/*
- * Copyright 2001-2006 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.
#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>
+#include <xercesc/dom/DOM.hpp>
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:
* <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 DOMElement* e);
+ ReloadableXMLFile(const xercesc::DOMElement* e, logging::Category& log);
- virtual ~ReloadableXMLFile() {
- delete m_lock;
- }
-
- public:
- Lockable* lock();
-
- void unlock() {
- if (m_lock)
- m_lock->unlock();
- }
+ virtual ~ReloadableXMLFile();
/**
* Loads configuration material.
* <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,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.
*
- * @return true iff the resource remains valid and should not be reloaded
+ * <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 a pair consisting of a flag indicating whether to take ownership of
+ * the document, and the root element of the tree to load
*/
- virtual bool isValid() const {
- return true;
- }
+ virtual std::pair<bool,xercesc::DOMElement*> load();
- private:
- const DOMElement* m_root;
- bool m_local, m_validate;
+ /**
+ * 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.
+ */
+ void shutdown();
+
+ /** Root of the original DOM element passed into constructor. */
+ const xercesc::DOMElement* m_root;
+
+ /** Indicates whether resources is local or remote. */
+ bool m_local;
+
+ /** Use a validating parser when parsing XML. */
+ bool m_validate;
+
+ /** 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);
+
+ // Used to manage background reload/refresh.
+ bool m_shutdown;
+ CondWait* m_reload_wait;
+ Thread* m_reload_thread;
+ static void* reload_fn(void*);
};
};
projects / shibboleth / cpp-xmltooling.git / blobdiff