DataCache

Object Hierarchy:

Description:

[ CCode ( type_id = "camel_data_cache_get_type ()" ) ]
public class DataCache : Object

A file-based cache for arbitrary keyed data, typically used by mail providers to store downloaded message bodies.

Each item is identified by a (path, key) pair. The path selects a logical sub-cache (e.g. `"cur"` for downloaded messages, `"new"` for outgoing spool), and key is a per-item identifier such as a message UID.

To write a new item safely — so that a crash or cancellation never leaves a truncated file in the cache — use the atomic write API:

    GIOStream *stream;
    gboolean success;

    stream = camel_data_cache_add_atomic (cache, "cur", uid, error);
    if (!stream)
        goto fail;

    success = write_message_to_stream (G_OUTPUT_STREAM (
        g_io_stream_get_output_stream (stream)), message, error);

    if (success) {
        stream = camel_data_cache_commit_atomic (cache, g_steal_pointer (&stream), error);
        /<!-- -->* stream is now open on the committed file, or NULL on error *<!-- -->/
    } else {
        camel_data_cache_discard_atomic (cache, g_steal_pointer (&stream));
    }

add_atomic writes to a temporary file in the same directory as the target, so commit_atomic can rename it into place atomically. Any concurrent @get call for the same item blocks until the write is either committed or discarded.

Namespace: Camel

Package: camel-1.2

Content:

Properties:

public bool expire_enabled { get; set construct; }
Expire Enabled
public string path { get; set construct; }
Path

Creation methods:

public DataCache (string path) throws Error
Create a new data cache.

Methods:

public IOStream @get (string path, string key) throws Error
Lookup an item in the cache.
public IOStream add_atomic (string path, string key) throws Error
Open a temporary file for writing a new cache item identified by path and key.
public void clear (string path)
Clear cache's content in path.
public IOStream commit_atomic (owned IOStream stream) throws Error
Finalise an atomic cache write.
public void discard_atomic (owned IOStream stream)
Discard an atomic cache write.
public void foreach_remove (string path, DataCacheRemoveFunc func)
Traverses the this sub-cache identified by path and calls func for each found file.
public bool get_expire_enabled ()
Gets whether expire of cache data is enabled.
public string get_filename (string path, string key)
Lookup the filename for an item in the cache
public unowned string get_path ()
Returns the path to the data cache.
public int remove (string path, string key) throws Error
Remove/expire a cache item.
public void set_expire_access (time_t when)
Set the cache expiration policy for access times.
public void set_expire_age (time_t when)
Set the cache expiration policy for aged entries.
public void set_expire_enabled (bool expire_enabled)
Sets whether expire of cache data is enabled.
public void set_path (string path)
Sets the path to the data cache.

Inherited Members:

All known members inherited from class GLib.Object