src/ipc/Inquirer.h

   1 /*
   2  * Copyright (C) 1996-2020 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 "base/forward.h"
  17 #include "ipc/forward.h"
  18 #include "ipc/Request.h"
  19 #include "ipc/Response.h"
  20 #include "ipc/StrandCoords.h"
  21 #include <map>
  22
  23 namespace Ipc
  24 {
  25
  26 /// Coordinator's job that sends a cache manage request to each strand,
  27 /// aggregating individual strand responses and dumping the result if needed
  28 class Inquirer: public AsyncJob
  29 {
  30     CBDATA_CLASS(Inquirer);
  31
  32 public:
  33     Inquirer(Request::Pointer aRequest, const Ipc::StrandCoords& coords, double aTimeout);
  34     virtual ~Inquirer();
  35
  36     /// finds and calls the right Inquirer upon strand's response
  37     static void HandleRemoteAck(const Response& response);
  38
  39     /* has-to-be-public AsyncJob API */
  40     virtual void callException(const std::exception& e);
  41
  42     CodeContextPointer codeContext;
  43
  44 protected:
  45     /* AsyncJob API */
  46     virtual void start();
  47     virtual void swanSong();
  48     virtual bool doneAll() const;
  49     virtual const char *status() const;
  50
  51     /// inquire the next strand
  52     virtual void inquire();
  53     /// perform cleanup actions on completion of job
  54     virtual void cleanup();
  55     /// do specific exception handling
  56     virtual void handleException(const std::exception& e);
  57     /// send response to client
  58     virtual void sendResponse() = 0;
  59     /// perform aggregating of responses and returns true if need to continue
  60     virtual bool aggregate(Response::Pointer aResponse) = 0;
  61
  62 private:
  63     typedef UnaryMemFunT<Inquirer, Response::Pointer, Response::Pointer> HandleAckDialer;
  64
  65     void handleRemoteAck(Response::Pointer response);
  66
  67     static AsyncCall::Pointer DequeueRequest(RequestId::Index);
  68
  69     static void RequestTimedOut(void* param);
  70     void requestTimedOut();
  71     void removeTimeoutEvent();
  72
  73 protected:
  74     Request::Pointer request; ///< cache manager request received from client
  75
  76     Ipc::StrandCoords strands; ///< all strands we want to query, in order
  77     Ipc::StrandCoords::const_iterator pos; ///< strand we should query now
  78
  79     const double timeout; ///< number of seconds to wait for strand response
  80
  81     /// maps request->id to Inquirer::handleRemoteAck callback
  82     typedef std::map<RequestId::Index, AsyncCall::Pointer> RequestsMap;
  83     static RequestsMap TheRequestsMap; ///< pending strand requests
  84
  85     static RequestId::Index LastRequestId; ///< last requestId used
  86 };
  87
  88 } // namespace Ipc
  89
  90 #endif /* SQUID_IPC_INQUIRER_H */
  91