[gjs] js: Replace JS_Add*Root with Rooted where trivial

[Philip Chimento <pchimento src gnome org>]

commit 9fb00a1ba3280802fd4786b8a2265246f3f6edc2
Author: Philip Chimento <philip endlessm com>
Date:   Thu Sep 29 19:25:01 2016 -0700

    js: Replace JS_Add*Root with Rooted where trivial
    
    Instead of using JS_AddFooRoot and JS_RemoveFooRoot on a value within the
    same scope, we should use JS::Rooted which is the mozjs31-style API.
    Besides being RAII and more readable, it will be required when mozjs API
    functions start taking JS::Handle parameters in mozjs31. This commit
    makes that change in places where it doesn't propagate into the API.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=742249

 gi/repo.cpp               |   24 ++++++++----------------
 gjs/byteArray.cpp         |   41 +++++++++++++----------------------------
 gjs/jsapi-util.cpp        |    7 ++-----
 modules/cairo-context.cpp |    6 ++----
 test/gjs-tests.cpp        |    7 ++-----
 5 files changed, 27 insertions(+), 58 deletions(-)
---
diff --git a/gi/repo.cpp b/gi/repo.cpp
index ce5afb0..ccd5ca8 100644
--- a/gi/repo.cpp
+++ b/gi/repo.cpp
@@ -96,13 +96,11 @@ resolve_namespace_object(JSContext  *context,
     char *version;
     JSObject *override;
     JS::Value result;
-    JSObject *gi_namespace = NULL;
-    bool ret = false;
 
-    JS_BeginRequest(context);
+    JSAutoRequest ar(context);
 
     if (!get_version_for_ns(context, repo_obj, ns_id, &version))
-        goto out;
+        return false;
 
     repo = g_irepository_get_default();
 
@@ -115,7 +113,7 @@ resolve_namespace_object(JSContext  *context,
 
         g_error_free(error);
         g_free(version);
-        goto out;
+        return false;
     }
 
     g_free(version);
@@ -124,8 +122,7 @@ resolve_namespace_object(JSContext  *context,
      * with the given namespace name, pointing to that namespace
      * in the repo.
      */
-    gi_namespace = gjs_create_ns(context, ns_name);
-    JS_AddObjectRoot(context, &gi_namespace);
+    JS::RootedObject gi_namespace(context, gjs_create_ns(context, ns_name));
 
     /* Define the property early, to avoid reentrancy issues if
        the override module looks for namespaces that import this */
@@ -142,19 +139,14 @@ resolve_namespace_object(JSContext  *context,
                                            0, /* argc */
                                            NULL, /* argv */
                                            &result))
-        goto out;
+        return false;
 
     gjs_debug(GJS_DEBUG_GNAMESPACE,
-              "Defined namespace '%s' %p in GIRepository %p", ns_name, gi_namespace, repo_obj);
+              "Defined namespace '%s' %p in GIRepository %p", ns_name,
+              gi_namespace.get(), repo_obj);
 
-    ret = true;
     gjs_schedule_gc_if_needed(context);
-
- out:
-    if (gi_namespace)
-        JS_RemoveObjectRoot(context, &gi_namespace);
-    JS_EndRequest(context);
-    return ret;
+    return true;
 }
 
 /*
diff --git a/gjs/byteArray.cpp b/gjs/byteArray.cpp
index e69eb85..7695463 100644
--- a/gjs/byteArray.cpp
+++ b/gjs/byteArray.cpp
@@ -578,15 +578,11 @@ from_string_func(JSContext *context,
     ByteArrayInstance *priv;
     char *encoding;
     bool encoding_is_utf8;
-    JSObject *obj;
-    bool retval = false;
+    JS::RootedObject obj(context, byte_array_new(context));
 
-    obj = byte_array_new(context);
     if (obj == NULL)
         return false;
 
-    JS_AddObjectRoot(context, &obj);
-
     priv = priv_from_js(context, obj);
     g_assert (priv != NULL);
 
@@ -597,12 +593,12 @@ from_string_func(JSContext *context,
     if (!argv[0].isString()) {
         gjs_throw(context,
                   "byteArray.fromString() called with non-string as first arg");
-        goto out;
+        return false;
     }
 
     if (argc > 1 && argv[1].isString()) {
         if (!gjs_string_to_utf8(context, argv[1], &encoding))
-            goto out;
+            return false;
 
         /* maybe we should be smarter about utf8 synonyms here.
          * doesn't matter much though. encoding_is_utf8 is
@@ -627,7 +623,7 @@ from_string_func(JSContext *context,
         if (!gjs_string_to_utf8(context,
                                 argv[0],
                                 &utf8))
-            goto out;
+            return false;
 
         g_byte_array_set_size(priv->array, 0);
         g_byte_array_append(priv->array, (guint8*) utf8, strlen(utf8));
@@ -641,7 +637,7 @@ from_string_func(JSContext *context,
 
         u16_chars = JS_GetStringCharsAndLength(context, argv[0].toString(), &u16_len);
         if (u16_chars == NULL)
-            goto out;
+            return false;
 
         error = NULL;
         encoded = g_convert((char*) u16_chars,
@@ -655,7 +651,7 @@ from_string_func(JSContext *context,
         if (encoded == NULL) {
             /* frees the GError */
             gjs_throw_g_error(context, error);
-            goto out;
+            return false;
         }
 
         g_byte_array_set_size(priv->array, 0);
@@ -665,11 +661,7 @@ from_string_func(JSContext *context,
     }
 
     argv.rval().setObject(*obj);
-
-    retval = true;
- out:
-    JS_RemoveObjectRoot(context, &obj);
-    return retval;
+    return true;
 }
 
 /* fromArray() function implementation */
@@ -682,15 +674,11 @@ from_array_func(JSContext *context,
     ByteArrayInstance *priv;
     guint32 len;
     guint32 i;
-    JSObject *obj;
-    bool ret = false;
+    JS::RootedObject obj(context, byte_array_new(context));
 
-    obj = byte_array_new(context);
     if (obj == NULL)
         return false;
 
-    JS_AddObjectRoot(context, &obj);
-
     priv = priv_from_js(context, obj);
     g_assert (priv != NULL);
 
@@ -701,13 +689,13 @@ from_array_func(JSContext *context,
     if (!JS_IsArrayObject(context, &argv[0].toObject())) {
         gjs_throw(context,
                   "byteArray.fromArray() called with non-array as first arg");
-        goto out;
+        return false;
     }
 
     if (!JS_GetArrayLength(context, &argv[0].toObject(), &len)) {
         gjs_throw(context,
                   "byteArray.fromArray() can't get length of first array arg");
-        goto out;
+        return false;
     }
 
     g_byte_array_set_size(priv->array, len);
@@ -721,23 +709,20 @@ from_array_func(JSContext *context,
             /* this means there was an exception, while elem.isUndefined()
              * means no element found
              */
-            goto out;
+            return false;
         }
 
         if (elem.isUndefined())
             continue;
 
         if (!gjs_value_to_byte(context, elem, &b))
-            goto out;
+            return false;
 
         g_array_index(priv->array, guint8, i) = b;
     }
 
-    ret = true;
     argv.rval().setObject(*obj);
- out:
-    JS_RemoveObjectRoot(context, &obj);
-    return ret;
+    return true;
 }
 
 static JSBool
diff --git a/gjs/jsapi-util.cpp b/gjs/jsapi-util.cpp
index c4c85fc..7a956ec 100644
--- a/gjs/jsapi-util.cpp
+++ b/gjs/jsapi-util.cpp
@@ -589,13 +589,12 @@ static bool
 log_and_maybe_keep_exception(JSContext  *context,
                              bool        keep)
 {
-    JS::Value exc = JS::UndefinedValue();
     bool retval = false;
 
     JS_BeginRequest(context);
 
-    JS_AddValueRoot(context, &exc);
-    if (!JS_GetPendingException(context, &exc))
+    JS::RootedValue exc(context, JS::UndefinedValue());
+    if (!JS_GetPendingException(context, exc.address()))
         goto out;
 
     JS_ClearPendingException(context);
@@ -611,8 +610,6 @@ log_and_maybe_keep_exception(JSContext  *context,
     retval = true;
 
  out:
-    JS_RemoveValueRoot(context, &exc);
-
     JS_EndRequest(context);
 
     return retval;
diff --git a/modules/cairo-context.cpp b/modules/cairo-context.cpp
index 8fca420..ed03cc1 100644
--- a/modules/cairo-context.cpp
+++ b/modules/cairo-context.cpp
@@ -566,17 +566,16 @@ setDash_func(JSContext *context,
 
     guint i;
     cairo_t *cr;
-    JSObject *dashes;
+    JS::RootedObject dashes(context);
     double offset;
     bool retval = false;
     guint len;
     GArray *dashes_c = NULL;
 
     if (!gjs_parse_call_args(context, "setDash", "of", argv,
-                        "dashes", &dashes, "offset", &offset))
+                        "dashes", dashes.address(), "offset", &offset))
         return false;
 
-    JS_AddObjectRoot(context, &dashes);
 
     if (!JS_IsArrayObject(context, dashes)) {
         gjs_throw(context, "dashes must be an array");
@@ -617,7 +616,6 @@ setDash_func(JSContext *context,
  out:
     if (dashes_c != NULL)
         g_array_free (dashes_c, true);
-    JS_RemoveObjectRoot(context, &dashes);
     return retval;
 }
 
diff --git a/test/gjs-tests.cpp b/test/gjs-tests.cpp
index 7c3837f..40e0ec5 100644
--- a/test/gjs-tests.cpp
+++ b/test/gjs-tests.cpp
@@ -168,7 +168,7 @@ gjstest_test_func_gjs_jsapi_util_error_throw(void)
     GjsUnitTestFixture fixture;
     JSContext *context;
     JSObject *global;
-    JS::Value exc, value, previous;
+    JS::Value exc, value;
     char *s = NULL;
     int strcmp_result;
 
@@ -200,8 +200,7 @@ gjstest_test_func_gjs_jsapi_util_error_throw(void)
         g_error("Exception has wrong message '%s'", s);
 
     /* keep this around before we clear it */
-    previous = exc;
-    JS_AddValueRoot(context, &previous);
+    JS::RootedValue previous(context, exc);
 
     JS_ClearPendingException(context);
 
@@ -221,8 +220,6 @@ gjstest_test_func_gjs_jsapi_util_error_throw(void)
     g_assert(!exc.isUndefined());
     g_assert(&exc.toObject() == &previous.toObject());
 
-    JS_RemoveValueRoot(context, &previous);
-
     JS_LeaveCompartment(context, oldCompartment);
     _gjs_unit_test_fixture_finish(&fixture);
 }