src/base/AsyncJob.cc

   1 /*
   2  * DEBUG: section 93    ICAP (RFC 3507) Client
   3  */
   4
   5 #include "squid.h"
   6 #include "base/AsyncCall.h"
   7 #include "base/AsyncJob.h"
   8 #include "base/AsyncJobCalls.h"
   9 #include "base/TextException.h"
  10 #include "cbdata.h"
  11 #include "MemBuf.h"
  12
  13 #include <ostream>
  14
  15 InstanceIdDefinitions(AsyncJob, "job");
  16
  17 AsyncJob::Pointer AsyncJob::Start(AsyncJob *j)
  18 {
  19     AsyncJob::Pointer job(j);
  20     CallJobHere(93, 5, job, AsyncJob, start);
  21     return job;
  22 }
  23
  24 AsyncJob::AsyncJob(const char *aTypeName): typeName(aTypeName), inCall(NULL)
  25 {
  26     debugs(93,5, "AsyncJob constructed, this=" << this <<
  27            " type=" << typeName << " [" << id << ']');
  28 }
  29
  30 AsyncJob::~AsyncJob()
  31 {
  32     debugs(93,5, "AsyncJob destructed, this=" << this <<
  33            " type=" << typeName << " [" << id << ']');
  34 }
  35
  36 void AsyncJob::start()
  37 {
  38 }
  39
  40 // XXX: temporary code to replace calls to "delete this" in jobs-in-transition.
  41 // Will be replaced with calls to mustStop() when transition is complete.
  42 void AsyncJob::deleteThis(const char *aReason)
  43 {
  44     Must(aReason);
  45     stopReason = aReason;
  46     if (inCall != NULL) {
  47         // if we are in-call, then the call wrapper will delete us
  48         debugs(93, 4, typeName << " will NOT delete in-call job, reason: " << stopReason);
  49         return;
  50     }
  51
  52     // there is no call wrapper waiting for our return, so we fake it
  53     debugs(93, 5, typeName << " will delete this, reason: " << stopReason);
  54     CbcPointer<AsyncJob> self(this);
  55     AsyncCall::Pointer fakeCall = asyncCall(93,4, "FAKE-deleteThis",
  56                                             JobMemFun(self, &AsyncJob::deleteThis, aReason));
  57     inCall = fakeCall;
  58     callEnd();
  59 //    delete fakeCall;
  60 }
  61
  62 void AsyncJob::mustStop(const char *aReason)
  63 {
  64     // XXX: temporary code to catch cases where mustStop is called outside
  65     // of an async call context. Will be removed when that becomes impossible.
  66     // Until then, this will cause memory leaks and possibly other problems.
  67     if (!inCall) {
  68         stopReason = aReason;
  69         debugs(93, 5, typeName << " will STALL, reason: " << stopReason);
  70         return;
  71     }
  72
  73     Must(inCall != NULL); // otherwise nobody will delete us if we are done()
  74     Must(aReason);
  75     if (!stopReason) {
  76         stopReason = aReason;
  77         debugs(93, 5, typeName << " will stop, reason: " << stopReason);
  78     } else {
  79         debugs(93, 5, typeName << " will stop, another reason: " << aReason);
  80     }
  81 }
  82
  83 bool AsyncJob::done() const
  84 {
  85     // stopReason, set in mustStop(), overwrites all other conditions
  86     return stopReason != NULL || doneAll();
  87 }
  88
  89 bool AsyncJob::doneAll() const
  90 {
  91     return true; // so that it is safe for kids to use
  92 }
  93
  94 bool AsyncJob::canBeCalled(AsyncCall &call) const
  95 {
  96     if (inCall != NULL) {
  97         // This may happen when we have bugs or some module is not calling
  98         // us asynchronously (comm used to do that).
  99         debugs(93, 5, HERE << inCall << " is in progress; " <<
 100                call << " canot reenter the job.");
 101         return call.cancel("reentrant job call");
 102     }
 103
 104     return true;
 105 }
 106
 107 void AsyncJob::callStart(AsyncCall &call)
 108 {
 109     // we must be called asynchronously and hence, the caller must lock us
 110     Must(cbdataReferenceValid(toCbdata()));
 111
 112     Must(!inCall); // see AsyncJob::canBeCalled
 113
 114     inCall = &call; // XXX: ugly, but safe if callStart/callEnd,Ex are paired
 115     debugs(inCall->debugSection, inCall->debugLevel,
 116            typeName << " status in:" << status());
 117 }
 118
 119 void AsyncJob::callException(const std::exception &e)
 120 {
 121     // we must be called asynchronously and hence, the caller must lock us
 122     Must(cbdataReferenceValid(toCbdata()));
 123
 124     mustStop("exception");
 125 }
 126
 127 void AsyncJob::callEnd()
 128 {
 129     if (done()) {
 130         debugs(93, 5, *inCall << " ends job" << status());
 131
 132         AsyncCall::Pointer inCallSaved = inCall;
 133         void *thisSaved = this;
 134
 135         swanSong();
 136
 137         delete this; // this is the only place where the object is deleted
 138
 139         // careful: this object does not exist any more
 140         debugs(93, 6, HERE << *inCallSaved << " ended " << thisSaved);
 141         return;
 142     }
 143
 144     debugs(inCall->debugSection, inCall->debugLevel,
 145            typeName << " status out:" << status());
 146     inCall = NULL;
 147 }
 148
 149 // returns a temporary string depicting transaction status, for debugging
 150 const char *AsyncJob::status() const
 151 {
 152     static MemBuf buf;
 153     buf.reset();
 154
 155     buf.append(" [", 2);
 156     if (stopReason != NULL) {
 157         buf.Printf("Stopped, reason:");
 158         buf.Printf("%s",stopReason);
 159     }
 160     buf.Printf(" %s%u]", id.Prefix, id.value);
 161     buf.terminate();
 162
 163     return buf.content();
 164 }
 165