perf scripts python: exported-sql-viewer.py: Add 'About' dialog box

With support for Python 2 or 3 and PySide 1 or 2 (Qt 4 or 5), it is
useful to see what versions are in use. Add an 'About' dialog box that
displays Python, PySide, Qt and database server (SQLite or PostgreSQL)
version numbers.

Committer testing:

  $ python ~acme/libexec/perf-core/scripts/python/exported-sql-viewer.py ~/c/adrian.hunter/simple-retpoline.db

  Then go to 'Help', then 'About', select all the lines with the mouse
  press 'Control+C', then, on the same terminal press control+shift+V
  which shows my current environment:

Python version:     2.7.16
PySide version:     1
Qt version:         4.8.7
SQLite version:     3.26.0
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190503120828.25326-7-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/scripts/python/exported-sql-viewer.py

@@ -2913,6 +2913,60 @@ class HelpOnlyWindow(QMainWindow):
 
 		self.setCentralWidget(self.text)
 
+# PostqreSQL server version
+
+def PostqreSQLServerVersion(db):
+	query = QSqlQuery(db)
+	QueryExec(query, "SELECT VERSION()")
+	if query.next():
+		v_str = query.value(0)
+		v_list = v_str.strip().split(" ")
+		if v_list[0] == "PostgreSQL" and v_list[2] == "on":
+			return v_list[1]
+		return v_str
+	return "Unknown"
+
+# SQLite version
+
+def SQLiteVersion(db):
+	query = QSqlQuery(db)
+	QueryExec(query, "SELECT sqlite_version()")
+	if query.next():
+		return query.value(0)
+	return "Unknown"
+
+# About dialog
+
+class AboutDialog(QDialog):
+
+	def __init__(self, glb, parent=None):
+		super(AboutDialog, self).__init__(parent)
+
+		self.setWindowTitle("About Exported SQL Viewer")
+		self.setMinimumWidth(300)
+
+		pyside_version = "1" if pyside_version_1 else "2"
+
+		text = "<pre>"
+		text += "Python version:     " + sys.version.split(" ")[0] + "\n"
+		text += "PySide version:     " + pyside_version + "\n"
+		text += "Qt version:         " + qVersion() + "\n"
+		if glb.dbref.is_sqlite3:
+			text += "SQLite version:     " + SQLiteVersion(glb.db) + "\n"
+		else:
+			text += "PostqreSQL version: " + PostqreSQLServerVersion(glb.db) + "\n"
+		text += "</pre>"
+
+		self.text = QTextBrowser()
+		self.text.setHtml(text)
+		self.text.setReadOnly(True)
+		self.text.setOpenExternalLinks(True)
+
+		self.vbox = QVBoxLayout()
+		self.vbox.addWidget(self.text)
+
+		self.setLayout(self.vbox);
+
 # Font resize
 
 def ResizeFont(widget, diff):
@@ -3010,6 +3064,7 @@ class MainWindow(QMainWindow):
 
 		help_menu = menu.addMenu("&Help")
 		help_menu.addAction(CreateAction("&Exported SQL Viewer Help", "Helpful information", self.Help, self, QKeySequence.HelpContents))
+		help_menu.addAction(CreateAction("&About Exported SQL Viewer", "About this application", self.About, self))
 
 	def Try(self, fn):
 		win = self.mdi_area.activeSubWindow()
@@ -3095,6 +3150,10 @@ class MainWindow(QMainWindow):
 	def Help(self):
 		HelpWindow(self.glb, self)
 
+	def About(self):
+		dialog = AboutDialog(self.glb, self)
+		dialog.exec_()
+
 # XED Disassembler
 
 class xed_state_t(Structure):