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DevIo.pm: DevIo_SimpleReadWithTimeout and DevIo_Expect from Boris

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git-svn-id: https://svn.fhem.de/fhem/trunk@5236 2b470e98-0d58-463d-a4d8-8e2adae1ed80
This commit is contained in:
rudolfkoenig 2014-03-16 16:13:14 +00:00
parent fdb28cbdf3
commit 7f4bc2024a
1 changed files with 70 additions and 6 deletions
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76
fhem/FHEM/DevIo.pm
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@ -2,13 +2,15 @@
# $Id$
package main;
sub DevIo_SimpleRead($);
sub DevIo_TimeoutRead($$);
sub DevIo_SimpleWrite($$$);
sub DevIo_OpenDev($$$);
sub DevIo_CloseDev($@);
sub DevIo_Disconnected($);
sub DevIo_Expect($$$);
sub DevIo_OpenDev($$$);
sub DevIo_SetHwHandshake($);
sub DevIo_SimpleRead($);
sub DevIo_SimpleReadWithTimeout($$);
sub DevIo_SimpleWrite($$$);
sub DevIo_TimeoutRead($$);
########################
sub
@ -53,7 +55,25 @@ DevIo_SimpleRead($)
}
########################
# Read until you get the timeout. Use it with care
# wait at most timeout seconds until the file handle gets ready
# for reading; returns undef on timeout
# NOTE1: FHEM can be blocked for $timeout seconds!
# NOTE2: This works on Windows only for TCP connections
sub
DevIo_SimpleReadWithTimeout($$)
{
my ($hash, $timeout) = @_;
my $rin = "";
vec($rin, $hash->{FD}, 1) = 1;
my $nfound = select($rin, undef, undef, $timeout);
return DevIo_DoSimpleRead($hash) if($nfound> 0);
return undef;
}
########################
# Read until you get the timeout. Use it with care since it waits _at least_
# timeout seconds, and it works on Windows only for TCP/IP connections
sub
DevIo_TimeoutRead($$)
{
@ -72,7 +92,6 @@ DevIo_TimeoutRead($$)
return $answer;
}
########################
# Input is HEX, with header and CRC
sub
@ -91,6 +110,51 @@ DevIo_SimpleWrite($$$)
select(undef, undef, undef, 0.001);
}
########################
# Write something, then read something
# reopen device if timeout occurs and write again, then read again
sub
DevIo_Expect($$$)
{
my ($hash, $msg, $timeout) = @_;
my $name= $hash->{NAME};
my $state= $hash->{STATE};
if($state ne "opened") {
Log3 $name, 2, "Attempt to write to $state device.";
return undef;
}
# write something
return undef unless defined(DevIo_SimpleWrite($hash, $msg, 0));
# read answer
my $answer= DevIo_SimpleReadWithTimeout($hash, $timeout);
return $answer unless($answer eq "");
# the device has failed to deliver a result
$hash->{STATE}= "failed";
DoTrigger($name, "FAILED");
# reopen device
# unclear how to know whether the following succeeded
Log3 $name, 2, "$name: first attempt to read timed out, trying to close and open the device.";
# The next two lines are required to avoid a deadlock when the remote end closes the connection
# upon DevIo_OpenDev, as e.g. netcat -l <port> does.
DevIo_CloseDev($hash);
sleep(5) if($hash->{USBDEV});
DevIo_OpenDev($hash, 0, undef); # where to get the initfn from?
# write something again
return undef unless defined(DevIo_SimpleWrite($hash, $msg, 0));
# read answer again
$answer= DevIo_SimpleReadWithTimeout($hash, $timeout);
# success
if($answer ne "") {
$hash->{STATE}= "opened";
DoTrigger($name, "CONNECTED");
return $answer;
}
# ultimate failure
Log3 $name, 2, "$name: second attempt to read timed out, this is an unrecoverable error.";
DoTrigger($name, "DISCONNECTED");
return undef; # undef means ultimate failure
}
########################
sub