1 files changed, 136 insertions, 0 deletions
diff --git a/dom/file/MutableBlobStorage.h b/dom/file/MutableBlobStorage.h
new file mode 100644
index 0000000000..aa0d42c75e
--- /dev/null
+++ b/dom/file/MutableBlobStorage.h
@@ -0,0 +1,136 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_MutableBlobStorage_h
+#define mozilla_dom_MutableBlobStorage_h
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/Mutex.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "prio.h"
+
+class nsIEventTarget;
+class nsIRunnable;
+
+namespace mozilla {
+
+class TaskQueue;
+
+namespace dom {
+
+class Blob;
+class BlobImpl;
+class MutableBlobStorage;
+class TemporaryIPCBlobChild;
+class TemporaryIPCBlobChildCallback;
+
+class MutableBlobStorageCallback {
+ public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  virtual void BlobStoreCompleted(MutableBlobStorage* aBlobStorage,
+                                  BlobImpl* aBlob, nsresult aRv) = 0;
+};
+
+// This class is must be created and used on main-thread, except for Append()
+// that can be called on any thread.
+class MutableBlobStorage final {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MutableBlobStorage)
+
+  enum MutableBlobStorageType {
+    eOnlyInMemory,
+    eCouldBeInTemporaryFile,
+  };
+
+  explicit MutableBlobStorage(MutableBlobStorageType aType,
+                              nsIEventTarget* aEventTarget = nullptr,
+                              uint32_t aMaxMemory = 0);
+
+  nsresult Append(const void* aData, uint32_t aLength);
+
+  // This method can be called just once.
+  // The callback will be called when the BlobImpl is ready.
+  void GetBlobImplWhenReady(const nsACString& aContentType,
+                            MutableBlobStorageCallback* aCallback);
+
+  void TemporaryFileCreated(PRFileDesc* aFD);
+
+  void AskForBlob(TemporaryIPCBlobChildCallback* aCallback,
+                  const nsACString& aContentType);
+
+  void ErrorPropagated(nsresult aRv);
+
+  nsIEventTarget* EventTarget() {
+    MOZ_ASSERT(mEventTarget);
+    return mEventTarget;
+  }
+
+  // Returns the heap size in bytes of our internal buffers.
+  // Note that this intentionally ignores the data in the temp file.
+  size_t SizeOfCurrentMemoryBuffer();
+
+  PRFileDesc* GetFD();
+
+  void CloseFD();
+
+ private:
+  ~MutableBlobStorage();
+
+  bool ExpandBufferSize(const MutexAutoLock& aProofOfLock, uint64_t aSize);
+
+  bool ShouldBeTemporaryStorage(const MutexAutoLock& aProofOfLock,
+                                uint64_t aSize) const;
+
+  bool MaybeCreateTemporaryFile(const MutexAutoLock& aProofOfLock);
+  void MaybeCreateTemporaryFileOnMainThread(const MutexAutoLock& aProofOfLock);
+
+  [[nodiscard]] nsresult DispatchToIOThread(
+      already_AddRefed<nsIRunnable> aRunnable);
+
+  Mutex mMutex MOZ_UNANNOTATED;
+
+  // All these variables are touched on the main thread only or in the
+  // retargeted thread when used by Append(). They are protected by mMutex.
+
+  void* mData;
+  uint64_t mDataLen;
+  uint64_t mDataBufferLen;
+
+  enum StorageState {
+    eKeepInMemory,
+    eInMemory,
+    eWaitingForTemporaryFile,
+    eInTemporaryFile,
+    eClosed
+  };
+
+  StorageState mStorageState;
+
+  PRFileDesc* mFD;
+
+  nsresult mErrorResult;
+
+  RefPtr<TaskQueue> mTaskQueue;
+  nsCOMPtr<nsIEventTarget> mEventTarget;
+
+  nsCString mPendingContentType;
+  RefPtr<MutableBlobStorageCallback> mPendingCallback;
+
+  RefPtr<TemporaryIPCBlobChild> mActor;
+
+  // This value is used when we go from eInMemory to eWaitingForTemporaryFile
+  // and eventually eInTemporaryFile. If the size of the buffer is >=
+  // mMaxMemory, the creation of the temporary file will start.
+  // It's not used if mStorageState is eKeepInMemory.
+  uint32_t mMaxMemory;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_MutableBlobStorage_h