Refactor Clear/Purge/Wipe

[jaswrks]

See also: #288

Summary of New Class Members

• New constants...
  • \quick_cache\share::CACHE_PATH_REGEX_DEFAULT_SUFFIX_FRAG
• New properties...
  • \quick_cache\share::$name = (string)Quick Cache
  • \quick_cache\share::$short_name = (string)QC
  • \quick_cache\share::$slug (moved into the share class, was in the plugin class).
• New methods for network-wide clearing/purging/wiping.
  • \quick_cache\share::build_cache_path_regex() - utility.
  • \quick_cache\share::clear_files_from_cache_dir() - simple wrapper.
  • \quick_cache\share::purge_files_from_cache_dir() - simple wrapper.
  • \quick_cache\share::delete_files_from_cache_dir() - a meaty routine.
• New methods for host/blog-specific clearing/purging/wiping.
  • \quick_cache\share::build_host_cache_path_regex() - utility.
  • \quick_cache\share::build_host_cache_path_regex_frags_from_wc_uris() - utility.
  • \quick_cache\share::clear_files_from_host_cache_dir() - simple wrapper.
  • \quick_cache\share::purge_files_from_host_cache_dir() - simple wrapper.
  • \quick_cache\share::delete_files_from_host_cache_dir() - a meaty routine.
• New method for recursively deleting a directory.
  • \quick_cache\share::delete_all_files_dirs_in() - a meaty routine.
• New methods to assist in translations.
  • \quick_cache\share::i18n_files() - utility.
  • \quick_cache\share::i18n_dirs() - utility.
  • \quick_cache\share::i18n_files_dirs() - utility.
• New string utilities.
  • \quick_cache\share::str_replace_once() - utility.
  • \quick_cache\share::str_ireplace_once() - utility.
  • \quick_cache\share::add_tmp_suffix() - utility.
• New version-specific upgrader.
  • \quick_cache\version_specific_upgrade::from_lt_v141009() - handles option key changes.

Summary of Changes

• Refactored all \quick_cache\plugin::auto_purge_*() methods. These now take advantage of the new methods in the \quick_cache\share class. Clearing/purging/wiping is now atomic in all scenarios.
• Renamed all \quick_cache\plugin::auto_purge_* methods, giving them the proper prefix of auto_clear_* instead. Along with this, all of the auto_purge_ option keys have been renamed as well. In addition, the UI, descriptions, internal coments, docBlocks, etc. have been updated to the correct terminology.
• Refactored \quick_cache\advanced_cache\maybe_invalidate_when_logged_in_postload() to take advantage of new methods in the \quick_cache\share class. Clearing (i.e. invalidation) is now atomic here as well.
• All URI and Referrer exclusion patterns are now caSe insensitive. This was part of the refactoring here as well. WordPress v4 will serve URIs w/o cAse sensitivity. s2Member was updated just recently to support this too. With this PR for QC, all of the Quick Cache codebase has now been updated to support caSe insensitive clearing/purging/wiping; along with caSe insensitive pattern matching against URIs. The UI and instructions were updated for URIs exclusions patterns, and for Referrer exclusion patterns.
• I also fixed a newly-discovered bug. The auto_purge_author_page_cache() method (now auto_clear_author_page_cache()) was presenting dashboard notices in the pro version, even when change_notifications_enable was off.
• I also fixed a newly-discovered bug. The auto_purge_custom_post_type_archive_cache() method (now auto_clear_custom_post_type_archive_cache()) was not checking for the $post_id in $this->static[__FUNCTION__]. Should be $this->static[__FUNCTION__][$post_id].
• A new class file (/includes/utils-feed.php) was added while I was working to refactor the XML feed clearing routine. With these utilities in place, the auto_clear_xml_feeds_cache() method is now MUCH easier to deal with and comprehend.
• All dashboard notices will now include the number of files cleared for each notice.
• I left a couple of @TODO @raamdev notes in the source code for review at a later date.
• Refactored \quick_cache\plugin::wipe_*() and \quick_cache\plugin::clear_*() methods. These now take advantage of new methods in the \quick_cache\share class. As mentioned previously, all clearing/purging/wiping is atomic, and that includes these methods too. This work was actually done together with other changes to the auto_*() methods.

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Performance Enhancements

• With these changes, QC is now capable of doing atomic clearing/purging/wiping. In addition, on a MS network this is now accomplished on a blog-specific basis, without needing to scan the entire network-wide cache directory like before. This should improve performance considerably on large networks (i.e. those with VERY large cache directories).
  • There is one exception to this however. If user-specific caching is enabled, an automatic invalidation of the cache for a particular user is always done network-wide, because a user can be logged into a single child site in the network, but have data that is shared across all blogs. This requires QC to do a full network-wide scan whenever it clears the cache for a particular user. For this reason, it is suggested that VERY large networks with a HUGE cache directory, do NOT enable user-specific caching.
• With these changes, each scheme sub-directory; i.e. /http/ and /https/ is scanned separately to help break apart what was previously a much larger directory scan for sites that serve pages over both schemes. QC now does two scans, which in itself is a bit slower, but should actually work to improve performance overall. In short, we don't need to look at both variations of a site at the same time any longer, we now deal with clearing/purging for each scheme separately. This will improve performance on both standard and MS network installs.

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Tests Performed

• I tested each of the newly-refactored auto_clear_*() methods, along with various other things in both a standard WP install, and also on a MS network running sub-directories. Found a few minor issues and those were corrected in the last commit on this PR. Not seeing any remaining problems. I feel like this is ready to review; i.e. ready to merge and be tested further.

[raamdev]

@jaswsinc Wow! This is fantastic. Really great work. Thank you so much for all of this.

I have reviewed your notes and merged this PR and PR wpsharks/comet-cache-pro#90.

[raamdev]

Next release changelog:

• Enhancement: Refactored codebase to improve modularity by creating new methods in includes/share.php for network-wide clearing/purging/wiping, host/blog-specific clearing/purging/wiping, recursively deleting a directory, assisting in translations, and several new string utilities. Props @jaswsinc. See #351.
• Enhancement: Renamed all \quick_cache\plugin::auto_purge_* methods, giving them the proper prefix of auto_clear_* instead to reflect proper Wipe/Clear/Purge terminology. Along with this, all of the auto_purge_ option keys have been renamed as well. See new Wipe/Clear/Purge wiki article for a description of these terms. Props @jaswsinc. See #351.
• Enhancement: All URI and Referrer exclusion patterns are now caSe insensitive. WordPress v4.0 will serve URIs without cAse sensitivity. All of the Quick Cache codebase has been updated to support caSe insensitive clearing/purging/wiping; along with caSe insensitive pattern matching against URIs. Props @jaswsinc. See #351.
• Bug Fix (Pro): Fixed a bug with the Auto-Clear Author Cache routine that was presenting dashboard notices even when change_notifications_enable was off. Props @jaswsinc. See #351.
• Bug Fix: Fixed a bug in the Auto-Clear Custom Post Type Archive Cache that was not checking for the $post_id in $this->static[__FUNCTION__]. Props @jaswsinc. See #351.
• Enhancement: Added a new class file (/includes/utils-feed.php) and refactored the XML feed clearing routine. With these utilities in place, the auto_clear_xml_feeds_cache() method is now much easier to deal with and comprehend. Props @jaswsinc. See #351.
• Enhancement: All dashboard notices will now include the number of files cleared for each notice. Props @jaswsinc. See #351.
• Enhancement: Quick Cache is now capable of doing atomic clearing/purging/wiping. On a Multisite network, this is now accomplished on a blog-specific basis, without needing to scan the entire network-wide cache directory. This should improve performance considerably on large networks (i.e. those with VERY large cache directories). Props @jaswsinc. See #288 and #351.
• Enhancement: Quick Cache now scans each scheme sub-directory, i.e. /http/ and /https/, separately to help break apart what was previously a much larger directory scan for sites that serve pages over both schemes. This will improve performance on both standard and Multisite network installs. See #351.