/** * @file lliopipe.h * @author Phoenix * @date 2004-11-18 * @brief Declaration of base IO class * * $LicenseInfo:firstyear=2004&license=viewerlgpl$ * Second Life Viewer Source Code * Copyright (C) 2010, Linden Research, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; * version 2.1 of the License only. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA * $/LicenseInfo$ */ #ifndef LL_LLIOPIPE_H #define LL_LLIOPIPE_H #include <boost/intrusive_ptr.hpp> #include "llwin32headers.h" #include "apr_poll.h" #include "llsd.h" class LLIOPipe; class LLPumpIO; class LLBufferArray; class LLChannelDescriptors; // Debugging schmutz for deadlocks //#define LL_DEBUG_PUMPS #ifdef LL_DEBUG_PUMPS void pump_debug(const char *file, S32 line); #define PUMP_DEBUG pump_debug(__FILE__, __LINE__); #define END_PUMP_DEBUG pump_debug("none", 0); #else /* LL_DEBUG_PUMPS */ #define PUMP_DEBUG #define END_PUMP_DEBUG #endif /** * intrusive pointer support */ void intrusive_ptr_add_ref(LLIOPipe* p); void intrusive_ptr_release(LLIOPipe* p); /** * @class LLIOPipe * @brief This class is an abstract base class for data processing units * @see LLPumpIO * * The LLIOPipe is a base class for implementing the basic non-blocking * processing of data subsystem in our system. * * Implementations of this class should behave like a stateful or * stateless signal processor. Each call to <code>process()</code> * hands the pipe implementation a buffer and a set of channels in the * buffer to process, and the pipe returns the status of the * operation. This is an abstract base class and developer created * concrete implementations provide block or stream based processing * of data to implement a particular protocol. */ class LLIOPipe { public: /** * @brief I have decided that IO objects should have a reference * count. In general, you can pass bald LLIOPipe pointers around * as you need, but if you need to maintain a reference to one, * you need to hold a ptr_t. */ typedef boost::intrusive_ptr<LLIOPipe> ptr_t; /** * @brief Scattered memory container. */ typedef std::shared_ptr<LLBufferArray> buffer_ptr_t; /** * @brief Enumeration for IO return codes * * A status code a positive integer value is considered a success, * but may indicate special handling for future calls, for * example, issuing a STATUS_STOP to an LLIOSocketReader instance * will tell the instance to stop reading the socket. A status * code with a negative value means that a problem has been * encountered which will require further action on the caller or * a developer to correct. Some mechanisms, such as the LLPumpIO * may depend on this definition of success and failure. */ enum EStatus { // Processing occurred normally, future calls will be accepted. STATUS_OK = 0, // Processing occured normally, but stop unsolicited calls to // process. STATUS_STOP = 1, // This pipe is done with the processing. Future calls to // process will be accepted as long as new data is available. STATUS_DONE = 2, // This pipe is requesting that it become the head in a process. STATUS_BREAK = 3, // This pipe is requesting that it become the head in a process. STATUS_NEED_PROCESS = 4, // Keep track of the highest number of success codes here. STATUS_SUCCESS_COUNT = 5, // A generic error code. STATUS_ERROR = -1, // This method has not yet been implemented. This usually // indicates the programmer working on the pipe is not yet // done. STATUS_NOT_IMPLEMENTED = -2, // This indicates that a pipe precondition was not met. For // example, many pipes require an element to appear after them // in a chain (ie, mNext is not null) and will return this in // response to method calls. To recover from this, it will // require the caller to adjust the pipe state or may require // a dev to adjust the code to satisfy the preconditions. STATUS_PRECONDITION_NOT_MET = -3, // This means we could not connect to a remote host. STATUS_NO_CONNECTION = -4, // The connection was lost. STATUS_LOST_CONNECTION = -5, // The totoal process time has exceeded the timeout. STATUS_EXPIRED = -6, // Keep track of the count of codes here. STATUS_ERROR_COUNT = 6, }; /** * @brief Helper function to check status. * * When writing code to check status codes, if you do not * specifically check a particular value, use this method for * checking an error condition. * @param status The status to check. * @return Returns true if the code indicates an error occurred. */ inline static bool isError(EStatus status) { return ((S32)status < 0); } /** * @brief Helper function to check status. * * When writing code to check status codes, if you do not * specifically check a particular value, use this method for * checking an error condition. * @param status The status to check. * @return Returns true if the code indicates no error was generated. */ inline static bool isSuccess(EStatus status) { return ((S32)status >= 0); } /** * @brief Helper function to turn status into a string. * * @param status The status to check. * @return Returns the name of the status code or empty string on failure. */ static std::string lookupStatusString(EStatus status); /** * @brief Process the data in buffer. * * @param data The data processed * @param eos True if this function call is the last because end of stream. * @param pump The pump which is calling process. May be NULL. * @param context Shared meta-data for the process. * @return Returns a status code from the operation. */ EStatus process( const LLChannelDescriptors& channels, buffer_ptr_t& buffer, bool& eos, LLSD& context, LLPumpIO* pump); /** * @brief Give this pipe a chance to handle a generated error * * If this pipe is in a chain being processed by a pump, and one * of the pipes generates an error, the pump will rewind through * the chain to see if any of the links can handle the error. For * example, if a connection is refused in a socket connection, the * socket client can try to find a new destination host. Return an * error code if this pipe does not handle the error passed in. * @param status The status code for the error * @param pump The pump which was calling process before the error * was generated. * @return Returns a status code from the operation. Returns an * error code if the error passed in was not handled. Returns * STATUS_OK to indicate the error has been handled. */ virtual EStatus handleError(EStatus status, LLPumpIO* pump); /** * @brief Base Destructor - do not call <code>delete</code> directly. */ virtual ~LLIOPipe(); virtual bool isValid() ; protected: /** * @brief Base Constructor. */ LLIOPipe(); /** * @brief Process the data in buffer */ virtual EStatus process_impl( const LLChannelDescriptors& channels, buffer_ptr_t& buffer, bool& eos, LLSD& context, LLPumpIO* pump) = 0; private: friend void intrusive_ptr_add_ref(LLIOPipe* p); friend void intrusive_ptr_release(LLIOPipe* p); U32 mReferenceCount; }; inline void intrusive_ptr_add_ref(LLIOPipe* p) { ++p->mReferenceCount; } inline void intrusive_ptr_release(LLIOPipe* p) { if(p && 0 == --p->mReferenceCount) { delete p; } } #endif // LL_LLIOPIPE_H