src/base/AsyncCallQueue.cc

   1
   2 /*
   3  * DEBUG: section 41    Event Processing
   4  *
   5  */
   6
   7 #include "squid.h"
   8 #include "base/AsyncCall.h"
   9 #include "base/AsyncCallQueue.h"
  10 #include "Debug.h"
  11
  12 AsyncCallQueue *AsyncCallQueue::TheInstance = 0;
  13
  14 AsyncCallQueue::AsyncCallQueue(): theHead(NULL), theTail(NULL)
  15 {
  16 }
  17
  18 void AsyncCallQueue::schedule(AsyncCall::Pointer &call)
  19 {
  20     assert(call != NULL);
  21     assert(!call->theNext);
  22     if (theHead != NULL) { // append
  23         assert(!theTail->theNext);
  24         theTail->theNext = call;
  25         theTail = call;
  26     } else { // create queue from cratch
  27         theHead = theTail = call;
  28     }
  29 }
  30
  31 // Fire all scheduled calls; returns true if at least one call was fired.
  32 // The calls may be added while the current call is in progress.
  33 bool
  34 AsyncCallQueue::fire()
  35 {
  36     const bool made = theHead != NULL;
  37     while (theHead != NULL)
  38         fireNext();
  39     return made;
  40 }
  41
  42 void
  43 AsyncCallQueue::fireNext()
  44 {
  45     AsyncCall::Pointer call = theHead;
  46     theHead = call->theNext;
  47     call->theNext = NULL;
  48     if (theTail == call)
  49         theTail = NULL;
  50
  51     debugs(call->debugSection, call->debugLevel, "entering " << *call);
  52     call->make();
  53     debugs(call->debugSection, call->debugLevel, "leaving " << *call);
  54 }
  55
  56 AsyncCallQueue &
  57 AsyncCallQueue::Instance()
  58 {
  59     // TODO: how to remove this frequent check while supporting early calls?
  60     if (!TheInstance)
  61         TheInstance = new AsyncCallQueue();
  62
  63     return *TheInstance;
  64 }
  65