Directory-age?!?
lazarus / 32-Linux

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cdbc · 2024-12-06 15:49

Hi
In my 'PluginMgr', I'm trying to detect changes in the "plugin-
directory", i.e.: if someone added a new plugin...
If my manager is running in mode 'ActiveOnly', it learns what plugins
are actually used and loads only them, cutting the load-times to ~1/10
But I'd like it to automagically detect /new-arrivals/ and reset
'active-cache' and load all plugins to let the user use the new plugin
...and then start learning anew...
So I'm fiddling with code like this, to ascertain if the directory has
been modified:Code: Pascal  [Select][+][-]window.onload =
function(){var x1 = document.getElementById("main_content_section");
if (x1) { var x = document.getElementsByClassName("geshi");for (var i
= 0; i program gda;  /// (g)et (d)irectory (a)ge /// {$mode
objfpc}{$H+} uses  {$IFDEF UNIX}  cthreads, baseunix,  {$ENDIF} 
Classes,sysutils; function DirAge(const FileName : rawbytestring; out
aStat: stat): ptrint;var  Info : baseunix.stat;  SystemFileName:
RawByteString;begin  SystemFileName:=
ToSingleByteFileSystemEncodedFileName(FileName);   if
 fpstat(PAnsiChar(SystemFileName),Info) < 0 then    exit(-1)  else   
Result:= Info.st_mtime; /// we're mostly interested in 'modified' 
aStat:= Info; /// record copy, but can't use pointer, 'cause info is
local and goes outta scopeend; var  da: ptrint;  dn: string;  st:
baseunix.stat; begin  writeln('>> (g)et (d)irectory (a)ge <<'); 
writeln('(i) usage: gda <directory-name>');  if ParamCount < 1 then
halt(1);  dn:= ParamStr(1);  da:= DirAge(dn,st);  writeln('>- - - -[
Info about "',dn,'" ]- - - -<');  writeln('(i) Dir-Mod: ',da,', as
DateTime: ',DateTimeToStr(FileDateToDateTime(da)));  writeln('(i) Dir-
Cre: ',st.st_ctime,', as DateTime:
',DateTimeToStr(FileDateToDateTime(st.st_ctime)));  writeln('(i) Dir-
Acc: ',st.st_atime,', as DateTime:
',DateTimeToStr(FileDateToDateTime(st.st_atime))); 
writeln('________________________________________');end.  'DirAge' is
a modified version of 'FileAge' in the RTL and I'm wondering if there
are some snags ahead that I can't foresee, since it's not in the
RTL?!?
I'll be happy for any input... 
Regards Benny
edit: typo

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MarkMLl · 2024-12-06 16:01

You need to use FAM. The details will vary a bit depending on OS but
see for example the attached.

MarkMLl

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cdbc · 2024-12-06 16:12

Thanks Mark, will have a LookSee 
Regards Benny

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MarkMLl · 2024-12-06 16:30

Look at the handful of functions near the end. That's from a program
that listens for the output from a logic analyzer in various forms,
and disassembles it. So I'm fairly confident that it gets tricky
things like the precise format of paths right.

MarkMLl

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cdbc · 2024-12-06 16:45

Hi
Cool code Mark, thanks.
So, inotify is a kernel-thingy, where you can get a /watched/ handle
to the object in question, got it.
I have to poll this handle regularly to get a heads up on said object.
...and I guess 'fpClose(handle);' when I'm done, to release inotify-
resources.
Am I right in thinking polling -> Thread? It so happens, I've got this
sleeping thread, that I can utilize whenever I want   It's actually
used to load plugins on app-startup and I just kept it around just in
case...

Am I understanding this correctly?!? 
Regards Benny

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MarkMLl · 2024-12-06 17:08

Yes, sounds about right.

MarkMLl

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cdbc · 2024-12-06 17:17

Hi
Thanks Mate 
Regards Benny

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MarkMLl · 2024-12-06 17:40

I find I've used that stuff in a couple more places, but not-
interestingly- in the program I was tweaking a few weeks ago which
reads the content of a DSO (digital 'scope) and can reload the backend
dynamic library if it's recompiled.

Updated: I've grafted it into the DSO program so that it re-reads the
directory containing the backends (each of which has the ISO date and
time in its name) only when something's actually changed. The API
doesn't, unfortunately, allow wildcards, but the more difficult part
of the exercise was working out the structure of my original code (a
reload can be triggered by a number of things, including HUP etc.).

MarkMLl