diff options
Diffstat (limited to 'xpcom/io/InputStreamLengthHelper.cpp')
| -rw-r--r-- | xpcom/io/InputStreamLengthHelper.cpp | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/xpcom/io/InputStreamLengthHelper.cpp b/xpcom/io/InputStreamLengthHelper.cpp new file mode 100644 index 0000000000..9a767f9229 --- /dev/null +++ b/xpcom/io/InputStreamLengthHelper.cpp @@ -0,0 +1,258 @@ +/* -*- 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 "InputStreamLengthHelper.h" +#include "mozilla/dom/WorkerCommon.h" +#include "nsIAsyncInputStream.h" +#include "nsIInputStream.h" +#include "nsNetCID.h" +#include "nsServiceManagerUtils.h" + +namespace mozilla { + +namespace { + +class AvailableEvent final : public Runnable { + public: + AvailableEvent(nsIInputStream* stream, + const std::function<void(int64_t aLength)>& aCallback) + : Runnable("mozilla::AvailableEvent"), + mStream(stream), + mCallback(aCallback), + mSize(-1) { + mCallbackTarget = GetCurrentSerialEventTarget(); + MOZ_ASSERT(NS_IsMainThread()); + } + + NS_IMETHOD + Run() override { + // ping + if (!NS_IsMainThread()) { + uint64_t size = 0; + if (NS_WARN_IF(NS_FAILED(mStream->Available(&size)))) { + mSize = -1; + } else { + mSize = (int64_t)size; + } + + mStream = nullptr; + + nsCOMPtr<nsIRunnable> self(this); // overly cute + mCallbackTarget->Dispatch(self.forget(), NS_DISPATCH_NORMAL); + mCallbackTarget = nullptr; + return NS_OK; + } + + // pong + std::function<void(int64_t aLength)> callback; + callback.swap(mCallback); + callback(mSize); + return NS_OK; + } + + private: + nsCOMPtr<nsIInputStream> mStream; + std::function<void(int64_t aLength)> mCallback; + nsCOMPtr<nsIEventTarget> mCallbackTarget; + + int64_t mSize; +}; + +} // namespace + +/* static */ +bool InputStreamLengthHelper::GetSyncLength(nsIInputStream* aStream, + int64_t* aLength) { + MOZ_ASSERT(aStream); + MOZ_ASSERT(aLength); + + *aLength = -1; + + // Sync length access. + nsCOMPtr<nsIInputStreamLength> streamLength = do_QueryInterface(aStream); + if (streamLength) { + int64_t length = -1; + nsresult rv = streamLength->Length(&length); + + // All good! + if (NS_SUCCEEDED(rv)) { + *aLength = length; + return true; + } + + // Already closed stream or an error occurred. + if (rv == NS_BASE_STREAM_CLOSED || + NS_WARN_IF(rv == NS_ERROR_NOT_AVAILABLE) || + NS_WARN_IF(rv != NS_BASE_STREAM_WOULD_BLOCK)) { + return true; + } + } + + nsCOMPtr<nsIAsyncInputStreamLength> asyncStreamLength = + do_QueryInterface(aStream); + if (asyncStreamLength) { + // GetAsyncLength should be used. + return false; + } + + // We cannot calculate the length of an async stream. + nsCOMPtr<nsIAsyncInputStream> asyncStream = do_QueryInterface(aStream); + if (asyncStream) { + return false; + } + + // For main-thread only, we want to avoid calling ::Available() for blocking + // streams. + if (NS_IsMainThread()) { + bool nonBlocking = false; + if (NS_WARN_IF(NS_FAILED(aStream->IsNonBlocking(&nonBlocking)))) { + // Let's return -1. There is nothing else we can do here. + return true; + } + + if (!nonBlocking) { + return false; + } + } + + // Fallback using available(). + uint64_t available = 0; + nsresult rv = aStream->Available(&available); + if (NS_WARN_IF(NS_FAILED(rv))) { + // Let's return -1. There is nothing else we can do here. + return true; + } + + *aLength = (int64_t)available; + return true; +} + +/* static */ +void InputStreamLengthHelper::GetAsyncLength( + nsIInputStream* aStream, + const std::function<void(int64_t aLength)>& aCallback) { + MOZ_ASSERT(aStream); + MOZ_ASSERT(aCallback); + + // We don't want to allow this class to be used on workers because we are not + // using the correct Runnable types. + MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread() || + !dom::IsCurrentThreadRunningWorker()); + + RefPtr<InputStreamLengthHelper> helper = + new InputStreamLengthHelper(aStream, aCallback); + + // Let's be sure that we don't call ::Available() on main-thread. + if (NS_IsMainThread()) { + nsCOMPtr<nsIInputStreamLength> streamLength = do_QueryInterface(aStream); + nsCOMPtr<nsIAsyncInputStreamLength> asyncStreamLength = + do_QueryInterface(aStream); + if (!streamLength && !asyncStreamLength) { + // We cannot calculate the length of an async stream. We must fix the + // caller if this happens. +#ifdef DEBUG + nsCOMPtr<nsIAsyncInputStream> asyncStream = do_QueryInterface(aStream); + MOZ_DIAGNOSTIC_ASSERT(!asyncStream); +#endif + + bool nonBlocking = false; + if (NS_SUCCEEDED(aStream->IsNonBlocking(&nonBlocking)) && !nonBlocking) { + nsCOMPtr<nsIEventTarget> target = + do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID); + MOZ_ASSERT(target); + + RefPtr<AvailableEvent> event = new AvailableEvent(aStream, aCallback); + target->Dispatch(event.forget(), NS_DISPATCH_NORMAL); + return; + } + } + } + + // Let's go async in order to have similar behaviors for sync and async + // nsIInputStreamLength implementations. + GetCurrentSerialEventTarget()->Dispatch(helper, NS_DISPATCH_NORMAL); +} + +InputStreamLengthHelper::InputStreamLengthHelper( + nsIInputStream* aStream, + const std::function<void(int64_t aLength)>& aCallback) + : Runnable("InputStreamLengthHelper"), + mStream(aStream), + mCallback(aCallback) { + MOZ_ASSERT(aStream); + MOZ_ASSERT(aCallback); +} + +InputStreamLengthHelper::~InputStreamLengthHelper() = default; + +NS_IMETHODIMP +InputStreamLengthHelper::Run() { + // Sync length access. + nsCOMPtr<nsIInputStreamLength> streamLength = do_QueryInterface(mStream); + if (streamLength) { + int64_t length = -1; + nsresult rv = streamLength->Length(&length); + + // All good! + if (NS_SUCCEEDED(rv)) { + ExecCallback(length); + return NS_OK; + } + + // Already closed stream or an error occurred. + if (rv == NS_BASE_STREAM_CLOSED || + NS_WARN_IF(rv == NS_ERROR_NOT_AVAILABLE) || + NS_WARN_IF(rv != NS_BASE_STREAM_WOULD_BLOCK)) { + ExecCallback(-1); + return NS_OK; + } + } + + // Async length access. + nsCOMPtr<nsIAsyncInputStreamLength> asyncStreamLength = + do_QueryInterface(mStream); + if (asyncStreamLength) { + nsresult rv = + asyncStreamLength->AsyncLengthWait(this, GetCurrentSerialEventTarget()); + if (NS_WARN_IF(NS_FAILED(rv))) { + ExecCallback(-1); + } + + return NS_OK; + } + + // Fallback using available(). + uint64_t available = 0; + nsresult rv = mStream->Available(&available); + if (NS_WARN_IF(NS_FAILED(rv))) { + ExecCallback(-1); + return NS_OK; + } + + ExecCallback((int64_t)available); + return NS_OK; +} + +NS_IMETHODIMP +InputStreamLengthHelper::OnInputStreamLengthReady( + nsIAsyncInputStreamLength* aStream, int64_t aLength) { + ExecCallback(aLength); + return NS_OK; +} + +void InputStreamLengthHelper::ExecCallback(int64_t aLength) { + MOZ_ASSERT(mCallback); + + std::function<void(int64_t aLength)> callback; + callback.swap(mCallback); + + callback(aLength); +} + +NS_IMPL_ISUPPORTS_INHERITED(InputStreamLengthHelper, Runnable, + nsIInputStreamLengthCallback) + +} // namespace mozilla |