src/ipc/Inquirer.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 54    Interprocess Communication */
  10
  11 #ifndef SQUID_IPC_INQUIRER_H
  12 #define SQUID_IPC_INQUIRER_H
  13
  14 #include "base/AsyncJob.h"
  15 #include "base/AsyncJobCalls.h"
  16 #include "ipc/forward.h"
  17 #include "ipc/Request.h"
  18 #include "ipc/Response.h"
  19 #include "ipc/StrandCoords.h"
  20 #include <map>
  21
  22 namespace Ipc
  23 {
  24
  25 /// Coordinator's job that sends a cache manage request to each strand,
  26 /// aggregating individual strand responses and dumping the result if needed
  27 class Inquirer: public AsyncJob
  28 {
  29     CBDATA_CLASS(Inquirer);
  30
  31 public:
  32     Inquirer(Request::Pointer aRequest, const Ipc::StrandCoords& coords, double aTimeout);
  33     virtual ~Inquirer();
  34
  35     /// finds and calls the right Inquirer upon strand's response
  36     static void HandleRemoteAck(const Response& response);
  37
  38     /* has-to-be-public AsyncJob API */
  39     virtual void callException(const std::exception& e);
  40
  41 protected:
  42     /* AsyncJob API */
  43     virtual void start();
  44     virtual void swanSong();
  45     virtual bool doneAll() const;
  46     virtual const char *status() const;
  47
  48     /// inquire the next strand
  49     virtual void inquire();
  50     /// perform cleanup actions on completion of job
  51     virtual void cleanup();
  52     /// do specific exception handling
  53     virtual void handleException(const std::exception& e);
  54     /// send response to client
  55     virtual void sendResponse() = 0;
  56     /// perform aggregating of responses and returns true if need to continue
  57     virtual bool aggregate(Response::Pointer aResponse) = 0;
  58
  59 private:
  60     typedef UnaryMemFunT<Inquirer, Response::Pointer, Response::Pointer> HandleAckDialer;
  61
  62     void handleRemoteAck(Response::Pointer response);
  63
  64     static AsyncCall::Pointer DequeueRequest(unsigned int requestId);
  65
  66     static void RequestTimedOut(void* param);
  67     void requestTimedOut();
  68     void removeTimeoutEvent();
  69
  70 protected:
  71     Request::Pointer request; ///< cache manager request received from client
  72
  73     Ipc::StrandCoords strands; ///< all strands we want to query, in order
  74     Ipc::StrandCoords::const_iterator pos; ///< strand we should query now
  75
  76     const double timeout; ///< number of seconds to wait for strand response
  77
  78     /// maps request->id to Inquirer::handleRemoteAck callback
  79     typedef std::map<unsigned int, AsyncCall::Pointer> RequestsMap;
  80     static RequestsMap TheRequestsMap; ///< pending strand requests
  81
  82     static unsigned int LastRequestId; ///< last requestId used
  83 };
  84
  85 } // namespace Ipc
  86
  87 #endif /* SQUID_IPC_INQUIRER_H */
  88