Add m-esr52 at 52.6.0

1 files changed, 224 insertions, 0 deletions

diff --git a/js/src/jsapi-tests/testPersistentRooted.cpp b/js/src/jsapi-tests/testPersistentRooted.cpp
new file mode 100644
index 000000000..e765d8c7a
--- /dev/null
+++ b/js/src/jsapi-tests/testPersistentRooted.cpp
@@ -0,0 +1,224 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "js/Class.h"
+#include "jsapi-tests/tests.h"
+
+using namespace JS;
+
+struct BarkWhenTracedClass {
+    static int finalizeCount;
+    static int traceCount;
+
+    static const JSClass class_;
+    static void finalize(JSFreeOp* fop, JSObject* obj) { finalizeCount++; }
+    static void trace(JSTracer* trc, JSObject* obj) { traceCount++; }
+    static void reset() { finalizeCount = 0; traceCount = 0; }
+};
+
+int BarkWhenTracedClass::finalizeCount;
+int BarkWhenTracedClass::traceCount;
+
+static const JSClassOps BarkWhenTracedClassClassOps = {
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    BarkWhenTracedClass::finalize,
+    nullptr,
+    nullptr,
+    nullptr,
+    BarkWhenTracedClass::trace
+};
+
+const JSClass BarkWhenTracedClass::class_ = {
+    "BarkWhenTracedClass",
+    JSCLASS_FOREGROUND_FINALIZE,
+    &BarkWhenTracedClassClassOps
+};
+
+struct Kennel {
+    PersistentRootedObject obj;
+    Kennel() { }
+    explicit Kennel(JSContext* cx) : obj(cx) { }
+    Kennel(JSContext* cx, const HandleObject& woof) : obj(cx, woof) { }
+    void init(JSContext* cx, const HandleObject& woof) {
+        obj.init(cx, woof);
+    }
+    void clear() {
+        obj = nullptr;
+    }
+};
+
+// A function for allocating a Kennel and a barker. Only allocating
+// PersistentRooteds on the heap, and in this function, helps ensure that the
+// conservative GC doesn't find stray references to the barker. Ugh.
+MOZ_NEVER_INLINE static Kennel*
+Allocate(JSContext* cx)
+{
+    RootedObject barker(cx, JS_NewObject(cx, &BarkWhenTracedClass::class_));
+    if (!barker)
+        return nullptr;
+
+    return new Kennel(cx, barker);
+}
+
+// Do a GC, expecting |n| barkers to be finalized.
+static bool
+GCFinalizesNBarkers(JSContext* cx, int n)
+{
+    int preGCTrace = BarkWhenTracedClass::traceCount;
+    int preGCFinalize = BarkWhenTracedClass::finalizeCount;
+
+    JS_GC(cx);
+
+    return (BarkWhenTracedClass::finalizeCount == preGCFinalize + n &&
+            BarkWhenTracedClass::traceCount > preGCTrace);
+}
+
+// PersistentRooted instances protect their contents from being recycled.
+BEGIN_TEST(test_PersistentRooted)
+{
+    BarkWhenTracedClass::reset();
+
+    mozilla::UniquePtr<Kennel> kennel(Allocate(cx));
+    CHECK(kennel.get());
+
+    // GC should be able to find our barker.
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    kennel = nullptr;
+
+    // Now GC should not be able to find the barker.
+    JS_GC(cx);
+    CHECK(BarkWhenTracedClass::finalizeCount == 1);
+
+    return true;
+}
+END_TEST(test_PersistentRooted)
+
+// GC should not be upset by null PersistentRooteds.
+BEGIN_TEST(test_PersistentRootedNull)
+{
+    BarkWhenTracedClass::reset();
+
+    Kennel kennel(cx);
+    CHECK(!kennel.obj);
+
+    JS_GC(cx);
+    CHECK(BarkWhenTracedClass::finalizeCount == 0);
+
+    return true;
+}
+END_TEST(test_PersistentRootedNull)
+
+// Copy construction works.
+BEGIN_TEST(test_PersistentRootedCopy)
+{
+    BarkWhenTracedClass::reset();
+
+    mozilla::UniquePtr<Kennel> kennel(Allocate(cx));
+    CHECK(kennel.get());
+
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    // Copy construction! AMAZING!
+    mozilla::UniquePtr<Kennel> newKennel(new Kennel(*kennel));
+
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    kennel = nullptr;
+
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    newKennel = nullptr;
+
+    // Now that kennel and nowKennel are both deallocated, GC should not be
+    // able to find the barker.
+    JS_GC(cx);
+    CHECK(BarkWhenTracedClass::finalizeCount == 1);
+
+    return true;
+}
+END_TEST(test_PersistentRootedCopy)
+
+// Assignment works.
+BEGIN_TEST(test_PersistentRootedAssign)
+{
+    BarkWhenTracedClass::reset();
+
+    mozilla::UniquePtr<Kennel> kennel(Allocate(cx));
+    CHECK(kennel.get());
+
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    // Allocate a new, empty kennel.
+    mozilla::UniquePtr<Kennel> kennel2(new Kennel(cx));
+
+    // Assignment! ASTONISHING!
+    *kennel2 = *kennel;
+
+    // With both kennels referring to the same barker, it is held alive.
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    kennel2 = nullptr;
+
+    // The destination of the assignment alone holds the barker alive.
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    // Allocate a second barker.
+    kennel2 = mozilla::UniquePtr<Kennel>(Allocate(cx));
+    CHECK(kennel2.get());
+
+    *kennel = *kennel2;
+
+    // Nothing refers to the first kennel any more.
+    CHECK(GCFinalizesNBarkers(cx, 1));
+
+    kennel = nullptr;
+    kennel2 = nullptr;
+
+    // Now that kennel and kennel2 are both deallocated, GC should not be
+    // able to find the barker.
+    JS_GC(cx);
+    CHECK(BarkWhenTracedClass::finalizeCount == 2);
+
+    return true;
+}
+END_TEST(test_PersistentRootedAssign)
+
+static PersistentRootedObject gGlobalRoot;
+
+// PersistentRooted instances can initialized in a separate step to allow for global PersistentRooteds.
+BEGIN_TEST(test_GlobalPersistentRooted)
+{
+    BarkWhenTracedClass::reset();
+
+    CHECK(!gGlobalRoot.initialized());
+
+    {
+        RootedObject barker(cx, JS_NewObject(cx, &BarkWhenTracedClass::class_));
+        CHECK(barker);
+
+        gGlobalRoot.init(cx, barker);
+    }
+
+    CHECK(gGlobalRoot.initialized());
+
+    // GC should be able to find our barker.
+    CHECK(GCFinalizesNBarkers(cx, 0));
+
+    gGlobalRoot.reset();
+    CHECK(!gGlobalRoot.initialized());
+
+    // Now GC should not be able to find the barker.
+    JS_GC(cx);
+    CHECK(BarkWhenTracedClass::finalizeCount == 1);
+
+    return true;
+}
+END_TEST(test_GlobalPersistentRooted)