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28d440ab KL |
1 | -*- coding: utf-8; -*- |
2 | GOAL | |
3 | ---- | |
4 | ||
5 | The ultimate goal of this branch is to implement support for opening | |
6 | multiple, different tty devices and simultaneous X and tty frames from | |
7 | a single Emacs session. | |
8 | ||
9 | WHO IS DOING IT | |
10 | --------------- | |
11 | ||
12 | I'm Károly Lőrentey. My address: lorentey@elte.hu. | |
13 | ||
14 | Patches or suggestions are welcome! | |
15 | ||
6548cf00 | 16 | Retrieving the latest version of the branch: |
4f0359de KL |
17 | |
18 | tla register-archive lorentey@elte.hu--2004 http://lorentey.web.elte.hu/arch/2004/ | |
19 | tla get lorentey@elte.hu--2004/emacs--multi-tty--0 <directory> | |
20 | ||
21 | (I use tla 1.1.) | |
22 | ||
28d440ab KL |
23 | |
24 | STATUS | |
25 | ------ | |
26 | ||
52c2ee2a KL |
27 | Basic multi-tty support is there; there are some rough edges, but it |
28 | already seems to be usable. Emacsclient has been extended to support | |
29 | opening a new terminal frame. | |
28d440ab | 30 | |
04c3243c KL |
31 | To try it out, compile the multi-tty branch with the following |
32 | commands: | |
bc279d67 KL |
33 | |
34 | mkdir +build | |
35 | cd +build | |
36 | ../configure --with-x-toolkit=no --without-x | |
37 | make bootstrap | |
38 | ||
39 | then start up the emacs server (src/emacs, M-x server-start), and then | |
6548cf00 | 40 | (from a shell prompt on another terminal) start emacsclient with |
28d440ab | 41 | |
04c3243c | 42 | lib-src/emacsclient -h /optional/file/names... |
28d440ab | 43 | |
04c3243c KL |
44 | You'll hopefully have two fully working, independent frames on |
45 | separate terminals. (This seems to be very useful, emacsclient starts | |
46 | up even faster than vi!) :-) You can close the newly opened frame and | |
47 | return to the shell without exiting Emacs by pressing C-x 5 0, i.e., | |
48 | delete-frame. (Note that this does not seem to work yet on the | |
49 | original terminal.) Creating new frames on the same tty with C-x 5 2 | |
50 | works exactly as before. Suspending Emacs is disabled at the moment. | |
51 | If you exit emacs, all terminals should be restored to their previous | |
52 | states. | |
52c2ee2a KL |
53 | |
54 | X, Mac, Windows and DOS support is broken, probably doesn't even | |
04c3243c KL |
55 | compile -- this will be solved later. Please see the attached README |
56 | for other issues, implementation notes and sub-TODO items. | |
57 | ||
58 | Only tested on my GNU/Linux box. | |
6548cf00 | 59 | |
28d440ab KL |
60 | |
61 | NEWS | |
62 | ---- | |
63 | ||
64 | For the NEWS file: | |
65 | ||
66 | ** Support for multiple terminal devices has been added. You can | |
67 | specify a terminal device (`tty' parameter) and a terminal type | |
6548cf00 | 68 | (`tty-type' parameter) to `make-terminal-frame'. `tty' must be a |
52c2ee2a | 69 | terminal device created by the updated emacsclient, or there will |
0a125897 | 70 | be problems with terminal input and window resizes. |
6548cf00 KL |
71 | |
72 | You can test for the presence of multiple terminal support by | |
73 | testing for the `multi-tty' feature. | |
74 | ||
75 | ** A make-frame-on-tty function has been added to make it easier to | |
76 | create frames on new terminals. | |
28d440ab | 77 | |
9628b887 KL |
78 | ** Emacsclient has been extended to support opening a new terminal |
79 | frame. | |
28d440ab KL |
80 | |
81 | CHANGELOG | |
82 | --------- | |
83 | ||
84 | See arch logs. | |
85 | ||
86 | ||
6548cf00 KL |
87 | DIARY OF CHANGES |
88 | ---------------- | |
89 | ||
90 | (ex-TODO items with explanations.) | |
28d440ab KL |
91 | |
92 | -- Introduce a new abstraction for terminal devices. | |
93 | ||
94 | (Done, see struct tty_output. The abstraction is not yet | |
95 | complete.) | |
96 | ||
28d440ab KL |
97 | -- Change the bootstrap procedure to initialize tty_list. |
98 | ||
99 | (Done, but needs review.) | |
100 | ||
28d440ab KL |
101 | -- Change make-terminal-frame to support specifying another tty. |
102 | ||
103 | (Done, new frame parameters: `tty' and `tty-type'.) | |
104 | ||
9628b887 KL |
105 | -- Implement support for reading from multiple terminals. |
106 | ||
107 | (Done, read_avail_input tries to read from each terminal, until one | |
6548cf00 KL |
108 | succeeds. MULTIKBOARD is not used. Secondary terminals don't send |
109 | SIGIO!) | |
9628b887 KL |
110 | |
111 | -- other-frame should cycle through the frames on the `current' | |
6548cf00 | 112 | terminal only. |
9628b887 | 113 | |
6548cf00 | 114 | (Done, by trivially modifiying next_frame and prev_frame.) |
9628b887 KL |
115 | |
116 | -- Support different terminal sizes. | |
117 | ||
118 | (Done, no problem.) | |
119 | ||
120 | -- Make sure terminal resizes are handled gracefully. (Could be | |
121 | problematic.) | |
122 | ||
6548cf00 KL |
123 | (Done. We don't get automatic SIGWINCH for additional ttys, |
124 | though.) | |
9628b887 KL |
125 | |
126 | -- Extend emacsclient to automatically open a new tty when it connects | |
127 | to Emacs. | |
128 | ||
129 | (Done. It's an ugly hack, needs more work.) | |
130 | ||
52c2ee2a KL |
131 | -- Redisplay must refresh the topmost frame on *all* terminals, not |
132 | just the initial terminal. | |
9628b887 | 133 | |
52c2ee2a | 134 | (Done, but introduced an ugly redisplay problems. Ugh.) |
9628b887 | 135 | |
6548cf00 KL |
136 | -- Fix redisplay problems. |
137 | ||
52c2ee2a KL |
138 | (Done; it turned out that the entire Wcm structure must be moved |
139 | inside tty_output. Why didn't I catch this earlier?) | |
6548cf00 KL |
140 | |
141 | -- Provide a way for emacsclient to tell Emacs that the tty has been | |
142 | resized. | |
143 | ||
144 | (Done, simply forward the SIGWINCH signal.) | |
145 | ||
146 | -- Each keypress should automatically select the frame corresponding | |
147 | to the terminal that it was coming from. This means that Emacs | |
148 | must know from which terminal the last keyboard event came from. | |
6548cf00 | 149 | |
52c2ee2a KL |
150 | (Done, it was quite simple, the input event system already |
151 | supported multiple frames.) | |
6548cf00 KL |
152 | |
153 | -- Fix SIGIO issue with secondary terminals. | |
154 | ||
155 | (Done, emacsclient signals Emacs after writing to the proxy pseudo | |
52c2ee2a KL |
156 | terminal. Note that this means that multi-tty does not work with |
157 | raw ttys!) | |
28d440ab | 158 | |
0a125897 KL |
159 | (Update: This is bullshit. There is a read_input_waiting function, |
160 | extend that somehow.) | |
161 | ||
fca177d4 KL |
162 | -- Make make-terminal-frame look up the `tty' and `tty-type' frame |
163 | parameters from the currently selected terminal before the global | |
164 | default. | |
165 | ||
166 | (Done.) | |
167 | ||
168 | -- Put all cached terminal escape sequences into struct tty_output. | |
169 | Currently, they are still stored in global variables, so we don't | |
170 | really support multiple terminal types. | |
171 | ||
52c2ee2a | 172 | (Done. It was not fun.) |
fca177d4 KL |
173 | |
174 | -- Implement sane error handling after initialization. (Currently | |
6548cf00 KL |
175 | emacs exits if you specify a bad terminal type.) The helpful error |
176 | messages must still be provided when Emacs starts. | |
177 | ||
fca177d4 KL |
178 | (Done.) |
179 | ||
180 | -- Implement terminal deletion, i.e., deleting local frames, closing | |
181 | the tty device and restoring its previous state without exiting | |
182 | Emacs. | |
9628b887 | 183 | |
fca177d4 KL |
184 | (Done, but at the moment only called when an error happens during |
185 | initialization. There is a memory corruption error around this | |
186 | somewhere.) | |
187 | ||
8303ba32 KL |
188 | -- Implement automatic deletion of terminals when the last frame on |
189 | that terminal is closed. | |
190 | ||
191 | (Done.) | |
192 | ||
0a125897 KL |
193 | -- Restore tty screen after closing the terminal. |
194 | ||
195 | (Done, we do the same as Emacs 21.2 for all terminals.) | |
196 | ||
197 | -- 'TERM=dumb src/emacs' does not restore the terminal state. | |
198 | ||
199 | (Done.) | |
fca177d4 | 200 | |
b2af72d2 KL |
201 | -- C-g should work on secondary terminals. |
202 | ||
203 | (Done, but the binding is not configurable.) | |
204 | ||
205 | -- Deal with SIGHUP in Emacs and in emacsclient. (After this, the | |
206 | server-frames may be removed from server.el.) | |
207 | ||
208 | (Done, nothing to do. It seems that Emacs does not receive SIGHUP | |
209 | from secondary ttys.) | |
210 | ||
211 | -- Change emacsclient/server.el to support the -h argument better, | |
212 | i.e. automatically close the socket when the frame is closed. | |
213 | ||
214 | (Seems to be working OK.) | |
215 | ||
c1c63edb KL |
216 | -- Enable select on ttys (sys_select disables the native select on |
217 | non-X systems). There are some systems (OSS, SCO, maybe cygwin?) | |
218 | that don't support this, so make sure the emulation remains | |
219 | available for them. | |
220 | ||
221 | (This was a bogus issue, select is only #defined to be sys_select | |
222 | by sysselect.h if BROKEN_SELECT_NON_X. Fixed sysdep.c to compile | |
223 | sys_select only then.) | |
224 | ||
225 | ||
fca177d4 KL |
226 | THINGS TO DO |
227 | ------------ | |
228 | ||
c1c63edb KL |
229 | ** Understand Emacs's low-level input system. It seems |
230 | complicated. :-) | |
231 | ||
fca177d4 KL |
232 | ** Fix mysterious memory corruption error with tty deletion. To |
233 | trigger it, try the following shell command: | |
234 | ||
235 | while true; do TERM=no-such-terminal-definition emacsclient -h; done | |
236 | ||
237 | Emacs usually dumps core after a few dozen iterations. (The bug | |
238 | seems to be related to the xfree()ing or bzero()ing of | |
52c2ee2a KL |
239 | tty_output.Wcm or some other tty_output part. Maybe there are |
240 | outside references to struct Wcm? Why were these vars collected | |
241 | into a struct before multi-tty support?) | |
fca177d4 | 242 | |
52c2ee2a | 243 | The bug does not seem to happen if the error occurs before terminal |
fca177d4 | 244 | initialization or if I comment out all xfree()s in delete_frame. |
52c2ee2a KL |
245 | Update: yes it does, although it is much rarer. Or maybe it's |
246 | another bug. | |
fca177d4 | 247 | |
c1c63edb KL |
248 | Update: Some of these errors may have been caused by having more |
249 | file handles than FD_SETSIZE. | |
250 | ||
c33d2d42 | 251 | ** Find out why does Emacs abort when it wants to close its |
0a125897 KL |
252 | controlling tty. Hint: chan_process[] array. Hey, maybe |
253 | noninterrupt-IO would work, too? | |
c33d2d42 | 254 | |
0a125897 KL |
255 | ** Support raw secondary terminals. (Note that SIGIO works only on |
256 | the controlling terminal.) Hint: extend read_input_waiting() for | |
257 | multiple ttys and hopefully this will be fixed. | |
6548cf00 KL |
258 | |
259 | ** What does interrupt_input do? I tried to disable it for raw | |
52c2ee2a | 260 | secondary tty support, but it does not seem to do anything useful. |
6548cf00 | 261 | |
0a125897 KL |
262 | ** Issue with SIGIO: it needs to be disabled during redisplay. See if |
263 | fcntl() kernel behaviour could be emulated by emacsclient. | |
264 | ||
22de1e79 KL |
265 | ** Make parts of struct tty_output accessible from Lisp. The device |
266 | name and the type is sufficient. | |
267 | ||
268 | ** Export delete_tty to the Lisp environment, for emacsclient. | |
269 | ||
270 | ** Make sure C-g goes to the right frame. This is hard, as SIGINT | |
271 | doesn't have a tty parameter. :-( | |
272 | ||
273 | ** Implement support for starting an interactive Emacs session without | |
274 | an initial frame. (The user would connect to it and open frames | |
275 | later, with emacsclient.) Not necessarily a good idea. | |
276 | ||
52c2ee2a KL |
277 | ** Move optimalization parameters (costs) from union output_data to |
278 | a backend-neutral per-device structure. | |
28d440ab | 279 | |
c33d2d42 KL |
280 | ** Find out the best way to support suspending Emacs with multiple |
281 | ttys. | |
282 | ||
c1c63edb | 283 | ** Do tty output through term_hooks, like graphical display backends. |
6548cf00 | 284 | |
52c2ee2a KL |
285 | ** Fix X support. |
286 | ||
c1c63edb KL |
287 | ** Allow simultaneous X and tty frames. (Handling input could be |
288 | tricky.) | |
28d440ab KL |
289 | |
290 | ** Fix Mac support (I can't do this myself). | |
291 | ||
292 | ** Fix W32 support (I can't do this myself). | |
293 | ||
294 | ** Fix DOS support (I can't do this myself). | |
295 | ||
296 | ||
297 | ||
298 | ;;; arch-tag: 8da1619e-2e79-41a8-9ac9-a0485daad17d |