Signed-off-by: NJosé Valim <jose.valim@gmail.com>

[#5486 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

More work still needs to be done on some of these names
(render_template.action_view and render_template!.action_view particularly)
but this allows (for example) /^sql/ to subscribe to all
the various ORMs without further modification
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

All Caches

* Add default options to initializer that will be sent to all read, write, fetch, exist?, increment, and decrement
* Add support for the :expires_in option to fetch and write for all caches. Cache entries are stored with the create timestamp and a ttl so that expiration can be handled independently of the implementation.
* Add support for a :namespace option. This can be used to set a global prefix for cache entries.
* Deprecate expand_cache_key on ActiveSupport::Cache and move it to ActionController::Caching and ActionDispatch::Http::Cache since the logic in the method used some Rails specific environment variables and was only used by ActionPack classes. Not very DRY but there didn't seem to be a good shared spot and ActiveSupport really shouldn't be Rails specific.
* Add support for :race_condition_ttl to fetch. This setting can prevent race conditions on fetch calls where several processes try to regenerate a recently expired entry at once.
* Add support for :compress option to fetch and write which will compress any data over a configurable threshold.
* Nil values can now be stored in the cache and are distinct from cache misses for fetch.
* Easier API to create new implementations. Just need to implement the methods read_entry, write_entry, and delete_entry instead of overwriting existing methods.
* Since all cache implementations support storing objects, update the docs to state that ActiveCache::Cache::Store implementations should store objects. Keys, however, must be strings since some implementations require that.
* Increase test coverage.
* Document methods which are provided as convenience but which may not be universally available.

MemoryStore

* MemoryStore can now safely be used as the cache for single server sites.
* Make thread safe so that the default cache implementation used by Rails is thread safe. The overhead is minimal and it is still the fastest store available.
* Provide :size initialization option indicating the maximum size of the cache in memory (defaults to 32Mb).
* Add prune logic that removes the least recently used cache entries to keep the cache size from exceeding the max.
* Deprecated SynchronizedMemoryStore since it isn't needed anymore.

FileStore

* Escape key values so they will work as file names on all file systems, be consistent, and case sensitive
* Use a hash algorithm to segment the cache into sub directories so that a large cache doesn't exceed file system limits.
* FileStore can be slow so implement the LocalCache strategy to cache reads for the duration of a request.
* Add cleanup method to keep the disk from filling up with expired entries.
* Fix increment and decrement to use file system locks so they are consistent between processes.

MemCacheStore

* Support all keys. Previously keys with spaces in them would fail
* Deprecate CompressedMemCacheStore since it isn't needed anymore (use :compress => true)

[#4452 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

This reverts commit 8cbf8254.

  * Move #set_cookie and #delete_cookie inline to optimize. These optimizations should
    almost certainly be sent back upstream to Rack. The optimization involves using
    an ivar for cookies instead of indexing into the headers each time.
  * Was able to use a bare Hash for headers now that cookies have their own joining
    semantics (some code assumed that the raw cookies were an Array).
  * Cache blankness of body on body=
  * Improve expand_cache_key for Arrays of a single element (common in our case)
  * Use a simple layout condition check unless conditions are used
  * Cache visible actions
  * Lazily load the UrlRewriter
  * Make etag an ivar that is set on prepare!

Fixes bug where Memcached connections get corrupted when an invalid expire is passed in [#2854 state:resolved]

This reverts commit be1dbf32.

Signed-off-by: NDavid Heinemeier Hansson <david@loudthinking.com>

Decouple the local cache strategy from MemCacheStore for reuse with other remote stores [#1653 state:resolved]
Signed-off-by: NJoshua Peek <josh@joshpeek.com>