src/ipc/Inquirer.h

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section 54    Interprocess Communication
   5  *
   6  */
   7
   8 #ifndef SQUID_IPC_INQUIRER_H
   9 #define SQUID_IPC_INQUIRER_H
  10
  11 #include "base/AsyncJobCalls.h"
  12 #include "base/AsyncJob.h"
  13 #include "ipc/forward.h"
  14 #include "ipc/Request.h"
  15 #include "ipc/Response.h"
  16 #include "ipc/StrandCoords.h"
  17 #include <map>
  18
  19
  20 namespace Ipc
  21 {
  22
  23 /// Coordinator's job that sends a cache manage request to each strand,
  24 /// aggregating individual strand responses and dumping the result if needed
  25 class Inquirer: public AsyncJob
  26 {
  27 public:
  28     Inquirer(Request::Pointer aRequest, const Ipc::StrandCoords& coords, double aTimeout);
  29     virtual ~Inquirer();
  30
  31     /// finds and calls the right Inquirer upon strand's response
  32     static void HandleRemoteAck(const Response& response);
  33
  34     /* has-to-be-public AsyncJob API */
  35     virtual void callException(const std::exception& e);
  36
  37 protected:
  38     /* AsyncJob API */
  39     virtual void start();
  40     virtual void swanSong();
  41     virtual bool doneAll() const;
  42     virtual const char *status() const;
  43
  44     /// inquire the next strand
  45     virtual void inquire();
  46     /// perform cleanup actions on completion of job
  47     virtual void cleanup();
  48     /// do specific exception handling
  49     virtual void handleException(const std::exception& e);
  50     /// send response to client
  51     virtual void sendResponse() = 0;
  52     /// perform aggregating of responses and returns true if need to continue
  53     virtual bool aggregate(Response::Pointer aResponse) = 0;
  54
  55 private:
  56     typedef UnaryMemFunT<Inquirer, Response::Pointer, Response::Pointer> HandleAckDialer;
  57
  58     void handleRemoteAck(Response::Pointer response);
  59
  60     static AsyncCall::Pointer DequeueRequest(unsigned int requestId);
  61
  62     static void RequestTimedOut(void* param);
  63     void requestTimedOut();
  64     void removeTimeoutEvent();
  65
  66 protected:
  67     Request::Pointer request; ///< cache manager request received from client
  68
  69     Ipc::StrandCoords strands; ///< all strands we want to query, in order
  70     Ipc::StrandCoords::const_iterator pos; ///< strand we should query now
  71
  72     const double timeout; ///< number of seconds to wait for strand response
  73
  74     /// maps request->id to Inquirer::handleRemoteAck callback
  75     typedef std::map<unsigned int, AsyncCall::Pointer> RequestsMap;
  76     static RequestsMap TheRequestsMap; ///< pending strand requests
  77
  78     static unsigned int LastRequestId; ///< last requestId used
  79
  80     CBDATA_CLASS2(Inquirer);
  81 };
  82
  83 } // namespace Ipc
  84
  85 #endif /* SQUID_IPC_INQUIRER_H */