Bug 46693. Check to see if we CanContinueTextRun() while walking over the frames to FindNextText(). This revives the logic that I nuked when fixing 19051, and keeps you from trying to walk over <br> or other frames to erroneously continue a text run. r=akkana.

layout/base/public/nsIFrame.h

@@ -915,6 +915,19 @@ public:
 
   // XXX Maybe these three should be a separate interface?
 
+  /**
+   * Helper method used by block reflow to identify runs of text so
+   * that proper word-breaking can be done.
+   *
+   * @param aContinueTextRun A frame should set aContinueTextRun to
+   *    PR_TRUE if we can continue a "text run" through the frame. A
+   *    text run is text that should be treated contiguously for line
+   *    and word breaking.
+   *
+   * @return The return value is irrelevant.
+   */
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const = 0;
+
   // Justification helper method used to distribute extra space in a
   // line to leaf frames. aUsedSpace is filled in with the amount of
   // space actually used.

layout/generic/nsFirstLetterFrame.cpp

@@ -53,6 +53,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus);
 
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
+
   NS_IMETHOD SetSelected(nsIPresContext* aPresContext, nsIDOMRange *aRange,PRBool aSelected, nsSpread aSpread);
 
 //override of nsFrame method
@@ -307,6 +309,14 @@ nsFirstLetterFrame::Reflow(nsIPresContext*          aPresContext,
   return rv;
 }
 
+NS_IMETHODIMP
+nsFirstLetterFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // We can continue a text run through a first-letter frame.
+  aContinueTextRun = PR_TRUE;
+  return NS_OK;
+}
+
 void
 nsFirstLetterFrame::DrainOverflowFrames(nsIPresContext* aPresContext)
 {

layout/generic/nsFrame.cpp

@@ -1665,6 +1665,15 @@ nsFrame::DidReflow(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // By default, a frame will *not* allow a text run to be continued
+  // through it.
+  aContinueTextRun = PR_FALSE;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsFrame::Reflow(nsIPresContext*          aPresContext,
                 nsHTMLReflowMetrics&     aDesiredSize,

layout/generic/nsFrame.h

@@ -279,6 +279,7 @@ public:
                      nsReflowStatus&          aStatus);
   NS_IMETHOD  DidReflow(nsIPresContext* aPresContext,
                         nsDidReflowStatus aStatus);
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
   NS_IMETHOD AdjustFrameSize(nscoord aExtraSpace, nscoord& aUsedSpace);
   NS_IMETHOD TrimTrailingWhiteSpace(nsIPresContext* aPresContext,
                                     nsIRenderingContext& aRC,

layout/generic/nsIFrame.h

@@ -915,6 +915,19 @@ public:
 
   // XXX Maybe these three should be a separate interface?
 
+  /**
+   * Helper method used by block reflow to identify runs of text so
+   * that proper word-breaking can be done.
+   *
+   * @param aContinueTextRun A frame should set aContinueTextRun to
+   *    PR_TRUE if we can continue a "text run" through the frame. A
+   *    text run is text that should be treated contiguously for line
+   *    and word breaking.
+   *
+   * @return The return value is irrelevant.
+   */
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const = 0;
+
   // Justification helper method used to distribute extra space in a
   // line to leaf frames. aUsedSpace is filled in with the amount of
   // space actually used.

layout/generic/nsInlineFrame.cpp

@@ -328,6 +328,14 @@ nsInlineFrame::Reflow(nsIPresContext*          aPresContext,
   return rv;
 }
 
+NS_IMETHODIMP
+nsInlineFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // We can continue a text run through an inline frame
+  aContinueTextRun = PR_TRUE;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsInlineFrame::ReflowDirtyChild(nsIPresShell* aPresShell, nsIFrame* aChild)
 {

layout/generic/nsInlineFrame.h

@@ -79,6 +79,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus& aStatus);
 
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
+
   static nsIID kInlineFrameCID;
 
   // Take all of the frames away from this frame. The caller is

layout/generic/nsLineLayout.cpp

@@ -2824,6 +2824,12 @@ nsLineLayout::FindNextText(nsIPresContext* aPresContext, nsIFrame* aFrame)
       continue;
     }
 
+    // If this is a frame that'll break a word, then bail.
+    PRBool canContinue;
+    next->CanContinueTextRun(canContinue);
+    if (! canContinue)
+      break;
+
     // We know top's parent is good, but next's might not be. So let's
     // set it to be sure.
     nsIFrame* parent;

layout/generic/nsTextFrame.cpp

@@ -434,6 +434,7 @@ public:
                     nsHTMLReflowMetrics& aMetrics,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus& aStatus);
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
   NS_IMETHOD AdjustFrameSize(nscoord aExtraSpace, nscoord& aUsedSpace);
   NS_IMETHOD TrimTrailingWhiteSpace(nsIPresContext* aPresContext,
                                     nsIRenderingContext& aRC,
@@ -4364,6 +4365,14 @@ nsTextFrame::Reflow(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsTextFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // We can continue a text run through a text frame
+  aContinueTextRun = PR_TRUE;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsTextFrame::AdjustFrameSize(nscoord aExtraSpace, nscoord& aUsedSpace)
 {

layout/html/base/src/nsFirstLetterFrame.cpp

@@ -53,6 +53,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus);
 
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
+
   NS_IMETHOD SetSelected(nsIPresContext* aPresContext, nsIDOMRange *aRange,PRBool aSelected, nsSpread aSpread);
 
 //override of nsFrame method
@@ -307,6 +309,14 @@ nsFirstLetterFrame::Reflow(nsIPresContext*          aPresContext,
   return rv;
 }
 
+NS_IMETHODIMP
+nsFirstLetterFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // We can continue a text run through a first-letter frame.
+  aContinueTextRun = PR_TRUE;
+  return NS_OK;
+}
+
 void
 nsFirstLetterFrame::DrainOverflowFrames(nsIPresContext* aPresContext)
 {

layout/html/base/src/nsFrame.cpp

@@ -1665,6 +1665,15 @@ nsFrame::DidReflow(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // By default, a frame will *not* allow a text run to be continued
+  // through it.
+  aContinueTextRun = PR_FALSE;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsFrame::Reflow(nsIPresContext*          aPresContext,
                 nsHTMLReflowMetrics&     aDesiredSize,

layout/html/base/src/nsFrame.h

@@ -279,6 +279,7 @@ public:
                      nsReflowStatus&          aStatus);
   NS_IMETHOD  DidReflow(nsIPresContext* aPresContext,
                         nsDidReflowStatus aStatus);
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
   NS_IMETHOD AdjustFrameSize(nscoord aExtraSpace, nscoord& aUsedSpace);
   NS_IMETHOD TrimTrailingWhiteSpace(nsIPresContext* aPresContext,
                                     nsIRenderingContext& aRC,

layout/html/base/src/nsInlineFrame.cpp

@@ -328,6 +328,14 @@ nsInlineFrame::Reflow(nsIPresContext*          aPresContext,
   return rv;
 }
 
+NS_IMETHODIMP
+nsInlineFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // We can continue a text run through an inline frame
+  aContinueTextRun = PR_TRUE;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsInlineFrame::ReflowDirtyChild(nsIPresShell* aPresShell, nsIFrame* aChild)
 {

layout/html/base/src/nsInlineFrame.h

@@ -79,6 +79,8 @@ public:
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus& aStatus);
 
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
+
   static nsIID kInlineFrameCID;
 
   // Take all of the frames away from this frame. The caller is

layout/html/base/src/nsLineLayout.cpp

@@ -2824,6 +2824,12 @@ nsLineLayout::FindNextText(nsIPresContext* aPresContext, nsIFrame* aFrame)
       continue;
     }
 
+    // If this is a frame that'll break a word, then bail.
+    PRBool canContinue;
+    next->CanContinueTextRun(canContinue);
+    if (! canContinue)
+      break;
+
     // We know top's parent is good, but next's might not be. So let's
     // set it to be sure.
     nsIFrame* parent;

layout/html/base/src/nsTextFrame.cpp

@@ -434,6 +434,7 @@ public:
                     nsHTMLReflowMetrics& aMetrics,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus& aStatus);
+  NS_IMETHOD CanContinueTextRun(PRBool& aContinueTextRun) const;
   NS_IMETHOD AdjustFrameSize(nscoord aExtraSpace, nscoord& aUsedSpace);
   NS_IMETHOD TrimTrailingWhiteSpace(nsIPresContext* aPresContext,
                                     nsIRenderingContext& aRC,
@@ -4364,6 +4365,14 @@ nsTextFrame::Reflow(nsIPresContext* aPresContext,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsTextFrame::CanContinueTextRun(PRBool& aContinueTextRun) const
+{
+  // We can continue a text run through a text frame
+  aContinueTextRun = PR_TRUE;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsTextFrame::AdjustFrameSize(nscoord aExtraSpace, nscoord& aUsedSpace)
 {