Dukky: Support console logging better

Add a polyfill for Array.from(), and fix the console formatter so that
it won't keep exploding.  This should improve matters in the tests.

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>

content/handlers/javascript/duktape/Makefile

@@ -4,7 +4,10 @@
 # Included by javascript/Makefile
 #
 
-content/handlers/javascript/duktape/dukky.c: $(OBJROOT)/duktape/binding.h $(OBJROOT)/duktape/generics.js.inc
+content/handlers/javascript/duktape/dukky.c: \
+	$(OBJROOT)/duktape/binding.h \
+	$(OBJROOT)/duktape/generics.js.inc \
+	$(OBJROOT)/duktape/polyfill.js.inc
 
 BINDINGS := $(wildcard content/handlers/javascript/duktape/*.bnd)
 
@@ -15,6 +18,13 @@ $(OBJROOT)/duktape/generics.js.inc: content/handlers/javascript/duktape/generics
 	$(Q)xxd -i $< $@.tmp
 	$(Q)sed -e 's/content_handlers_javascript_duktape_generics_js/generics_js/' $@.tmp > $@
 
+# Generator for the C include representing the polyfill.js
+$(OBJROOT)/duktape/polyfill.js.inc: content/handlers/javascript/duktape/polyfill.js
+	$(Q)$(MKDIR) -p $(OBJROOT)/duktape
+	$(VQ)echo "     XXD: $<"
+	$(Q)xxd -i $< $@.tmp
+	$(Q)sed -e 's/content_handlers_javascript_duktape_polyfill_js/polyfill_js/' $@.tmp > $@
+
 # ensure genbind generates debugging files
 GBFLAGS+=-D
 

content/handlers/javascript/duktape/dukky.c

@@ -39,6 +39,7 @@
 
 #include "duktape/binding.h"
 #include "duktape/generics.js.inc"
+#include "duktape/polyfill.js.inc"
 
 #include "duktape.h"
 #include "dukky.h"
@@ -681,6 +682,25 @@ jsobject *js_newcompartment(jscontext *ctx, void *win_priv, void *doc_priv)
 	duk_push_object(CTX);
 	duk_put_global_string(CTX, EVENT_MAGIC);
 
+	/* Now load the polyfills */
+	/* ... */
+	duk_push_string(CTX, "polyfill.js");
+	/* ..., polyfill.js */
+	if (duk_pcompile_lstring_filename(CTX, DUK_COMPILE_EVAL,
+					  (const char *)polyfill_js, polyfill_js_len) != 0) {
+		NSLOG(dukky, CRITICAL, "%s", duk_safe_to_string(CTX, -1));
+		NSLOG(dukky, CRITICAL, "Unable to compile polyfill.js, compartment aborted");
+		return NULL;
+	}
+	/* ..., (generics.js) */
+	if (dukky_pcall(CTX, 0, true) != 0) {
+		NSLOG(dukky, CRITICAL, "Unable to run polyfill.js, compartment aborted");
+		return NULL;
+	}
+	/* ..., result */
+	duk_pop(CTX);
+	/* ... */
+
 	/* Now load the NetSurf table in */
 	/* ... */
 	duk_push_string(CTX, "generics.js");

content/handlers/javascript/duktape/generics.js

@@ -44,7 +44,7 @@ var NetSurf = {
 
 	const offset = target.search("%");
 
-	if (offset == -1 || offset >= target.length) {
+	if (offset == -1 || offset >= (target.length - 1)) {
 	    // We've a string, but the % either doesn't exist or is
 	    // at the end of it, so give up
 	    return Array.from(arguments);

content/handlers/javascript/duktape/polyfill.js

@@ -0,0 +1,85 @@
+/* Polyfiller for Duktape for NetSurf
+ *
+ * This JavaScript will be loaded into compartments before the generics
+ *
+ * We only care for the side-effects of this, be careful.
+ */
+
+// Production steps of ECMA-262, Edition 6, 22.1.2.1
+if (!Array.from) {
+  Array.from = (function () {
+    var toStr = Object.prototype.toString;
+    var isCallable = function (fn) {
+      return typeof fn === 'function' || toStr.call(fn) === '[object Function]';
+    };
+    var toInteger = function (value) {
+      var number = Number(value);
+      if (isNaN(number)) { return 0; }
+      if (number === 0 || !isFinite(number)) { return number; }
+      return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
+    };
+    var maxSafeInteger = Math.pow(2, 53) - 1;
+    var toLength = function (value) {
+      var len = toInteger(value);
+      return Math.min(Math.max(len, 0), maxSafeInteger);
+    };
+
+    // The length property of the from method is 1.
+    return function from(arrayLike/*, mapFn, thisArg */) {
+      // 1. Let C be the this value.
+      var C = this;
+
+      // 2. Let items be ToObject(arrayLike).
+      var items = Object(arrayLike);
+
+      // 3. ReturnIfAbrupt(items).
+      if (arrayLike == null) {
+        throw new TypeError('Array.from requires an array-like object - not null or undefined');
+      }
+
+      // 4. If mapfn is undefined, then let mapping be false.
+      var mapFn = arguments.length > 1 ? arguments[1] : void undefined;
+      var T;
+      if (typeof mapFn !== 'undefined') {
+        // 5. else
+        // 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
+        if (!isCallable(mapFn)) {
+          throw new TypeError('Array.from: when provided, the second argument must be a function');
+        }
+
+        // 5. b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+        if (arguments.length > 2) {
+          T = arguments[2];
+        }
+      }
+
+      // 10. Let lenValue be Get(items, "length").
+      // 11. Let len be ToLength(lenValue).
+      var len = toLength(items.length);
+
+      // 13. If IsConstructor(C) is true, then
+      // 13. a. Let A be the result of calling the [[Construct]] internal method 
+      // of C with an argument list containing the single item len.
+      // 14. a. Else, Let A be ArrayCreate(len).
+      var A = isCallable(C) ? Object(new C(len)) : new Array(len);
+
+      // 16. Let k be 0.
+      var k = 0;
+      // 17. Repeat, while k < len… (also steps a - h)
+      var kValue;
+      while (k < len) {
+        kValue = items[k];
+        if (mapFn) {
+          A[k] = typeof T === 'undefined' ? mapFn(kValue, k) : mapFn.call(T, kValue, k);
+        } else {
+          A[k] = kValue;
+        }
+        k += 1;
+      }
+      // 18. Let putStatus be Put(A, "length", len, true).
+      A.length = len;
+      // 20. Return A.
+      return A;
+    };
+  }());
+}