Public Anchor Object
/*
** (c) COPYRIGHT MIT 1995.
** Please first read the full copyright statement in the file COPYRIGH.
*/
An anchor represents a region of a hypertext document which is linked
to another anchor in the same or a different document. As always we
must emulate the fancy features of C++ by hand :-(. In this module you
find:
This module is implemented by HTAnchor.c, and
it is a part of the W3C
Reference Library.
#ifndef HTANCHOR_H
#define HTANCHOR_H
#include "HTList.h"
#include "HTAtom.h"
#include "HTMethod.h"
Types defined by the Anchor Object
This is a set of videly used type definitions used through out the
Library:
typedef struct _HTLink HTLink;
typedef HTAtom * HTFormat;
typedef HTAtom * HTLevel; /* Used to specify HTML level */
typedef HTAtom * HTEncoding; /* Content Encoding */
typedef HTAtom * HTCte; /* Content transfer encoding */
typedef HTAtom * HTCharset;
typedef HTAtom * HTLanguage;
typedef struct _HTAnchor HTAnchor;
typedef struct _HTParentAnchor HTParentAnchor;
typedef struct _HTChildAnchor HTChildAnchor;
The Link Object
Anchors are bound together using link objects. Each anchor can be the
source or destination of zero, one, or more links from and to other
anchors.
Link Destination
extern BOOL HTLink_setDestination (HTLink * link, HTAnchor * dest);
extern HTAnchor * HTLink_destination (HTLink * link);
Link Result
When a link has been used for posting an object from a source to a
destination link, the result of the operation is stored as part of the
link information.
typedef enum _HTLinkResult {
HT_LINK_INVALID = -1,
HT_LINK_NONE = 0,
HT_LINK_ERROR,
HT_LINK_OK
} HTLinkResult;
extern BOOL HTLink_setResult (HTLink * link, HTLinkResult result);
extern HTLinkResult HTLink_result (HTLink * link);
Link Method
The method used in a link can be PUT, or POST, for example
extern BOOL HTLink_setMethod (HTLink * link, HTMethod method);
extern HTMethod HTLink_method (HTLink * link);
Link Type
This is used for typed links.
typedef HTAtom * HTLinkType;
extern BOOL HTLink_setType (HTLink * link, HTLinkType type);
extern HTLinkType HTLink_type (HTLink * link);
Relations between Links and Anchors
Link this Anchor to another given one
A single anchor may have many outgoing links of which the default is
the main link. If one already exists then this new link is
simply added to the list.
extern BOOL HTAnchor_link (HTAnchor * source,
HTAnchor * destination,
HTLinkType type,
HTMethod method);
Find the Link Object that Binds two Anchors
If the destination anchor is a target of a link from the source anchor
then return the link object, else NULL.
extern HTLink * HTAnchor_findLink (HTAnchor *src, HTAnchor *dest);
Find destination with given relationship
Return the anchor with a given typed link.
extern HTAnchor * HTAnchor_followTypedLink (HTAnchor *me, HTLinkType type);
Handling the Main Link
Any outgoing link can at any time be the main destination.
extern BOOL HTAnchor_setMainLink (HTAnchor * anchor, HTLink * link);
extern HTLink * HTAnchor_mainLink (HTAnchor * anchor);
extern HTAnchor * HTAnchor_followMainLink (HTAnchor * anchor);
Handling the Sub Links
extern BOOL HTAnchor_setSubLinks (HTAnchor * anchor, HTList * list);
extern HTList * HTAnchor_subLinks (HTAnchor * anchor);
Move Link Information
Move all link information form one anchor to another. This is useful
when we get a redirection on a request and want to inherit the link
information to the new anchor and change the link information in the
old one to "redirect".
extern BOOL HTAnchor_moveAllLinks (HTAnchor *src, HTAnchor *dest);
Remove Link Information
Delete link information between two or more anchors
extern BOOL HTAnchor_removeLink (HTAnchor *src, HTAnchor *dest);
extern BOOL HTAnchor_removeAllLinks (HTAnchor * me);
Move a child anchor to the head of the list of its siblings
This is to ensure that an anchor which might have already existed is
put in the correct order as we load the document.
extern void HTAnchor_makeLastChild (HTChildAnchor *me);
Anchor Objects
We have three variants of the Anchor object - I guess some would call
them superclass and subclasses ;-)
Generic Anchor type
This is the super class of anchors. We often use this as an argument
to the functions that both accept parent anchors and child anchors. We
separate the first link from the others to avoid too many small
mallocs involved by a list creation. Most anchors only point to one
place.
Anchor for a Parent Object
These anchors points to the whole contents of a graphic object
(document). The parent anchor of a parent anchor is itself. The parent
anchor now contains all meta information about the object. This is
largely the entity headers in the HTTP specification.
Anchor for a Child Object
A child anchor is a anchor object that points to a subpart of a
graphic object (document)
Creation and Deletion Methods
After we have defined the data structures we must define the methods
that can be used on them. All anchors are kept in an internal hash
table so that they are easier to find again.
Find/Create a Parent Anchor
This one is for a reference (link) which is found in a document, and
might not be already loaded. The parent anchor returned can either be
created on the spot or is already in the hash table.
extern HTAnchor * HTAnchor_findAddress (CONST char * address);
Find/Create a Child Anchor
This one is for a new child anchor being edited into an existing
document. The parent anchor must already exist but the child returned
can either be created on the spot or is already in the hash table. The
tag is the part that's after the '#' sign in a URI.
extern HTChildAnchor * HTAnchor_findChild (HTParentAnchor *parent,
CONST char * tag);
Find/Create a Child Anchor and Link to Another Parent
Find a child anchor anchor with a given parent and possibly a
tag, and (if passed) link this child to the URI given in the
href. As we really want typed links to the caller should also
indicate what the type of the link is (see HTTP spec for more
information). The link is relative to the address of the
parent anchor.
extern HTChildAnchor * HTAnchor_findChildAndLink
(HTParentAnchor * parent, /* May not be 0 */
CONST char * tag, /* May be "" or 0 */
CONST char * href, /* May be "" or 0 */
HTLinkType ltype); /* May be 0 */
Delete an Anchor
All outgoing links from parent and children are deleted, and this
anchor is removed from the sources list of all its targets. We also
delete the targets. If this anchor's source list is empty, we delete
it and its children.
extern BOOL HTAnchor_delete (HTParentAnchor *me);
Delete all Anchors
Deletes all anchors and return a list of all the objects
(hyperdoc) hanging of the parent anchors found while doing it. The
application may keep its own list of HyperDoc
s, but this
function returns it anyway. It is always for the application
to delete any HyperDoc
s. If NULL then no hyperdocs are
returned. Return YES if OK, else NO.
Note: This function is different from cleaning up the history
list!
extern BOOL HTAnchor_deleteAll (HTList * objects);
Access Methods of an Anchor
These functions should be used to access information within the anchor
structures.
Relations to Other Anchors
Who is Parent?
For parent anchors this returns the anchor itself
extern HTParentAnchor * HTAnchor_parent (HTAnchor *me);
Does it have any Anchors within it?
extern BOOL HTAnchor_hasChildren (HTParentAnchor *me);
Binding a Data Object to an Anchor
A parent anchor can have a data object bound to it. This data object
does can for example be a parsed version of a HTML that knows how to
present itself to the user, or it can be an unparsed data object. It's
completely free for the application to use this possibility, but a
typical usage would to manage the data object as part of a memory
cache.
extern void HTAnchor_setDocument (HTParentAnchor *me, void * doc);
extern void * HTAnchor_document (HTParentAnchor *me);
URI Information of Anchors
There are two addresses of an anchor. The URI that was passed when the
anchor was crated and the physical address that's used when the URI is
going to be requested. The two addresses may be different if the
request is going through a proxy or a gateway.
Get URI Address
Returns the full URI of the anchor, child or parent as a malloc'd
string to be freed by the caller as when the anchor was created.
extern char * HTAnchor_address (HTAnchor *me);
Cache Information
If the cache manager finds a cached object, it is registered in the
anchor object. This way the file loader
knows that it is a MIME data object. The cache manager does not know
whether the data object is out of date (for example if a
Expires: header is in the MIME header. This is for the MIME parser to find out.
extern BOOL HTAnchor_cacheHit (HTParentAnchor *me);
extern void HTAnchor_setCacheHit (HTParentAnchor *me, BOOL cacheHit);
Physical address
Contains the physical address after we haved looked for proxies etc.
extern char * HTAnchor_physical (HTParentAnchor * me);
extern void HTAnchor_setPhysical (HTParentAnchor * me, char * protocol);
Is the Anchor searchable?
extern void HTAnchor_clearIndex (HTParentAnchor *me);
extern void HTAnchor_setIndex (HTParentAnchor *me);
extern BOOL HTAnchor_isIndex (HTParentAnchor *me);
Title handling
We keep the title in the anchor as we then can refer to it later in
the history list etc. We can also obtain the title element if it is
passed as a HTTP header in the response. Any title element found in an
HTML document will overwrite a title given in a HTTP header.
extern CONST char * HTAnchor_title (HTParentAnchor *me);
extern void HTAnchor_setTitle (HTParentAnchor *me,
CONST char * title);
extern void HTAnchor_appendTitle (HTParentAnchor *me,
CONST char * title);
Media Types (Content-Type)
extern HTFormat HTAnchor_format (HTParentAnchor *me);
extern void HTAnchor_setFormat (HTParentAnchor *me,
HTFormat form);
Charset parameter to Content-Type
extern HTCharset HTAnchor_charset (HTParentAnchor *me);
extern void HTAnchor_setCharset (HTParentAnchor *me,
HTCharset charset);
Level parameter to Content-Type
extern HTLevel HTAnchor_level (HTParentAnchor * me);
extern void HTAnchor_setLevel (HTParentAnchor * me,
HTLevel level);
Content Language
extern HTLanguage HTAnchor_language (HTParentAnchor *me);
extern void HTAnchor_setLanguage (HTParentAnchor *me,
HTLanguage language);
Content Encoding
extern HTEncoding HTAnchor_encoding (HTParentAnchor *me);
extern void HTAnchor_setEncoding (HTParentAnchor *me,
HTEncoding encoding);
Content Transfer Encoding
extern HTCte HTAnchor_cte (HTParentAnchor *me);
extern void HTAnchor_setCte (HTParentAnchor *me,
HTCte cte);
Content Length
extern long int HTAnchor_length (HTParentAnchor *me);
extern void HTAnchor_setLength (HTParentAnchor *me,
long int length);
Allowed methods (Allow)
extern int HTAnchor_methods (HTParentAnchor *me);
extern void HTAnchor_setMethods (HTParentAnchor *me,
int methodset);
extern void HTAnchor_appendMethods (HTParentAnchor *me,
int methodset);
Version
extern char * HTAnchor_version (HTParentAnchor * me);
extern void HTAnchor_setVersion (HTParentAnchor * me, CONST char * version);
Date
Returns the date that was registered in the RFC822 header "Date"
extern time_t HTAnchor_date (HTParentAnchor * me);
extern void HTAnchor_setDate (HTParentAnchor * me, CONST time_t date);
Last Modified Date
Returns the date that was registered in the RFC822 header "Last-Modified"
extern time_t HTAnchor_lastModified (HTParentAnchor * me);
extern void HTAnchor_setLastModified (HTParentAnchor * me, CONST time_t lm);
Expires Date
extern time_t HTAnchor_expires (HTParentAnchor * me);
extern void HTAnchor_setExpires (HTParentAnchor * me, CONST time_t exp);
Derived from
extern char * HTAnchor_derived (HTParentAnchor *me);
extern void HTAnchor_setDerived (HTParentAnchor *me, CONST char *derived_from);
Extra Headers
List of unknown headers coming in from the network. Do not use the
HTAnchor_addExtra()
function to extra headers here, but
use the field in the request structure
for sending test headers.
extern HTList * HTAnchor_Extra (HTParentAnchor *me);
extern void HTAnchor_addExtra (HTParentAnchor *me,
CONST char * header);
Status of Header Parsing
These are primarily for internal use
extern BOOL HTAnchor_headerParsed (HTParentAnchor *me);
extern void HTAnchor_setHeaderParsed (HTParentAnchor *me);
We want to clear the header information...
extern void HTAnchor_clearHeader (HTParentAnchor *me);
#endif /* HTANCHOR_H */