package Perinci::Sub::Util;
use 5.010001;
use strict;
use warnings;
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(
err
caller
gen_modified_sub
);
our $DATE = '2014-06-27'; # DATE
our $VERSION = '0.38'; # VERSION
our %SPEC;
our $STACK_TRACE;
our @_c; # to store temporary celler() result
our $_i; # temporary variable
sub err {
require Scalar::Util;
# get information about caller
my @caller = CORE::caller(1);
if (!@caller) {
# probably called from command-line (-e)
@caller = ("main", "-e", 1, "program");
}
my ($status, $msg, $meta, $prev);
for (@_) {
my $ref = ref($_);
if ($ref eq 'ARRAY') { $prev = $_ }
elsif ($ref eq 'HASH') { $meta = $_ }
elsif (!$ref) {
if (Scalar::Util::looks_like_number($_)) {
$status = $_;
} else {
$msg = $_;
}
}
}
$status //= 500;
$msg //= "$caller[3] failed";
$meta //= {};
$meta->{prev} //= $prev if $prev;
# put information on who produced this error and where/when
if (!$meta->{logs}) {
# should we produce a stack trace?
my $stack_trace;
{
no warnings;
# we use Carp::Always as a sign that user wants stack traces
last unless $STACK_TRACE // $INC{"Carp/Always.pm"};
# stack trace is already there in previous result's log
last if $prev && ref($prev->[3]) eq 'HASH' &&
ref($prev->[3]{logs}) eq 'ARRAY' &&
ref($prev->[3]{logs}[0]) eq 'HASH' &&
$prev->[3]{logs}[0]{stack_trace};
$stack_trace = [];
$_i = 1;
while (1) {
{
package DB;
@_c = CORE::caller($_i);
if (@_c) {
$_c[4] = [@DB::args];
}
}
last unless @_c;
push @$stack_trace, [@_c];
$_i++;
}
}
push @{ $meta->{logs} }, {
type => 'create',
time => time(),
package => $caller[0],
file => $caller[1],
line => $caller[2],
func => $caller[3],
( stack_trace => $stack_trace ) x !!$stack_trace,
};
}
#die;
[$status, $msg, undef, $meta];
}
sub caller {
my $n0 = shift;
my $n = $n0 // 0;
my $pkg = $Perinci::Sub::Wrapper::default_wrapped_package //
'Perinci::Sub::Wrapped';
my @r;
my $i = 0;
my $j = -1;
while ($i <= $n+1) { # +1 for this sub itself
$j++;
@r = CORE::caller($j);
last unless @r;
if ($r[0] eq $pkg && $r[1] =~ /^\(eval /) {
next;
}
$i++;
}
return unless @r;
return defined($n0) ? @r : $r[0];
}
$SPEC{gen_modified_sub} = {
v => 1.1,
summary => 'Generate modified metadata (and subroutine) based on another',
description => <<'_',
Often you'll want to create another sub (and its metadata) based on another, but
with some modifications, e.g. add/remove/rename some arguments, change summary,
add/remove some properties, and so on.
Instead of cloning the Rinci metadata and modify it manually yourself, this
routine provides some shortcuts.
You can specify base sub/metadata using `base_name` (string, subroutine name,
either qualified or not) or `base_code` (coderef) + `base_meta` (hash).
_
args => {
base_name => {
summary => 'Subroutine name (either qualified or not)',
schema => 'str*',
description => <<'_',
If not qualified with package name, will be searched in the caller's package.
Rinci metadata will be searched in `%SPEC` package variable.
Alternatively, you can also specify `base_code` and `base_meta`.
_
},
base_code => {
summary => 'Base subroutine code',
schema => 'code*',
description => <<'_',
If you specify this, you'll also need to specify `base_meta`.
Alternatively, you can specify `base_name` instead, to let this routine search
the base subroutine from existing Perl package.
_
},
base_meta => {
summary => 'Base Rinci metadata',
schema => 'hash*', # XXX defhash/rifunc
},
output_name => {
summary => 'Where to install the modified sub',
schema => 'str*',
description => <<'_',
Subroutine will be put in the specified name. If the name is not qualified with
package name, will use caller's package. If no `output_code` is specified, the
base subroutine reference will be assigned here.
Note that this argument is optional.
_
},
summary => {
summary => 'Summary for the mod subroutine',
schema => 'str*',
},
description => {
summary => 'Description for the mod subroutine',
schema => 'str*',
},
remove_args => {
summary => 'List of arguments to remove',
schema => 'array*',
},
add_args => {
summary => 'Arguments to add',
schema => 'hash*',
},
replace_args => {
summary => 'Arguments to add',
schema => 'hash*',
},
rename_args => {
summary => 'Arguments to rename',
schema => 'hash*',
},
modify_args => {
summary => 'Arguments to modify',
description => <<'_',
For each argument you can specify a coderef. The coderef will receive the
argument ($arg_spec) and is expected to modify the argument specification.
_
schema => 'hash*',
},
modify_meta => {
summary => 'Specify code to modify metadata',
schema => 'code*',
description => <<'_',
Code will be called with arguments ($meta) where $meta is the cloned Rinci
metadata.
_
},
install_sub => {
schema => 'bool',
default => 1,
},
},
result => {
schema => ['hash*' => {
keys => {
code => ['code*'],
meta => ['hash*'], # XXX defhash/risub
},
}],
},
};
sub gen_modified_sub {
require Function::Fallback::CoreOrPP;
my %args = @_;
# get base code/meta
my ($base_code, $base_meta);
if ($args{base_name}) {
my ($pkg, $leaf);
if ($args{base_name} =~ /(.+)::(.+)/) {
($pkg, $leaf) = ($1, $2);
} else {
$pkg = CORE::caller();
$leaf = $args{base_name};
}
no strict 'refs';
$base_code = \&{"$pkg\::$leaf"};
$base_meta = ${"$pkg\::SPEC"}{$leaf};
die "Can't find Rinci metadata for $pkg\::$leaf" unless $base_meta;
} elsif ($args{base_meta}) {
$base_meta = $args{base_meta};
$base_code = $args{base_code}
or die "Please specify base_code";
} else {
die "Please specify base_name or base_code+base_meta";
}
my $output_meta = Function::Fallback::CoreOrPP::clone($base_meta);
my $output_code = $args{output_code} // $base_code;
# modify metadata
for (qw/summary description/) {
$output_meta->{$_} = $args{$_} if $args{$_};
}
if ($args{remove_args}) {
delete $output_meta->{args}{$_} for @{ $args{remove_args} };
}
if ($args{add_args}) {
for my $k (keys %{ $args{add_args} }) {
my $v = $args{add_args}{$k};
die "Can't add arg '$k' in mod sub: already exists"
if $output_meta->{args}{$k};
$output_meta->{args}{$k} = $v;
}
}
if ($args{replace_args}) {
for my $k (keys %{ $args{replace_args} }) {
my $v = $args{replace_args}{$k};
die "Can't replace arg '$k' in mod sub: doesn't exist"
unless $output_meta->{args}{$k};
$output_meta->{args}{$k} = $v;
}
}
if ($args{rename_args}) {
for my $old (keys %{ $args{rename_args} }) {
my $new = $args{rename_args}{$old};
my $as = $output_meta->{args}{$old};
die "Can't rename arg '$old' in mod sub: doesn't exist" unless $as;
die "Can't rename arg '$old'->'$new' in mod sub: ".
"new name already exist" if $output_meta->{args}{$new};
$output_meta->{args}{$new} = $as;
delete $output_meta->{args}{$old};
}
}
if ($args{modify_args}) {
for (keys %{ $args{modify_args} }) {
$args{modify_args}{$_}->($output_meta->{args}{$_});
}
}
if ($args{modify_meta}) {
$args{modify_meta}->($output_meta);
}
# install
if ($args{output_name}) {
my ($pkg, $leaf);
if ($args{output_name} =~ /(.+)::(.+)/) {
($pkg, $leaf) = ($1, $2);
} else {
$pkg = CORE::caller();
$leaf = $args{output_name};
}
no strict 'refs';
no warnings 'redefine';
*{"$pkg\::$leaf"} = $output_code if $args{install_sub} // 1;
${"$pkg\::SPEC"}{$leaf} = $output_meta;
}
[200, "OK", {code=>$output_code, meta=>$output_meta}];
}
1;
# ABSTRACT: Helper when writing functions
__END__
=pod
=encoding UTF-8
=head1 NAME
Perinci::Sub::Util - Helper when writing functions
=head1 VERSION
This document describes version 0.38 of Perinci::Sub::Util (from Perl distribution Perinci-Sub-Util), released on 2014-06-27.
=head1 SYNOPSIS
Example for err() and caller():
use Perinci::Sub::Util qw(err caller);
sub foo {
my %args = @_;
my $res;
my $caller = caller();
$res = bar(...);
return err($err, 500, "Can't foo") if $res->[0] != 200;
[200, "OK"];
}
Example for gen_modified_sub()
=head1 FUNCTIONS
=head2 caller([ $n ])
Just like Perl's builtin caller(), except that this one will ignore wrapper code
in the call stack. You should use this if your code is potentially wrapped. See
L<Perinci::Sub::Wrapper> for more details.
=head2 err(...) => ARRAY
Experimental.
Generate an enveloped error response (see L<Rinci::function>). Can accept
arguments in an unordered fashion, by utilizing the fact that status codes are
always integers, messages are strings, result metadata are hashes, and previous
error responses are arrays. Error responses also seldom contain actual result.
Status code defaults to 500, status message will default to "FUNC failed". This
function will also fill the information in the C<logs> result metadata.
Examples:
err(); # => [500, "FUNC failed", undef, {...}];
err(404); # => [404, "FUNC failed", undef, {...}];
err(404, "Not found"); # => [404, "Not found", ...]
err("Not found", 404); # => [404, "Not found", ...]; # order doesn't matter
err([404, "Prev error"]); # => [500, "FUNC failed", undef,
# {logs=>[...], prev=>[404, "Prev error"]}]
Will put C<stack_trace> in logs only if C<Carp::Always> module is loaded.
=head2 gen_modified_sub(%args) -> [status, msg, result, meta]
Generate modified metadata (and subroutine) based on another.
Often you'll want to create another sub (and its metadata) based on another, but
with some modifications, e.g. add/remove/rename some arguments, change summary,
add/remove some properties, and so on.
Instead of cloning the Rinci metadata and modify it manually yourself, this
routine provides some shortcuts.
You can specify base sub/metadata using C<base_name> (string, subroutine name,
either qualified or not) or C<base_code> (coderef) + C<base_meta> (hash).
Arguments ('*' denotes required arguments):
=over 4
=item * B<add_args> => I<hash>
Arguments to add.
=item * B<base_code> => I<code>
Base subroutine code.
If you specify this, you'll also need to specify C<base_meta>.
Alternatively, you can specify C<base_name> instead, to let this routine search
the base subroutine from existing Perl package.
=item * B<base_meta> => I<hash>
Base Rinci metadata.
=item * B<base_name> => I<str>
Subroutine name (either qualified or not).
If not qualified with package name, will be searched in the caller's package.
Rinci metadata will be searched in C<%SPEC> package variable.
Alternatively, you can also specify C<base_code> and C<base_meta>.
=item * B<description> => I<str>
Description for the mod subroutine.
=item * B<install_sub> => I<bool> (default: 1)
=item * B<modify_args> => I<hash>
Arguments to modify.
For each argument you can specify a coderef. The coderef will receive the
argument ($arg_spec) and is expected to modify the argument specification.
=item * B<modify_meta> => I<code>
Specify code to modify metadata.
Code will be called with arguments ($meta) where $meta is the cloned Rinci
metadata.
=item * B<output_name> => I<str>
Where to install the modified sub.
Subroutine will be put in the specified name. If the name is not qualified with
package name, will use caller's package. If no C<output_code> is specified, the
base subroutine reference will be assigned here.
Note that this argument is optional.
=item * B<remove_args> => I<array>
List of arguments to remove.
=item * B<rename_args> => I<hash>
Arguments to rename.
=item * B<replace_args> => I<hash>
Arguments to add.
=item * B<summary> => I<str>
Summary for the mod subroutine.
=back
Return value:
Returns an enveloped result (an array).
First element (status) is an integer containing HTTP status code
(200 means OK, 4xx caller error, 5xx function error). Second element
(msg) is a string containing error message, or 'OK' if status is
200. Third element (result) is optional, the actual result. Fourth
element (meta) is called result metadata and is optional, a hash
that contains extra information.
=head1 FAQ
=head2 What if I want to put result ($res->[2]) into my result with err()?
You can do something like this:
my $err = err(...) if ERROR_CONDITION;
$err->[2] = SOME_RESULT;
return $err;
=head1 TODO
L<Perinci::Sub::Wrapper> will generate wrapper that modifies caller() for the
wrapped subroutine (like in L<Hook::LexWrap>), so this module's caller() will
not be needed in the future.
=head1 SEE ALSO
L<Perinci>
=head1 HOMEPAGE
Please visit the project's homepage at L<https://metacpan.org/release/Perinci-Sub-Util>.
=head1 SOURCE
Source repository is at L<https://github.com/sharyanto/perl-Perinci-Sub-Util>.
=head1 BUGS
Please report any bugs or feature requests on the bugtracker website L<https://rt.cpan.org/Public/Dist/Display.html?Name=Perinci-Sub-Util>
When submitting a bug or request, please include a test-file or a
patch to an existing test-file that illustrates the bug or desired
feature.
=head1 AUTHOR
Steven Haryanto <stevenharyanto@gmail.com>
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2014 by Steven Haryanto.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut