Bug 1606084 - ValueToSource should be able to handle wrapped objects. r=jwalden

Differential Revision: https://phabricator.services.mozilla.com/D60312

--HG--
extra : moz-landing-system : lando

js/public/Class.h

@@ -942,6 +942,7 @@ enum class ESClass {
   Arguments,
   Error,
   BigInt,
+  Function,  // Note: Only JSFunction objects.
 
   /** None of the above. */
   Other

js/src/jit-test/tests/basic/valuetosource.js

@@ -1,29 +1,31 @@
 // |jit-test| --disable-tosource
 
 const TEST_CASES = [
-    [undefined, "(void 0)"],
-    [null, "null"],
-    [true, "true"],
-    [Symbol("abc"), `Symbol("abc")`],
-    [15, "15"],
-    [-0, "-0"],
-    ["abc", `"abc"`],
-    [function a() { return 1; }, `(function a() { return 1; })`],
-    [[1, 2, 3], `[1, 2, 3]`],
-    [[1, {a: 0, b: 0}, 2], `[1, {a:0, b:0}, 2]`],
-    [{a: [1, 2, 3]}, `({a:[1, 2, 3]})`],
-    [new Error("msg", "file", 1), `(new Error("msg", "file", 1))`],
-    [new TypeError("msg", "file", 1), `(new TypeError("msg", "file", 1))`],
-    [new class X extends Error {
+    [`undefined`, "(void 0)"],
+    [`null`, "null"],
+    [`true`, "true"],
+    [`Symbol("abc")`, `Symbol("abc")`],
+    [`15`, "15"],
+    [`-0`, "-0"],
+    [`"abc"`, `"abc"`],
+    [`(function a() { return 1; })`, `(function a() { return 1; })`],
+    [`[1, 2, 3]`, `[1, 2, 3]`],
+    [`[1, {a: 0, b: 0}, 2]`, `[1, {a:0, b:0}, 2]`],
+    [`({a: [1, 2, 3]})`, `({a:[1, 2, 3]})`],
+    [`new Error("msg", "file", 1)`, `(new Error("msg", "file", 1))`],
+    [`new TypeError("msg", "file", 1)`, `(new TypeError("msg", "file", 1))`],
+    [`new class X extends Error {
         constructor() {
             super("msg", "file", 1);
             this.name = "X";
         }
-    }, `(new X("msg", "file", 1))`],
-    [/a(b)c/, `/a(b)c/`],
-    [/abc/gi, `/abc/gi`],
+    }`, `(new X("msg", "file", 1))`],
+    [`/a(b)c/`, `/a(b)c/`],
+    [`/abc/gi`, `/abc/gi`],
 ]
 
+let g = newGlobal({newCompartment: true});
 for (let [actual, expected] of TEST_CASES) {
-    assertEq(valueToSource(actual), expected);
+    assertEq(valueToSource(eval(actual)), expected);
+    assertEq(valueToSource(g.eval(actual)), expected);
 }

js/src/jsfriendapi.cpp

@@ -302,6 +302,8 @@ JS_FRIEND_API bool js::GetBuiltinClass(JSContext* cx, HandleObject obj,
     *cls = ESClass::Error;
   } else if (obj->is<BigIntObject>()) {
     *cls = ESClass::BigInt;
+  } else if (obj->is<JSFunction>()) {
+    *cls = ESClass::Function;
   } else {
     *cls = ESClass::Other;
   }

js/src/vm/StructuredClone.cpp

@@ -1722,6 +1722,7 @@ bool JSStructuredCloneWriter::startWrite(HandleValue v) {
       case ESClass::SetIterator:
       case ESClass::Arguments:
       case ESClass::Error:
+      case ESClass::Function:
         break;
 
       case ESClass::Other: {

js/src/vm/ToSource.cpp

@@ -12,12 +12,13 @@
 
 #include <stdint.h>  // uint32_t
 
-#include "jsfriendapi.h"  // CheckRecursionLimit
+#include "jsfriendapi.h"  // CheckRecursionLimit, GetBuiltinClass
 
 #include "builtin/Array.h"    // ArrayToSource
 #include "builtin/Boolean.h"  // BooleanToString
 #include "builtin/Object.h"   // ObjectToSource
 #include "gc/Allocator.h"     // CanGC
+#include "js/Class.h"         // ESClass
 #include "js/Symbol.h"        // SymbolCode, JS::WellKnownSymbolLimit
 #include "js/TypeDecls.h"  // Rooted{Function, Object, String, Value}, HandleValue, Latin1Char
 #include "js/Utility.h"         // UniqueChars
@@ -27,9 +28,8 @@
 #include "vm/ErrorObject.h"     // ErrorObject, ErrorToSource
 #include "vm/Interpreter.h"     // Call
 #include "vm/JSContext.h"       // JSContext
-#include "vm/JSFunction.h"      // JSFunction, FunctionToString
+#include "vm/JSFunction.h"      // JSFunction, fun_toStringHelper
 #include "vm/Printer.h"         // QuoteString
-#include "vm/RegExpObject.h"    // RegExpObject
 #include "vm/SelfHosting.h"     // CallSelfHostedFunction
 #include "vm/Stack.h"           // FixedInvokeArgs
 #include "vm/StringType.h"      // NewStringCopy{N,Z}, ToString
@@ -143,30 +143,35 @@ JSString* js::ValueToSource(JSContext* cx, HandleValue v) {
         return ToString<CanGC>(cx, v);
       }
 
-      if (obj->is<JSFunction>()) {
-        RootedFunction fun(cx, &obj->as<JSFunction>());
-        return FunctionToString(cx, fun, true);
+      ESClass cls;
+      if (!GetBuiltinClass(cx, obj, &cls)) {
+        return nullptr;
       }
 
-      if (obj->is<ArrayObject>()) {
-        return ArrayToSource(cx, obj);
-      }
+      // All ToSource functions must be able to handle wrapped objects!
+      switch (cls) {
+        case ESClass::Function:
+          return fun_toStringHelper(cx, obj, true);
 
-      if (obj->is<ErrorObject>()) {
-        return ErrorToSource(cx, obj);
-      }
+        case ESClass::Array:
+          return ArrayToSource(cx, obj);
 
-      if (obj->is<RegExpObject>()) {
-        FixedInvokeArgs<0> args(cx);
-        RootedValue rval(cx);
-        if (!CallSelfHostedFunction(cx, cx->names().RegExpToString, v, args,
-                                    &rval)) {
-          return nullptr;
+        case ESClass::Error:
+          return ErrorToSource(cx, obj);
+
+        case ESClass::RegExp: {
+          FixedInvokeArgs<0> args(cx);
+          RootedValue rval(cx);
+          if (!CallSelfHostedFunction(cx, cx->names().RegExpToString, v, args,
+                                      &rval)) {
+            return nullptr;
+          }
+          return ToString<CanGC>(cx, rval);
         }
-        return ToString<CanGC>(cx, rval);
-      }
 
-      return ObjectToSource(cx, obj);
+        default:
+          return ObjectToSource(cx, obj);
+      }
     }
 
     case JS::ValueType::PrivateGCThing: