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+@* Web Views in Typica.
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+
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+\noindent Typica makes extensive use of web views. All printing is currently
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+handled by generating HTML with the required information, loading it into a web
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+view, and using the print capabilities provided there. Reports are provided by
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+running SQL queries, generating HTML, and displaying the results in a web view.
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+Even the program'@q'@>s about window is primarily a web view.
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+
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+In order to simplify the implementation of certain features, we subclass
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+|QWebView| and provide some additional functionality.
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+
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+@(webview.h@>=
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+#include <QWebView>
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+#include <QFile>
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+#include <QMessageBox>
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+#include <QDesktopServices>
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+#include <QPrinter>
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+#include <QPrintDialog>
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+#include <QWebFrame>
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+#include <QWebElement>
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+
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+#ifndef TypicaWebViewHeader
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+#define TypicaWebViewHeader
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+
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+class TypicaWebView : public QWebView
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+{
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+ Q_OBJECT
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+ public:
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+ TypicaWebView();
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+ Q_INVOKABLE void load(const QString &url);
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+ Q_INVOKABLE void print();
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+ Q_INVOKABLE void setHtml(const QString &html, const QUrl &baseUrl = QUrl());
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+ Q_INVOKABLE void setContent(QIODevice *device);
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+ Q_INVOKABLE QString saveXml();
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+ signals:
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+ void scriptLinkClicked(const QString &link);
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+ private slots:
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+ void linkDelegate(const QUrl &url);
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+};
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+
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+#endif
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+
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+@ The implementation is in a separate file.
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+
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+@(webview.cpp@>=
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+#include "webview.h"
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+
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+@<TypicaWebView implementation@>@;
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+
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+@ In the constructor we set up our link delegation policy.
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+
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+@<TypicaWebView implementation@>=
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+TypicaWebView::TypicaWebView() : QWebView()
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+{
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+ page()->setLinkDelegationPolicy(QWebPage::DelegateExternalLinks);
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+ connect(page(), SIGNAL(linkClicked(QUrl)), this, SLOT(linkDelegate(QUrl)));
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+}
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+
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+@ When a link is clicked, one of three things may happen. Certain reserved URLs
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+will trigger an immediate event which is just handled internally without
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+providing any kind of external notification. URLs that start with
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+|"typica://script/"| will produce a signal containing the rest of the URL. This
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+is intended for script code to intercept, interpret, and update the web view
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+with the requested information. Everything else is passed to |QDesktopServices|
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+which will defer to system-wide preferences for how to handle different link
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+and file types.
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+
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+@<TypicaWebView implementation@>=
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+void TypicaWebView::linkDelegate(const QUrl &url)
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+{
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+ if(url.scheme() == "typica")
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+ {
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+ QString address(url.toEncoded());
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+ @<Detect and handle special links@>@;
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+ @<Detect and handle script links@>@;
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+ }
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+ else
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+ {
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+ QDesktopServices::openUrl(url);
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+ }
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+}
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+
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+@ Currently the only special link is |"typica://aboutqt"| which brings up
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+information about the Qt framework. This is used in the About Typica window.
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+
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+@<Detect and handle special links@>=
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+if(address == "typica://aboutqt")
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+{
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+ QMessageBox::aboutQt(this);
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+ return;
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+}
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+
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+@ Script links split the link data to simplify interpretation in script code.
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+
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+@<Detect and handle script links@>=
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+if(address.startsWith("typica://script/"))
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+{
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+ emit scriptLinkClicked(address.remove(0, 16));
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+ return;
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+}
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+
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+@ There is a limited set of functions that should be available to the host
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+environment which are not declared as slots or otherwise have some missing
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+functionality in the base class. In some cases the new functions can be
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+distinguished by signature.
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+
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+@<TypicaWebView implementation@>=
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+void TypicaWebView::load(const QString &url)
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+{
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+ QWebView::load(QUrl(url));
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+}
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+
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+void TypicaWebView::print()
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+{
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+ QPrinter *printer = new QPrinter(QPrinter::HighResolution);
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+ QPrintDialog printDialog(printer, NULL);
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+ if(printDialog.exec() == QDialog::Accepted)
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+ {
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+ QWebView::print(printer);
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+ }
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+}
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+
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+void TypicaWebView::setHtml(const QString &html, const QUrl &baseUrl)
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+{
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+ QWebView::setHtml(html, baseUrl);
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+}
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+
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+void TypicaWebView::setContent(QIODevice *device)
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+{
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+ device->reset();
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+ QByteArray content = device->readAll();
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+ QWebView::setContent(content, "application/xhtml+xml");
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+}
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+
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+QString TypicaWebView::saveXml()
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+{
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+ return page()->currentFrame()->documentElement().toOuterXml();
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+}
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+
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+@ Web views are exposed to the host environment in the usual manner.
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+
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+@<Set up the scripting engine@>=
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+constructor = engine->newFunction(constructWebView);
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+value = engine->newQMetaObject(&TypicaWebView::staticMetaObject, constructor);
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+engine->globalObject().setProperty("WebView", value);
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+
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+@ Now that |QWebView| is subclassed, all of the features that we need should
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+be available through the meta-object system automatically.
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+
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+@<Functions for scripting@>=
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+QScriptValue constructWebView(QScriptContext *, QScriptEngine *engine)
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+{
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+ QScriptValue object = engine->newQObject(new TypicaWebView);
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+ setQWebViewProperties(object, engine);
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+ return object;
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+}
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+
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+void setQWebViewProperties(QScriptValue value, QScriptEngine *engine)
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+{
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+ setQWidgetProperties(value, engine);
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+}
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+
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+@ It is also possible to create these web views from the XML portion of the
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+configuration document. A function is provided to add a new view to a box
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+layout.
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+
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+@<Functions for scripting@>=
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+void addWebViewToLayout(QDomElement element, QStack<QWidget *> *,
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+ QStack<QLayout *> *layoutStack)
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+{
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+ TypicaWebView *view = new TypicaWebView;
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+ if(element.hasAttribute("id"))
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+ {
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+ view->setObjectName(element.attribute("id"));
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+ }
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+ QBoxLayout *layout = qobject_cast<QBoxLayout *>(layoutStack->top());
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+ layout->addWidget(view);
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+}
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+
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+@ Prototypes must be provided for these functions.
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+
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+@<Function prototypes for scripting@>=
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+QScriptValue constructWebView(QScriptContext *context, QScriptEngine *engine);
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+void setQWebViewProperties(QScriptValue value, QScriptEngine *engine);
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+void addWebViewToLayout(QDomElement element, QStack<QWidget *> *widgetStack,
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+ QStack<QLayout *> *layoutStack);
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+
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+@ Finally, we must include our new header in |"typica.cpp"|.
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+
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+@<Header files to include@>=
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+#include "webview.h"
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+
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Neal Wilson
преди 11 години