/usr/share/perl5/Eval/Context.pm is in libeval-context-perl 0.09.11-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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use strict;
use warnings ;
BEGIN
{
use vars qw ($VERSION);
$VERSION = '0.09' ;
}
#-------------------------------------------------------------------------------
use English qw( -no_match_vars ) ;
use Readonly ;
Readonly my $EMPTY_STRING => q{} ;
Readonly our $SHARED => 0 ;
Readonly our $PERSISTENT => 1 ;
my $flag ;
Readonly our $USE => bless \$flag, 'USE_PERSISTENT' ;
use Carp qw(carp croak confess) ;
use File::Slurp ;
use Sub::Install qw(install_sub reinstall_sub) ;
use Symbol qw(delete_package);
use Safe ;
use Data::Dumper ;
#-------------------------------------------------------------------------------
=head1 NAME
Eval::Context - Evalute perl code in context wraper
=head1 SYNOPSIS
use Eval::Context ;
my $context = new Eval::Context(PRE_CODE => "use strict;\nuse warnings;\n") ;
# code will be evaluated with strict and warnings loaded in the context.
$context->eval(CODE => 'print "evaluated in an Eval::Context!" ;') ;
$context->eval(CODE_FROM_FILE => 'file.pl') ;
=head1 DESCRIPTION
This module define a subroutine that let you evaluate Perl code in a specific context. The code can be passed directly as
a string or as a file name to read from. It also provides some subroutines to let you define and optionally share
variables and subroutines between your code and the code you wish to evaluate. Finally there is some support for running
your code in a safe compartment.
=head1 Don't play with fire!
Don't start using this module, or any other module, thinking it will let you take code from anywhere and be
safe. Read perlsec, Safe, Opcode, Taint and other security related documents. Control your input.
=head1 SUBROUTINES/METHODS
Subroutines that are not part of the public interface are marked with [p].
=cut
#-------------------------------------------------------------------------------
Readonly my $NEW_ARGUMENTS =>
[qw(
NAME PACKAGE SAFE PERL_EVAL_CONTEXT
PRE_CODE POST_CODE REMOVE_PACKAGE_AFTER_EVAL
INSTALL_SUBS INSTALL_VARIABLES EVAL_SIDE_PERSISTENT_VARIABLES
INTERACTION FILE LINE DISPLAY_SOURCE_IN_CONTEXT
)] ;
sub new
{
=head2 new(@named_arguments)
Create an Eval::Context object. The object is used as a repository of "default" values for your code evaluations.
The context can be used many times. The values can be temporarily overridden during the C<eval> call.
my $context = new Eval::Context() ; # default context
my $context = new Eval::Context
(
NAME => 'libraries evaluation context',
PACKAGE => 'libraries',
SAFE => {...} ;
PRE_CODE => "use strict ;\n"
POST_CODE => sub{},
PERL_EVAL_CONTEXT => undef,
INSTALL_SUBS => {...},
INSTALL_VARIABLES => [...],
EVAL_SIDE_PERSISTENT_VARIABLES => {...},
INTERACTION => {...},
DISPLAY_SOURCE_IN_CONTEXT => 1, #useful when debuging
) ;
I<ARGUMENTS>
=over 2
=item * @named_arguments - setup data for the object
All the arguments optional. The argument passed to C<new> can also be passed to C<eval>. All arguments are named.
=over 4
=item * NAME - use when displaying information about the object.
Set automatically to 'Anonymous' if not set. The name will also be reported
by perl if an error occurs during your code evaluation.
=item * PACKAGE - the package the code passed to C<eval> will evaluated be in.
If not set, a unique package name is generated and used for every C<eval> call.
=item * REMOVE_PACKAGE_AFTER_EVAL - When set the content of the package after evaluation will be erase
The default behavior is to remove all data from after the call to C<eval>.
=item * PRE_CODE - code prepended to the code passed to I<eval>
=item * POST_CODE - code appended to the code passed to I<eval>
=item * PERL_EVAL_CONTEXT - the context to eval code in (void, scalar, list).
This option Works as L<perlfunc/wantarray>. It will override the context in which C<eval> is called.
=item * INSTALL_SUBS - subs that will be available in the eval.
A hash where the keys are a function names and the values a code references.
=item * SAFE
This argument must be a hash reference. if the hash is empty, a default safe compartment will be used.
Read L<Safe> documentation for more information.
SAFE => {} # default safe environment
You can have a finer control over the safe compartment B<Eval::Context> that will be used.
my $compartment = new Safe('ABC') ;
my $context = new Eval::Context
(
SAFE => # controlling the safe environment
{
PACKAGE => 'ABC',
PRE_CODE => "use my module ;\n" # code we consider safe
USE_STRICT => 0, # set to 1 by default
COMPARTMENT => $compartment , # use default if not passed
} ,
}
$context->eval(CODE => .....) ;
=over 4
=item * COMPARTMENT - a Safe object, you create, that will be used by B<Eval::Context>
=item * USE_STRICT - Controls if L<strict> is used in the Safe compartment
The default is to use strict. Note that L<perldoc/Safe> default is to NOT use strict (undocumented).
=item * PRE_CODE - safe code you want to evaluate in the same context as the unsafe code
This let you, for example, use certain modules which provide subroutines to be used
in the evaluated code. The default compartment is quite restrictive and you can't even use
L<strict> in it without tuning the safe compartment.
=back
A few remarks:
- See L<http://rt.cpan.org/Ticket/Display.html?id=31090> on RT
- Pass the same package name to your safe compartment and to B<Eval::Context>.
- If you really want to be on the safe side, control your input. When you use a module, are you
sure the module hasn't been fiddle with?
- Leave strict on. Even for trivial code.
=item * INSTALL_VARIABLES - "Give me sugar baby" Ash.
B<Eval::Context> has mechanisms you can use to set and share variables with the
code you will evaluate. There are two sides in an B<Eval::Context>. The I<caller-side>,
the side where the calls to C<eval> are made and the I<eval-side>, the side where the code to
be evaluated is run.
=over 4
=item * How should you get values back from the eval-side
Although you can use the mechanisms below to get values from the I<eval-side>, the cleanest
way is to get the results directly from the C<eval> call.
my $context = new Eval::Context() ;
my ($scalr_new_value, $a_string) =
$context->eval
(
INSTALL_VARIABLES =>[[ '$scalar' => 42]] ,
CODE => "\$scalar++ ;\n (\$scalar, 'a string') ;",
) ;
=item * initializing variables on the I<eval side>
You can pass B<INSTALL_VARIABLES> to C<new> or C<eval>. You can initialize different variables
for each run of C<eval>.
my $context = new Eval::Context
(
INSTALL_VARIABLES =>
[
# variables on eval-side #initialization source
[ '$data' => 42],
[ '$scalar' => $scalar_caller_side ],
[ '%hash' => \%hash_caller_side ]
[ '$hash' => \%hash_caller_side ],
[ '$object' => $object ],
] ,
) ;
The variables will be B<my> variables on the eval-side.
You can declare variables of any of the base types supported by perl. The initialization
data , on the caller-side, is serialized and deserialized to make the values available
on the eval-side. Modifying the variables on the eval-side does not modify the variables
on the caller-side. The initialization data can be scalars or references and even B<my>
variables.
=item * Persistent variables
When evaluating code many times in the same context, you may wish to have variables persist
between evaluations. B<Eval::Context> allows you to declare, define and control such
I<state> variables.
This mechanism lets you control which variables are persistent. Access to the persistent
variables is controlled per C<eval> run. Persistent variables are B<my> variables on
the I<eval-side>. Modifying the variables on the eval-side does not modify the variables
on the I<caller-side>.
Define persistent variables:
# note: creating persistent variables in 'new' makes little sense as
# it will force those values in the persistent variables for every run.
# This may or may not be what you want.
my $context = new Eval::Context() ;
$context->eval
(
INSTALL_VARIABLES =>
[
[ '$scalar' => 42 => $Eval::Context::PERSISTENT ] ,
# make %hash and $hash available on the eval-side. both are
# initialized from the same caller-side hash
[ '%hash' => \%hash_caller_side => $Eval::Context::PERSISTENT ] ,
[ '$hash' => \%hash_caller_side => $Eval::Context::PERSISTENT ] ,
],
CODE => '$scalar++',
) ;
Later, use the persistent value:
$context->eval
(
INSTALL_VARIABLES =>
[
[ '$scalar' => $Eval::Context::USE => $Eval::Context::PERSISTENT ] ,
# here you decided %hash and $hash shouldn't be available on the eval-side
],
CODE => '$scalar',
) ;
B<$Eval::Context::USE> means I<"make the persistent variable and it's value available on the eval-side">.
Any other value will reinitialize the persistent variable. See also B<REMOVE_PERSISTENT> in C<eval>.
=item * Manually synchronizing caller-side data with persistent eval-side data
Although the first intent of persistent variables is to be used as state variables on
the eval-side, you can get persistent variables values on the caller-side. To change the
value of an I<eval-side> persistent variable, simply reinitialize it with B<INSTALL_VARIABLES>
next time you call C<eval>.
my $context = new Eval::Context
(
INSTALL_VARIABLES =>
[
['%hash' => \%hash_caller_side => $Eval::Context::PERSISTENT]
] ,
) ;
$context->Eval(CODE => '$hash{A}++ ;') ;
# throws exception if you request a non existing variable
my %hash_after_eval = $context->GetPersistantVariables('%hash') ;
=item * Getting the list of all the PERSISTENT variables
my @persistent_variable_names = $context->GetPersistantVariablesNames() ;
=item * Creating persistent variables on the eval-side
The mechanism above gave you fine control over persistent variables on the I<eval-side>.
The negative side is that B<only> the variables you made persistent exist on the I<eval-side>.
B<Eval::Context> has another mechanism that allows the I<eval-side> to store variables
between evaluations without the I<caller-side> declaration of the variables.
To allow the I<eval-side> to store any variable, add this to you C<new> call.
my $context = new Eval::Context
(
PACKAGE => 'my_package',
EVAL_SIDE_PERSISTENT_VARIABLES =>
{
SAVE => { NAME => 'SavePersistent', VALIDATOR => sub{} },
GET => { NAME => 'GetPersistent', VALIDATOR => sub{} },
},
) ;
The I<eval-side> can now store variables between calls to C<eval>
SavePersistent('name', $value) ;
later in another call to C<eval>:
my $variable = GetPersistent('name') ;
By fine tuning B<EVAL_SIDE_PERSISTENT_VARIABLES> you can control what variables are stored
by the I<eval-side>. This should seldom be used and only to help those storing data from
the I<eval-side>.
You may have notices in the code above that a package name was passed as argument to C<new>. This
is very important as the package names that are automatically generated differ for each
C<eval> call. If you want to run all you I<eval-side> code in different packages (B<Eval::Context>
default behavior), you must tell B<Eval::Context> where to store the I<eval-side> values. This is
done by setting B<CATEGORY>
The validator sub can verify if the value to be stored are valid, E.G.: variable name, variable
value is within range, ...
Here is an example of code run in different packages but can share variables. Only variables
which names start with I<A> are valid.
new Eval::Context
(
EVAL_SIDE_PERSISTENT_VARIABLES =>
{
CATEGORY => 'TEST',
SAVE =>
{
NAME => 'SavePersistent',
VALIDATOR => sub
{
my ($self, $name, $value, $package) = @_ ;
$self->{INTERACTION}{DIE}->
(
$self,
"SavePersistent: name '$name' doesn't start with A!"
) unless $name =~ /^A/ ;
},
},
GET => {NAME => 'GetPersistent',VALIDATOR => sub {}},
},
) ;
$context->eval(CODE => 'SavePersistent('A_variable', 123) ;') ;
later:
$context->eval(CODE => 'GetPersistent('A_variable') ;') ;
=item * Shared variables
You can also share references between the I<caller-side> and the I<eval-side>.
my $context =
new Eval::Context
(
INSTALL_VARIABLES =>
[
# reference to reference only
[ '$scalar' => \$scalar => $Eval::Context::SHARED ],
[ '$hash' => \%hash_caller_side => $Eval::Context::SHARED ],
[ '$object' => $object => $Eval::Context::SHARED ],
] ,
) ;
Modification of the variables on the I<eval-side> will modify the variable on the I<caller-side>.
There are but a few reasons to share references. Note that you can share references to B<my> variables.
=back
=item * INTERACTION
Lets you define subs used to interact with the user.
INTERACTION =>
{
INFO => \&sub,
WARN => \&sub,
DIE => \&sub,
EVAL_DIE => \&sub,
}
=over 6
=item INFO - defaults to CORE::print
This sub will be used when displaying information.
=item WARN - defaults to Carp::carp
This sub will be used when a warning is displayed.
=item DIE - defaults to Carp::confess
Used when an error occurs.
=item EVAL_DIE - defaults to Carp::confess, with a dump of the code to be evaluated
Used when an error occurs during code evaluation.
=back
=item * FILE - the file where the object has been created.
This is practical if you want to wrap the object.
B<FILE> and B<LINE> will be set automatically if not set.
=item * LINE - the line where the object has been created. Set automatically if not set.
=item * DISPLAY_SOURCE_IN_CONTEXT - if set, the code to evaluated will be displayed before evaluation
=back
=back
I<Return>
=over 2
=item * an B<Eval::Context> object.
=back
=cut
my ($invocant, @setup_data) = @_ ;
my $class = ref($invocant) || $invocant ;
confess 'Invalid constructor call!' unless defined $class ;
my $object = {} ;
my ($package, $file_name, $line) = caller() ;
bless $object, $class ;
$object->Setup($package, $file_name, $line, @setup_data) ;
return($object) ;
}
#-------------------------------------------------------------------------------
sub Setup
{
=head2 [p] Setup
Helper sub called by new.
=cut
my ($self, $package, $file_name, $line, @setup_data) = @_ ;
my $inital_option_checking_context = { NAME => 'Anonymous eval context', FILE => $file_name, LINE => $line,} ;
SetInteractionDefault($inital_option_checking_context) ;
CheckOptionNames
(
$inital_option_checking_context,
$NEW_ARGUMENTS,
@setup_data
) ;
%{$self} =
(
NAME => 'Anonymous',
FILE => $file_name,
LINE => $line,
REMOVE_PACKAGE_AFTER_EVAL => 1,
@setup_data,
) ;
if((! defined $self->{NAME}) || $self->{NAME} eq $EMPTY_STRING)
{
$self->{NAME} = 'Anonymous eval context' ;
}
SetInteractionDefault($self) ;
return(1) ;
}
#-------------------------------------------------------------------------------
sub CheckOptionNames
{
=head2 [p] CheckOptionNames
Verifies the named options passed as arguments with a list of valid options. Calls B<{INTERACTION}{DIE}> in case
of error.
=cut
my ($self, $valid_options, @options) = @_ ;
if (@options % 2)
{
$self->{INTERACTION}{DIE}->($self, "Invalid number of argument at '$self->{FILE}:$self->{LINE}'!") ;
}
if('HASH' eq ref $valid_options)
{
# OK
}
elsif('ARRAY' eq ref $valid_options)
{
$valid_options = {map{$_ => 1} @{$valid_options}} ;
}
else
{
$self->{INTERACTION}{DIE}->($self, q{Invalid 'valid_options' definition! Should be an array or hash reference.}) ;
}
my %options = @options ;
for my $option_name (keys %options)
{
unless(exists $valid_options->{$option_name})
{
$self->{INTERACTION}{DIE}->($self, "$self->{NAME}: Invalid Option '$option_name' at '$self->{FILE}:$self->{LINE}'!") ;
}
}
if
(
(defined $options{FILE} && ! defined $options{LINE})
|| (!defined $options{FILE} && defined $options{LINE})
)
{
$self->{INTERACTION}{DIE}->($self, "$self->{NAME}: Incomplete option FILE::LINE!") ;
}
return(1) ;
}
#-------------------------------------------------------------------------------
sub SetInteractionDefault
{
=head2 [p] SetInteractionDefault
Sets {INTERACTION} fields that are not set by the user.
=cut
my ($interaction_container) = @_ ;
$interaction_container->{INTERACTION}{INFO} ||= sub {my (@information) = @_ ; print @information} ; ## no critic (InputOutput::RequireCheckedSyscalls)
$interaction_container->{INTERACTION}{WARN} ||= \&Carp::carp ;
$interaction_container->{INTERACTION}{DIE} ||= sub { my($self, @error) = @_ ; Carp::confess(@error)} ;
$interaction_container->{INTERACTION}{EVAL_DIE} ||=
sub {
my($self, $error) = @_ ;
Carp::confess
(
"*** Eval::Context code ***\n"
. $self->{LATEST_CODE}
. "\n*** Error below ***\n"
. $error
) ;
} ;
return ;
}
#-------------------------------------------------------------------------------
sub CanonizeName
{
=head2 [p] CanonizeName
Transform a string into a a string with can be used as a package name or file name usable
within perl code.
=cut
my ($name) = @_ ;
croak 'CanonizeName called with undefined argument!' unless defined $name ;
$name =~ s/[^a-zA-Z0-9_:\.]/_/xsmg ;
return($name) ;
}
#-------------------------------------------------------------------------------
Readonly my $EVAL_ARGUMENTS => [@{$NEW_ARGUMENTS}, qw(CODE CODE_FROM_FILE REMOVE_PERSISTENT)] ;
sub eval ## no critic (Subroutines::ProhibitBuiltinHomonyms ErrorHandling::RequireCheckingReturnValueOfEval)
{
=head2 eval(@named_arguments)
Evaluates Perl code, passed as a string or read from a file, in the context.
my $context = new Eval::Context(PRE_CODE => "use strict;\nuse warnings;\n") ;
$context->eval(CODE => 'print "evaluated in an Eval::Context!";') ;
$context->eval(CODE_FROM_FILE => 'file.pl') ;
I<Call context>
Evaluation context of the code (void, scalar, list) is the same as the context this subroutine was called in
or in the context defined by B<PERL_EVAL_CONTEXT> if that option is present.
I<Arguments>
B<NOTE: You can override any argument passed to >C<new>B<. The override is temporary during
the duration of this call.>
=over 2
=item * @named_arguments - Any of C<new> options plus the following.
=over 4
=item * CODE - a string containing perl code (valid code or an exception is raised)
=item * CODE_FROM_FILE - a file containing perl code
=item * REMOVE_PERSISTENT
A list of regex used to match the persistent variable names to be removed, persistent variable removal
is done before any variable installation is done
=item * FILE and LINE - will be used in the evaluated code 'file_name' set to the caller's file and line by default
=back
NOTE: B<CODE> or B<CODE_FROM_FILE> is B<mandatory>.
=back
I<Return>
=over 2
=item * What the code to be evaluated returns
=back
=cut
my ($self, @options) = @_ ;
my $options = $self->VerifyAndCompleteOptions($EVAL_ARGUMENTS, @options) ;
$options->{PERL_EVAL_CONTEXT} = wantarray unless exists $options->{PERL_EVAL_CONTEXT} ;
my ($package, $variables_setup, $variables_teardown) = $self->EvalSetup($options) ;
my ($code_start, $code_end, $return) = $self->GetCallContextWrapper($variables_setup, $options) ;
my ($package_setup, $compartment, $compartment_use_strict, $pre_code_commented_out)
= $self->SetupSafeCompartment($package, $options) ;
$self->VerifyCodeInput($options) ;
$self->{LATEST_CODE} = "#line 0 '$options->{EVAL_FILE_NAME}'\n" ;
for
(
$package_setup,
$pre_code_commented_out,
'# PRE_CODE',
$options->{PRE_CODE},
$variables_setup,
$code_start,
"#line 0 '$options->{EVAL_FILE_NAME}'",
'# CODE',
$options->{CODE},
'# POST_CODE',
$options->{POST_CODE},
$code_end,
$variables_teardown,
$return,
"#end of context '$options->{EVAL_FILE_NAME}'",
)
{
$self->{LATEST_CODE} .= "$_\n" if defined $_ ;
}
if($options->{DISPLAY_SOURCE_IN_CONTEXT})
{
$options->{INTERACTION}{INFO}
->("Eval::Context called at '$options->{FILE}:$options->{LINE}' to evaluate:\n" . $self->{LATEST_CODE}) ;
}
if(defined $options->{PERL_EVAL_CONTEXT})
{
if($options->{PERL_EVAL_CONTEXT})
{
my @results =
$compartment
? $compartment->reval($self->{LATEST_CODE}, $compartment_use_strict)
: eval $self->{LATEST_CODE} ; ## no critic (BuiltinFunctions::ProhibitStringyEval)
$options->{INTERACTION}{EVAL_DIE}->($self, $EVAL_ERROR) if($EVAL_ERROR) ;
$self->EvalCleanup($options) ;
return @results ;
}
else
{
my $result =
$compartment
? $compartment->reval($self->{LATEST_CODE}, $compartment_use_strict)
: eval $self->{LATEST_CODE} ; ## no critic (BuiltinFunctions::ProhibitStringyEval)
$options->{INTERACTION}{EVAL_DIE}->($self, $EVAL_ERROR) if($EVAL_ERROR) ;
$self->EvalCleanup($options) ;
return $result ;
}
}
else
{
defined $compartment
? $compartment->reval($self->{LATEST_CODE}, $compartment_use_strict)
: eval $self->{LATEST_CODE} ; ## no critic (BuiltinFunctions::ProhibitStringyEval)
$options->{INTERACTION}{EVAL_DIE}->($self, $EVAL_ERROR) if($EVAL_ERROR) ;
$self->EvalCleanup($options) ;
return ;
}
}
#-------------------------------------------------------------------------------
sub VerifyAndCompleteOptions
{
=head2 [p] VerifyAndCompleteOptions
Helper sub for C<eval>.
=cut
my ($self, $allowed_arguments, @options) = @_ ;
$self->CheckOptionNames($allowed_arguments, @options) ;
my %options = @options ;
unless(defined $options{FILE})
{
my ($package, $file_name, $line) = caller(1) ;
push @options, FILE => $file_name, LINE => $line
}
%options = (%{$self}, @options) ;
$options{NAME} = CanonizeName($options{NAME} . " called at $options{FILE}:$options{LINE}") ;
SetInteractionDefault(\%options) ;
return(\%options) ;
}
#-------------------------------------------------------------------------------
sub EvalCleanup
{
=head2 [p] EvalCleanup
Handles the package cleanup or persistent variables cleanup after a call to C<eval>.
=cut
my ($self, $options) = @_ ;
if($options->{REMOVE_PACKAGE_AFTER_EVAL})
{
delete_package($self->{CURRENT_RUNNING_PACKAGE})
}
else
{
if(defined $options->{EVAL_SIDE_PERSISTENT_VARIABLES})
{
$self->RemoveEvalSidePersistenceHandlers($options) ;
}
}
return(1) ;
}
#-------------------------------------------------------------------------------
my $eval_run = 0 ;
sub GetPackageName
{
=head2 [p] GetPackageName
Returns a canonized package name. the name is either passed as argument from the caller
or a temporary package name.
=cut
my ($options) = @_ ;
my $package = exists $options->{PACKAGE} && defined $options->{PACKAGE}
? CanonizeName($options->{PACKAGE})
: "Eval::Context::Run_$eval_run" ;
$package = $package eq $EMPTY_STRING ? "Eval::Context::Run_$eval_run" : $package ;
$eval_run++ ;
return($package) ;
}
#-------------------------------------------------------------------------------
sub EvalSetup
{
=head2 [p] EvalSetup
Handles the setup of the context before I<eval-side> code is evaluated. Sets
the variables and the shared subroutines.
=cut
my ($self, $options) = @_ ;
my $package = $self->{CURRENT_RUNNING_PACKAGE} = GetPackageName($options) ;
$self->RemovePersistent($options) ;
my ($variables_setup, $variables_teardown) = (undef, undef) ;
if(defined $options->{INSTALL_VARIABLES})
{
($variables_setup, $variables_teardown) = $self->GetInstalledVariablesCode($options) ;
}
for my $sub_name (keys %{$options->{INSTALL_SUBS}})
{
if('CODE' ne ref $options->{INSTALL_SUBS}{$sub_name} )
{
$options->{INTERACTION}{DIE}->($self, "$self->{NAME}: '$sub_name' from 'INSTALL_SUBS' isn't a code reference at '$options->{FILE}:$options->{LINE}'!") ;
}
reinstall_sub({ code => $options->{INSTALL_SUBS}{$sub_name}, into => $package, as => $sub_name }) ;
}
if(defined $options->{EVAL_SIDE_PERSISTENT_VARIABLES})
{
$self->SetEvalSidePersistenceHandlers($options) ;
}
return ($package, $variables_setup, $variables_teardown) ;
}
#-------------------------------------------------------------------------------
sub VerifyCodeInput
{
=head2 [p] VerifyCodeInput
Verify that B<CODE> or B<CODE_FROM_FILE> are properly set.
=cut
my ($self, $options) = @_ ;
$options->{EVAL_FILE_NAME} = $options->{NAME} || 'Anonymous' ;
$options->{PRE_CODE} = defined $options->{PRE_CODE} ? $options->{PRE_CODE} : $EMPTY_STRING ;
if(exists $options->{CODE_FROM_FILE} && exists $options->{CODE} )
{
$options->{INTERACTION}{DIE}->($self, "$self->{NAME}: Option 'CODE' and 'CODE_FROM_FILE' can't coexist at '$options->{FILE}:$options->{LINE}'!") ;
}
if(exists $options->{CODE_FROM_FILE} && defined $options->{CODE_FROM_FILE})
{
$options->{CODE} = read_file($options->{CODE_FROM_FILE}) ;
$options->{NAME} = CanonizeName($options->{CODE_FROM_FILE}) ;
$options->{EVAL_FILE_NAME} = $options->{CODE_FROM_FILE} ;
}
unless(exists $options->{CODE} && defined $options->{CODE})
{
$options->{INTERACTION}{DIE}->($self, "$self->{NAME}: Invalid Option 'CODE' at '$options->{FILE}:$options->{LINE}'!") ;
}
$options->{POST_CODE} = defined $options->{POST_CODE} ? $options->{POST_CODE} : $EMPTY_STRING ;
return(1) ;
}
#-------------------------------------------------------------------------------
sub RemovePersistent
{
=head2 [p] RemovePersistent
Handles the removal of persistent variables.
=cut
my ($self, $options) = @_ ;
if(exists $options->{REMOVE_PERSISTENT})
{
if('ARRAY' ne ref $options->{REMOVE_PERSISTENT})
{
$options->{INTERACTION}{DIE}->
(
$self,
"$self->{NAME}: 'REMOVE_PERSISTENT' must be an array reference containing regexes at '$options->{FILE}:$options->{LINE}'!"
) ;
}
for my $regex (@{ $options->{REMOVE_PERSISTENT} })
{
for my $name ( keys %{ $self->{PERSISTENT_VARIABLES} })
{
delete $self->{PERSISTENT_VARIABLES}{$name} if($name =~ $regex) ;
}
}
}
return(1) ;
}
#-------------------------------------------------------------------------------
sub GetCallContextWrapper
{
=head2 [p] GetCallContextWrapper
Generates perl code to wrap the code to be evaluated in the right calling context.
=cut
my ($self, $variables_setup, $options) = @_ ;
my ($code_start, $code_end, $return) = (undef, undef, undef) ; # defaults for void context
if(defined $variables_setup)
{
if(defined $options->{PERL_EVAL_CONTEXT})
{
if($options->{PERL_EVAL_CONTEXT})
{
# array context
($code_start, $code_end, $return) =
(
"my \@eval_context_result = do {\n",
"} ;\n",
"\@eval_context_result ;\n",
) ;
}
else
{
# scalar context
($code_start, $code_end, $return) =
(
"my \$eval_context_result = do {\n",
"} ;\n",
"\$eval_context_result ;\n",
) ;
}
}
else
{
# void context
($code_start, $code_end, $return) = ($EMPTY_STRING, $EMPTY_STRING, $EMPTY_STRING) ;
}
}
return($code_start, $code_end, $return) ;
}
#-------------------------------------------------------------------------------
sub SetupSafeCompartment
{
=head2 [p] SetupSafeCompartment
If running in safe mode, setup a safe compartment from the argument, otherwise defines the evaluation package.
=cut
my ($self, $package, $options) = @_ ;
my ($package_setup, $compartment, $compartment_use_strict, $pre_code_commented_out) = (undef, undef, 1, undef) ;
if(exists $options->{SAFE})
{
if('HASH' eq ref $options->{SAFE})
{
if(exists $options->{SAFE}{PRE_CODE})
{
# must be done before creating the safe compartment
my $pre_code = "\npackage " . $package . " ;\n" . $options->{SAFE}{PRE_CODE} ;
eval $pre_code ; ## no critic (BuiltinFunctions::ProhibitStringyEval)
if($EVAL_ERROR)
{
$self->{LATEST_CODE} = $pre_code ;
$options->{INTERACTION}{EVAL_DIE}->($self, $EVAL_ERROR) ;
}
$pre_code_commented_out =
"# Note: evaluated PRE_CODE before running SAFE code\n"
. "=comment\n\n"
. $pre_code
. "\n\n=cut\n" ;
}
if(exists $options->{SAFE}{COMPARTMENT})
{
$compartment = $options->{SAFE}{COMPARTMENT} ;
}
else
{
$compartment = new Safe($package) ;
}
$compartment_use_strict = $options->{SAFE}{USE_STRICT} if exists $options->{SAFE}{USE_STRICT} ;
}
else
{
$options->{INTERACTION}{DIE}->($self, "$self->{NAME}: Invalid Option 'SAFE' definition at '$options->{FILE}:$options->{LINE}'!") ;
}
}
else
{
$package_setup = "package $package ;"
}
return($package_setup, $compartment, $compartment_use_strict, $pre_code_commented_out) ;
}
#-------------------------------------------------------------------------------
Readonly my $SET_FROM_CALLER => 2 ;
Readonly my $SET_FROM_CALLER_WITH_TYPE => 3 ;
Readonly my $NAME_INDEX => 0 ;
Readonly my $VALUE_INDEX => 1 ;
Readonly my $TYPE_INDEX => 2 ;
sub GetInstalledVariablesCode
{
=head2 [p] GetInstalledVariablesCode
Generates variables on the eval-side from the INSTALL_VARIABLES definitions.
Dispatches the generation to specialize subroutines.
=cut
my ($self, $options) = @_ ;
my ($setup_code, $teardown_code) = ($EMPTY_STRING, $EMPTY_STRING) ;
for my $variable_definition (@{ $options->{INSTALL_VARIABLES} })
{
my $definition_type = scalar(@{$variable_definition}) ;
my $variable_name = $variable_definition->[$NAME_INDEX] ;
my $variable_value = $variable_definition->[$VALUE_INDEX] ;
my $variable_type = ref $variable_value ;
if($SET_FROM_CALLER == $definition_type)
{
my ($setup, $teardown) = $self->GetVariablesSetFromCaller($options, $variable_name, $variable_value, $variable_type) ;
$setup_code .= $setup ;
$teardown_code .= $teardown ;
}
elsif($SET_FROM_CALLER_WITH_TYPE == $definition_type)
{
if($variable_definition->[$TYPE_INDEX] == $PERSISTENT)
{
my ($setup, $teardown) = $self->GetPersistentVariablesSetFromCaller
(
$options,
$variable_name,
$variable_value,
$variable_type,
) ;
$setup_code .= $setup ;
$teardown_code .= $teardown ;
}
elsif($variable_definition->[$TYPE_INDEX] == $SHARED)
{
my ($setup, $teardown) = $self->GetSharedVariablesSetFromCaller
(
$options,
$variable_name,
$variable_value,
$variable_type,
) ;
$setup_code .= $setup ;
$teardown_code .= $teardown ;
}
else
{
$self->{INTERACTION}{DIE}->($self, "Variable '$variable_name' type must be SHARED or PERSISTENT at '$options->{FILE}:$options->{LINE}'!") ;
}
}
else
{
$self->{INTERACTION}{DIE}->($self, "Invalid variable definition at '$options->{FILE}:$options->{LINE}'!") ;
}
}
return($setup_code, $teardown_code) ;
}
#-------------------------------------------------------------------------------
my $temporary_name_index = 0 ;
sub GetPersistentVariablesSetFromCaller
{
=head2 [p] GetPersistentVariablesSetFromCaller
Generates code to make persistent variables, defined on the I<caller-side> available on the I<eval-side>.
=cut
my ($self, $options, $variable_name, $variable_value, $variable_type) = @_ ;
my $persistance_handler_name = 'EvalContextSavePersistentVariable' ;
my ($setup_code, $teardown_code) = ($EMPTY_STRING, $EMPTY_STRING) ;
if(exists $self->{SHARED_VARIABLES}{$variable_name})
{
$self->{INTERACTION}{DIE}->($self, "'$variable_name' can't be PERSISTENT, already SHARED, at '$options->{FILE}:$options->{LINE}'!") ;
}
if(! exists $self->{PERSISTENT_VARIABLES}{$variable_name})
{
($setup_code, undef) = $self->GetVariablesSetFromCaller($options, $variable_name, $variable_value, $variable_type) ;
$setup_code = "# PERSISTENT, did not exist '$variable_name'\n" . $setup_code ;
}
else
{
if(ref $variable_value eq 'USE_PERSISTENT')
{
$setup_code = "# PERSISTENT, existed '$variable_name'\n"
. "my $self->{PERSISTENT_VARIABLES}{$variable_name}\n" ;
}
else
{
($setup_code, undef) = $self->GetVariablesSetFromCaller($options, $variable_name, $variable_value, $variable_type) ;
$setup_code = "# PERSISTENT, existed '$variable_name', overridden \n" . $setup_code ;
}
}
# save the persistent variables after the user code is run
$teardown_code = "$persistance_handler_name('$variable_name', \\$variable_name) ;\n" ;
# install the subroutines needed to save the persistent variables
reinstall_sub
({
code => sub
{
my ($variable_name, $variable_ref) = @_ ;
my $dump_name = $variable_name ;
substr($dump_name, 0, 1, $EMPTY_STRING) ;
if('SCALAR' eq ref $variable_ref)
{
if(defined ${$variable_ref})
{
$self->{PERSISTENT_VARIABLES}{$variable_name} = "$variable_name = '${$variable_ref}' ;" ;
}
else
{
$self->{PERSISTENT_VARIABLES}{$variable_name} = "$variable_name = undef ;" ;
}
}
elsif('REF' eq ref $variable_ref)
{
$self->{PERSISTENT_VARIABLES}{$variable_name} = Data::Dumper->Dump([${$variable_ref}], [$dump_name]) ;
}
else
{
# convert and serialize at once
my ($sigil, $name) = $variable_name =~ /(.)(.*)/sxm ;
$self->{PERSISTENT_VARIABLES}{$variable_name} = Data::Dumper->Dump([$variable_ref], [$name]) ;
$self->{PERSISTENT_VARIABLES}{$variable_name} =~ s/\$$name\ =\ ./$variable_name = (/xsm ;
$self->{PERSISTENT_VARIABLES}{$variable_name} =~ s/.;\Z/) ;/xsm ;
}
},
into => $self->{CURRENT_RUNNING_PACKAGE},
as => $persistance_handler_name,
}) ;
return($setup_code, $teardown_code) ;
}
#-------------------------------------------------------------------------------
our %shared_variables ; ## no critic (Variables::ProhibitPackageVars)
sub GetSharedVariablesSetFromCaller
{
=head2 [p] GetSharedVariablesSetFromCaller
Handles the mechanism used to share variables (references) between the I<caller-side>
and the I<eval-side>.
Shared variables must be defined and references. If the shared variable is B<undef>, the variable
that was previously shared, under the passed name, is used if it exists or an exception is raised.
Also check that variables are not B<PERSISTENT> and B<SHARED>.
=cut
my ($self, $options, $variable_name, $variable_value, $variable_type) = @_ ;
my ($setup_code, $teardown_code) = ($EMPTY_STRING, $EMPTY_STRING) ;
if(exists $self->{PERSISTENT_VARIABLES}{$variable_name})
{
$self->{INTERACTION}{DIE}->($self, "'$variable_name' can't be SHARED, already PERSISTENT, at '$options->{FILE}:$options->{LINE}'!") ;
}
if(defined $variable_value)
{
if($EMPTY_STRING eq ref $variable_value)
{
$self->{INTERACTION}{DIE}->($self, "Need a reference to share from for '$variable_name' at '$options->{FILE}:$options->{LINE}'!") ;
}
my $variable_share_name = "${variable_name}_$self->{FILE}_$self->{LINE}_$temporary_name_index" ;
$variable_share_name =~ s/[^a-zA-Z0-9_]+/_/xsmg ;
$temporary_name_index++ ;
$shared_variables{$variable_share_name} = $variable_value ;
if(exists $options->{SAFE})
{
$self->{SHARED_VARIABLES}{$variable_name} = $variable_share_name ;
}
else
{
# faster method
$self->{SHARED_VARIABLES}{$variable_name} = q{$} . __PACKAGE__ . "::shared_variables{$variable_share_name}" ;
}
}
if(exists $self->{SHARED_VARIABLES}{$variable_name})
{
if(exists $options->{SAFE})
{
$setup_code = "my $variable_name = EvalContextSharedVariable('$self->{SHARED_VARIABLES}{$variable_name}') ;\n" ;
reinstall_sub({
code => sub {my ($variable_name) = @_ ; return($shared_variables{$variable_name}) ;},
into => $self->{CURRENT_RUNNING_PACKAGE},
as => 'EvalContextSharedVariable',
}) ;
}
else
{
$setup_code = "my $variable_name = $self->{SHARED_VARIABLES}{$variable_name} ;\n" ; # not in Safe, we can access other packages
}
}
else
{
$self->{INTERACTION}{DIE}->($self, "Nothing previously shared to '$variable_name' at '$options->{FILE}:$options->{LINE}'!") ;
}
return($setup_code, $teardown_code) ;
}
#-------------------------------------------------------------------------------
my %valid_sigil = map {$_ => 1} qw($ @ %) ;
sub GetVariablesSetFromCaller
{
=head2 [p] GetVariablesSetFromCaller
Generates code that creates local variables on the I<eval-side>
=cut
my ($self, $options, $variable_name, $variable_value, $variable_type) = @_ ;
my $DIE = $self->{INTERACTION}{DIE} ;
my $code_to_evaluate = $EMPTY_STRING ;
my ($sigil, $name) = $variable_name =~ /(.)(.*)/sxm ;
$DIE->($self, "Invalid variable type for '$variable_name' at '$options->{FILE}:$options->{LINE}'!") unless $valid_sigil{$sigil} ;
if(! defined $variable_value)
{
$code_to_evaluate .= "my $variable_name = undef ;\n" ;
}
else
{
if($EMPTY_STRING eq $variable_type)
{
$code_to_evaluate .= "my $variable_name = '$variable_value';\n" ;
}
else
{
# set from reference
my $conversion = $EMPTY_STRING ;
if($sigil eq q{$})
{
# reference to reference, no conversion needed
$conversion = Data::Dumper->Dump([$variable_value], [$variable_name] ) ;
}
else
{
$conversion = Data::Dumper->Dump([$variable_value], [$name]) ;
$conversion =~ s/\A\$$name\ =\ ./$variable_name = (/xsm ;
$conversion =~ s/.;\Z/) ;/xsm ;
}
$code_to_evaluate .= "my $conversion" ;
}
}
return($code_to_evaluate, $EMPTY_STRING) ;
}
#-------------------------------------------------------------------------------
sub GetPersistentVariableNames
{
=head2 GetPersistentVariableNames()
I<Arguments> - none
I<Returns> - the list of existing persistent variables names
my @persistent_variable_names = $context->GetPersistantVariablesNames() ;
=cut
my ($self) = @_ ;
return(keys %{ $self->{PERSISTENT_VARIABLES} }) ;
}
#-------------------------------------------------------------------------------
sub GetPersistantVariables
{
=head2 GetPersistantVariables(@variable_names)
I<Arguments>
=over 2
=item * @variable_names - list of variable names to retrieve
=back
I<Returns> - list of values corresponding to the input names
This subroutine will return whatever the I<caller-site> set or the I<eval-side> modified. Thus if
you created a I<%hash> persistent variable, a hash (not a hash reference) will be returned.
If you request multiple values, list flattening will be in effect. Be careful.
my $context = new Eval::Context
(
INSTALL_VARIABLES =>
[
['%hash' => \%hash_caller_side => $Eval::Context::PERSISTENT]
] ,
) ;
$context->Eval(CODE => '$hash{A}++ ;') ;
# may throw exception
my %hash_after_eval = $context->GetPersistantVariables('%hash') ;
=cut
my ($self, @variable_names) = @_ ;
my ($package, $file_name, $line) = caller() ;
my @values ;
for my $variable_name (@variable_names)
{
if(exists $self->{PERSISTENT_VARIABLES}{$variable_name})
{
my @variable_values = eval 'my ' . $self->{PERSISTENT_VARIABLES}{$variable_name} ; ## no critic (BuiltinFunctions::ProhibitStringyEval)
push @values, @variable_values ;
}
else
{
$self->{INTERACTION}{DIE}->
(
$self,
"PERSISTENT variable '$variable_name' doesn't exist, can't be fetched at '$file_name:$line'!"
) ;
}
}
if(defined wantarray)
{
if(wantarray)
{
return(@values) ;
}
else
{
return $values[0] ;
}
}
else
{
return #PBP
(
$self->{INTERACTION}{DIE}->
(
$self,
"GetPersistantVariables called in void context at '$file_name:$line'!"
)
)
}
}
#-------------------------------------------------------------------------------
sub SetEvalSidePersistenceHandlers
{
=head2 [p] SetEvalSidePersistenceHandlers
Set the code needed to handle I<eval-side> persistent variables.
=cut
my ($self, $options) = @_ ;
if('HASH' eq ref $options->{EVAL_SIDE_PERSISTENT_VARIABLES})
{
my $category = defined $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{CATEGORY}
? $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{CATEGORY}
: $self->{CURRENT_RUNNING_PACKAGE} ;
my %handler_sub_validators ;
my %handler_subs =
(
SAVE => sub
{
my (@name_values) = @_ ;
if(scalar(@_) % 2)
{
my ($package, $file_name, $line) = caller() ;
$self->{INTERACTION}{DIE}->
(
$self,
"$self->{NAME}: eval-side persistence handler got unexpected number of arguments "
. "at '$file_name:$line'!"
) ;
}
while(my ($variable_name, $value) = splice(@name_values, 0, 2))
{
$handler_sub_validators{SAVE}->($self, $variable_name, $value) ;
$self->{PERSISTENT_VARIABLES_FOR_EVAL_SIDE}{$category}{$variable_name} = $value ;
}
},
GET => sub
{
my @values ;
for my $variable_name (@_)
{
$handler_sub_validators{GET}->($self, $variable_name) ;
push @values, $self->{PERSISTENT_VARIABLES_FOR_EVAL_SIDE}{$category}{$variable_name} ;
}
return wantarray ? @values : $values[0] ;
},
) ;
for my $handler_type ('SAVE', 'GET')
{
if(exists $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type})
{
if
(
exists $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{VALIDATOR}
&& 'CODE' eq ref $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{VALIDATOR}
&& $EMPTY_STRING eq ref $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{NAME}
&& $EMPTY_STRING ne $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{NAME}
)
{
$handler_sub_validators{$handler_type} = $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{VALIDATOR} ;
reinstall_sub({
code => $handler_subs{$handler_type},
into => $self->{CURRENT_RUNNING_PACKAGE},
as => $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{NAME}
}) ;
}
else
{
$options->{INTERACTION}{DIE}->
(
$self,
"$self->{NAME}: 'EVAL_SIDE_PERSISTENT_VARIABLES' invalid definition "
. "at '$options->{FILE}:$options->{LINE}'!"
) ;
}
}
else
{
$options->{INTERACTION}{DIE}->
(
$self,
"$self->{NAME}: 'EVAL_SIDE_PERSISTENT_VARIABLES' missing handler definition "
. "at '$options->{FILE}:$options->{LINE}'!"
) ;
}
}
if($options->{EVAL_SIDE_PERSISTENT_VARIABLES}{SAVE}{NAME} eq $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{GET}{NAME})
{
$options->{INTERACTION}{DIE}->
(
$self,
"$self->{NAME}: invalid definition, eval-side persistence handlers have the same name "
. "at '$options->{FILE}:$options->{LINE}'!"
) ;
}
}
else
{
$options->{INTERACTION}{DIE}->($self, "$self->{NAME}: 'EVAL_SIDE_PERSISTENT_VARIABLES' isn't a hash reference at '$options->{FILE}:$options->{LINE}'!") ;
}
return(1) ;
}
#-------------------------------------------------------------------------------
sub RemoveEvalSidePersistenceHandlers
{
=head2 [p] RemoveEvalSidePersistenceHandlers
Removes I<eval-side> persistent variable handlers. Used after calling C<eval> so the
next C<eval> can not access I<eval-side> persistent variables without being allowed to do so.
=cut
my ($self, $options) = @_ ;
for my $handler_type ('SAVE', 'GET')
{
reinstall_sub({
code => sub
{
$options->{INTERACTION}{DIE}->
(
$self,
"$self->{NAME}: No Persistence allowed on eval-side in package '$self->{CURRENT_RUNNING_PACKAGE}'!\n"
) ;
},
into => $self->{CURRENT_RUNNING_PACKAGE},
as => $options->{EVAL_SIDE_PERSISTENT_VARIABLES}{$handler_type}{NAME}
}) ;
}
return(1) ;
}
#-------------------------------------------------------------------------------
1 ;
=head1 BUGS AND LIMITATIONS
I have reported a very strange error when B<Safe> and B<Carp> are used together.
L<http://rt.cpan.org/Ticket/Display.html?id=31090>. The error can be reproduced
without using B<Eval::Context>.
=head1 AUTHOR
Khemir Nadim ibn Hamouda
CPAN ID: NKH
mailto:nadim@khemir.net
=head1 LICENSE AND COPYRIGHT
This program is free software; you can redistribute
it and/or modify it under the same terms as Perl itself.
=head1 SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Eval::Context
You can also look for information at:
=over 4
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/Eval-Context>
=item * RT: CPAN's request tracker
Please report any bugs or feature requests to L <bug-eval-context@rt.cpan.org>.
We will be notified, and then you'll automatically be notified of progress on
your bug as we make changes.
=item * Search CPAN
L<http://search.cpan.org/dist/Eval-Context>
=back
=cut
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