FOP-3181 Prevent page duplication when ipd changesHEADmain

6 files changed, 60 insertions, 2 deletions

diff --git a/fop-core/src/main/java/org/apache/fop/apps/FOUserAgent.java b/fop-core/src/main/java/org/apache/fop/apps/FOUserAgent.java
index 4c6b2c100..32d11475f 100644
--- a/fop-core/src/main/java/org/apache/fop/apps/FOUserAgent.java
+++ b/fop-core/src/main/java/org/apache/fop/apps/FOUserAgent.java
@@ -540,6 +540,16 @@ public class FOUserAgent {
     }
 
     /**
+     * Are invalid positions to be allowed when breaking text?
+     *
+     * @return if invalid break positions are to be allowed
+     * @see FopFactory#isLegacyInvalidBreakPosition()
+     */
+    public boolean isLegacyInvalidBreakPosition() {
+        return factory.isLegacyInvalidBreakPosition();
+    }
+
+    /**
      * @return true if the indent inheritance should be broken when crossing reference area
      *         boundaries (for more info, see the javadoc for the relative member variable)
      * @see FopFactory#isBreakIndentInheritanceOnReferenceAreaBoundary()
diff --git a/fop-core/src/main/java/org/apache/fop/apps/FopConfParser.java b/fop-core/src/main/java/org/apache/fop/apps/FopConfParser.java
index abc3a4edb..c610f766a 100644
--- a/fop-core/src/main/java/org/apache/fop/apps/FopConfParser.java
+++ b/fop-core/src/main/java/org/apache/fop/apps/FopConfParser.java
@@ -63,6 +63,7 @@ public class FopConfParser {
     private static final String LEGACY_SKIP_PAGE_POSITION_ONLY = "legacy-skip-page-position-only";
     private static final String LEGACY_LAST_PAGE_CHANGE_IPD = "legacy-last-page-change-ipd";
     private static final String LEGACY_FO_WRAPPER = "legacy-fo-wrapper";
+    private static final String LEGACY_INVALID_BREAK_POSITION = "legacy-invalid-break-position";
 
     private static final Log LOG = LogFactory.getLog(FopConfParser.class);
     private static final String ACCESSIBILITY = "accessibility";
@@ -330,6 +331,14 @@ public class FopConfParser {
                 LogUtil.handleException(LOG, e, false);
             }
         }
+        if (cfg.getChild(LEGACY_INVALID_BREAK_POSITION, false) != null) {
+            try {
+                fopFactoryBuilder.setLegacyInvalidBreakPosition(
+                        cfg.getChild(LEGACY_INVALID_BREAK_POSITION).getValueAsBoolean());
+            } catch (ConfigurationException e) {
+                LogUtil.handleException(LOG, e, strict);
+            }
+        }
 
         // configure font manager
         new FontManagerConfigurator(cfg, baseURI, fopFactoryBuilder.getBaseURI(), resourceResolver)
diff --git a/fop-core/src/main/java/org/apache/fop/apps/FopFactory.java b/fop-core/src/main/java/org/apache/fop/apps/FopFactory.java
index 46ec3ceb1..7befef58d 100644
--- a/fop-core/src/main/java/org/apache/fop/apps/FopFactory.java
+++ b/fop-core/src/main/java/org/apache/fop/apps/FopFactory.java
@@ -256,6 +256,10 @@ public final class FopFactory implements ImageContext {
         return config.isLegacyFoWrapper();
     }
 
+    public boolean isLegacyInvalidBreakPosition() {
+        return config.isLegacyInvalidBreakPosition();
+    }
+
     /**
      * Returns a new {@link Fop} instance. FOP will be configured with a default user agent
      * instance. Use this factory method if your output type requires an output stream.
diff --git a/fop-core/src/main/java/org/apache/fop/apps/FopFactoryBuilder.java b/fop-core/src/main/java/org/apache/fop/apps/FopFactoryBuilder.java
index e89021412..243bc8570 100644
--- a/fop-core/src/main/java/org/apache/fop/apps/FopFactoryBuilder.java
+++ b/fop-core/src/main/java/org/apache/fop/apps/FopFactoryBuilder.java
@@ -375,6 +375,11 @@ public final class FopFactoryBuilder {
         return this;
     }
 
+    public FopFactoryBuilder setLegacyInvalidBreakPosition(boolean value) {
+        fopFactoryConfigBuilder.setLegacyInvalidBreakPosition(value);
+        return this;
+    }
+
     public static class FopFactoryConfigImpl implements FopFactoryConfig {
 
         private final EnvironmentProfile enviro;
@@ -429,6 +434,8 @@ public final class FopFactoryBuilder {
 
         private boolean legacyFoWrapper;
 
+        private boolean legacyInvalidBreakPosition = FopFactoryConfig.DEFAULT_LEGACY_INVALID_BREAK_POSITION;
+
         private static final class ImageContextImpl implements ImageContext {
 
             private final FopFactoryConfig config;
@@ -573,6 +580,10 @@ public final class FopFactoryBuilder {
             return legacyFoWrapper;
         }
 
+        public boolean isLegacyInvalidBreakPosition() {
+            return legacyInvalidBreakPosition;
+        }
+
         public Map<String, String> getHyphenationPatternNames() {
             return hyphPatNames;
         }
@@ -600,6 +611,8 @@ public final class FopFactoryBuilder {
 
         void setStrictUserConfigValidation(boolean validateStrictly);
 
+        void setLegacyInvalidBreakPosition(boolean invalidBreakPosition);
+
         void setBreakIndentInheritanceOnReferenceAreaBoundary(boolean value);
 
         void setSourceResolution(float dpi);
@@ -677,6 +690,10 @@ public final class FopFactoryBuilder {
             throwIllegalStateException();
         }
 
+        public void setLegacyInvalidBreakPosition(boolean ignoreInvalidBreakPosition) {
+            throwIllegalStateException();
+        }
+
         public void setBreakIndentInheritanceOnReferenceAreaBoundary(
                 boolean value) {
             throwIllegalStateException();
@@ -788,8 +805,7 @@ public final class FopFactoryBuilder {
             config.hasStrictUserValidation = validateStrictly;
         }
 
-        public void setBreakIndentInheritanceOnReferenceAreaBoundary(
-                boolean value) {
+        public void setBreakIndentInheritanceOnReferenceAreaBoundary(boolean value) {
             config.breakIndentInheritanceOnReferenceBoundary = value;
         }
 
@@ -857,6 +873,10 @@ public final class FopFactoryBuilder {
         public void setLegacyFoWrapper(boolean b) {
             config.legacyFoWrapper = b;
         }
+
+        public void setLegacyInvalidBreakPosition(boolean legacyInvalidBreakPosition) {
+            config.legacyInvalidBreakPosition = legacyInvalidBreakPosition;
+        }
     }
 
 }
diff --git a/fop-core/src/main/java/org/apache/fop/apps/FopFactoryConfig.java b/fop-core/src/main/java/org/apache/fop/apps/FopFactoryConfig.java
index 190a6f556..6f62f17e3 100644
--- a/fop-core/src/main/java/org/apache/fop/apps/FopFactoryConfig.java
+++ b/fop-core/src/main/java/org/apache/fop/apps/FopFactoryConfig.java
@@ -40,6 +40,11 @@ import org.apache.fop.layoutmgr.LayoutManagerMaker;
 // part of the API. Why would a user care how the internal objects are passed around? They shouldn't.
 public interface FopFactoryConfig {
 
+    /**
+     * Defines if FOP should allow breaks at positions deemed invalid
+     */
+    boolean DEFAULT_LEGACY_INVALID_BREAK_POSITION = false;
+
     /** Defines if FOP should use an alternative rule to determine text indents */
     boolean DEFAULT_BREAK_INDENT_INHERITANCE = false;
 
@@ -178,6 +183,8 @@ public interface FopFactoryConfig {
 
     boolean isLegacyFoWrapper();
 
+    boolean isLegacyInvalidBreakPosition();
+
     /** @return the hyphenation pattern names */
     Map<String, String> getHyphenationPatternNames();
 
diff --git a/fop-core/src/main/java/org/apache/fop/layoutmgr/RestartAtLM.java b/fop-core/src/main/java/org/apache/fop/layoutmgr/RestartAtLM.java
index 4a0fcd885..647c9968f 100644
--- a/fop-core/src/main/java/org/apache/fop/layoutmgr/RestartAtLM.java
+++ b/fop-core/src/main/java/org/apache/fop/layoutmgr/RestartAtLM.java
@@ -100,10 +100,18 @@ class RestartAtLM {
                     position = position.getPosition();
                 }
                 if (position.getPosition() == null) {
+                    if (!breaker.getPageProvider().foUserAgent.isLegacyInvalidBreakPosition()) {
+                        breaker.firstElementsForRestart = new LinkedList<>();
+                        breaker.positionAtBreak = new LeafPosition(surroundingLM, positionIndex + 1);
+
+                        return surroundingLM;
+                    }
+
                     if (!position.getLM().getFObj().isForceKeepTogether()) {
                         position.getLM().getFObj().setForceKeepTogether(true);
                         invalidPosition = true;
                     }
+
                     return null;
                 }
                 restartAtLM = position.getPosition().getLM();