avpops: avp_subst() support pvar as subst parameter

[linuxmaniac]

Pre-Submission Checklist

• Commit message has the format required by CONTRIBUTING guide
• Commits are split per component (core, individual modules, libs, utils, ...)
• Each component has a single commit (if not, squash them into one commit)
• No commits to README files for modules (changes must be done to docbook files
  in doc/ subfolder, the README file is autogenerated)

Type Of Change

• Small bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would change existing functionality)

Checklist:

• PR should be backported to stable branches
• Tested changes locally

Description

Allow pvar as second parameter of avp_subst() function

[miconda]

Looking further at this patch, it requires to have the second parameter as a single variable to be considered with "pvar" support, because I see you search for / in the second parameter. It makes it support like:

$var(se) = "/abc/xyz/";
avp_subst("$avp(x)", "$var(se)");

Right now it supports PV in the replacement part of the subst expression, not allowing in the match/regexp part.

Maybe is better to just add a new function that will always evaluate the subst parameter with variables, allowing more flexible format for subst parameter. At the end, you just need to have your added code in a dedicated function that evaluates first the parameter and then compiles the subst expression.

So we can have:

avp_susbtx("$avp(x)", "/$fU/$rU/g");

Allowing also:

$var(se) = "/" + $fU + "/" + $rU + "/g";
avp_substx("$avp(x)", "$var(se)");

The new function can have a different name than avp_substx(), I used to exemplify here.

[linuxmaniac]

Added avp_subst_pv() and now this is supported:

    $(avp(src)[*]) = "testME";
    $var(x) = "/e/j/gi";
    avp_subst_pv("$avp(src)", "$var(x)");

    $var(z) = "j";
    $var(y) = "e";
    $var(x) = "/" + $var(y) + "/" + $var(z) + "/gi";
    avp_subst_pv("$avp(src)", "$var(x)");
    avp_subst_pv("$avp(src)", "/$var(y)/$var(z)/gi");
    avp_subst_pv("$avp(src)", "/" + $var(y) + "/" + $var(z) + "/gi");
    avp_subst_pv("$avp(src)", "/e/j/gi");

[henningw]

Is this is still work in progress or could be merged?

[linuxmaniac]

I'm waiting for feedback. No more changes from my side.

[miconda]

It is a new function now, it can be merged.