src/adaptation/icap/Launcher.h

   1 /*
   2  * Copyright (C) 1996-2017 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 #ifndef SQUID_ICAPLAUNCHER_H
  10 #define SQUID_ICAPLAUNCHER_H
  11
  12 #include "adaptation/icap/ServiceRep.h"
  13 #include "adaptation/Initiate.h"
  14 #include "adaptation/Initiator.h"
  15
  16 /*
  17  * The ICAP Launcher starts an ICAP transaction. If the transaction fails
  18  * due to what looks like a persistent connection race condition, the launcher
  19  * starts a new ICAP transaction using a freshly opened connection.
  20  *
  21  * ICAPLauncher and one or more ICAP transactions initiated by it form an
  22  * ICAP "query".
  23  *
  24  * An ICAP Initiator deals with the ICAP Launcher and not an individual ICAP
  25  * transaction because the latter may disappear and be replaced by another
  26  * transaction.
  27  *
  28  * Specific ICAP launchers implement the createXaction() method to create
  29  * REQMOD, RESPMOD, or OPTIONS transaction from initiator-supplied data.
  30  *
  31  * TODO: This class might be the right place to initiate ICAP ACL checks or
  32  * implement more sophisticated ICAP transaction handling like chaining of
  33  * ICAP transactions.
  34  */
  35
  36 namespace Adaptation
  37 {
  38 namespace Icap
  39 {
  40
  41 class Xaction;
  42 class XactAbortInfo;
  43
  44 // Note: Initiate must be the first parent for cbdata to work. We use
  45 // a temporary InitaitorHolder/toCbdata hacks and do not call cbdata
  46 // operations on the initiator directly.
  47 class Launcher: public Adaptation::Initiate, public Adaptation::Initiator
  48 {
  49 public:
  50     Launcher(const char *aTypeName, Adaptation::ServicePointer &aService);
  51     virtual ~Launcher();
  52
  53     // Adaptation::Initiate: asynchronous communication with the initiator
  54     void noteInitiatorAborted();
  55
  56     // Adaptation::Initiator: asynchronous communication with the current transaction
  57     virtual void noteAdaptationAnswer(const Answer &answer);
  58     virtual void noteXactAbort(XactAbortInfo info);
  59
  60 private:
  61     bool canRetry(XactAbortInfo &info) const; //< true if can retry in the case of persistent connection failures
  62     bool canRepeat(XactAbortInfo &info) const; //< true if can repeat in the case of no or unsatisfactory response
  63
  64 protected:
  65     // Adaptation::Initiate API implementation
  66     virtual void start();
  67     virtual bool doneAll() const;
  68     virtual void swanSong();
  69
  70     // creates the right ICAP transaction using stored configuration params
  71     virtual Xaction *createXaction() = 0;
  72
  73     void launchXaction(const char *xkind);
  74
  75     Adaptation::ServicePointer theService; ///< ICAP service for all launches
  76     CbcPointer<Initiate> theXaction; ///< current ICAP transaction
  77     int theLaunches; // the number of transaction launches
  78 };
  79
  80 /// helper class to pass information about aborted ICAP requests to
  81 /// the Adaptation::Icap::Launcher class
  82 class XactAbortInfo
  83 {
  84 public:
  85     XactAbortInfo(HttpRequest *anIcapRequest, HttpReply *anIcapReply,
  86                   bool beRetriable, bool beRepeatable);
  87     XactAbortInfo(const XactAbortInfo &);
  88     ~XactAbortInfo();
  89
  90     std::ostream &print(std::ostream &os) const {
  91         return os << isRetriable << ',' << isRepeatable;
  92     }
  93
  94     HttpRequest *icapRequest;
  95     HttpReply *icapReply;
  96     bool isRetriable;
  97     bool isRepeatable;
  98
  99 private:
 100     XactAbortInfo &operator =(const XactAbortInfo &); // undefined
 101 };
 102
 103 inline
 104 std::ostream &
 105 operator <<(std::ostream &os, const XactAbortInfo &xai)
 106 {
 107     return xai.print(os);
 108 }
 109
 110 } // namespace Icap
 111 } // namespace Adaptation
 112
 113 #endif /* SQUID_ICAPLAUNCHER_H */
 114