Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 840 insertions, 0 deletions

diff --git a/netwerk/cache2/CacheFileChunk.cpp b/netwerk/cache2/CacheFileChunk.cpp
new file mode 100644
index 0000000000..7dc0d9078c
--- /dev/null
+++ b/netwerk/cache2/CacheFileChunk.cpp
@@ -0,0 +1,840 @@
+/* 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 "CacheLog.h"
+#include "CacheFileChunk.h"
+
+#include "CacheFile.h"
+#include "nsThreadUtils.h"
+
+#include "mozilla/IntegerPrintfMacros.h"
+
+namespace mozilla::net {
+
+#define kMinBufSize 512
+
+CacheFileChunkBuffer::CacheFileChunkBuffer(CacheFileChunk* aChunk)
+    : mChunk(aChunk),
+      mBuf(nullptr),
+      mBufSize(0),
+      mDataSize(0),
+      mReadHandlesCount(0),
+      mWriteHandleExists(false) {}
+
+CacheFileChunkBuffer::~CacheFileChunkBuffer() {
+  if (mBuf) {
+    CacheFileUtils::FreeBuffer(mBuf);
+    mBuf = nullptr;
+    mChunk->BuffersAllocationChanged(mBufSize, 0);
+    mBufSize = 0;
+  }
+}
+
+void CacheFileChunkBuffer::CopyFrom(CacheFileChunkBuffer* aOther) {
+  MOZ_RELEASE_ASSERT(mBufSize >= aOther->mDataSize);
+  mDataSize = aOther->mDataSize;
+  memcpy(mBuf, aOther->mBuf, mDataSize);
+}
+
+nsresult CacheFileChunkBuffer::FillInvalidRanges(
+    CacheFileChunkBuffer* aOther, CacheFileUtils::ValidityMap* aMap) {
+  nsresult rv;
+
+  rv = EnsureBufSize(aOther->mDataSize);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  uint32_t invalidOffset = 0;
+  uint32_t invalidLength;
+
+  for (uint32_t i = 0; i < aMap->Length(); ++i) {
+    uint32_t validOffset = (*aMap)[i].Offset();
+    uint32_t validLength = (*aMap)[i].Len();
+
+    MOZ_RELEASE_ASSERT(invalidOffset <= validOffset);
+    invalidLength = validOffset - invalidOffset;
+    if (invalidLength > 0) {
+      MOZ_RELEASE_ASSERT(invalidOffset + invalidLength <= aOther->mDataSize);
+      memcpy(mBuf + invalidOffset, aOther->mBuf + invalidOffset, invalidLength);
+    }
+    invalidOffset = validOffset + validLength;
+  }
+
+  if (invalidOffset < aOther->mDataSize) {
+    invalidLength = aOther->mDataSize - invalidOffset;
+    memcpy(mBuf + invalidOffset, aOther->mBuf + invalidOffset, invalidLength);
+  }
+
+  return NS_OK;
+}
+
+[[nodiscard]] nsresult CacheFileChunkBuffer::EnsureBufSize(uint32_t aBufSize) {
+  AssertOwnsLock();
+
+  if (mBufSize >= aBufSize) {
+    return NS_OK;
+  }
+
+  // find smallest power of 2 greater than or equal to aBufSize
+  aBufSize--;
+  aBufSize |= aBufSize >> 1;
+  aBufSize |= aBufSize >> 2;
+  aBufSize |= aBufSize >> 4;
+  aBufSize |= aBufSize >> 8;
+  aBufSize |= aBufSize >> 16;
+  aBufSize++;
+
+  const uint32_t minBufSize = kMinBufSize;
+  const uint32_t maxBufSize = kChunkSize;
+  aBufSize = clamped(aBufSize, minBufSize, maxBufSize);
+
+  if (!mChunk->CanAllocate(aBufSize - mBufSize)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  char* newBuf = static_cast<char*>(realloc(mBuf, aBufSize));
+  if (!newBuf) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  mChunk->BuffersAllocationChanged(mBufSize, aBufSize);
+  mBuf = newBuf;
+  mBufSize = aBufSize;
+
+  return NS_OK;
+}
+
+void CacheFileChunkBuffer::SetDataSize(uint32_t aDataSize) {
+  MOZ_RELEASE_ASSERT(
+      // EnsureBufSize must be called before SetDataSize, so the new data size
+      // is guaranteed to be smaller than or equal to mBufSize.
+      aDataSize <= mBufSize ||
+      // The only exception is an optimization when we read the data from the
+      // disk. The data is read to a separate buffer and CacheFileChunk::mBuf is
+      // empty (see CacheFileChunk::Read). We need to set mBuf::mDataSize
+      // accordingly so that DataSize() methods return correct value, but we
+      // don't want to allocate the buffer since it wouldn't be used in most
+      // cases.
+      (mBufSize == 0 && mChunk->mState == CacheFileChunk::READING));
+
+  mDataSize = aDataSize;
+}
+
+void CacheFileChunkBuffer::AssertOwnsLock() const { mChunk->AssertOwnsLock(); }
+
+void CacheFileChunkBuffer::RemoveReadHandle() {
+  AssertOwnsLock();
+  MOZ_RELEASE_ASSERT(mReadHandlesCount);
+  MOZ_RELEASE_ASSERT(!mWriteHandleExists);
+  mReadHandlesCount--;
+
+  if (mReadHandlesCount == 0 && mChunk->mBuf != this) {
+    DebugOnly<bool> removed = mChunk->mOldBufs.RemoveElement(this);
+    MOZ_ASSERT(removed);
+  }
+}
+
+void CacheFileChunkBuffer::RemoveWriteHandle() {
+  AssertOwnsLock();
+  MOZ_RELEASE_ASSERT(mReadHandlesCount == 0);
+  MOZ_RELEASE_ASSERT(mWriteHandleExists);
+  mWriteHandleExists = false;
+}
+
+size_t CacheFileChunkBuffer::SizeOfIncludingThis(
+    mozilla::MallocSizeOf mallocSizeOf) const {
+  size_t n = mallocSizeOf(this);
+
+  if (mBuf) {
+    n += mallocSizeOf(mBuf);
+  }
+
+  return n;
+}
+
+uint32_t CacheFileChunkHandle::DataSize() {
+  MOZ_ASSERT(mBuf, "Unexpected call on dummy handle");
+  mBuf->AssertOwnsLock();
+  return mBuf->mDataSize;
+}
+
+uint32_t CacheFileChunkHandle::Offset() {
+  MOZ_ASSERT(mBuf, "Unexpected call on dummy handle");
+  mBuf->AssertOwnsLock();
+  return mBuf->mChunk->Index() * kChunkSize;
+}
+
+CacheFileChunkReadHandle::CacheFileChunkReadHandle(CacheFileChunkBuffer* aBuf) {
+  mBuf = aBuf;
+  mBuf->mReadHandlesCount++;
+}
+
+CacheFileChunkReadHandle::~CacheFileChunkReadHandle() {
+  mBuf->RemoveReadHandle();
+}
+
+const char* CacheFileChunkReadHandle::Buf() { return mBuf->mBuf; }
+
+CacheFileChunkWriteHandle::CacheFileChunkWriteHandle(
+    CacheFileChunkBuffer* aBuf) {
+  mBuf = aBuf;
+  if (mBuf) {
+    MOZ_ASSERT(!mBuf->mWriteHandleExists);
+    mBuf->mWriteHandleExists = true;
+  }
+}
+
+CacheFileChunkWriteHandle::~CacheFileChunkWriteHandle() {
+  if (mBuf) {
+    mBuf->RemoveWriteHandle();
+  }
+}
+
+char* CacheFileChunkWriteHandle::Buf() { return mBuf ? mBuf->mBuf : nullptr; }
+
+void CacheFileChunkWriteHandle::UpdateDataSize(uint32_t aOffset,
+                                               uint32_t aLen) {
+  MOZ_ASSERT(mBuf, "Write performed on dummy handle?");
+  MOZ_ASSERT(aOffset <= mBuf->mDataSize);
+  MOZ_ASSERT(aOffset + aLen <= mBuf->mBufSize);
+
+  if (aOffset + aLen > mBuf->mDataSize) {
+    mBuf->mDataSize = aOffset + aLen;
+  }
+
+  mBuf->mChunk->UpdateDataSize(aOffset, aLen);
+}
+
+class NotifyUpdateListenerEvent : public Runnable {
+ public:
+  NotifyUpdateListenerEvent(CacheFileChunkListener* aCallback,
+                            CacheFileChunk* aChunk)
+      : Runnable("net::NotifyUpdateListenerEvent"),
+        mCallback(aCallback),
+        mChunk(aChunk) {
+    LOG(("NotifyUpdateListenerEvent::NotifyUpdateListenerEvent() [this=%p]",
+         this));
+  }
+
+ protected:
+  ~NotifyUpdateListenerEvent() {
+    LOG(("NotifyUpdateListenerEvent::~NotifyUpdateListenerEvent() [this=%p]",
+         this));
+  }
+
+ public:
+  NS_IMETHOD Run() override {
+    LOG(("NotifyUpdateListenerEvent::Run() [this=%p]", this));
+
+    mCallback->OnChunkUpdated(mChunk);
+    return NS_OK;
+  }
+
+ protected:
+  nsCOMPtr<CacheFileChunkListener> mCallback;
+  RefPtr<CacheFileChunk> mChunk;
+};
+
+bool CacheFileChunk::DispatchRelease() {
+  if (NS_IsMainThread()) {
+    return false;
+  }
+
+  NS_DispatchToMainThread(NewNonOwningRunnableMethod(
+      "net::CacheFileChunk::Release", this, &CacheFileChunk::Release));
+
+  return true;
+}
+
+NS_IMPL_ADDREF(CacheFileChunk)
+NS_IMETHODIMP_(MozExternalRefCountType)
+CacheFileChunk::Release() {
+  nsrefcnt count = mRefCnt - 1;
+  if (DispatchRelease()) {
+    // Redispatched to the main thread.
+    return count;
+  }
+
+  MOZ_ASSERT(0 != mRefCnt, "dup release");
+  count = --mRefCnt;
+  NS_LOG_RELEASE(this, count, "CacheFileChunk");
+
+  if (0 == count) {
+    mRefCnt = 1;
+    delete (this);
+    return 0;
+  }
+
+  // We can safely access this chunk after decreasing mRefCnt since we re-post
+  // all calls to Release() happening off the main thread to the main thread.
+  // I.e. no other Release() that would delete the object could be run before
+  // we call CacheFile::DeactivateChunk().
+  //
+  // NOTE: we don't grab the CacheFile's lock, so the chunk might be addrefed
+  // on another thread before CacheFile::DeactivateChunk() grabs the lock on
+  // this thread. To make sure we won't deactivate chunk that was just returned
+  // to a new consumer we check mRefCnt once again in
+  // CacheFile::DeactivateChunk() after we grab the lock.
+  if (mActiveChunk && count == 1) {
+    mFile->DeactivateChunk(this);
+  }
+
+  return count;
+}
+
+NS_INTERFACE_MAP_BEGIN(CacheFileChunk)
+  NS_INTERFACE_MAP_ENTRY(mozilla::net::CacheFileIOListener)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+CacheFileChunk::CacheFileChunk(CacheFile* aFile, uint32_t aIndex,
+                               bool aInitByWriter)
+    : CacheMemoryConsumer(aFile->mOpenAsMemoryOnly ? MEMORY_ONLY : DONT_REPORT),
+      mIndex(aIndex),
+      mState(INITIAL),
+      mStatus(NS_OK),
+      mActiveChunk(false),
+      mIsDirty(false),
+      mDiscardedChunk(false),
+      mBuffersSize(0),
+      mLimitAllocation(!aFile->mOpenAsMemoryOnly && aInitByWriter),
+      mIsPriority(aFile->mPriority),
+      mExpectedHash(0),
+      mFile(aFile) {
+  LOG(("CacheFileChunk::CacheFileChunk() [this=%p, index=%u, initByWriter=%d]",
+       this, aIndex, aInitByWriter));
+  mBuf = new CacheFileChunkBuffer(this);
+}
+
+CacheFileChunk::~CacheFileChunk() {
+  LOG(("CacheFileChunk::~CacheFileChunk() [this=%p]", this));
+}
+
+void CacheFileChunk::AssertOwnsLock() const { mFile->AssertOwnsLock(); }
+
+void CacheFileChunk::InitNew() {
+  AssertOwnsLock();
+
+  LOG(("CacheFileChunk::InitNew() [this=%p]", this));
+
+  MOZ_ASSERT(mState == INITIAL);
+  MOZ_ASSERT(NS_SUCCEEDED(mStatus));
+  MOZ_ASSERT(!mBuf->Buf());
+  MOZ_ASSERT(!mWritingStateHandle);
+  MOZ_ASSERT(!mReadingStateBuf);
+  MOZ_ASSERT(!mIsDirty);
+
+  mBuf = new CacheFileChunkBuffer(this);
+  mState = READY;
+}
+
+nsresult CacheFileChunk::Read(CacheFileHandle* aHandle, uint32_t aLen,
+                              CacheHash::Hash16_t aHash,
+                              CacheFileChunkListener* aCallback) {
+  AssertOwnsLock();
+
+  LOG(("CacheFileChunk::Read() [this=%p, handle=%p, len=%d, listener=%p]", this,
+       aHandle, aLen, aCallback));
+
+  MOZ_ASSERT(mState == INITIAL);
+  MOZ_ASSERT(NS_SUCCEEDED(mStatus));
+  MOZ_ASSERT(!mBuf->Buf());
+  MOZ_ASSERT(!mWritingStateHandle);
+  MOZ_ASSERT(!mReadingStateBuf);
+  MOZ_ASSERT(aLen);
+
+  nsresult rv;
+
+  mState = READING;
+
+  RefPtr<CacheFileChunkBuffer> tmpBuf = new CacheFileChunkBuffer(this);
+  rv = tmpBuf->EnsureBufSize(aLen);
+  if (NS_FAILED(rv)) {
+    SetError(rv);
+    return mStatus;
+  }
+  tmpBuf->SetDataSize(aLen);
+
+  rv = CacheFileIOManager::Read(aHandle, mIndex * kChunkSize, tmpBuf->Buf(),
+                                aLen, this);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    rv = mIndex ? NS_ERROR_FILE_CORRUPTED : NS_ERROR_FILE_NOT_FOUND;
+    SetError(rv);
+  } else {
+    mReadingStateBuf.swap(tmpBuf);
+    mListener = aCallback;
+    // mBuf contains no data but we set datasize to size of the data that will
+    // be read from the disk. No handle is allowed to access the non-existent
+    // data until reading finishes, but data can be appended or overwritten.
+    // These pieces are tracked in mValidityMap and will be merged with the data
+    // read from disk in OnDataRead().
+    mBuf->SetDataSize(aLen);
+    mExpectedHash = aHash;
+  }
+
+  return rv;
+}
+
+nsresult CacheFileChunk::Write(CacheFileHandle* aHandle,
+                               CacheFileChunkListener* aCallback) {
+  AssertOwnsLock();
+
+  LOG(("CacheFileChunk::Write() [this=%p, handle=%p, listener=%p]", this,
+       aHandle, aCallback));
+
+  MOZ_ASSERT(mState == READY);
+  MOZ_ASSERT(NS_SUCCEEDED(mStatus));
+  MOZ_ASSERT(!mWritingStateHandle);
+  MOZ_ASSERT(mBuf->DataSize());  // Don't write chunk when it is empty
+  MOZ_ASSERT(mBuf->ReadHandlesCount() == 0);
+  MOZ_ASSERT(!mBuf->WriteHandleExists());
+
+  nsresult rv;
+
+  mState = WRITING;
+  mWritingStateHandle = MakeUnique<CacheFileChunkReadHandle>(mBuf);
+
+  rv = CacheFileIOManager::Write(
+      aHandle, mIndex * kChunkSize, mWritingStateHandle->Buf(),
+      mWritingStateHandle->DataSize(), false, false, this);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    mWritingStateHandle = nullptr;
+    SetError(rv);
+  } else {
+    mListener = aCallback;
+    mIsDirty = false;
+  }
+
+  return rv;
+}
+
+void CacheFileChunk::WaitForUpdate(CacheFileChunkListener* aCallback) {
+  AssertOwnsLock();
+  mFile->AssertOwnsLock();  // For thread-safety analysis
+
+  LOG(("CacheFileChunk::WaitForUpdate() [this=%p, listener=%p]", this,
+       aCallback));
+
+  MOZ_ASSERT(mFile->mOutput);
+  MOZ_ASSERT(IsReady());
+
+#ifdef DEBUG
+  for (uint32_t i = 0; i < mUpdateListeners.Length(); i++) {
+    MOZ_ASSERT(mUpdateListeners[i]->mCallback != aCallback);
+  }
+#endif
+
+  ChunkListenerItem* item = new ChunkListenerItem();
+  item->mTarget = CacheFileIOManager::IOTarget();
+  if (!item->mTarget) {
+    LOG(
+        ("CacheFileChunk::WaitForUpdate() - Cannot get Cache I/O thread! Using "
+         "main thread for callback."));
+    item->mTarget = GetMainThreadSerialEventTarget();
+  }
+  item->mCallback = aCallback;
+  MOZ_ASSERT(item->mTarget);
+  item->mCallback = aCallback;
+
+  mUpdateListeners.AppendElement(item);
+}
+
+void CacheFileChunk::CancelWait(CacheFileChunkListener* aCallback) {
+  AssertOwnsLock();
+
+  LOG(("CacheFileChunk::CancelWait() [this=%p, listener=%p]", this, aCallback));
+
+  MOZ_ASSERT(IsReady());
+
+  uint32_t i;
+  for (i = 0; i < mUpdateListeners.Length(); i++) {
+    ChunkListenerItem* item = mUpdateListeners[i];
+
+    if (item->mCallback == aCallback) {
+      mUpdateListeners.RemoveElementAt(i);
+      delete item;
+      break;
+    }
+  }
+
+#ifdef DEBUG
+  for (; i < mUpdateListeners.Length(); i++) {
+    MOZ_ASSERT(mUpdateListeners[i]->mCallback != aCallback);
+  }
+#endif
+}
+
+nsresult CacheFileChunk::NotifyUpdateListeners() {
+  AssertOwnsLock();
+
+  LOG(("CacheFileChunk::NotifyUpdateListeners() [this=%p]", this));
+
+  MOZ_ASSERT(IsReady());
+
+  nsresult rv, rv2;
+
+  rv = NS_OK;
+  for (uint32_t i = 0; i < mUpdateListeners.Length(); i++) {
+    ChunkListenerItem* item = mUpdateListeners[i];
+
+    LOG(
+        ("CacheFileChunk::NotifyUpdateListeners() - Notifying listener %p "
+         "[this=%p]",
+         item->mCallback.get(), this));
+
+    RefPtr<NotifyUpdateListenerEvent> ev;
+    ev = new NotifyUpdateListenerEvent(item->mCallback, this);
+    rv2 = item->mTarget->Dispatch(ev, NS_DISPATCH_NORMAL);
+    if (NS_FAILED(rv2) && NS_SUCCEEDED(rv)) rv = rv2;
+    delete item;
+  }
+
+  mUpdateListeners.Clear();
+
+  return rv;
+}
+
+uint32_t CacheFileChunk::Index() const { return mIndex; }
+
+CacheHash::Hash16_t CacheFileChunk::Hash() const {
+  MOZ_ASSERT(IsReady());
+
+  return CacheHash::Hash16(mBuf->Buf(), mBuf->DataSize());
+}
+
+uint32_t CacheFileChunk::DataSize() const { return mBuf->DataSize(); }
+
+void CacheFileChunk::UpdateDataSize(uint32_t aOffset, uint32_t aLen) {
+  AssertOwnsLock();
+  mFile->AssertOwnsLock();  // For thread-safety analysis
+
+  // UpdateDataSize() is called only when we've written some data to the chunk
+  // and we never write data anymore once some error occurs.
+  MOZ_ASSERT(NS_SUCCEEDED(mStatus));
+
+  LOG(("CacheFileChunk::UpdateDataSize() [this=%p, offset=%d, len=%d]", this,
+       aOffset, aLen));
+
+  mIsDirty = true;
+
+  int64_t fileSize = static_cast<int64_t>(kChunkSize) * mIndex + aOffset + aLen;
+  bool notify = false;
+
+  if (fileSize > mFile->mDataSize) {
+    mFile->mDataSize = fileSize;
+    notify = true;
+  }
+
+  if (mState == READY || mState == WRITING) {
+    MOZ_ASSERT(mValidityMap.Length() == 0);
+
+    if (notify) {
+      NotifyUpdateListeners();
+    }
+
+    return;
+  }
+
+  // We're still waiting for data from the disk. This chunk cannot be used by
+  // input stream, so there must be no update listener. We also need to keep
+  // track of where the data is written so that we can correctly merge the new
+  // data with the old one.
+
+  MOZ_ASSERT(mUpdateListeners.Length() == 0);
+  MOZ_ASSERT(mState == READING);
+
+  mValidityMap.AddPair(aOffset, aLen);
+  mValidityMap.Log();
+}
+
+void CacheFileChunk::Truncate(uint32_t aOffset) {
+  MOZ_RELEASE_ASSERT(mState == READY || mState == WRITING || mState == READING);
+
+  if (mState == READING) {
+    mIsDirty = true;
+  }
+
+  mBuf->SetDataSize(aOffset);
+}
+
+nsresult CacheFileChunk::OnFileOpened(CacheFileHandle* aHandle,
+                                      nsresult aResult) {
+  MOZ_CRASH("CacheFileChunk::OnFileOpened should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult CacheFileChunk::OnDataWritten(CacheFileHandle* aHandle,
+                                       const char* aBuf, nsresult aResult) {
+  LOG((
+      "CacheFileChunk::OnDataWritten() [this=%p, handle=%p, result=0x%08" PRIx32
+      "]",
+      this, aHandle, static_cast<uint32_t>(aResult)));
+
+  nsCOMPtr<CacheFileChunkListener> listener;
+
+  {
+    CacheFileAutoLock lock(mFile);
+
+    MOZ_ASSERT(mState == WRITING);
+    MOZ_ASSERT(mListener);
+
+    mWritingStateHandle = nullptr;
+
+    if (NS_WARN_IF(NS_FAILED(aResult))) {
+      SetError(aResult);
+    }
+
+    mState = READY;
+    mListener.swap(listener);
+  }
+
+  listener->OnChunkWritten(aResult, this);
+
+  return NS_OK;
+}
+
+nsresult CacheFileChunk::OnDataRead(CacheFileHandle* aHandle, char* aBuf,
+                                    nsresult aResult) {
+  LOG(("CacheFileChunk::OnDataRead() [this=%p, handle=%p, result=0x%08" PRIx32
+       "]",
+       this, aHandle, static_cast<uint32_t>(aResult)));
+
+  nsCOMPtr<CacheFileChunkListener> listener;
+
+  {
+    CacheFileAutoLock lock(mFile);
+
+    MOZ_ASSERT(mState == READING);
+    MOZ_ASSERT(mListener);
+    MOZ_ASSERT(mReadingStateBuf);
+    MOZ_RELEASE_ASSERT(mBuf->ReadHandlesCount() == 0);
+    MOZ_RELEASE_ASSERT(!mBuf->WriteHandleExists());
+
+    RefPtr<CacheFileChunkBuffer> tmpBuf;
+    tmpBuf.swap(mReadingStateBuf);
+
+    if (NS_SUCCEEDED(aResult)) {
+      CacheHash::Hash16_t hash =
+          CacheHash::Hash16(tmpBuf->Buf(), tmpBuf->DataSize());
+      if (hash != mExpectedHash) {
+        LOG(
+            ("CacheFileChunk::OnDataRead() - Hash mismatch! Hash of the data is"
+             " %hx, hash in metadata is %hx. [this=%p, idx=%d]",
+             hash, mExpectedHash, this, mIndex));
+        aResult = NS_ERROR_FILE_CORRUPTED;
+      } else {
+        if (mBuf->DataSize() < tmpBuf->DataSize()) {
+          // Truncate() was called while the data was being read.
+          tmpBuf->SetDataSize(mBuf->DataSize());
+        }
+
+        if (!mBuf->Buf()) {
+          // Just swap the buffers if mBuf is still empty
+          mBuf.swap(tmpBuf);
+        } else {
+          LOG(("CacheFileChunk::OnDataRead() - Merging buffers. [this=%p]",
+               this));
+
+          mValidityMap.Log();
+          aResult = mBuf->FillInvalidRanges(tmpBuf, &mValidityMap);
+          mValidityMap.Clear();
+        }
+      }
+    }
+
+    if (NS_FAILED(aResult)) {
+      aResult = mIndex ? NS_ERROR_FILE_CORRUPTED : NS_ERROR_FILE_NOT_FOUND;
+      SetError(aResult);
+      mBuf->SetDataSize(0);
+    }
+
+    mState = READY;
+    mListener.swap(listener);
+  }
+
+  listener->OnChunkRead(aResult, this);
+
+  return NS_OK;
+}
+
+nsresult CacheFileChunk::OnFileDoomed(CacheFileHandle* aHandle,
+                                      nsresult aResult) {
+  MOZ_CRASH("CacheFileChunk::OnFileDoomed should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult CacheFileChunk::OnEOFSet(CacheFileHandle* aHandle, nsresult aResult) {
+  MOZ_CRASH("CacheFileChunk::OnEOFSet should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult CacheFileChunk::OnFileRenamed(CacheFileHandle* aHandle,
+                                       nsresult aResult) {
+  MOZ_CRASH("CacheFileChunk::OnFileRenamed should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+bool CacheFileChunk::IsKilled() { return mFile->IsKilled(); }
+
+bool CacheFileChunk::IsReady() const {
+  return (NS_SUCCEEDED(mStatus) && (mState == READY || mState == WRITING));
+}
+
+bool CacheFileChunk::IsDirty() const {
+  AssertOwnsLock();
+
+  return mIsDirty;
+}
+
+nsresult CacheFileChunk::GetStatus() { return mStatus; }
+
+void CacheFileChunk::SetError(nsresult aStatus) {
+  LOG(("CacheFileChunk::SetError() [this=%p, status=0x%08" PRIx32 "]", this,
+       static_cast<uint32_t>(aStatus)));
+
+  MOZ_ASSERT(NS_FAILED(aStatus));
+
+  if (NS_FAILED(mStatus)) {
+    // Remember only the first error code.
+    return;
+  }
+
+  mStatus = aStatus;
+}
+
+CacheFileChunkReadHandle CacheFileChunk::GetReadHandle() {
+  LOG(("CacheFileChunk::GetReadHandle() [this=%p]", this));
+
+  AssertOwnsLock();
+
+  MOZ_RELEASE_ASSERT(mState == READY || mState == WRITING);
+  // We don't release the lock when writing the data and CacheFileOutputStream
+  // doesn't get the read handle, so there cannot be a write handle when read
+  // handle is obtained.
+  MOZ_RELEASE_ASSERT(!mBuf->WriteHandleExists());
+
+  return CacheFileChunkReadHandle(mBuf);
+}
+
+CacheFileChunkWriteHandle CacheFileChunk::GetWriteHandle(
+    uint32_t aEnsuredBufSize) {
+  LOG(("CacheFileChunk::GetWriteHandle() [this=%p, ensuredBufSize=%u]", this,
+       aEnsuredBufSize));
+
+  AssertOwnsLock();
+
+  if (NS_FAILED(mStatus)) {
+    return CacheFileChunkWriteHandle(nullptr);  // dummy handle
+  }
+
+  nsresult rv;
+
+  // We don't support multiple write handles
+  MOZ_RELEASE_ASSERT(!mBuf->WriteHandleExists());
+
+  if (mBuf->ReadHandlesCount()) {
+    LOG(
+        ("CacheFileChunk::GetWriteHandle() - cloning buffer because of existing"
+         " read handle"));
+
+    MOZ_RELEASE_ASSERT(mState != READING);
+    RefPtr<CacheFileChunkBuffer> newBuf = new CacheFileChunkBuffer(this);
+    rv = newBuf->EnsureBufSize(std::max(aEnsuredBufSize, mBuf->DataSize()));
+    if (NS_SUCCEEDED(rv)) {
+      newBuf->CopyFrom(mBuf);
+      mOldBufs.AppendElement(mBuf);
+      mBuf = newBuf;
+    }
+  } else {
+    rv = mBuf->EnsureBufSize(aEnsuredBufSize);
+  }
+
+  if (NS_FAILED(rv)) {
+    SetError(NS_ERROR_OUT_OF_MEMORY);
+    return CacheFileChunkWriteHandle(nullptr);  // dummy handle
+  }
+
+  return CacheFileChunkWriteHandle(mBuf);
+}
+
+// Memory reporting
+
+size_t CacheFileChunk::SizeOfExcludingThis(
+    mozilla::MallocSizeOf mallocSizeOf) const {
+  size_t n = mBuf->SizeOfIncludingThis(mallocSizeOf);
+
+  if (mReadingStateBuf) {
+    n += mReadingStateBuf->SizeOfIncludingThis(mallocSizeOf);
+  }
+
+  for (uint32_t i = 0; i < mOldBufs.Length(); ++i) {
+    n += mOldBufs[i]->SizeOfIncludingThis(mallocSizeOf);
+  }
+
+  n += mValidityMap.SizeOfExcludingThis(mallocSizeOf);
+
+  return n;
+}
+
+size_t CacheFileChunk::SizeOfIncludingThis(
+    mozilla::MallocSizeOf mallocSizeOf) const {
+  return mallocSizeOf(this) + SizeOfExcludingThis(mallocSizeOf);
+}
+
+bool CacheFileChunk::CanAllocate(uint32_t aSize) const {
+  if (!mLimitAllocation) {
+    return true;
+  }
+
+  LOG(("CacheFileChunk::CanAllocate() [this=%p, size=%u]", this, aSize));
+
+  int64_t limit = CacheObserver::MaxDiskChunksMemoryUsage(mIsPriority);
+  if (limit == 0) {
+    return true;
+  }
+
+  limit <<= 10;
+  if (limit > UINT32_MAX) {
+    limit = UINT32_MAX;
+  }
+
+  int64_t usage = ChunksMemoryUsage();
+  if (usage + aSize > limit) {
+    LOG(("CacheFileChunk::CanAllocate() - Returning false. [this=%p]", this));
+    return false;
+  }
+
+  return true;
+}
+
+void CacheFileChunk::BuffersAllocationChanged(uint32_t aFreed,
+                                              uint32_t aAllocated) {
+  uint32_t oldBuffersSize = mBuffersSize;
+  mBuffersSize += aAllocated;
+  mBuffersSize -= aFreed;
+
+  DoMemoryReport(sizeof(CacheFileChunk) + mBuffersSize);
+
+  if (!mLimitAllocation) {
+    return;
+  }
+
+  ChunksMemoryUsage() -= oldBuffersSize;
+  ChunksMemoryUsage() += mBuffersSize;
+  LOG(
+      ("CacheFileChunk::BuffersAllocationChanged() - %s chunks usage %u "
+       "[this=%p]",
+       mIsPriority ? "Priority" : "Normal",
+       static_cast<uint32_t>(ChunksMemoryUsage()), this));
+}
+
+mozilla::Atomic<uint32_t, ReleaseAcquire>& CacheFileChunk::ChunksMemoryUsage()
+    const {
+  static mozilla::Atomic<uint32_t, ReleaseAcquire> chunksMemoryUsage(0);
+  static mozilla::Atomic<uint32_t, ReleaseAcquire> prioChunksMemoryUsage(0);
+  return mIsPriority ? prioChunksMemoryUsage : chunksMemoryUsage;
+}
+
+}  // namespace mozilla::net