Add Qt syntax highlighting.

Makefile

@@ -142,6 +142,7 @@ doccheck:
 	  linkcheck/gui/properties.py \
 	  linkcheck/gui/settings.py \
 	  linkcheck/gui/statistics.py \
+	  linkcheck/gui/syntax.py \
 	  linkcheck/gui/updater.py \
 	  linkcheck/gui/urlmodel.py \
 	  linkcheck/gui/urlsave.py \

doc/changelog.txt

@@ -1,5 +1,9 @@
 6.9 "" (released xx.xx.2011)
 
+Features:
+- gui: Add syntax highlighting for Qt editor in case QScintilla
+  is not installed.
+
 
 6.8 "Ghost in the shell" (released 26.4.2011)
 

linkcheck/gui/editor.py

@@ -50,13 +50,7 @@ class EditorWindow (QtGui.QDialog, Ui_EditorDialog):
     def setContentType (self, content_type):
         """Choose a lexer according to given content type."""
         lexerclass = ContentTypeLexers.get(content_type.lower())
-        if lexerclass:
-            lexer = lexerclass()
-            lexer.setFont(self.editor.font())
-            self.editor.setLexer(lexer)
-        else:
-            # use no styling
-            self.editor.setLexer()
+        self.editor.highlight(lexerclass)
 
     def setText (self, text, line=1, col=1):
         """Set editor text and jump to given line and column."""

linkcheck/gui/editor_qsci.py

@@ -97,3 +97,13 @@ class Editor (Qsci.QsciScintilla):
         # folding margin colors (foreground,background)
         self.setFoldMarginColors(QtGui.QColor("#f5f5dc"),
                                  QtGui.QColor("#aaaaaa"))
+
+    def highlight (self, lexerclass):
+        """Set syntax highlighter."""
+        if lexerclass:
+            lexer = lexerclass()
+            lexer.setFont(self.font())
+            self.setLexer(lexer)
+        else:
+            # use no styling
+            self.setLexer()

linkcheck/gui/editor_qt.py

@@ -18,9 +18,14 @@
 Text editor implemented with Qt
 """
 from PyQt4 import QtGui, QtCore
+from . import syntax
 
-# Empty lexer dictionary indicating no support for syntax highlighting
-ContentTypeLexers = {}
+# Map MIME type to QSyntaxHighlighter class
+ContentTypeLexers = {
+    "text/html": syntax.HtmlHighlighter,
+    "application/xml": syntax.XmlHighlighter,
+    "text/plain+ini": syntax.IniHighlighter,
+}
 
 class LineNumberArea (QtGui.QWidget):
     """Display line numbers."""
@@ -50,9 +55,12 @@ class Editor (QtGui.QPlainTextEdit):
         self.updateLineNumberAreaWidth(0)
         self.highlightCurrentLine()
 
-    def setLexer (self):
-        """Does nothing."""
-        pass
+    def highlight (self, lexerclass):
+        """Set syntax highlighter."""
+        if lexerclass:
+            self.lexer = lexerclass(self.document())
+        else:
+            self.lexer = None
 
     def setText (self, text):
         """Set editor text."""

linkcheck/gui/syntax.py

@@ -0,0 +1,83 @@
+# syntax.py
+
+from PyQt4 import QtCore, QtGui
+
+
+def format(color, style=''):
+    """Return a QTextCharFormat with the given attributes."""
+    format = QtGui.QTextCharFormat()
+    format.setForeground(getattr(QtCore.Qt, color))
+    if 'bold' in style:
+        format.setFontWeight(QtGui.QFont.Bold)
+    if 'italic' in style:
+        format.setFontItalic(True)
+    return format
+
+
+class Highlighter (QtGui.QSyntaxHighlighter):
+    """Base class for all highlighters."""
+
+    def __init__ (self, document):
+        """Initialize rules and styles."""
+        super(Highlighter, self).__init__(document)
+        self.rules = []
+        self.styles = {}
+
+    def highlightBlock(self, text):
+        """Highlight a text block."""
+        for expression, format in self.rules:
+            # get first match
+            index = expression.indexIn(text)
+            while index >= 0:
+                length = expression.matchedLength()
+                self.setFormat(index, length, format)
+                # jump to next match
+                index = expression.indexIn(text, index + length)
+        self.setCurrentBlockState(0)
+
+    def addRule (self, pattern, style):
+        """Add a rule pattern with given style."""
+        self.rules.append((QtCore.QRegExp(pattern), self.styles[style]))
+
+
+class XmlHighlighter (Highlighter):
+    """XML syntax highlighter."""
+
+    def __init__(self, document):
+        """Set XML syntax rules."""
+        super(XmlHighlighter, self).__init__(document)
+        self.styles.update({
+            'keyword': format('darkBlue'),
+            'attribute': format('darkGreen'),
+            'comment': format('darkYellow'),
+            'string': format('darkMagenta'),
+        })
+        # keywords
+        for reg in ('/>', '>', '<!?[a-zA-Z0-9_]+'):
+            self.addRule(reg, 'keyword')
+        # attributes
+        self.addRule(r"\b[A-Za-z0-9_]+(?=\s*\=)", 'attribute')
+        # double-quoted string, possibly containing escape sequences
+        self.addRule(r'"[^"\\]*(\\.[^"\\]*)*"', 'string')
+        # single-quoted string, possibly containing escape sequences
+        self.addRule(r"'[^'\\]*(\\.[^'\\]*)*'", 'string')
+        # comments
+        self.addRule(r"<!--[^>]*-->", 'comment')
+
+# Treat HTML as XML
+HtmlHighlighter = XmlHighlighter
+
+class IniHighlighter (Highlighter):
+    """INI syntax highlighter."""
+
+    def __init__(self, document):
+        """Set INI syntax rules."""
+        super(IniHighlighter, self).__init__(document)
+        self.styles.update({
+            'section': format('darkBlue'),
+            'property': format('darkGreen'),
+            'comment': format('darkYellow'),
+        })
+        self.addRule(r'\b\[[a-zA-Z0-9_]+\]\b', 'section')
+        self.addRule(r'\b[a-zA-Z0-9_]+\](?=\s*\=)', 'property')
+        self.addRule(r'#[^\n]*', 'comment')