Introduce mkspec for web assembly

The mkspec and corresponding configuration adjustments make it possible to
build/link the modules in qtbase and run simple applications using the
stock emscripten compiler. Tested cross-compiled (-xplatform emscripten),
but theoretically possible as a native build as well (requiring some
binfmt_misc settings on Linux to run the resulting JS versions of host
tools with node)

*NOTE*: this currently requires passing -no-headersclean, as headersclean
crashes the compiler.

This was done outside of the wip/nacl branch because 1) we can use the new
configure system and 2) most of the nacl patches don't apply to emscripten
builds anyway.

As emscripten can be used to build for raw JavaScript engines (e.g. nodejs)
as well as web browsers, some differentiation between the compiler and the
GUI platform (HTML5) has been added. Furthermore, a hypothetical "html5"
QPA plugin has been referenced.

TODO:
  - fix headersclean option
  - decide if we should disable pthreads support, as it requires Firefox
    and an experimental flag (see
        https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer)
    ... leading to either QT_NO_THREAD or an alternate implementation
  - break up the unrelated changes better (e.g. separate double-conversion
    patch)
  - provide better application/lib support for building dynamic libraries
    (currently, building an app links in the actual bitcode instead, and
    the ports libs are linked into the app instead of the correct Qt lib)
  - possibly improve the configure tests rather than selectively disabling
    configuration options unsupported by emscripten but for which the
    config.tests pass
  - check all examples, testcases, modules in other repositories...
  - benchmark performance

Change-Id: I80cfa53605896ec8430df0b34bc1bce2c775d97f
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

1 files changed, 210 insertions, 0 deletions

diff --git a/src/plugins/platforms/html5/qhtml5eventtranslator.h b/src/plugins/platforms/html5/qhtml5eventtranslator.h
new file mode 100644
index 0000000000..b0ff1aa072
--- /dev/null
+++ b/src/plugins/platforms/html5/qhtml5eventtranslator.h
@@ -0,0 +1,210 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#ifndef QHTML5EVENTTRANSLATOR_H
+#define QHTML5EVENTTRANSLATOR_H
+
+#include <QObject>
+#include <QRect>
+#include <QtCore/QPoint>
+#include <emscripten/html5.h>
+#include "qhtml5window.h"
+
+QT_BEGIN_NAMESPACE
+
+class QWindow;
+
+class QHTML5EventTranslator : public QObject
+{
+    Q_OBJECT
+
+    enum KeyCode
+      {
+        // numpad
+        KeyNumPad0 = 0x60,
+        KeyNumPad1 = 0x61,
+        KeyNumPad2 = 0x62,
+        KeyNumPad3 = 0x63,
+        KeyNumPad4 = 0x64,
+        KeyNumPad5 = 0x65,
+        KeyNumPad6 = 0x66,
+        KeyNumPad7 = 0x67,
+        KeyNumPad8 = 0x68,
+        KeyNumPad9 = 0x69,
+        KeyMultiply = 0x6A,
+        KeyAdd = 0x6B,
+        KeySeparator = 0x6C,
+        KeySubtract = 0x6D,
+        KeyDecimal = 0x6E,
+        KeyDivide = 0x6F,
+        KeyMeta = 0x5B,
+        KeyMetaRight = 0x5C,
+        ////////
+        KeyClear = 0x90,
+        KeyEnter = 0xD,
+        KeyBackSpace = 0x08,
+        KeyCancel = 0x03,
+        KeyTab = 0x09,
+        KeyShift = 0x10,
+        KeyControl = 0x11,
+        KeyAlt = 0x12,
+        KeyPause = 0x13,
+        KeyCapsLock = 0x14,
+        KeyEscape = 0x1B,
+        KeySpace = 0x20,
+        KeyPageUp = 0x21,
+        KeyPageDown = 0x22,
+        KeyEnd = 0x23,
+        KeyHome = 0x24,
+        KeyLeft = 0x25,
+        KeyUp = 0x26,
+        KeyRight = 0x27,
+        KeyDown = 0x28,
+        KeyComma = 0xBC,
+        KeyPeriod = 0xBE,
+        KeySlash = 0xBF,
+        KeyZero = 0x30,
+        KeyOne = 0x31,
+        KeyTwo = 0x32,
+        KeyThree = 0x33,
+        KeyFour = 0x34,
+        KeyFive = 0x35,
+        KeySix = 0x36,
+        KeySeven = 0x37,
+        KeyEight = 0x38,
+        KeyNine = 0x39,
+        KeyBrightnessDown = 0xD8,
+        KeyBrightnessUp = 0xD9,
+        KeyMediaTrackPrevious = 0xB1,
+        KeyMediaPlayPause = 0xB3,
+        KeyMediaTrackNext = 0xB0,
+        KeyAudioVolumeMute = 0xAD,
+        KeyAudioVolumeDown = 0xAE,
+        KeyAudioVolumeUp = 0xAF,
+        KeySemiColon = 0xBA,
+        KeyEquals = 0xBB,
+        KeyMinus = 0xBD,
+        KeyA = 0x41,
+        KeyB = 0x42,
+        KeyC = 0x43,
+        KeyD = 0x44,
+        KeyE = 0x45,
+        KeyF = 0x46,
+        KeyG = 0x47,
+        KeyH = 0x48,
+        KeyI = 0x49,
+        KeyJ = 0x4A,
+        KeyK = 0x4B,
+        KeyL = 0x4C,
+        KeyM = 0x4D,
+        KeyN = 0x4E,
+        KeyO = 0x4F,
+        KeyP = 0x50,
+        KeyQ = 0x51,
+        KeyR = 0x52,
+        KeyS = 0x53,
+        KeyT = 0x54,
+        KeyU = 0x55,
+        KeyV = 0x56,
+        KeyW = 0x57,
+        KeyX = 0x58,
+        KeyY = 0x59,
+        KeyZ = 0x5A,
+        KeyOpenBracket = 0xDB,
+        KeyBackSlash = 0xDC,
+        KeyCloseBracket = 0xDD,
+        KeyF1 = 0x70,
+        KeyF2 = 0x71,
+        KeyF3 = 0x72,
+        KeyF4 = 0x73,
+        KeyF5 = 0x74,
+        KeyF6 = 0x75,
+        KeyF7 = 0x76,
+        KeyF8 = 0x77,
+        KeyF9 = 0x78,
+        KeyF10 = 0x79,
+        KeyF11 = 0x7A,
+        KeyF12 = 0x7B,
+        KeyDelete = 0x2E,
+        KeyNumLock = 0x90,
+        KeyScrollLock = 0x91,
+        KeyPrintScreen = 0x9A,
+        KeyInsert = 0x9B,
+        KeyHelp = 0x9C,
+        KeyBackQuote = 0xC0,
+        KeyQuote = 0xDE,
+        KeyFinal = 0x18,
+        KeyConvert = 0x1C,
+        KeyNonConvert = 0x1D,
+        KeyAccept = 0x1E,
+        KeyModeChange = 0x1F,
+        KeyKana = 0x15,
+        KeyKanji = 0x19,
+        KeyUndefined = 0x0
+      };
+
+public:
+
+    explicit QHTML5EventTranslator(QObject *parent = 0);
+
+    static int keyboard_cb(int eventType, const EmscriptenKeyboardEvent *keyEvent, void *userData);
+    static int mouse_cb(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
+    static int focus_cb(int eventType, const EmscriptenFocusEvent *focusEvent, void *userData);
+
+Q_SIGNALS:
+    void getWindowAt(const QPoint &point, QWindow **window);
+private:
+    static Qt::Key translateEmscriptKey(const EmscriptenKeyboardEvent *emscriptKey, bool *outAlphanumretic);
+    static QFlags<Qt::KeyboardModifier> translateKeyModifier(const EmscriptenKeyboardEvent *keyEvent);
+    static QFlags<Qt::KeyboardModifier> translateMouseModifier(const EmscriptenMouseEvent *mouseEvent);
+    static Qt::MouseButton translateMouseButton(unsigned short button);
+
+    void processMouse(int eventType, const EmscriptenMouseEvent *mouseEvent);
+
+private:
+    QWindow *draggedWindow;
+    QWindow *pressedWindow;
+    Qt::MouseButtons pressedButtons;
+
+    QHtml5Window::ResizeMode resizeMode;
+    QPoint resizePoint;
+    QRect resizeStartRect;
+};
+
+QT_END_NAMESPACE
+#endif // QHTML5EVENTTRANSLATOR_H