Tooling: Add a command line application for QML preview

The "qmlpreview" tool connects to the preview service, and watches any
file successfully served to the application. If any of those files
change on disk, the new file is sent and the root component is reloaded.

Task-number: QDS-181
Change-Id: I2266167ada6e463c11be0d7548c2b96e31e79839
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

5 files changed, 399 insertions, 0 deletions

diff --git a/tools/qmlpreview/main.cpp b/tools/qmlpreview/main.cpp
new file mode 100644
index 0000000000..c7a32da258
--- /dev/null
+++ b/tools/qmlpreview/main.cpp
@@ -0,0 +1,36 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the tools applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qmlpreviewapplication.h"
+
+int main(int argc, char *argv[])
+{
+    QmlPreviewApplication app(argc, argv);
+    app.parseArguments();
+    return app.exec();
+}
diff --git a/tools/qmlpreview/qmlpreview.pro b/tools/qmlpreview/qmlpreview.pro
new file mode 100644
index 0000000000..7d443b5f6c
--- /dev/null
+++ b/tools/qmlpreview/qmlpreview.pro
@@ -0,0 +1,13 @@
+QT = network core qmldebug-private
+CONFIG += no_import_scan
+
+SOURCES += \
+    main.cpp \
+    qmlpreviewapplication.cpp
+
+HEADERS += \
+    qmlpreviewapplication.h
+
+QMAKE_TARGET_DESCRIPTION = QML Preview
+
+load(qt_tool)
diff --git a/tools/qmlpreview/qmlpreviewapplication.cpp b/tools/qmlpreview/qmlpreviewapplication.cpp
new file mode 100644
index 0000000000..618769502c
--- /dev/null
+++ b/tools/qmlpreview/qmlpreviewapplication.cpp
@@ -0,0 +1,266 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qmlpreviewapplication.h"
+
+#include <QtCore/QStringList>
+#include <QtCore/QTextStream>
+#include <QtCore/QProcess>
+#include <QtCore/QTimer>
+#include <QtCore/QDateTime>
+#include <QtCore/QFileInfo>
+#include <QtCore/QDebug>
+#include <QtCore/QDir>
+#include <QtCore/QCommandLineParser>
+#include <QtCore/QTemporaryFile>
+#include <QtCore/QUrl>
+
+QmlPreviewApplication::QmlPreviewApplication(int &argc, char **argv) :
+    QCoreApplication(argc, argv),
+    m_verbose(false),
+    m_connectionAttempts(0)
+{
+    m_connection.reset(new QQmlDebugConnection);
+    m_qmlPreviewClient.reset(new QQmlPreviewClient(m_connection.data()));
+    m_connectTimer.setInterval(1000);
+
+    m_loadTimer.setInterval(100);
+    m_loadTimer.setSingleShot(true);
+    connect(&m_loadTimer, &QTimer::timeout, this, [this]() {
+        m_qmlPreviewClient->triggerLoad(QUrl());
+    });
+
+    connect(&m_connectTimer, &QTimer::timeout, this, &QmlPreviewApplication::tryToConnect);
+    connect(m_connection.data(), &QQmlDebugConnection::connected, &m_connectTimer, &QTimer::stop);
+
+    connect(m_qmlPreviewClient.data(), &QQmlPreviewClient::error,
+            this, &QmlPreviewApplication::logError);
+    connect(m_qmlPreviewClient.data(), &QQmlPreviewClient::request,
+            this, &QmlPreviewApplication::serveRequest);
+
+    connect(&m_watcher, &QFileSystemWatcher::fileChanged,
+            this, &QmlPreviewApplication::sendFile);
+    connect(&m_watcher, &QFileSystemWatcher::directoryChanged,
+            this, &QmlPreviewApplication::sendDirectory);
+}
+
+QmlPreviewApplication::~QmlPreviewApplication()
+{
+    if (m_process && m_process->state() != QProcess::NotRunning) {
+        logStatus("Terminating process ...");
+        m_process->disconnect();
+        m_process->terminate();
+        if (!m_process->waitForFinished(1000)) {
+            logStatus("Killing process ...");
+            m_process->kill();
+        }
+    }
+}
+
+void QmlPreviewApplication::parseArguments()
+{
+    setApplicationName(QLatin1String("qmlpreview"));
+    setApplicationVersion(QLatin1String(qVersion()));
+
+    QCommandLineParser parser;
+    parser.setSingleDashWordOptionMode(QCommandLineParser::ParseAsLongOptions);
+    parser.setOptionsAfterPositionalArgumentsMode(QCommandLineParser::ParseAsPositionalArguments);
+
+    parser.setApplicationDescription(QChar::LineFeed + tr(
+        "The QML Preview tool watches QML and JavaScript files on disk and updates\n"
+        "the application live with any changes. The application to be previewed\n"
+        "has to enable QML debugging. See the Qt Creator documentation on how to do\n"
+        "this for different Qt versions."));
+
+    QCommandLineOption verbose(QStringList() << QLatin1String("verbose"),
+                               tr("Print debugging output."));
+    parser.addOption(verbose);
+
+    parser.addHelpOption();
+    parser.addVersionOption();
+
+    parser.addPositionalArgument(QLatin1String("program"),
+                                 tr("The program to be started and profiled."),
+                                 QLatin1String("[program]"));
+    parser.addPositionalArgument(QLatin1String("parameters"),
+                                 tr("Parameters for the program to be started."),
+                                 QLatin1String("[parameters...]"));
+
+    parser.process(*this);
+
+    QTemporaryFile file;
+    if (file.open())
+        m_socketFile = file.fileName();
+
+    if (parser.isSet(verbose))
+        m_verbose = true;
+
+    m_programArguments = parser.positionalArguments();
+    if (!m_programArguments.isEmpty())
+        m_programPath = m_programArguments.takeFirst();
+
+    if (m_programPath.isEmpty()) {
+        logError(tr("You have to specify a program to start."));
+        parser.showHelp(2);
+    }
+}
+
+int QmlPreviewApplication::exec()
+{
+    QTimer::singleShot(0, this, &QmlPreviewApplication::run);
+    return QCoreApplication::exec();
+}
+
+void QmlPreviewApplication::run()
+{
+    logStatus(QString("Listening on %1 ...").arg(m_socketFile));
+    m_connection->startLocalServer(m_socketFile);
+    m_process.reset(new QProcess(this));
+    QStringList arguments;
+    arguments << QString("-qmljsdebugger=file:%1,block,services:QmlPreview").arg(m_socketFile);
+    arguments << m_programArguments;
+
+    m_process->setProcessChannelMode(QProcess::MergedChannels);
+    connect(m_process.data(), &QIODevice::readyRead,
+            this, &QmlPreviewApplication::processHasOutput);
+    connect(m_process.data(), static_cast<void(QProcess::*)(int)>(&QProcess::finished),
+            this, [this](int){ processFinished(); });
+    logStatus(QString("Starting '%1 %2' ...").arg(m_programPath, arguments.join(QLatin1Char(' '))));
+    m_process->start(m_programPath, arguments);
+    if (!m_process->waitForStarted()) {
+        logError(QString("Could not run '%1': %2").arg(m_programPath, m_process->errorString()));
+        exit(1);
+    }
+    m_connectTimer.start();
+}
+
+void QmlPreviewApplication::tryToConnect()
+{
+    Q_ASSERT(!m_connection->isConnected());
+    ++m_connectionAttempts;
+
+    if (m_verbose && !(m_connectionAttempts % 5)) {// print every 5 seconds
+        logError(QString("No connection received on %1 for %2 seconds ...")
+                 .arg(m_socketFile).arg(m_connectionAttempts));
+    }
+}
+
+void QmlPreviewApplication::processHasOutput()
+{
+    Q_ASSERT(m_process);
+    while (m_process->bytesAvailable()) {
+        QTextStream out(stderr);
+        out << m_process->readAll();
+    }
+}
+
+void QmlPreviewApplication::processFinished()
+{
+    Q_ASSERT(m_process);
+    int exitCode = 0;
+    if (m_process->exitStatus() == QProcess::NormalExit) {
+        logStatus(QString("Process exited (%1).").arg(m_process->exitCode()));
+    } else {
+        logError("Process crashed!");
+        exitCode = 3;
+    }
+    exit(exitCode);
+}
+
+void QmlPreviewApplication::logError(const QString &error)
+{
+    QTextStream err(stderr);
+    err << "Error: " << error << endl;
+}
+
+void QmlPreviewApplication::logStatus(const QString &status)
+{
+    if (!m_verbose)
+        return;
+    QTextStream err(stderr);
+    err << status << endl;
+}
+
+void QmlPreviewApplication::serveRequest(const QString &path)
+{
+    QFileInfo info(path);
+
+    if (info.isDir()) {
+        m_qmlPreviewClient->sendDirectory(path, QDir(path).entryList());
+        m_watcher.addPath(path);
+    } else {
+        QFile file(path);
+        if (file.open(QIODevice::ReadOnly)) {
+            m_qmlPreviewClient->sendFile(path, file.readAll());
+            m_watcher.addPath(path);
+
+            // Also watch the directory, because editors will rather replace a file than change it.
+            // Therefore when the file changes, we can't read it, but when the file is re-added we can
+            // see that from the directory changing.
+            m_watcher.addPath(info.absolutePath());
+        } else {
+            logStatus(QString("Could not open file %1 for reading: %2").arg(path)
+                      .arg(file.errorString()));
+            m_qmlPreviewClient->sendError(path);
+        }
+    }
+}
+
+bool QmlPreviewApplication::sendFile(const QString &path)
+{
+    QFile file(path);
+    if (file.open(QIODevice::ReadOnly)) {
+        m_qmlPreviewClient->sendFile(path, file.readAll());
+        m_pendingFiles.removeAll(path);
+        // Defer the Load, because files tend to change multiple times in a row.
+        m_loadTimer.start();
+        return true;
+    }
+    if (!m_pendingFiles.contains(path))
+        m_pendingFiles.append(path);
+    logStatus(QString("Could not open file %1 for reading: %2").arg(path).arg(file.errorString()));
+    return false;
+}
+
+void QmlPreviewApplication::sendDirectory(const QString &path)
+{
+    m_qmlPreviewClient->sendDirectory(path, QDir(path).entryList());
+    for (auto it = m_pendingFiles.begin(); it != m_pendingFiles.end();) {
+        const QString filePath = *it;
+        QFile file(filePath);
+        if (file.open(QIODevice::ReadOnly)) {
+            logStatus(QString("Sending replaced file %1.").arg(filePath));
+            m_qmlPreviewClient->sendFile(filePath, file.readAll());
+            m_watcher.addPath(filePath);
+            it = m_pendingFiles.erase(it);
+        } else {
+            ++it;
+        }
+    }
+    m_loadTimer.start();
+}
diff --git a/tools/qmlpreview/qmlpreviewapplication.h b/tools/qmlpreview/qmlpreviewapplication.h
new file mode 100644
index 0000000000..eb363b0eb6
--- /dev/null
+++ b/tools/qmlpreview/qmlpreviewapplication.h
@@ -0,0 +1,83 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QMLPREVIEWAPPLICATION_H
+#define QMLPREVIEWAPPLICATION_H
+
+#include <private/qqmlpreviewclient_p.h>
+#include <private/qqmldebugconnection_p.h>
+
+#include <QtCore/qcoreapplication.h>
+#include <QtCore/qprocess.h>
+#include <QtCore/qtimer.h>
+#include <QtCore/qfilesystemwatcher.h>
+
+#include <QtNetwork/qabstractsocket.h>
+
+class QmlPreviewApplication : public QCoreApplication
+{
+    Q_OBJECT
+public:
+    QmlPreviewApplication(int &argc, char **argv);
+    ~QmlPreviewApplication();
+
+    void parseArguments();
+    int exec();
+
+private:
+    void run();
+    void tryToConnect();
+    void processHasOutput();
+    void processFinished();
+
+    void logError(const QString &error);
+    void logStatus(const QString &status);
+
+    void serveRequest(const QString &request);
+    bool sendFile(const QString &path);
+    void sendDirectory(const QString &path);
+
+    QString m_programPath;
+    QStringList m_programArguments;
+    QScopedPointer<QProcess> m_process;
+    bool m_verbose;
+
+    QString m_socketFile;
+
+    QScopedPointer<QQmlDebugConnection> m_connection;
+    QScopedPointer<QQmlPreviewClient> m_qmlPreviewClient;
+    QFileSystemWatcher m_watcher;
+
+    QTimer m_loadTimer;
+    QTimer m_connectTimer;
+    uint m_connectionAttempts;
+
+    QStringList m_pendingFiles;
+};
+
+#endif // QMLPREVIEWAPPLICATION_H
diff --git a/tools/tools.pro b/tools/tools.pro
index d35605b5ae..22544d60d3 100644
--- a/tools/tools.pro
+++ b/tools/tools.pro
@@ -15,6 +15,7 @@ qtConfig(qml-devtools) {
 
     qtConfig(qml-devtools): SUBDIRS += qmllint
     qtConfig(qml-profiler): SUBDIRS += qmlprofiler
+    qtConfig(qml-preview): SUBDIRS += qmlpreview
 
     qtHaveModule(quick) {
         !static: {