Class

CamelDataCache

Description [src] 

class Camel.DataCache : GObject.Object
{
  CamelDataCachePrivate* priv
}

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));
    }

camel_data_cache_add_atomic() writes to a temporary file in the same directory as the target, so camel_data_cache_commit_atomic() can rename it into place atomically. Any concurrent camel_data_cache_get() call for the same item blocks until the write is either committed or discarded.

Hierarchy

hierarchy this CamelDataCache ancestor_0 GObject ancestor_0--this

Ancestors

Constructors

camel_data_cache_new

Create a new data cache.

Instance methods

camel_data_cache_add_atomic

Open a temporary file for writing a new cache item identified by path and key. The temporary file lives in the same directory as the final target so that camel_data_cache_commit_atomic() can rename it into place atomically (same-filesystem rename).

unstable since: 3.62

camel_data_cache_clear

Clear cache’s content in path.

since: 3.2

camel_data_cache_commit_atomic

Finalise an atomic cache write. stream is closed and unreffed, the temporary file is renamed to its final location, and a new GIOStream opened on the committed file is returned (equivalent to calling camel_data_cache_get() after a successful write).

unstable since: 3.62

camel_data_cache_discard_atomic

Discard an atomic cache write. stream is closed and unreffed, the temporary file is removed, and the bag reservation is released so that other threads can retry the operation.

unstable since: 3.62

camel_data_cache_foreach_remove

Traverses the cdc sub-cache identified by path and calls func for each found file. If the func returns TRUE, then the file is removed, if FALSE, it’s kept in the cache.

since: 3.26

camel_data_cache_get

Lookup an item in the cache. If the item exists, a GIOStream is returned for the item. The stream may be shared by multiple callers, so ensure the stream is in a valid state through external locking.

camel_data_cache_get_expire_enabled

Gets whether expire of cache data is enabled.

since: 3.24

camel_data_cache_get_filename

Lookup the filename for an item in the cache.

since: 2.26

camel_data_cache_get_path

Returns the path to the data cache.

since: 2.32

camel_data_cache_remove

Remove/expire a cache item.

camel_data_cache_set_expire_access

Set the cache expiration policy for access times.

camel_data_cache_set_expire_age

Set the cache expiration policy for aged entries.

camel_data_cache_set_expire_enabled

Sets whether expire of cache data is enabled.

since: 3.24

camel_data_cache_set_path

Sets the path to the data cache.

since: 2.32

Methods inherited from GObject (43)

Please see GObject for a full list of methods.

Properties

Signals

Signals inherited from GObject (1)
GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.

Class structure 

struct CamelDataCacheClass {
  GObjectClass parent_class;
  gpointer reserved;
  
}

No description available.

Class members
parent_class: GObjectClass

No description available.

reserved: gpointer

No description available.