From 4bc603bbf3665ea523c4840438de70f2014e3e0c Mon Sep 17 00:00:00 2001
From: randomdan <randomdan@localhost>
Date: Wed, 25 Apr 2012 18:43:27 +0000
Subject: Unlinking cache file invalidates cache (bug18) Fix possible race
 condition truncating cache file on update Correct config section name

---
 project2/files/presenterCache.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/project2/files/presenterCache.cpp b/project2/files/presenterCache.cpp
index 8838568..e203fc4 100644
--- a/project2/files/presenterCache.cpp
+++ b/project2/files/presenterCache.cpp
@@ -16,6 +16,7 @@
 SimpleSysCallException(OpenCacheFile);
 SimpleSysCallException(StatCacheFile);
 SimpleSysCallException(LockCacheFile);
+SimpleSysCallException(TruncateCacheFile);
 SimpleSysCallException(CacheFileXAttr);
 
 template <class E>
@@ -47,7 +48,12 @@ class FilePresenterCache : public PresenterCache, public StaticContent, public S
 					readcachefd = safesys<OpenCacheFile>(-1, open(getCacheFile().string().c_str(), O_RDONLY));
 				}
 				struct stat st;
-				safesys<CacheFileXAttr>(-1, fstat(readcachefd, &st));
+				safesys<StatCacheFile>(-1, fstat(readcachefd, &st));
+				if (st.st_nlink == 0) {
+					close(readcachefd);
+					readcachefd = 0;
+					readcachefd = safesys<OpenCacheFile>(-1, open(getCacheFile().string().c_str(), O_RDONLY));
+				}
 				if (st.st_mtime < time(NULL) - FilePresenterCache::CacheLife) {
 					unlink(getCacheFile().string().c_str());
 					close(readcachefd);
@@ -99,8 +105,9 @@ class FilePresenterCache : public PresenterCache, public StaticContent, public S
 		std::ostream & writeCache(const std::string & ct, const std::string & enc)
 		{
 			int fd = safesys<OpenCacheFile>(-1, open(getCacheFile().string().c_str(),
-						O_CREAT | O_TRUNC | O_WRONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP));
+						O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP));
 			safesys<LockCacheFile>(-1, ::flock(fd, LOCK_EX));
+			safesys<TruncateCacheFile>(-1, ::ftruncate(fd, 0));
 			safesys<CacheFileXAttr>(-1, fsetxattr(fd, "user.content-type", ct.c_str(), ct.length(), 0));
 			safesys<CacheFileXAttr>(-1, fsetxattr(fd, "user.encoding", enc.c_str(), enc.length(), 0));
 			writecache = new boost::iostreams::stream<boost::iostreams::file_descriptor_sink>(fd, boost::iostreams::close_handle);
@@ -148,7 +155,7 @@ time_t FilePresenterCache::CacheLife;
 class FilePresenterCacheLoader : public ElementLoader::For<FilePresenterCache> {
 	public:
 		FilePresenterCacheLoader() :
-			opts("XML Cache options")
+			opts("File Presenter Cache options")
 		{
 			opts
 				("pcache.file.store", Options::value(&FilePresenterCache::Store, "/tmp/project2.pcache"),
-- 
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