view man/lispref/dragndrop.texi @ 5146:88bd4f3ef8e4

make lrecord UID's have a separate UID space for each object, resurrect debug SOE code in extents.c -------------------- ChangeLog entries follow: -------------------- src/ChangeLog addition: 2010-03-15 Ben Wing <ben@xemacs.org> * alloc.c: * alloc.c (c_readonly): * alloc.c (deadbeef_memory): * alloc.c (make_compiled_function): * alloc.c (make_button_data): * alloc.c (make_motion_data): * alloc.c (make_process_data): * alloc.c (make_timeout_data): * alloc.c (make_magic_data): * alloc.c (make_magic_eval_data): * alloc.c (make_eval_data): * alloc.c (make_misc_user_data): * alloc.c (noseeum_make_marker): * alloc.c (ADDITIONAL_FREE_string): * alloc.c (common_init_alloc_early): * alloc.c (init_alloc_once_early): * bytecode.c (print_compiled_function): * bytecode.c (mark_compiled_function): * casetab.c: * casetab.c (print_case_table): * console.c: * console.c (print_console): * database.c (print_database): * database.c (finalize_database): * device-msw.c (sync_printer_with_devmode): * device-msw.c (print_devmode): * device-msw.c (finalize_devmode): * device.c: * device.c (print_device): * elhash.c: * elhash.c (print_hash_table): * eval.c (print_multiple_value): * eval.c (mark_multiple_value): * events.c (deinitialize_event): * events.c (print_event): * events.c (event_equal): * extents.c: * extents.c (soe_dump): * extents.c (soe_insert): * extents.c (soe_delete): * extents.c (soe_move): * extents.c (extent_fragment_update): * extents.c (print_extent_1): * extents.c (print_extent): * extents.c (vars_of_extents): * frame.c: * frame.c (print_frame): * free-hook.c: * free-hook.c (check_free): * glyphs.c: * glyphs.c (print_image_instance): * glyphs.c (print_glyph): * gui.c: * gui.c (copy_gui_item): * hash.c: * hash.c (NULL_ENTRY): * hash.c (KEYS_DIFFER_P): * keymap.c (print_keymap): * keymap.c (MARKED_SLOT): * lisp.h: * lrecord.h: * lrecord.h (LISP_OBJECT_UID): * lrecord.h (set_lheader_implementation): * lrecord.h (struct old_lcrecord_header): * lstream.c (print_lstream): * lstream.c (finalize_lstream): * marker.c (print_marker): * marker.c (marker_equal): * mc-alloc.c (visit_all_used_page_headers): * mule-charset.c: * mule-charset.c (print_charset): * objects.c (print_color_instance): * objects.c (print_font_instance): * objects.c (finalize_font_instance): * opaque.c (print_opaque): * opaque.c (print_opaque_ptr): * opaque.c (equal_opaque_ptr): * print.c (internal_object_printer): * print.c (enum printing_badness): * rangetab.c (print_range_table): * rangetab.c (range_table_equal): * specifier.c (print_specifier): * specifier.c (finalize_specifier): * symbols.c: * symbols.c (print_symbol_value_magic): * tooltalk.c: * tooltalk.c (print_tooltalk_message): * tooltalk.c (print_tooltalk_pattern): * window.c (print_window): * window.c (debug_print_window): (1) Make lrecord UID's have a separate UID space for each object. Otherwise, with 20-bit UID's, we rapidly wrap around, especially when common objects like conses and strings increment the UID value for every object created. (Originally I tried making two UID spaces, one for objects that always print readably and hence don't display the UID, and one for other objects. But certain objects like markers for which a UID is displayed are still generated rapidly enough that UID overflow is a serious issue.) This also has the advantage of making UID values smaller, hence easier to remember -- their main purpose is to make it easier to keep track of different objects of the same type when debugging code. Make sure we dump lrecord UID's so that we don't have problems with pdumped and non-dumped objects having the same UID. (2) Display UID's consistently whenever an object (a) doesn't consistently print readably (objects like cons and string, which always print readably, can't display a UID), and (b) doesn't otherwise have a unique property that makes objects of a particular type distinguishable. (E.g. buffers didn't and still don't print an ID, but the buffer name uniquely identifies the buffer.) Some types, such as event, extent, compiled-function, didn't always (or didn't ever) display an ID; others (such as marker, extent, lstream, opaque, opaque-ptr, any object using internal_object_printer()) used to display the actual machine pointer instead. (3) Rename NORMAL_LISP_OBJECT_UID to LISP_OBJECT_UID; make it work over all Lisp objects and take a Lisp object, not a struct pointer. (4) Some misc cleanups in alloc.c, elhash.c. (5) Change code in events.c that "deinitializes" an event so that it doesn't increment the event UID counter in the process. Also use deadbeef_memory() to overwrite memory instead of doing the same with custom code. In the process, make deadbeef_memory() in alloc.c always available, and delete extraneous copy in mc-alloc.c. Also capitalize all uses of 0xDEADBEEF. Similarly in elhash.c call deadbeef_memory(). (6) Resurrect "debug SOE" code in extents.c. Make it conditional on DEBUG_XEMACS and on a `debug-soe' variable, rather than on SOE_DEBUG. Make it output to stderr, not stdout. (7) Delete some custom print methods that were identical to external_object_printer().
author Ben Wing <ben@xemacs.org>
date Mon, 15 Mar 2010 16:35:38 -0500
parents bc4f2511bbea
children
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@c -*-texinfo-*-
@c This is part of the XEmacs Lisp Reference Manual.
@c Copyright (C) 1998 Oliver Graf <ograf@fga.de>
@c Original reference is (c) 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
@c See the file lispref.texi for copying conditions.
@setfilename ../../info/dragndrop.texi
@node Drag and Drop, Modes, Scrollbars, Top
@chapter Drag and Drop
@cindex drag and drop

@emph{WARNING}: the Drag'n'Drop API is still under development and the
interface may change! The current implementation is considered experimental.

  Drag'n'drop is a way to transfer information between multiple applications.
To do this several GUIs define their own protocols. Examples are CDE, Motif,
KDE, MSWindows, GNOME, and many more. To catch all these protocols, XEmacs
provides a generic API.

One prime idea behind the API is to use a data interface that is
transparent for all systems. The author thinks that this is best
archived by using URL and MIME data, cause any internet enabled system
must support these for email already. XEmacs also already provides
powerful interfaces to support these types of data (tm and w3).

@menu
* Supported Protocols:: Which low-level protocols are supported.
* Drop Interface::      How XEmacs handles a drop from another application.
* Drag Interface::      Calls to initiate a drag from XEmacs.
@end menu

@node Supported Protocols
@section Supported Protocols

The current release of XEmacs only support a small set of Drag'n'drop
protocols. Some of these only support limited options available in the API.

@menu
* CDE dt::              Common Desktop Environment used on suns.
* MSWindows OLE::       Mr. Gates way of live.
* Loose ends::          The other protocols.
@end menu

@node CDE dt
@subsection CDE dt
@cindex CDE dt

CDE stands for Common Desktop Environment. It is based on the Motif
widget library. It's drag'n'drop protocol is also an abstraction of the
Motif protocol (so it might be possible, that XEmacs will also support
the Motif protocol soon).

CDE has three different types: file, buffer, and text. XEmacs only uses
file and buffer drags. The API will disallow full URL drags, only file
method URLs are passed through.

Buffer drags are always converted to plain text.

@node MSWindows OLE
@subsection MSWindows OLE
@cindex MSWindows OLE

Only allows file drags and drops.

@node Loose ends
@subsection Loose ends

The following protocols will be supported soon: Xdnd, Motif, Xde (if I
get some specs).

In particular Xdnd will be one of the protocols that can benefit from
the XEmacs API, cause it also uses MIME types to encode dragged data.

@node Drop Interface
@section Drop Interface
@cindex drop
@cindex Drop API

For each activated low-level protocol, an internal routine will catch
incoming drops and convert them to a dragdrop-drop type
misc-user-event.

This misc-user-event has its function argument set to
@code{dragdrop-drop-dispatch} and the object contains the data of the drop
(converted to URL/MIME specific data). This function will search the variable
@code{experimental-dragdrop-drop-functions} for a function that can handle the
dropped data.

To modify the drop behavior, the user can modify the variable
@code{experimental-dragdrop-drop-functions}. Each element of this list
specifies a possible handler for dropped data. The first one that can handle
the data will return @code{t} and exit. Another possibility is to set a
extent-property with the same name. Extents are checked prior to the
variable.

The customization group @code{drag-n-drop} shows all variables of user
interest.

@node Drag Interface
@section Drag Interface
@cindex drag
@cindex Drag API

This describes the drag API (not implemented yet).