mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-29 21:25:35 +00:00
363 lines
11 KiB
C++
363 lines
11 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 "mozilla/SnappyUncompressInputStream.h"
|
|
|
|
#include <algorithm>
|
|
#include "nsIAsyncInputStream.h"
|
|
#include "nsStreamUtils.h"
|
|
#include "snappy/snappy.h"
|
|
|
|
namespace mozilla {
|
|
|
|
NS_IMPL_ISUPPORTS(SnappyUncompressInputStream,
|
|
nsIInputStream);
|
|
|
|
// Putting kCompressedBufferLength inside a function avoids a static
|
|
// constructor.
|
|
static size_t CompressedBufferLength()
|
|
{
|
|
static size_t kCompressedBufferLength =
|
|
detail::SnappyFrameUtils::MaxCompressedBufferLength(snappy::kBlockSize);
|
|
|
|
MOZ_ASSERT(kCompressedBufferLength > 0);
|
|
return kCompressedBufferLength;
|
|
}
|
|
|
|
SnappyUncompressInputStream::SnappyUncompressInputStream(nsIInputStream* aBaseStream)
|
|
: mBaseStream(aBaseStream)
|
|
, mUncompressedBytes(0)
|
|
, mNextByte(0)
|
|
, mNextChunkType(Unknown)
|
|
, mNextChunkDataLength(0)
|
|
, mNeedFirstStreamIdentifier(true)
|
|
{
|
|
// This implementation only supports sync base streams. Verify this in debug
|
|
// builds. Note, this is a bit complicated because the streams we support
|
|
// advertise different capabilities:
|
|
// - nsFileInputStream - blocking and sync
|
|
// - nsStringInputStream - non-blocking and sync
|
|
// - nsPipeInputStream - can be blocking, but provides async interface
|
|
#ifdef DEBUG
|
|
bool baseNonBlocking;
|
|
nsresult rv = mBaseStream->IsNonBlocking(&baseNonBlocking);
|
|
MOZ_ASSERT(NS_SUCCEEDED(rv));
|
|
if (baseNonBlocking) {
|
|
nsCOMPtr<nsIAsyncInputStream> async = do_QueryInterface(mBaseStream);
|
|
MOZ_ASSERT(!async);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
SnappyUncompressInputStream::Close()
|
|
{
|
|
if (!mBaseStream) {
|
|
return NS_OK;
|
|
}
|
|
|
|
mBaseStream->Close();
|
|
mBaseStream = nullptr;
|
|
|
|
mUncompressedBuffer = nullptr;
|
|
mCompressedBuffer = nullptr;
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
SnappyUncompressInputStream::Available(uint64_t* aLengthOut)
|
|
{
|
|
if (!mBaseStream) {
|
|
return NS_BASE_STREAM_CLOSED;
|
|
}
|
|
|
|
// If we have uncompressed bytes, then we are done.
|
|
*aLengthOut = UncompressedLength();
|
|
if (*aLengthOut > 0) {
|
|
return NS_OK;
|
|
}
|
|
|
|
// Otherwise, attempt to uncompress bytes until we get something or the
|
|
// underlying stream is drained. We loop here because some chunks can
|
|
// be StreamIdentifiers, padding, etc with no data.
|
|
uint32_t bytesRead;
|
|
do {
|
|
nsresult rv = ParseNextChunk(&bytesRead);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
*aLengthOut = UncompressedLength();
|
|
} while(*aLengthOut == 0 && bytesRead);
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
SnappyUncompressInputStream::Read(char* aBuf, uint32_t aCount,
|
|
uint32_t* aBytesReadOut)
|
|
{
|
|
return ReadSegments(NS_CopySegmentToBuffer, aBuf, aCount, aBytesReadOut);
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
SnappyUncompressInputStream::ReadSegments(nsWriteSegmentFun aWriter,
|
|
void* aClosure, uint32_t aCount,
|
|
uint32_t* aBytesReadOut)
|
|
{
|
|
*aBytesReadOut = 0;
|
|
|
|
if (!mBaseStream) {
|
|
return NS_BASE_STREAM_CLOSED;
|
|
}
|
|
|
|
nsresult rv;
|
|
|
|
// Do not try to use the base stream's ReadSegements here. Its very
|
|
// unlikely we will get a single buffer that contains all of the compressed
|
|
// data and therefore would have to copy into our own buffer anyways.
|
|
// Instead, focus on making efficient use of the Read() interface.
|
|
|
|
while (aCount > 0) {
|
|
// We have some decompressed data in our buffer. Provide it to the
|
|
// callers writer function.
|
|
if (mUncompressedBytes > 0) {
|
|
MOZ_ASSERT(mUncompressedBuffer);
|
|
uint32_t remaining = UncompressedLength();
|
|
uint32_t numToWrite = std::min(aCount, remaining);
|
|
uint32_t numWritten;
|
|
rv = aWriter(this, aClosure, &mUncompressedBuffer[mNextByte], *aBytesReadOut,
|
|
numToWrite, &numWritten);
|
|
|
|
// As defined in nsIInputputStream.idl, do not pass writer func errors.
|
|
if (NS_FAILED(rv)) {
|
|
return NS_OK;
|
|
}
|
|
|
|
// End-of-file
|
|
if (numWritten == 0) {
|
|
return NS_OK;
|
|
}
|
|
|
|
*aBytesReadOut += numWritten;
|
|
mNextByte += numWritten;
|
|
MOZ_ASSERT(mNextByte <= mUncompressedBytes);
|
|
|
|
if (mNextByte == mUncompressedBytes) {
|
|
mNextByte = 0;
|
|
mUncompressedBytes = 0;
|
|
}
|
|
|
|
aCount -= numWritten;
|
|
|
|
continue;
|
|
}
|
|
|
|
// Otherwise uncompress the next chunk and loop. Any resulting data
|
|
// will set mUncompressedBytes which we check at the top of the loop.
|
|
uint32_t bytesRead;
|
|
rv = ParseNextChunk(&bytesRead);
|
|
if (NS_FAILED(rv)) { return rv; }
|
|
|
|
// If we couldn't read anything and there is no more data to provide
|
|
// to the caller, then this is eof.
|
|
if (bytesRead == 0 && mUncompressedBytes == 0) {
|
|
return NS_OK;
|
|
}
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
NS_IMETHODIMP
|
|
SnappyUncompressInputStream::IsNonBlocking(bool* aNonBlockingOut)
|
|
{
|
|
*aNonBlockingOut = false;
|
|
return NS_OK;
|
|
}
|
|
|
|
SnappyUncompressInputStream::~SnappyUncompressInputStream()
|
|
{
|
|
Close();
|
|
}
|
|
|
|
nsresult
|
|
SnappyUncompressInputStream::ParseNextChunk(uint32_t* aBytesReadOut)
|
|
{
|
|
// There must not be any uncompressed data already in mUncompressedBuffer.
|
|
MOZ_ASSERT(mUncompressedBytes == 0);
|
|
MOZ_ASSERT(mNextByte == 0);
|
|
|
|
nsresult rv;
|
|
*aBytesReadOut = 0;
|
|
|
|
// Lazily create our two buffers so we can report OOM during stream
|
|
// operation. These allocations only happens once. The buffers are reused
|
|
// until the stream is closed.
|
|
if (!mUncompressedBuffer) {
|
|
mUncompressedBuffer.reset(new (fallible) char[snappy::kBlockSize]);
|
|
if (NS_WARN_IF(!mUncompressedBuffer)) {
|
|
return NS_ERROR_OUT_OF_MEMORY;
|
|
}
|
|
}
|
|
|
|
if (!mCompressedBuffer) {
|
|
mCompressedBuffer.reset(new (fallible) char[CompressedBufferLength()]);
|
|
if (NS_WARN_IF(!mCompressedBuffer)) {
|
|
return NS_ERROR_OUT_OF_MEMORY;
|
|
}
|
|
}
|
|
|
|
// We have no decompressed data and we also have not seen the start of stream
|
|
// yet. Read and validate the StreamIdentifier chunk. Also read the next
|
|
// header to determine the size of the first real data chunk.
|
|
if (mNeedFirstStreamIdentifier) {
|
|
const uint32_t firstReadLength = kHeaderLength +
|
|
kStreamIdentifierDataLength +
|
|
kHeaderLength;
|
|
MOZ_ASSERT(firstReadLength <= CompressedBufferLength());
|
|
|
|
rv = ReadAll(mCompressedBuffer.get(), firstReadLength, firstReadLength,
|
|
aBytesReadOut);
|
|
if (NS_WARN_IF(NS_FAILED(rv)) || *aBytesReadOut == 0) { return rv; }
|
|
|
|
rv = ParseHeader(mCompressedBuffer.get(), kHeaderLength,
|
|
&mNextChunkType, &mNextChunkDataLength);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
if (NS_WARN_IF(mNextChunkType != StreamIdentifier ||
|
|
mNextChunkDataLength != kStreamIdentifierDataLength)) {
|
|
return NS_ERROR_CORRUPTED_CONTENT;
|
|
}
|
|
size_t offset = kHeaderLength;
|
|
|
|
mNeedFirstStreamIdentifier = false;
|
|
|
|
size_t numRead;
|
|
size_t numWritten;
|
|
rv = ParseData(mUncompressedBuffer.get(), snappy::kBlockSize, mNextChunkType,
|
|
&mCompressedBuffer[offset],
|
|
mNextChunkDataLength, &numWritten, &numRead);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
MOZ_ASSERT(numWritten == 0);
|
|
MOZ_ASSERT(numRead == mNextChunkDataLength);
|
|
offset += numRead;
|
|
|
|
rv = ParseHeader(&mCompressedBuffer[offset], *aBytesReadOut - offset,
|
|
&mNextChunkType, &mNextChunkDataLength);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
// We have no compressed data and we don't know how big the next chunk is.
|
|
// This happens when we get an EOF pause in the middle of a stream and also
|
|
// at the end of the stream. Simply read the next header and return. The
|
|
// chunk body will be read on the next entry into this method.
|
|
if (mNextChunkType == Unknown) {
|
|
rv = ReadAll(mCompressedBuffer.get(), kHeaderLength, kHeaderLength,
|
|
aBytesReadOut);
|
|
if (NS_WARN_IF(NS_FAILED(rv)) || *aBytesReadOut == 0) { return rv; }
|
|
|
|
rv = ParseHeader(mCompressedBuffer.get(), kHeaderLength,
|
|
&mNextChunkType, &mNextChunkDataLength);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
// We have no decompressed data, but we do know the size of the next chunk.
|
|
// Read at least that much from the base stream.
|
|
uint32_t readLength = mNextChunkDataLength;
|
|
MOZ_ASSERT(readLength <= CompressedBufferLength());
|
|
|
|
// However, if there is enough data in the base stream, also read the next
|
|
// chunk header. This helps optimize the stream by avoiding many small reads.
|
|
uint64_t avail;
|
|
rv = mBaseStream->Available(&avail);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
if (avail >= (readLength + kHeaderLength)) {
|
|
readLength += kHeaderLength;
|
|
MOZ_ASSERT(readLength <= CompressedBufferLength());
|
|
}
|
|
|
|
rv = ReadAll(mCompressedBuffer.get(), readLength, mNextChunkDataLength,
|
|
aBytesReadOut);
|
|
if (NS_WARN_IF(NS_FAILED(rv)) || *aBytesReadOut == 0) { return rv; }
|
|
|
|
size_t numRead;
|
|
size_t numWritten;
|
|
rv = ParseData(mUncompressedBuffer.get(), snappy::kBlockSize, mNextChunkType,
|
|
mCompressedBuffer.get(), mNextChunkDataLength,
|
|
&numWritten, &numRead);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
MOZ_ASSERT(numRead == mNextChunkDataLength);
|
|
|
|
mUncompressedBytes = numWritten;
|
|
|
|
// If we were unable to directly read the next chunk header, then clear
|
|
// our internal state. We will have to perform a small read to get the
|
|
// header the next time we enter this method.
|
|
if (*aBytesReadOut <= mNextChunkDataLength) {
|
|
mNextChunkType = Unknown;
|
|
mNextChunkDataLength = 0;
|
|
return NS_OK;
|
|
}
|
|
|
|
// We got the next chunk header. Parse it so that we are ready to for the
|
|
// next call into this method.
|
|
rv = ParseHeader(&mCompressedBuffer[numRead], *aBytesReadOut - numRead,
|
|
&mNextChunkType, &mNextChunkDataLength);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult
|
|
SnappyUncompressInputStream::ReadAll(char* aBuf, uint32_t aCount,
|
|
uint32_t aMinValidCount,
|
|
uint32_t* aBytesReadOut)
|
|
{
|
|
MOZ_ASSERT(aCount >= aMinValidCount);
|
|
|
|
*aBytesReadOut = 0;
|
|
|
|
if (!mBaseStream) {
|
|
return NS_BASE_STREAM_CLOSED;
|
|
}
|
|
|
|
uint32_t offset = 0;
|
|
while (aCount > 0) {
|
|
uint32_t bytesRead = 0;
|
|
nsresult rv = mBaseStream->Read(aBuf + offset, aCount, &bytesRead);
|
|
if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
|
|
|
|
// EOF, but don't immediately return. We need to validate min read bytes
|
|
// below.
|
|
if (bytesRead == 0) {
|
|
break;
|
|
}
|
|
|
|
*aBytesReadOut += bytesRead;
|
|
offset += bytesRead;
|
|
aCount -= bytesRead;
|
|
}
|
|
|
|
// Reading zero bytes is not an error. Its the expected EOF condition.
|
|
// Only compare to the minimum valid count if we read at least one byte.
|
|
if (*aBytesReadOut != 0 && *aBytesReadOut < aMinValidCount) {
|
|
return NS_ERROR_CORRUPTED_CONTENT;
|
|
}
|
|
|
|
return NS_OK;
|
|
}
|
|
|
|
size_t
|
|
SnappyUncompressInputStream::UncompressedLength() const
|
|
{
|
|
MOZ_ASSERT(mNextByte <= mUncompressedBytes);
|
|
return mUncompressedBytes - mNextByte;
|
|
}
|
|
|
|
} // namespace mozilla
|