Implement navigation to rules defined in stylesheets

src/calibre/gui2/tweak_book/editor/smart/__init__.py

@@ -25,3 +25,6 @@ class NullSmarts(object):
 
     def goto_sourceline(self, editor, sourceline, tags, attribute=None):
         return False
+
+    def get_inner_HTML(self, editor):
+        return None

src/calibre/gui2/tweak_book/editor/smart/css.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__ = 'GPL v3'
+__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
+
+from calibre.gui2.tweak_book.editor.smart import NullSmarts
+
+def find_rule(raw, rule_address):
+    import tinycss
+    parser = tinycss.make_parser()
+    sheet = parser.parse_stylesheet(raw)
+    rules = sheet.rules
+    ans = None, None
+    while rule_address:
+        try:
+            r = rules[rule_address[0]]
+        except IndexError:
+            return None, None
+        else:
+            ans = r.line, r.column
+        rule_address = rule_address[1:]
+        if rule_address:
+            rules = getattr(r, 'rules', ())
+    return ans
+
+class CSSSmarts(NullSmarts):
+    pass
+

src/calibre/gui2/tweak_book/editor/smart/html.py

@@ -383,3 +383,27 @@ class HTMLSmarts(NullSmarts):
         editor.setTextCursor(c)
         return found_tag
 
+    def get_inner_HTML(self, editor):
+        ''' Select the inner HTML of the current tag. Return a cursor with the
+        inner HTML selected or None. '''
+        c = editor.textCursor()
+        block = c.block()
+        offset = c.position() - block.position()
+        nblock, boundary = next_tag_boundary(block, offset)
+        if boundary.is_start:
+            # We are within the contents of a tag already
+            tag = find_closest_containing_tag(block, offset)
+        else:
+            # We are inside a tag definition < | >
+            if boundary.self_closing:
+                return None  # self closing tags have no inner html
+            tag = find_closest_containing_tag(nblock, boundary.offset + 1)
+        if tag is None:
+            return None
+        ctag = find_closing_tag(tag)
+        if ctag is None:
+            return None
+        c.setPosition(tag.end_block.position() + tag.end_offset + 1)
+        c.setPosition(ctag.start_block.position() + ctag.start_offset, c.KeepAnchor)
+        return c
+

src/calibre/gui2/tweak_book/editor/text.py

@@ -25,6 +25,7 @@ from calibre.gui2.tweak_book.editor.syntax.html import HTMLHighlighter, XMLHighl
 from calibre.gui2.tweak_book.editor.syntax.css import CSSHighlighter
 from calibre.gui2.tweak_book.editor.smart import NullSmarts
 from calibre.gui2.tweak_book.editor.smart.html import HTMLSmarts
+from calibre.gui2.tweak_book.editor.smart.css import CSSSmarts
 from calibre.spell.break_iterator import index_of
 from calibre.utils.icu import safe_chr, string_length
 
@@ -211,7 +212,7 @@ class TextEdit(PlainTextEdit):
         self.highlighter = get_highlighter(syntax)()
         self.highlighter.apply_theme(self.theme)
         self.highlighter.set_document(self.document())
-        sclass = {'html':HTMLSmarts, 'xml':HTMLSmarts}.get(syntax, None)
+        sclass = {'html':HTMLSmarts, 'xml':HTMLSmarts, 'css':CSSSmarts}.get(syntax, None)
         if sclass is not None:
             self.smarts = sclass(self)
         self.setPlainText(unicodedata.normalize('NFC', text))
@@ -755,3 +756,31 @@ class TextEdit(PlainTextEdit):
     def goto_sourceline(self, sourceline, tags, attribute=None):
         return self.smarts.goto_sourceline(self, sourceline, tags, attribute=attribute)
 
+    def get_tag_contents(self):
+        c = self.smarts.get_inner_HTML(self)
+        if c is not None:
+            return self.selected_text_from_cursor(c)
+
+    def goto_css_rule(self, rule_address, sourceline_address=None):
+        from calibre.gui2.tweak_book.editor.smart.css import find_rule
+        block = None
+        if self.syntax == 'css':
+            raw = unicode(self.toPlainText())
+            line, col = find_rule(raw, rule_address)
+            if line is not None:
+                block = self.document().findBlockByNumber(line - 1)
+        elif sourceline_address is not None:
+            sourceline, tags = sourceline_address
+            if self.goto_sourceline(sourceline, tags):
+                c = self.textCursor()
+                c.setPosition(c.position() + 1)
+                self.setTextCursor(c)
+                raw = self.get_tag_contents()
+                line, col = find_rule(raw, rule_address)
+                if line is not None:
+                    block = self.document().findBlockByNumber(c.blockNumber() + line - 1)
+
+        if block is not None and block.isValid():
+            c = self.textCursor()
+            c.setPosition(block.position() + col)
+            self.setTextCursor(c)

src/calibre/gui2/tweak_book/editor/widget.py

@@ -406,6 +406,12 @@ class Editor(QMainWindow):
     def goto_sourceline(self, *args, **kwargs):
         return self.editor.goto_sourceline(*args, **kwargs)
 
+    def goto_css_rule(self, *args, **kwargs):
+        return self.editor.goto_css_rule(*args, **kwargs)
+
+    def get_tag_contents(self, *args, **kwargs):
+        return self.editor.get_tag_contents(*args, **kwargs)
+
     def _nuke_word(self, dic, word, locale):
         if dic is None:
             dictionaries.ignore_word(word, locale)

src/calibre/gui2/tweak_book/live_css.py

@@ -412,4 +412,8 @@ class LiveCSS(QWidget):
         if data['type'] == 'inline':
             sourceline, tags = data['sourceline_address']
             editor.goto_sourceline(sourceline, tags, attribute='style')
+        elif data['type'] == 'sheet':
+            editor.goto_css_rule(data['rule_address'])
+        elif data['type'] == 'elem':
+            editor.goto_css_rule(data['rule_address'], sourceline_address=data['sourceline_address'])