feat: check stylesheets declared in SVG

This enables checking of CSS declared in SVG inline `style`
element, as well as stylesheets declared in  `<?xml-stylesheet?>`
processing instructions.

Fix #1450

Author: rdeltour

src/main/java/com/adobe/epubcheck/css/CSSHandler.java

@@ -159,7 +159,7 @@ else if (uriOrString.getType() == CssConstruct.Type.STRING)
         }
         if (uri != null)
         {
-          resolveAndRegister(uri, line, col, atRule.toCssString(), Reference.Type.GENERIC);
+          resolveAndRegister(uri, line, col, atRule.toCssString(), Reference.Type.STYLESHEET);
         }
       }
     }
@@ -390,7 +390,10 @@ private void resolveAndRegister(String uriString, int line, int col, String cssC
         if (url != null && context.referenceRegistry.isPresent())
         {
           context.referenceRegistry.get().registerReference(url, type, getCorrectedEPUBLocation(line, col, cssContext));
-          if (context.isRemote(url))
+          // register that a remote resource was found
+          // no need to register a remote stylesheet, as these are disallowed
+          // and will be reported elsewhere
+          if (type != Reference.Type.STYLESHEET && context.isRemote(url))
           {
             detectedProperties.add(ITEM_PROPERTIES.REMOTE_RESOURCES);
           }

src/main/java/com/adobe/epubcheck/ops/OPSHandler.java

@@ -25,7 +25,10 @@
 import java.util.Locale;
 import java.util.Stack;
 
+import org.w3c.epubcheck.constants.MIMEType;
 import org.w3c.epubcheck.core.references.Reference;
+import org.w3c.epubcheck.core.references.Reference.Type;
+import org.xml.sax.SAXException;
 
 import com.adobe.epubcheck.api.EPUBLocation;
 import com.adobe.epubcheck.css.CSSChecker;
@@ -40,6 +43,8 @@
 import com.adobe.epubcheck.xml.model.XMLElement;
 
 import io.mola.galimatias.URL;
+import net.sf.saxon.trans.XPathException;
+import net.sf.saxon.tree.util.ProcInstParser;
 
 public class OPSHandler extends XMLHandler
 {
@@ -190,6 +195,10 @@ public void startElement()
     Reference.Type resourceType = Reference.Type.GENERIC;
     if (ns != null)
     {
+      if (name.equals("style"))
+      {
+        textNode = new StringBuilder();
+      }
       if (ns.equals("http://www.w3.org/2000/svg"))
       {
         if (name.equals("lineargradient") || name.equals("radialgradient")
@@ -246,10 +255,6 @@ else if (name.equals("link"))
         {
           checkLink();
         }
-        else if (name.equals("style"))
-        {
-          textNode = new StringBuilder();
-        }
         else if (name.equals("iframe"))
         {
           checkIFrame();
@@ -341,20 +346,21 @@ public void endElement()
 
     EPUBLocation currentLocation = elementLocationStack.pop();
 
-    if (EpubConstants.HtmlNamespaceUri.equals(ns))
+    if ("style".equals(name))
     {
-
-      if ("style".equals(name))
+      String style = textNode.toString();
+      if (style.length() > 0)
       {
-        String style = textNode.toString();
-        if (style.length() > 0)
-        {
-          this.hasCSS = true;
-          new CSSChecker(context, style, currentLocation.getLine(), false).check();
-        }
-        textNode = null;
+        this.hasCSS = true;
+        new CSSChecker(context, style, currentLocation.getLine(), false).check();
       }
-      else if ("table".equals(name))
+      textNode = null;
+    }
+
+    if (EpubConstants.HtmlNamespaceUri.equals(ns))
+    {
+
+      if ("table".equals(name))
       {
         if (tableDepth > 0)
         {
@@ -392,4 +398,39 @@ public void characters(char[] chars, int start, int length)
     }
   }
 
+  @Override
+  public void processingInstruction(String target, String data)
+    throws SAXException
+  {
+    super.processingInstruction(target, data);
+
+    // for SVG documents, parse 'xml-stylesheet' processing instructions
+    if (MIMEType.SVG.is(context.mimeType) && "xml-stylesheet".equals(target))
+    {
+      checkXMLStylesheetPI(data);
+    }
+  }
+
+  protected void checkXMLStylesheetPI(String data)
+  {
+    assert data != null;
+    try
+    {
+      String type = ProcInstParser.getPseudoAttribute(data, "type");
+      if (type == null || MIMEType.CSS.is(type))
+      {
+        String href = ProcInstParser.getPseudoAttribute(data, "href");
+        URL url = checkURL(href);
+        if (url != null)
+        {
+          hasCSS = true;
+          registerReference(url, Type.STYLESHEET);
+        }
+      }
+    } catch (XPathException e1)
+    {
+      // ignore invalid declaration, must have been reported earlier
+    }
+  }
+
 }

src/test/resources/epub3/03-resources/files/file-url-in-svg-content-error.svg

@@ -3,6 +3,9 @@
 	<head>
 		<meta charset="utf-8"/>
 		<title>Minimal EPUB</title>
+		<style>
+			@import url(file:example);
+		</style>
 	</head>
 	<body>
 		<h1>Loomings</h1>

src/test/resources/epub3/03-resources/files/file-url-in-xhtml-content-error.xhtml

@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" xml:lang="en" lang="en">
+	<head>
+		<meta charset="utf-8"/>
+		<title>Minimal Nav</title>
+	</head>
+	<body>
+		<nav epub:type="toc">
+			<ol>
+				<li><a href="content_001.svg">content 001</a></li>
+			</ol>
+		</nav>
+	</body>
+</html>

src/test/resources/epub3/03-resources/files/resources-remote-stylesheet-svg-import-error/EPUB/content_001.svg

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" xml:lang="en" unique-identifier="q">
+<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+  <dc:title id="title">Minimal EPUB 3.0</dc:title>
+  <dc:language>en</dc:language>
+  <dc:identifier id="q">NOID</dc:identifier>
+  <meta property="dcterms:modified">2017-06-14T00:00:01Z</meta>
+</metadata>
+<manifest>
+  <item id="content_001"  href="content_001.svg" media-type="image/svg+xml"/>
+  <item id="nav"  href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+</manifest>
+<spine>
+  <itemref idref="content_001" />
+</spine>
+</package>

src/test/resources/epub3/03-resources/files/resources-remote-stylesheet-svg-import-error/EPUB/nav.xhtml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+	<rootfiles>
+		<rootfile full-path="EPUB/package.opf" media-type="application/oebps-package+xml"/>
+	</rootfiles>
+</container>

src/test/resources/epub3/03-resources/files/resources-remote-stylesheet-svg-import-error/EPUB/package.opf

@@ -0,0 +1 @@
+application/epub+zip