Add host context pseudo class function

ph-css/src/main/java/com/helger/css/decl/CSSSelectorMemberHostContext.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2014-2022 Philip Helger (www.helger.com)
+ * philip[at]helger[dot]com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.helger.css.decl;
+
+import javax.annotation.Nonnegative;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
+
+import com.helger.commons.ValueEnforcer;
+import com.helger.commons.annotation.Nonempty;
+import com.helger.commons.hashcode.HashCodeGenerator;
+import com.helger.commons.string.ToStringGenerator;
+import com.helger.css.CSSSourceLocation;
+import com.helger.css.ECSSVersion;
+import com.helger.css.ICSSSourceLocationAware;
+import com.helger.css.ICSSVersionAware;
+import com.helger.css.ICSSWriterSettings;
+
+/**
+ * Represents a single, simple CSS selector as used for the ":host-context()" CSS pseudo
+ * class function.<br>
+ * Note: this class was completely redesigned for version 3.7.4
+ *
+ * @author Philip Helger
+ */
+@NotThreadSafe
+public class CSSSelectorMemberHostContext implements ICSSSelectorMember, ICSSVersionAware, ICSSSourceLocationAware
+{
+  private final CSSSelector m_aSelector;
+  private CSSSourceLocation m_aSourceLocation;
+
+  public CSSSelectorMemberHostContext (@Nonnull final CSSSelector aSimpleSelector)
+  {
+    ValueEnforcer.notNull (aSimpleSelector, "SimpleSelector");
+    m_aSelector = aSimpleSelector;
+  }
+
+  @Nonnull
+  public final CSSSelector getSelector ()
+  {
+    return m_aSelector;
+  }
+
+  @Nonnull
+  @Nonempty
+  public String getAsCSSString (@Nonnull final ICSSWriterSettings aSettings, @Nonnegative final int nIndentLevel)
+  {
+    aSettings.checkVersionRequirements (this);
+
+    final StringBuilder aSB = new StringBuilder (":host-context(");
+    aSB.append (m_aSelector.getAsCSSString (aSettings, 0));
+    return aSB.append (')').toString ();
+  }
+
+  @Nonnull
+  public ECSSVersion getMinimumCSSVersion ()
+  {
+    return ECSSVersion.CSS30;
+  }
+
+  @Nullable
+  public final CSSSourceLocation getSourceLocation ()
+  {
+    return m_aSourceLocation;
+  }
+
+  public final void setSourceLocation (@Nullable final CSSSourceLocation aSourceLocation)
+  {
+    m_aSourceLocation = aSourceLocation;
+  }
+
+  @Override
+  public boolean equals (final Object o)
+  {
+    if (o == this)
+      return true;
+    if (o == null || !getClass ().equals (o.getClass ()))
+      return false;
+    final CSSSelectorMemberHostContext rhs = (CSSSelectorMemberHostContext) o;
+    return m_aSelector.equals (rhs.m_aSelector);
+  }
+
+  @Override
+  public int hashCode ()
+  {
+    return new HashCodeGenerator (this).append (m_aSelector).getHashCode ();
+  }
+
+  @Override
+  public String toString ()
+  {
+    return new ToStringGenerator (null).append ("Selector", m_aSelector)
+                                       .appendIfNotNull ("SourceLocation", m_aSourceLocation)
+                                       .getToString ();
+  }
+}

ph-css/src/main/java/com/helger/css/handler/CSSNodeToDomainObject.java

@@ -285,6 +285,18 @@ private ICSSSelectorMember _createSelectorMember (final CSSNode aNode)
           return ret;
         }
 
+        if (ECSSNodeType.HOSTCONTEXT.isNode (aChildNode, m_eVersion))
+        {
+          final CSSSelector aSelector = new CSSSelector ();
+          final int nChildChildCount = aChildNode.jjtGetNumChildren ();
+          for (int j = 0; j < nChildChildCount; ++j)
+            aSelector.addMember (_createSelectorMember (aChildNode.jjtGetChild (j)));
+          final CSSSelectorMemberHostContext ret = new CSSSelectorMemberHostContext (aSelector);
+          if (m_bUseSourceLocation)
+            ret.setSourceLocation (aNode.getSourceLocation ());
+          return ret;
+        }
+
         if (ECSSNodeType.SLOTTED.isNode (aChildNode, m_eVersion))
         {
           final CSSSelector aSelector = new CSSSelector ();

ph-css/src/main/java/com/helger/css/handler/ECSSNodeType.java

@@ -58,6 +58,7 @@ public enum ECSSNodeType
   CLASS (ParserCSS30TreeConstants.JJTCLASS),
   PSEUDO (ParserCSS30TreeConstants.JJTPSEUDO),
   HOST (ParserCSS30TreeConstants.JJTHOST),
+  HOSTCONTEXT (ParserCSS30TreeConstants.JJTHOSTCONTEXT),
   SLOTTED (ParserCSS30TreeConstants.JJTSLOTTED),
   NEGATION (ParserCSS30TreeConstants.JJTNEGATION),
   ATTRIB (ParserCSS30TreeConstants.JJTATTRIB),

ph-css/src/main/jjtree/ParserCSS30.jjt

@@ -302,6 +302,7 @@ TOKEN :
                  | "-" <IDENT> "-calc(" >
 | < FUNCTION_NOT: ":not(" >
 | < FUNCTION_HOST: "host(" >
+| < FUNCTION_HOSTCONTEXT: "host-context(" >
 | < FUNCTION_SLOTTED: "slotted(" >
 | < FUNCTION_NTH: "nth-child("
                 | "nth-last-child("
@@ -1020,6 +1021,14 @@ void pseudoHost () #host : {}
   )*
 }
 
+void pseudoHostContext () #hostcontext : {}
+{
+  ( <S> )*
+  ( simpleSelectorSequence () 
+    ( <S> )*
+  )*
+}
+
 void pseudoSlotted () #slotted : {}
 {
   ( <S> )*
@@ -1039,6 +1048,9 @@ void pseudo() : {}
   | <FUNCTION_HOST> { jjtThis.appendText (token.image); }
     pseudoHost()
     <RROUND> // do not append because of expression!
+  | <FUNCTION_HOSTCONTEXT> { jjtThis.appendText (token.image); }
+    pseudoHostContext()
+    <RROUND> // do not append because of expression!
   | <FUNCTION_SLOTTED> { jjtThis.appendText (token.image); }
     pseudoSlotted()
     <RROUND> // do not append because of expression!

ph-css/src/test/resources/testfiles/css30/good/issue80.css

@@ -0,0 +1,23 @@
+/* Selects a shadow root host, only if it is
+   a descendant of the selector argument given */
+:host-context(h1) {
+  font-weight: bold;
+}
+
+:host-context(.main .article) {
+  font-weight: bold;
+}
+
+/* Changes paragraph text color from black to white when
+   a .dark-theme class is applied to the document body */
+p {
+  color: #000;
+}
+
+:host-context(body.dark-theme) p {
+  color: #fff;
+}
+
+:host-context([dir="rtl"]) {
+  float: right !important;
+}