Added WebPerl module

(Note that this commit is a squash of previous development on WebPerl,
see `git log v5.28.0..bc78e33 ext/WebPerl`
and `git log 483e830..e70d909`)

.gitignore

@@ -212,4 +212,11 @@ GTAGS
 /lib/WebPerl.pm
 /emperl.*
 /nodeperl_dev.*
+# Modules we import
+/ext/Cpanel-JSON-XS/
+/ext/Devel-StackTrace/
+/ext/Future/
+/lib/Cpanel/
+/lib/Future.pm
+/lib/Future/
 

ext/WebPerl/.gitignore

@@ -0,0 +1,8 @@
+!/Makefile.PL
+/MYMETA.*
+/*.bs
+/*.o
+/blib/
+/Makefile
+/WebPerl.c
+/pm_to_blib

ext/WebPerl/Makefile.PL

@@ -0,0 +1,10 @@
+use 5.026;
+use ExtUtils::MakeMaker;
+WriteMakefile(
+	NAME              => 'WebPerl',
+	VERSION_FROM      => 'lib/WebPerl.pm',
+	AUTHOR            => 'Hauke D <haukex@zero-g.net>',
+	LICENSE           => 'perl',
+	INC               => '-I.',
+	CCFLAGS           => '-fPIC',
+);

ext/WebPerl/WebPerl.xs

@@ -0,0 +1,129 @@
+#define PERL_NO_GET_CONTEXT
+#include "EXTERN.h"
+#include "perl.h"
+#include "XSUB.h"
+
+/** ***** WebPerl - http://webperl.zero-g.net *****
+ * 
+ * Copyright (c) 2018 Hauke Daempfling (haukex@zero-g.net)
+ * at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB),
+ * Berlin, Germany, http://www.igb-berlin.de
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the same terms as Perl 5 itself: either the GNU General Public
+ * License as published by the Free Software Foundation (either version 1,
+ * or, at your option, any later version), or the "Artistic License" which
+ * comes with Perl 5.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the licenses for details.
+ * 
+ * You should have received a copy of the licenses along with this program.
+ * If not, see http://perldoc.perl.org/index-licence.html
+**/
+
+#include <emscripten.h>
+
+extern int emperl_end_perl();
+
+// a simple wrapper for eval_pv
+const char* webperl_eval_perl(const char* code) {
+	SV *rv = eval_pv(code, TRUE);
+	return SvOK(rv) ? SvPV_nolen(rv) : NULL;
+}
+
+// STRLEN=MEM_SIZE=Size_t, and the code below (accessing HEAP32) currently assumes this is 4 bytes
+#if Size_t_size!=4
+#error "Unsupported Size_t"
+#endif
+
+EM_JS(const char*, js_eval_js, (const char* codestr, STRLEN ilen, int wantrv, STRLEN* olen), {
+	var out = "";
+	try {
+		var code = my_UTF8ArrayToString(codestr, ilen);
+		if (Perl.trace) console.debug("Perl: eval", code, "- wantrv",wantrv);
+		var rv = eval(code);
+		if (wantrv==0)       // js() was called in void context, so we don't need
+			rv = undefined;  // any handling of the return value, especially GlueTable stuff!
+		// In the future, we could switch to using the supposedly faster Function constructor,
+		// but we need to make sure callers know this because of the differences (e.g. in accessing global JS objects)
+		//var rv = Function( '"use strict"; return (' + code + ')' )();
+		switch (typeof rv) {
+			case "undefined":
+				out = "U";
+				break;
+			case "boolean":
+				out = (rv ? "1" : "0") + "B";
+				break;
+			case "number":
+				out = String(rv) + "N";
+				break;
+			case "string":
+				out = rv + "S";
+				break;
+			case "function":
+				out = Perl.glue(rv) + "F";
+				break;
+			case "object":
+				if (rv==null)
+					out = "U";
+				else if (Array.isArray(rv))
+					out = Perl.glue(rv) + "A";
+				else
+					out = Perl.glue(rv) + "O";
+				break;
+			default:
+				console.warn("js_get_js: unsupported return type",rv);
+				out = (typeof rv) + "X";
+				break;
+		}
+	}
+	catch (ex) {
+		out = ex + "E";
+	}
+	if (Perl.trace) console.debug("Perl: returning", out);
+	var lengthBytes = lengthBytesUTF8(out); // without null terminator
+	HEAP32[olen>>2] = lengthBytes;
+	var stringOnWasmHeap = _malloc(lengthBytes+1); // plus null terminator
+	stringToUTF8(out, stringOnWasmHeap, lengthBytes+1); // not yet sure why +1 is needed here
+	return stringOnWasmHeap;
+});
+
+MODULE = WebPerl		PACKAGE = WebPerl
+PROTOTYPES: DISABLE
+
+int
+refcount(ref)
+	SV *ref
+	CODE:
+		RETVAL = SvROK(ref) ? SvREFCNT(SvRV(ref)) : -1;
+	OUTPUT:
+		RETVAL
+
+SV *
+xs_eval_js(code, wantrv)
+	SV*	code
+	int	wantrv
+	INIT:
+		STRLEN ilen;
+		STRLEN olen;
+		char *codestr;
+		const char *out;
+	CODE:
+		codestr = SvPV(code, ilen);
+		out = js_eval_js(codestr, ilen, wantrv, &olen);
+		RETVAL = newSVpvn_utf8(out, olen, 1);
+		free((void*)out);
+	OUTPUT:
+		RETVAL
+
+int
+end_perl()
+	CODE:
+		// TODO Later: end_perl() doesn't cause Module.onExit to be called, right?
+		RETVAL = emperl_end_perl();
+	OUTPUT:
+		RETVAL
+