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gml_ServiceDiscovery.h Go to the documentation of this file. /** @file gml_ServiceDiscovery.h * * Object interface to the DNSServiceDiscovery API. * * Note that registered callbacks aren't passed result data; * they should instead fetch it using the GetAnswer() methods of the * various classes. * * Classes defined: gml_TSDBrowser, gml_TSDRegistrator, gml_TSDResolver. * * Copyright (c) 2004 CLIPS-IMAG * * See the file "gml_LicenseTerms.txt" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * */ #ifndef __GML_SERVICE_DISCOVERY__ #define __GML_SERVICE_DISCOVERY__ #include <assert.h> #include <stdint.h> #include "gml/base/gml_Array.h" #include "gml/base/gml_Callback.h" #include "gml/base/gml_Queue.h" #include "gml/base/gml_Thread.h" // as per DNS-SD draft: #define GML_MAX_TXT_LENGTH 8800 #define GML_MAX_NAME_LENGTH 62 #define GML_MAX_HOST_LENGTH 256 #define GML_MAX_TYPE_LENGTH 62 // forward declaration of dns-sd structures typedef struct _DNSServiceRef_t *DNSServiceRef; typedef uint32_t DNSServiceFlags; typedef int32_t DNSServiceErrorType; /////////////////////////////////////////////////////////////////////////////// #pragma mark - #pragma mark General tools for DNS-SD connections /// gml_TSDMetaDataEntry -- /// /// A field of a TXT record. struct gml_TSDMetaDataEntry { gml_TSDMetaDataEntry () { gml_Zero (fKey); gml_Zero (fValue); fHasValue = false; } gml_TSDMetaDataEntry (char* key, char* value = (char*)NULL) { assert (strlen (key) < 256); strncpy (fKey, key, 256); if (value != (char*)NULL) { strncpy (fValue, value, 256); fHasValue = true; } else { fHasValue = false; } } char fKey [256]; ///< the field name or key char fValue [256]; ///< the corresponding value (can be empty) bool fHasValue; ///< wether the field has a value (or is only a key) }; /// gml_TSDMetaData -- /// /// Represent a TXT record as an array of entries. class gml_TSDMetaData : public gml_TArray<gml_TSDMetaDataEntry> { public: /// Init -- /// /// Setup a new TXT record. gml_TError Init (); /// Export -- /// /// Convert the metadata array into a pascal-style array of strings. void Export (unsigned &bytes, unsigned char* record); /// Import -- /// /// Flush the array and fill it with the supplied pascal-style array. gml_TError Import (unsigned bytes, unsigned char const* record); }; /// gml_TSDConnection -- /// /// Encapsulate a connection to the DNS Service Discovery daemon. /// This class cannot be instantiated. class gml_TSDConnection { public: /// Delete -- /// /// Terminate a SD connection, given it's ID number. static void Delete (int id) ; /// Dispose -- /// /// Terminate the SD connection. virtual void Dispose (); virtual ~gml_TSDConnection () {} /// Identity -- /// /// Return the ID number of this SD connection. virtual int Identity () { return fInstanceID; } protected: /// Init -- /// /// Setup private data. gml_TError Init (); /// Start -- /// /// Register this SD connection. /// Setup a watcher thread so that <callback> is called with /// parameter <userData> whenever a SD event occurs on <sdRef>. gml_TError Start (DNSServiceRef sdRef, gml_TCallback callback, gml_TPointer userData); /// Notify -- /// /// Execute the registered callback, with parameter <err>. virtual void Notify (gml_TError err = gml_cNoError); private: /// SocketNotifierGeneric -- /// /// Generic entry point for SD connection watcher threads. static void SocketNotifierGeneric (gml_TThreadId tid, void* clientdata); /// SocketNotifier -- /// /// Entry point for SD connection watcher threads. void SocketNotifier (); private: DNSServiceRef fSdRef; ///< connection to mDNSd int fInstanceID; ///< unique identifier for a SD connection gml_TCallback fCallback; ///< registered callback function gml_TPointer fUserData; ///< registered callback argument int fSelectThreadRun; ///< flag controlling the notification thread gml_TThreadId fSelectThread; ///< identifier of the notification thread static int fInstanceCounter; ///< total number of SD connections since startup static gml_TList* fInstances; ///< current list of SD connections }; /////////////////////////////////////////////////////////////////////////////// #pragma mark - #pragma mark Service browsing /// gml_TSDBrowser -- /// /// Perform discovery of available network services. class gml_TSDBrowser : public gml_TSDConnection { public: /// Init -- /// /// Setup a new browser. gml_TError Init ( gml_TCallback callback, ///< function to be called on browser events gml_TPointer userData, ///< parameter passed to <callback> const char* regType, ///< service type browsed for, e.g. "_http._tcp" UInt32 interfaceIndex = (UInt32)0, ///< number of browsing inferface, -1 for local search only const char* nameGlob = (char*)NULL ///< glob filtering pattern for service names ); /// Dispose -- /// /// Stop browsing. void Dispose (); /// Event -- /// /// Representation of browser events. struct Event { gml_TBoolean fAdded; ///< true iff the service appeared char fName [GML_MAX_NAME_LENGTH+1]; ///< service (unique) name char fRegType [GML_MAX_NAME_LENGTH+1]; ///< type of discovered service char fDomain [GML_MAX_HOST_LENGTH+1]; ///< service domain }; /// GetAnswer -- /// /// Return in <event> the oldest available browsing event, and remove it /// from the event queue; if no event is available, return /// <gml_TQueue_Base::sErrorQueueEmpty>. gml_TError GetAnswer (Event &event); private: /// HandlerEvent -- /// /// Called by <DNSServiceProcessResult> on incoming events. /// @see <gml_TSDConnection::SocketNotifier>. static void HandlerEvent ( DNSServiceRef /*sdRef*/, DNSServiceFlags flags, uint32_t /*interfaceIndex*/, DNSServiceErrorType errorCode, const char *serviceName, const char *regType, const char *eventDomain, void *context ); private: gml_TQueue<Event>* fEvents; ///< unprocessed browsing events char fNameGlob [GML_MAX_NAME_LENGTH+1]; ///< filtering glob pattern }; /////////////////////////////////////////////////////////////////////////////// #pragma mark - #pragma mark Service registration /// gml_TSDRegistrator -- /// /// Register a discoverable service. class gml_TSDRegistrator: public gml_TSDConnection { public: /// Init -- /// /// Setup a new registrator. gml_TError Init ( gml_TCallback callback, ///< function to be called when registration completes gml_TPointer userData, ///< parameter to <callback> const char* regType, ///< type of service UInt16 port, ///< port associated with the service const char* name = (char*)NULL, ///< service name (a sensible default may be chosen) UInt32 interfaceIndex = (UInt32)0, ///< registration interface, -1 for local only gml_TSDMetaData* metaData = NULL ); /// GetAnswer -- /// /// Return the registration results. /// In particular, <name> and <domain> may have not been provided at <Init>. void GetAnswer (char** name, char** regtype, char** domain); private: /// HandlerEvent -- /// /// Called by <DNSServiceProcessResult> on incoming events. /// @see <gml_TSDConnection::SocketNotifier>. static void HandlerEvent ( DNSServiceRef /*sdRef*/, DNSServiceFlags /*flags*/, DNSServiceErrorType errorCode, const char* name, const char* regType, const char* domain, void* context ); private: char fName [GML_MAX_NAME_LENGTH+1]; ///< registered service name char fRegType [GML_MAX_TYPE_LENGTH+1]; ///< registered service type char fDomain [GML_MAX_HOST_LENGTH+1]; ///< registered service domain }; /////////////////////////////////////////////////////////////////////////////// #pragma mark - #pragma mark Service name resolution /// /// gml_TSDResolver -- /// /// Determine the host, port and metadata of a named service. /// class gml_TSDResolver : public gml_TSDConnection { public: /// Init -- /// /// Setup a new SD resolver. gml_TError Init ( gml_TCallback callback, ///< function to be called when resolution completes gml_TPointer userData, ///< parameter to <callback> const char* name, ///< name of service to resolve const char* regType, ///< type of service to resolve const char* domain = "local.", ///< domain where to resolve UInt32 interfaceIndex = (UInt32)0 ///< resolution interface, -1 for local only ); /// GetAnswer -- /// /// Return information about the resolved service. void GetAnswer (char** fullname, char** hostname, UInt16* port, gml_TSDMetaData** data); private: /// HandlerEvent -- /// /// Called by <DNSServiceProcessResult> on incoming events. /// @see <gml_TSDConnection::SocketNotifier>. static void HandlerEvent ( DNSServiceRef /*sdRef*/, DNSServiceFlags /*flags*/, uint32_t /*interfaceIndex*/, DNSServiceErrorType errorCode, const char* fullname, const char* hosttarget, uint16_t port, uint16_t txtLen, void* txtRecord, void* context ); public: char fFullName[GML_MAX_HOST_LENGTH+1]; char fHostName[GML_MAX_HOST_LENGTH+1]; UInt16 fPort; gml_TSDMetaData* fMetaData; }; #endif /* __GML_SERVICE_DISCOVERY__ */ Generated on Tue Jun 12 14:03:27 2007 for gml by Doxygen 1.5.2.

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