From 8dc4bc6a7b3951c7b4c6cebd8be1e27a62d4297c Mon Sep 17 00:00:00 2001
From: Scott Cantor <cantor.2@osu.edu>
Date: Mon, 24 May 2010 22:38:30 +0000
Subject: [PATCH] https://issues.shibboleth.net/jira/browse/CPPOST-47

---
 .gitignore                            |  1 +
 xmltooling/util/ReloadableXMLFile.cpp | 34 ++++++++++++++++++++++++++++++----
 xmltooling/util/ReloadableXMLFile.h   |  6 ++++++
 3 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/.gitignore b/.gitignore
index e0b41a4..595639a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,3 +45,4 @@
 /*.gz
 /*.opensdf
 /*.sdf
+/ipch
diff --git a/xmltooling/util/ReloadableXMLFile.cpp b/xmltooling/util/ReloadableXMLFile.cpp
index 5aacc9a..2fdc7db 100644
--- a/xmltooling/util/ReloadableXMLFile.cpp
+++ b/xmltooling/util/ReloadableXMLFile.cpp
@@ -208,6 +208,18 @@ ReloadableXMLFile::ReloadableXMLFile(const DOMElement* e, Category& log, bool st
                 m_backing=temp2.get();
                 XMLToolingConfig::getConfig().getPathResolver()->resolve(m_backing, PathResolver::XMLTOOLING_RUN_FILE);
                 log.debug("backup remote resource to (%s)", m_backing.c_str());
+                try {
+                    ifstream backer(m_backing + ".tag");
+                    if (backer) {
+                        char cachebuf[256];
+                        if (backer.getline(cachebuf, 255)) {
+                            m_cacheTag = cachebuf;
+                            log.debug("loaded initial cache tag (%s)", m_cacheTag.c_str());
+                        }
+                    }
+                }
+                catch (exception&) {
+                }
             }
             source = e->getAttributeNS(nullptr,reloadInterval);
             if (!source || !*source)
@@ -421,9 +433,8 @@ pair<bool,DOMElement*> ReloadableXMLFile::load(bool backup)
                 if (XMLHelper::isNodeNamed(doc->getDocumentElement(), xmlconstants::XMLTOOLING_NS, URLInputSource::utf16StatusCodeElementName)) {
                     int responseCode = XMLString::parseInt(doc->getDocumentElement()->getFirstChild()->getNodeValue());
                     doc->release();
-                    if (responseCode == HTTPResponse::XMLTOOLING_HTTP_STATUS_NOTMODIFIED) {
+                    if (responseCode == HTTPResponse::XMLTOOLING_HTTP_STATUS_NOTMODIFIED)
                         throw (long)responseCode; // toss out as a "known" case to handle gracefully
-                    }
                     else {
                         m_log.warn("remote resource fetch returned atypical status code (%d)", responseCode);
                         throw IOException("remote resource fetch failed, check log for status code of response");
@@ -478,8 +489,9 @@ pair<bool,DOMElement*> ReloadableXMLFile::load()
             m_log.debug("backing up remote resource to (%s)", m_backing.c_str());
             try {
                 Locker locker(getBackupLock());
-                ofstream backer(m_backing.c_str());
+                ofstream backer(m_backing);
                 backer << *(ret.second->getOwnerDocument());
+                preserveCacheTag();
             }
             catch (exception& ex) {
                 m_log.crit("exception while backing up resource: %s", ex.what());
@@ -487,11 +499,13 @@ pair<bool,DOMElement*> ReloadableXMLFile::load()
         }
         return ret;
     }
-    catch (long&) {
+    catch (long& responseCode) {
         // If there's an HTTP error or the document hasn't changed,
         // use the backup iff we have no "valid" resource in place.
         // That prevents reload of the backup copy any time the document
         // hasn't changed.
+        if (responseCode == HTTPResponse::XMLTOOLING_HTTP_STATUS_NOTMODIFIED)
+            m_log.info("remote resource (%s) unchanged from cached version", m_source.c_str());
         if (!m_loaded && !m_backing.empty())
             return load(true);
         throw;
@@ -519,6 +533,18 @@ Lockable* ReloadableXMLFile::getBackupLock()
     return &XMLToolingConfig::getConfig();
 }
 
+void ReloadableXMLFile::preserveCacheTag()
+{
+    if (!m_cacheTag.empty() && !m_backing.empty()) {
+        try {
+            ofstream backer(m_backing + ".tag");
+            backer << m_cacheTag;
+        }
+        catch (exception&) {
+        }
+    }
+}
+
 #ifndef XMLTOOLING_LITE
 
 void ReloadableXMLFile::validateSignature(Signature& sigObj) const
diff --git a/xmltooling/util/ReloadableXMLFile.h b/xmltooling/util/ReloadableXMLFile.h
index 4301896..4f21177 100644
--- a/xmltooling/util/ReloadableXMLFile.h
+++ b/xmltooling/util/ReloadableXMLFile.h
@@ -151,6 +151,12 @@ namespace xmltooling {
         virtual Lockable* getBackupLock();
 
         /**
+         * Preserves the last remote resource caching identifier in a backup file
+         * for use on the next restart.
+         */
+        void preserveCacheTag();
+
+        /**
          * Starts up reload thread, can be automatically called by constructor, or
          * manually invoked by subclass.
          */
-- 
2.1.4