Bug 1620289 - Part 1 Clone Selection Ranges For Printing r=jwatt

- Clones selection ranges to the static document for printing
- Static docs can remove selections without referring to original doc

Differential Revision: https://phabricator.services.mozilla.com/D71110

layout/printing/nsPrintJob.cpp

@@ -142,7 +142,7 @@ static const char* gPrintRangeStr[] = {
 // This processes the selection on aOrigDoc and creates an inverted selection on
 // aDoc, which it then deletes. If the start or end of the inverted selection
 // ranges occur in text nodes then an ellipsis is added.
-static nsresult DeleteUnselectedNodes(Document* aOrigDoc, Document* aDoc);
+static nsresult DeleteNonSelectedNodes(Document& aDoc);
 
 #ifdef EXTENDED_DEBUG_PRINTING
 // Forward Declarations
@@ -2053,8 +2053,7 @@ nsresult nsPrintJob::ReflowPrintObject(const UniquePtr<nsPrintObject>& aPO) {
   int16_t printRangeType = nsIPrintSettings::kRangeAllPages;
   printData->mPrintSettings->GetPrintRange(&printRangeType);
   if (printRangeType == nsIPrintSettings::kRangeSelection) {
-    DeleteUnselectedNodes(aPO->mDocument->GetOriginalDocument(),
-                          aPO->mDocument);
+    DeleteNonSelectedNodes(*aPO->mDocument);
   }
 
   bool doReturn = false;
@@ -2202,61 +2201,39 @@ bool nsPrintJob::PrintDocContent(const UniquePtr<nsPrintObject>& aPO,
   return false;
 }
 
-static nsINode* GetCorrespondingNodeInDocument(const nsINode* aNode,
-                                               Document* aDoc) {
-  MOZ_ASSERT(aNode);
-  MOZ_ASSERT(aDoc);
-
-  // Selections in anonymous subtrees aren't supported.
-  if (aNode->IsInAnonymousSubtree()) {
-    return nullptr;
-  }
-
-  nsTArray<int32_t> indexArray;
-  const nsINode* child = aNode;
-  while (const nsINode* parent = child->GetParentNode()) {
-    int32_t index = parent->ComputeIndexOf(child);
-    MOZ_ASSERT(index >= 0);
-    indexArray.AppendElement(index);
-    child = parent;
-  }
-  MOZ_ASSERT(child->IsDocument());
-
-  nsINode* correspondingNode = aDoc;
-  for (int32_t i = indexArray.Length() - 1; i >= 0; --i) {
-    correspondingNode = correspondingNode->GetChildAt_Deprecated(indexArray[i]);
-    NS_ENSURE_TRUE(correspondingNode, nullptr);
-  }
-
-  return correspondingNode;
-}
-
 static NS_NAMED_LITERAL_STRING(kEllipsis, u"\x2026");
 
-MOZ_CAN_RUN_SCRIPT_BOUNDARY static nsresult DeleteUnselectedNodes(
-    Document* aOrigDoc, Document* aDoc) {
-  PresShell* origPresShell = aOrigDoc->GetPresShell();
-  PresShell* presShell = aDoc->GetPresShell();
-  NS_ENSURE_STATE(origPresShell && presShell);
+/**
+ * Builds the complement set of ranges and adds those to the selection.
+ * Deletes all of the nodes contained in the complement set of ranges
+ * leaving behind only nodes that were originally selected.
+ * Adds ellipses to a selected node's text if text is truncated by a range.
+ * This is used to implement the "Print Selection Only" user interface option.
+ */
+MOZ_CAN_RUN_SCRIPT_BOUNDARY static nsresult DeleteNonSelectedNodes(
+    Document& aDoc) {
+  MOZ_ASSERT(aDoc.IsStaticDocument());
+  const auto* printRanges = static_cast<nsTArray<RefPtr<nsRange>>*>(
+      aDoc.GetProperty(nsGkAtoms::printselectionranges));
+  if (!printRanges) {
+    return NS_OK;
+  }
 
-  RefPtr<Selection> origSelection =
-      origPresShell->GetCurrentSelection(SelectionType::eNormal);
+  PresShell* presShell = aDoc.GetPresShell();
+  NS_ENSURE_STATE(presShell);
   RefPtr<Selection> selection =
       presShell->GetCurrentSelection(SelectionType::eNormal);
-  NS_ENSURE_STATE(origSelection && selection);
+  NS_ENSURE_STATE(selection);
 
-  nsINode* bodyNode = aDoc->GetBodyElement();
+  MOZ_ASSERT(!selection->RangeCount());
+  nsINode* bodyNode = aDoc.GetBodyElement();
   nsINode* startNode = bodyNode;
   uint32_t startOffset = 0;
   uint32_t ellipsisOffset = 0;
 
-  int32_t rangeCount = origSelection->RangeCount();
-  for (int32_t i = 0; i < rangeCount; ++i) {
-    nsRange* origRange = origSelection->GetRangeAt(i);
-
+  for (nsRange* origRange : *printRanges) {
     // New end is start of original range.
-    nsINode* endNode =
-        GetCorrespondingNodeInDocument(origRange->GetStartContainer(), aDoc);
+    nsINode* endNode = origRange->GetStartContainer();
 
     // If we're no longer in the same text node reset the ellipsis offset.
     if (endNode != startNode) {
@@ -2267,13 +2244,12 @@ MOZ_CAN_RUN_SCRIPT_BOUNDARY static nsresult DeleteUnselectedNodes(
     // Create the range that we want to remove. Note that if startNode or
     // endNode are null nsRange::Create() will fail and we won't remove
     // that section.
-    RefPtr<nsRange> range = nsRange::Create(startNode, startOffset, endNode,
-                                            endOffset, IgnoreErrors());
+    RefPtr<nsRange> unselectedRange = nsRange::Create(
+        startNode, startOffset, endNode, endOffset, IgnoreErrors());
 
-    if (range && !range->Collapsed()) {
-      selection->AddRangeAndSelectFramesAndNotifyListeners(*range,
+    if (unselectedRange && !unselectedRange->Collapsed()) {
+      selection->AddRangeAndSelectFramesAndNotifyListeners(*unselectedRange,
                                                            IgnoreErrors());
-
       // Unless we've already added an ellipsis at the start, if we ended mid
       // text node then add ellipsis.
       Text* text = endNode->GetAsText();
@@ -2284,8 +2260,7 @@ MOZ_CAN_RUN_SCRIPT_BOUNDARY static nsresult DeleteUnselectedNodes(
     }
 
     // Next new start is end of original range.
-    startNode =
-        GetCorrespondingNodeInDocument(origRange->GetEndContainer(), aDoc);
+    startNode = origRange->GetEndContainer();
 
     // If we're no longer in the same text node reset the ellipsis offset.
     if (startNode != endNode) {
@@ -2310,7 +2285,6 @@ MOZ_CAN_RUN_SCRIPT_BOUNDARY static nsresult DeleteUnselectedNodes(
     selection->AddRangeAndSelectFramesAndNotifyListeners(*lastRange,
                                                          IgnoreErrors());
   }
-
   selection->DeleteFromDocument(IgnoreErrors());
   return NS_OK;
 }

layout/printing/nsPrintObject.cpp

@@ -52,11 +52,115 @@ nsPrintObject::~nsPrintObject() {
     nsDocShell::Cast(mDocShell)->Destroy();
     bc->Detach();
   }
+  if (mDocument) {
+    mDocument->RemoveProperty(nsGkAtoms::printselectionranges);
+  }
   mDocShell = nullptr;
   mTreeOwner = nullptr;  // mTreeOwner must be released after mDocShell;
 }
 
 //------------------------------------------------------------------
+
+/**
+ * Retrieves the node in a static-clone document that corresponds to aOrigNOde,
+ * which is a node in the original document from which aStaticClone was cloned.
+ */
+static nsINode* GetCorrespondingNodeInDocument(const nsINode* aOrigNode,
+                                               Document& aStaticClone) {
+  MOZ_ASSERT(aOrigNode);
+
+  // Selections in anonymous subtrees aren't supported.
+  if (aOrigNode->IsInAnonymousSubtree() || aOrigNode->IsInShadowTree()) {
+    return nullptr;
+  }
+
+  nsTArray<int32_t> indexArray;
+  const nsINode* child = aOrigNode;
+  while (const nsINode* parent = child->GetParentNode()) {
+    int32_t index = parent->ComputeIndexOf(child);
+    MOZ_ASSERT(index >= 0);
+    indexArray.AppendElement(index);
+    child = parent;
+  }
+  MOZ_ASSERT(child->IsDocument());
+
+  nsINode* correspondingNode = &aStaticClone;
+  for (int32_t i : Reversed(indexArray)) {
+    correspondingNode = correspondingNode->GetChildAt_Deprecated(i);
+    NS_ENSURE_TRUE(correspondingNode, nullptr);
+  }
+
+  return correspondingNode;
+}
+
+/**
+ * Caches the selection ranges from the source document onto the static clone in
+ * case the "Print Selection Only" functionality is invoked.
+ *
+ * Note that we cannot use the selection obtained from
+ * Document::GetOriginalDocument() since that selection may have mutated after
+ * the print was invoked.
+ *
+ * Note also that because nsRange objects point into a specific document's
+ * nodes, we cannot reuse an array of nsRange objects across multiple static
+ * clone documents. For that reason we cache a new array of ranges on each
+ * static clone that we create.
+ */
+static void CachePrintSelectionRanges(const Document& aSourceDoc,
+                                      Document& aStaticClone) {
+  MOZ_ASSERT(aStaticClone.IsStaticDocument());
+  MOZ_ASSERT(!aStaticClone.GetProperty(nsGkAtoms::printselectionranges));
+
+  const Selection* origSelection = nullptr;
+  const nsTArray<RefPtr<nsRange>>* origRanges = nullptr;
+  bool sourceDocIsStatic = aSourceDoc.IsStaticDocument();
+
+  if (sourceDocIsStatic) {
+    origRanges = static_cast<nsTArray<RefPtr<nsRange>>*>(
+        aSourceDoc.GetProperty(nsGkAtoms::printselectionranges));
+  } else if (PresShell* shell = aSourceDoc.GetPresShell()) {
+    origSelection = shell->GetCurrentSelection(SelectionType::eNormal);
+  }
+
+  if (!origSelection && !origRanges) {
+    return;
+  }
+
+  size_t rangeCount =
+      sourceDocIsStatic ? origRanges->Length() : origSelection->RangeCount();
+  auto* printRanges = new nsTArray<RefPtr<nsRange>>(rangeCount);
+
+  for (size_t i = 0; i < rangeCount; ++i) {
+    nsRange* range = sourceDocIsStatic ? origRanges->ElementAt(i).get()
+                                       : origSelection->GetRangeAt(i);
+    nsINode* startContainer = range->GetStartContainer();
+    nsINode* endContainer = range->GetEndContainer();
+
+    if (!startContainer || !endContainer) {
+      continue;
+    }
+
+    nsINode* startNode =
+        GetCorrespondingNodeInDocument(startContainer, aStaticClone);
+    nsINode* endNode =
+        GetCorrespondingNodeInDocument(endContainer, aStaticClone);
+
+    if (!startNode || !endNode) {
+      continue;
+    }
+
+    RefPtr<nsRange> clonedRange =
+        nsRange::Create(startNode, range->StartOffset(), endNode,
+                        range->EndOffset(), IgnoreErrors());
+    if (clonedRange && !clonedRange->Collapsed()) {
+      printRanges->AppendElement(std::move(clonedRange));
+    }
+  }
+
+  aStaticClone.SetProperty(nsGkAtoms::printselectionranges, printRanges,
+                           nsINode::DeleteProperty<nsTArray<RefPtr<nsRange>>>);
+}
+
 nsresult nsPrintObject::InitAsRootObject(nsIDocShell* aDocShell, Document* aDoc,
                                          bool aForPrintPreview) {
   NS_ENSURE_STATE(aDocShell);
@@ -97,6 +201,7 @@ nsresult nsPrintObject::InitAsRootObject(nsIDocShell* aDocShell, Document* aDoc,
 
   mDocument = aDoc->CreateStaticClone(mDocShell);
   NS_ENSURE_STATE(mDocument);
+  CachePrintSelectionRanges(*aDoc, *mDocument);
 
   nsCOMPtr<nsIContentViewer> viewer;
   mDocShell->GetContentViewer(getter_AddRefs(viewer));

xpcom/ds/StaticAtoms.py

@@ -996,6 +996,7 @@ STATIC_ATOMS = [
     Atom("previewDiv", "preview-div"),
     Atom("primary", "primary"),
     Atom("print", "print"),
+    Atom("printselectionranges", "printselectionranges"),
     Atom("priority", "priority"),
     Atom("processingInstruction", "processing-instruction"),
     Atom("profile", "profile"),