Add initial Blink-side support for the Screen Orientation API

Source/modules/screen_orientation/ScreenOrientation.cpp

Index: Source/modules/screen_orientation/ScreenOrientation.cpp
diff --git a/Source/modules/screen_orientation/ScreenOrientation.cpp b/Source/modules/screen_orientation/ScreenOrientation.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7cb981aaf34670e8a07165a7a2a63ca11e8e523d
--- /dev/null
+++ b/Source/modules/screen_orientation/ScreenOrientation.cpp
@@ -0,0 +1,218 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "ScreenOrientation.h"
+
+#include "core/frame/Frame.h"
+#include "core/frame/Screen.h"
+#include "core/page/ChromeClient.h"
+#include "modules/screen_orientation/ScreenOrientationClient.h"
+#include "modules/screen_orientation/ScreenOrientationController.h"
+
+namespace WebCore {
+
+ScreenOrientation::ScreenOrientation(Screen* screen)
+    : DOMWindowProperty(screen->frame())
+    , PageLifecycleObserver(page())
+    , ActiveDOMObject(frame() ? frame()->document() : 0)

[abarth-chromium, 2014/02/15 18:44:27]

What are the consequences of passing 0 to ActiveDOMObject here?  Presumably
we'll never get the stop notification, which would be bad.

+    , m_screen(screen)
+    , m_orientationLockTimer(this, &ScreenOrientation::orientationLockTimerFired)
+    , m_lockedOrientations(OrientationAny)
+{
+    ScreenOrientationController* controller = ScreenOrientationController::from(page());
+    if (controller)
+        controller->addObserver(this);
+}
+
+ScreenOrientation::~ScreenOrientation()
+{
+}
+
+const char* ScreenOrientation::supplementName()
+{
+    return "ScreenOrientation";
+}
+
+void ScreenOrientation::orientationLockTimerFired(Timer<ScreenOrientation>*)
+{
+    ScreenOrientationClient* client = ScreenOrientationController::clientFrom(page());
+    if (!client)
+        return;
+
+    client->lockOrientation(m_lockedOrientations);
+}
+
+void ScreenOrientation::didCommitLoad(Frame*)
+{
+    // New page loaded, unlock screen orientation.
+    unlockOrientation();
+}

[abarth-chromium, 2014/02/15 18:44:27]

Is this object a Frame-lifetime object or a Document-lifetime object?  You're
mixing up concepts from both.  I suspect it ought to be a Document-lifetime
object, which means you shouldn't do any processing when loads commit.

+
+void ScreenOrientation::willDestroyGlobalObjectInFrame()
+{
+    m_screen = 0;
+    DOMWindowProperty::willDestroyGlobalObjectInFrame();
+}
+
+void ScreenOrientation::willDetachGlobalObjectFromFrame()
+{
+    m_screen = 0;
+    DOMWindowProperty::willDetachGlobalObjectFromFrame();
+}

[abarth-chromium, 2014/02/15 18:44:27]

These don't make much sense.  We're a supplement of m_screen, which means we're
owned by m_screen.

+
+void ScreenOrientation::stop()
+{
+    ScreenOrientationController* controller = ScreenOrientationController::from(page());
+    if (controller)
+        controller->removeObserver(this);

[abarth-chromium, 2014/02/15 18:44:27]

What are the consequences of |controller| being zero here?  Won't we fail to
unregister ourselves?

+}
+
+Page* ScreenOrientation::page() const
+{
+    return frame() ? frame()->page() : 0;
+}
+
+ScreenOrientation* ScreenOrientation::from(Screen* screen)
+{
+    ScreenOrientation* supplement = static_cast<ScreenOrientation*>(Supplement<Screen>::from(screen, supplementName()));
+    if (!supplement) {
+        ASSERT(screen);
+        supplement = new ScreenOrientation(screen);
+        supplement->suspendIfNeeded();
+        provideTo(screen, supplementName(), adoptPtr(supplement));
+    }
+    return supplement;
+}
+
+struct ScreenOrientationInfo {
+    const AtomicString& name;
+    ScreenOrientationValues orientation;
+};
+
+static ScreenOrientationInfo* allowedOrientationsMap(unsigned& length)
+{
+    DEFINE_STATIC_LOCAL(const AtomicString, portrait, ("portrait", AtomicString::ConstructFromLiteral));
+    DEFINE_STATIC_LOCAL(const AtomicString, portraitPrimary, ("portrait-primary", AtomicString::ConstructFromLiteral));
+    DEFINE_STATIC_LOCAL(const AtomicString, portraitSecondary, ("portrait-secondary", AtomicString::ConstructFromLiteral));
+    DEFINE_STATIC_LOCAL(const AtomicString, landscape, ("landscape", AtomicString::ConstructFromLiteral));
+    DEFINE_STATIC_LOCAL(const AtomicString, landscapePrimary, ("landscape-primary", AtomicString::ConstructFromLiteral));
+    DEFINE_STATIC_LOCAL(const AtomicString, landscapeSecondary, ("landscape-secondary", AtomicString::ConstructFromLiteral));
+
+    static ScreenOrientationInfo orientationMap[] = {
+        { portrait, OrientationPortrait },
+        { portraitPrimary, OrientationPortraitPrimary },
+        { portraitSecondary, OrientationPortraitSecondary },
+        { landscape, OrientationLandscape },
+        { landscapePrimary, OrientationLandscapePrimary },
+        { landscapeSecondary, OrientationLandscapeSecondary }
+    };
+    length = WTF_ARRAY_LENGTH(orientationMap);
+    return orientationMap;
+}
+
+const AtomicString& ScreenOrientation::orientationToString(ScreenOrientationValue orientation)
+{
+    unsigned length = 0;
+    ScreenOrientationInfo* orientationMap = allowedOrientationsMap(length);
+    for (unsigned i = 0; i < length; ++i) {
+        if (orientationMap[i].orientation == orientation)
+            return orientationMap[i].name;
+    }
+    // We do no handle OrientationInvalid and OrientationAny but this is fine because screen.orientation
+    // should never return these and WebScreenOrientation does not define those values.
+    ASSERT_NOT_REACHED();
+    return nullAtom;
+}
+
+ScreenOrientationValues ScreenOrientation::stringToOrientationValues(const AtomicString& orientation)
+{
+    unsigned length = 0;
+    ScreenOrientationInfo* orientationMap = allowedOrientationsMap(length);
+    for (unsigned i = 0; i < length; ++i) {
+        if (orientationMap[i].name == orientation)
+            return orientationMap[i].orientation;
+    }
+    return OrientationInvalid;
+}
+
+const AtomicString& ScreenOrientation::orientation(Screen* screen)
+{
+    ScreenOrientation* screenOrientation = ScreenOrientation::from(screen);
+    ASSERT(screenOrientation);
+
+    ScreenOrientationController* controller = ScreenOrientationController::from(screenOrientation->page());
+    if (!controller)
+        return orientationToString(OrientationPortraitPrimary);
+
+    return orientationToString(controller->orientation());
+}
+
+bool ScreenOrientation::lockOrientation(Screen* screen, const Vector<String>& orientationsVector)
+{
+    ScreenOrientationValues orientations = OrientationInvalid;
+
+    for (unsigned i = 0; i < orientationsVector.size(); ++i) {
+        ScreenOrientationValues inputOrientation = stringToOrientationValues(AtomicString(orientationsVector[i]));
+        if (inputOrientation == OrientationInvalid)
+            return false;
+        orientations |= inputOrientation;
+    }
+
+    if (!orientations)
+        return false;
+
+    ScreenOrientation* screenOrientation = ScreenOrientation::from(screen);
+    ASSERT(screenOrientation);
+    screenOrientation->lockOrientationAsync(orientations);
+    return true;
+}
+
+bool ScreenOrientation::lockOrientation(Screen* screen, const AtomicString& orientationString)
+{
+    ScreenOrientationValues orientation = stringToOrientationValues(orientationString);
+    if (!orientation)
+        return false;
+
+    ScreenOrientation* screenOrientation = ScreenOrientation::from(screen);
+    ASSERT(screenOrientation);
+    screenOrientation->lockOrientationAsync(orientation);
+    return true;
+}
+
+void ScreenOrientation::lockOrientationAsync(ScreenOrientationValues orientations)
+{
+    ASSERT(!(orientations & OrientationInvalid));
+
+    m_lockedOrientations = orientations;
+    if (!m_orientationLockTimer.isActive())
+        m_orientationLockTimer.startOneShot(0);
+}
+
+void ScreenOrientation::unlockOrientation(Screen* screen)
+{
+    ScreenOrientation* screenOrientation = ScreenOrientation::from(screen);
+    ASSERT(screenOrientation);
+    screenOrientation->unlockOrientation();
+}
+
+void ScreenOrientation::unlockOrientation()
+{
+    if (m_lockedOrientations == OrientationAny)
+        return; // Not currently locked.
+
+    m_lockedOrientations = OrientationAny;
+
+    ScreenOrientationClient* client = ScreenOrientationController::clientFrom(page());
+    if (client)
+        client->unlockOrientation();
+}
+
+void ScreenOrientation::orientationChanged()
+{
+    if (m_screen)
+        m_screen->dispatchEvent(Event::create(EventTypeNames::orientationchange));
+}
+
+} // namespace WebCore