AsyncCall.cc

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#include "squid.h"
#include "base/AsyncCall.h"
#include "base/AsyncCallQueue.h"
#include "base/CodeContext.h"
#include "cbdata.h"
#include "debug/Stream.h"
#include <ostream>
 
InstanceIdDefinitions(AsyncCall, "call");
 
/* AsyncCall */
 
AsyncCall::AsyncCall(int aDebugSection, int aDebugLevel, const char *aName):
    name(aName),
    codeContext(CodeContext::Current()),
    debugSection(aDebugSection),
    debugLevel(aDebugLevel),
    theNext(nullptr),
    isCanceled(nullptr)
{
    debugs(debugSection, debugLevel, "The AsyncCall " << name << " constructed, this=" << this <<
           " [" << id << ']');
}
 
AsyncCall::~AsyncCall()
{
    assert(!theNext); // AsyncCallQueue must clean
}
 
void
AsyncCall::make()
{
    debugs(debugSection, debugLevel, "make call " << name <<
           " [" << id << ']');
    if (canFire()) {
        fire();
        return;
    }
 
    if (!isCanceled) // we did not cancel() when returning false from canFire()
        isCanceled = "unknown reason";
 
    debugs(debugSection, debugLevel, "will not call " << name <<
           " [" << id << ']' << " because of " << isCanceled);
}
 
bool
AsyncCall::cancel(const char *reason)
{
    debugs(debugSection, debugLevel, "will not call " << name <<
           " [" << id << "] " << (isCanceled ? "also " : "") <<
           "because " << reason);
 
    isCanceled = reason;
    return false;
}
 
bool
AsyncCall::canFire()
{
    return !isCanceled;
}
 
// TODO: make this method const by providing a const getDialer()
void
AsyncCall::print(std::ostream &os)
{
    os << name;
    if (const CallDialer *dialer = getDialer())
        dialer->print(os);
    else
        os << "(?" << this << "?)";
}
 
void
AsyncCall::dequeue(AsyncCall::Pointer &head, AsyncCall::Pointer &prev)
{
    if (prev != nullptr)
        prev->setNext(Next());
    else
        head = Next();
    setNext(nullptr);
}
 
bool
ScheduleCall(const char *fileName, int fileLine, const AsyncCall::Pointer &call)
{
    debugs(call->debugSection, call->debugLevel, fileName << "(" << fileLine <<
           ") will call " << *call << " [" << call->id << ']' );
 
    // Support callback creators that did not get their context from service A,
    // but the current caller (service B) got that context from another source.
    if (!call->codeContext)
        call->codeContext = CodeContext::Current();
 
    AsyncCallQueue::Instance().schedule(call);
    return true;
}