Use apr_pstrmemdup instead of apr_pstrndup when this is safe.

Only close hdrs.fd when returning non-OK from cache_select(), because it will be read from in the very next mod_cache callback recall_headers(). Problem masked on unix by buffering.

mod_cache: Ensure that updated responses to HEAD requests don't get mistakenly paired with a previously cached body. Ensure that any existing body is removed when a HEAD request is cached.

mod_cache: Invalidate cached entities in response to RFC2616 Section 13.10 Invalidation After Updates or Deletions. PR 15868 Resolves outstanding issue with r1070179 as per http://www.gossamer-threads.com/lists/apache/dev/395830?do=post_view_threaded#395830

Name pool + concat string at compile time when possible

fix merge of min/max file size by setting corresponding _set

Remove useless tests. Turn if (*x && apr_isspace(*x)) into if (apr_isspace(*x))

* fd is no member of disk_cache_object_t. Instead it is a member of disk_cache_file_t. Close all fd's (fd, tempfd) for all cache elements (hdrs, data, vary) if they are present.

*) mod_cache_disk: Resolve errors while revalidating disk-cached files on Windows ("...rename tempfile to datafile failed..."). PR 38827 [Eric Covener]

Replace use of apr_file_write() with apr_file_write_full() to prevent incomplete writes. Add comments in some places where error handling/logging is missing. PR: 53131. Submitted by: Nicolas Viennot <apache viennot biz>, Stefan Fritsch

Add lots of unique tags to error log messages

mod_cache: Apply the API change that allows future mod_cache providers to invalidate cache entries, which will fix PR15868.

Remove more log message prefixes that are now redundant as the the error log format includes the module name.

mod_cache_disk: Make sure we check return codes on all writes and attempts to close, and clean up after ourselves in these cases. PR43589.

mod_cache_disk: Remove the unnecessary intermediate brigade while writing to disk. Fixes a problem where mod_disk_cache was leaving buckets in the intermediate brigade and not passing them to out on exit.

Consistently use base 10 for numbers when parsing config options. It may be confusing to the user if some directives treat a number with leading zero as octal while most don't.

Introduce ap_(get|set)_core_module_config() functions/macros and use them everywhere. We know that the core module has module_index 0. Therefore we can save some pointer operations in ap_get_module_config(cv, &core_module) and ap_set_module_config(cv, &core_module, val). As these are called rather often, this may actually have some (small) measurable effect.

mod_cache_disk: Prevent a segfault should we receive a further bucket after we have committed the cached entry.

mod_cache_disk: Only attempt to commit to the initialisation if the attempt to open the cache file was successful.

Further trivial updates mod_disk_cache -> mod_cache_disk. No functional change.

Rename disk_cache to cache_disk within logging statements.

mod_disk_cache renamed to mod_cache_disk, to be consistent with the naming of other modules.