Maiden-Storage

About Maiden-Storage

This offers convenient persistent and thread-safe storage for Maiden components.

How To

For the most part you will want to refer to Ubiquitous for docs, since that is the underlying system used for persistence and storage management.

Time for a simple example.

 (maiden:define-consumer tester () ())

The with-storage macro takes care of establishing the proper context where the storage is accessible through value.

 (maiden:define-instruction (tester write-storage) (c ev field value)
   (maiden-storage:with-storage (c)
     (setf (maiden-storage:value field) value)))

 (maiden:define-query (tester read-storage) (c ev field)
   (maiden-storage:with-storage (c)
     (maiden-storage:value field)))

Let's construct a test case.

 (defvar *core* (maiden:make-simple-core 'tester))

 (write-storage *core* :test "Hey!")
 (read-storage *core* :test)

As apparent, the access works as intended. Just to make sure things are also persisted to disk, let's check that out.

 (alexandria:read-file-into-string (ubiquitous:designator-pathname 'tester :lisp))

And sure enough the file is filled with the info we stored.

Copyright

maiden-storage is licensed under the Artistic license. © Nicolas Hafner <shinmera@tymoon.eu> . This library can be obtained on https://github.com/Shinmera/maiden.

Package Index

MAIDEN-STORAGE (ORG.SHIRAKUMO.MAIDEN.MODULES.STORAGE)

special

`STORAGE`

Special variable containing the current root storage object.
Defaults to an EQUAL hash-table.

accessor (

`STORAGE`

THING)

Accesses the storage object for the given thing. If the storage has not yet been loaded, NIL is returned.

See *STORAGES*

accessor (

`VALUE`

&REST PATH)

Traverses *STORAGE* by the fields in PATH and returns the value if it can be found.
The secondary return value is a boolean depicting whether the field could be found.

This is SETF-able. If a PATH is set that is made up of fields that do not exist yet,
then these fields are automatically created as necessary (if possible) by usage of
AUGMENT. Setting with no PATH given sets the value of *STORAGE*. After setting a value,
OFFLOAD is called, unless *COMMIT* is NIL

See FIELD
See AUGMENT
See OFFLOAD
See *COMMIT*

function (

`OFFLOAD`

DESIGNATOR &OPTIONAL (STORAGE (STORAGE DESIGNATOR)))

Saves the storage for the given designator to disk.

The storage is always serialised under the MAIDEN-USER
package.

See UBIQUITOUS:OFFLOAD
See CONFIG-PATHNAME
See STORAGE

function (

`RELOAD`

&OPTIONAL DESIGNATOR)

Causes the configuration to be reloaded.

If DESIGNATOR is NIL, then the configuration is reloaded
for everything.

The configuration is not immediately reloaded. The reloading
is deferred until the storage in question is actually needed.

See STORAGE
See *STORAGES*

function (

`RESTORE`

DESIGNATOR)

Restores the storage for the given designator from disk.

See UBIQUITOUS:RESTORE
See CONFIG-PATHNAME

generic (
CONFIG-PATHNAME
PATHNAME)
```
 
```

generic (

`DEFAULTED-VALUE`

DEFAULT &REST PATH)

Same as VALUE, but automatically returns and sets DEFAULT if the field cannot be found.

See VALUE

generic (

`REMVALUE`

&REST PATH)

Removes the value denoted by the PATH.
The secondary return value is a boolean depicting whether the field could be found.

First traverses *STORAGE* until the last field in PATH by FIELD, then uses REMFIELD
on the last remaining field. If no PATH is given, the *STORAGE* is reset to an empty
hash-table.

See FIELD
See REMFIELD

macro (

`DEFINE-STORED-ACCESSOR`

&REST ARGS)

Define an accessor that defers to the storage instead of the object's slot.

See WITH-STORAGE

macro (

`WITH-STORAGE`

&REST ARGS)

Ensure the storage is available within the body.

The designator determines for "what" the configuration is.
If ALWAYS-LOAD is non-NIL, then the storage is first loaded
from disk every time.

See CONFIG-PATHNAME
See ENSURE-STORAGE
See UBIQUITOUS:WITH-LOCAL-STORAGE