mirror of
https://github.com/netsurf-browser/netsurf
synced 2024-12-03 11:21:55 +03:00
57 lines
2.2 KiB
Plaintext
57 lines
2.2 KiB
Plaintext
NetSurf fetch, cache, and content system
|
|
========================================
|
|
|
|
There is a one-to-one mapping between URLs and content structures.
|
|
|
|
The resource at a URL may be required for two reasons:
|
|
|
|
1. The user requests a URL in the GUI by entering it or following a link.
|
|
2. A page contains an object (such as an image).
|
|
|
|
When a URL is required, call fetchcache() as follows:
|
|
|
|
c = fetchcache(url, referer, callback, p1, p2, width, height);
|
|
|
|
p1 and p2 are the callers private pointers used to identify the resource, and
|
|
they are passed to the callback. The triple (callback, p1, p2) must be unique.
|
|
The call returns immediately with a struct content. The structure may be in the
|
|
following states (c->status):
|
|
|
|
CONTENT_STATUS_TYPE_UNKNOWN -- the MIME type of the resource has not been
|
|
determined yet.
|
|
|
|
CONTENT_STATUS_LOADING -- the resource is being fetched or converted, and can
|
|
not be displayed.
|
|
|
|
CONTENT_STATUS_READY -- the resource is still loading, but may be displayed.
|
|
|
|
CONTENT_STATUS_DONE -- the resource has loaded completely.
|
|
|
|
States may only follow in the above order (but some may be skipped). The
|
|
callback function is called when the state changes or at other times as follows:
|
|
|
|
CONTENT_MSG_LOADING -- state has changed from CONTENT_STATUS_TYPE_UNKNOWN to
|
|
CONTENT_STATUS_LOADING. If the type is not acceptable content_remove_user()
|
|
should be called (see below).
|
|
|
|
CONTENT_MSG_READY -- state has changed to CONTENT_STATUS_READY.
|
|
|
|
CONTENT_MSG_DONE -- state has changed to CONTENT_STATUS_DONE.
|
|
|
|
CONTENT_MSG_ERROR -- a fatal error with the resource has occurred. The error
|
|
message is in the callback parameter. The content structure will be
|
|
destroyed after this message and must not be used.
|
|
|
|
CONTENT_MSG_STATUS -- the content structure's status message has changed.
|
|
|
|
CONTENT_MSG_REDIRECT -- the server has sent a replacement URL for the content.
|
|
This message may only occur in CONTENT_STATUS_TYPE_UNKNOWN. The content
|
|
will be destroyed and must not be used.
|
|
|
|
If at any time the resource is no longer required, call content_remove_user():
|
|
|
|
content_remove_user(c, callback, p1, p2);
|
|
|
|
with the same callback, p1, p2 as passed to fetchcache().
|
|
|