Bug 1332353 - Make it clearer when a stylesheet is really owned by its mDocument

Tag #1375

10 files changed, 69 insertions, 24 deletions

diff --git a/layout/style/CSSStyleSheet.cpp b/layout/style/CSSStyleSheet.cpp
index 71ca6e3f2c..43d47100d1 100644
--- a/layout/style/CSSStyleSheet.cpp
+++ b/layout/style/CSSStyleSheet.cpp
@@ -694,7 +694,7 @@ nsMediaList::GetMediaText(nsAString& aMediaText)
 // nsCOMPtr<nsIDocument>
 #define BEGIN_MEDIA_CHANGE(sheet, doc)                         \
   if (sheet) {                                                 \
-    doc = sheet->GetOwningDocument();                          \
+    doc = sheet->GetAssociatedDocument();                      \
   }                                                            \
   mozAutoDocUpdate updateBatch(doc, UPDATE_STYLE, true);       \
   if (sheet) {                                                 \
@@ -864,7 +864,8 @@ struct ChildSheetListBuilder {
 
   void SetParentLinks(CSSStyleSheet* aSheet) {
     aSheet->mParent = parent;
-    aSheet->SetOwningDocument(parent->mDocument);
+    aSheet->SetAssociatedDocument(parent->mDocument,
+                                  parent->mDocumentAssociationMode);
   }
 
   static void ReparentChildList(CSSStyleSheet* aPrimarySheet,
@@ -872,7 +873,8 @@ struct ChildSheetListBuilder {
   {
     for (CSSStyleSheet *child = aFirstChild; child; child = child->mNext) {
       child->mParent = aPrimarySheet;
-      child->SetOwningDocument(aPrimarySheet->mDocument);
+      child->SetAssociatedDocument(aPrimarySheet->mDocument,
+                                   aPrimarySheet->mDocumentAssociationMode);
     }
   }
 };
@@ -1359,16 +1361,22 @@ CSSStyleSheet::GetParentSheet() const
 }
 
 void
-CSSStyleSheet::SetOwningDocument(nsIDocument* aDocument)
-{ // not ref counted
+CSSStyleSheet::SetAssociatedDocument(nsIDocument* aDocument,
+                                     DocumentAssociationMode aAssociationMode)
+{
+  MOZ_ASSERT_IF(!aDocument, aAssociationMode == NotOwnedByDocument);
+
+  // not ref counted
   mDocument = aDocument;
+  mDocumentAssociationMode = aAssociationMode;
+
   // Now set the same document on all our child sheets....
   // XXXbz this is a little bogus; see the XXX comment where we
   // declare mFirstChild.
   for (CSSStyleSheet* child = mInner->mFirstChild;
        child; child = child->mNext) {
     if (child->mParent == this) {
-      child->SetOwningDocument(aDocument);
+      child->SetAssociatedDocument(aDocument, aAssociationMode);
     }
   }
 }
diff --git a/layout/style/CSSStyleSheet.h b/layout/style/CSSStyleSheet.h
index 74e12291ef..89189d7816 100644
--- a/layout/style/CSSStyleSheet.h
+++ b/layout/style/CSSStyleSheet.h
@@ -129,7 +129,8 @@ public:
 
   // style sheet owner info
   CSSStyleSheet* GetParentSheet() const;  // may be null
-  void SetOwningDocument(nsIDocument* aDocument);
+  void SetAssociatedDocument(nsIDocument* aDocument,
+                             DocumentAssociationMode aAssociationMode);
 
   // Find the ID of the owner inner window.
   uint64_t FindOwningWindowInnerID() const;
diff --git a/layout/style/Loader.cpp b/layout/style/Loader.cpp
index 0ce337e29f..d4edfe81d0 100644
--- a/layout/style/Loader.cpp
+++ b/layout/style/Loader.cpp
@@ -2209,9 +2209,9 @@ Loader::LoadChildSheet(StyleSheet* aParentSheet,
 
   nsCOMPtr<nsINode> owningNode;
 
-  // check for an owning document: if none, don't bother walking up the parent
-  // sheets
-  if (aParentSheet->GetOwningDocument()) {
+  // check for an associated document: if none, don't bother walking up the
+  // parent sheets
+  if (aParentSheet->GetAssociatedDocument()) {
     StyleSheet* topSheet = aParentSheet;
     while (StyleSheet* parent = topSheet->GetParentSheet()) {
       topSheet = parent;
diff --git a/layout/style/ServoStyleSheet.cpp b/layout/style/ServoStyleSheet.cpp
index cfeae20d2f..5f2a925b59 100644
--- a/layout/style/ServoStyleSheet.cpp
+++ b/layout/style/ServoStyleSheet.cpp
@@ -30,19 +30,23 @@ ServoStyleSheet::HasRules() const
 }
 
 void
-ServoStyleSheet::SetOwningDocument(nsIDocument* aDocument)
+ServoStyleSheet::SetAssociatedDocument(nsIDocument* aDocument,
+                                       DocumentAssociationMode aAssociationMode)
 {
+  MOZ_ASSERT_IF(!aDocument, aAssociationMode == NotOwnedByDocument);
+
   // XXXheycam: Traverse to child ServoStyleSheets to set this, like
-  // CSSStyleSheet::SetOwningDocument does.
+  // CSSStyleSheet::SetAssociatedDocument does.
 
   mDocument = aDocument;
+  mDocumentAssociationMode = aAssociationMode;
 }
 
 ServoStyleSheet*
 ServoStyleSheet::GetParentSheet() const
 {
   // XXXheycam: When we implement support for child sheets, we'll have
-  // to fix SetOwningDocument to propagate the owning document down
+  // to fix SetAssociatedDocument to propagate the associated document down
   // to the children.
   MOZ_CRASH("stylo: not implemented");
 }
diff --git a/layout/style/ServoStyleSheet.h b/layout/style/ServoStyleSheet.h
index 079f196eb9..c54c15e7d5 100644
--- a/layout/style/ServoStyleSheet.h
+++ b/layout/style/ServoStyleSheet.h
@@ -29,7 +29,8 @@ public:
 
   bool HasRules() const;
 
-  void SetOwningDocument(nsIDocument* aDocument);
+  void SetAssociatedDocument(nsIDocument* aDocument,
+                             DocumentAssociationMode aAssociationMode);
 
   ServoStyleSheet* GetParentSheet() const;
   void AppendStyleSheet(ServoStyleSheet* aSheet);
diff --git a/layout/style/StyleRule.cpp b/layout/style/StyleRule.cpp
index 598cb7c74e..622f498ddd 100644
--- a/layout/style/StyleRule.cpp
+++ b/layout/style/StyleRule.cpp
@@ -1209,13 +1209,13 @@ DOMCSSDeclarationImpl::SetCSSDeclaration(DeclarationBlock* aDecl)
   NS_PRECONDITION(mRule,
          "can only be called when |GetCSSDeclaration| returned a declaration");
 
-  nsCOMPtr<nsIDocument> owningDoc;
+  nsCOMPtr<nsIDocument> doc;
   RefPtr<CSSStyleSheet> sheet = mRule->GetStyleSheet();
   if (sheet) {
-    owningDoc = sheet->GetOwningDocument();
+    doc = sheet->GetAssociatedDocument();
   }
 
-  mozAutoDocUpdate updateBatch(owningDoc, UPDATE_STYLE, true);
+  mozAutoDocUpdate updateBatch(doc, UPDATE_STYLE, true);
 
   mRule->SetDeclaration(aDecl->AsGecko());
 
@@ -1223,8 +1223,8 @@ DOMCSSDeclarationImpl::SetCSSDeclaration(DeclarationBlock* aDecl)
     sheet->DidDirty();
   }
 
-  if (owningDoc) {
-    owningDoc->StyleRuleChanged(sheet, mRule);
+  if (doc) {
+    doc->StyleRuleChanged(sheet, mRule);
   }
   return NS_OK;
 }
diff --git a/layout/style/StyleSheet.cpp b/layout/style/StyleSheet.cpp
index fa4beeb365..f125cf97e0 100644
--- a/layout/style/StyleSheet.cpp
+++ b/layout/style/StyleSheet.cpp
@@ -24,6 +24,7 @@ StyleSheet::StyleSheet(StyleBackendType aType, css::SheetParsingMode aParsingMod
   , mParsingMode(aParsingMode)
   , mType(aType)
   , mDisabled(false)
+  , mDocumentAssociationMode(NotOwnedByDocument)
 {
 }
 
@@ -36,6 +37,9 @@ StyleSheet::StyleSheet(const StyleSheet& aCopy,
   , mParsingMode(aCopy.mParsingMode)
   , mType(aCopy.mType)
   , mDisabled(aCopy.mDisabled)
+    // We only use this constructor during cloning.  It's the cloner's
+    // responsibility to notify us if we end up being owned by a document.
+  , mDocumentAssociationMode(NotOwnedByDocument)
 {
 }
 
diff --git a/layout/style/StyleSheet.h b/layout/style/StyleSheet.h
index 863f6d22fa..7a1a71466a 100644
--- a/layout/style/StyleSheet.h
+++ b/layout/style/StyleSheet.h
@@ -95,8 +95,22 @@ public:
   inline bool HasRules() const;
 
   // style sheet owner info
-  nsIDocument* GetOwningDocument() const { return mDocument; }
-  inline void SetOwningDocument(nsIDocument* aDocument);
+  enum DocumentAssociationMode {
+    // OwnedByDocument means mDocument owns us (possibly via a chain of other
+    // stylesheets).
+    OwnedByDocument,
+    // NotOwnedByDocument means we're owned by something that might have a
+    // different lifetime than mDocument.
+    NotOwnedByDocument
+  };
+  nsIDocument* GetAssociatedDocument() const { return mDocument; }
+  bool IsOwnedByDocument() const {
+    return mDocumentAssociationMode == OwnedByDocument;
+  }
+  // aDocument must not be null.
+  inline void SetAssociatedDocument(nsIDocument* aDocument,
+                                    DocumentAssociationMode aMode);
+  inline void ClearAssociatedDocument();
   nsINode* GetOwnerNode() const { return mOwningNode; }
   inline StyleSheet* GetParentSheet() const;
 
@@ -206,6 +220,11 @@ protected:
 
   const StyleBackendType mType;
   bool                  mDisabled;
+
+  // mDocumentAssociationMode determines whether mDocument directly owns us (in
+  // the sense that if it's known-live then we're known-live).  Always
+  // NotOwnedByDocument when mDocument is null.
+  DocumentAssociationMode mDocumentAssociationMode;
 };
 
 } // namespace mozilla
diff --git a/layout/style/StyleSheetInlines.h b/layout/style/StyleSheetInlines.h
index d03a3741b7..c0b8495f87 100644
--- a/layout/style/StyleSheetInlines.h
+++ b/layout/style/StyleSheetInlines.h
@@ -83,9 +83,17 @@ StyleSheet::HasRules() const
 }
 
 void
-StyleSheet::SetOwningDocument(nsIDocument* aDocument)
+StyleSheet::SetAssociatedDocument(nsIDocument* aDocument,
+                                  DocumentAssociationMode aAssociationMode)
 {
-  MOZ_STYLO_FORWARD(SetOwningDocument, (aDocument))
+  MOZ_ASSERT(aDocument);
+  MOZ_STYLO_FORWARD(SetAssociatedDocument, (aDocument, aAssociationMode))
+}
+
+void
+StyleSheet::ClearAssociatedDocument()
+{
+  MOZ_STYLO_FORWARD(SetAssociatedDocument, (nullptr, NotOwnedByDocument));
 }
 
 StyleSheet*
diff --git a/layout/style/nsDOMCSSDeclaration.cpp b/layout/style/nsDOMCSSDeclaration.cpp
index bd6c6069d0..51ce8c335c 100644
--- a/layout/style/nsDOMCSSDeclaration.cpp
+++ b/layout/style/nsDOMCSSDeclaration.cpp
@@ -267,7 +267,7 @@ nsDOMCSSDeclaration::GetCSSParsingEnvironmentForRule(css::Rule* aRule,
     return;
   }
 
-  nsIDocument* document = sheet->GetOwningDocument();
+  nsIDocument* document = sheet->GetAssociatedDocument();
   aCSSParseEnv.mSheetURI = sheet->GetSheetURI();
   aCSSParseEnv.mBaseURI = sheet->GetBaseURI();
   aCSSParseEnv.mPrincipal = sheet->Principal();