[4937] | 1 | /* -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ |
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| 2 | /* |
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| 3 | * Copyright (C) 2004-2012 HUBzero Foundation, LLC |
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| 4 | * |
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| 5 | * Author: George A. Howlett <gah@purdue.edu> |
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| 6 | */ |
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| 7 | #ifndef NV_RESPONSE_QUEUE_H |
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| 8 | #define NV_RESPONSE_QUEUE_H |
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| 9 | |
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| 10 | #include <pthread.h> |
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| 11 | #include <semaphore.h> |
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| 12 | #include <cstdlib> |
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| 13 | #include <cstring> |
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| 14 | #include <list> |
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| 15 | |
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| 16 | namespace nv { |
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| 17 | |
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| 18 | /** |
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| 19 | * \brief Holds data for a response to be sent to client |
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| 20 | */ |
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| 21 | class Response |
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| 22 | { |
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| 23 | public: |
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| 24 | enum AllocationType { |
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| 25 | STATIC, |
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| 26 | DYNAMIC, |
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| 27 | VOLATILE |
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| 28 | }; |
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| 29 | enum ResponseType { |
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| 30 | IMAGE, /**< Image to be displayed. */ |
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| 31 | LEGEND, /**< Legend to be displayed. */ |
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| 32 | DATA, /**< Any other type of non-error message. */ |
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| 33 | ERROR, /**< Error message. */ |
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| 34 | OK /**< Ack for client when no render required */ |
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| 35 | }; |
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| 36 | |
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| 37 | Response(ResponseType type) : |
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| 38 | _mesg(NULL), |
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| 39 | _length(0), |
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| 40 | _type(type) |
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| 41 | { |
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| 42 | } |
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| 43 | |
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| 44 | virtual ~Response() |
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| 45 | { |
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| 46 | if ((_length > 0) && (_mesg != NULL) && (_allocType == DYNAMIC)) { |
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| 47 | free(_mesg); |
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| 48 | } |
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| 49 | } |
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| 50 | |
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| 51 | /// Get the ResponseType |
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| 52 | ResponseType type() |
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| 53 | { |
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| 54 | return _type; |
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| 55 | } |
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| 56 | |
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| 57 | /// Get the Response data |
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| 58 | unsigned char *message() |
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| 59 | { |
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| 60 | return _mesg; |
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| 61 | } |
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| 62 | |
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| 63 | /// Get the number of bytes in the Response data |
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| 64 | size_t length() |
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| 65 | { |
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| 66 | return _length; |
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| 67 | } |
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| 68 | |
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| 69 | /// Set the message/data making up the Response |
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| 70 | /** |
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| 71 | * If the AllocationType is DYNAMIC, the message data will be free()d |
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| 72 | * by the destructor. If the AllocationType is VOLATILE, a copy of |
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| 73 | * the message data will be made. |
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| 74 | * |
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| 75 | * \param[in] mesg The Response data, can be a command and/or binary data |
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| 76 | * \param[in] length The number of bytes in mesg |
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| 77 | * \param[in] type Specify how the memory was allocated for mesg |
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| 78 | */ |
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| 79 | void setMessage(unsigned char *mesg, size_t length, AllocationType type) |
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| 80 | { |
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| 81 | if (type == VOLATILE) { |
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| 82 | _length = length; |
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| 83 | _mesg = (unsigned char *)malloc(length); |
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| 84 | memcpy(_mesg, mesg, length); |
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| 85 | _allocType = DYNAMIC; |
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| 86 | } else { |
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| 87 | _length = length; |
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| 88 | _mesg = mesg; |
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| 89 | _allocType = type; |
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| 90 | } |
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| 91 | } |
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| 92 | |
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| 93 | private: |
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| 94 | /** |
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| 95 | * (Malloc-ed by caller, freed by destructor) |
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| 96 | * Contains the message/bytes to be sent to the client. */ |
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| 97 | unsigned char *_mesg; |
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| 98 | size_t _length; /**< # of bytes in the above message. */ |
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| 99 | ResponseType _type; |
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| 100 | AllocationType _allocType; |
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| 101 | }; |
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| 102 | |
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| 103 | /** |
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| 104 | * \brief Queue to hold pending Responses to be sent to the client |
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| 105 | * |
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| 106 | * A semaphore and mutex are used to control access to the |
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| 107 | * queue by a reader and writer thread |
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| 108 | */ |
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| 109 | class ResponseQueue |
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| 110 | { |
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| 111 | public: |
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| 112 | ResponseQueue(); |
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| 113 | |
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| 114 | virtual ~ResponseQueue(); |
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| 115 | |
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| 116 | /// Add a response to the end of the queue |
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| 117 | void enqueue(Response *response); |
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| 118 | |
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| 119 | /// Remove a response from the front of the queue |
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| 120 | Response *dequeue(); |
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| 121 | |
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| 122 | private: |
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| 123 | pthread_mutex_t _idle; |
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| 124 | sem_t _ready; /**< Semaphore indicating that a response has been queued. */ |
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| 125 | std::list<Response *> _list; |
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| 126 | }; |
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| 127 | |
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| 128 | } |
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| 129 | |
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| 130 | #endif |
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