src/base/AsyncCall.cc

   1 /*
   2  * Copyright (C) 1996-2019 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 #include "squid.h"
  10 #include "base/AsyncCall.h"
  11 #include "base/AsyncCallQueue.h"
  12 #include "base/CodeContext.h"
  13 #include "cbdata.h"
  14 #include "Debug.h"
  15 #include <ostream>
  16
  17 InstanceIdDefinitions(AsyncCall, "call");
  18
  19 /* AsyncCall */
  20
  21 AsyncCall::AsyncCall(int aDebugSection, int aDebugLevel, const char *aName):
  22     name(aName),
  23     codeContext(CodeContext::Current()),
  24     debugSection(aDebugSection),
  25     debugLevel(aDebugLevel),
  26     theNext(nullptr),
  27     isCanceled(nullptr)
  28 {
  29     debugs(debugSection, debugLevel, "The AsyncCall " << name << " constructed, this=" << this <<
  30            " [" << id << ']');
  31 }
  32
  33 AsyncCall::~AsyncCall()
  34 {
  35     assert(!theNext); // AsyncCallQueue must clean
  36 }
  37
  38 void
  39 AsyncCall::make()
  40 {
  41     debugs(debugSection, debugLevel, HERE << "make call " << name <<
  42            " [" << id << ']');
  43     if (canFire()) {
  44         fire();
  45         return;
  46     }
  47
  48     if (!isCanceled) // we did not cancel() when returning false from canFire()
  49         isCanceled = "unknown reason";
  50
  51     debugs(debugSection, debugLevel, HERE << "will not call " << name <<
  52            " [" << id << ']' << " because of " << isCanceled);
  53 }
  54
  55 bool
  56 AsyncCall::cancel(const char *reason)
  57 {
  58     debugs(debugSection, debugLevel, HERE << "will not call " << name <<
  59            " [" << id << "] " << (isCanceled ? "also " : "") <<
  60            "because " << reason);
  61
  62     isCanceled = reason;
  63     return false;
  64 }
  65
  66 bool
  67 AsyncCall::canFire()
  68 {
  69     return !isCanceled;
  70 }
  71
  72 /// \todo make this method const by providing a const getDialer()
  73 void
  74 AsyncCall::print(std::ostream &os)
  75 {
  76     os << name;
  77     if (const CallDialer *dialer = getDialer())
  78         dialer->print(os);
  79     else
  80         os << "(?" << this << "?)";
  81 }
  82
  83 void
  84 AsyncCall::dequeue(AsyncCall::Pointer &head, AsyncCall::Pointer &prev)
  85 {
  86     if (prev != NULL)
  87         prev->setNext(Next());
  88     else
  89         head = Next();
  90     setNext(NULL);
  91 }
  92
  93 bool
  94 ScheduleCall(const char *fileName, int fileLine, AsyncCall::Pointer &call)
  95 {
  96     debugs(call->debugSection, call->debugLevel, fileName << "(" << fileLine <<
  97            ") will call " << *call << " [" << call->id << ']' );
  98
  99     // Support callback creators that did not get their context from service A,
 100     // but the current caller (service B) got that context from another source.
 101     if (!call->codeContext)
 102         call->codeContext = CodeContext::Current();
 103
 104     AsyncCallQueue::Instance().schedule(call);
 105     return true;
 106 }
 107