src/base/RunnersRegistry.h

   1 #ifndef SQUID_BASE_RUNNERSREGISTRY_H
   2 #define SQUID_BASE_RUNNERSREGISTRY_H
   3
   4 /**
   5  * This API allows different modules to register with a well-known registry,
   6  * be activated by some central processor at some registry-specific time, and
   7  * be deactiveated by some central processor at some registry-specific time.
   8  *
   9  * For example, main.cc may activate registered I/O modules after parsing
  10  * squid.conf and deactivate them before exiting.
  11  *
  12  */
  13
  14 /// well-known registries (currently, deactivation is not performed for these)
  15 typedef enum {
  16     rrAfterConfig, ///< activated by main.cc after parsing squid.conf
  17     rrEnd ///< not a real registry, just a label to mark the end of enum
  18 } RunnerRegistry;
  19
  20 /// a runnable registrant API
  21 class RegisteredRunner {
  22 public:
  23     // called when this runner's registry is deactivated
  24     virtual ~RegisteredRunner() {}
  25
  26     // called when this runner's registry is activated
  27     virtual void run(const RunnerRegistry &r) = 0;
  28 };
  29
  30
  31 /// registers a given runner with the given registry and returns registry count
  32 int RegisterRunner(const RunnerRegistry &registry, RegisteredRunner *rr);
  33
  34 /// calls run() methods of all runners in the given registry
  35 int ActivateRegistered(const RunnerRegistry &registry);
  36 /// deletes all runners in the given registry
  37 void DeactivateRegistered(const RunnerRegistry &registry);
  38
  39
  40 /// convenience function to "use" an otherwise unreferenced static variable
  41 bool UseThisStatic(const void *);
  42
  43 /// convenience macro: register one RegisteredRunner kid as early as possible
  44 #define RunnerRegistrationEntry(Registry, Who) \
  45     static const bool Who ## _RegisteredWith_ ## Registry = \
  46         RegisterRunner(Registry, new Who) > 0 && \
  47         UseThisStatic(& Who ## _RegisteredWith_ ## Registry);
  48
  49 #endif /* SQUID_BASE_RUNNERSREGISTRY_H */