File Coverage

open.xs

Criterion	Covered	Total	%
statement	52	59	88.1
branch	38	82	46.3
condition			n/a
subroutine			n/a
pod			n/a
total	90	141	63.8

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"

#define SAVE_AND_REPLACE_PP_IF_UNSET(real_function, op_to_replace, overload_function, OP_replace_mutex) do {\
    MUTEX_LOCK(&OP_replace_mutex);\
    if (!real_function) {\
        real_function = PL_ppaddr[op_to_replace];\
    }\
    if (PL_ppaddr[op_to_replace] != overload_function) {\
        PL_ppaddr[op_to_replace] = overload_function;\
    }\
    else {\
        /* Would be nice if we could warn here. */\
    }\
    MUTEX_UNLOCK(&OP_replace_mutex);\
} while (0)

#define overload_open_die_with_xs_sub 1
#define overload_open_max_function_pointers 2
OP* (*stuff_array[overload_open_max_function_pointers])(pTHX);
/* Declare function pointers for OP's */
OP* (*real_pp_open)(pTHX) = NULL;
OP* (*real_pp_sysopen)(pTHX) = NULL;

#define overload_open_max_args 99
#ifdef USE_ITHREADS
static perl_mutex OP_OPEN_replace_mutex;
static perl_mutex OP_SYSOPEN_replace_mutex;
#endif

OP * (*real_pp_open)(pTHX);
OP * (*real_pp_sysopen)(pTHX);
SV * cached_hook_open = NULL;
SV * cached_hook_sysopen = NULL;
CV * cached_code_hook_open = NULL;
CV * cached_code_hook_sysopen = NULL;
bool overload_is_sysopen(char *opname) {
    return strcmp(opname, "sysopen") == 0;
}
bool overload_is_open(char *opname) {
    return strcmp(opname, "open") == 0;
}
void set_cached_hooks_for_op (char *opname, SV *hook, CV *code_hook) {
    if (overload_is_open(opname)) {
        cached_hook_open      = hook;
        cached_code_hook_open = code_hook;
    }
    if (overload_is_sysopen(opname)) {
        cached_hook_sysopen      = hook;
        cached_code_hook_sysopen = code_hook;
    }
}
OP * overload_allopen(char *opname, char *global, OP* (*real_pp_func)(pTHX)) {
    SV *hook = get_sv(global, 0);
    /* If the hook evaluates as false, we should just call the original
     * function ( AKA overload::open->prehook_open() has not been called yet ) */
    if ( !hook || !SvTRUE( hook ) ) {
        set_cached_hooks_for_op(opname, NULL, NULL);
        return real_pp_func(aTHXR);
    }
    /* Check to make sure we have a coderef */
    if ( !SvROK( hook ) || SvTYPE( SvRV(hook) ) != SVt_PVCV ) {
        set_cached_hooks_for_op(opname, NULL, NULL);
        warn("override::open expected a code reference, but got something else");
        return real_pp_func(aTHXR);
    }
    /* Get the CV* that the reference refers to */
    CV* code_hook = (CV*) SvRV(hook);
    if ( CvISXSUB( code_hook ) ) {
        if ( overload_open_die_with_xs_sub )
            die("overload::open error. Cowardly refusing to hook an XS sub into %s", opname);
        return real_pp_func(aTHXR);
    }
    /* Found suitable hook. We can cache in now */
    set_cached_hooks_for_op(opname, hook, code_hook);

    /* CvDEPTH > 0 that means our hook is calling OP_OPEN. This is ok
     * just ensure we direct things to the original function */
    /* calling on the cached allows us to check the depth for both of the code functions */
    if (cached_code_hook_open) {
        if ( 0 < CvDEPTH( cached_code_hook_open ) ) {
            return real_pp_func(aTHXR);
        }
    }
    if (cached_code_hook_sysopen) {
        if ( 0 < CvDEPTH( cached_code_hook_sysopen ) ) {
            return real_pp_func(aTHXR);
        }
    }
    /* Once more for paranoia */
    if ( 0 < CvDEPTH( code_hook ) ) {
        return real_pp_func(aTHXR);
    }
    SV **sp = PL_stack_sp;
    ENTER;
        /* Save the temporaries stack */
        SAVETMPS;
            /* sp (stack pointer) is used by some macros we call below. mysp is *ours* */
            /* Save the stack pointer location */
            SV **mysp = PL_stack_sp;
            /* Save the number of items (number of arguments) */
            PUSHMARK(sp);
                ssize_t myitems = *PL_markstack_ptr;
                if (myitems < 0) {
                    DIE(aTHXR_ "panic: overload::open internal error. This should not happen.");
                }
                EXTEND(sp, myitems);
                ssize_t c;
                for ( c = 0; c < myitems; c++) {
                    /* We are going from last to first */
                    ssize_t i = myitems - 1 - c;
                    mPUSHs( newSVsv(*(mysp - i)) );
                }
            /*  PL_stack_sp = sp */
            PUTBACK; /* Closing bracket for XSUB arguments */
            I32 count = call_sv( (SV*)code_hook, G_VOID | G_DISCARD|G_EVAL |G_KEEPERR);
            /* G_VOID and G_DISCARD should cause us to not ask for any return
            * arguments from the call. */
            if (count) warn("call_sv was not supposed to get any arguments");
            /* The purpose of the macro "SPAGAIN" is to refresh the local copy of
            * the stack pointer. This is necessary because it is possible that
            * the memory allocated to the Perl stack has been reallocated during
            * the *call_pv* call */
            /*  sp = PL_stack_sp */
            SPAGAIN;

        /* FREETMPS cleans up all stuff on the temporaries stack added since SAVETMPS was called */
        FREETMPS;
    LEAVE;
    return real_pp_func(aTHXR);
}

PP(pp_overload_open) {
    return overload_allopen("open", "overload::open::GLOBAL_OPEN", real_pp_open);
}

PP(pp_overload_sysopen) {
    return overload_allopen("sysopen", "overload::open::GLOBAL_SYSOPEN",
        real_pp_sysopen);
}

MODULE = overload::open	PACKAGE = overload::open PREFIX = overload_open_

PROTOTYPES: ENABLE

void
_test_xs_function(...)
    CODE:
        printf("running test xs function\n");

void
_install_open()
    CODE:
        SAVE_AND_REPLACE_PP_IF_UNSET(real_pp_open, OP_OPEN, Perl_pp_overload_open, OP_OPEN_replace_mutex);

void
_install_sysopen()
    CODE:
        SAVE_AND_REPLACE_PP_IF_UNSET(real_pp_sysopen, OP_SYSOPEN, Perl_pp_overload_sysopen, OP_SYSOPEN_replace_mutex);