code review 89560044: acme: add put file in acme root directory

acme: add log file in acme root directory

Reading /mnt/acme/log reports a log of window create,
put, and delete events, as they happen. It blocks until the
next event is available.

Example log output:

8 new /Users/rsc/foo.go
8 put /Users/rsc/foo.go
8 del /Users/rsc/foo.go

This lets acme-aware programs react to file writes, for example
compiling code, running a test, or updating an import block.

[rsc, 2014-04-19 18:04:23]

Hello r,

I'd like you to review this change to
https://code.google.com/p/plan9port

[rsc, 2014-04-19 18:09:56]

I've been meaning to try something like this for a while. One idea is to make
'Watch' use it instead of file system notifications. Another is to have a
program you can run that waits for a .go file to be written and then uses Brad's
goimports program to decide if the import block needs to be updated and if so
edits the import block in the window body (so that the window becomes dirty
again and you can Undo/Redo to see what the change was and Put if you agree).
Another could be to do the same for gofmt, although I think I like unindented
debugging statements too much to use that.

[r, 2014-04-19 18:17:39]

i think there's a great idea here but i'm not certain this is quite it. my
concern is generality: you have a 'put' file but this notion will encourage me
tomorrow to want something else. your analogy with inotify is relevant here:
that's designed wrong by being too general (and os-specific, but ignore that);
maybe this is too specific. why writes, and only writes? (because it changes the
external state, sure, but is that sufficient justification?)

i'm thinking out loud here, but i believe you want something called 'log' not
put, tag the events with "put", and perhaps the ability to filter the events it
delivers through a regexp that you write to the file or some control file.

but i may be overdesigning

https://codereview.appspot.com/89560044/diff/40001/src/cmd/acme/buff.c
File src/cmd/acme/buff.c (right):

https://codereview.appspot.com/89560044/diff/40001/src/cmd/acme/buff.c#newcod...
src/cmd/acme/buff.c:285: abort();
undo this change?

[rsc, 2014-04-19 21:24:03]

https://codereview.appspot.com/89560044/diff/40001/src/cmd/acme/buff.c
File src/cmd/acme/buff.c (right):

https://codereview.appspot.com/89560044/diff/40001/src/cmd/acme/buff.c#newcod...
src/cmd/acme/buff.c:285: abort();
On 2014/04/19 18:17:39, r wrote:
> undo this change?

removed this file from the CL. (my acme dies every few weeks here and i just got
around to adding an abort to try to get a core file and therefore stack trace
when it happens.)

[rsc, 2014-04-19 21:26:10]

PTAL

Now there is a file named 'log' that reports window operations new, zerox, get,
put, del. The reporting of new is delayed in the source code for
internally-created windows until the name has been set. For externally created
windows this is not really possible, so 'new' log entries for external windows
give an empty name. One possible change would be to report the 'new' entry
without a name always and add a separate 'name' operation and report all window
name changes in winsetname.

[r, 2014-04-19 23:56:24]

please update CL description - it's from the previous round

the one thing i thought of in the interval isn't here, which is Edit commands

https://codereview.appspot.com/89560044/diff/60001/src/cmd/acme/xfid.c
File src/cmd/acme/xfid.c (right):

https://codereview.appspot.com/89560044/diff/60001/src/cmd/acme/xfid.c#newcod...
src/cmd/acme/xfid.c:1124: // State for global log file.
move this to logf.c

[rsc, 2014-04-28 20:11:07]

Hello r@golang.org,

Please take another look.

[r, 2014-04-28 20:57:04]

the CL still talks about put not log, but otherwise this is ok.
let's talk before you check this in though.

[rsc, 2014-04-30 16:14:33]

*** Submitted as
https://code.google.com/p/plan9port/source/detail?r=9e531f5eb3ab ***

acme: add log file in acme root directory

Reading /mnt/acme/log reports a log of window create,
put, and delete events, as they happen. It blocks until the
next event is available.

Example log output:

8 new /Users/rsc/foo.go
8 put /Users/rsc/foo.go
8 del /Users/rsc/foo.go

This lets acme-aware programs react to file writes, for example
compiling code, running a test, or updating an import block.

TBR=r
R=r
https://codereview.appspot.com/89560044