X-Git-Url: http://www.project-moonshot.org/gitweb/?a=blobdiff_plain;f=xmltooling%2Futil%2FReloadableXMLFile.h;h=bce4b8e4b6d59c8ae88ed4decc874a9ae3ecf7db;hb=a0d768778a8f5f539b909baf5b115e70ea765f0f;hp=68aac2802f8b8560c833d81303ad0a2e90fb5506;hpb=5cb314df178f78c6fa7b9826c2c5a5298ec7a473;p=shibboleth%2Fcpp-xmltooling.git

diff --git a/xmltooling/util/ReloadableXMLFile.h b/xmltooling/util/ReloadableXMLFile.h
index 68aac28..bce4b8e 100644
--- a/xmltooling/util/ReloadableXMLFile.h
+++ b/xmltooling/util/ReloadableXMLFile.h
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2007 Internet2
+ *  Copyright 2001-2010 Internet2
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,8 +23,8 @@
 #ifndef __xmltooling_reloadable_h__
 #define __xmltooling_reloadable_h__
 
+#include <xmltooling/logging.h>
 #include <xmltooling/Lockable.h>
-#include <xmltooling/util/Threads.h>
 
 #include <ctime>
 #include <string>
@@ -32,13 +32,16 @@
 
 namespace xmltooling {
 
+    class XMLTOOL_API CondWait;
+    class XMLTOOL_API RWLock;
+    class XMLTOOL_API Thread;
+
     /**
      * Base class for file-based XML configuration.
      */
     class XMLTOOL_API ReloadableXMLFile : protected virtual Lockable
     {
-        MAKE_NONCOPYABLE(ReloadableXMLFile);
-        
+    MAKE_NONCOPYABLE(ReloadableXMLFile);
     protected:
         /**
          * Constructor taking a DOM element supporting the following content:
@@ -51,16 +54,21 @@ namespace xmltooling {
          *  <dt>validate</dt>
          *  <dd>use a validating parser</dd>
          *  <dt>reloadChanges</dt>
-         *  <dd>enables monitoring of resources for changes</dd>
+         *  <dd>enables monitoring of local file for changes</dd>
+         *  <dt>reloadInterval</dt>
+         *  <dd>enables periodic refresh of remote file</dd>
+         *  <dt>backingFilePath</dt>
+         *  <dd>location for backup of remote resource</dd>
+         *  <dt>id</dt>
+         *  <dd>identifies the plugin instance for logging purposes</dd>
          * </dl>
          * 
-         * @param e DOM to supply configuration
+         * @param e     DOM to supply configuration
+         * @param log   logging object to use
          */
-        ReloadableXMLFile(const xercesc::DOMElement* e);
+        ReloadableXMLFile(const xercesc::DOMElement* e, logging::Category& log);
     
-        virtual ~ReloadableXMLFile() {
-            delete m_lock;
-        }
+        virtual ~ReloadableXMLFile();
 
         /**
          * Loads configuration material.
@@ -68,20 +76,45 @@ namespace xmltooling {
          * <p>This method is called to load configuration material
          * initially and any time a change is detected. The base version
          * performs basic parsing duties and returns the result.
+         *
+         * <p>This method is not called with the object locked, so actual
+         * modification of implementation state requires explicit locking within
+         * the method override.
          * 
          * @return a pair consisting of a flag indicating whether to take ownership of
          *      the document, and the root element of the tree to load
          */
-        virtual std::pair<bool,xercesc::DOMElement*> load();
-        
+        virtual std::pair<bool,xercesc::DOMElement*> background_load();
+
         /**
-         * Overrideable method to determine whether a remote resource remains valid.
+         * Basic load/parse of configuration material.
+         * 
+         * <p>The base version performs basic parsing duties and returns the result.
+         * Subclasses should override the new background_load() method and perform
+         * their own locking in conjunction with use of this method.
+         *
+         * <p>Subclasses that continue to override this method will function, but
+         * a write lock will be acquired and held for the entire operation.
          * 
-         * @return  true iff the resource remains valid and should not be reloaded
+         * @return a pair consisting of a flag indicating whether to take ownership of
+         *      the document, and the root element of the tree to load
+         */
+        virtual std::pair<bool,xercesc::DOMElement*> load();
+
+        /**
+         * Accesses a lock interface protecting use of backup file associated with the
+         * object.
+         *
+         * <p>The lock is <strong>NOT</strong> acquired automatically.
+         *
+         * @return  pointer to a lock interface, or nullptr if unnecessary
+         */
+        virtual Lockable* getBackupLock();
+
+        /**
+         * Shuts down reload thread, should be called from subclass destructor.
          */
-        virtual bool isValid() const {
-            return true;
-        }
+        void shutdown();
 
         /** Root of the original DOM element passed into constructor. */
         const xercesc::DOMElement* m_root;
@@ -94,20 +127,46 @@ namespace xmltooling {
         
         /** Resource location, may be a local path or a URI. */
         std::string m_source;
-        
+
+        /** Path to backup copy for remote resource. */
+        std::string m_backing;
+
+        /**
+         * Before load, indicates whether the backup is handled by the base class,
+         * after load, will be true iff it started false and a backup needs to be done.
+         */
+        bool m_backupIndicator;
+
         /** Last modification of local resource. */
         time_t m_filestamp;
-        
+
+        /** Time in seconds to wait before trying for new copy of remote resource. */
+        time_t m_reloadInterval;
+
+        /** Caching tag associated with remote resource. */
+        std::string m_cacheTag;
+
         /** Shared lock for guarding reloads. */
         RWLock* m_lock;
+        
+        /** Logging object. */
+        logging::Category& m_log;
+
+        /** Plugin identifier. */
+        std::string m_id;
 
     public:
         Lockable* lock();
+        void unlock();
+
+    private:
+        std::pair<bool,xercesc::DOMElement*> load(bool backup);
 
-        void unlock() {
-            if (m_lock)
-                m_lock->unlock();
-        }
+        // Used to manage background reload/refresh.
+        bool m_shutdown;
+        CondWait* m_reload_wait;
+        Thread* m_reload_thread;
+        static void* reload_fn(void*);
     };
 
 };