jpayne@69: // Copyright (c) 2016 Sandstorm Development Group, Inc. and contributors
jpayne@69: // Licensed under the MIT License:
jpayne@69: //
jpayne@69: // Permission is hereby granted, free of charge, to any person obtaining a copy
jpayne@69: // of this software and associated documentation files (the "Software"), to deal
jpayne@69: // in the Software without restriction, including without limitation the rights
jpayne@69: // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
jpayne@69: // copies of the Software, and to permit persons to whom the Software is
jpayne@69: // furnished to do so, subject to the following conditions:
jpayne@69: //
jpayne@69: // The above copyright notice and this permission notice shall be included in
jpayne@69: // all copies or substantial portions of the Software.
jpayne@69: //
jpayne@69: // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
jpayne@69: // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
jpayne@69: // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
jpayne@69: // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
jpayne@69: // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
jpayne@69: // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
jpayne@69: // THE SOFTWARE.
jpayne@69: 
jpayne@69: #pragma once
jpayne@69: 
jpayne@69: #include <kj/async-io.h>
jpayne@69: 
jpayne@69: KJ_BEGIN_HEADER
jpayne@69: 
jpayne@69: namespace kj {
jpayne@69: 
jpayne@69: class ReadyInputStreamWrapper {
jpayne@69:   // Provides readiness-based Async I/O as a wrapper around KJ's standard completion-based API, for
jpayne@69:   // compatibility with libraries that use readiness-based abstractions (e.g. OpenSSL).
jpayne@69:   //
jpayne@69:   // Unfortunately this requires buffering, so is not very efficient.
jpayne@69: 
jpayne@69: public:
jpayne@69:   ReadyInputStreamWrapper(AsyncInputStream& input);
jpayne@69:   ~ReadyInputStreamWrapper() noexcept(false);
jpayne@69:   KJ_DISALLOW_COPY_AND_MOVE(ReadyInputStreamWrapper);
jpayne@69: 
jpayne@69:   kj::Maybe<size_t> read(kj::ArrayPtr<byte> dst);
jpayne@69:   // Reads bytes into `dst`, returning the number of bytes read. Returns zero only at EOF. Returns
jpayne@69:   // nullptr if not ready.
jpayne@69: 
jpayne@69:   kj::Promise<void> whenReady();
jpayne@69:   // Returns a promise that resolves when read() will return non-null.
jpayne@69: 
jpayne@69:   bool isAtEnd() { return eof; }
jpayne@69:   // Returns true if read() would return zero.
jpayne@69: 
jpayne@69: private:
jpayne@69:   AsyncInputStream& input;
jpayne@69:   kj::ForkedPromise<void> pumpTask = nullptr;
jpayne@69:   bool isPumping = false;
jpayne@69:   bool eof = false;
jpayne@69: 
jpayne@69:   kj::ArrayPtr<const byte> content = nullptr;  // Points to currently-valid part of `buffer`.
jpayne@69:   byte buffer[8192];
jpayne@69: };
jpayne@69: 
jpayne@69: class ReadyOutputStreamWrapper {
jpayne@69:   // Provides readiness-based Async I/O as a wrapper around KJ's standard completion-based API, for
jpayne@69:   // compatibility with libraries that use readiness-based abstractions (e.g. OpenSSL).
jpayne@69:   //
jpayne@69:   // Unfortunately this requires buffering, so is not very efficient.
jpayne@69: 
jpayne@69: public:
jpayne@69:   ReadyOutputStreamWrapper(AsyncOutputStream& output);
jpayne@69:   ~ReadyOutputStreamWrapper() noexcept(false);
jpayne@69:   KJ_DISALLOW_COPY_AND_MOVE(ReadyOutputStreamWrapper);
jpayne@69: 
jpayne@69:   kj::Maybe<size_t> write(kj::ArrayPtr<const byte> src);
jpayne@69:   // Writes bytes from `src`, returning the number of bytes written. Never returns zero for
jpayne@69:   // a non-empty `src`. Returns nullptr if not ready.
jpayne@69: 
jpayne@69:   kj::Promise<void> whenReady();
jpayne@69:   // Returns a promise that resolves when write() will return non-null.
jpayne@69: 
jpayne@69:   class Cork;
jpayne@69:   // An object that, when destructed, will uncork its parent stream.
jpayne@69: 
jpayne@69:   Cork cork();
jpayne@69:   // After calling, data won't be pumped until either the internal buffer fills up or the returned
jpayne@69:   // object is destructed. Use this if you know multiple small write() calls will be happening in
jpayne@69:   // the near future and want to flush them all at once.
jpayne@69:   // Once the returned object is destructed, behavior goes back to normal. The returned object
jpayne@69:   // must be destructed before the ReadyOutputStreamWrapper.
jpayne@69:   // TODO(perf): This is an ugly hack to avoid sending lots of tiny packets when using TLS, which
jpayne@69:   // has to work around OpenSSL's readiness-based I/O layer. We could certainly do better here.
jpayne@69: 
jpayne@69: private:
jpayne@69:   AsyncOutputStream& output;
jpayne@69:   ArrayPtr<const byte> segments[2];
jpayne@69:   kj::ForkedPromise<void> pumpTask = nullptr;
jpayne@69:   bool isPumping = false;
jpayne@69:   bool corked = false;
jpayne@69: 
jpayne@69:   uint start = 0;   // index of first byte
jpayne@69:   uint filled = 0;  // number of bytes currently in buffer
jpayne@69: 
jpayne@69:   byte buffer[8192];
jpayne@69: 
jpayne@69:   void uncork();
jpayne@69: 
jpayne@69:   kj::Promise<void> pump();
jpayne@69:   // Asynchronously push the buffer out to the underlying stream.
jpayne@69: };
jpayne@69: 
jpayne@69: class ReadyOutputStreamWrapper::Cork {
jpayne@69:   // An object that, when destructed, will uncork its parent stream.
jpayne@69: public:
jpayne@69:   ~Cork() {
jpayne@69:     KJ_IF_MAYBE(p, parent) {
jpayne@69:       p->uncork();
jpayne@69:     }
jpayne@69:   }
jpayne@69:   Cork(Cork&& other) : parent(kj::mv(other.parent)) {
jpayne@69:     other.parent = nullptr;
jpayne@69:   }
jpayne@69:   KJ_DISALLOW_COPY(Cork);
jpayne@69: 
jpayne@69: private:
jpayne@69:   Cork(ReadyOutputStreamWrapper& parent) : parent(parent) {}
jpayne@69: 
jpayne@69:   kj::Maybe<ReadyOutputStreamWrapper&> parent;
jpayne@69:   friend class ReadyOutputStreamWrapper;
jpayne@69: };
jpayne@69: 
jpayne@69: } // namespace kj
jpayne@69: 
jpayne@69: KJ_END_HEADER