Adding upstream version 110.0.1.upstream/110.0.1upstream

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

1 files changed, 1042 insertions, 0 deletions

diff --git a/netwerk/cache2/CacheFileMetadata.cpp b/netwerk/cache2/CacheFileMetadata.cpp
new file mode 100644
index 0000000000..4299b30a25
--- /dev/null
+++ b/netwerk/cache2/CacheFileMetadata.cpp
@@ -0,0 +1,1042 @@
+/* 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 "CacheFileMetadata.h"
+
+#include "CacheFileIOManager.h"
+#include "nsICacheEntry.h"
+#include "CacheHashUtils.h"
+#include "CacheFileChunk.h"
+#include "CacheFileUtils.h"
+#include "nsILoadContextInfo.h"
+#include "nsICacheEntry.h"  // for nsICacheEntryMetaDataVisitor
+#include "../cache/nsCacheUtils.h"
+#include "nsIFile.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "prnetdb.h"
+
+namespace mozilla::net {
+
+#define kMinMetadataRead 1024  // TODO find optimal value from telemetry
+#define kAlignSize 4096
+
+// Most of the cache entries fit into one chunk due to current chunk size. Make
+// sure to tweak this value if kChunkSize is going to change.
+#define kInitialHashArraySize 1
+
+// Initial elements buffer size.
+#define kInitialBufSize 64
+
+// Max size of elements in bytes.
+#define kMaxElementsSize (64 * 1024)
+
+#define NOW_SECONDS() (uint32_t(PR_Now() / PR_USEC_PER_SEC))
+
+NS_IMPL_ISUPPORTS(CacheFileMetadata, CacheFileIOListener)
+
+CacheFileMetadata::CacheFileMetadata(
+    CacheFileHandle* aHandle, const nsACString& aKey,
+    NotNull<CacheFileUtils::CacheFileLock*> aLock)
+    : CacheMemoryConsumer(NORMAL),
+      mHandle(aHandle),
+      mOffset(-1),
+      mIsDirty(false),
+      mAnonymous(false),
+      mAllocExactSize(false),
+      mFirstRead(true),
+      mLock(aLock) {
+  LOG(("CacheFileMetadata::CacheFileMetadata() [this=%p, handle=%p, key=%s]",
+       this, aHandle, PromiseFlatCString(aKey).get()));
+
+  memset(&mMetaHdr, 0, sizeof(CacheFileMetadataHeader));
+  mMetaHdr.mVersion = kCacheEntryVersion;
+  mMetaHdr.mExpirationTime = nsICacheEntry::NO_EXPIRATION_TIME;
+  mKey = aKey;
+
+  DebugOnly<nsresult> rv{};
+  rv = ParseKey(aKey);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+}
+
+CacheFileMetadata::CacheFileMetadata(
+    bool aMemoryOnly, bool aPinned, const nsACString& aKey,
+    NotNull<CacheFileUtils::CacheFileLock*> aLock)
+    : CacheMemoryConsumer(aMemoryOnly ? MEMORY_ONLY : NORMAL),
+      mIsDirty(true),
+      mAnonymous(false),
+      mAllocExactSize(false),
+      mFirstRead(true),
+      mLock(aLock) {
+  LOG(("CacheFileMetadata::CacheFileMetadata() [this=%p, key=%s]", this,
+       PromiseFlatCString(aKey).get()));
+
+  memset(&mMetaHdr, 0, sizeof(CacheFileMetadataHeader));
+  mMetaHdr.mVersion = kCacheEntryVersion;
+  if (aPinned) {
+    AddFlags(kCacheEntryIsPinned);
+  }
+  mMetaHdr.mExpirationTime = nsICacheEntry::NO_EXPIRATION_TIME;
+  mKey = aKey;
+  mMetaHdr.mKeySize = mKey.Length();
+
+  DebugOnly<nsresult> rv{};
+  rv = ParseKey(aKey);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+}
+
+CacheFileMetadata::CacheFileMetadata()
+    : CacheMemoryConsumer(DONT_REPORT /* This is a helper class */),
+      mIsDirty(false),
+      mAnonymous(false),
+      mAllocExactSize(false),
+      mFirstRead(true),
+      mLock(new CacheFileUtils::CacheFileLock()) {
+  LOG(("CacheFileMetadata::CacheFileMetadata() [this=%p]", this));
+
+  memset(&mMetaHdr, 0, sizeof(CacheFileMetadataHeader));
+}
+
+CacheFileMetadata::~CacheFileMetadata() {
+  LOG(("CacheFileMetadata::~CacheFileMetadata() [this=%p]", this));
+
+  MOZ_ASSERT(!mListener);
+
+  if (mHashArray) {
+    CacheFileUtils::FreeBuffer(mHashArray);
+    mHashArray = nullptr;
+    mHashArraySize = 0;
+  }
+
+  if (mBuf) {
+    CacheFileUtils::FreeBuffer(mBuf);
+    mBuf = nullptr;
+    mBufSize = 0;
+  }
+}
+
+void CacheFileMetadata::SetHandle(CacheFileHandle* aHandle) {
+  LOG(("CacheFileMetadata::SetHandle() [this=%p, handle=%p]", this, aHandle));
+
+  MOZ_ASSERT(!mHandle);
+
+  mHandle = aHandle;
+}
+
+void CacheFileMetadata::ReadMetadata(CacheFileMetadataListener* aListener) {
+  LOG(("CacheFileMetadata::ReadMetadata() [this=%p, listener=%p]", this,
+       aListener));
+
+  MOZ_ASSERT(!mListener);
+  MOZ_ASSERT(!mHashArray);
+  MOZ_ASSERT(!mBuf);
+  MOZ_ASSERT(!mWriteBuf);
+
+  nsresult rv;
+
+  int64_t size = mHandle->FileSize();
+  MOZ_ASSERT(size != -1);
+
+  if (size == 0) {
+    // this is a new entry
+    LOG(
+        ("CacheFileMetadata::ReadMetadata() - Filesize == 0, creating empty "
+         "metadata. [this=%p]",
+         this));
+
+    InitEmptyMetadata();
+    aListener->OnMetadataRead(NS_OK);
+    return;
+  }
+
+  if (size < int64_t(sizeof(CacheFileMetadataHeader) + 2 * sizeof(uint32_t))) {
+    // there must be at least checksum, header and offset
+    LOG(
+        ("CacheFileMetadata::ReadMetadata() - File is corrupted, creating "
+         "empty metadata. [this=%p, filesize=%" PRId64 "]",
+         this, size));
+
+    InitEmptyMetadata();
+    aListener->OnMetadataRead(NS_OK);
+    return;
+  }
+
+  // Set offset so that we read at least kMinMetadataRead if the file is big
+  // enough.
+  int64_t offset;
+  if (size < kMinMetadataRead) {
+    offset = 0;
+  } else {
+    offset = size - kMinMetadataRead;
+  }
+
+  // round offset to kAlignSize blocks
+  offset = (offset / kAlignSize) * kAlignSize;
+
+  mBufSize = size - offset;
+  mBuf = static_cast<char*>(moz_xmalloc(mBufSize));
+
+  DoMemoryReport(MemoryUsage());
+
+  LOG(
+      ("CacheFileMetadata::ReadMetadata() - Reading metadata from disk, trying "
+       "offset=%" PRId64 ", filesize=%" PRId64 " [this=%p]",
+       offset, size, this));
+
+  mReadStart = mozilla::TimeStamp::Now();
+  mListener = aListener;
+  rv = CacheFileIOManager::Read(mHandle, offset, mBuf, mBufSize, this);
+  if (NS_FAILED(rv)) {
+    LOG(
+        ("CacheFileMetadata::ReadMetadata() - CacheFileIOManager::Read() failed"
+         " synchronously, creating empty metadata. [this=%p, rv=0x%08" PRIx32
+         "]",
+         this, static_cast<uint32_t>(rv)));
+
+    mListener = nullptr;
+    InitEmptyMetadata();
+    aListener->OnMetadataRead(NS_OK);
+  }
+}
+
+uint32_t CacheFileMetadata::CalcMetadataSize(uint32_t aElementsSize,
+                                             uint32_t aHashCount) {
+  return sizeof(uint32_t) +                          // hash of the metadata
+         aHashCount * sizeof(CacheHash::Hash16_t) +  // array of chunk hashes
+         sizeof(CacheFileMetadataHeader) +           // metadata header
+         mKey.Length() + 1 +                         // key with trailing null
+         aElementsSize +                             // elements
+         sizeof(uint32_t);                           // offset
+}
+
+nsresult CacheFileMetadata::WriteMetadata(
+    uint32_t aOffset, CacheFileMetadataListener* aListener) {
+  LOG(("CacheFileMetadata::WriteMetadata() [this=%p, offset=%d, listener=%p]",
+       this, aOffset, aListener));
+
+  MOZ_ASSERT(!mListener);
+  MOZ_ASSERT(!mWriteBuf);
+
+  nsresult rv;
+
+  mIsDirty = false;
+
+  mWriteBuf =
+      static_cast<char*>(malloc(CalcMetadataSize(mElementsSize, mHashCount)));
+  if (!mWriteBuf) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  char* p = mWriteBuf + sizeof(uint32_t);
+  if (mHashCount) {
+    memcpy(p, mHashArray, mHashCount * sizeof(CacheHash::Hash16_t));
+    p += mHashCount * sizeof(CacheHash::Hash16_t);
+  }
+  mMetaHdr.WriteToBuf(p);
+  p += sizeof(CacheFileMetadataHeader);
+  memcpy(p, mKey.get(), mKey.Length());
+  p += mKey.Length();
+  *p = 0;
+  p++;
+  if (mElementsSize) {
+    memcpy(p, mBuf, mElementsSize);
+    p += mElementsSize;
+  }
+
+  CacheHash::Hash32_t hash;
+  hash = CacheHash::Hash(mWriteBuf + sizeof(uint32_t),
+                         p - mWriteBuf - sizeof(uint32_t));
+  NetworkEndian::writeUint32(mWriteBuf, hash);
+
+  NetworkEndian::writeUint32(p, aOffset);
+  p += sizeof(uint32_t);
+
+  char* writeBuffer = mWriteBuf;
+  if (aListener) {
+    mListener = aListener;
+  } else {
+    // We are not going to pass |this| as a callback so the buffer will be
+    // released by CacheFileIOManager. Just null out mWriteBuf here.
+    mWriteBuf = nullptr;
+  }
+
+  rv = CacheFileIOManager::Write(mHandle, aOffset, writeBuffer, p - writeBuffer,
+                                 true, true, aListener ? this : nullptr);
+  if (NS_FAILED(rv)) {
+    LOG(
+        ("CacheFileMetadata::WriteMetadata() - CacheFileIOManager::Write() "
+         "failed synchronously. [this=%p, rv=0x%08" PRIx32 "]",
+         this, static_cast<uint32_t>(rv)));
+
+    mListener = nullptr;
+    if (mWriteBuf) {
+      CacheFileUtils::FreeBuffer(mWriteBuf);
+      mWriteBuf = nullptr;
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  DoMemoryReport(MemoryUsage());
+
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::SyncReadMetadata(nsIFile* aFile) {
+  LOG(("CacheFileMetadata::SyncReadMetadata() [this=%p]", this));
+
+  MOZ_ASSERT(!mListener);
+  MOZ_ASSERT(!mHandle);
+  MOZ_ASSERT(!mHashArray);
+  MOZ_ASSERT(!mBuf);
+  MOZ_ASSERT(!mWriteBuf);
+  MOZ_ASSERT(mKey.IsEmpty());
+
+  nsresult rv;
+
+  int64_t fileSize;
+  rv = aFile->GetFileSize(&fileSize);
+  if (NS_FAILED(rv)) {
+    // Don't bloat the console
+    return rv;
+  }
+
+  PRFileDesc* fd;
+  rv = aFile->OpenNSPRFileDesc(PR_RDONLY, 0600, &fd);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t offset = PR_Seek64(fd, fileSize - sizeof(uint32_t), PR_SEEK_SET);
+  if (offset == -1) {
+    PR_Close(fd);
+    return NS_ERROR_FAILURE;
+  }
+
+  uint32_t metaOffset;
+  int32_t bytesRead = PR_Read(fd, &metaOffset, sizeof(uint32_t));
+  if (bytesRead != sizeof(uint32_t)) {
+    PR_Close(fd);
+    return NS_ERROR_FAILURE;
+  }
+
+  metaOffset = NetworkEndian::readUint32(&metaOffset);
+  if (metaOffset > fileSize) {
+    PR_Close(fd);
+    return NS_ERROR_FAILURE;
+  }
+
+  mBuf = static_cast<char*>(malloc(fileSize - metaOffset));
+  if (!mBuf) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  mBufSize = fileSize - metaOffset;
+
+  DoMemoryReport(MemoryUsage());
+
+  offset = PR_Seek64(fd, metaOffset, PR_SEEK_SET);
+  if (offset == -1) {
+    PR_Close(fd);
+    return NS_ERROR_FAILURE;
+  }
+
+  bytesRead = PR_Read(fd, mBuf, mBufSize);
+  PR_Close(fd);
+  if (bytesRead != static_cast<int32_t>(mBufSize)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  rv = ParseMetadata(metaOffset, 0, false);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+const char* CacheFileMetadata::GetElement(const char* aKey) {
+  const char* data = mBuf;
+  const char* limit = mBuf + mElementsSize;
+
+  while (data != limit) {
+    size_t maxLen = limit - data;
+    size_t keyLen = strnlen(data, maxLen);
+    MOZ_RELEASE_ASSERT(keyLen != maxLen,
+                       "Metadata elements corrupted. Key "
+                       "isn't null terminated!");
+    MOZ_RELEASE_ASSERT(keyLen + 1 != maxLen,
+                       "Metadata elements corrupted. "
+                       "There is no value for the key!");
+
+    const char* value = data + keyLen + 1;
+    maxLen = limit - value;
+    size_t valueLen = strnlen(value, maxLen);
+    MOZ_RELEASE_ASSERT(valueLen != maxLen,
+                       "Metadata elements corrupted. Value "
+                       "isn't null terminated!");
+
+    if (strcmp(data, aKey) == 0) {
+      LOG(("CacheFileMetadata::GetElement() - Key found [this=%p, key=%s]",
+           this, aKey));
+      return value;
+    }
+
+    // point to next pair
+    data += keyLen + valueLen + 2;
+  }
+  LOG(("CacheFileMetadata::GetElement() - Key not found [this=%p, key=%s]",
+       this, aKey));
+  return nullptr;
+}
+
+nsresult CacheFileMetadata::SetElement(const char* aKey, const char* aValue) {
+  LOG(("CacheFileMetadata::SetElement() [this=%p, key=%s, value=%p]", this,
+       aKey, aValue));
+
+  mLock->Lock().AssertCurrentThreadOwns();
+
+  MarkDirty();
+
+  nsresult rv;
+
+  const uint32_t keySize = strlen(aKey) + 1;
+  char* pos = const_cast<char*>(GetElement(aKey));
+
+  if (!aValue) {
+    // No value means remove the key/value pair completely, if existing
+    if (pos) {
+      uint32_t oldValueSize = strlen(pos) + 1;
+      uint32_t offset = pos - mBuf;
+      uint32_t remainder = mElementsSize - (offset + oldValueSize);
+
+      memmove(pos - keySize, pos + oldValueSize, remainder);
+      mElementsSize -= keySize + oldValueSize;
+    }
+    return NS_OK;
+  }
+
+  const uint32_t valueSize = strlen(aValue) + 1;
+  uint32_t newSize = mElementsSize + valueSize;
+  if (pos) {
+    const uint32_t oldValueSize = strlen(pos) + 1;
+    const uint32_t offset = pos - mBuf;
+    const uint32_t remainder = mElementsSize - (offset + oldValueSize);
+
+    // Update the value in place
+    newSize -= oldValueSize;
+    rv = EnsureBuffer(newSize);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    // Move the remainder to the right place
+    pos = mBuf + offset;
+    memmove(pos + valueSize, pos + oldValueSize, remainder);
+  } else {
+    // allocate new meta data element
+    newSize += keySize;
+    rv = EnsureBuffer(newSize);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    // Add after last element
+    pos = mBuf + mElementsSize;
+    memcpy(pos, aKey, keySize);
+    pos += keySize;
+  }
+
+  // Update value
+  memcpy(pos, aValue, valueSize);
+  mElementsSize = newSize;
+
+  return NS_OK;
+}
+
+void CacheFileMetadata::Visit(nsICacheEntryMetaDataVisitor* aVisitor) {
+  const char* data = mBuf;
+  const char* limit = mBuf + mElementsSize;
+
+  while (data < limit) {
+    // Point to the value part
+    const char* value = data + strlen(data) + 1;
+    MOZ_ASSERT(value < limit, "Metadata elements corrupted");
+
+    aVisitor->OnMetaDataElement(data, value);
+
+    // Skip value part
+    data = value + strlen(value) + 1;
+  }
+
+  MOZ_ASSERT(data == limit, "Metadata elements corrupted");
+}
+
+CacheHash::Hash16_t CacheFileMetadata::GetHash(uint32_t aIndex) {
+  mLock->Lock().AssertCurrentThreadOwns();
+
+  MOZ_ASSERT(aIndex < mHashCount);
+  return NetworkEndian::readUint16(&mHashArray[aIndex]);
+}
+
+nsresult CacheFileMetadata::SetHash(uint32_t aIndex,
+                                    CacheHash::Hash16_t aHash) {
+  LOG(("CacheFileMetadata::SetHash() [this=%p, idx=%d, hash=%x]", this, aIndex,
+       aHash));
+
+  mLock->Lock().AssertCurrentThreadOwns();
+
+  MarkDirty();
+
+  MOZ_ASSERT(aIndex <= mHashCount);
+
+  if (aIndex > mHashCount) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  if (aIndex == mHashCount) {
+    if ((aIndex + 1) * sizeof(CacheHash::Hash16_t) > mHashArraySize) {
+      // reallocate hash array buffer
+      if (mHashArraySize == 0) {
+        mHashArraySize = kInitialHashArraySize * sizeof(CacheHash::Hash16_t);
+      } else {
+        mHashArraySize *= 2;
+      }
+      mHashArray = static_cast<CacheHash::Hash16_t*>(
+          moz_xrealloc(mHashArray, mHashArraySize));
+    }
+
+    mHashCount++;
+  }
+
+  NetworkEndian::writeUint16(&mHashArray[aIndex], aHash);
+
+  DoMemoryReport(MemoryUsage());
+
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::RemoveHash(uint32_t aIndex) {
+  LOG(("CacheFileMetadata::RemoveHash() [this=%p, idx=%d]", this, aIndex));
+
+  mLock->Lock().AssertCurrentThreadOwns();
+
+  MarkDirty();
+
+  MOZ_ASSERT((aIndex + 1) == mHashCount, "Can remove only last hash!");
+
+  if (aIndex + 1 != mHashCount) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  mHashCount--;
+  return NS_OK;
+}
+
+void CacheFileMetadata::AddFlags(uint32_t aFlags) {
+  MarkDirty(false);
+  mMetaHdr.mFlags |= aFlags;
+}
+
+void CacheFileMetadata::RemoveFlags(uint32_t aFlags) {
+  MarkDirty(false);
+  mMetaHdr.mFlags &= ~aFlags;
+}
+
+void CacheFileMetadata::SetExpirationTime(uint32_t aExpirationTime) {
+  LOG(("CacheFileMetadata::SetExpirationTime() [this=%p, expirationTime=%d]",
+       this, aExpirationTime));
+
+  MarkDirty(false);
+  mMetaHdr.mExpirationTime = aExpirationTime;
+}
+
+void CacheFileMetadata::SetFrecency(uint32_t aFrecency) {
+  LOG(("CacheFileMetadata::SetFrecency() [this=%p, frecency=%f]", this,
+       (double)aFrecency));
+
+  MarkDirty(false);
+  mMetaHdr.mFrecency = aFrecency;
+}
+
+void CacheFileMetadata::OnFetched() {
+  MarkDirty(false);
+
+  mMetaHdr.mLastFetched = NOW_SECONDS();
+  ++mMetaHdr.mFetchCount;
+}
+
+void CacheFileMetadata::MarkDirty(bool aUpdateLastModified) {
+  mIsDirty = true;
+  if (aUpdateLastModified) {
+    mMetaHdr.mLastModified = NOW_SECONDS();
+  }
+}
+
+nsresult CacheFileMetadata::OnFileOpened(CacheFileHandle* aHandle,
+                                         nsresult aResult) {
+  MOZ_CRASH("CacheFileMetadata::OnFileOpened should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult CacheFileMetadata::OnDataWritten(CacheFileHandle* aHandle,
+                                          const char* aBuf, nsresult aResult) {
+  LOG(
+      ("CacheFileMetadata::OnDataWritten() [this=%p, handle=%p, "
+       "result=0x%08" PRIx32 "]",
+       this, aHandle, static_cast<uint32_t>(aResult)));
+
+  nsCOMPtr<CacheFileMetadataListener> listener;
+  {
+    MutexAutoLock lock(mLock->Lock());
+
+    MOZ_ASSERT(mListener);
+    MOZ_ASSERT(mWriteBuf);
+
+    CacheFileUtils::FreeBuffer(mWriteBuf);
+    mWriteBuf = nullptr;
+
+    mListener.swap(listener);
+    DoMemoryReport(MemoryUsage());
+  }
+
+  listener->OnMetadataWritten(aResult);
+
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::OnDataRead(CacheFileHandle* aHandle, char* aBuf,
+                                       nsresult aResult) {
+  LOG((
+      "CacheFileMetadata::OnDataRead() [this=%p, handle=%p, result=0x%08" PRIx32
+      "]",
+      this, aHandle, static_cast<uint32_t>(aResult)));
+
+  MOZ_ASSERT(mListener);
+
+  nsresult rv;
+  nsCOMPtr<CacheFileMetadataListener> listener;
+
+  auto notifyListenerOutsideLock = mozilla::MakeScopeExit([&listener] {
+    if (listener) {
+      listener->OnMetadataRead(NS_OK);
+    }
+  });
+
+  MutexAutoLock lock(mLock->Lock());
+
+  if (NS_FAILED(aResult)) {
+    LOG(
+        ("CacheFileMetadata::OnDataRead() - CacheFileIOManager::Read() failed"
+         ", creating empty metadata. [this=%p, rv=0x%08" PRIx32 "]",
+         this, static_cast<uint32_t>(aResult)));
+
+    InitEmptyMetadata();
+
+    mListener.swap(listener);
+    return NS_OK;
+  }
+
+  if (mFirstRead) {
+    Telemetry::AccumulateTimeDelta(
+        Telemetry::NETWORK_CACHE_METADATA_FIRST_READ_TIME_MS, mReadStart);
+  } else {
+    Telemetry::AccumulateTimeDelta(
+        Telemetry::NETWORK_CACHE_METADATA_SECOND_READ_TIME_MS, mReadStart);
+  }
+
+  // check whether we have read all necessary data
+  uint32_t realOffset =
+      NetworkEndian::readUint32(mBuf + mBufSize - sizeof(uint32_t));
+
+  int64_t size = mHandle->FileSize();
+  MOZ_ASSERT(size != -1);
+
+  if (realOffset >= size) {
+    LOG(
+        ("CacheFileMetadata::OnDataRead() - Invalid realOffset, creating "
+         "empty metadata. [this=%p, realOffset=%u, size=%" PRId64 "]",
+         this, realOffset, size));
+
+    InitEmptyMetadata();
+
+    mListener.swap(listener);
+    return NS_OK;
+  }
+
+  uint32_t maxHashCount = size / kChunkSize;
+  uint32_t maxMetadataSize = CalcMetadataSize(kMaxElementsSize, maxHashCount);
+  if (size - realOffset > maxMetadataSize) {
+    LOG(
+        ("CacheFileMetadata::OnDataRead() - Invalid realOffset, metadata would "
+         "be too big, creating empty metadata. [this=%p, realOffset=%u, "
+         "maxMetadataSize=%u, size=%" PRId64 "]",
+         this, realOffset, maxMetadataSize, size));
+
+    InitEmptyMetadata();
+
+    mListener.swap(listener);
+    return NS_OK;
+  }
+
+  uint32_t usedOffset = size - mBufSize;
+
+  if (realOffset < usedOffset) {
+    uint32_t missing = usedOffset - realOffset;
+    // we need to read more data
+    char* newBuf = static_cast<char*>(realloc(mBuf, mBufSize + missing));
+    if (!newBuf) {
+      LOG(
+          ("CacheFileMetadata::OnDataRead() - Error allocating %d more bytes "
+           "for the missing part of the metadata, creating empty metadata. "
+           "[this=%p]",
+           missing, this));
+
+      InitEmptyMetadata();
+
+      mListener.swap(listener);
+      return NS_OK;
+    }
+
+    mBuf = newBuf;
+    memmove(mBuf + missing, mBuf, mBufSize);
+    mBufSize += missing;
+
+    DoMemoryReport(MemoryUsage());
+
+    LOG(
+        ("CacheFileMetadata::OnDataRead() - We need to read %d more bytes to "
+         "have full metadata. [this=%p]",
+         missing, this));
+
+    mFirstRead = false;
+    mReadStart = mozilla::TimeStamp::Now();
+    rv = CacheFileIOManager::Read(mHandle, realOffset, mBuf, missing, this);
+    if (NS_FAILED(rv)) {
+      LOG(
+          ("CacheFileMetadata::OnDataRead() - CacheFileIOManager::Read() "
+           "failed synchronously, creating empty metadata. [this=%p, "
+           "rv=0x%08" PRIx32 "]",
+           this, static_cast<uint32_t>(rv)));
+
+      InitEmptyMetadata();
+
+      mListener.swap(listener);
+      return NS_OK;
+    }
+
+    return NS_OK;
+  }
+
+  Telemetry::Accumulate(Telemetry::NETWORK_CACHE_METADATA_SIZE_2,
+                        size - realOffset);
+
+  // We have all data according to offset information at the end of the entry.
+  // Try to parse it.
+  rv = ParseMetadata(realOffset, realOffset - usedOffset, true);
+  if (NS_FAILED(rv)) {
+    LOG(
+        ("CacheFileMetadata::OnDataRead() - Error parsing metadata, creating "
+         "empty metadata. [this=%p]",
+         this));
+    InitEmptyMetadata();
+  } else {
+    // Shrink elements buffer.
+    mBuf = static_cast<char*>(moz_xrealloc(mBuf, mElementsSize));
+    mBufSize = mElementsSize;
+
+    // There is usually no or just one call to SetMetadataElement() when the
+    // metadata is parsed from disk. Avoid allocating power of two sized buffer
+    // which we do in case of newly created metadata.
+    mAllocExactSize = true;
+  }
+
+  mListener.swap(listener);
+
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::OnFileDoomed(CacheFileHandle* aHandle,
+                                         nsresult aResult) {
+  MOZ_CRASH("CacheFileMetadata::OnFileDoomed should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult CacheFileMetadata::OnEOFSet(CacheFileHandle* aHandle,
+                                     nsresult aResult) {
+  MOZ_CRASH("CacheFileMetadata::OnEOFSet should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult CacheFileMetadata::OnFileRenamed(CacheFileHandle* aHandle,
+                                          nsresult aResult) {
+  MOZ_CRASH("CacheFileMetadata::OnFileRenamed should not be called!");
+  return NS_ERROR_UNEXPECTED;
+}
+
+void CacheFileMetadata::InitEmptyMetadata() {
+  if (mBuf) {
+    CacheFileUtils::FreeBuffer(mBuf);
+    mBuf = nullptr;
+    mBufSize = 0;
+  }
+  mAllocExactSize = false;
+  mOffset = 0;
+  mMetaHdr.mVersion = kCacheEntryVersion;
+  mMetaHdr.mFetchCount = 0;
+  mMetaHdr.mExpirationTime = nsICacheEntry::NO_EXPIRATION_TIME;
+  mMetaHdr.mKeySize = mKey.Length();
+
+  // Deliberately not touching the "kCacheEntryIsPinned" flag.
+
+  DoMemoryReport(MemoryUsage());
+
+  // We're creating a new entry. If there is any old data truncate it.
+  if (mHandle) {
+    mHandle->SetPinned(Pinned());
+    // We can pronounce the handle as invalid now, because it simply
+    // doesn't have the correct metadata.  This will cause IO operations
+    // be bypassed during shutdown (mainly dooming it, when a channel
+    // is canceled by closing the window.)
+    mHandle->SetInvalid();
+    if (mHandle->FileExists() && mHandle->FileSize()) {
+      CacheFileIOManager::TruncateSeekSetEOF(mHandle, 0, 0, nullptr);
+    }
+  }
+}
+
+nsresult CacheFileMetadata::ParseMetadata(uint32_t aMetaOffset,
+                                          uint32_t aBufOffset, bool aHaveKey) {
+  LOG(
+      ("CacheFileMetadata::ParseMetadata() [this=%p, metaOffset=%d, "
+       "bufOffset=%d, haveKey=%u]",
+       this, aMetaOffset, aBufOffset, aHaveKey));
+
+  nsresult rv;
+
+  uint32_t metaposOffset = mBufSize - sizeof(uint32_t);
+  uint32_t hashesOffset = aBufOffset + sizeof(uint32_t);
+  uint32_t hashCount = aMetaOffset / kChunkSize;
+  if (aMetaOffset % kChunkSize) hashCount++;
+  uint32_t hashesLen = hashCount * sizeof(CacheHash::Hash16_t);
+  uint32_t hdrOffset = hashesOffset + hashesLen;
+  uint32_t keyOffset = hdrOffset + sizeof(CacheFileMetadataHeader);
+
+  LOG(
+      ("CacheFileMetadata::ParseMetadata() [this=%p]\n  metaposOffset=%d\n  "
+       "hashesOffset=%d\n  hashCount=%d\n  hashesLen=%d\n  hdfOffset=%d\n  "
+       "keyOffset=%d\n",
+       this, metaposOffset, hashesOffset, hashCount, hashesLen, hdrOffset,
+       keyOffset));
+
+  if (keyOffset > metaposOffset) {
+    LOG(("CacheFileMetadata::ParseMetadata() - Wrong keyOffset! [this=%p]",
+         this));
+    return NS_ERROR_FILE_CORRUPTED;
+  }
+
+  mMetaHdr.ReadFromBuf(mBuf + hdrOffset);
+
+  if (mMetaHdr.mVersion == 1) {
+    // Backward compatibility before we've added flags to the header
+    keyOffset -= sizeof(uint32_t);
+  } else if (mMetaHdr.mVersion == 2) {
+    // Version 2 just lacks the ability to store alternative data. Nothing to do
+    // here.
+  } else if (mMetaHdr.mVersion != kCacheEntryVersion) {
+    LOG(
+        ("CacheFileMetadata::ParseMetadata() - Not a version we understand to. "
+         "[version=0x%x, this=%p]",
+         mMetaHdr.mVersion, this));
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // Update the version stored in the header to make writes
+  // store the header in the current version form.
+  mMetaHdr.mVersion = kCacheEntryVersion;
+
+  uint32_t elementsOffset = mMetaHdr.mKeySize + keyOffset + 1;
+
+  if (elementsOffset > metaposOffset) {
+    LOG(
+        ("CacheFileMetadata::ParseMetadata() - Wrong elementsOffset %d "
+         "[this=%p]",
+         elementsOffset, this));
+    return NS_ERROR_FILE_CORRUPTED;
+  }
+
+  // check that key ends with \0
+  if (mBuf[elementsOffset - 1] != 0) {
+    LOG(
+        ("CacheFileMetadata::ParseMetadata() - Elements not null terminated. "
+         "[this=%p]",
+         this));
+    return NS_ERROR_FILE_CORRUPTED;
+  }
+
+  if (!aHaveKey) {
+    // get the key form metadata
+    mKey.Assign(mBuf + keyOffset, mMetaHdr.mKeySize);
+
+    rv = ParseKey(mKey);
+    if (NS_FAILED(rv)) return rv;
+  } else {
+    if (mMetaHdr.mKeySize != mKey.Length()) {
+      LOG(
+          ("CacheFileMetadata::ParseMetadata() - Key collision (1), key=%s "
+           "[this=%p]",
+           nsCString(mBuf + keyOffset, mMetaHdr.mKeySize).get(), this));
+      return NS_ERROR_FILE_CORRUPTED;
+    }
+
+    if (memcmp(mKey.get(), mBuf + keyOffset, mKey.Length()) != 0) {
+      LOG(
+          ("CacheFileMetadata::ParseMetadata() - Key collision (2), key=%s "
+           "[this=%p]",
+           nsCString(mBuf + keyOffset, mMetaHdr.mKeySize).get(), this));
+      return NS_ERROR_FILE_CORRUPTED;
+    }
+  }
+
+  // check metadata hash (data from hashesOffset to metaposOffset)
+  CacheHash::Hash32_t hashComputed, hashExpected;
+  hashComputed =
+      CacheHash::Hash(mBuf + hashesOffset, metaposOffset - hashesOffset);
+  hashExpected = NetworkEndian::readUint32(mBuf + aBufOffset);
+
+  if (hashComputed != hashExpected) {
+    LOG(
+        ("CacheFileMetadata::ParseMetadata() - Metadata hash mismatch! Hash of "
+         "the metadata is %x, hash in file is %x [this=%p]",
+         hashComputed, hashExpected, this));
+    return NS_ERROR_FILE_CORRUPTED;
+  }
+
+  // check elements
+  rv = CheckElements(mBuf + elementsOffset, metaposOffset - elementsOffset);
+  if (NS_FAILED(rv)) return rv;
+
+  if (mHandle) {
+    if (!mHandle->SetPinned(Pinned())) {
+      LOG(
+          ("CacheFileMetadata::ParseMetadata() - handle was doomed for this "
+           "pinning state, truncate the file [this=%p, pinned=%d]",
+           this, Pinned()));
+      return NS_ERROR_FILE_CORRUPTED;
+    }
+  }
+
+  mHashArraySize = hashesLen;
+  mHashCount = hashCount;
+  if (mHashArraySize) {
+    mHashArray = static_cast<CacheHash::Hash16_t*>(moz_xmalloc(mHashArraySize));
+    memcpy(mHashArray, mBuf + hashesOffset, mHashArraySize);
+  }
+
+  MarkDirty();
+
+  mElementsSize = metaposOffset - elementsOffset;
+  memmove(mBuf, mBuf + elementsOffset, mElementsSize);
+  mOffset = aMetaOffset;
+
+  DoMemoryReport(MemoryUsage());
+
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::CheckElements(const char* aBuf, uint32_t aSize) {
+  if (aSize) {
+    // Check if the metadata ends with a zero byte.
+    if (aBuf[aSize - 1] != 0) {
+      NS_ERROR("Metadata elements are not null terminated");
+      LOG(
+          ("CacheFileMetadata::CheckElements() - Elements are not null "
+           "terminated. [this=%p]",
+           this));
+      return NS_ERROR_FILE_CORRUPTED;
+    }
+    // Check that there are an even number of zero bytes
+    // to match the pattern { key \0 value \0 }
+    bool odd = false;
+    for (uint32_t i = 0; i < aSize; i++) {
+      if (aBuf[i] == 0) odd = !odd;
+    }
+    if (odd) {
+      NS_ERROR("Metadata elements are malformed");
+      LOG(
+          ("CacheFileMetadata::CheckElements() - Elements are malformed. "
+           "[this=%p]",
+           this));
+      return NS_ERROR_FILE_CORRUPTED;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::EnsureBuffer(uint32_t aSize) {
+  if (aSize > kMaxElementsSize) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (mBufSize < aSize) {
+    if (mAllocExactSize) {
+      // If this is not the only allocation, use power of two for following
+      // allocations.
+      mAllocExactSize = false;
+    } else {
+      // find smallest power of 2 greater than or equal to aSize
+      --aSize;
+      aSize |= aSize >> 1;
+      aSize |= aSize >> 2;
+      aSize |= aSize >> 4;
+      aSize |= aSize >> 8;
+      aSize |= aSize >> 16;
+      ++aSize;
+    }
+
+    if (aSize < kInitialBufSize) {
+      aSize = kInitialBufSize;
+    }
+
+    char* newBuf = static_cast<char*>(realloc(mBuf, aSize));
+    if (!newBuf) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    mBufSize = aSize;
+    mBuf = newBuf;
+
+    DoMemoryReport(MemoryUsage());
+  }
+
+  return NS_OK;
+}
+
+nsresult CacheFileMetadata::ParseKey(const nsACString& aKey) {
+  nsCOMPtr<nsILoadContextInfo> info = CacheFileUtils::ParseKey(aKey);
+  NS_ENSURE_TRUE(info, NS_ERROR_FAILURE);
+
+  mAnonymous = info->IsAnonymous();
+  mOriginAttributes = *info->OriginAttributesPtr();
+
+  return NS_OK;
+}
+
+// Memory reporting
+
+size_t CacheFileMetadata::SizeOfExcludingThis(
+    mozilla::MallocSizeOf mallocSizeOf) const {
+  size_t n = 0;
+  // mHandle reported via CacheFileIOManager.
+  n += mKey.SizeOfExcludingThisIfUnshared(mallocSizeOf);
+  n += mallocSizeOf(mHashArray);
+  n += mallocSizeOf(mBuf);
+  // Ignore mWriteBuf, it's not safe to access it when metadata is being
+  // written and it's null otherwise.
+  // mListener is usually the owning CacheFile.
+
+  return n;
+}
+
+size_t CacheFileMetadata::SizeOfIncludingThis(
+    mozilla::MallocSizeOf mallocSizeOf) const {
+  return mallocSizeOf(this) + SizeOfExcludingThis(mallocSizeOf);
+}
+
+}  // namespace mozilla::net