Bugzilla #45715: Break before (break-before) not respected on blocks nested in inlines.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@1334058 13f79535-47bb-0310-9956-ffa450edef68

8 files changed, 121 insertions, 31 deletions

diff --git a/src/java/org/apache/fop/layoutmgr/AbstractLayoutManager.java b/src/java/org/apache/fop/layoutmgr/AbstractLayoutManager.java
index d227b7060..0089f228f 100644
--- a/src/java/org/apache/fop/layoutmgr/AbstractLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/AbstractLayoutManager.java
@@ -41,8 +41,7 @@ import org.apache.fop.fo.flow.RetrieveMarker;
 /**
  * The base class for most LayoutManagers.
  */
-public abstract class AbstractLayoutManager extends AbstractBaseLayoutManager
-        implements Constants {
+public abstract class AbstractLayoutManager extends AbstractBaseLayoutManager implements Constants {
 
     /** logging instance */
     private static Log log = LogFactory.getLog(AbstractLayoutManager.class);
diff --git a/src/java/org/apache/fop/layoutmgr/BlockContainerLayoutManager.java b/src/java/org/apache/fop/layoutmgr/BlockContainerLayoutManager.java
index 8b656a753..adce89ac0 100644
--- a/src/java/org/apache/fop/layoutmgr/BlockContainerLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/BlockContainerLayoutManager.java
@@ -44,8 +44,8 @@ import org.apache.fop.traits.SpaceVal;
 /**
  * LayoutManager for a block-container FO.
  */
-public class BlockContainerLayoutManager extends BlockStackingLayoutManager
-                implements ConditionalElementListener {
+public class BlockContainerLayoutManager extends BlockStackingLayoutManager implements
+        ConditionalElementListener, BreakOpportunity {
 
     /**
      * logging instance
@@ -1043,6 +1043,11 @@ public class BlockContainerLayoutManager extends BlockStackingLayoutManager
         }
         return true;
     }
+
+    public int getBreakBefore() {
+        return BreakOpportunityHelper.getBreakBefore(this);
+    }
+
 }
 
 
diff --git a/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java b/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java
index 9c3639f93..03b2d380c 100644
--- a/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/BlockLayoutManager.java
@@ -43,8 +43,8 @@ import org.apache.fop.traits.SpaceVal;
 /**
  * LayoutManager for a block FO.
  */
-public class BlockLayoutManager extends BlockStackingLayoutManager
-            implements ConditionalElementListener {
+public class BlockLayoutManager extends BlockStackingLayoutManager implements ConditionalElementListener,
+        BreakOpportunity {
 
     /** logging instance */
     private static Log log = LogFactory.getLog(BlockLayoutManager.class);
@@ -504,4 +504,8 @@ public class BlockLayoutManager extends BlockStackingLayoutManager
         return true;
     }
 
+    public int getBreakBefore() {
+        return BreakOpportunityHelper.getBreakBefore(this);
+    }
+
 }
diff --git a/src/java/org/apache/fop/layoutmgr/BlockStackingLayoutManager.java b/src/java/org/apache/fop/layoutmgr/BlockStackingLayoutManager.java
index 403bd6f68..78ab6711a 100644
--- a/src/java/org/apache/fop/layoutmgr/BlockStackingLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/BlockStackingLayoutManager.java
@@ -38,7 +38,6 @@ import org.apache.fop.fo.properties.KeepProperty;
 import org.apache.fop.fo.properties.SpaceProperty;
 import org.apache.fop.layoutmgr.inline.InlineLayoutManager;
 import org.apache.fop.traits.MinOptMax;
-import org.apache.fop.util.BreakUtil;
 import org.apache.fop.util.ListUtil;
 
 /**
@@ -1036,7 +1035,7 @@ public abstract class BlockStackingLayoutManager extends AbstractLayoutManager
      * @return true if an element has been added due to a break-before.
      */
     protected boolean addKnuthElementsForBreakBefore(List returnList, LayoutContext context) {
-        int breakBefore = getBreakBefore();
+        int breakBefore = BreakOpportunityHelper.getBreakBefore(this);
         if (breakBefore == EN_PAGE
                 || breakBefore == EN_COLUMN
                 || breakBefore == EN_EVEN_PAGE
@@ -1051,27 +1050,6 @@ public abstract class BlockStackingLayoutManager extends AbstractLayoutManager
     }
 
     /**
-     * Returns the break-before value of the current formatting object.
-     * @return the break-before value (Constants.EN_*)
-     */
-    private int getBreakBefore() {
-        int breakBefore = EN_AUTO;
-        if (fobj instanceof BreakPropertySet) {
-            breakBefore = ((BreakPropertySet)fobj).getBreakBefore();
-        }
-        if (true /* uncomment to only partially merge: && breakBefore != EN_AUTO*/) {
-            LayoutManager lm = getChildLM();
-            //It is assumed this is only called when the first LM is active.
-            if (lm instanceof BlockStackingLayoutManager) {
-                BlockStackingLayoutManager bslm = (BlockStackingLayoutManager)lm;
-                breakBefore = BreakUtil.compareBreakClasses(
-                        breakBefore, bslm.getBreakBefore());
-            }
-        }
-        return breakBefore;
-    }
-
-    /**
      * Creates Knuth elements for break-after and adds them to the return list.
      * @param returnList return list to add the additional elements to
      * @param context the layout context
diff --git a/src/java/org/apache/fop/layoutmgr/BreakOpportunity.java b/src/java/org/apache/fop/layoutmgr/BreakOpportunity.java
new file mode 100644
index 000000000..668f112c9
--- /dev/null
+++ b/src/java/org/apache/fop/layoutmgr/BreakOpportunity.java
@@ -0,0 +1,36 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.layoutmgr;
+
+/**
+ * Defines methods to evaluate break opportunities at a particular location in the tree of
+ * layout managers.
+ */
+public interface BreakOpportunity {
+
+    /**
+     * Returns the highest priority break-before value on this layout manager or its
+     * relevant descendants.
+     *
+     * @return the break-before value (Constants.EN_*)
+     */
+    int getBreakBefore();
+
+}
diff --git a/src/java/org/apache/fop/layoutmgr/BreakOpportunityHelper.java b/src/java/org/apache/fop/layoutmgr/BreakOpportunityHelper.java
new file mode 100644
index 000000000..a3992567f
--- /dev/null
+++ b/src/java/org/apache/fop/layoutmgr/BreakOpportunityHelper.java
@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.layoutmgr;
+
+import org.apache.fop.fo.Constants;
+import org.apache.fop.fo.properties.BreakPropertySet;
+import org.apache.fop.util.BreakUtil;
+
+/**
+ * Helper implementations of the {@link BreakOpportunity} methods.
+ */
+public final class BreakOpportunityHelper {
+
+    private BreakOpportunityHelper() { }
+
+    /**
+     * Returns the break opportunity before the given layout manager. There is a break
+     * opportunity if the LM's FO has the break-before property set, or if there is a
+     * break opportunity before its first child LM.
+     *
+     * @return the break-before value (Constants.EN_*)
+     */
+    public static int getBreakBefore(AbstractLayoutManager layoutManager) {
+        int breakBefore = Constants.EN_AUTO;
+        if (layoutManager.getFObj() instanceof BreakPropertySet) {
+            breakBefore = ((BreakPropertySet) layoutManager.getFObj()).getBreakBefore();
+        }
+        LayoutManager childLM = layoutManager.getChildLM();
+        // It is assumed this is only called when the first LM is active.
+        if (childLM instanceof BreakOpportunity) {
+            BreakOpportunity bo = (BreakOpportunity) childLM;
+            breakBefore = BreakUtil.compareBreakClasses(breakBefore, bo.getBreakBefore());
+        }
+        return breakBefore;
+    }
+
+}
diff --git a/src/java/org/apache/fop/layoutmgr/inline/InlineLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/InlineLayoutManager.java
index 1eb91e0ab..e87b29b2d 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/InlineLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/InlineLayoutManager.java
@@ -388,6 +388,13 @@ public class InlineLayoutManager extends InlineStackingLayoutManager {
             }
             lastSequence = ListUtil.getLast(returnList);
             lastChildLM = curLM;
+            // the context used to create this childLC above was applied a LayoutContext.SUPPRESS_BREAK_BEFORE
+            // in the getNextChildElements() method of the parent BlockLayoutManger; as a consequence all
+            // line breaks in blocks nested inside the inline associated with this ILM are being supressed;
+            // here we revert that supression; we do not need to do that for the first element since that
+            // is handled by the getBreakBefore() method of the wrapping BlockStackingLayoutManager.
+            // Note: this fix seems to work but is far from being the ideal way to do this
+            childLC.setFlags(LayoutContext.SUPPRESS_BREAK_BEFORE, false);
         }
 
         if (lastSequence != null) {
diff --git a/src/java/org/apache/fop/layoutmgr/inline/InlineStackingLayoutManager.java b/src/java/org/apache/fop/layoutmgr/inline/InlineStackingLayoutManager.java
index 4a203d55e..3e9b85742 100644
--- a/src/java/org/apache/fop/layoutmgr/inline/InlineStackingLayoutManager.java
+++ b/src/java/org/apache/fop/layoutmgr/inline/InlineStackingLayoutManager.java
@@ -28,6 +28,8 @@ import org.apache.fop.area.inline.Space;
 import org.apache.fop.fo.FObj;
 import org.apache.fop.fo.properties.SpaceProperty;
 import org.apache.fop.layoutmgr.AbstractLayoutManager;
+import org.apache.fop.layoutmgr.BreakOpportunity;
+import org.apache.fop.layoutmgr.BreakOpportunityHelper;
 import org.apache.fop.layoutmgr.KnuthElement;
 import org.apache.fop.layoutmgr.LayoutContext;
 import org.apache.fop.layoutmgr.NonLeafPosition;
@@ -39,8 +41,8 @@ import org.apache.fop.traits.MinOptMax;
  * which stack children in the inline direction, such as Inline or
  * Line. It should not be instantiated directly.
  */
-public abstract class InlineStackingLayoutManager extends AbstractLayoutManager
-                                         implements InlineLevelLayoutManager {
+public abstract class InlineStackingLayoutManager extends AbstractLayoutManager implements
+        InlineLevelLayoutManager, BreakOpportunity {
 
     /**
      * Size of border and padding in BPD (ie, before and after).
@@ -385,4 +387,9 @@ public abstract class InlineStackingLayoutManager extends AbstractLayoutManager
 
         return returnList;
     }
+
+    public int getBreakBefore() {
+        return BreakOpportunityHelper.getBreakBefore(this);
+    }
+
 }