You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
pollen/scribblings/cache.scrbl

52 lines
2.4 KiB
Plaintext

11 years ago
#lang scribble/manual
11 years ago
@(require scribble/eval pollen/cache pollen/world (for-label racket (except-in pollen #%module-begin) pollen/world pollen/cache pollen/render pollen/file sugar))
11 years ago
@(define my-eval (make-base-eval))
@(my-eval `(require pollen))
11 years ago
@title{Cache}
11 years ago
@defmodule[pollen/cache]
11 years ago
The slowest part of a @racket[render] is parsing and decoding the source file. Often, previewing a single source file necessarily means decoding others (for instance templates, or other source files that are linked into the main source file). But usually, only one source file is changing at a time. Therefore, Pollen stores copies of the exports of source files — namely, whatever is stored in @code[(format "~a" world:main-pollen-export)] and @code[(format "~a" world:meta-pollen-export)] — in the cache so they can be reused.
@defparam[current-cache hash hash?
#:value (make-cache)]{A parameter that refers to the current cache. It is initialized with @racket[make-cache].
The cache is a hash table that uses the complete path of a source file as its keys. The value associated with each of these keys is a subcache — another hash table with keys @racket['doc], @racket['metas] (for storing the exports of the source file) and @racket['mod-time] (for storing the modification time, provided by @racket[file-or-directory-modify-seconds]).}
11 years ago
@defproc[
(cached-require
[source-path pathish?]
[key (or/c 'doc 'metas 'mod-time)])
(or/c txexpr? hash? integer?)]
11 years ago
Similar to @racket[(dynamic-require _source-path _key)], except that it first tries to retrieve the requested value out of @racket[current-cache]. If it's not there, or out of date, @racket[dynamic-require] is used to update the value.
11 years ago
11 years ago
The only keys supported are @racket['doc], @racket['metas], and @racket['mod-time].
11 years ago
11 years ago
If you want the speed benefit of the cache, you should @bold{always} use @racket[cached-require] to get data from Pollen source files. That doesn't mean you can't still use functions like @racket[require], @racket[local-require], and @racket[dynamic-require]. They'll just be slower.
11 years ago
@defproc[
(make-cache)
hash?]
Initializes @racket[current-cache].
@defproc[
(reset-cache)
void?]
Clears @racket[current-cache]. When only the nuclear option will do.
@defproc[
(cache-ref
[source-path pathish?])
hash?]
11 years ago
Returns the subcache associated with the key @racket[_source-path], which will itself be a hash table. See @racket[current-cache].
11 years ago