1 files changed, 243 insertions, 0 deletions
diff --git a/dom/file/ipc/RemoteLazyInputStreamStorage.cpp b/dom/file/ipc/RemoteLazyInputStreamStorage.cpp
new file mode 100644
index 0000000000..8ce2c22657
--- /dev/null
+++ b/dom/file/ipc/RemoteLazyInputStreamStorage.cpp
@@ -0,0 +1,243 @@
+/* -*- 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/SlicedInputStream.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/StaticMutex.h"
+#include "mozilla/StaticPtr.h"
+#include "nsIPropertyBag2.h"
+#include "nsStreamUtils.h"
+#include "RemoteLazyInputStreamParent.h"
+#include "RemoteLazyInputStreamStorage.h"
+
+namespace mozilla {
+
+using namespace hal;
+
+extern mozilla::LazyLogModule gRemoteLazyStreamLog;
+
+namespace {
+StaticMutex gMutex;
+StaticRefPtr<RemoteLazyInputStreamStorage> gStorage;
+}  // namespace
+
+NS_INTERFACE_MAP_BEGIN(RemoteLazyInputStreamStorage)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIObserver)
+  NS_INTERFACE_MAP_ENTRY(nsIObserver)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_ADDREF(RemoteLazyInputStreamStorage)
+NS_IMPL_RELEASE(RemoteLazyInputStreamStorage)
+
+/* static */
+Result<RefPtr<RemoteLazyInputStreamStorage>, nsresult>
+RemoteLazyInputStreamStorage::Get() {
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  if (gStorage) {
+    RefPtr<RemoteLazyInputStreamStorage> storage = gStorage;
+    return storage;
+  }
+
+  return Err(NS_ERROR_NOT_INITIALIZED);
+}
+
+/* static */
+void RemoteLazyInputStreamStorage::Initialize() {
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  MOZ_ASSERT(!gStorage);
+
+  gStorage = new RemoteLazyInputStreamStorage();
+
+  MOZ_ALWAYS_SUCCEEDS(NS_CreateBackgroundTaskQueue(
+      "RemoteLazyInputStreamStorage", getter_AddRefs(gStorage->mTaskQueue)));
+
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->AddObserver(gStorage, "xpcom-shutdown", false);
+  }
+}
+
+NS_IMETHODIMP
+RemoteLazyInputStreamStorage::Observe(nsISupports* aSubject, const char* aTopic,
+                                      const char16_t* aData) {
+  MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));
+
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(this, "xpcom-shutdown");
+  }
+
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  gStorage = nullptr;
+  return NS_OK;
+}
+
+void RemoteLazyInputStreamStorage::AddStream(nsIInputStream* aInputStream,
+                                             const nsID& aID) {
+  MOZ_ASSERT(aInputStream);
+
+  MOZ_LOG(
+      gRemoteLazyStreamLog, LogLevel::Verbose,
+      ("Storage::AddStream(%s) = %p", nsIDToCString(aID).get(), aInputStream));
+
+  UniquePtr<StreamData> data = MakeUnique<StreamData>();
+  data->mInputStream = aInputStream;
+
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  mStorage.InsertOrUpdate(aID, std::move(data));
+}
+
+nsCOMPtr<nsIInputStream> RemoteLazyInputStreamStorage::ForgetStream(
+    const nsID& aID) {
+  MOZ_LOG(gRemoteLazyStreamLog, LogLevel::Verbose,
+          ("Storage::ForgetStream(%s)", nsIDToCString(aID).get()));
+
+  UniquePtr<StreamData> entry;
+
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  mStorage.Remove(aID, &entry);
+
+  if (!entry) {
+    return nullptr;
+  }
+
+  return std::move(entry->mInputStream);
+}
+
+bool RemoteLazyInputStreamStorage::HasStream(const nsID& aID) {
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  StreamData* data = mStorage.Get(aID);
+  return !!data;
+}
+
+void RemoteLazyInputStreamStorage::GetStream(const nsID& aID, uint64_t aStart,
+                                             uint64_t aLength,
+                                             nsIInputStream** aInputStream) {
+  *aInputStream = nullptr;
+
+  MOZ_LOG(gRemoteLazyStreamLog, LogLevel::Verbose,
+          ("Storage::GetStream(%s, %" PRIu64 " %" PRIu64 ")",
+           nsIDToCString(aID).get(), aStart, aLength));
+
+  nsCOMPtr<nsIInputStream> inputStream;
+
+  // NS_CloneInputStream cannot be called when the mutex is locked because it
+  // can, recursively call GetStream() in case the child actor lives on the
+  // parent process.
+  {
+    mozilla::StaticMutexAutoLock lock(gMutex);
+    StreamData* data = mStorage.Get(aID);
+    if (!data) {
+      return;
+    }
+
+    inputStream = data->mInputStream;
+  }
+
+  MOZ_ASSERT(inputStream);
+
+  // We cannot return always the same inputStream because not all of them are
+  // able to be reused. Better to clone them.
+
+  nsCOMPtr<nsIInputStream> clonedStream;
+  nsCOMPtr<nsIInputStream> replacementStream;
+
+  nsresult rv = NS_CloneInputStream(inputStream, getter_AddRefs(clonedStream),
+                                    getter_AddRefs(replacementStream));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
+
+  if (replacementStream) {
+    mozilla::StaticMutexAutoLock lock(gMutex);
+    StreamData* data = mStorage.Get(aID);
+    // data can be gone in the meantime.
+    if (!data) {
+      return;
+    }
+
+    data->mInputStream = replacementStream;
+  }
+
+  // Now it's the right time to apply a slice if needed.
+  if (aStart > 0 || aLength < UINT64_MAX) {
+    clonedStream =
+        new SlicedInputStream(clonedStream.forget(), aStart, aLength);
+  }
+
+  clonedStream.forget(aInputStream);
+}
+
+void RemoteLazyInputStreamStorage::StoreCallback(
+    const nsID& aID, RemoteLazyInputStreamParentCallback* aCallback) {
+  MOZ_ASSERT(aCallback);
+
+  MOZ_LOG(
+      gRemoteLazyStreamLog, LogLevel::Verbose,
+      ("Storage::StoreCallback(%s, %p)", nsIDToCString(aID).get(), aCallback));
+
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  StreamData* data = mStorage.Get(aID);
+  if (data) {
+    MOZ_ASSERT(!data->mCallback);
+    data->mCallback = aCallback;
+  }
+}
+
+already_AddRefed<RemoteLazyInputStreamParentCallback>
+RemoteLazyInputStreamStorage::TakeCallback(const nsID& aID) {
+  MOZ_LOG(gRemoteLazyStreamLog, LogLevel::Verbose,
+          ("Storage::TakeCallback(%s)", nsIDToCString(aID).get()));
+
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  StreamData* data = mStorage.Get(aID);
+  if (!data) {
+    return nullptr;
+  }
+
+  RefPtr<RemoteLazyInputStreamParentCallback> callback;
+  data->mCallback.swap(callback);
+  return callback.forget();
+}
+
+void RemoteLazyInputStreamStorage::ActorCreated(const nsID& aID) {
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  StreamData* data = mStorage.Get(aID);
+  if (!data) {
+    return;
+  }
+
+  size_t count = ++data->mActorCount;
+
+  MOZ_LOG(gRemoteLazyStreamLog, LogLevel::Verbose,
+          ("Storage::ActorCreated(%s) = %zu", nsIDToCString(aID).get(), count));
+}
+
+void RemoteLazyInputStreamStorage::ActorDestroyed(const nsID& aID) {
+  UniquePtr<StreamData> entry;
+  {
+    mozilla::StaticMutexAutoLock lock(gMutex);
+    StreamData* data = mStorage.Get(aID);
+    if (!data) {
+      return;
+    }
+
+    auto newCount = --data->mActorCount;
+    MOZ_LOG(gRemoteLazyStreamLog, LogLevel::Verbose,
+            ("Storage::ActorDestroyed(%s) = %zu (cb=%p)",
+             nsIDToCString(aID).get(), newCount, data->mCallback.get()));
+
+    if (newCount == 0) {
+      mStorage.Remove(aID, &entry);
+    }
+  }
+
+  if (entry && entry->mCallback) {
+    entry->mCallback->ActorDestroyed(aID);
+  }
+}
+
+}  // namespace mozilla