From cb4f2aea5c0623db2323d129b2dcd8138bb759ea Mon Sep 17 00:00:00 2001
From: "dbaron%fas.harvard.edu" <dbaron%fas.harvard.edu>
Date: Sat, 3 Nov 2001 05:18:39 +0000
Subject: [PATCH] Fix FMR/FMW caused by translating the space manager right
 after deleting it.  r=jag  sr=waterson  b=108017

---
 layout/generic/nsBlockFrame.cpp             |  1 +
 layout/generic/nsBlockReflowState.cpp       | 21 ++++++++++++++++++---
 layout/html/base/src/nsBlockFrame.cpp       |  1 +
 layout/html/base/src/nsBlockReflowState.cpp | 21 ++++++++++++++++++---
 4 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 6b63a9e6df02..80f7f6b0cf68 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -884,6 +884,7 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
     if (!transferredSpaceManager)
 #endif
       delete spaceManager;
+    state.mSpaceManager = nsnull;
   }
 
 #ifdef NOISY_SPACEMANAGER
diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index b19b83c35a99..b006b45e616c 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -176,9 +176,12 @@ nsBlockReflowState::nsBlockReflowState(const nsHTMLReflowState& aReflowState,
 
 nsBlockReflowState::~nsBlockReflowState()
 {
-  // Restore the coordinate system
-  const nsMargin& borderPadding = BorderPadding();
-  mSpaceManager->Translate(-borderPadding.left, -borderPadding.top);
+  // Restore the coordinate system, unless the space manager is null,
+  // which means it was just destroyed.
+  if (mSpaceManager) {
+    const nsMargin& borderPadding = BorderPadding();
+    mSpaceManager->Translate(-borderPadding.left, -borderPadding.top);
+  }
 }
 
 nsLineBox*
@@ -471,6 +474,18 @@ nsBlockReflowState::ReconstructMarginAbove(nsLineList::iterator aLine)
   }
 }
 
+/**
+ * Everything done in this function is done O(N) times for each pass of
+ * reflow so it is O(N*M) where M is the number of incremental reflow
+ * passes.  That's bad.  Don't do stuff here.
+ *
+ * When this function is called, |aLine| has just been slid by |aDeltaY|
+ * and the purpose of RecoverStateFrom is to ensure that the
+ * nsBlockReflowState is in the same state that it would have been in
+ * had the line just been reflowed.
+ *
+ * Most of the state recovery that we have to do involves floaters.
+ */
 void
 nsBlockReflowState::RecoverStateFrom(nsLineList::iterator aLine,
                                      nscoord aDeltaY)
diff --git a/layout/html/base/src/nsBlockFrame.cpp b/layout/html/base/src/nsBlockFrame.cpp
index 6b63a9e6df02..80f7f6b0cf68 100644
--- a/layout/html/base/src/nsBlockFrame.cpp
+++ b/layout/html/base/src/nsBlockFrame.cpp
@@ -884,6 +884,7 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
     if (!transferredSpaceManager)
 #endif
       delete spaceManager;
+    state.mSpaceManager = nsnull;
   }
 
 #ifdef NOISY_SPACEMANAGER
diff --git a/layout/html/base/src/nsBlockReflowState.cpp b/layout/html/base/src/nsBlockReflowState.cpp
index b19b83c35a99..b006b45e616c 100644
--- a/layout/html/base/src/nsBlockReflowState.cpp
+++ b/layout/html/base/src/nsBlockReflowState.cpp
@@ -176,9 +176,12 @@ nsBlockReflowState::nsBlockReflowState(const nsHTMLReflowState& aReflowState,
 
 nsBlockReflowState::~nsBlockReflowState()
 {
-  // Restore the coordinate system
-  const nsMargin& borderPadding = BorderPadding();
-  mSpaceManager->Translate(-borderPadding.left, -borderPadding.top);
+  // Restore the coordinate system, unless the space manager is null,
+  // which means it was just destroyed.
+  if (mSpaceManager) {
+    const nsMargin& borderPadding = BorderPadding();
+    mSpaceManager->Translate(-borderPadding.left, -borderPadding.top);
+  }
 }
 
 nsLineBox*
@@ -471,6 +474,18 @@ nsBlockReflowState::ReconstructMarginAbove(nsLineList::iterator aLine)
   }
 }
 
+/**
+ * Everything done in this function is done O(N) times for each pass of
+ * reflow so it is O(N*M) where M is the number of incremental reflow
+ * passes.  That's bad.  Don't do stuff here.
+ *
+ * When this function is called, |aLine| has just been slid by |aDeltaY|
+ * and the purpose of RecoverStateFrom is to ensure that the
+ * nsBlockReflowState is in the same state that it would have been in
+ * had the line just been reflowed.
+ *
+ * Most of the state recovery that we have to do involves floaters.
+ */
 void
 nsBlockReflowState::RecoverStateFrom(nsLineList::iterator aLine,
                                      nscoord aDeltaY)