/* * Copyright (C) 1996-2023 The Squid Software Foundation and contributors * * Squid software is distributed under GPLv2+ license and includes * contributions from numerous individuals and organizations. * Please see the COPYING and CONTRIBUTORS files for details. */ #ifndef SQUID_SRC_PIPELINE_H #define SQUID_SRC_PIPELINE_H #include "base/RefCount.h" #include "http/Stream.h" #include /** * A queue of transactions awaiting completion. * * Transactions in the queue may be fully processed, but not yet delivered, * or only partially processed. * * - HTTP/1 pipelined requests can be processed out of order but * responses MUST be written to the client in-order. * The front() context is for the response writing transaction. * The back context may still be reading a request payload/body. * Other contexts are in deferred I/O state, but may be accumulating * payload/body data to be written later. * * - HTTP/2 multiplexed streams can be processed and delivered in any order. * * For consistency we treat the pipeline as a FIFO queue in both cases. */ class Pipeline { Pipeline(const Pipeline &) = delete; Pipeline & operator =(const Pipeline &) = delete; public: Pipeline() : nrequests(0) {} ~Pipeline() = default; /// register a new request context to the pipeline void add(const Http::StreamPointer &); /// get the first request context in the pipeline Http::StreamPointer front() const; /// get the last request context in the pipeline Http::StreamPointer back() const; /// how many requests are currently pipelined size_t count() const {return requests.size();} /// whether there are none or any requests currently pipelined bool empty() const {return requests.empty();} /// deregister the front request from the pipeline void popMe(const Http::StreamPointer &); /// Number of requests seen in this pipeline (so far). /// Includes incomplete transactions. uint32_t nrequests; private: /// requests parsed from the connection but not yet completed. std::list requests; }; #endif /* SQUID_SRC_PIPELINE_H */