, bufCount);
if (bytesRead < 0) {
return NS_ErrorAccordingToNSPR();
}
int32_t bytesWritten = 0;
while (bytesWritten < bytesRead) {
uint32_t writerCount = 0;
nsresult rv = writer(this, closure, buf + bytesWritten, *result,
bytesRead - bytesWritten, &writerCount);
if (NS_FAILED(rv) || writerCount == 0) {
// nsIInputStream::ReadSegments' contract specifies that errors
// from writer are not propagated to ReadSegments' caller.
//
// If writer fails, leaving bytes still in buf, that's okay: we
// only update mCurPos to reflect successful writes, so the call
// to PR_Seek64 at the top will restart us at the right spot.
return NS_OK;
}
NS_ASSERTION(writerCount <= (uint32_t) (bytesRead - bytesWritten),
"writer should not write more than we asked it to write");
bytesWritten += writerCount;
*result += writerCount;
mCurPos += writerCount;
}
}
return NS_OK;
}
NS_IMETHODIMP
nsTemporaryFileInputStream::IsNonBlocking(bool * nonBlocking)
{
*nonBlocking = false;
return NS_OK;
}
NS_IMETHODIMP
nsTemporaryFileInputStream::Seek(int32_t aWhence, int64_t aOffset)
{
if (mClosed) {
return NS_BASE_STREAM_CLOSED;
}
switch (aWhence) {
case nsISeekableStream::NS_SEEK_SET:
aOffset += mStartPos;
break;
case nsISeekableStream::NS_SEEK_CUR:
aOffset += mCurPos;
break;
case nsISeekableStream::NS_SEEK_END:
aOffset += mEndPos;
break;
default:
return NS_ERROR_FAILURE;
}
if (aOffset < (int64_t)mStartPos || aOffset > (int64_t)mEndPos) {
return NS_ERROR_INVALID_ARG;
}
mCurPos = aOffset;
return NS_OK;
}
NS_IMETHODIMP
nsTemporaryFileInputStream::Tell(int64_t* aPos)
{
if (!aPos) {
return NS_ERROR_FAILURE;
}
if (mClosed) {
return NS_BASE_STREAM_CLOSED;
}
MOZ_ASSERT(mStartPos <= mCurPos, "StartPos should less equal than CurPos!");
*aPos = mCurPos - mStartPos;
return NS_OK;
}
NS_IMETHODIMP
nsTemporaryFileInputStream::SetEOF()
{
if (mClosed) {
return NS_BASE_STREAM_CLOSED;
}
return Close();
}
void
nsTemporaryFileInputStream::Serialize(InputStreamParams& aParams,
FileDescriptorArray& aFileDescriptors)
{
TemporaryFileInputStreamParams params;
MutexAutoLock lock(mFileDescOwner->FileMutex());
MOZ_ASSERT(mFileDescOwner->mFD);
if (!mClosed) {
FileHandleType fd = FileHandleType(PR_FileDesc2NativeHandle(mFileDescOwner->mFD));
NS_ASSERTION(fd, "This should never be null!");
DebugOnly<FileDescriptor*> dbgFD = aFileDescriptors.AppendElement(fd);
NS_ASSERTION(dbgFD->IsValid(), "Sending an invalid file descriptor!");
params.fileDescriptorIndex() = aFileDescriptors.Length() - 1;
Close();
} else {
NS_WARNING("The stream is already closed. "
"Sending an invalid file descriptor to the other process!");
params.fileDescriptorIndex() = UINT32_MAX;
}
params.startPos() = mCurPos;
params.endPos() = mEndPos;
aParams = params;
}
bool
nsTemporaryFileInputStream::Deserialize(const InputStreamParams& aParams,
const FileDescriptorArray& aFileDescriptors)
{
const TemporaryFileInputStreamParams& params = aParams.get_TemporaryFileInputStreamParams();
uint32_t fileDescriptorIndex = params.fileDescriptorIndex();
FileDescriptor fd;
if (fileDescriptorIndex < aFileDescriptors.Length()) {
fd = aFileDescriptors[fileDescriptorIndex];
NS_WARNING_ASSERTION(fd.IsValid(),
"Received an invalid file descriptor!");
} else {
NS_WARNING("Received a bad file descriptor index!");
}
if (fd.IsValid()) {
auto rawFD = fd.ClonePlatformHandle();
PRFileDesc* fileDesc = PR_ImportFile(PROsfd(rawFD.release()));
if (!fileDesc) {
NS_WARNING("Failed to import file handle!");
return false;
}
mFileDescOwner = new FileDescOwner(fileDesc);
} else {
mClosed = true;
}
mStartPos = mCurPos = params.startPos();
mEndPos = params.endPos();
return true;
}
Maybe<uint64_t>
nsTemporaryFileInputStream::ExpectedSerializedLength()
{
return Nothing();
}