Stop destroying of invalid instances from crashing.

Extractor.xs

@@ -36,7 +36,7 @@ EXTRACTOR_loadConfigLibraries (prev, config)
 		const char *config
 	POSTCALL:
 		if (prev) {
-			perl_extractor_invalidate_object (ST(0));
+			perl_extractor_invalidate_object (ST (0));
 		}
 
 EXTRACTOR_ExtractorList *
@@ -45,7 +45,7 @@ EXTRACTOR_addLibrary (prev, library)
 		const char *library
 	POSTCALL:
 		if (prev) {
-			perl_extractor_invalidate_object (ST(0));
+			perl_extractor_invalidate_object (ST (0));
 		}
 
 EXTRACTOR_ExtractorList *
@@ -54,15 +54,15 @@ EXTRACTOR_addLibraryLast (prev, library)
 		const char *library
 	POSTCALL:
 		if (prev) {
-			perl_extractor_invalidate_object (ST(0));
+			perl_extractor_invalidate_object (ST (0));
 		}
 
 EXTRACTOR_ExtractorList *
 EXTRACTOR_removeLibrary (prev, library)
 		EXTRACTOR_ExtractorList *prev
 		const char *library
 	POSTCALL:
-		perl_extractor_invalidate_object (ST(0));
+		perl_extractor_invalidate_object (ST (0));
 
 void
 EXTRACTOR_getKeywords (extractor, data)
@@ -98,7 +98,7 @@ EXTRACTOR_getKeywords (extractor, data)
 
 void
 DESTROY (libraries)
-		EXTRACTOR_ExtractorList *libraries = perl_extractor_object_is_invalid($arg) ? NULL : ($type)perl_extractor_get_ptr_from_sv ($arg, "File::Extractor");
+		EXTRACTOR_ExtractorList *libraries = perl_extractor_object_is_invalid ($arg) ? NULL : ($type)perl_extractor_get_ptr_from_sv ($arg, "File::Extractor");
 	CODE:
 		if (libraries) {
 			EXTRACTOR_removeAll (libraries);

Makefile.PL

@@ -8,7 +8,8 @@ use inc::Module::Install;
 name 'File-Extractor';
 all_from 'lib/File/Extractor.pm';
 
-build_requires 'ExtUtils::PkgConfig' => 0;
+configure_requires 'ExtUtils::PkgConfig';
+
 build_requires 'IO::File' => 0;
 build_requires 'Test::Exception' => 0;
 build_requires 'Test::More' => 0;

perl_extractor.c

@@ -71,7 +71,7 @@ perl_extractor_invalidate_object (SV *obj) {
 	HV *hv;
 
 	hv = (HV *)SvRV (obj);
-	if (!hv_store (hv, "invalidated", 11, &PL_sv_yes, 0)) {
+	if (!hv_stores (hv, PERL_EXTRACTOR_INVALIDED, &PL_sv_yes)) {
 		croak ("failed to store invalidation flag");
 	}
 }
@@ -81,8 +81,14 @@ perl_extractor_object_is_invalid (SV *obj) {
 	HV *hv;
 	SV **val;
 
+	if (!obj || !SvOK (obj) || !SvROK (obj)
+	 || SvTYPE (SvRV (obj)) != SVt_PVHV
+	 || !mg_find (SvRV (obj), PERL_MAGIC_ext)) {
+		croak ("invalid object");
+	}
+
 	hv = (HV *)SvRV (obj);
-	val = hv_fetch(hv, "invalidated", 11, 0);
+	val = hv_fetchs (hv, PERL_EXTRACTOR_INVALIDED, 0);
 
 	if (!val || !*val) {
 		return 0;

perl_extractor.h

@@ -15,6 +15,8 @@
 
 #define EXTRACTOR_ExtractorList_or_null EXTRACTOR_ExtractorList
 
+#define PERL_EXTRACTOR_INVALIDED "invalidated"
+
 START_EXTERN_C
 
 SV *perl_extractor_new_sv_from_ptr (void *ptr, const char *class);