Cache class for object, file or directory caching

A class to handle caching of objects, files, or directories. It generates a signature from the provided object and creates cached versions based on that signature.

Public fields

cache_dir

Directory where cached files are stored

source

path to the original file/directory/prefix

Methods

Public methods

• Cache$new()

• Cache$clear()

• Cache$clear_all()

• Cache$restore()

• Cache$is_cached()

• Cache$get_path()

• Cache$save()

• Cache$clone()

---

Method new()

Initialize a new Cache object

Usage

Cache$new(
  sig_object,
  prefix,
  cache_dir,
  save_sig = FALSE,
  kind = c("object", "file", "dir", "prefix"),
  path = NULL
)

Arguments

sig_object

Object used to generate the cache signature

prefix

Prefix for the cache filename

cache_dir

Directory where cached files are stored

save_sig

Whether to save the signature to a file

kind

Type of cache: "object", "file", "dir" or "prefix"

• object: cache an R object

• file: cache a file

• dir: cache a directory

• prefix: cache files/directories with the same prefix

path

Path to the file or directory to cache This is required when kind is "file", "dir", or "prefix"

Details

The sig_object is used to generate a unique signature for the cache. The signature is based on the structure of the object, which helps in determining if the cached version is still valid. The prefix is used to create a unique identifier for the cached files. The cache_dir is the directory where the cached files will be stored. If save_sig is TRUE, the signature will be saved to a file in the cache directory. The kind parameter determines how the cache will be handled:

• "object": The cache will store an R object.

• "file": The cache will store a file.

• "dir": The cache will store a directory.

• "prefix": The cache will store files/directories with the same prefix. The path parameter is required when kind is "file", "dir", or "prefix". It specifies the path to the file or directory to cache. If cache_dir is NULL or an empty string, caching will not be performed. If cache_dir is FALSE, caching will not be performed.

Returns

A new Cache object

Examples

\dontrun{
# Create a Cache object for an R object
cache <- Cache$new(sig_object = mtcars, prefix = "mtcars_cache",
                   cache_dir = tempdir(), save_sig = TRUE, kind = "object")
# Save the object to cache
cache$save(mtcars)
# Restore the cached object
cached_mtcars <- cache$restore()
# Check if the object is cached
cache$is_cached()  # Should return TRUE
# Clear the cache
cache$clear()
# Clear all cached objects in the cache directory
cache$clear_all()
}

---

Method clear()

Clear the current cached object/file/directory

Usage

Cache$clear()

---

Method clear_all()

Clear all cached objects in the cache directory Be careful with this operation as it will remove all cached files in the cache directory

Usage

Cache$clear_all()

---

Method restore()

Retrieve the cached object/file/directory When NULL is returned, it means the cache does not exist

Usage

Cache$restore()

Returns

The cached object if kind is "object", otherwise NULL

---

Method is_cached()

Check if we have a cached object/file/directory

Usage

Cache$is_cached()

Returns

TRUE if the cached object/file/directory exists, FALSE otherwise

---

Method get_path()

Get the path to the cached object/file/directory

Usage

Cache$get_path()

Returns

The path to the cached object/file/directory

---

Method save()

Save an object/file/directory/prefix to cache

Usage

Cache$save(data = NULL)

Arguments

data

The object to cache, or NULL for non-"object" kinds

---

Method clone()

The objects of this class are cloneable with this method.

Usage

Cache$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

## ------------------------------------------------
## Method `Cache$new`
## ------------------------------------------------

if (FALSE) { # \dontrun{
# Create a Cache object for an R object
cache <- Cache$new(sig_object = mtcars, prefix = "mtcars_cache",
                   cache_dir = tempdir(), save_sig = TRUE, kind = "object")
# Save the object to cache
cache$save(mtcars)
# Restore the cached object
cached_mtcars <- cache$restore()
# Check if the object is cached
cache$is_cached()  # Should return TRUE
# Clear the cache
cache$clear()
# Clear all cached objects in the cache directory
cache$clear_all()
} # }