/ 
Devel-PatchPerl-2.10-TRIAL
River stage two • 7 direct dependents • 18 total dependents
/ ExtUtils::ParseXS::Utilities

NAME

ExtUtils::ParseXS::Utilities - Subroutines used with ExtUtils::ParseXS

SYNOPSIS

use ExtUtils::ParseXS::Utilities qw(
  standard_typemap_locations
  trim_whitespace
  C_string
  valid_proto_string
  process_typemaps
  map_type
  standard_XS_defs
  analyze_preprocessor_statement
  set_cond
  Warn
  blurt
  death
  check_conditional_preprocessor_statements
  escape_file_for_line_directive
  report_typemap_failure
);

SUBROUTINES

The following functions are not considered to be part of the public interface. They are documented here for the benefit of future maintainers of this module.

standard_typemap_locations()

  • Purpose

    Provide a list of filepaths where typemap files may be found. The filepaths -- relative paths to files (not just directory paths) -- appear in this list in lowest-to-highest priority.

    The highest priority is to look in the current directory.

    'typemap'

    The second and third highest priorities are to look in the parent of the current directory and a directory called lib/ExtUtils underneath the parent directory.

    '../typemap',
'../lib/ExtUtils/typemap',

    The fourth through ninth highest priorities are to look in the corresponding grandparent, great-grandparent and great-great-grandparent directories.

    '../../typemap',
'../../lib/ExtUtils/typemap',
'../../../typemap',
'../../../lib/ExtUtils/typemap',
'../../../../typemap',
'../../../../lib/ExtUtils/typemap',

    The tenth and subsequent priorities are to look in directories named ExtUtils which are subdirectories of directories found in @INC -- provided a file named typemap actually exists in such a directory. Example:

    '/usr/local/lib/perl5/5.10.1/ExtUtils/typemap',

    However, these filepaths appear in the list returned by standard_typemap_locations() in reverse order, i.e., lowest-to-highest.

    '/usr/local/lib/perl5/5.10.1/ExtUtils/typemap',
'../../../../lib/ExtUtils/typemap',
'../../../../typemap',
'../../../lib/ExtUtils/typemap',
'../../../typemap',
'../../lib/ExtUtils/typemap',
'../../typemap',
'../lib/ExtUtils/typemap',
'../typemap',
'typemap'

  • Arguments

    my @stl = standard_typemap_locations( \@INC );

    Reference to @INC.

  • Return Value

    Array holding list of directories to be searched for typemap files.

trim_whitespace()

  • Purpose

    Perform an in-place trimming of leading and trailing whitespace from the first argument provided to the function.

  • Argument

    trim_whitespace($arg);

  • Return Value

    None. Remember: this is an in-place modification of the argument.

C_string()

  • Purpose

    Escape backslashes (\) in prototype strings.

  • Arguments

    $ProtoThisXSUB = C_string($_);

    String needing escaping.

  • Return Value

    Properly escaped string.

valid_proto_string()

  • Purpose

    Validate prototype string.

  • Arguments

    String needing checking.

  • Return Value

    Upon success, returns the same string passed as argument.

    Upon failure, returns 0.

process_typemaps()

  • Purpose

    Process all typemap files.

  • Arguments

    my $typemaps_object = process_typemaps( $args{typemap}, $pwd );

    List of two elements: typemap element from %args; current working directory.

  • Return Value

    Upon success, returns an ExtUtils::Typemaps object.

map_type($self, $type, $varname)

Returns a mapped version of the C type $type. In particular, it converts Foo::bar to Foo__bar, converts the special array(type,n) into type *, and inserts $varname (if present) into any function pointer type. So ...(*)... becomes ...(* foo)....

standard_XS_defs()

  • Purpose

    Writes to the .c output file certain preprocessor directives and function headers needed in all such files.

  • Arguments

    None.

  • Return Value

    Returns true.

analyze_preprocessor_statement()

  • Purpose

    Process a CPP conditional line (#if etc), to keep track of conditional nesting. In particular, it updates @{$self->{XS_parse_stack}} which contains the current list of nested conditions, and $self->{XS_parse_stack_top_if_idx} which indicates the most recent if in that stack. So an #if pushes, an #endif pops, an #else modifies etc. Each element is a hash of the form:

    {
  type      => 'if',
  varname   => 'XSubPPtmpAAAA', # maintained by caller

                # XS functions defined within this branch of the
                # conditional (maintained by caller)
  functions =>  {
                  'Foo::Bar::baz' => 1,
                  ...
                }
                # XS functions seen within any previous branch
  other_functions => {... }

    It also updates $self->{bootcode_early} and $self->{bootcode_late} with extra CPP directives.

  • Arguments

    $self->analyze_preprocessor_statement($statement);

set_cond()

  • Purpose

    Return a string containing a snippet of C code which tests for the 'wrong number of arguments passed' condition, depending on whether there are default arguments or ellipsis.

  • Arguments

    ellipsis true if the xsub's signature has a trailing , ....

    $min_args the smallest number of args which may be passed.

    $num_args the number of parameters in the signature.

  • Return Value

    The text of a short C code snippet.

current_line_number()

  • Purpose

    Figures out the current line number in the XS file.

  • Arguments

    $self

  • Return Value

    The current line number.

Error handling methods

There are four main methods for reporting warnings and errors.

$self->Warn(@messages)

This is equivalent to:

warn "@messages in foo.xs, line 123\n";

The file and line number are based on the file currently being parsed. It is intended for use where you wish to warn, but can continue parsing and still generate a correct C output file.

$self->blurt(@messages)

This is equivalent to Warn, except that it also increments the internal error count (which can be retrieved with report_error_count()). It is used to report an error, but where parsing can continue (so typically for a semantic error rather than a syntax error). It is expected that the caller will eventually signal failure in some fashion. For example, xsubpp has this as its last line:

exit($self->report_error_count() ? 1 : 0);
$self->death(@messages)

This normally equivalent to:

$self->Warn(@messages);
exit(1);

It is used for something like a syntax error, where parsing can't continue. However, this is inconvenient for testing purposes, as the error can't be trapped. So if $self is created with the die_on_error flag, or if $ExtUtils::ParseXS::DIE_ON_ERROR is true when process_file() is called, then instead it will die() with that message.

$self->WarnHint(@messages, $hints)

This is a more obscure twin to Warn, which does the same as Warn, but afterwards, outputs any lines contained in the $hints string, with each line wrapped in parentheses. For example:

$self->WarnHint(@messages,
  "Have you set the foo switch?\nSee the manual for further info");

check_conditional_preprocessor_statements()

  • Purpose

    Warn if the lines in @{ $self->{line} } don't have balanced #if, endif etc.

  • Arguments

    None

  • Return Value

    None

escape_file_for_line_directive()

  • Purpose

    Escapes a given code source name (typically a file name but can also be a command that was read from) so that double-quotes and backslashes are escaped.

  • Arguments

    A string.

  • Return Value

    A string with escapes for double-quotes and backslashes.

report_typemap_failure

  • Purpose

    Do error reporting for missing typemaps.

  • Arguments

    The ExtUtils::ParseXS object.

    An ExtUtils::Typemaps object.

    The string that represents the C type that was not found in the typemap.

    Optionally, the string death or blurt to choose whether the error is immediately fatal or not. Default: blurt

  • Return Value

    Returns nothing. Depending on the arguments, this may call death or blurt, the former of which is fatal.